paddleaudio as extenstion

.gitignore

@@ -16,6 +16,10 @@
 build
 *output/
 
+paddlespeech/audio/_paddleaudio.so
+paddlespeech/audio/lib/libpaddleaudio.so
+paddlespeech/version.py
+
 docs/build/
 docs/topic/ctc/warp-ctc/
 

CMakeLists.txt

-cmake_minimum_required(VERSION 3.16 FATAL_ERROR)
+cmake_minimum_required(VERSION 3.18 FATAL_ERROR)
+
+# Use compiler ID "AppleClang" instead of "Clang" for XCode.
+# Not setting this sometimes makes XCode C compiler gets detected as "Clang",
+# even when the C++ one is detected as "AppleClang".
+cmake_policy(SET CMP0010 NEW)
+cmake_policy(SET CMP0025 NEW)
+
+# Suppress warning flags in default MSVC configuration.  It's not
+# mandatory that we do this (and we don't if cmake is old), but it's
+# nice when it's possible, and it's possible on our Windows configs.
+if(NOT CMAKE_VERSION VERSION_LESS 3.15.0)
+  cmake_policy(SET CMP0092 NEW)
+endif()
 
 project(paddlespeech)
 
 # check and set CMAKE_CXX_STANDARD
 string(FIND "${CMAKE_CXX_FLAGS}" "-std=c++" env_cxx_standard)
+if(env_cxx_standard GREATER -1)
+  message(
+      WARNING "C++ standard version definition detected in environment variable."
+      "paddlespeech requires -std=c++14. Please remove -std=c++ settings in your environment.")
+endif()
 
 set(CMAKE_CXX_STANDARD 14)
 set(CMAKE_C_STANDARD 11)
+
 set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
 set(CMAKE_POSITION_INDEPENDENT_CODE ON)
+set(CMAKE_VERBOSE_MAKEFILE ON)
+
 
 # Options
 option(BUILD_SOX "Build libsox statically" ON)
+option(BUILD_MAD "Enable libmad" ON)
+option(BUILD_PADDLEAUDIO_PYTHON_EXTENSION "Build Python extension" ON)
+
+set(CMAKE_MODULE_PATH "${CMAKE_MODULE_PATH};${CMAKE_CURRENT_SOURCE_DIR}/cmake")
+
+find_package(Python3 COMPONENTS Interpreter Development)
+find_package(pybind11 CONFIG)
+message(STATUS "Python_INCLUDE_DIR=" ${Python_INCLUDE_DIR})
 
 add_subdirectory(paddlespeech/audio/third_party)
 add_subdirectory(paddlespeech/audio/src)

paddlespeech/__init__.py

@@ -14,3 +14,5 @@
 import _locale
 
 _locale._getdefaultlocale = (lambda *args: ['en_US', 'utf8'])
+
+

paddlespeech/audio/README.md

@@ -3,7 +3,29 @@
 ## Reference
 `csrc` code is reference of `torchaudio`.
 
+```text
 BSD 2-Clause License
 
-Copyright (c) 2017 Facebook Inc. (Soumith Chintala), 
-All rights reserved.
+Copyright (c) [year], [fullname]
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+1. Redistributions of source code must retain the above copyright notice, this
+   list of conditions and the following disclaimer.
+
+2. Redistributions in binary form must reproduce the above copyright notice,
+   this list of conditions and the following disclaimer in the documentation
+   and/or other materials provided with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+```
\ No newline at end of file

paddlespeech/audio/__init__.py

@@ -19,4 +19,4 @@ from . import io
 from . import metric
 from . import sox_effects
 from .backends import load
-from .backends import save
+from .backends import save
\ No newline at end of file

paddlespeech/audio/_class.py

+import types
+
+class _ClassNamespace(types.ModuleType):
+    def __init__(self, name):
+        super(_ClassNamespace, self).__init__('paddlespeech.classes' + name)
+        self.name = name
+
+    def __getattr__(self, attr):
+        proxy = None
+        if proxy is None:
+            raise RuntimeError(f'Class {self.name}.{attr} not registered!')
+        return proxy
+
+class _Classes(types.ModuleType):
+    __file__ = '_classes.py'
+
+    def __init__(self):
+        super(_Classes, self).__init__('paddlespeech.classes')
+
+    def __getattr__(self, name):
+        namespace = _ClassNamespace(name)
+        setattr(self, name, namespace)
+        return namespace
+
+    @property
+    def loaded_libraries(self):
+        return paddlespeech.ops.loaded_libraries
+
+    def load_library(self, path):
+        """
+        Loads a shared library from the given path into the current process.
+        The library being loaded may run global initialization code to register
+        custom classes with the PyTorch JIT runtime. This allows dynamically
+        loading custom classes. For this, you should compile your class
+        and the static registration code into a shared library object, and then
+        call ``torch.classes.load_library('path/to/libcustom.so')`` to load the
+        shared object.
+        After the library is loaded, it is added to the
+        ``torch.classes.loaded_libraries`` attribute, a set that may be inspected
+        for the paths of all libraries loaded using this function.
+        Args:
+            path (str): A path to a shared library to load.
+        """
+        paddlespeech.ops.load_library(path)
+
+# The classes "namespace"
+classes = _Classes()
\ No newline at end of file

paddlespeech/audio/_extension.py

+import os
+import warnings
+from pathlib import Path
+
+from ._internal import module_utils as _mod_utils  # noqa: F401
+
+_LIB_DIR = Path(__file__) / "lib"
+
+
+def _get_lib_path(lib: str):
+    suffix = "pyd" if os.name == "nt" else "so"
+    path = _LIB_DIR / f"{lib}.{suffix}"
+    return path
+
+
+def _load_lib(lib: str) -> bool:
+    """Load extension module
+    Note:
+        In case `paddleaudio` is deployed with `pex` format, the library file
+        is not in a standard location.
+        In this case, we expect that `libpaddlleaudio` is available somewhere
+        in the search path of dynamic loading mechanism, so that importing
+        `_paddlleaudio` will have library loader find and load `libpaddlleaudio`.
+        This is the reason why the function should not raising an error when the library
+        file is not found.
+    Returns:
+        bool:
+            True if the library file is found AND the library loaded without failure.
+            False if the library file is not found (like in the case where paddlleaudio
+            is deployed with pex format, thus the shared library file is
+            in a non-standard location.).
+            If the library file is found but there is an issue loading the library,
+            (such as missing dependency) then this function raises the exception as-is.
+    Raises:
+        Exception:
+            If the library file is found, but there is an issue loading the library file,
+            (when underlying `ctype.DLL` throws an exception), this function will pass
+            the exception as-is, instead of catching it and returning bool.
+            The expected case is `OSError` thrown by `ctype.DLL` when a dynamic dependency
+            is not found.
+            This behavior was chosen because the expected failure case is not recoverable.
+            If a dependency is missing, then users have to install it.
+    """
+    path = _get_lib_path(lib)
+    if not path.exists():
+        return False
+    paddlespeech.ops.load_library(path)
+    return True
+
+
+_FFMPEG_INITIALIZED = False
+
+
+def _init_ffmpeg():
+    global _FFMPEG_INITIALIZED
+    if _FFMPEG_INITIALIZED:
+        return
+
+    if not paddlespeech.ops.paddlleaudio.is_ffmpeg_available():
+        raise RuntimeError(
+            "paddlleaudio is not compiled with FFmpeg integration. Please set USE_FFMPEG=1 when compiling paddlleaudio."
+        )
+
+    try:
+        _load_lib("libpaddlleaudio_ffmpeg")
+    except OSError as err:
+        raise ImportError("FFmpeg libraries are not found. Please install FFmpeg.") from err
+
+    import paddllespeech._paddlleaudio_ffmpeg  # noqa
+
+    paddlespeech.ops.paddlleaudio.ffmpeg_init()
+    if paddlespeech.ops.paddlleaudio.ffmpeg_get_log_level() > 8:
+        paddlespeech.ops.paddlleaudio.ffmpeg_set_log_level(8)
+
+    _FFMPEG_INITIALIZED = True
+
+
+def _init_extension():
+    if not _mod_utils.is_module_available("paddlespeech._paddleaudio"):
+        warnings.warn("paddlespeech C++ extension is not available.")
+        return
+
+    _load_lib("libpaddleaudio")
+    # This import is for initializing the methods registered via PyBind11
+    # This has to happen after the base library is loaded
+    from paddlespeech import _paddleaudio  # noqa
+
+    # Because this part is executed as part of `import torchaudio`, we ignore the
+    # initialization failure.
+    # If the FFmpeg integration is not properly initialized, then detailed error
+    # will be raised when client code attempts to import the dedicated feature.
+    try:
+        _init_ffmpeg()
+    except Exception:
+        pass
+
+
+_init_extension()
\ No newline at end of file

paddlespeech/audio/_internal/module_utils.py

+import importlib.util
+import warnings
+from functools import wraps
+from typing import Optional
+
+def is_module_available(*modules: str) -> bool:
+    r"""Returns if a top-level module with :attr:`name` exists *without**
+    importing it. This is generally safer than try-catch block around a
+    `import X`. It avoids third party libraries breaking assumptions of some of
+    our tests, e.g., setting multiprocessing start method when imported
+    (see librosa/#747, torchvision/#544).
+    """
+    return all(importlib.util.find_spec(m) is not None for m in modules)
+
+
+def requires_module(*modules: str):
+    """Decorate function to give error message if invoked without required optional modules.
+    This decorator is to give better error message to users rather
+    than raising ``NameError:  name 'module' is not defined`` at random places.
+    """
+    missing = [m for m in modules if not is_module_available(m)]
+
+    if not missing:
+        # fall through. If all the modules are available, no need to decorate
+        def decorator(func):
+            return func
+
+    else:
+        req = f"module: {missing[0]}" if len(missing) == 1 else f"modules: {missing}"
+
+        def decorator(func):
+            @wraps(func)
+            def wrapped(*args, **kwargs):
+                raise RuntimeError(f"{func.__module__}.{func.__name__} requires {req}")
+
+            return wrapped
+
+    return decorator
+
+
+def deprecated(direction: str, version: Optional[str] = None):
+    """Decorator to add deprecation message
+    Args:
+        direction (str): Migration steps to be given to users.
+        version (str or int): The version when the object will be removed
+    """
+
+    def decorator(func):
+        @wraps(func)
+        def wrapped(*args, **kwargs):
+            message = (
+                f"{func.__module__}.{func.__name__} has been deprecated "
+                f'and will be removed from {"future" if version is None else version} release. '
+                f"{direction}"
+            )
+            warnings.warn(message, stacklevel=2)
+            return func(*args, **kwargs)
+
+        return wrapped
+
+    return decorator
+
+
+def is_kaldi_available():
+    return is_module_available("paddlespeech"._paddleaudio") and paddlespeech.ops.paddleaudio.is_kaldi_available()
+
+
+def requires_kaldi():
+    if is_kaldi_available():
+
+        def decorator(func):
+            return func
+
+    else:
+
+        def decorator(func):
+            @wraps(func)
+            def wrapped(*args, **kwargs):
+                raise RuntimeError(f"{func.__module__}.{func.__name__} requires kaldi")
+
+            return wrapped
+
+    return decorator
+
+
+def _check_soundfile_importable():
+    if not is_module_available("soundfile"):
+        return False
+    try:
+        import soundfile  # noqa: F401
+
+        return True
+    except Exception:
+        warnings.warn("Failed to import soundfile. 'soundfile' backend is not available.")
+        return False
+
+
+_is_soundfile_importable = _check_soundfile_importable()
+
+
+def is_soundfile_available():
+    return _is_soundfile_importable
+
+
+def requires_soundfile():
+    if is_soundfile_available():
+
+        def decorator(func):
+            return func
+
+    else:
+
+        def decorator(func):
+            @wraps(func)
+            def wrapped(*args, **kwargs):
+                raise RuntimeError(f"{func.__module__}.{func.__name__} requires soundfile")
+
+            return wrapped
+
+    return decorator
+
+
+def is_sox_available():
+    return is_module_available("paddlespeech._paddleaudio") and paddlespeech.ops.paddleaudio.is_sox_available()
+
+
+def requires_sox():
+    if is_sox_available():
+
+        def decorator(func):
+            return func
+
+    else:
+
+        def decorator(func):
+            @wraps(func)
+            def wrapped(*args, **kwargs):
+                raise RuntimeError(f"{func.__module__}.{func.__name__} requires sox")
+
+            return wrapped
+
+    return
\ No newline at end of file

paddlespeech/audio/_ops.py

+import contextlib
+import ctypes
+import sys
+import os
+import types
+
+# Query `hasattr` only once.
+_SET_GLOBAL_FLAGS = hasattr(sys, 'getdlopenflags') and hasattr(sys, 'setdlopenflags')
+
+
+@contextlib.contextmanager
+def dl_open_guard():
+    """
+    # https://manpages.debian.org/bullseye/manpages-dev/dlopen.3.en.html
+    Context manager to set the RTLD_GLOBAL dynamic linker flag while we open a
+    shared library to load custom operators.
+    """
+    if _SET_GLOBAL_FLAGS:
+        old_flags = sys.getdlopenflags()
+        sys.setdlopenflags(old_flags | ctypes.RTLD_GLOBAL)
+    yield
+    if _SET_GLOBAL_FLAGS:
+        sys.setdlopenflags(old_flags)
+
+        
+def resolve_library_path(path: str) -> str:
+    return os.path.realpath(path)
+
+
+class _Ops(types.ModuleType):
+    __file__ = '_ops.py'
+
+    def __init__(self):
+        super(_Ops, self).__init__('paddlespeech.ops')
+        self.loaded_libraries = set()
+
+    def load_library(self, path):
+        """
+        Loads a shared library from the given path into the current process.
+        This allows dynamically loading custom operators. For this, 
+        you should compile your operator and 
+        the static registration code into a shared library object, and then
+        call ``paddlespeech.ops.load_library('path/to/libcustom.so')`` to load the
+        shared object.
+        After the library is loaded, it is added to the
+        ``paddlespeech.ops.loaded_libraries`` attribute, a set that may be inspected
+        for the paths of all libraries loaded using this function.
+        Args:
+            path (str): A path to a shared library to load.
+        """
+        path = resolve_library_path(path)
+        with dl_open_guard():
+            # https://docs.python.org/3/library/ctypes.html?highlight=ctypes#loading-shared-libraries
+            # Import the shared library into the process, thus running its
+            # static (global) initialization code in order to register custom
+            # operators with the JIT.
+            ctypes.CDLL(path)
+        self.loaded_libraries.add(path)
+
+
+# The ops "namespace"
+ops = _Ops()
\ No newline at end of file

paddlespeech/audio/src/CMakeLists.txt

-find_package(Python3 COMPONENTS Interpreter Development)
-find_package(pybind11 CONFIG)
+if (MSVC)
+  set(CMAKE_WINDOWS_EXPORT_ALL_SYMBOLS ON)
+endif()
+
+################################################################################
+# libpaddleaudio
+################################################################################
+set(
+  LIBPADDLEAUDIO_SOURCES
+  utils.cpp
+  )
+
+set(
+  LIBPADDLEAUDIO_INCLUDE_DIRS
+  ${PROJECT_SOURCE_DIR}
+  )
+
+set(
+  LIBPADDLEAUDIO_LINK_LIBRARIES
+  )
+
+set(
+  LIBPADDLEAUDIO_COMPILE_DEFINITIONS)
 
-function(define_extension name sources libraries)
+#------------------------------------------------------------------------------#
+# START OF CUSTOMIZATION LOGICS
+#------------------------------------------------------------------------------#
+
+if(BUILD_SOX)
+  list(
+    APPEND
+    LIBPADDLEAUDIO_LINK_LIBRARIES
+    libsox
+    )
+  list(
+    APPEND
+    LIBPADDLEAUDIO_SOURCES
+    # sox/io.cpp
+    # sox/utils.cpp
+    # sox/effects.cpp
+    # sox/effects_chain.cpp
+    # sox/types.cpp
+    )
+  list(
+    APPEND
+    LIBPADDLEAUDIO_COMPILE_DEFINITIONS
+    INCLUDE_SOX
+    )
+endif()
+
+
+#------------------------------------------------------------------------------#
+# END OF CUSTOMIZATION LOGICS
+#------------------------------------------------------------------------------#
+
+function (define_library name source include_dirs link_libraries compile_defs)
+  add_library(${name} SHARED ${source})
+  target_include_directories(${name} PRIVATE ${include_dirs})
+  target_link_libraries(${name} ${link_libraries})
+  target_compile_definitions(${name} PRIVATE ${compile_defs})
+  set_target_properties(${name} PROPERTIES PREFIX "")
+  if (MSVC)
+    set_target_properties(${name} PROPERTIES SUFFIX ".pyd")
+  endif(MSVC)
+  install(
+    TARGETS ${name}
+    LIBRARY DESTINATION lib
+    RUNTIME DESTINATION lib  # For Windows
+    )
+endfunction()
+
+
+define_library(
+  libpaddleaudio
+  "${LIBPADDLEAUDIO_SOURCES}"
+  "${LIBPADDLEAUDIO_INCLUDE_DIRS}"
+  "${LIBPADDLEAUDIO_LINK_LIBRARIES}"
+  "${LIBPADDLEAUDIO_COMPILE_DEFINITIONS}"
+)
+
+if (APPLE)
+  set(TORCHAUDIO_LIBRARY libtorchaudio CACHE INTERNAL "")
+else()
+  set(TORCHAUDIO_LIBRARY -Wl,--no-as-needed libtorchaudio -Wl,--as-needed CACHE INTERNAL "")
+endif()
+
+  ################################################################################
+# _paddleaudio.so
+################################################################################
+if (BUILD_PADDLEAUDIO_PYTHON_EXTENSION)
+if (WIN32)
+  find_package(Python3 ${PYTHON_VERSION} EXACT COMPONENTS Development)
+  set(ADDITIONAL_ITEMS Python3::Python)
+endif()
+function(define_extension name sources include_dirs libraries definitions)
   add_library(${name} SHARED ${sources})
+  target_compile_definitions(${name} PRIVATE "${definitions}")
   target_include_directories(
-    ${name} PRIVATE ${PROJECT_SOURCE_DIR} ${CMAKE_CURRENT_SOURCE_DIR} ${Python3_INCLUDE_DIRS} ${pybind11_INCLUDE_DIR})
-  target_link_libraries(${name} ${libraries})
+    ${name} PRIVATE ${PROJECT_SOURCE_DIR} ${Python_INCLUDE_DIR} ${include_dirs})
+  target_link_libraries(
+    ${name}
+    ${libraries}
+    ${TORCH_PYTHON_LIBRARY}
+    ${ADDITIONAL_ITEMS}
+    )
   set_target_properties(${name} PROPERTIES PREFIX "")
+  if (MSVC)
+    set_target_properties(${name} PROPERTIES SUFFIX ".pyd")
+  endif(MSVC)
+  if (APPLE)
+    # https://github.com/facebookarchive/caffe2/issues/854#issuecomment-364538485
+    # https://github.com/pytorch/pytorch/commit/73f6715f4725a0723d8171d3131e09ac7abf0666
+    set_target_properties(${name} PROPERTIES LINK_FLAGS "-undefined dynamic_lookup")
+  endif()
   install(
     TARGETS ${name}
     LIBRARY DESTINATION .
+    RUNTIME DESTINATION .  # For Windows
     )
 endfunction()
 
