zlib.h 87.6 KB
Newer Older
M
Mark Adler 已提交
1
/* zlib.h -- interface of the 'zlib' general purpose compression library
M
Mark Adler 已提交
2
  version 1.2.8.1, May xxth, 2013
M
Mark Adler 已提交
3

M
Mark Adler 已提交
4
  Copyright (C) 1995-2013 Jean-loup Gailly and Mark Adler
M
Mark Adler 已提交
5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not
     claim that you wrote the original software. If you use this software
     in a product, an acknowledgment in the product documentation would be
     appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be
     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.

  Jean-loup Gailly        Mark Adler
M
Mark Adler 已提交
23
  jloup@gzip.org          madler@alumni.caltech.edu
M
Mark Adler 已提交
24 25 26


  The data format used by the zlib library is described by RFCs (Request for
M
Mark Adler 已提交
27 28
  Comments) 1950 to 1952 in the files http://tools.ietf.org/html/rfc1950
  (zlib format), rfc1951 (deflate format) and rfc1952 (gzip format).
M
Mark Adler 已提交
29
*/
M
Mark Adler 已提交
30

M
Mark Adler 已提交
31 32
#ifndef ZLIB_H
#define ZLIB_H
M
Mark Adler 已提交
33

M
Mark Adler 已提交
34 35
#include "zconf.h"

M
Mark Adler 已提交
36 37 38 39
#ifdef __cplusplus
extern "C" {
#endif

M
Mark Adler 已提交
40 41
#define ZLIB_VERSION "1.2.8.1-motley"
#define ZLIB_VERNUM 0x1281
M
Mark Adler 已提交
42 43
#define ZLIB_VER_MAJOR 1
#define ZLIB_VER_MINOR 2
M
Mark Adler 已提交
44
#define ZLIB_VER_REVISION 8
M
Mark Adler 已提交
45
#define ZLIB_VER_SUBREVISION 1
M
Mark Adler 已提交
46

M
Mark Adler 已提交
47
/*
M
Mark Adler 已提交
48 49 50 51 52
    The 'zlib' compression library provides in-memory compression and
  decompression functions, including integrity checks of the uncompressed data.
  This version of the library supports only one compression method (deflation)
  but other algorithms will be added later and will have the same stream
  interface.
M
Mark Adler 已提交
53

M
Mark Adler 已提交
54 55 56
    Compression can be done in a single step if the buffers are large enough,
  or can be done by repeated calls of the compression function.  In the latter
  case, the application must provide more input and/or consume the output
M
Mark Adler 已提交
57
  (providing more output space) before each call.
M
Mark Adler 已提交
58

M
Mark Adler 已提交
59
    The compressed data format used by default by the in-memory functions is
M
Mark Adler 已提交
60 61
  the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped
  around a deflate stream, which is itself documented in RFC 1951.
M
Mark Adler 已提交
62

M
Mark Adler 已提交
63
    The library also supports reading and writing files in gzip (.gz) format
M
Mark Adler 已提交
64 65 66 67
  with an interface similar to that of stdio using the functions that start
  with "gz".  The gzip format is different from the zlib format.  gzip is a
  gzip wrapper, documented in RFC 1952, wrapped around a deflate stream.

M
Mark Adler 已提交
68
    This library can optionally read and write gzip streams in memory as well.
M
Mark Adler 已提交
69

M
Mark Adler 已提交
70
    The zlib format was designed to be compact and fast for use in memory
M
Mark Adler 已提交
71 72 73 74
  and on communications channels.  The gzip format was designed for single-
  file compression on file systems, has a larger header than zlib to maintain
  directory information, and uses a different, slower check method than zlib.

M
Mark Adler 已提交
75 76 77
    The library does not install any signal handler.  The decoder checks
  the consistency of the compressed data, so the library should never crash
  even in case of corrupted input.
M
Mark Adler 已提交
78 79
*/

M
Mark Adler 已提交
80 81
typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size));
typedef void   (*free_func)  OF((voidpf opaque, voidpf address));
M
Mark Adler 已提交
82 83 84 85

struct internal_state;

typedef struct z_stream_s {
86
    z_const Bytef *next_in;     /* next input byte */
M
Mark Adler 已提交
87
    uInt     avail_in;  /* number of bytes available at next_in */
M
Mark Adler 已提交
88
    uLong    total_in;  /* total number of input bytes read so far */
M
Mark Adler 已提交
89

M
Mark Adler 已提交
90
    Bytef    *next_out; /* next output byte should be put there */
M
Mark Adler 已提交
91
    uInt     avail_out; /* remaining free space at next_out */
M
Mark Adler 已提交
92
    uLong    total_out; /* total number of bytes output so far */
M
Mark Adler 已提交
93

94
    z_const char *msg;  /* last error message, NULL if no error */
M
Mark Adler 已提交
95
    struct internal_state FAR *state; /* not visible by applications */
M
Mark Adler 已提交
96 97 98

    alloc_func zalloc;  /* used to allocate the internal state */
    free_func  zfree;   /* used to free the internal state */
M
Mark Adler 已提交
99
    voidpf     opaque;  /* private data object passed to zalloc and zfree */
M
Mark Adler 已提交
100

M
Mark Adler 已提交
101
    int     data_type;  /* best guess about the data type: binary or text */
M
Mark Adler 已提交
102 103
    uLong   adler;      /* adler32 value of the uncompressed data */
    uLong   reserved;   /* reserved for future use */
M
Mark Adler 已提交
104 105
} z_stream;

M
Mark Adler 已提交
106 107
typedef z_stream FAR *z_streamp;

M
Mark Adler 已提交
108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130
/*
     gzip header information passed to and from zlib routines.  See RFC 1952
  for more details on the meanings of these fields.
*/
typedef struct gz_header_s {
    int     text;       /* true if compressed data believed to be text */
    uLong   time;       /* modification time */
    int     xflags;     /* extra flags (not used when writing a gzip file) */
    int     os;         /* operating system */
    Bytef   *extra;     /* pointer to extra field or Z_NULL if none */
    uInt    extra_len;  /* extra field length (valid if extra != Z_NULL) */
    uInt    extra_max;  /* space at extra (only when reading header) */
    Bytef   *name;      /* pointer to zero-terminated file name or Z_NULL */
    uInt    name_max;   /* space at name (only when reading header) */
    Bytef   *comment;   /* pointer to zero-terminated comment or Z_NULL */
    uInt    comm_max;   /* space at comment (only when reading header) */
    int     hcrc;       /* true if there was or will be a header crc */
    int     done;       /* true when done reading gzip header (not used
                           when writing a gzip file) */
} gz_header;

typedef gz_header FAR *gz_headerp;