+set(
+  EXTENSION_SOURCES
+  pybind/pybind.cpp
+  )
+#----------------------------------------------------------------------------#
+# START OF CUSTOMIZATION LOGICS
+#----------------------------------------------------------------------------#
 if(BUILD_SOX)
-  set(
+  list(
+    APPEND
     EXTENSION_SOURCES
-    pybind/pybind.cpp
+    # pybind/sox/effects.cpp
+    # pybind/sox/effects_chain.cpp
     pybind/sox/io.cpp
     pybind/sox/utils.cpp
     )
-
-  set(
-    LINK_LIBRARIES
-    libsox
-    )
-
-  define_extension(
-    _paddleaudio
-    "${EXTENSION_SOURCES}"
-    "${LINK_LIBRARIES}"
-    )
 endif()
-
-add_subdirectory(pybind/kaldi_frontend)
+#----------------------------------------------------------------------------#
+# END OF CUSTOMIZATION LOGICS
+#----------------------------------------------------------------------------#
+define_extension(
+  _paddleaudio
+  "${EXTENSION_SOURCES}"
+  ""
+  libpaddleaudio
+  "${LIBPADDLEAUDIO_COMPILE_DEFINITIONS}"
+  )
+# if(BUILD_CTC_DECODER)
+#   set(
+#     DECODER_EXTENSION_SOURCES
+#     decoder/bindings/pybind.cpp
+#     )
+#   define_extension(
+#     _paddleaudio_decoder
+#     "${DECODER_EXTENSION_SOURCES}"
+#     ""
+#     "libpaddleaudio_decoder"
+#     "${LIBPADDLEAUDIO_DECODER_DEFINITIONS}"
+#     )
+# endif()
+# if(USE_FFMPEG)
+#   set(
+#     FFMPEG_EXTENSION_SOURCES
+#     ffmpeg/pybind/typedefs.cpp
+#     ffmpeg/pybind/pybind.cpp
+#     ffmpeg/pybind/stream_reader.cpp
+#     )
+#   define_extension(
+#     _paddleaudio_ffmpeg
+#     "${FFMPEG_EXTENSION_SOURCES}"
+#     "${FFMPEG_INCLUDE_DIRS}"
+#     "libpaddleaudio_ffmpeg"
+#     "${LIBPADDLEAUDIO_DECODER_DEFINITIONS}"
+#     )
+# endif()
+endif()
\ No newline at end of file

paddlespeech/audio/src/optional/COPYING

+Creative Commons Legal Code
+
+CC0 1.0 Universal
+
+    CREATIVE COMMONS CORPORATION IS NOT A LAW FIRM AND DOES NOT PROVIDE
+    LEGAL SERVICES. DISTRIBUTION OF THIS DOCUMENT DOES NOT CREATE AN
+    ATTORNEY-CLIENT RELATIONSHIP. CREATIVE COMMONS PROVIDES THIS
+    INFORMATION ON AN "AS-IS" BASIS. CREATIVE COMMONS MAKES NO WARRANTIES
+    REGARDING THE USE OF THIS DOCUMENT OR THE INFORMATION OR WORKS
+    PROVIDED HEREUNDER, AND DISCLAIMS LIABILITY FOR DAMAGES RESULTING FROM
+    THE USE OF THIS DOCUMENT OR THE INFORMATION OR WORKS PROVIDED
+    HEREUNDER.
+
+Statement of Purpose
+
+The laws of most jurisdictions throughout the world automatically confer
+exclusive Copyright and Related Rights (defined below) upon the creator
+and subsequent owner(s) (each and all, an "owner") of an original work of
+authorship and/or a database (each, a "Work").
+
+Certain owners wish to permanently relinquish those rights to a Work for
+the purpose of contributing to a commons of creative, cultural and
+scientific works ("Commons") that the public can reliably and without fear
+of later claims of infringement build upon, modify, incorporate in other
+works, reuse and redistribute as freely as possible in any form whatsoever
+and for any purposes, including without limitation commercial purposes.
+These owners may contribute to the Commons to promote the ideal of a free
+culture and the further production of creative, cultural and scientific
+works, or to gain reputation or greater distribution for their Work in
+part through the use and efforts of others.
+
+For these and/or other purposes and motivations, and without any
+expectation of additional consideration or compensation, the person
+associating CC0 with a Work (the "Affirmer"), to the extent that he or she
+is an owner of Copyright and Related Rights in the Work, voluntarily
+elects to apply CC0 to the Work and publicly distribute the Work under its
+terms, with knowledge of his or her Copyright and Related Rights in the
+Work and the meaning and intended legal effect of CC0 on those rights.
+
+1. Copyright and Related Rights. A Work made available under CC0 may be
+protected by copyright and related or neighboring rights ("Copyright and
+Related Rights"). Copyright and Related Rights include, but are not
+limited to, the following:
+
+  i. the right to reproduce, adapt, distribute, perform, display,
+     communicate, and translate a Work;
+ ii. moral rights retained by the original author(s) and/or performer(s);
+iii. publicity and privacy rights pertaining to a person's image or
+     likeness depicted in a Work;
+ iv. rights protecting against unfair competition in regards to a Work,
+     subject to the limitations in paragraph 4(a), below;
+  v. rights protecting the extraction, dissemination, use and reuse of data
+     in a Work;
+ vi. database rights (such as those arising under Directive 96/9/EC of the
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paddlespeech/audio/src/optional/optional.hpp

+
+///
+// optional - An implementation of std::optional with extensions
+// Written in 2017 by Sy Brand (tartanllama@gmail.com, @TartanLlama)
+//
+// Documentation available at https://tl.tartanllama.xyz/
+//
+// To the extent possible under law, the author(s) have dedicated all
+// copyright and related and neighboring rights to this software to the
+// public domain worldwide. This software is distributed without any warranty.
+//
+// You should have received a copy of the CC0 Public Domain Dedication
+// along with this software. If not, see
+// <http://creativecommons.org/publicdomain/zero/1.0/>.
+// https://github.com/TartanLlama/optional
+///
+
+#ifndef TL_OPTIONAL_HPP
+#define TL_OPTIONAL_HPP
+
+#define TL_OPTIONAL_VERSION_MAJOR 1
+#define TL_OPTIONAL_VERSION_MINOR 0
+#define TL_OPTIONAL_VERSION_PATCH 0
+
+#include <exception>
+#include <functional>
+#include <new>
+#include <type_traits>
+#include <utility>
+
+#if (defined(_MSC_VER) && _MSC_VER == 1900)
+#define TL_OPTIONAL_MSVC2015
+#endif
+
+#if (defined(__GNUC__) && __GNUC__ == 4 && __GNUC_MINOR__ <= 9 &&              \
+     !defined(__clang__))
+#define TL_OPTIONAL_GCC49
+#endif
+
+#if (defined(__GNUC__) && __GNUC__ == 5 && __GNUC_MINOR__ <= 4 &&              \
+     !defined(__clang__))
+#define TL_OPTIONAL_GCC54
+#endif
+
+#if (defined(__GNUC__) && __GNUC__ == 5 && __GNUC_MINOR__ <= 5 &&              \
+     !defined(__clang__))
+#define TL_OPTIONAL_GCC55
+#endif
+
+#if (defined(__GNUC__) && __GNUC__ == 4 && __GNUC_MINOR__ <= 9 &&              \
+     !defined(__clang__))
+// GCC < 5 doesn't support overloading on const&& for member functions
+#define TL_OPTIONAL_NO_CONSTRR
+
+// GCC < 5 doesn't support some standard C++11 type traits
+#define TL_OPTIONAL_IS_TRIVIALLY_COPY_CONSTRUCTIBLE(T)                                     \
+  std::has_trivial_copy_constructor<T>::value
+#define TL_OPTIONAL_IS_TRIVIALLY_COPY_ASSIGNABLE(T) std::has_trivial_copy_assign<T>::value
+
+// This one will be different for GCC 5.7 if it's ever supported
+#define TL_OPTIONAL_IS_TRIVIALLY_DESTRUCTIBLE(T) std::is_trivially_destructible<T>::value
+
+// GCC 5 < v < 8 has a bug in is_trivially_copy_constructible which breaks std::vector
+// for non-copyable types
+#elif (defined(__GNUC__) && __GNUC__ < 8 &&                                                \
+     !defined(__clang__))
+#ifndef TL_GCC_LESS_8_TRIVIALLY_COPY_CONSTRUCTIBLE_MUTEX
+#define TL_GCC_LESS_8_TRIVIALLY_COPY_CONSTRUCTIBLE_MUTEX
+namespace tl {
+  namespace detail {
+      template<class T>
+      struct is_trivially_copy_constructible : std::is_trivially_copy_constructible<T>{};
+#ifdef _GLIBCXX_VECTOR
+      template<class T, class A>
+      struct is_trivially_copy_constructible<std::vector<T,A>>
+          : std::is_trivially_copy_constructible<T>{};
+#endif      
+  }
+}
+#endif
+
+#define TL_OPTIONAL_IS_TRIVIALLY_COPY_CONSTRUCTIBLE(T)                                     \
+    tl::detail::is_trivially_copy_constructible<T>::value
+#define TL_OPTIONAL_IS_TRIVIALLY_COPY_ASSIGNABLE(T)                                        \
+  std::is_trivially_copy_assignable<T>::value
+#define TL_OPTIONAL_IS_TRIVIALLY_DESTRUCTIBLE(T) std::is_trivially_destructible<T>::value
+#else
+#define TL_OPTIONAL_IS_TRIVIALLY_COPY_CONSTRUCTIBLE(T)                                     \
+  std::is_trivially_copy_constructible<T>::value
+#define TL_OPTIONAL_IS_TRIVIALLY_COPY_ASSIGNABLE(T)                                        \
+  std::is_trivially_copy_assignable<T>::value
+#define TL_OPTIONAL_IS_TRIVIALLY_DESTRUCTIBLE(T) std::is_trivially_destructible<T>::value
+#endif
+
+#if __cplusplus > 201103L
+#define TL_OPTIONAL_CXX14
+#endif
+
+// constexpr implies const in C++11, not C++14
+#if (__cplusplus == 201103L || defined(TL_OPTIONAL_MSVC2015) ||                \
+     defined(TL_OPTIONAL_GCC49))
+#define TL_OPTIONAL_11_CONSTEXPR
+#else
+#define TL_OPTIONAL_11_CONSTEXPR constexpr
+#endif
+
+namespace tl {
+#ifndef TL_MONOSTATE_INPLACE_MUTEX
+#define TL_MONOSTATE_INPLACE_MUTEX
+/// Used to represent an optional with no data; essentially a bool
+class monostate {};
+
+///  A tag type to tell optional to construct its value in-place
+struct in_place_t {
+  explicit in_place_t() = default;
+};
+/// A tag to tell optional to construct its value in-place
+static constexpr in_place_t in_place{};
+#endif
+
+template <class T> class optional;
+
+namespace detail {
+#ifndef TL_TRAITS_MUTEX
+#define TL_TRAITS_MUTEX
+// C++14-style aliases for brevity
+template <class T> using remove_const_t = typename std::remove_const<T>::type;
+template <class T>
+using remove_reference_t = typename std::remove_reference<T>::type;
+template <class T> using decay_t = typename std::decay<T>::type;
+template <bool E, class T = void>
+using enable_if_t = typename std::enable_if<E, T>::type;
+template <bool B, class T, class F>
+using conditional_t = typename std::conditional<B, T, F>::type;
+
+// std::conjunction from C++17
+template <class...> struct conjunction : std::true_type {};
+template <class B> struct conjunction<B> : B {};
+template <class B, class... Bs>
+struct conjunction<B, Bs...>
+    : std::conditional<bool(B::value), conjunction<Bs...>, B>::type {};
+
+#if defined(_LIBCPP_VERSION) && __cplusplus == 201103L
+#define TL_TRAITS_LIBCXX_MEM_FN_WORKAROUND
+#endif
+
+// In C++11 mode, there's an issue in libc++'s std::mem_fn
+// which results in a hard-error when using it in a noexcept expression
+// in some cases. This is a check to workaround the common failing case.
+#ifdef TL_TRAITS_LIBCXX_MEM_FN_WORKAROUND
+template <class T> struct is_pointer_to_non_const_member_func : std::false_type{};
+template <class T, class Ret, class... Args>
+struct is_pointer_to_non_const_member_func<Ret (T::*) (Args...)> : std::true_type{};
+template <class T, class Ret, class... Args>
+struct is_pointer_to_non_const_member_func<Ret (T::*) (Args...)&> : std::true_type{};
+template <class T, class Ret, class... Args>
+struct is_pointer_to_non_const_member_func<Ret (T::*) (Args...)&&> : std::true_type{};        
+template <class T, class Ret, class... Args>
+struct is_pointer_to_non_const_member_func<Ret (T::*) (Args...) volatile> : std::true_type{};
+template <class T, class Ret, class... Args>
+struct is_pointer_to_non_const_member_func<Ret (T::*) (Args...) volatile&> : std::true_type{};
+template <class T, class Ret, class... Args>
+struct is_pointer_to_non_const_member_func<Ret (T::*) (Args...) volatile&&> : std::true_type{};        
+
+template <class T> struct is_const_or_const_ref : std::false_type{};
+template <class T> struct is_const_or_const_ref<T const&> : std::true_type{};
+template <class T> struct is_const_or_const_ref<T const> : std::true_type{};    
+#endif
+
+// std::invoke from C++17
+// https://stackoverflow.com/questions/38288042/c11-14-invoke-workaround
+template <typename Fn, typename... Args,
+#ifdef TL_TRAITS_LIBCXX_MEM_FN_WORKAROUND
+          typename = enable_if_t<!(is_pointer_to_non_const_member_func<Fn>::value 
+                                 && is_const_or_const_ref<Args...>::value)>, 
+#endif
+          typename = enable_if_t<std::is_member_pointer<decay_t<Fn>>::value>,
+          int = 0>
+constexpr auto invoke(Fn &&f, Args &&... args) noexcept(
+    noexcept(std::mem_fn(f)(std::forward<Args>(args)...)))
+    -> decltype(std::mem_fn(f)(std::forward<Args>(args)...)) {
+  return std::mem_fn(f)(std::forward<Args>(args)...);
+}
+
+template <typename Fn, typename... Args,
+          typename = enable_if_t<!std::is_member_pointer<decay_t<Fn>>::value>>
+constexpr auto invoke(Fn &&f, Args &&... args) noexcept(
+    noexcept(std::forward<Fn>(f)(std::forward<Args>(args)...)))
+    -> decltype(std::forward<Fn>(f)(std::forward<Args>(args)...)) {
+  return std::forward<Fn>(f)(std::forward<Args>(args)...);
+}
+
+// std::invoke_result from C++17
+template <class F, class, class... Us> struct invoke_result_impl;
+
+template <class F, class... Us>
+struct invoke_result_impl<
+    F, decltype(detail::invoke(std::declval<F>(), std::declval<Us>()...), void()),
+    Us...> {
+  using type = decltype(detail::invoke(std::declval<F>(), std::declval<Us>()...));
+};
+
+template <class F, class... Us>
+using invoke_result = invoke_result_impl<F, void, Us...>;
+
+template <class F, class... Us>
+using invoke_result_t = typename invoke_result<F, Us...>::type;
+
+#if defined(_MSC_VER) && _MSC_VER <= 1900
+// TODO make a version which works with MSVC 2015
+template <class T, class U = T> struct is_swappable : std::true_type {};
+
+template <class T, class U = T> struct is_nothrow_swappable : std::true_type {};
+#else
+// https://stackoverflow.com/questions/26744589/what-is-a-proper-way-to-implement-is-swappable-to-test-for-the-swappable-concept
+namespace swap_adl_tests {
+// if swap ADL finds this then it would call std::swap otherwise (same
+// signature)
+struct tag {};
+
+template <class T> tag swap(T &, T &);
+template <class T, std::size_t N> tag swap(T (&a)[N], T (&b)[N]);
+
+// helper functions to test if an unqualified swap is possible, and if it
+// becomes std::swap
+template <class, class> std::false_type can_swap(...) noexcept(false);
+template <class T, class U,
+          class = decltype(swap(std::declval<T &>(), std::declval<U &>()))>
+std::true_type can_swap(int) noexcept(noexcept(swap(std::declval<T &>(),
+                                                    std::declval<U &>())));
+
+template <class, class> std::false_type uses_std(...);
+template <class T, class U>
+std::is_same<decltype(swap(std::declval<T &>(), std::declval<U &>())), tag>
+uses_std(int);
+
+template <class T>
+struct is_std_swap_noexcept
+    : std::integral_constant<bool,
+                             std::is_nothrow_move_constructible<T>::value &&
+                                 std::is_nothrow_move_assignable<T>::value> {};
+
+template <class T, std::size_t N>
+struct is_std_swap_noexcept<T[N]> : is_std_swap_noexcept<T> {};
+
+template <class T, class U>
+struct is_adl_swap_noexcept
+    : std::integral_constant<bool, noexcept(can_swap<T, U>(0))> {};
+} // namespace swap_adl_tests
+
+template <class T, class U = T>
+struct is_swappable
+    : std::integral_constant<
+          bool,
+          decltype(detail::swap_adl_tests::can_swap<T, U>(0))::value &&
+              (!decltype(detail::swap_adl_tests::uses_std<T, U>(0))::value ||
+               (std::is_move_assignable<T>::value &&
+                std::is_move_constructible<T>::value))> {};
+
+template <class T, std::size_t N>
+struct is_swappable<T[N], T[N]>
+    : std::integral_constant<
+          bool,
+          decltype(detail::swap_adl_tests::can_swap<T[N], T[N]>(0))::value &&
+              (!decltype(
+                   detail::swap_adl_tests::uses_std<T[N], T[N]>(0))::value ||
+               is_swappable<T, T>::value)> {};
+
+template <class T, class U = T>
+struct is_nothrow_swappable
+    : std::integral_constant<
+          bool,
+          is_swappable<T, U>::value &&
+              ((decltype(detail::swap_adl_tests::uses_std<T, U>(0))::value
+                    &&detail::swap_adl_tests::is_std_swap_noexcept<T>::value) ||
+               (!decltype(detail::swap_adl_tests::uses_std<T, U>(0))::value &&
+                    detail::swap_adl_tests::is_adl_swap_noexcept<T,
+                                                                 U>::value))> {
+};
+#endif
+#endif
+
+// std::void_t from C++17
+template <class...> struct voider { using type = void; };
+template <class... Ts> using void_t = typename voider<Ts...>::type;
+
+// Trait for checking if a type is a tl::optional
+template <class T> struct is_optional_impl : std::false_type {};
+template <class T> struct is_optional_impl<optional<T>> : std::true_type {};
+template <class T> using is_optional = is_optional_impl<decay_t<T>>;
+
+// Change void to tl::monostate
+template <class U>
+using fixup_void = conditional_t<std::is_void<U>::value, monostate, U>;
+
+template <class F, class U, class = invoke_result_t<F, U>>
+using get_map_return = optional<fixup_void<invoke_result_t<F, U>>>;
+
+// Check if invoking F for some Us returns void
+template <class F, class = void, class... U> struct returns_void_impl;
+template <class F, class... U>
+struct returns_void_impl<F, void_t<invoke_result_t<F, U...>>, U...>
+    : std::is_void<invoke_result_t<F, U...>> {};
+template <class F, class... U>
+using returns_void = returns_void_impl<F, void, U...>;
+
+template <class T, class... U>
+using enable_if_ret_void = enable_if_t<returns_void<T &&, U...>::value>;
+
+template <class T, class... U>
+using disable_if_ret_void = enable_if_t<!returns_void<T &&, U...>::value>;
+
+template <class T, class U>
+using enable_forward_value =
+    detail::enable_if_t<std::is_constructible<T, U &&>::value &&
+                        !std::is_same<detail::decay_t<U>, in_place_t>::value &&
+                        !std::is_same<optional<T>, detail::decay_t<U>>::value>;
+
+template <class T, class U, class Other>
+using enable_from_other = detail::enable_if_t<
+    std::is_constructible<T, Other>::value &&
+    !std::is_constructible<T, optional<U> &>::value &&
+    !std::is_constructible<T, optional<U> &&>::value &&
+    !std::is_constructible<T, const optional<U> &>::value &&
+    !std::is_constructible<T, const optional<U> &&>::value &&
+    !std::is_convertible<optional<U> &, T>::value &&
+    !std::is_convertible<optional<U> &&, T>::value &&
+    !std::is_convertible<const optional<U> &, T>::value &&
+    !std::is_convertible<const optional<U> &&, T>::value>;
+
+template <class T, class U>
+using enable_assign_forward = detail::enable_if_t<
+    !std::is_same<optional<T>, detail::decay_t<U>>::value &&
+    !detail::conjunction<std::is_scalar<T>,
+                         std::is_same<T, detail::decay_t<U>>>::value &&
+    std::is_constructible<T, U>::value && std::is_assignable<T &, U>::value>;
+
+template <class T, class U, class Other>
+using enable_assign_from_other = detail::enable_if_t<
+    std::is_constructible<T, Other>::value &&
+    std::is_assignable<T &, Other>::value &&
+    !std::is_constructible<T, optional<U> &>::value &&
+    !std::is_constructible<T, optional<U> &&>::value &&
+    !std::is_constructible<T, const optional<U> &>::value &&
+    !std::is_constructible<T, const optional<U> &&>::value &&
+    !std::is_convertible<optional<U> &, T>::value &&
+    !std::is_convertible<optional<U> &&, T>::value &&
+    !std::is_convertible<const optional<U> &, T>::value &&
+    !std::is_convertible<const optional<U> &&, T>::value &&
+    !std::is_assignable<T &, optional<U> &>::value &&
+    !std::is_assignable<T &, optional<U> &&>::value &&
+    !std::is_assignable<T &, const optional<U> &>::value &&
+    !std::is_assignable<T &, const optional<U> &&>::value>;
+
+// The storage base manages the actual storage, and correctly propagates
+// trivial destruction from T. This case is for when T is not trivially
+// destructible.
+template <class T, bool = ::std::is_trivially_destructible<T>::value>
+struct optional_storage_base {
+  TL_OPTIONAL_11_CONSTEXPR optional_storage_base() noexcept
+      : m_dummy(), m_has_value(false) {}
+
+  template <class... U>
+  TL_OPTIONAL_11_CONSTEXPR optional_storage_base(in_place_t, U &&... u)
+      : m_value(std::forward<U>(u)...), m_has_value(true) {}
+
+  ~optional_storage_base() {
+    if (m_has_value) {
+      m_value.~T();
+      m_has_value = false;
+    }
+  }
+
+  struct dummy {};
+  union {
+    dummy m_dummy;
+    T m_value;
+  };
+
+  bool m_has_value;
+};
+
+// This case is for when T is trivially destructible.
+template <class T> struct optional_storage_base<T, true> {
+  TL_OPTIONAL_11_CONSTEXPR optional_storage_base() noexcept
+      : m_dummy(), m_has_value(false) {}
+
+  template <class... U>
+  TL_OPTIONAL_11_CONSTEXPR optional_storage_base(in_place_t, U &&... u)
+      : m_value(std::forward<U>(u)...), m_has_value(true) {}
+
+  // No destructor, so this class is trivially destructible
+
+  struct dummy {};
+  union {
+    dummy m_dummy;
+    T m_value;
+  };
+
+  bool m_has_value = false;
+};
+
+// This base class provides some handy member functions which can be used in
+// further derived classes
+template <class T> struct optional_operations_base : optional_storage_base<T> {
+  using optional_storage_base<T>::optional_storage_base;
+
+  void hard_reset() noexcept {
+    get().~T();
+    this->m_has_value = false;
+  }
+
+  template <class... Args> void construct(Args &&... args) noexcept {
+    new (std::addressof(this->m_value)) T(std::forward<Args>(args)...);
+    this->m_has_value = true;
+  }
+
+  template <class Opt> void assign(Opt &&rhs) {
+    if (this->has_value()) {
+      if (rhs.has_value()) {
+        this->m_value = std::forward<Opt>(rhs).get();
+      } else {
+        this->m_value.~T();
+        this->m_has_value = false;
+      }
+    }
+
+    else if (rhs.has_value()) {
+      construct(std::forward<Opt>(rhs).get());
+    }
+  }
+
+  bool has_value() const { return this->m_has_value; }
+
+  TL_OPTIONAL_11_CONSTEXPR T &get() & { return this->m_value; }
+  TL_OPTIONAL_11_CONSTEXPR const T &get() const & { return this->m_value; }
+  TL_OPTIONAL_11_CONSTEXPR T &&get() && { return std::move(this->m_value); }
+#ifndef TL_OPTIONAL_NO_CONSTRR
+  constexpr const T &&get() const && { return std::move(this->m_value); }
+#endif
+};
+
+// This class manages conditionally having a trivial copy constructor
+// This specialization is for when T is trivially copy constructible
+template <class T, bool = TL_OPTIONAL_IS_TRIVIALLY_COPY_CONSTRUCTIBLE(T)>
+struct optional_copy_base : optional_operations_base<T> {
+  using optional_operations_base<T>::optional_operations_base;
+};
+
+// This specialization is for when T is not trivially copy constructible
+template <class T>
+struct optional_copy_base<T, false> : optional_operations_base<T> {
+  using optional_operations_base<T>::optional_operations_base;
+
+  optional_copy_base() = default;
+  optional_copy_base(const optional_copy_base &rhs)
+  : optional_operations_base<T>() {
+    if (rhs.has_value()) {
+      this->construct(rhs.get());
+    } else {
+      this->m_has_value = false;
+    }
+  }
+
+  optional_copy_base(optional_copy_base &&rhs) = default;
+  optional_copy_base &operator=(const optional_copy_base &rhs) = default;
+  optional_copy_base &operator=(optional_copy_base &&rhs) = default;
+};
+
+// This class manages conditionally having a trivial move constructor
+// Unfortunately there's no way to achieve this in GCC < 5 AFAIK, since it
+// doesn't implement an analogue to std::is_trivially_move_constructible. We
+// have to make do with a non-trivial move constructor even if T is trivially
+// move constructible
+#ifndef TL_OPTIONAL_GCC49
+template <class T, bool = std::is_trivially_move_constructible<T>::value>
+struct optional_move_base : optional_copy_base<T> {
+  using optional_copy_base<T>::optional_copy_base;