M
Mark Adler 已提交
131
/*
M
Mark Adler 已提交
132 133 134 135 136
     The application must update next_in and avail_in when avail_in has dropped
   to zero.  It must update next_out and avail_out when avail_out has dropped
   to zero.  The application must initialize zalloc, zfree and opaque before
   calling the init function.  All other fields are set by the compression
   library and must not be updated by the application.
M
Mark Adler 已提交
137

M
Mark Adler 已提交
138 139 140
     The opaque value provided by the application will be passed as the first
   parameter for calls of zalloc and zfree.  This can be useful for custom
   memory management.  The compression library attaches no meaning to the
M
Mark Adler 已提交
141 142
   opaque value.

M
Mark Adler 已提交
143
     zalloc must return Z_NULL if there is not enough memory for the object.
M
Mark Adler 已提交
144 145 146
   If zlib is used in a multi-threaded application, zalloc and zfree must be
   thread safe.

M
Mark Adler 已提交
147 148 149 150 151 152 153 154 155 156 157 158 159
     On 16-bit systems, the functions zalloc and zfree must be able to allocate
   exactly 65536 bytes, but will not be required to allocate more than this if
   the symbol MAXSEG_64K is defined (see zconf.h).  WARNING: On MSDOS, pointers
   returned by zalloc for objects of exactly 65536 bytes *must* have their
   offset normalized to zero.  The default allocation function provided by this
   library ensures this (see zutil.c).  To reduce memory requirements and avoid
   any allocation of 64K objects, at the expense of compression ratio, compile
   the library with -DMAX_WBITS=14 (see zconf.h).

     The fields total_in and total_out can be used for statistics or progress
   reports.  After compression, total_in holds the total size of the
   uncompressed data and may be saved for use in the decompressor (particularly
   if the decompressor wants to decompress everything in a single step).
M
Mark Adler 已提交
160 161
*/

M
Mark Adler 已提交
162
                        /* constants */
M
Mark Adler 已提交
163 164

#define Z_NO_FLUSH      0
M
Mark Adler 已提交
165
#define Z_PARTIAL_FLUSH 1
M
Mark Adler 已提交
166 167
#define Z_SYNC_FLUSH    2
#define Z_FULL_FLUSH    3
M
Mark Adler 已提交
168
#define Z_FINISH        4
M
Mark Adler 已提交
169
#define Z_BLOCK         5
M
Mark Adler 已提交
170
#define Z_TREES         6
M
Mark Adler 已提交
171
/* Allowed flush values; see deflate() and inflate() below for details */
M
Mark Adler 已提交
172 173 174

#define Z_OK            0
#define Z_STREAM_END    1
M
Mark Adler 已提交
175
#define Z_NEED_DICT     2
M
Mark Adler 已提交
176 177 178 179 180
#define Z_ERRNO        (-1)
#define Z_STREAM_ERROR (-2)
#define Z_DATA_ERROR   (-3)
#define Z_MEM_ERROR    (-4)
#define Z_BUF_ERROR    (-5)
M
Mark Adler 已提交
181
#define Z_VERSION_ERROR (-6)
M
Mark Adler 已提交
182 183
/* Return codes for the compression/decompression functions. Negative values
 * are errors, positive values are used for special but normal events.
M
Mark Adler 已提交
184
 */
M
Mark Adler 已提交
185

M
Mark Adler 已提交
186
#define Z_NO_COMPRESSION         0
M
Mark Adler 已提交
187 188 189 190 191 192 193
#define Z_BEST_SPEED             1
#define Z_BEST_COMPRESSION       9
#define Z_DEFAULT_COMPRESSION  (-1)
/* compression levels */

#define Z_FILTERED            1
#define Z_HUFFMAN_ONLY        2
M
Mark Adler 已提交
194
#define Z_RLE                 3
M
Mark Adler 已提交
195
#define Z_FIXED               4
M
Mark Adler 已提交
196
#define Z_DEFAULT_STRATEGY    0
M
Mark Adler 已提交
197
/* compression strategy; see deflateInit2() below for details */
M
Mark Adler 已提交
198 199

#define Z_BINARY   0
M
Mark Adler 已提交
200 201
#define Z_TEXT     1
#define Z_ASCII    Z_TEXT   /* for compatibility with 1.2.2 and earlier */
M
Mark Adler 已提交
202
#define Z_UNKNOWN  2
M
Mark Adler 已提交
203
/* Possible values of the data_type field (though see inflate()) */
M
Mark Adler 已提交
204 205 206

#define Z_DEFLATED   8
/* The deflate compression method (the only one supported in this version) */
M
Mark Adler 已提交
207 208 209

#define Z_NULL  0  /* for initializing zalloc, zfree, opaque */

M
Mark Adler 已提交
210 211 212
#define zlib_version zlibVersion()
/* for compatibility with versions < 1.0.2 */

M
Mark Adler 已提交
213

M
Mark Adler 已提交
214 215
                        /* basic functions */

M
Mark Adler 已提交
216
ZEXTERN const char * ZEXPORT zlibVersion OF((void));
M
Mark Adler 已提交
217
/* The application can compare zlibVersion and ZLIB_VERSION for consistency.
M
Mark Adler 已提交
218 219 220
   If the first character differs, the library code actually used is not
   compatible with the zlib.h header file used by the application.  This check
   is automatically made by deflateInit and inflateInit.
M
Mark Adler 已提交
221 222
 */

M
Mark Adler 已提交
223
/*
M
Mark Adler 已提交
224
ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level));
M
Mark Adler 已提交
225

M
Mark Adler 已提交
226 227 228 229
     Initializes the internal stream state for compression.  The fields
   zalloc, zfree and opaque must be initialized before by the caller.  If
   zalloc and zfree are set to Z_NULL, deflateInit updates them to use default
   allocation functions.
M
Mark Adler 已提交
230