+};
+#else
+template <class T, bool = false> struct optional_move_base;
+#endif
+template <class T> struct optional_move_base<T, false> : optional_copy_base<T> {
+  using optional_copy_base<T>::optional_copy_base;
+
+  optional_move_base() = default;
+  optional_move_base(const optional_move_base &rhs) = default;
+
+  optional_move_base(optional_move_base &&rhs) noexcept(
+      std::is_nothrow_move_constructible<T>::value) {
+    if (rhs.has_value()) {
+      this->construct(std::move(rhs.get()));
+    } else {
+      this->m_has_value = false;
+    }
+  }
+  optional_move_base &operator=(const optional_move_base &rhs) = default;
+  optional_move_base &operator=(optional_move_base &&rhs) = default;
+};
+
+// This class manages conditionally having a trivial copy assignment operator
+template <class T, bool = TL_OPTIONAL_IS_TRIVIALLY_COPY_ASSIGNABLE(T) &&
+                          TL_OPTIONAL_IS_TRIVIALLY_COPY_CONSTRUCTIBLE(T) &&
+                          TL_OPTIONAL_IS_TRIVIALLY_DESTRUCTIBLE(T)>
+struct optional_copy_assign_base : optional_move_base<T> {
+  using optional_move_base<T>::optional_move_base;
+};
+
+template <class T>
+struct optional_copy_assign_base<T, false> : optional_move_base<T> {
+  using optional_move_base<T>::optional_move_base;
+
+  optional_copy_assign_base() = default;
+  optional_copy_assign_base(const optional_copy_assign_base &rhs) = default;
+
+  optional_copy_assign_base(optional_copy_assign_base &&rhs) = default;
+  optional_copy_assign_base &operator=(const optional_copy_assign_base &rhs) {
+    this->assign(rhs);
+    return *this;
+  }
+  optional_copy_assign_base &
+  operator=(optional_copy_assign_base &&rhs) = default;
+};
+
+// This class manages conditionally having a trivial move assignment operator
+// Unfortunately there's no way to achieve this in GCC < 5 AFAIK, since it
+// doesn't implement an analogue to std::is_trivially_move_assignable. We have
+// to make do with a non-trivial move assignment operator even if T is trivially
+// move assignable
+#ifndef TL_OPTIONAL_GCC49
+template <class T, bool = std::is_trivially_destructible<T>::value
+                       &&std::is_trivially_move_constructible<T>::value
+                           &&std::is_trivially_move_assignable<T>::value>
+struct optional_move_assign_base : optional_copy_assign_base<T> {
+  using optional_copy_assign_base<T>::optional_copy_assign_base;
+};
+#else
+template <class T, bool = false> struct optional_move_assign_base;
+#endif
+
+template <class T>
+struct optional_move_assign_base<T, false> : optional_copy_assign_base<T> {
+  using optional_copy_assign_base<T>::optional_copy_assign_base;
+
+  optional_move_assign_base() = default;
+  optional_move_assign_base(const optional_move_assign_base &rhs) = default;
+
+  optional_move_assign_base(optional_move_assign_base &&rhs) = default;
+
+  optional_move_assign_base &
+  operator=(const optional_move_assign_base &rhs) = default;
+
+  optional_move_assign_base &
+  operator=(optional_move_assign_base &&rhs) noexcept(
+      std::is_nothrow_move_constructible<T>::value
+          &&std::is_nothrow_move_assignable<T>::value) {
+    this->assign(std::move(rhs));
+    return *this;
+  }
+};
+
+// optional_delete_ctor_base will conditionally delete copy and move
+// constructors depending on whether T is copy/move constructible
+template <class T, bool EnableCopy = std::is_copy_constructible<T>::value,
+          bool EnableMove = std::is_move_constructible<T>::value>
+struct optional_delete_ctor_base {
+  optional_delete_ctor_base() = default;
+  optional_delete_ctor_base(const optional_delete_ctor_base &) = default;
+  optional_delete_ctor_base(optional_delete_ctor_base &&) noexcept = default;
+  optional_delete_ctor_base &
+  operator=(const optional_delete_ctor_base &) = default;
+  optional_delete_ctor_base &
+  operator=(optional_delete_ctor_base &&) noexcept = default;
+};
+
+template <class T> struct optional_delete_ctor_base<T, true, false> {
+  optional_delete_ctor_base() = default;
+  optional_delete_ctor_base(const optional_delete_ctor_base &) = default;
+  optional_delete_ctor_base(optional_delete_ctor_base &&) noexcept = delete;
+  optional_delete_ctor_base &
+  operator=(const optional_delete_ctor_base &) = default;
+  optional_delete_ctor_base &
+  operator=(optional_delete_ctor_base &&) noexcept = default;
+};
+
+template <class T> struct optional_delete_ctor_base<T, false, true> {
+  optional_delete_ctor_base() = default;
+  optional_delete_ctor_base(const optional_delete_ctor_base &) = delete;
+  optional_delete_ctor_base(optional_delete_ctor_base &&) noexcept = default;
+  optional_delete_ctor_base &
+  operator=(const optional_delete_ctor_base &) = default;
+  optional_delete_ctor_base &
+  operator=(optional_delete_ctor_base &&) noexcept = default;
+};
+
+template <class T> struct optional_delete_ctor_base<T, false, false> {
+  optional_delete_ctor_base() = default;
+  optional_delete_ctor_base(const optional_delete_ctor_base &) = delete;
+  optional_delete_ctor_base(optional_delete_ctor_base &&) noexcept = delete;
+  optional_delete_ctor_base &
+  operator=(const optional_delete_ctor_base &) = default;
+  optional_delete_ctor_base &
+  operator=(optional_delete_ctor_base &&) noexcept = default;
+};
+
+// optional_delete_assign_base will conditionally delete copy and move
+// constructors depending on whether T is copy/move constructible + assignable
+template <class T,
+          bool EnableCopy = (std::is_copy_constructible<T>::value &&
+                             std::is_copy_assignable<T>::value),
+          bool EnableMove = (std::is_move_constructible<T>::value &&
+                             std::is_move_assignable<T>::value)>
+struct optional_delete_assign_base {
+  optional_delete_assign_base() = default;
+  optional_delete_assign_base(const optional_delete_assign_base &) = default;
+  optional_delete_assign_base(optional_delete_assign_base &&) noexcept =
+      default;
+  optional_delete_assign_base &
+  operator=(const optional_delete_assign_base &) = default;
+  optional_delete_assign_base &
+  operator=(optional_delete_assign_base &&) noexcept = default;
+};
+
+template <class T> struct optional_delete_assign_base<T, true, false> {
+  optional_delete_assign_base() = default;
+  optional_delete_assign_base(const optional_delete_assign_base &) = default;
+  optional_delete_assign_base(optional_delete_assign_base &&) noexcept =
+      default;
+  optional_delete_assign_base &
+  operator=(const optional_delete_assign_base &) = default;
+  optional_delete_assign_base &
+  operator=(optional_delete_assign_base &&) noexcept = delete;
+};
+
+template <class T> struct optional_delete_assign_base<T, false, true> {
+  optional_delete_assign_base() = default;
+  optional_delete_assign_base(const optional_delete_assign_base &) = default;
+  optional_delete_assign_base(optional_delete_assign_base &&) noexcept =
+      default;
+  optional_delete_assign_base &
+  operator=(const optional_delete_assign_base &) = delete;
+  optional_delete_assign_base &
+  operator=(optional_delete_assign_base &&) noexcept = default;
+};
+
+template <class T> struct optional_delete_assign_base<T, false, false> {
+  optional_delete_assign_base() = default;
+  optional_delete_assign_base(const optional_delete_assign_base &) = default;
+  optional_delete_assign_base(optional_delete_assign_base &&) noexcept =
+      default;
+  optional_delete_assign_base &
+  operator=(const optional_delete_assign_base &) = delete;
+  optional_delete_assign_base &
+  operator=(optional_delete_assign_base &&) noexcept = delete;
+};
+
+} // namespace detail
+
+/// A tag type to represent an empty optional
+struct nullopt_t {
+  struct do_not_use {};
+  constexpr explicit nullopt_t(do_not_use, do_not_use) noexcept {}
+};
+/// Represents an empty optional
+static constexpr nullopt_t nullopt{nullopt_t::do_not_use{},
+                                   nullopt_t::do_not_use{}};
+
+class bad_optional_access : public std::exception {
+public:
+  bad_optional_access() = default;
+  const char *what() const noexcept { return "Optional has no value"; }
+};
+
+/// An optional object is an object that contains the storage for another
+/// object and manages the lifetime of this contained object, if any. The
+/// contained object may be initialized after the optional object has been
+/// initialized, and may be destroyed before the optional object has been
+/// destroyed. The initialization state of the contained object is tracked by
+/// the optional object.
+template <class T>
+class optional : private detail::optional_move_assign_base<T>,
+                 private detail::optional_delete_ctor_base<T>,
+                 private detail::optional_delete_assign_base<T> {
+  using base = detail::optional_move_assign_base<T>;
+
+  static_assert(!std::is_same<T, in_place_t>::value,
+                "instantiation of optional with in_place_t is ill-formed");
+  static_assert(!std::is_same<detail::decay_t<T>, nullopt_t>::value,
+                "instantiation of optional with nullopt_t is ill-formed");
+
+public:
+// The different versions for C++14 and 11 are needed because deduced return
+// types are not SFINAE-safe. This provides better support for things like
+// generic lambdas. C.f.
+// http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2017/p0826r0.html
+#if defined(TL_OPTIONAL_CXX14) && !defined(TL_OPTIONAL_GCC49) &&               \
+    !defined(TL_OPTIONAL_GCC54) && !defined(TL_OPTIONAL_GCC55)
+  /// Carries out some operation which returns an optional on the stored
+  /// object if there is one.
+  template <class F> TL_OPTIONAL_11_CONSTEXPR auto and_then(F &&f) & {
+    using result = detail::invoke_result_t<F, T &>;
+    static_assert(detail::is_optional<result>::value,
+                  "F must return an optional");
+
+    return has_value() ? detail::invoke(std::forward<F>(f), **this)
+                       : result(nullopt);
+  }
+
+  template <class F> TL_OPTIONAL_11_CONSTEXPR auto and_then(F &&f) && {
+    using result = detail::invoke_result_t<F, T &&>;
+    static_assert(detail::is_optional<result>::value,
+                  "F must return an optional");
+
+    return has_value() ? detail::invoke(std::forward<F>(f), std::move(**this))
+                       : result(nullopt);
+  }
+
+  template <class F> constexpr auto and_then(F &&f) const & {
+    using result = detail::invoke_result_t<F, const T &>;
+    static_assert(detail::is_optional<result>::value,
+                  "F must return an optional");
+
+    return has_value() ? detail::invoke(std::forward<F>(f), **this)
+                       : result(nullopt);
+  }
+
+#ifndef TL_OPTIONAL_NO_CONSTRR
+  template <class F> constexpr auto and_then(F &&f) const && {
+    using result = detail::invoke_result_t<F, const T &&>;
+    static_assert(detail::is_optional<result>::value,
+                  "F must return an optional");
+
+    return has_value() ? detail::invoke(std::forward<F>(f), std::move(**this))
+                       : result(nullopt);
+  }
+#endif
+#else
+  /// Carries out some operation which returns an optional on the stored
+  /// object if there is one.
+  template <class F>
+  TL_OPTIONAL_11_CONSTEXPR detail::invoke_result_t<F, T &> and_then(F &&f) & {
+    using result = detail::invoke_result_t<F, T &>;
+    static_assert(detail::is_optional<result>::value,
+                  "F must return an optional");
+
+    return has_value() ? detail::invoke(std::forward<F>(f), **this)
+                       : result(nullopt);
+  }
+
+  template <class F>
+  TL_OPTIONAL_11_CONSTEXPR detail::invoke_result_t<F, T &&> and_then(F &&f) && {
+    using result = detail::invoke_result_t<F, T &&>;
+    static_assert(detail::is_optional<result>::value,
+                  "F must return an optional");
+
+    return has_value() ? detail::invoke(std::forward<F>(f), std::move(**this))
+                       : result(nullopt);
+  }
+
+  template <class F>
+  constexpr detail::invoke_result_t<F, const T &> and_then(F &&f) const & {
+    using result = detail::invoke_result_t<F, const T &>;
+    static_assert(detail::is_optional<result>::value,
+                  "F must return an optional");
+
+    return has_value() ? detail::invoke(std::forward<F>(f), **this)
+                       : result(nullopt);
+  }
+
+#ifndef TL_OPTIONAL_NO_CONSTRR
+  template <class F>
+  constexpr detail::invoke_result_t<F, const T &&> and_then(F &&f) const && {
+    using result = detail::invoke_result_t<F, const T &&>;
+    static_assert(detail::is_optional<result>::value,
+                  "F must return an optional");
+
+    return has_value() ? detail::invoke(std::forward<F>(f), std::move(**this))
+                       : result(nullopt);
+  }
+#endif
+#endif
+
+#if defined(TL_OPTIONAL_CXX14) && !defined(TL_OPTIONAL_GCC49) &&               \
+    !defined(TL_OPTIONAL_GCC54) && !defined(TL_OPTIONAL_GCC55)
+  /// Carries out some operation on the stored object if there is one.
+  template <class F> TL_OPTIONAL_11_CONSTEXPR auto map(F &&f) & {
+    return optional_map_impl(*this, std::forward<F>(f));
+  }
+
+  template <class F> TL_OPTIONAL_11_CONSTEXPR auto map(F &&f) && {
+    return optional_map_impl(std::move(*this), std::forward<F>(f));
+  }
+
+  template <class F> constexpr auto map(F &&f) const & {
+    return optional_map_impl(*this, std::forward<F>(f));
+  }
+
+  template <class F> constexpr auto map(F &&f) const && {
+    return optional_map_impl(std::move(*this), std::forward<F>(f));
+  }
+#else
+  /// Carries out some operation on the stored object if there is one.
+  template <class F>
+  TL_OPTIONAL_11_CONSTEXPR decltype(optional_map_impl(std::declval<optional &>(),
+                                             std::declval<F &&>()))
+  map(F &&f) & {
+    return optional_map_impl(*this, std::forward<F>(f));
+  }
+
+  template <class F>
+  TL_OPTIONAL_11_CONSTEXPR decltype(optional_map_impl(std::declval<optional &&>(),
+                                             std::declval<F &&>()))
+  map(F &&f) && {
+    return optional_map_impl(std::move(*this), std::forward<F>(f));
+  }
+
+  template <class F>
+  constexpr decltype(optional_map_impl(std::declval<const optional &>(),
+                              std::declval<F &&>()))
+  map(F &&f) const & {
+    return optional_map_impl(*this, std::forward<F>(f));
+  }
+
+#ifndef TL_OPTIONAL_NO_CONSTRR
+  template <class F>
+  constexpr decltype(optional_map_impl(std::declval<const optional &&>(),
+                              std::declval<F &&>()))
+  map(F &&f) const && {
+    return optional_map_impl(std::move(*this), std::forward<F>(f));
+  }
+#endif
+#endif
+
+#if defined(TL_OPTIONAL_CXX14) && !defined(TL_OPTIONAL_GCC49) &&               \
+    !defined(TL_OPTIONAL_GCC54) && !defined(TL_OPTIONAL_GCC55)
+  /// Carries out some operation on the stored object if there is one.
+  template <class F> TL_OPTIONAL_11_CONSTEXPR auto transform(F&& f) & {
+    return optional_map_impl(*this, std::forward<F>(f));
+  }
+
+  template <class F> TL_OPTIONAL_11_CONSTEXPR auto transform(F&& f) && {
+    return optional_map_impl(std::move(*this), std::forward<F>(f));
+  }
+
+  template <class F> constexpr auto transform(F&& f) const & {
+    return optional_map_impl(*this, std::forward<F>(f));
+  }
+
+  template <class F> constexpr auto transform(F&& f) const && {
+    return optional_map_impl(std::move(*this), std::forward<F>(f));
+  }
+#else
+  /// Carries out some operation on the stored object if there is one.
+  template <class F>
+  TL_OPTIONAL_11_CONSTEXPR decltype(optional_map_impl(std::declval<optional&>(),
+    std::declval<F&&>()))
+    transform(F&& f) & {
+    return optional_map_impl(*this, std::forward<F>(f));
+  }
+
+  template <class F>
+  TL_OPTIONAL_11_CONSTEXPR decltype(optional_map_impl(std::declval<optional&&>(),
+    std::declval<F&&>()))
+    transform(F&& f) && {
+    return optional_map_impl(std::move(*this), std::forward<F>(f));
+  }
+
+  template <class F>
+  constexpr decltype(optional_map_impl(std::declval<const optional&>(),
+    std::declval<F&&>()))
+    transform(F&& f) const & {
+    return optional_map_impl(*this, std::forward<F>(f));
+  }
+
+#ifndef TL_OPTIONAL_NO_CONSTRR
+  template <class F>
+  constexpr decltype(optional_map_impl(std::declval<const optional&&>(),
+    std::declval<F&&>()))
+    transform(F&& f) const && {
+    return optional_map_impl(std::move(*this), std::forward<F>(f));
+  }
+#endif
+#endif
+
+  /// Calls `f` if the optional is empty
+  template <class F, detail::enable_if_ret_void<F> * = nullptr>
+  optional<T> TL_OPTIONAL_11_CONSTEXPR or_else(F &&f) & {
+    if (has_value())
+      return *this;
+
+    std::forward<F>(f)();
+    return nullopt;
+  }
+
+  template <class F, detail::disable_if_ret_void<F> * = nullptr>
+  optional<T> TL_OPTIONAL_11_CONSTEXPR or_else(F &&f) & {
+    return has_value() ? *this : std::forward<F>(f)();
+  }
+
+  template <class F, detail::enable_if_ret_void<F> * = nullptr>
+  optional<T> or_else(F &&f) && {
+    if (has_value())
+      return std::move(*this);
+
+    std::forward<F>(f)();
+    return nullopt;
+  }
+
+  template <class F, detail::disable_if_ret_void<F> * = nullptr>
+  optional<T> TL_OPTIONAL_11_CONSTEXPR or_else(F &&f) && {
+    return has_value() ? std::move(*this) : std::forward<F>(f)();
+  }
+
+  template <class F, detail::enable_if_ret_void<F> * = nullptr>
+  optional<T> or_else(F &&f) const & {
+    if (has_value())
+      return *this;
+
+    std::forward<F>(f)();
+    return nullopt;
+  }
+
+  template <class F, detail::disable_if_ret_void<F> * = nullptr>
+  optional<T> TL_OPTIONAL_11_CONSTEXPR or_else(F &&f) const & {
+    return has_value() ? *this : std::forward<F>(f)();
+  }
+
+#ifndef TL_OPTIONAL_NO_CONSTRR
+  template <class F, detail::enable_if_ret_void<F> * = nullptr>
+  optional<T> or_else(F &&f) const && {
+    if (has_value())
+      return std::move(*this);
+
+    std::forward<F>(f)();
+    return nullopt;
+  }
+
+  template <class F, detail::disable_if_ret_void<F> * = nullptr>
+  optional<T> or_else(F &&f) const && {
+    return has_value() ? std::move(*this) : std::forward<F>(f)();
+  }
+#endif
+
+  /// Maps the stored value with `f` if there is one, otherwise returns `u`.
+  template <class F, class U> U map_or(F &&f, U &&u) & {
+    return has_value() ? detail::invoke(std::forward<F>(f), **this)
+                       : std::forward<U>(u);
+  }
+
+  template <class F, class U> U map_or(F &&f, U &&u) && {
+    return has_value() ? detail::invoke(std::forward<F>(f), std::move(**this))
+                       : std::forward<U>(u);
+  }
+
+  template <class F, class U> U map_or(F &&f, U &&u) const & {
+    return has_value() ? detail::invoke(std::forward<F>(f), **this)
+                       : std::forward<U>(u);
+  }
+
+#ifndef TL_OPTIONAL_NO_CONSTRR
+  template <class F, class U> U map_or(F &&f, U &&u) const && {