M
Mark Adler 已提交
231
     The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
M
Mark Adler 已提交
232 233 234 235
   1 gives best speed, 9 gives best compression, 0 gives no compression at all
   (the input data is simply copied a block at a time).  Z_DEFAULT_COMPRESSION
   requests a default compromise between speed and compression (currently
   equivalent to level 6).
M
Mark Adler 已提交
236

M
Mark Adler 已提交
237 238
     deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
   memory, Z_STREAM_ERROR if level is not a valid compression level, or
M
Mark Adler 已提交
239
   Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
M
Mark Adler 已提交
240 241 242
   with the version assumed by the caller (ZLIB_VERSION).  msg is set to null
   if there is no error message.  deflateInit does not perform any compression:
   this will be done by deflate().
M
Mark Adler 已提交
243
*/
M
Mark Adler 已提交
244 245


M
Mark Adler 已提交
246
ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush));
M
Mark Adler 已提交
247
/*
M
Mark Adler 已提交
248
    deflate compresses as much data as possible, and stops when the input
M
Mark Adler 已提交
249 250
  buffer becomes empty or the output buffer becomes full.  It may introduce
  some output latency (reading input without producing any output) except when
M
Mark Adler 已提交
251 252
  forced to flush.

M
Mark Adler 已提交
253
    The detailed semantics are as follows.  deflate performs one or both of the
M
Mark Adler 已提交
254
  following actions:
M
Mark Adler 已提交
255 256

  - Compress more input starting at next_in and update next_in and avail_in
M
Mark Adler 已提交
257
    accordingly.  If not all input can be processed (because there is not
M
Mark Adler 已提交
258 259
    enough room in the output buffer), next_in and avail_in are updated and
    processing will resume at this point for the next call of deflate().
M
Mark Adler 已提交
260 261

  - Provide more output starting at next_out and update next_out and avail_out
M
Mark Adler 已提交
262
    accordingly.  This action is forced if the parameter flush is non zero.
M
Mark Adler 已提交
263
    Forcing flush frequently degrades the compression ratio, so this parameter
M
Mark Adler 已提交
264 265 266 267 268 269 270 271 272 273 274
    should be set only when necessary (in interactive applications).  Some
    output may be provided even if flush is not set.

    Before the call of deflate(), the application should ensure that at least
  one of the actions is possible, by providing more input and/or consuming more
  output, and updating avail_in or avail_out accordingly; avail_out should
  never be zero before the call.  The application can consume the compressed
  output when it wants, for example when the output buffer is full (avail_out
  == 0), or after each call of deflate().  If deflate returns Z_OK and with
  zero avail_out, it must be called again after making room in the output
  buffer because there might be more output pending.
M
Mark Adler 已提交
275

M
Mark Adler 已提交
276
    Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to
M
Mark Adler 已提交
277
  decide how much data to accumulate before producing output, in order to
M
Mark Adler 已提交
278 279
  maximize compression.

M
Mark Adler 已提交
280 281
    If the parameter flush is set to Z_SYNC_FLUSH, all pending output is
  flushed to the output buffer and the output is aligned on a byte boundary, so
M
Mark Adler 已提交
282 283 284 285 286 287 288
  that the decompressor can get all input data available so far.  (In
  particular avail_in is zero after the call if enough output space has been
  provided before the call.) Flushing may degrade compression for some
  compression algorithms and so it should be used only when necessary.  This
  completes the current deflate block and follows it with an empty stored block
  that is three bits plus filler bits to the next byte, followed by four bytes
  (00 00 ff ff).
M
Mark Adler 已提交
289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305

    If flush is set to Z_PARTIAL_FLUSH, all pending output is flushed to the
  output buffer, but the output is not aligned to a byte boundary.  All of the
  input data so far will be available to the decompressor, as for Z_SYNC_FLUSH.
  This completes the current deflate block and follows it with an empty fixed
  codes block that is 10 bits long.  This assures that enough bytes are output
  in order for the decompressor to finish the block before the empty fixed code
  block.

    If flush is set to Z_BLOCK, a deflate block is completed and emitted, as
  for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to
  seven bits of the current block are held to be written as the next byte after
  the next deflate block is completed.  In this case, the decompressor may not
  be provided enough bits at this point in order to complete decompression of
  the data provided so far to the compressor.  It may need to wait for the next
  block to be emitted.  This is for advanced applications that need to control
  the emission of deflate blocks.
M
Mark Adler 已提交
306 307 308 309

    If flush is set to Z_FULL_FLUSH, all output is flushed as with
  Z_SYNC_FLUSH, and the compression state is reset so that decompression can
  restart from this point if previous compressed data has been damaged or if
M
Mark Adler 已提交
310
  random access is desired.  Using Z_FULL_FLUSH too often can seriously degrade
M
Mark Adler 已提交
311
  compression.
M
Mark Adler 已提交
312 313 314 315

    If deflate returns with avail_out == 0, this function must be called again
  with the same value of the flush parameter and more output space (updated
  avail_out), until the flush is complete (deflate returns with non-zero
M
Mark Adler 已提交
316
  avail_out).  In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that
M
Mark Adler 已提交
317 318
  avail_out is greater than six to avoid repeated flush markers due to
  avail_out == 0 on return.
M
Mark Adler 已提交
319

M
Mark Adler 已提交
320
    If the parameter flush is set to Z_FINISH, pending input is processed,
M
Mark Adler 已提交
321 322
  pending output is flushed and deflate returns with Z_STREAM_END if there was
  enough output space; if deflate returns with Z_OK, this function must be
M
Mark Adler 已提交
323
  called again with Z_FINISH and more output space (updated avail_out) but no
M
Mark Adler 已提交
324 325 326
  more input data, until it returns with Z_STREAM_END or an error.  After
  deflate has returned Z_STREAM_END, the only possible operations on the stream
  are deflateReset or deflateEnd.
M
Mark Adler 已提交
327

M
Mark Adler 已提交
328
    Z_FINISH can be used immediately after deflateInit if all the compression
M
Mark Adler 已提交
329
  is to be done in a single step.  In this case, avail_out must be at least the
M
Mark Adler 已提交
330 331 332
  value returned by deflateBound (see below).  Then deflate is guaranteed to
  return Z_STREAM_END.  If not enough output space is provided, deflate will
  not return Z_STREAM_END, and it must be called again as described above.
M
Mark Adler 已提交
333

M
Mark Adler 已提交
334 335 336
    deflate() sets strm->adler to the adler32 checksum of all input read
  so far (that is, total_in bytes).

M
Mark Adler 已提交
337
    deflate() may update strm->data_type if it can make a good guess about
M
Mark Adler 已提交
338 339 340
  the input data type (Z_BINARY or Z_TEXT).  In doubt, the data is considered
  binary.  This field is only for information purposes and does not affect the
  compression algorithm in any manner.
M
Mark Adler 已提交
341

M
Mark Adler 已提交
342 343 344 345
    deflate() returns Z_OK if some progress has been made (more input
  processed or more output produced), Z_STREAM_END if all input has been
  consumed and all output has been produced (only when flush is set to
  Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
M
Mark Adler 已提交
346
  if next_in or next_out was Z_NULL), Z_BUF_ERROR if no progress is possible
M
Mark Adler 已提交
347
  (for example avail_in or avail_out was zero).  Note that Z_BUF_ERROR is not
M
Mark Adler 已提交
348 349
  fatal, and deflate() can be called again with more input and more output
  space to continue compressing.
M
Mark Adler 已提交
350
*/
M
Mark Adler 已提交
351 352


M
Mark Adler 已提交
353
ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm));
M
Mark Adler 已提交
354 355
/*
     All dynamically allocated data structures for this stream are freed.
M
Mark Adler 已提交
356 357
   This function discards any unprocessed input and does not flush any pending
   output.
M
Mark Adler 已提交
358 359

     deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
M
Mark Adler 已提交
360
   stream state was inconsistent, Z_DATA_ERROR if the stream was freed
M
Mark Adler 已提交
361 362
   prematurely (some input or output was discarded).  In the error case, msg
   may be set but then points to a static string (which must not be
M
Mark Adler 已提交
363
   deallocated).
M
Mark Adler 已提交
364 365 366
*/


M
Mark Adler 已提交
367
/*
M
Mark Adler 已提交
368
ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm));
M
Mark Adler 已提交
369

M
Mark Adler 已提交
370
     Initializes the internal stream state for decompression.  The fields
M
Mark Adler 已提交
371
   next_in, avail_in, zalloc, zfree and opaque must be initialized before by
M
Mark Adler 已提交
372 373
   the caller.  If next_in is not Z_NULL and avail_in is large enough (the
   exact value depends on the compression method), inflateInit determines the
M
Mark Adler 已提交
374 375 376 377
   compression method from the zlib header and allocates all data structures
   accordingly; otherwise the allocation will be deferred to the first call of
   inflate.  If zalloc and zfree are set to Z_NULL, inflateInit updates them to
   use default allocation functions.
M
Mark Adler 已提交
378

M
Mark Adler 已提交
379 380
     inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
   memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
M
Mark Adler 已提交
381 382
   version assumed by the caller, or Z_STREAM_ERROR if the parameters are
   invalid, such as a null pointer to the structure.  msg is set to null if
M
Mark Adler 已提交
383
   there is no error message.  inflateInit does not perform any decompression
M
Mark Adler 已提交
384 385
   apart from possibly reading the zlib header if present: actual decompression
   will be done by inflate().  (So next_in and avail_in may be modified, but
M
Mark Adler 已提交
386 387 388
   next_out and avail_out are unused and unchanged.) The current implementation
   of inflateInit() does not process any header information -- that is deferred
   until inflate() is called.
M
Mark Adler 已提交
389 390 391
*/


M
Mark Adler 已提交
392
ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush));
M
Mark Adler 已提交
393
/*
M
Mark Adler 已提交
394
    inflate decompresses as much data as possible, and stops when the input
M
Mark Adler 已提交
395
  buffer becomes empty or the output buffer becomes full.  It may introduce
M
Mark Adler 已提交
396 397
  some output latency (reading input without producing any output) except when
  forced to flush.
M
Mark Adler 已提交
398

M
Mark Adler 已提交
399
  The detailed semantics are as follows.  inflate performs one or both of the
M
Mark Adler 已提交
400
  following actions:
M
Mark Adler 已提交
401 402

  - Decompress more input starting at next_in and update next_in and avail_in
M
Mark Adler 已提交
403 404 405
    accordingly.  If not all input can be processed (because there is not
    enough room in the output buffer), next_in is updated and processing will
    resume at this point for the next call of inflate().
M
Mark Adler 已提交
406 407

  - Provide more output starting at next_out and update next_out and avail_out
M
Mark Adler 已提交
408 409 410 411 412 413 414 415 416 417 418 419
    accordingly.  inflate() provides as much output as possible, until there is
    no more input data or no more space in the output buffer (see below about
    the flush parameter).

    Before the call of inflate(), the application should ensure that at least
  one of the actions is possible, by providing more input and/or consuming more
  output, and updating the next_* and avail_* values accordingly.  The
  application can consume the uncompressed output when it wants, for example
  when the output buffer is full (avail_out == 0), or after each call of
  inflate().  If inflate returns Z_OK and with zero avail_out, it must be
  called again after making room in the output buffer because there might be
  more output pending.
M
Mark Adler 已提交
420

M
Mark Adler 已提交
421
    The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, Z_FINISH,
M
Mark Adler 已提交
422 423 424 425 426 427 428
  Z_BLOCK, or Z_TREES.  Z_SYNC_FLUSH requests that inflate() flush as much
  output as possible to the output buffer.  Z_BLOCK requests that inflate()
  stop if and when it gets to the next deflate block boundary.  When decoding
  the zlib or gzip format, this will cause inflate() to return immediately
  after the header and before the first block.  When doing a raw inflate,
  inflate() will go ahead and process the first block, and will return when it
  gets to the end of that block, or when it runs out of data.
M
Mark Adler 已提交
429 430 431