+    return has_value() ? detail::invoke(std::forward<F>(f), std::move(**this))
+                       : std::forward<U>(u);
+  }
+#endif
+
+  /// Maps the stored value with `f` if there is one, otherwise calls
+  /// `u` and returns the result.
+  template <class F, class U>
+  detail::invoke_result_t<U> map_or_else(F &&f, U &&u) & {
+    return has_value() ? detail::invoke(std::forward<F>(f), **this)
+                       : std::forward<U>(u)();
+  }
+
+  template <class F, class U>
+  detail::invoke_result_t<U> map_or_else(F &&f, U &&u) && {
+    return has_value() ? detail::invoke(std::forward<F>(f), std::move(**this))
+                       : std::forward<U>(u)();
+  }
+
+  template <class F, class U>
+  detail::invoke_result_t<U> map_or_else(F &&f, U &&u) const & {
+    return has_value() ? detail::invoke(std::forward<F>(f), **this)
+                       : std::forward<U>(u)();
+  }
+
+#ifndef TL_OPTIONAL_NO_CONSTRR
+  template <class F, class U>
+  detail::invoke_result_t<U> map_or_else(F &&f, U &&u) const && {
+    return has_value() ? detail::invoke(std::forward<F>(f), std::move(**this))
+                       : std::forward<U>(u)();
+  }
+#endif
+
+  /// Returns `u` if `*this` has a value, otherwise an empty optional.
+  template <class U>
+  constexpr optional<typename std::decay<U>::type> conjunction(U &&u) const {
+    using result = optional<detail::decay_t<U>>;
+    return has_value() ? result{u} : result{nullopt};
+  }
+
+  /// Returns `rhs` if `*this` is empty, otherwise the current value.
+  TL_OPTIONAL_11_CONSTEXPR optional disjunction(const optional &rhs) & {
+    return has_value() ? *this : rhs;
+  }
+
+  constexpr optional disjunction(const optional &rhs) const & {
+    return has_value() ? *this : rhs;
+  }
+
+  TL_OPTIONAL_11_CONSTEXPR optional disjunction(const optional &rhs) && {
+    return has_value() ? std::move(*this) : rhs;
+  }
+
+#ifndef TL_OPTIONAL_NO_CONSTRR
+  constexpr optional disjunction(const optional &rhs) const && {
+    return has_value() ? std::move(*this) : rhs;
+  }
+#endif
+
+  TL_OPTIONAL_11_CONSTEXPR optional disjunction(optional &&rhs) & {
+    return has_value() ? *this : std::move(rhs);
+  }
+
+  constexpr optional disjunction(optional &&rhs) const & {
+    return has_value() ? *this : std::move(rhs);
+  }
+
+  TL_OPTIONAL_11_CONSTEXPR optional disjunction(optional &&rhs) && {
+    return has_value() ? std::move(*this) : std::move(rhs);
+  }
+
+#ifndef TL_OPTIONAL_NO_CONSTRR
+  constexpr optional disjunction(optional &&rhs) const && {
+    return has_value() ? std::move(*this) : std::move(rhs);
+  }
+#endif
+
+  /// Takes the value out of the optional, leaving it empty
+  optional take() {
+    optional ret = std::move(*this);
+    reset();
+    return ret;
+  }
+
+  using value_type = T;
+
+  /// Constructs an optional that does not contain a value.
+  constexpr optional() noexcept = default;
+
+  constexpr optional(nullopt_t) noexcept {}
+
+  /// Copy constructor
+  ///
+  /// If `rhs` contains a value, the stored value is direct-initialized with
+  /// it. Otherwise, the constructed optional is empty.
+  TL_OPTIONAL_11_CONSTEXPR optional(const optional &rhs) = default;
+
+  /// Move constructor
+  ///
+  /// If `rhs` contains a value, the stored value is direct-initialized with
+  /// it. Otherwise, the constructed optional is empty.
+  TL_OPTIONAL_11_CONSTEXPR optional(optional &&rhs) = default;
+
+  /// Constructs the stored value in-place using the given arguments.
+ template <class... Args>
+  constexpr explicit optional(
+      detail::enable_if_t<std::is_constructible<T, Args...>::value, in_place_t>,
+      Args &&... args)
+      : base(in_place, std::forward<Args>(args)...) {}
+
+  template <class U, class... Args>
+  TL_OPTIONAL_11_CONSTEXPR explicit optional(
+      detail::enable_if_t<std::is_constructible<T, std::initializer_list<U> &,
+                                                Args &&...>::value,
+                          in_place_t>,
+      std::initializer_list<U> il, Args &&... args) {
+    this->construct(il, std::forward<Args>(args)...);
+  }
+
+  /// Constructs the stored value with `u`.
+  template <
+      class U = T,
+      detail::enable_if_t<std::is_convertible<U &&, T>::value> * = nullptr,
+      detail::enable_forward_value<T, U> * = nullptr>
+  constexpr optional(U &&u) : base(in_place, std::forward<U>(u)) {}
+
+  template <
+      class U = T,
+      detail::enable_if_t<!std::is_convertible<U &&, T>::value> * = nullptr,
+      detail::enable_forward_value<T, U> * = nullptr>
+  constexpr explicit optional(U &&u) : base(in_place, std::forward<U>(u)) {}
+
+  /// Converting copy constructor.
+  template <
+      class U, detail::enable_from_other<T, U, const U &> * = nullptr,
+      detail::enable_if_t<std::is_convertible<const U &, T>::value> * = nullptr>
+  optional(const optional<U> &rhs) {
+    if (rhs.has_value()) {
+      this->construct(*rhs);
+    }
+  }
+
+  template <class U, detail::enable_from_other<T, U, const U &> * = nullptr,
+            detail::enable_if_t<!std::is_convertible<const U &, T>::value> * =
+                nullptr>
+  explicit optional(const optional<U> &rhs) {
+    if (rhs.has_value()) {
+      this->construct(*rhs);
+    }
+  }
+
+  /// Converting move constructor.
+  template <
+      class U, detail::enable_from_other<T, U, U &&> * = nullptr,
+      detail::enable_if_t<std::is_convertible<U &&, T>::value> * = nullptr>
+  optional(optional<U> &&rhs) {
+    if (rhs.has_value()) {
+      this->construct(std::move(*rhs));
+    }
+  }
+
+  template <
+      class U, detail::enable_from_other<T, U, U &&> * = nullptr,
+      detail::enable_if_t<!std::is_convertible<U &&, T>::value> * = nullptr>
+  explicit optional(optional<U> &&rhs) {
+    if (rhs.has_value()) {
+      this->construct(std::move(*rhs));
+    }
+  }
+
+  /// Destroys the stored value if there is one.
+  ~optional() = default;
+
+  /// Assignment to empty.
+  ///
+  /// Destroys the current value if there is one.
+  optional &operator=(nullopt_t) noexcept {
+    if (has_value()) {
+      this->m_value.~T();
+      this->m_has_value = false;
+    }
+
+    return *this;
+  }
+
+  /// Copy assignment.
+  ///
+  /// Copies the value from `rhs` if there is one. Otherwise resets the stored
+  /// value in `*this`.
+  optional &operator=(const optional &rhs) = default;
+
+  /// Move assignment.
+  ///
+  /// Moves the value from `rhs` if there is one. Otherwise resets the stored
+  /// value in `*this`.
+  optional &operator=(optional &&rhs) = default;
+
+  /// Assigns the stored value from `u`, destroying the old value if there was
+  /// one.
+  template <class U = T, detail::enable_assign_forward<T, U> * = nullptr>
+  optional &operator=(U &&u) {
+    if (has_value()) {
+      this->m_value = std::forward<U>(u);
+    } else {
+      this->construct(std::forward<U>(u));
+    }
+
+    return *this;
+  }
+
+  /// Converting copy assignment operator.
+  ///
+  /// Copies the value from `rhs` if there is one. Otherwise resets the stored
+  /// value in `*this`.
+  template <class U,
+            detail::enable_assign_from_other<T, U, const U &> * = nullptr>
+  optional &operator=(const optional<U> &rhs) {
+    if (has_value()) {
+      if (rhs.has_value()) {
+        this->m_value = *rhs;
+      } else {
+        this->hard_reset();
+      }
+    }
+
+    if (rhs.has_value()) {
+      this->construct(*rhs);
+    }
+
+    return *this;
+  }
+
+  // TODO check exception guarantee
+  /// Converting move assignment operator.
+  ///
+  /// Moves the value from `rhs` if there is one. Otherwise resets the stored
+  /// value in `*this`.
+  template <class U, detail::enable_assign_from_other<T, U, U> * = nullptr>
+  optional &operator=(optional<U> &&rhs) {
+    if (has_value()) {
+      if (rhs.has_value()) {
+        this->m_value = std::move(*rhs);
+      } else {
+        this->hard_reset();
+      }
+    }
+
+    if (rhs.has_value()) {
+      this->construct(std::move(*rhs));
+    }
+
+    return *this;
+  }
+
+  /// Constructs the value in-place, destroying the current one if there is
+  /// one.
+  template <class... Args> T &emplace(Args &&... args) {
+    static_assert(std::is_constructible<T, Args &&...>::value,
+                  "T must be constructible with Args");
+
+    *this = nullopt;
+    this->construct(std::forward<Args>(args)...);
+    return value();
+  }
+
+  template <class U, class... Args>
+  detail::enable_if_t<
+      std::is_constructible<T, std::initializer_list<U> &, Args &&...>::value,
+      T &>
+  emplace(std::initializer_list<U> il, Args &&... args) {
+    *this = nullopt;
+    this->construct(il, std::forward<Args>(args)...);
+    return value();    
+  }
+
+  /// Swaps this optional with the other.
+  ///
+  /// If neither optionals have a value, nothing happens.
+  /// If both have a value, the values are swapped.
+  /// If one has a value, it is moved to the other and the movee is left
+  /// valueless.
+  void
+  swap(optional &rhs) noexcept(std::is_nothrow_move_constructible<T>::value
+                                   &&detail::is_nothrow_swappable<T>::value) {
+    using std::swap;
+    if (has_value()) {
+      if (rhs.has_value()) {
+        swap(**this, *rhs);
+      } else {
+        new (std::addressof(rhs.m_value)) T(std::move(this->m_value));
+        this->m_value.T::~T();
+      }
+    } else if (rhs.has_value()) {
+      new (std::addressof(this->m_value)) T(std::move(rhs.m_value));
+      rhs.m_value.T::~T();
+    }
+    swap(this->m_has_value, rhs.m_has_value);
+  }
+
+  /// Returns a pointer to the stored value
+  constexpr const T *operator->() const {
+    return std::addressof(this->m_value);
+  }
+
+  TL_OPTIONAL_11_CONSTEXPR T *operator->() {
+    return std::addressof(this->m_value);
+  }
+
+  /// Returns the stored value
+  TL_OPTIONAL_11_CONSTEXPR T &operator*() & { return this->m_value; }
+
+  constexpr const T &operator*() const & { return this->m_value; }
+
+  TL_OPTIONAL_11_CONSTEXPR T &&operator*() && {
+    return std::move(this->m_value);
+  }
+
+#ifndef TL_OPTIONAL_NO_CONSTRR
+  constexpr const T &&operator*() const && { return std::move(this->m_value); }
+#endif
+
+  /// Returns whether or not the optional has a value
+  constexpr bool has_value() const noexcept { return this->m_has_value; }
+
+  constexpr explicit operator bool() const noexcept {
+    return this->m_has_value;
+  }
+
+  /// Returns the contained value if there is one, otherwise throws bad_optional_access
+  TL_OPTIONAL_11_CONSTEXPR T &value() & {
+    if (has_value())
+      return this->m_value;
+    throw bad_optional_access();
+  }
+  TL_OPTIONAL_11_CONSTEXPR const T &value() const & {
+    if (has_value())
+      return this->m_value;
+    throw bad_optional_access();
+  }
+  TL_OPTIONAL_11_CONSTEXPR T &&value() && {
+    if (has_value())
+      return std::move(this->m_value);
+    throw bad_optional_access();
+  }
+
+#ifndef TL_OPTIONAL_NO_CONSTRR
+  TL_OPTIONAL_11_CONSTEXPR const T &&value() const && {
+    if (has_value())
+      return std::move(this->m_value);
+    throw bad_optional_access();
+  }
+#endif
+
+  /// Returns the stored value if there is one, otherwise returns `u`
+  template <class U> constexpr T value_or(U &&u) const & {
+    static_assert(std::is_copy_constructible<T>::value &&
+                      std::is_convertible<U &&, T>::value,
+                  "T must be copy constructible and convertible from U");
+    return has_value() ? **this : static_cast<T>(std::forward<U>(u));
+  }
+
+  template <class U> TL_OPTIONAL_11_CONSTEXPR T value_or(U &&u) && {
+    static_assert(std::is_move_constructible<T>::value &&
+                      std::is_convertible<U &&, T>::value,
+                  "T must be move constructible and convertible from U");
+    return has_value() ? **this : static_cast<T>(std::forward<U>(u));
+  }
+
+  /// Destroys the stored value if one exists, making the optional empty
+  void reset() noexcept {
+    if (has_value()) {
+      this->m_value.~T();
+      this->m_has_value = false;
+    }
+  }
+}; // namespace tl
+
+/// Compares two optional objects
+template <class T, class U>
+inline constexpr bool operator==(const optional<T> &lhs,
+                                 const optional<U> &rhs) {
+  return lhs.has_value() == rhs.has_value() &&
+         (!lhs.has_value() || *lhs == *rhs);
+}
+template <class T, class U>
+inline constexpr bool operator!=(const optional<T> &lhs,
+                                 const optional<U> &rhs) {
+  return lhs.has_value() != rhs.has_value() ||
+         (lhs.has_value() && *lhs != *rhs);
+}
+template <class T, class U>
+inline constexpr bool operator<(const optional<T> &lhs,
+                                const optional<U> &rhs) {
+  return rhs.has_value() && (!lhs.has_value() || *lhs < *rhs);
+}
+template <class T, class U>
+inline constexpr bool operator>(const optional<T> &lhs,
+                                const optional<U> &rhs) {
+  return lhs.has_value() && (!rhs.has_value() || *lhs > *rhs);
+}
+template <class T, class U>
+inline constexpr bool operator<=(const optional<T> &lhs,
+                                 const optional<U> &rhs) {
+  return !lhs.has_value() || (rhs.has_value() && *lhs <= *rhs);
+}
+template <class T, class U>
+inline constexpr bool operator>=(const optional<T> &lhs,
+                                 const optional<U> &rhs) {
+  return !rhs.has_value() || (lhs.has_value() && *lhs >= *rhs);
+}
+
+/// Compares an optional to a `nullopt`
+template <class T>
+inline constexpr bool operator==(const optional<T> &lhs, nullopt_t) noexcept {
+  return !lhs.has_value();
+}
+template <class T>
+inline constexpr bool operator==(nullopt_t, const optional<T> &rhs) noexcept {
+  return !rhs.has_value();
+}
+template <class T>
+inline constexpr bool operator!=(const optional<T> &lhs, nullopt_t) noexcept {
+  return lhs.has_value();
+}
+template <class T>
+inline constexpr bool operator!=(nullopt_t, const optional<T> &rhs) noexcept {
+  return rhs.has_value();
+}
+template <class T>
+inline constexpr bool operator<(const optional<T> &, nullopt_t) noexcept {
+  return false;
+}
+template <class T>
+inline constexpr bool operator<(nullopt_t, const optional<T> &rhs) noexcept {
+  return rhs.has_value();
+}
+template <class T>
+inline constexpr bool operator<=(const optional<T> &lhs, nullopt_t) noexcept {
+  return !lhs.has_value();
+}
+template <class T>
+inline constexpr bool operator<=(nullopt_t, const optional<T> &) noexcept {
+  return true;
+}
+template <class T>
+inline constexpr bool operator>(const optional<T> &lhs, nullopt_t) noexcept {
+  return lhs.has_value();
+}
+template <class T>
+inline constexpr bool operator>(nullopt_t, const optional<T> &) noexcept {
+  return false;
+}
+template <class T>
+inline constexpr bool operator>=(const optional<T> &, nullopt_t) noexcept {
+  return true;
+}
+template <class T>
+inline constexpr bool operator>=(nullopt_t, const optional<T> &rhs) noexcept {
+  return !rhs.has_value();
+}
+
+/// Compares the optional with a value.
+template <class T, class U>
+inline constexpr bool operator==(const optional<T> &lhs, const U &rhs) {
+  return lhs.has_value() ? *lhs == rhs : false;
+}
+template <class T, class U>
+inline constexpr bool operator==(const U &lhs, const optional<T> &rhs) {
+  return rhs.has_value() ? lhs == *rhs : false;
+}
+template <class T, class U>
+inline constexpr bool operator!=(const optional<T> &lhs, const U &rhs) {
+  return lhs.has_value() ? *lhs != rhs : true;
+}
+template <class T, class U>
+inline constexpr bool operator!=(const U &lhs, const optional<T> &rhs) {
+  return rhs.has_value() ? lhs != *rhs : true;
+}
+template <class T, class U>
+inline constexpr bool operator<(const optional<T> &lhs, const U &rhs) {
+  return lhs.has_value() ? *lhs < rhs : true;
+}
+template <class T, class U>
+inline constexpr bool operator<(const U &lhs, const optional<T> &rhs) {
+  return rhs.has_value() ? lhs < *rhs : false;
+}
+template <class T, class U>
+inline constexpr bool operator<=(const optional<T> &lhs, const U &rhs) {
+  return lhs.has_value() ? *lhs <= rhs : true;
+}
+template <class T, class U>
+inline constexpr bool operator<=(const U &lhs, const optional<T> &rhs) {
+  return rhs.has_value() ? lhs <= *rhs : false;
+}
+template <class T, class U>
+inline constexpr bool operator>(const optional<T> &lhs, const U &rhs) {
+  return lhs.has_value() ? *lhs > rhs : false;
+}
+template <class T, class U>
+inline constexpr bool operator>(const U &lhs, const optional<T> &rhs) {
+  return rhs.has_value() ? lhs > *rhs : true;
+}
+template <class T, class U>
+inline constexpr bool operator>=(const optional<T> &lhs, const U &rhs) {
+  return lhs.has_value() ? *lhs >= rhs : false;
+}
+template <class T, class U>
+inline constexpr bool operator>=(const U &lhs, const optional<T> &rhs) {
+  return rhs.has_value() ? lhs >= *rhs : true;
+}
+
+template <class T,
+          detail::enable_if_t<std::is_move_constructible<T>::value> * = nullptr,
+          detail::enable_if_t<detail::is_swappable<T>::value> * = nullptr>
+void swap(optional<T> &lhs,
+          optional<T> &rhs) noexcept(noexcept(lhs.swap(rhs))) {
+  return lhs.swap(rhs);
+}
+
+namespace detail {
+struct i_am_secret {};
+} // namespace detail
+
+template <class T = detail::i_am_secret, class U,
+          class Ret =
+              detail::conditional_t<std::is_same<T, detail::i_am_secret>::value,
+                                    detail::decay_t<U>, T>>
+inline constexpr optional<Ret> make_optional(U &&v) {
+  return optional<Ret>(std::forward<U>(v));
+}
+
+template <class T, class... Args>
+inline constexpr optional<T> make_optional(Args &&... args) {
+  return optional<T>(in_place, std::forward<Args>(args)...);
+}
+template <class T, class U, class... Args>
+inline constexpr optional<T> make_optional(std::initializer_list<U> il,
+                                           Args &&... args) {
+  return optional<T>(in_place, il, std::forward<Args>(args)...);
+}
+
+#if __cplusplus >= 201703L
+template <class T> optional(T)->optional<T>;
+#endif
+
+/// \exclude
+namespace detail {
+#ifdef TL_OPTIONAL_CXX14
+template <class Opt, class F,
+          class Ret = decltype(detail::invoke(std::declval<F>(),
+                                              *std::declval<Opt>())),
+          detail::enable_if_t<!std::is_void<Ret>::value> * = nullptr>
+constexpr auto optional_map_impl(Opt &&opt, F &&f) {
+  return opt.has_value()
+             ? detail::invoke(std::forward<F>(f), *std::forward<Opt>(opt))
+             : optional<Ret>(nullopt);
+}
+
+template <class Opt, class F,
+          class Ret = decltype(detail::invoke(std::declval<F>(),
+                                              *std::declval<Opt>())),
+          detail::enable_if_t<std::is_void<Ret>::value> * = nullptr>
+auto optional_map_impl(Opt &&opt, F &&f) {