    The Z_BLOCK option assists in appending to or combining deflate streams.
  Also to assist in this, on return inflate() will set strm->data_type to the
M
Mark Adler 已提交
432 433 434 435 436 437 438 439 440 441 442
  number of unused bits in the last byte taken from strm->next_in, plus 64 if
  inflate() is currently decoding the last block in the deflate stream, plus
  128 if inflate() returned immediately after decoding an end-of-block code or
  decoding the complete header up to just before the first byte of the deflate
  stream.  The end-of-block will not be indicated until all of the uncompressed
  data from that block has been written to strm->next_out.  The number of
  unused bits may in general be greater than seven, except when bit 7 of
  data_type is set, in which case the number of unused bits will be less than
  eight.  data_type is set as noted here every time inflate() returns for all
  flush options, and so can be used to determine the amount of currently
  consumed input in bits.
M
Mark Adler 已提交
443 444 445 446 447 448 449

    The Z_TREES option behaves as Z_BLOCK does, but it also returns when the
  end of each deflate block header is reached, before any actual data in that
  block is decoded.  This allows the caller to determine the length of the
  deflate block header for later use in random access within a deflate block.
  256 is added to the value of strm->data_type when inflate() returns
  immediately after reaching the end of the deflate block header.
M
Mark Adler 已提交
450 451

    inflate() should normally be called until it returns Z_STREAM_END or an
M
Mark Adler 已提交
452 453 454
  error.  However if all decompression is to be performed in a single step (a
  single call of inflate), the parameter flush should be set to Z_FINISH.  In
  this case all pending input is processed and all pending output is flushed;
455 456 457 458 459 460 461 462 463 464 465
  avail_out must be large enough to hold all of the uncompressed data for the
  operation to complete.  (The size of the uncompressed data may have been
  saved by the compressor for this purpose.) The use of Z_FINISH is not
  required to perform an inflation in one step.  However it may be used to
  inform inflate that a faster approach can be used for the single inflate()
  call.  Z_FINISH also informs inflate to not maintain a sliding window if the
  stream completes, which reduces inflate's memory footprint.  If the stream
  does not complete, either because not all of the stream is provided or not
  enough output space is provided, then a sliding window will be allocated and
  inflate() can be called again to continue the operation as if Z_NO_FLUSH had
  been used.
M
Mark Adler 已提交
466

M
Mark Adler 已提交
467 468
     In this implementation, inflate() always flushes as much output as
  possible to the output buffer, and always uses the faster approach on the
469 470 471 472
  first call.  So the effects of the flush parameter in this implementation are
  on the return value of inflate() as noted below, when inflate() returns early
  when Z_BLOCK or Z_TREES is used, and when inflate() avoids the allocation of
  memory for a sliding window when Z_FINISH is used.
M
Mark Adler 已提交
473 474

     If a preset dictionary is needed after this call (see inflateSetDictionary
475
  below), inflate sets strm->adler to the Adler-32 checksum of the dictionary
M
Mark Adler 已提交
476
  chosen by the compressor and returns Z_NEED_DICT; otherwise it sets
477
  strm->adler to the Adler-32 checksum of all output produced so far (that is,
M
Mark Adler 已提交
478
  total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described
M
Mark Adler 已提交
479
  below.  At the end of the stream, inflate() checks that its computed adler32
M
Mark Adler 已提交
480 481 482
  checksum is equal to that saved by the compressor and returns Z_STREAM_END
  only if the checksum is correct.

M
Mark Adler 已提交
483 484 485 486 487
    inflate() can decompress and check either zlib-wrapped or gzip-wrapped
  deflate data.  The header type is detected automatically, if requested when
  initializing with inflateInit2().  Any information contained in the gzip
  header is not retained, so applications that need that information should
  instead use raw inflate, see inflateInit2() below, or inflateBack() and
488 489
  perform their own processing of the gzip header and trailer.  When processing
  gzip-wrapped deflate data, strm->adler32 is set to the CRC-32 of the output
M
Mark Adler 已提交
490
  produced so far.  The CRC-32 is checked against the gzip trailer.
M
Mark Adler 已提交
491 492 493 494 495

    inflate() returns Z_OK if some progress has been made (more input processed
  or more output produced), Z_STREAM_END if the end of the compressed data has
  been reached and all uncompressed output has been produced, Z_NEED_DICT if a
  preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
M
Mark Adler 已提交
496 497
  corrupted (input stream not conforming to the zlib format or incorrect check
  value), Z_STREAM_ERROR if the stream structure was inconsistent (for example
M
Mark Adler 已提交
498
  next_in or next_out was Z_NULL), Z_MEM_ERROR if there was not enough memory,
M
Mark Adler 已提交
499
  Z_BUF_ERROR if no progress is possible or if there was not enough room in the
M
Mark Adler 已提交
500
  output buffer when Z_FINISH is used.  Note that Z_BUF_ERROR is not fatal, and
M
Mark Adler 已提交
501
  inflate() can be called again with more input and more output space to
M
Mark Adler 已提交
502 503 504
  continue decompressing.  If Z_DATA_ERROR is returned, the application may
  then call inflateSync() to look for a good compression block if a partial
  recovery of the data is desired.
M
Mark Adler 已提交
505 506 507
*/


M
Mark Adler 已提交
508
ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm));
M
Mark Adler 已提交
509 510
/*
     All dynamically allocated data structures for this stream are freed.
M
Mark Adler 已提交
511 512
   This function discards any unprocessed input and does not flush any pending
   output.
M
Mark Adler 已提交
513 514

     inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state
M
Mark Adler 已提交
515
   was inconsistent.  In the error case, msg may be set but then points to a
M
Mark Adler 已提交
516 517 518
   static string (which must not be deallocated).
*/

M
Mark Adler 已提交
519

M
Mark Adler 已提交
520
                        /* Advanced functions */
M
Mark Adler 已提交
521 522 523 524 525

/*
    The following functions are needed only in some special applications.
*/

M
Mark Adler 已提交
526
/*
M
Mark Adler 已提交
527 528 529 530 531 532
ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm,
                                     int  level,
                                     int  method,
                                     int  windowBits,
                                     int  memLevel,
                                     int  strategy));
M
Mark Adler 已提交
533

M
Mark Adler 已提交
534 535 536
     This is another version of deflateInit with more compression options.  The
   fields next_in, zalloc, zfree and opaque must be initialized before by the
   caller.
M
Mark Adler 已提交
537

M
Mark Adler 已提交
538
     The method parameter is the compression method.  It must be Z_DEFLATED in
M
Mark Adler 已提交
539
   this version of the library.
M
Mark Adler 已提交
540 541

     The windowBits parameter is the base two logarithm of the window size
M
Mark Adler 已提交
542 543 544
   (the size of the history buffer).  It should be in the range 8..15 for this
   version of the library.  Larger values of this parameter result in better
   compression at the expense of memory usage.  The default value is 15 if
M
Mark Adler 已提交
545
   deflateInit is used instead.
M
Mark Adler 已提交
546

547 548 549 550 551 552 553 554
     For the current implementation of deflate(), a windowBits value of 8 (a
   window size of 256 bytes) is not supported.  As a result, a request for 8
   will result in 9 (a 512-byte window).  In that case, providing 8 to
   inflateInit2() will result in an error when the zlib header with 9 is
   checked against the initialization of inflate().  The remedy is to not use 8
   with deflateInit2() with this initialization, or at least in that case use 9
   with inflateInit2().