+  if (opt.has_value()) {
+    detail::invoke(std::forward<F>(f), *std::forward<Opt>(opt));
+    return make_optional(monostate{});
+  }
+
+  return optional<monostate>(nullopt);
+}
+#else
+template <class Opt, class F,
+          class Ret = decltype(detail::invoke(std::declval<F>(),
+                                              *std::declval<Opt>())),
+          detail::enable_if_t<!std::is_void<Ret>::value> * = nullptr>
+
+constexpr auto optional_map_impl(Opt &&opt, F &&f) -> optional<Ret> {
+  return opt.has_value()
+             ? detail::invoke(std::forward<F>(f), *std::forward<Opt>(opt))
+             : optional<Ret>(nullopt);
+}
+
+template <class Opt, class F,
+          class Ret = decltype(detail::invoke(std::declval<F>(),
+                                              *std::declval<Opt>())),
+          detail::enable_if_t<std::is_void<Ret>::value> * = nullptr>
+
+auto optional_map_impl(Opt &&opt, F &&f) -> optional<monostate> {
+  if (opt.has_value()) {
+    detail::invoke(std::forward<F>(f), *std::forward<Opt>(opt));
+    return monostate{};
+  }
+
+  return nullopt;
+}
+#endif
+} // namespace detail
+
+/// Specialization for when `T` is a reference. `optional<T&>` acts similarly
+/// to a `T*`, but provides more operations and shows intent more clearly.
+template <class T> class optional<T &> {
+public:
+// The different versions for C++14 and 11 are needed because deduced return
+// types are not SFINAE-safe. This provides better support for things like
+// generic lambdas. C.f.
+// http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2017/p0826r0.html
+#if defined(TL_OPTIONAL_CXX14) && !defined(TL_OPTIONAL_GCC49) &&               \
+    !defined(TL_OPTIONAL_GCC54) && !defined(TL_OPTIONAL_GCC55)
+
+  /// Carries out some operation which returns an optional on the stored
+  /// object if there is one.
+  template <class F> TL_OPTIONAL_11_CONSTEXPR auto and_then(F &&f) & {
+    using result = detail::invoke_result_t<F, T &>;
+    static_assert(detail::is_optional<result>::value,
+                  "F must return an optional");
+
+    return has_value() ? detail::invoke(std::forward<F>(f), **this)
+                       : result(nullopt);
+  }
+
+  template <class F> TL_OPTIONAL_11_CONSTEXPR auto and_then(F &&f) && {
+    using result = detail::invoke_result_t<F, T &>;
+    static_assert(detail::is_optional<result>::value,
+                  "F must return an optional");
+
+    return has_value() ? detail::invoke(std::forward<F>(f), **this)
+                       : result(nullopt);
+  }
+
+  template <class F> constexpr auto and_then(F &&f) const & {
+    using result = detail::invoke_result_t<F, const T &>;
+    static_assert(detail::is_optional<result>::value,
+                  "F must return an optional");
+
+    return has_value() ? detail::invoke(std::forward<F>(f), **this)
+                       : result(nullopt);
+  }
+
+#ifndef TL_OPTIONAL_NO_CONSTRR
+  template <class F> constexpr auto and_then(F &&f) const && {
+    using result = detail::invoke_result_t<F, const T &>;
+    static_assert(detail::is_optional<result>::value,
+                  "F must return an optional");
+
+    return has_value() ? detail::invoke(std::forward<F>(f), **this)
+                       : result(nullopt);
+  }
+#endif
+#else
+  /// Carries out some operation which returns an optional on the stored
+  /// object if there is one.
+  template <class F>
+  TL_OPTIONAL_11_CONSTEXPR detail::invoke_result_t<F, T &> and_then(F &&f) & {
+    using result = detail::invoke_result_t<F, T &>;
+    static_assert(detail::is_optional<result>::value,
+                  "F must return an optional");
+
+    return has_value() ? detail::invoke(std::forward<F>(f), **this)
+                       : result(nullopt);
+  }
+
+  template <class F>
+  TL_OPTIONAL_11_CONSTEXPR detail::invoke_result_t<F, T &> and_then(F &&f) && {
+    using result = detail::invoke_result_t<F, T &>;
+    static_assert(detail::is_optional<result>::value,
+                  "F must return an optional");
+
+    return has_value() ? detail::invoke(std::forward<F>(f), **this)
+                       : result(nullopt);
+  }
+
+  template <class F>
+  constexpr detail::invoke_result_t<F, const T &> and_then(F &&f) const & {
+    using result = detail::invoke_result_t<F, const T &>;
+    static_assert(detail::is_optional<result>::value,
+                  "F must return an optional");
+
+    return has_value() ? detail::invoke(std::forward<F>(f), **this)
+                       : result(nullopt);
+  }
+
+#ifndef TL_OPTIONAL_NO_CONSTRR
+  template <class F>
+  constexpr detail::invoke_result_t<F, const T &> and_then(F &&f) const && {
+    using result = detail::invoke_result_t<F, const T &>;
+    static_assert(detail::is_optional<result>::value,
+                  "F must return an optional");
+
+    return has_value() ? detail::invoke(std::forward<F>(f), **this)
+                       : result(nullopt);
+  }
+#endif
+#endif
+
+#if defined(TL_OPTIONAL_CXX14) && !defined(TL_OPTIONAL_GCC49) &&               \
+    !defined(TL_OPTIONAL_GCC54) && !defined(TL_OPTIONAL_GCC55)
+  /// Carries out some operation on the stored object if there is one.
+  template <class F> TL_OPTIONAL_11_CONSTEXPR auto map(F &&f) & {
+    return detail::optional_map_impl(*this, std::forward<F>(f));
+  }
+
+  template <class F> TL_OPTIONAL_11_CONSTEXPR auto map(F &&f) && {
+    return detail::optional_map_impl(std::move(*this), std::forward<F>(f));
+  }
+
+  template <class F> constexpr auto map(F &&f) const & {
+    return detail::optional_map_impl(*this, std::forward<F>(f));
+  }
+
+  template <class F> constexpr auto map(F &&f) const && {
+    return detail::optional_map_impl(std::move(*this), std::forward<F>(f));
+  }
+#else
+  /// Carries out some operation on the stored object if there is one.
+  template <class F>
+  TL_OPTIONAL_11_CONSTEXPR decltype(detail::optional_map_impl(std::declval<optional &>(),
+                                                     std::declval<F &&>()))
+  map(F &&f) & {
+    return detail::optional_map_impl(*this, std::forward<F>(f));
+  }
+
+  template <class F>
+  TL_OPTIONAL_11_CONSTEXPR decltype(detail::optional_map_impl(std::declval<optional &&>(),
+                                                     std::declval<F &&>()))
+  map(F &&f) && {
+    return detail::optional_map_impl(std::move(*this), std::forward<F>(f));
+  }
+
+  template <class F>
+  constexpr decltype(detail::optional_map_impl(std::declval<const optional &>(),
+                                      std::declval<F &&>()))
+  map(F &&f) const & {
+    return detail::optional_map_impl(*this, std::forward<F>(f));
+  }
+
+#ifndef TL_OPTIONAL_NO_CONSTRR
+  template <class F>
+  constexpr decltype(detail::optional_map_impl(std::declval<const optional &&>(),
+                                      std::declval<F &&>()))
+  map(F &&f) const && {
+    return detail::optional_map_impl(std::move(*this), std::forward<F>(f));
+  }
+#endif
+#endif
+
+#if defined(TL_OPTIONAL_CXX14) && !defined(TL_OPTIONAL_GCC49) &&               \
+    !defined(TL_OPTIONAL_GCC54) && !defined(TL_OPTIONAL_GCC55)
+  /// Carries out some operation on the stored object if there is one.
+  template <class F> TL_OPTIONAL_11_CONSTEXPR auto transform(F&& f) & {
+    return detail::optional_map_impl(*this, std::forward<F>(f));
+  }
+
+  template <class F> TL_OPTIONAL_11_CONSTEXPR auto transform(F&& f) && {
+    return detail::optional_map_impl(std::move(*this), std::forward<F>(f));
+  }
+
+  template <class F> constexpr auto transform(F&& f) const & {
+    return detail::optional_map_impl(*this, std::forward<F>(f));
+  }
+
+  template <class F> constexpr auto transform(F&& f) const && {
+    return detail::optional_map_impl(std::move(*this), std::forward<F>(f));
+  }
+#else
+  /// Carries out some operation on the stored object if there is one.
+  template <class F>
+  TL_OPTIONAL_11_CONSTEXPR decltype(detail::optional_map_impl(std::declval<optional&>(),
+    std::declval<F&&>()))
+    transform(F&& f) & {
+    return detail::optional_map_impl(*this, std::forward<F>(f));
+  }
+
+  /// \group map
+  /// \synopsis template <class F> auto transform(F &&f) &&;
+  template <class F>
+  TL_OPTIONAL_11_CONSTEXPR decltype(detail::optional_map_impl(std::declval<optional&&>(),
+    std::declval<F&&>()))
+    transform(F&& f) && {
+    return detail::optional_map_impl(std::move(*this), std::forward<F>(f));
+  }
+
+  template <class F>
+  constexpr decltype(detail::optional_map_impl(std::declval<const optional&>(),
+    std::declval<F&&>()))
+    transform(F&& f) const & {
+    return detail::optional_map_impl(*this, std::forward<F>(f));
+  }
+
+#ifndef TL_OPTIONAL_NO_CONSTRR
+  template <class F>
+  constexpr decltype(detail::optional_map_impl(std::declval<const optional&&>(),
+    std::declval<F&&>()))
+    transform(F&& f) const && {
+    return detail::optional_map_impl(std::move(*this), std::forward<F>(f));
+  }
+#endif
+#endif
+
+  /// Calls `f` if the optional is empty
+  template <class F, detail::enable_if_ret_void<F> * = nullptr>
+  optional<T> TL_OPTIONAL_11_CONSTEXPR or_else(F &&f) & {
+    if (has_value())
+      return *this;
+
+    std::forward<F>(f)();
+    return nullopt;
+  }
+
+  template <class F, detail::disable_if_ret_void<F> * = nullptr>
+  optional<T> TL_OPTIONAL_11_CONSTEXPR or_else(F &&f) & {
+    return has_value() ? *this : std::forward<F>(f)();
+  }
+
+  template <class F, detail::enable_if_ret_void<F> * = nullptr>
+  optional<T> or_else(F &&f) && {
+    if (has_value())
+      return std::move(*this);
+
+    std::forward<F>(f)();
+    return nullopt;
+  }
+
+  template <class F, detail::disable_if_ret_void<F> * = nullptr>
+  optional<T> TL_OPTIONAL_11_CONSTEXPR or_else(F &&f) && {
+    return has_value() ? std::move(*this) : std::forward<F>(f)();
+  }
+
+  template <class F, detail::enable_if_ret_void<F> * = nullptr>
+  optional<T> or_else(F &&f) const & {
+    if (has_value())
+      return *this;
+
+    std::forward<F>(f)();
+    return nullopt;
+  }
+
+  template <class F, detail::disable_if_ret_void<F> * = nullptr>
+  optional<T> TL_OPTIONAL_11_CONSTEXPR or_else(F &&f) const & {
+    return has_value() ? *this : std::forward<F>(f)();
+  }
+
+#ifndef TL_OPTIONAL_NO_CONSTRR
+  template <class F, detail::enable_if_ret_void<F> * = nullptr>
+  optional<T> or_else(F &&f) const && {
+    if (has_value())
+      return std::move(*this);
+
+    std::forward<F>(f)();
+    return nullopt;
+  }
+
+  template <class F, detail::disable_if_ret_void<F> * = nullptr>
+  optional<T> or_else(F &&f) const && {
+    return has_value() ? std::move(*this) : std::forward<F>(f)();
+  }
+#endif
+
+  /// Maps the stored value with `f` if there is one, otherwise returns `u`
+  template <class F, class U> U map_or(F &&f, U &&u) & {
+    return has_value() ? detail::invoke(std::forward<F>(f), **this)
+                       : std::forward<U>(u);
+  }
+
+  template <class F, class U> U map_or(F &&f, U &&u) && {
+    return has_value() ? detail::invoke(std::forward<F>(f), std::move(**this))
+                       : std::forward<U>(u);
+  }
+
+  template <class F, class U> U map_or(F &&f, U &&u) const & {
+    return has_value() ? detail::invoke(std::forward<F>(f), **this)
+                       : std::forward<U>(u);
+  }
+
+#ifndef TL_OPTIONAL_NO_CONSTRR
+  template <class F, class U> U map_or(F &&f, U &&u) const && {
+    return has_value() ? detail::invoke(std::forward<F>(f), std::move(**this))
+                       : std::forward<U>(u);
+  }
+#endif
+
+  /// Maps the stored value with `f` if there is one, otherwise calls
+  /// `u` and returns the result.
+  template <class F, class U>
+  detail::invoke_result_t<U> map_or_else(F &&f, U &&u) & {
+    return has_value() ? detail::invoke(std::forward<F>(f), **this)
+                       : std::forward<U>(u)();
+  }
+
+  template <class F, class U>
+  detail::invoke_result_t<U> map_or_else(F &&f, U &&u) && {
+    return has_value() ? detail::invoke(std::forward<F>(f), std::move(**this))
+                       : std::forward<U>(u)();
+  }
+
+  template <class F, class U>
+  detail::invoke_result_t<U> map_or_else(F &&f, U &&u) const & {
+    return has_value() ? detail::invoke(std::forward<F>(f), **this)
+                       : std::forward<U>(u)();
+  }
+
+#ifndef TL_OPTIONAL_NO_CONSTRR
+  template <class F, class U>
+  detail::invoke_result_t<U> map_or_else(F &&f, U &&u) const && {
+    return has_value() ? detail::invoke(std::forward<F>(f), std::move(**this))
+                       : std::forward<U>(u)();
+  }
+#endif
+
+  /// Returns `u` if `*this` has a value, otherwise an empty optional.
+  template <class U>
+  constexpr optional<typename std::decay<U>::type> conjunction(U &&u) const {
+    using result = optional<detail::decay_t<U>>;
+    return has_value() ? result{u} : result{nullopt};
+  }
+
+  /// Returns `rhs` if `*this` is empty, otherwise the current value.
+  TL_OPTIONAL_11_CONSTEXPR optional disjunction(const optional &rhs) & {
+    return has_value() ? *this : rhs;
+  }
+
+  constexpr optional disjunction(const optional &rhs) const & {
+    return has_value() ? *this : rhs;
+  }
+
+  TL_OPTIONAL_11_CONSTEXPR optional disjunction(const optional &rhs) && {
+    return has_value() ? std::move(*this) : rhs;
+  }
+
+#ifndef TL_OPTIONAL_NO_CONSTRR
+  constexpr optional disjunction(const optional &rhs) const && {
+    return has_value() ? std::move(*this) : rhs;
+  }
+#endif
+
+  TL_OPTIONAL_11_CONSTEXPR optional disjunction(optional &&rhs) & {
+    return has_value() ? *this : std::move(rhs);
+  }
+
+  constexpr optional disjunction(optional &&rhs) const & {
+    return has_value() ? *this : std::move(rhs);
+  }
+
+  TL_OPTIONAL_11_CONSTEXPR optional disjunction(optional &&rhs) && {
+    return has_value() ? std::move(*this) : std::move(rhs);
+  }
+
+#ifndef TL_OPTIONAL_NO_CONSTRR
+  constexpr optional disjunction(optional &&rhs) const && {
+    return has_value() ? std::move(*this) : std::move(rhs);
+  }
+#endif
+
+  /// Takes the value out of the optional, leaving it empty
+  optional take() {
+    optional ret = std::move(*this);
+    reset();
+    return ret;
+  }
+
+  using value_type = T &;
+
+  /// Constructs an optional that does not contain a value.
+  constexpr optional() noexcept : m_value(nullptr) {}
+
+  constexpr optional(nullopt_t) noexcept : m_value(nullptr) {}
+
+  /// Copy constructor
+  ///
+  /// If `rhs` contains a value, the stored value is direct-initialized with
+  /// it. Otherwise, the constructed optional is empty.
+  TL_OPTIONAL_11_CONSTEXPR optional(const optional &rhs) noexcept = default;
+
+  /// Move constructor
+  ///
+  /// If `rhs` contains a value, the stored value is direct-initialized with
+  /// it. Otherwise, the constructed optional is empty.
+  TL_OPTIONAL_11_CONSTEXPR optional(optional &&rhs) = default;
+
+  /// Constructs the stored value with `u`.
+  template <class U = T,
+            detail::enable_if_t<!detail::is_optional<detail::decay_t<U>>::value>
+                * = nullptr>
+  constexpr optional(U &&u)  noexcept : m_value(std::addressof(u)) {
+    static_assert(std::is_lvalue_reference<U>::value, "U must be an lvalue");
+  }
+
+  template <class U>
+  constexpr explicit optional(const optional<U> &rhs) noexcept : optional(*rhs) {}
+
+  /// No-op
+  ~optional() = default;
+
+  /// Assignment to empty.
+  ///
+  /// Destroys the current value if there is one.
+  optional &operator=(nullopt_t) noexcept {
+    m_value = nullptr;
+    return *this;
+  }
+
+  /// Copy assignment.
+  ///
+  /// Rebinds this optional to the referee of `rhs` if there is one. Otherwise
+  /// resets the stored value in `*this`.
+  optional &operator=(const optional &rhs) = default;
+
+  /// Rebinds this optional to `u`.
+  template <class U = T,
+            detail::enable_if_t<!detail::is_optional<detail::decay_t<U>>::value>
+                * = nullptr>
+  optional &operator=(U &&u) {
+    static_assert(std::is_lvalue_reference<U>::value, "U must be an lvalue");
+    m_value = std::addressof(u);
+    return *this;
+  }
+
+  /// Converting copy assignment operator.
+  ///
+  /// Rebinds this optional to the referee of `rhs` if there is one. Otherwise
+  /// resets the stored value in `*this`.
+  template <class U> optional &operator=(const optional<U> &rhs) noexcept {
+    m_value = std::addressof(rhs.value());
+    return *this;
+  }
+
+  /// Rebinds this optional to `u`.
+  template <class U = T,
+            detail::enable_if_t<!detail::is_optional<detail::decay_t<U>>::value>
+                * = nullptr>
+  optional &emplace(U &&u) noexcept {
+    return *this = std::forward<U>(u);
+  }
+
+  void swap(optional &rhs) noexcept { std::swap(m_value, rhs.m_value); }
+
+  /// Returns a pointer to the stored value
+  constexpr const T *operator->() const noexcept { return m_value; }
+
+  TL_OPTIONAL_11_CONSTEXPR T *operator->() noexcept { return m_value; }
+
+  /// Returns the stored value
+  TL_OPTIONAL_11_CONSTEXPR T &operator*() noexcept { return *m_value; }
+
+  constexpr const T &operator*() const noexcept { return *m_value; }
+
+  constexpr bool has_value() const noexcept { return m_value != nullptr; }
+
+  constexpr explicit operator bool() const noexcept {
+    return m_value != nullptr;
+  }
+
+  /// Returns the contained value if there is one, otherwise throws bad_optional_access
+  TL_OPTIONAL_11_CONSTEXPR T &value() {
+    if (has_value())
+      return *m_value;
+    throw bad_optional_access();
+  }
+  TL_OPTIONAL_11_CONSTEXPR const T &value() const {
+    if (has_value())
+      return *m_value;
+    throw bad_optional_access();
+  }
+
+  /// Returns the stored value if there is one, otherwise returns `u`
+  template <class U> constexpr T value_or(U &&u) const & noexcept {
+    static_assert(std::is_copy_constructible<T>::value &&
+                      std::is_convertible<U &&, T>::value,
+                  "T must be copy constructible and convertible from U");
+    return has_value() ? **this : static_cast<T>(std::forward<U>(u));
+  }
+
+  /// \group value_or
+  template <class U> TL_OPTIONAL_11_CONSTEXPR T value_or(U &&u) && noexcept {
+    static_assert(std::is_move_constructible<T>::value &&
+                      std::is_convertible<U &&, T>::value,
+                  "T must be move constructible and convertible from U");
+    return has_value() ? **this : static_cast<T>(std::forward<U>(u));
+  }
+
+  /// Destroys the stored value if one exists, making the optional empty
+  void reset() noexcept { m_value = nullptr; }
+
+private:
+  T *m_value;
+}; // namespace tl
+
+
+
+} // namespace tl
+
+namespace std {
+// TODO SFINAE
+template <class T> struct hash<tl::optional<T>> {
+  ::std::size_t operator()(const tl::optional<T> &o) const {
+    if (!o.has_value())
+      return 0;
+
+    return std::hash<tl::detail::remove_const_t<T>>()(*o);
+  }
+};
+} // namespace std
+
+#endif