M
Mark Adler 已提交
555 556
     windowBits can also be -8..-15 for raw deflate.  In this case, -windowBits
   determines the window size.  deflate() will then generate raw deflate data
M
Mark Adler 已提交
557 558
   with no zlib header or trailer, and will not compute an adler32 check value.

M
Mark Adler 已提交
559
     windowBits can also be greater than 15 for optional gzip encoding.  Add
M
Mark Adler 已提交
560
   16 to windowBits to write a simple gzip header and trailer around the
M
Mark Adler 已提交
561 562 563
   compressed data instead of a zlib wrapper.  The gzip header will have no
   file name, no extra data, no comment, no modification time (set to zero), no
   header crc, and the operating system will be set to 255 (unknown).  If a
M
Mark Adler 已提交
564
   gzip stream is being written, strm->adler is a crc32 instead of an adler32.
M
Mark Adler 已提交
565

566 567 568 569
     For raw deflate or gzip encoding, a request for a 256-byte window is
   rejected as invalid, since only the zlib header provides a means of
   transmitting the window size to the decompressor.

M
Mark Adler 已提交
570
     The memLevel parameter specifies how much memory should be allocated
M
Mark Adler 已提交
571 572 573 574
   for the internal compression state.  memLevel=1 uses minimum memory but is
   slow and reduces compression ratio; memLevel=9 uses maximum memory for
   optimal speed.  The default value is 8.  See zconf.h for total memory usage
   as a function of windowBits and memLevel.
M
Mark Adler 已提交
575

M
Mark Adler 已提交
576
     The strategy parameter is used to tune the compression algorithm.  Use the
M
Mark Adler 已提交
577
   value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
M
Mark Adler 已提交
578 579
   filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no
   string match), or Z_RLE to limit match distances to one (run-length
M
Mark Adler 已提交
580 581 582
   encoding).  Filtered data consists mostly of small values with a somewhat
   random distribution.  In this case, the compression algorithm is tuned to
   compress them better.  The effect of Z_FILTERED is to force more Huffman
M
Mark Adler 已提交
583
   coding and less string matching; it is somewhat intermediate between
M
Mark Adler 已提交
584 585
   Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY.  Z_RLE is designed to be almost as
   fast as Z_HUFFMAN_ONLY, but give better compression for PNG image data.  The
M
Mark Adler 已提交
586 587 588 589
   strategy parameter only affects the compression ratio but not the
   correctness of the compressed output even if it is not set appropriately.
   Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler
   decoder for special applications.
M
Mark Adler 已提交
590

M
Mark Adler 已提交
591
     deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
M
Mark Adler 已提交
592 593 594 595 596
   memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid
   method), or Z_VERSION_ERROR if the zlib library version (zlib_version) is
   incompatible with the version assumed by the caller (ZLIB_VERSION).  msg is
   set to null if there is no error message.  deflateInit2 does not perform any
   compression: this will be done by deflate().
M
Mark Adler 已提交
597
*/
M
Mark Adler 已提交
598

M
Mark Adler 已提交
599 600 601
ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm,
                                             const Bytef *dictionary,
                                             uInt  dictLength));
M
Mark Adler 已提交
602
/*
M
Mark Adler 已提交
603
     Initializes the compression dictionary from the given byte sequence
604 605 606 607 608 609 610 611 612
   without producing any compressed output.  When using the zlib format, this
   function must be called immediately after deflateInit, deflateInit2 or
   deflateReset, and before any call of deflate.  When doing raw deflate, this
   function must be called either before any call of deflate, or immediately
   after the completion of a deflate block, i.e. after all input has been
   consumed and all output has been delivered when using any of the flush
   options Z_BLOCK, Z_PARTIAL_FLUSH, Z_SYNC_FLUSH, or Z_FULL_FLUSH.  The
   compressor and decompressor must use exactly the same dictionary (see
   inflateSetDictionary).
M
Mark Adler 已提交
613

M
Mark Adler 已提交
614 615
     The dictionary should consist of strings (byte sequences) that are likely
   to be encountered later in the data to be compressed, with the most commonly
M
Mark Adler 已提交
616
   used strings preferably put towards the end of the dictionary.  Using a
M
Mark Adler 已提交
617 618 619 620 621 622
   dictionary is most useful when the data to be compressed is short and can be
   predicted with good accuracy; the data can then be compressed better than
   with the default empty dictionary.

     Depending on the size of the compression data structures selected by
   deflateInit or deflateInit2, a part of the dictionary may in effect be
M
Mark Adler 已提交
623
   discarded, for example if the dictionary is larger than the window size
M
Mark Adler 已提交
624 625
   provided in deflateInit or deflateInit2.  Thus the strings most likely to be
   useful should be put at the end of the dictionary, not at the front.  In
M
Mark Adler 已提交
626 627
   addition, the current implementation of deflate will use at most the window
   size minus 262 bytes of the provided dictionary.
M
Mark Adler 已提交
628

M
Mark Adler 已提交
629
     Upon return of this function, strm->adler is set to the adler32 value
M
Mark Adler 已提交
630
   of the dictionary; the decompressor may later use this value to determine
M
Mark Adler 已提交
631
   which dictionary has been used by the compressor.  (The adler32 value
M
Mark Adler 已提交
632
   applies to the whole dictionary even if only a subset of the dictionary is
M
Mark Adler 已提交
633 634
   actually used by the compressor.) If a raw deflate was requested, then the
   adler32 value is not computed and strm->adler is not set.
M
Mark Adler 已提交
635 636

     deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
M
Mark Adler 已提交
637
   parameter is invalid (e.g.  dictionary being Z_NULL) or the stream state is
M
Mark Adler 已提交
638
   inconsistent (for example if deflate has already been called for this stream
639 640
   or if not at a block boundary for raw deflate).  deflateSetDictionary does
   not perform any compression: this will be done by deflate().
M
Mark Adler 已提交
641 642
*/