paddlespeech/audio/src/pybind/pybind.cpp

 //Copyright (c) 2017 Facebook Inc. (Soumith Chintala), 
 //All rights reserved.
 
-#include "pybind/sox/io.h"
+#include "paddlespeech/audio/src/pybind/sox/io.h"
 
 PYBIND11_MODULE(_paddleaudio, m) {
   m.def("get_info_file", &paddleaudio::sox_io::get_info_file,

paddlespeech/audio/src/pybind/sox/io.cpp

 //Copyright (c) 2017 Facebook Inc. (Soumith Chintala), 
 //All rights reserved.
 
-#include "pybind/sox/io.h"
-#include "pybind/sox/utils.h"
+#include "paddlespeech/audio/src/pybind/sox/io.h"
+#include "paddlespeech/audio/src/pybind/sox/utils.h"
 
 using namespace paddleaudio::sox_utils;
 

paddlespeech/audio/src/pybind/sox/io.h

@@ -4,7 +4,7 @@
 #ifndef PADDLEAUDIO_PYBIND_SOX_IO_H
 #define PADDLEAUDIO_PYBIND_SOX_IO_H
 
-#include "pybind/sox/utils.h"
+#include "paddlespeech/audio/src/pybind/sox/utils.h"
 
 namespace paddleaudio {
 namespace sox_io {

paddlespeech/audio/src/pybind/sox/utils.cpp

 //Copyright (c) 2017 Facebook Inc. (Soumith Chintala), 
 //All rights reserved.
 
-#include "pybind/sox/utils.h"
+#include "paddlespeech/audio/src/pybind/sox/utils.h"
 
 #include <sstream>
 

paddlespeech/audio/src/sox/io.cpp

+// #include "sox/effects.h"
+// #include "sox/effects_chain.h"
+#include "sox/io.h"
+#include "sox/types.h"
+#include "sox/utils.h"
+
+using namespace torch::indexing;
+using namespace paddleaudio::sox_utils;
+
+namespace paddleaudio {
+namespace sox_io {
+
+tl::optional<MetaDataTuple> get_info_file(
+    const std::string& path,
+    const tl::optional<std::string>& format) {
+  SoxFormat sf(sox_open_read(
+      path.c_str(),
+      /*signal=*/nullptr,
+      /*encoding=*/nullptr,
+      /*filetype=*/format.has_value() ? format.value().c_str() : nullptr));
+
+  if (static_cast<sox_format_t*>(sf) == nullptr ||
+      sf->encoding.encoding == SOX_ENCODING_UNKNOWN) {
+    return {};
+  }
+
+  return std::forward_as_tuple(
+      static_cast<int64_t>(sf->signal.rate),
+      static_cast<int64_t>(sf->signal.length / sf->signal.channels),
+      static_cast<int64_t>(sf->signal.channels),
+      static_cast<int64_t>(sf->encoding.bits_per_sample),
+      get_encoding(sf->encoding.encoding));
+}
+
+std::vector<std::vector<std::string>> get_effects(
+    const tl::optional<int64_t>& frame_offset,
+    const tl::optional<int64_t>& num_frames) {
+  const auto offset = frame_offset.value_or(0);
+  if (offset < 0) {
+    throw std::runtime_error(
+        "Invalid argument: frame_offset must be non-negative.");
+  }
+  const auto frames = num_frames.value_or(-1);
+  if (frames == 0 || frames < -1) {
+    throw std::runtime_error(
+        "Invalid argument: num_frames must be -1 or greater than 0.");
+  }
+
+  std::vector<std::vector<std::string>> effects;
+  if (frames != -1) {
+    std::ostringstream os_offset, os_frames;
+    os_offset << offset << "s";
+    os_frames << "+" << frames << "s";
+    effects.emplace_back(
+        std::vector<std::string>{"trim", os_offset.str(), os_frames.str()});
+  } else if (offset != 0) {
+    std::ostringstream os_offset;
+    os_offset << offset << "s";
+    effects.emplace_back(std::vector<std::string>{"trim", os_offset.str()});
+  }
+  return effects;
+}
+
+tl::optional<std::tuple<torch::Tensor, int64_t>> load_audio_file(
+    const std::string& path,
+    const tl::optional<int64_t>& frame_offset,
+    const tl::optional<int64_t>& num_frames,
+    tl::optional<bool> normalize,
+    tl::optional<bool> channels_first,
+    const tl::optional<std::string>& format) {
+  auto effects = get_effects(frame_offset, num_frames);
+  return paddleaudio::sox_effects::apply_effects_file(
+      path, effects, normalize, channels_first, format);
+}
+
+void save_audio_file(
+    const std::string& path,
+    torch::Tensor tensor,
+    int64_t sample_rate,
+    bool channels_first,
+    tl::optional<double> compression,
+    tl::optional<std::string> format,
+    tl::optional<std::string> encoding,
+    tl::optional<int64_t> bits_per_sample) {
+  validate_input_tensor(tensor);
+
+  const auto filetype = [&]() {
+    if (format.has_value())
+      return format.value();
+    return get_filetype(path);
+  }();
+
+  if (filetype == "amr-nb") {
+    const auto num_channels = tensor.size(channels_first ? 0 : 1);
+    TORCH_CHECK(
+        num_channels == 1, "amr-nb format only supports single channel audio.");
+  } else if (filetype == "htk") {
+    const auto num_channels = tensor.size(channels_first ? 0 : 1);
+    TORCH_CHECK(
+        num_channels == 1, "htk format only supports single channel audio.");
+  } else if (filetype == "gsm") {
+    const auto num_channels = tensor.size(channels_first ? 0 : 1);
+    TORCH_CHECK(
+        num_channels == 1, "gsm format only supports single channel audio.");
+    TORCH_CHECK(
+        sample_rate == 8000,
+        "gsm format only supports a sampling rate of 8kHz.");
+  }
+  const auto signal_info =
+      get_signalinfo(&tensor, sample_rate, filetype, channels_first);
+  const auto encoding_info = get_encodinginfo_for_save(
+      filetype, tensor.dtype(), compression, encoding, bits_per_sample);
+
+  SoxFormat sf(sox_open_write(
+      path.c_str(),
+      &signal_info,
+      &encoding_info,
+      /*filetype=*/filetype.c_str(),
+      /*oob=*/nullptr,
+      /*overwrite_permitted=*/nullptr));
+
+  if (static_cast<sox_format_t*>(sf) == nullptr) {
+    throw std::runtime_error(
+        "Error saving audio file: failed to open file " + path);
+  }
+
+  paddleaudio::sox_effects_chain::SoxEffectsChain chain(
+      /*input_encoding=*/get_tensor_encodinginfo(tensor.dtype()),
+      /*output_encoding=*/sf->encoding);
+  chain.addInputTensor(&tensor, sample_rate, channels_first);
+  chain.addOutputFile(sf);
+  chain.run();
+}
+
+TORCH_LIBRARY_FRAGMENT(paddleaudio, m) {
+  m.def("paddleaudio::sox_io_get_info", &paddleaudio::sox_io::get_info_file);
+  m.def(
+      "paddleaudio::sox_io_load_audio_file",
+      &paddleaudio::sox_io::load_audio_file);
+  m.def(
+      "paddleaudio::sox_io_save_audio_file",
+      &paddleaudio::sox_io::save_audio_file);
+}
+
+} // namespace sox_io
+} // namespace paddleaudio
\ No newline at end of file

paddlespeech/audio/src/sox/io.h

+
+//Copyright (c) 2017 Facebook Inc. (Soumith Chintala), 
+//All rights reserved.
+
+#ifndef PADDLEAUDIO_SOX_IO_H
+#define PADDLEAUDIO_SOX_IO_H
+
+// #include "sox/utils.h"
+#include "optional/optional.hpp"
+
+namespace paddleaudio {
+namespace sox_io {
+
+auto get_effects(
+    const tl::optional<int64_t>& frame_offset,
+    const tl::optional<int64_t>& num_frames)
+    -> std::vector<std::vector<std::string>>;
+
+using MetaDataTuple =
+    std::tuple<int64_t, int64_t, int64_t, int64_t, std::string>;
+
+tl::optional<MetaDataTuple> get_info_file(
+    const std::string& path,
+    const tl::optional<std::string>& format);
+
+tl::optional<std::tuple<torch::Tensor, int64_t>> load_audio_file(
+    const std::string& path,
+    const tl::optional<int64_t>& frame_offset,
+    const tl::optional<int64_t>& num_frames,
+    tl::optional<bool> normalize,
+    tl::optional<bool> channels_first,
+    const tl::optional<std::string>& format);
+
+void save_audio_file(
+    const std::string& path,
+    torch::Tensor tensor,
+    int64_t sample_rate,
+    bool channels_first,
+    tl::optional<double> compression,
+    tl::optional<std::string> format,
+    tl::optional<std::string> encoding,
+    tl::optional<int64_t> bits_per_sample);
+
+} // namespace sox_io
+} // namespace paddleaudio
+
+#endif
\ No newline at end of file

paddlespeech/audio/src/utils.cpp

+namespace paddleaudio {
+
+namespace {
+
+bool is_sox_available() {
+#ifdef INCLUDE_SOX
+  return true;
+#else
+  return false;
+#endif
+}
+
+bool is_kaldi_available() {
+#ifdef INCLUDE_KALDI
+  return true;
+#else
+  return false;
+#endif
+}
+
+// It tells whether paddleaudio was compiled with ffmpeg
+// not the runtime availability.
+bool is_ffmpeg_available() {
+#ifdef USE_FFMPEG
+  return true;
+#else
+  return false;
+#endif
+}
+
+} // namespace
+
+} // namespace paddleaudio
\ No newline at end of file

paddlespeech/audio/third_party/CMakeLists.txt

 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fvisibility=hidden")
 
-add_library(libsox INTERFACE)
 if (BUILD_SOX)
   add_subdirectory(sox)
-  target_include_directories(libsox INTERFACE ${SOX_INCLUDE_DIR})
-  target_link_libraries(libsox INTERFACE ${SOX_LIBRARIES})
 endif()
 
 include_directories(

paddlespeech/audio/third_party/sox/CMakeLists.txt

@@ -17,22 +17,24 @@ set(envs
   "CFLAGS=-I${INSTALL_DIR}/include -fvisibility=hidden $ENV{CFLAGS}"
 )
 
-ExternalProject_Add(mad
-  PREFIX ${CMAKE_CURRENT_BINARY_DIR}
-  DOWNLOAD_DIR ${ARCHIVE_DIR}
-  URL https://downloads.sourceforge.net/project/mad/libmad/0.15.1b/libmad-0.15.1b.tar.gz
-  URL_HASH SHA256=bbfac3ed6bfbc2823d3775ebb931087371e142bb0e9bb1bee51a76a6e0078690
-  PATCH_COMMAND patch < ${patch_dir}/libmad.patch && cp ${patch_dir}/config.guess ${patch_dir}/config.sub ${CMAKE_CURRENT_BINARY_DIR}/src/mad/
-  CONFIGURE_COMMAND ${CMAKE_COMMAND} -E env ${envs} ${CMAKE_CURRENT_BINARY_DIR}/src/mad/configure ${COMMON_ARGS}
-  DOWNLOAD_NO_PROGRESS ON
-  LOG_DOWNLOAD ON
-  LOG_UPDATE ON
-  LOG_CONFIGURE ON
-  LOG_BUILD ON
-  LOG_INSTALL ON
-  LOG_MERGED_STDOUTERR ON
-  LOG_OUTPUT_ON_FAILURE ON
-)
+if (BUILD_MAD)
+  ExternalProject_Add(mad
+    PREFIX ${CMAKE_CURRENT_BINARY_DIR}
+    DOWNLOAD_DIR ${ARCHIVE_DIR}
+    URL https://downloads.sourceforge.net/project/mad/libmad/0.15.1b/libmad-0.15.1b.tar.gz
+    URL_HASH SHA256=bbfac3ed6bfbc2823d3775ebb931087371e142bb0e9bb1bee51a76a6e0078690
+    PATCH_COMMAND patch < ${patch_dir}/libmad.patch && cp ${patch_dir}/config.guess ${patch_dir}/config.sub ${CMAKE_CURRENT_BINARY_DIR}/src/mad/
+    CONFIGURE_COMMAND ${CMAKE_COMMAND} -E env ${envs} ${CMAKE_CURRENT_BINARY_DIR}/src/mad/configure ${COMMON_ARGS}
+    DOWNLOAD_NO_PROGRESS ON
+    LOG_DOWNLOAD ON
+    LOG_UPDATE ON
+    LOG_CONFIGURE ON
+    LOG_BUILD ON
+    LOG_INSTALL ON
+    LOG_MERGED_STDOUTERR ON
+    LOG_OUTPUT_ON_FAILURE ON
+  )
+endif (BUILD_MAD)
 
 ExternalProject_Add(amr
   PREFIX ${CMAKE_CURRENT_BINARY_DIR}
@@ -157,13 +159,15 @@ ExternalProject_Add(opusfile
   LOG_OUTPUT_ON_FAILURE ON
 )
 
+# OpenMP is by default compiled against GNU OpenMP, which conflicts with the version of OpenMP that PyTorch uses.
+# See https://github.com/pytorch/audio/pull/1026
+# TODO: Add flags like https://github.com/suphoff/pytorch_parallel_extension_cpp/blob/master/setup.py
 set(SOX_OPTIONS
   --disable-openmp
   --with-amrnb
   --with-amrwb
   --with-flac
   --with-lame
-  --with-mad
   --with-oggvorbis
   --with-opus
   --without-alsa
@@ -187,7 +191,6 @@ set(SOX_LIBRARIES
   ${INSTALL_DIR}/lib/libsox.a
   ${INSTALL_DIR}/lib/libopencore-amrnb.a
   ${INSTALL_DIR}/lib/libopencore-amrwb.a
-  ${INSTALL_DIR}/lib/libmad.a
   ${INSTALL_DIR}/lib/libmp3lame.a
   ${INSTALL_DIR}/lib/libFLAC.a
   ${INSTALL_DIR}/lib/libopusfile.a
@@ -198,9 +201,37 @@ set(SOX_LIBRARIES
   ${INSTALL_DIR}/lib/libogg.a
   )
 
+set(sox_depends
+  ogg flac vorbis opusfile lame amr
+  )
+
+if (BUILD_MAD)
+  list(
+    APPEND
+    SOX_OPTIONS
+    --with-mad
+    )
+  list(
+    APPEND
+    SOX_LIBRARIES
+    ${INSTALL_DIR}/lib/libmad.a
+    )
+  list(
+    APPEND
+    sox_depends
+    mad
+    )
+else ()
+  list(
+    APPEND
+    SOX_OPTIONS
+    --without-mad
+    )  
+endif (BUILD_MAD)
+
 ExternalProject_Add(sox
   PREFIX ${CMAKE_CURRENT_BINARY_DIR}
-  DEPENDS ogg flac vorbis opusfile lame mad amr
+  DEPENDS ${sox_depends}
   DOWNLOAD_DIR ${ARCHIVE_DIR}
   URL https://downloads.sourceforge.net/project/sox/sox/14.4.2/sox-14.4.2.tar.bz2
   URL_HASH SHA256=81a6956d4330e75b5827316e44ae381e6f1e8928003c6aa45896da9041ea149c
@@ -217,6 +248,7 @@ ExternalProject_Add(sox
   LOG_OUTPUT_ON_FAILURE ON
 )
 