M
Mark Adler 已提交
643 644
ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest,
                                    z_streamp source));
M
Mark Adler 已提交
645
/*
M
Mark Adler 已提交
646
     Sets the destination stream as a complete copy of the source stream.
M
Mark Adler 已提交
647

M
Mark Adler 已提交
648
     This function can be useful when several compression strategies will be
M
Mark Adler 已提交
649
   tried, for example when there are several ways of pre-processing the input
M
Mark Adler 已提交
650
   data with a filter.  The streams that will be discarded should then be freed
M
Mark Adler 已提交
651
   by calling deflateEnd.  Note that deflateCopy duplicates the internal
M
Mark Adler 已提交
652 653
   compression state which can be quite large, so this strategy is slow and can
   consume lots of memory.
M
Mark Adler 已提交
654

M
Mark Adler 已提交
655
     deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
M
Mark Adler 已提交
656
   enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
M
Mark Adler 已提交
657
   (such as zalloc being Z_NULL).  msg is left unchanged in both source and
M
Mark Adler 已提交
658 659 660
   destination.
*/

M
Mark Adler 已提交
661
ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm));
M
Mark Adler 已提交
662
/*
663 664 665 666
     This function is equivalent to deflateEnd followed by deflateInit, but
   does not free and reallocate the internal compression state.  The stream
   will leave the compression level and any other attributes that may have been
   set unchanged.
M
Mark Adler 已提交
667

M
Mark Adler 已提交
668
     deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
M
Mark Adler 已提交
669
   stream state was inconsistent (such as zalloc or state being Z_NULL).
M
Mark Adler 已提交
670 671
*/

M
Mark Adler 已提交
672
ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm,
M
Mark Adler 已提交
673 674
                                      int level,
                                      int strategy));
M
Mark Adler 已提交
675
/*
M
Mark Adler 已提交
676
     Dynamically update the compression level and compression strategy.  The
677
   interpretation of level and strategy is as in deflateInit2().  This can be
M
Mark Adler 已提交
678
   used to switch between compression and straight copy of the input data, or
M
Mark Adler 已提交
679
   to switch to a different kind of input data requiring a different strategy.
680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704
   If the compression approach (which is a function of the level) or the
   strategy is changed, then the input available so far is compressed with the
   old level and strategy using deflate(strm, Z_BLOCK).  There are three
   approaches for the compression levels 0, 1..3, and 4..9 respectively.  The
   new level and strategy will take effect at the next call of deflate().

     If a deflate(strm, Z_BLOCK) is performed by deflateParams(), and it does
   not have enough output space to complete, then the parameter change will
   take effect at an undetermined location in the uncompressed data provided so
   far.  In order to assure a change in the parameters at a specific location
   in the uncompressed data, the deflate stream should first be flushed with
   Z_BLOCK or another flush parameter, and deflate() called until
   strm.avail_out is not zero, before the call of deflateParams().  Then no
   more input data should be provided before the deflateParams() call.  If this
   is done, the old level and strategy will be applied to the data compressed
   before deflateParams(), and the new level and strategy will be applied to
   the the data compressed after deflateParams().

     deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source stream
   state was inconsistent or if a parameter was invalid, or Z_BUF_ERROR if
   there was not enough output space to complete the compression before the
   parameters were changed.  Note that in the case of a Z_BUF_ERROR, the
   parameters are changed nevertheless, and will take effect at an undetermined
   location in the previously supplied uncompressed data.  Compression may
   proceed after a Z_BUF_ERROR.
M
Mark Adler 已提交
705 706
*/

M
Mark Adler 已提交
707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723
ZEXTERN int ZEXPORT deflateTune OF((z_streamp strm,
                                    int good_length,
                                    int max_lazy,
                                    int nice_length,
                                    int max_chain));
/*
     Fine tune deflate's internal compression parameters.  This should only be
   used by someone who understands the algorithm used by zlib's deflate for
   searching for the best matching string, and even then only by the most
   fanatic optimizer trying to squeeze out the last compressed bit for their
   specific input data.  Read the deflate.c source code for the meaning of the
   max_lazy, good_length, nice_length, and max_chain parameters.

     deflateTune() can be called after deflateInit() or deflateInit2(), and
   returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream.
 */

M
Mark Adler 已提交
724 725 726 727
ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm,
                                       uLong sourceLen));
/*
     deflateBound() returns an upper bound on the compressed size after
M
Mark Adler 已提交
728 729 730
   deflation of sourceLen bytes.  It must be called after deflateInit() or
   deflateInit2(), and after deflateSetHeader(), if used.  This would be used
   to allocate an output buffer for deflation in a single pass, and so would be
M
Mark Adler 已提交
731 732 733 734 735 736 737
   called before deflate().  If that first deflate() call is provided the
   sourceLen input bytes, an output buffer allocated to the size returned by
   deflateBound(), and the flush value Z_FINISH, then deflate() is guaranteed
   to return Z_STREAM_END.  Note that it is possible for the compressed size to
   be larger than the value returned by deflateBound() if flush options other
   than Z_FINISH or Z_NO_FLUSH are used.
*/
738

M
Mark Adler 已提交
739 740 741 742 743 744 745 746
ZEXTERN int ZEXPORT deflatePending OF((z_streamp strm,
                                       unsigned *pending,
                                       int *bits));
/*
     deflatePending() returns the number of bytes and bits of output that have
   been generated, but not yet provided in the available output.  The bytes not
   provided would be due to the available output space having being consumed.
   The number of bits of output not provided are between 0 and 7, where they
747 748
   await more bits to join them in order to fill out a full byte.  If pending
   or bits are Z_NULL, then those values are not set.
749

M
Mark Adler 已提交
750 751 752
     deflatePending returns Z_OK if success, or Z_STREAM_ERROR if the source
   stream state was inconsistent.
 */
M
Mark Adler 已提交
753

M
Mark Adler 已提交
754 755 756 757 758
ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm,
                                     int bits,
                                     int value));
/*
     deflatePrime() inserts bits in the deflate output stream.  The intent
M
Mark Adler 已提交
759 760 761 762 763 764 765
   is that this function is used to start off the deflate output with the bits
   leftover from a previous deflate stream when appending to it.  As such, this
   function can only be used for raw deflate, and must be used before the first
   deflate() call after a deflateInit2() or deflateReset().  bits must be less
   than or equal to 16, and that many of the least significant bits of value
   will be inserted in the output.