+add_library(libsox INTERFACE)
 add_dependencies(libsox sox)
-set(SOX_INCLUDE_DIR ${INSTALL_DIR}/include PARENT_SCOPE)
-set(SOX_LIBRARIES ${SOX_LIBRARIES} PARENT_SCOPE)
+target_include_directories(libsox INTERFACE ${INSTALL_DIR}/include)
+target_link_libraries(libsox INTERFACE ${SOX_LIBRARIES})
\ No newline at end of file

setup.py

@@ -18,7 +18,11 @@ import os
 import subprocess as sp
 import sys
 from pathlib import Path
+from typing import Union
+from typing import Tuple
+from typing import List
 
+import distutils.command.clean
 from setuptools import Command
 from setuptools import find_packages
 from setuptools import setup
@@ -26,7 +30,9 @@ from setuptools.command.develop import develop
 from setuptools.command.install import install
 from setuptools.command.test import test
 
-HERE = Path(os.path.abspath(os.path.dirname(__file__)))
+from tools import setup_helpers
+
+HERE = Path(__file__).parent.resolve()
 
 VERSION = '0.0.0'
 COMMITID = 'none'
@@ -114,9 +120,15 @@ def check_call(cmd: str, shell=False, executable=None):
         raise e
 
 
-def check_output(cmd: str, shell=False):
+def check_output(cmd: Union[str, List[str], Tuple[str]], shell=False):
     try:
-        out_bytes = sp.check_output(cmd.split())
+
+        if isinstance(cmd, (list, tuple)):
+            cmds = cmd
+        else:
+            cmds = cmd.split()
+        out_bytes = sp.check_output(cmds)
+
     except sp.CalledProcessError as e:
         out_bytes = e.output  # Output generated before error
         code = e.returncode  # Return code
@@ -216,121 +228,135 @@ class UploadCommand(Command):
 
 
 ################################# Version ##################################
-def write_version_py(filename='paddlespeech/__init__.py'):
-    import paddlespeech
-    if hasattr(paddlespeech,
-               "__version__") and paddlespeech.__version__ == VERSION:
-        return
-    with open(filename, "a") as f:
-        out_str = f"\n__version__ = '{VERSION}'\n"
-        print(out_str)
-        f.write(f"\n__version__ = '{VERSION}'\n")
-
-    COMMITID = check_output("git rev-parse HEAD")
-    with open(filename, 'a') as f:
-        out_str = f"\n__commit__ = '{COMMITID}'\n"
-        print(out_str)
-        f.write(f"\n__commit__ = '{COMMITID}'\n")
-
-    print(f"{inspect.currentframe().f_code.co_name} done")
-
-
-def remove_version_py(filename='paddlespeech/__init__.py'):
-    with open(filename, "r") as f:
-        lines = f.readlines()
-    with open(filename, "w") as f:
-        for line in lines:
-            if "__version__" in line or "__commit__" in line:
-                continue
-            f.write(line)
-    print(f"{inspect.currentframe().f_code.co_name} done")
+def _get_version(sha):
+    version = VERSION
+    if os.getenv("BUILD_VERSION"):
+        version = os.getenv("BUILD_VERSION")
+    elif sha is not None:
+        version += "+" + sha[:7]
+    return version
 
 
-@contextlib.contextmanager
-def version_info():
-    write_version_py()
-    yield
-    remove_version_py()
+def _make_version_file(version, sha):
+    sha = "Unknown" if sha is None else sha
+    version_path = HERE / "paddlespeech" / "version.py"
+    with open(version_path, "w") as f:
+        f.write(f"__version__ = '{version}'\n")
+        f.write(f"__commit__ = '{sha}'\n")
 
 
 ################################# Steup ##################################
-setup_info = dict(
-    # Metadata
-    name='paddlespeech',
-    version=VERSION,
-    author='PaddlePaddle Speech and Language Team',
-    author_email='paddlesl@baidu.com',
-    url='https://github.com/PaddlePaddle/PaddleSpeech',
-    license='Apache 2.0',
-    description='Speech tools and models based on Paddlepaddle',
-    long_description=read("README.md"),
-    long_description_content_type="text/markdown",
-    keywords=[
-        "speech",
-        "asr",
-        "tts",
-        "streaming asr"
-        "streaming tts"
-        "audio process"
-        "speaker verfication",
-        "speech classfication",
-        "text frontend",
-        "MFA",
-        "paddlepaddle",
-        "beam search",
-        "ctcdecoder",
-        "deepspeech2",
-        "transformer",
-        "conformer",
-        "fastspeech",
-        "vocoder",
-        "pwgan",
-        "melgan",
-        "mb-melgan",
-        "hifigan",
-        "gan",
-        "wfst decoder",
-    ],
-    python_requires='>=3.7',
-    install_requires=requirements["install"],
-    extras_require={
-        'develop':
-        requirements["develop"],
-        'doc': [
-            "sphinx", "sphinx-rtd-theme", "numpydoc", "myst_parser",
-            "recommonmark>=0.5.0", "sphinx-markdown-tables", "sphinx-autobuild"
-        ],
-        'test': ['nose', 'torchaudio==0.10.2'],
-    },
-    cmdclass={
-        'develop': DevelopCommand,
-        'install': InstallCommand,
-        'upload': UploadCommand,
-        'test': TestCommand,
-    },
-
-    # Package info
-    packages=find_packages(include=('paddlespeech*')),
-    zip_safe=True,
-    classifiers=[
-        'Development Status :: 5 - Production/Stable',
-        'Intended Audience :: Developers',
-        'Intended Audience :: Science/Research',
-        'Topic :: Scientific/Engineering :: Artificial Intelligence',
-        'License :: OSI Approved :: Apache Software License',
-        'Programming Language :: Python',
-        'Programming Language :: Python :: 3',
-        'Programming Language :: Python :: 3.7',
-        'Programming Language :: Python :: 3.8',
-        'Programming Language :: Python :: 3.9',
-    ],
-    entry_points={
-        'console_scripts': [
-            'paddlespeech=paddlespeech.cli.entry:_execute',
-            'paddlespeech_server=paddlespeech.server.entry:server_execute',
-            'paddlespeech_client=paddlespeech.server.entry:client_execute'
+class clean(distutils.command.clean.clean):
+    def run(self):
+        # Run default behavior first
+        distutils.command.clean.clean.run(self)
+
+        # Remove torchaudio extension
+        for path in (ROOT_DIR / "paddlespeech").glob("**/*.so"):
+            print(f"removing '{path}'")
+            path.unlink()
+        # Remove build directory
+        build_dirs = [
+            ROOT_DIR / "build",
         ]
-    })
+        for path in build_dirs:
+            if path.exists():
+                print(f"removing '{path}' (and everything under it)")
+                shutil.rmtree(str(path), ignore_errors=True)
+
+def main():
+    sha = check_output(["git", "rev-parse", "HEAD"]) # commit id
+    branch = check_output(["git", "rev-parse", "--abbrev-ref", "HEAD"])
+    tag = check_output(["git", "describe", "--tags", "--exact-match", "@"])
+    print("-- Git branch:", branch)
+    print("-- Git SHA:", sha)
+    print("-- Git tag:", tag)
+    version = _get_version(sha)
+    print("-- Building version", version)
+    _make_version_file(version, sha)
+
+    setup_info = dict(
+        # Metadata
+        name='paddlespeech',
+        version=VERSION,
+        author='PaddlePaddle Speech and Language Team',
+        author_email='paddlesl@baidu.com',
+        url='https://github.com/PaddlePaddle/PaddleSpeech',
+        license='Apache 2.0',
+        description='Speech tools and models based on Paddlepaddle',
+        long_description=read("README.md"),
+        long_description_content_type="text/markdown",
+        keywords=[
+            "speech",
+            "asr",
+            "tts",
+            "streaming asr"
+            "streaming tts"
+            "audio process"
+            "speaker verfication",
+            "speech classfication",
+            "text frontend",
+            "MFA",
+            "paddlepaddle",
+            "beam search",
+            "ctcdecoder",
+            "deepspeech2",
+            "transformer",
+            "conformer",
+            "fastspeech",
+            "vocoder",
+            "pwgan",
+            "melgan",
+            "mb-melgan",
+            "hifigan",
+            "gan",
+            "wfst decoder",
+        ],
+        python_requires='>=3.7',
+        install_requires=requirements["install"],
+        extras_require={
+            'develop':
+            requirements["develop"],
+            'doc': [
+                "sphinx", "sphinx-rtd-theme", "numpydoc", "myst_parser",
+                "recommonmark>=0.5.0", "sphinx-markdown-tables", "sphinx-autobuild"
+            ],
+            'test': ['nose', 'torchaudio==0.10.2'],
+        },
+        cmdclass={
+            'develop': DevelopCommand,
+            'install': InstallCommand,
+            'upload': UploadCommand,
+            'test': TestCommand,
+            "build_ext": setup_helpers.CMakeBuild,
+            "clean": clean,
+        },
+
+        # Package info
+        packages=find_packages(include=('paddlespeech*')),
+        ext_modules=setup_helpers.get_ext_modules(),
+        zip_safe=True,
+        classifiers=[
+            'Development Status :: 5 - Production/Stable',
+            'Intended Audience :: Developers',
+            'Intended Audience :: Science/Research',
+            'Topic :: Scientific/Engineering :: Artificial Intelligence',
+            'License :: OSI Approved :: Apache Software License',
+            'Programming Language :: Python',
+            'Programming Language :: Python :: 3',
+            'Programming Language :: Python :: 3.7',
+            'Programming Language :: Python :: 3.8',
+            'Programming Language :: Python :: 3.9',
+        ],
+        entry_points={
+            'console_scripts': [
+                'paddlespeech=paddlespeech.cli.entry:_execute',
+                'paddlespeech_server=paddlespeech.server.entry:server_execute',
+                'paddlespeech_client=paddlespeech.server.entry:client_execute'
+            ]
+        })
 
-with version_info():
     setup(**setup_info)
+
+if __name__ == '__main__':
+    main()
\ No newline at end of file

tools/setup_helpers/__init__.py

+from .extension import *
\ No newline at end of file

tools/setup_helpers/extension.py

+import distutils.sysconfig
+import os
+import platform
+import subprocess
+from pathlib import Path
+
+from setuptools import Extension
+from setuptools.command.build_ext import build_ext
+
+__all__ = [
+    "get_ext_modules",
+    "CMakeBuild",
+]
+
+_THIS_DIR = Path(__file__).parent.resolve()
+_ROOT_DIR = _THIS_DIR.parent.parent.resolve()
+_PADDLESPEECH_DIR = _ROOT_DIR / "paddlespeech"
+
+
+def _get_build(var, default=False):
+    if var not in os.environ:
+        return default
+
+    val = os.environ.get(var, "0")
+    trues = ["1", "true", "TRUE", "on", "ON", "yes", "YES"]
+    falses = ["0", "false", "FALSE", "off", "OFF", "no", "NO"]
+    if val in trues:
+        return True
+    if val not in falses:
+        print(f"WARNING: Unexpected environment variable value `{var}={val}`. " f"Expected one of {trues + falses}")
+    return False
+
+
+_BUILD_SOX = False if platform.system() == "Windows" else _get_build("BUILD_SOX", True)
+_BUILD_MAD = _get_build("BUILD_MAD", False)
+# _BUILD_KALDI = False if platform.system() == "Windows" else _get_build("BUILD_KALDI", True)
+# _BUILD_RNNT = _get_build("BUILD_RNNT", True)
+# _BUILD_CTC_DECODER = False if platform.system() == "Windows" else _get_build("BUILD_CTC_DECODER", True)
+# _USE_FFMPEG = _get_build("USE_FFMPEG", False)
+# _USE_ROCM = _get_build("USE_ROCM", torch.cuda.is_available() and torch.version.hip is not None)
+# _USE_CUDA = _get_build("USE_CUDA", torch.cuda.is_available() and torch.version.hip is None)
+# _USE_OPENMP = _get_build("USE_OPENMP", True) and "ATen parallel backend: OpenMP" in torch.__config__.parallel_info()
+_PADDLESPEECH_CUDA_ARCH_LIST = os.environ.get("PADDLESPEECH_CUDA_ARCH_LIST", None)
+
+
+def get_ext_modules():
+    modules = [
+        Extension(name="paddlespeech.audio.lib.libpaddleaudio", sources=[]),
+        Extension(name="paddlespeech.audio._paddleaudio", sources=[]),
+    ]
+    return modules
+
+
+# Based off of
+# https://github.com/pybind/cmake_example/blob/580c5fd29d4651db99d8874714b07c0c49a53f8a/setup.py
+class CMakeBuild(build_ext):
+    def run(self):
+        try:
+            subprocess.check_output(["cmake", "--version"])
+        except OSError:
+            raise RuntimeError("CMake is not available.") from None
+        super().run()
+
+    def build_extension(self, ext):
+        # Since two library files (libpaddleaudio and _paddleaudio) need to be
+        # recognized by setuptools, we instantiate `Extension` twice. (see `get_ext_modules`)
+        # This leads to the situation where this `build_extension` method is called twice.
+        # However, the following `cmake` command will build all of them at the same time,
+        # so, we do not need to perform `cmake` twice.
+        # Therefore we call `cmake` only for `paddleaudio._paddleaudio`.
+        if ext.name != "paddlespeech.audio._paddleaudio":
+            return
+
+        extdir = os.path.abspath(os.path.dirname(self.get_ext_filename(ext.name)))
+
+        # required for auto-detection of auxiliary "native" libs
+        if not extdir.endswith(os.path.sep):
+            extdir += os.path.sep
+
+        cfg = "Debug" if self.debug else "Release"
+
+        cmake_args = [
+            f"-DCMAKE_BUILD_TYPE={cfg}",
+            # f"-DCMAKE_PREFIX_PATH={torch.utils.cmake_prefix_path}",
+            f"-DCMAKE_INSTALL_PREFIX={extdir}",
+            "-DCMAKE_VERBOSE_MAKEFILE=ON",
+            f"-DPython_INCLUDE_DIR={distutils.sysconfig.get_python_inc()}",
+            f"-DBUILD_SOX:BOOL={'ON' if _BUILD_SOX else 'OFF'}",
+            f"-DBUILD_MAD:BOOL={'ON' if _BUILD_MAD else 'OFF'}",
+            # f"-DBUILD_KALDI:BOOL={'ON' if _BUILD_KALDI else 'OFF'}",
+            # f"-DBUILD_RNNT:BOOL={'ON' if _BUILD_RNNT else 'OFF'}",
+            # f"-DBUILD_CTC_DECODER:BOOL={'ON' if _BUILD_CTC_DECODER else 'OFF'}",
+            "-DBUILD_PADDLEAUDIO_PYTHON_EXTENSION:BOOL=ON",
+            # f"-DUSE_ROCM:BOOL={'ON' if _USE_ROCM else 'OFF'}",
+            # f"-DUSE_CUDA:BOOL={'ON' if _USE_CUDA else 'OFF'}",
+            # f"-DUSE_OPENMP:BOOL={'ON' if _USE_OPENMP else 'OFF'}",
+            # f"-DUSE_FFMPEG:BOOL={'ON' if _USE_FFMPEG else 'OFF'}",
+        ]
+        build_args = ["--target", "install"]
+        # Pass CUDA architecture to cmake
+        if _PADDLESPEECH_CUDA_ARCH_LIST is not None:
+            # Convert MAJOR.MINOR[+PTX] list to new style one
+            # defined at https://cmake.org/cmake/help/latest/prop_tgt/CUDA_ARCHITECTURES.html
+            _arches = _PADDLESPEECH_CUDA_ARCH_LIST.replace(".", "").replace(" ", ";").split(";")
+            _arches = [arch[:-4] if arch.endswith("+PTX") else f"{arch}-real" for arch in _arches]
+            cmake_args += [f"-DCMAKE_CUDA_ARCHITECTURES={';'.join(_arches)}"]
+
+        # Default to Ninja
+        if "CMAKE_GENERATOR" not in os.environ or platform.system() == "Windows":
+            cmake_args += ["-GNinja"]
+
+        if platform.system() == "Windows":
+            import sys
+
+            python_version = sys.version_info
+            cmake_args += [
+                "-DCMAKE_C_COMPILER=cl",
+                "-DCMAKE_CXX_COMPILER=cl",
+                f"-DPYTHON_VERSION={python_version.major}.{python_version.minor}",
+            ]
+
+        # Set CMAKE_BUILD_PARALLEL_LEVEL to control the parallel build level
+        # across all generators.
+        if "CMAKE_BUILD_PARALLEL_LEVEL" not in os.environ:
+            # self.parallel is a Python 3 only way to set parallel jobs by hand
+            # using -j in the build_ext call, not supported by pip or PyPA-build.
+            if hasattr(self, "parallel") and self.parallel:
+                # CMake 3.12+ only.
+                build_args += ["-j{}".format(self.parallel)]
+
+        if not os.path.exists(self.build_temp):
+            os.makedirs(self.build_temp)
+
+        print(f"cmake {_ROOT_DIR} {' '.join(cmake_args)}, cwd={self.build_temp}")
+        subprocess.check_call(["cmake", str(_ROOT_DIR)] + cmake_args, cwd=self.build_temp)
+        print(f"cmake --build . {' '.join(build_args)}, cwd={self.build_temp}")
+        subprocess.check_call(["cmake", "--build", "."] + build_args, cwd=self.build_temp)
+
+    def get_ext_filename(self, fullname):
+        ext_filename = super().get_ext_filename(fullname)
+        ext_filename_parts = ext_filename.split(".")
+        without_abi = ext_filename_parts[:-2] + ext_filename_parts[-1:]
+        ext_filename = ".".join(without_abi)
+        return ext_filename