766 767 768
     deflatePrime returns Z_OK if success, Z_BUF_ERROR if there was not enough
   room in the internal buffer to insert the bits, or Z_STREAM_ERROR if the
   source stream state was inconsistent.
M
Mark Adler 已提交
769 770
*/

M
Mark Adler 已提交
771 772 773
ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm,
                                         gz_headerp head));
/*
M
Mark Adler 已提交
774
     deflateSetHeader() provides gzip header information for when a gzip
M
Mark Adler 已提交
775 776 777 778 779 780 781 782 783 784 785 786
   stream is requested by deflateInit2().  deflateSetHeader() may be called
   after deflateInit2() or deflateReset() and before the first call of
   deflate().  The text, time, os, extra field, name, and comment information
   in the provided gz_header structure are written to the gzip header (xflag is
   ignored -- the extra flags are set according to the compression level).  The
   caller must assure that, if not Z_NULL, name and comment are terminated with
   a zero byte, and that if extra is not Z_NULL, that extra_len bytes are
   available there.  If hcrc is true, a gzip header crc is included.  Note that
   the current versions of the command-line version of gzip (up through version
   1.3.x) do not support header crc's, and will report that it is a "multi-part
   gzip file" and give up.

M
Mark Adler 已提交
787
     If deflateSetHeader is not used, the default gzip header has text false,
M
Mark Adler 已提交
788 789 790
   the time set to zero, and os set to 255, with no extra, name, or comment
   fields.  The gzip header is returned to the default state by deflateReset().

M
Mark Adler 已提交
791
     deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
M
Mark Adler 已提交
792 793 794
   stream state was inconsistent.
*/

M
Mark Adler 已提交
795
/*
M
Mark Adler 已提交
796 797
ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm,
                                     int  windowBits));
M
Mark Adler 已提交
798

M
Mark Adler 已提交
799
     This is another version of inflateInit with an extra parameter.  The
M
Mark Adler 已提交
800 801
   fields next_in, avail_in, zalloc, zfree and opaque must be initialized
   before by the caller.
M
Mark Adler 已提交
802 803 804

     The windowBits parameter is the base two logarithm of the maximum window
   size (the size of the history buffer).  It should be in the range 8..15 for
M
Mark Adler 已提交
805 806
   this version of the library.  The default value is 15 if inflateInit is used
   instead.  windowBits must be greater than or equal to the windowBits value
M
Mark Adler 已提交
807
   provided to deflateInit2() while compressing, or it must be equal to 15 if
M
Mark Adler 已提交
808
   deflateInit2() was not used.  If a compressed stream with a larger window
M
Mark Adler 已提交
809 810 811
   size is given as input, inflate() will return with the error code
   Z_DATA_ERROR instead of trying to allocate a larger window.

M
Mark Adler 已提交
812 813 814
     windowBits can also be zero to request that inflate use the window size in
   the zlib header of the compressed stream.

M
Mark Adler 已提交
815 816
     windowBits can also be -8..-15 for raw inflate.  In this case, -windowBits
   determines the window size.  inflate() will then process raw deflate data,
M
Mark Adler 已提交
817
   not looking for a zlib or gzip header, not generating a check value, and not
M
Mark Adler 已提交
818
   looking for any check values for comparison at the end of the stream.  This
M
Mark Adler 已提交
819
   is for use with other formats that use the deflate compressed data format
M
Mark Adler 已提交
820
   such as zip.  Those formats provide their own check values.  If a custom
M
Mark Adler 已提交
821 822 823
   format is developed using the raw deflate format for compressed data, it is
   recommended that a check value such as an adler32 or a crc32 be applied to
   the uncompressed data as is done in the zlib, gzip, and zip formats.  For
M
Mark Adler 已提交
824
   most applications, the zlib format should be used as is.  Note that comments
M
Mark Adler 已提交
825 826
   above on the use in deflateInit2() applies to the magnitude of windowBits.

M
Mark Adler 已提交
827
     windowBits can also be greater than 15 for optional gzip decoding.  Add
M
Mark Adler 已提交
828 829
   32 to windowBits to enable zlib and gzip decoding with automatic header
   detection, or add 16 to decode only the gzip format (the zlib format will
M
Mark Adler 已提交
830 831
   return a Z_DATA_ERROR).  If a gzip stream is being decoded, strm->adler is a
   crc32 instead of an adler32.
M
Mark Adler 已提交
832 833

     inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
M
Mark Adler 已提交
834 835 836
   memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
   version assumed by the caller, or Z_STREAM_ERROR if the parameters are
   invalid, such as a null pointer to the structure.  msg is set to null if
M
Mark Adler 已提交
837
   there is no error message.  inflateInit2 does not perform any decompression
M
Mark Adler 已提交
838 839
   apart from possibly reading the zlib header if present: actual decompression
   will be done by inflate().  (So next_in and avail_in may be modified, but
M
Mark Adler 已提交
840 841 842
   next_out and avail_out are unused and unchanged.) The current implementation
   of inflateInit2() does not process any header information -- that is
   deferred until inflate() is called.
M
Mark Adler 已提交
843 844
*/

M
Mark Adler 已提交
845 846 847
ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm,
                                             const Bytef *dictionary,
                                             uInt  dictLength));
M
Mark Adler 已提交
848
/*
M
Mark Adler 已提交
849
     Initializes the decompression dictionary from the given uncompressed byte
M
Mark Adler 已提交
850 851
   sequence.  This function must be called immediately after a call of inflate,
   if that call returned Z_NEED_DICT.  The dictionary chosen by the compressor
M
Mark Adler 已提交
852 853
   can be determined from the adler32 value returned by that call of inflate.
   The compressor and decompressor must use exactly the same dictionary (see
854 855 856 857 858
   deflateSetDictionary).  For raw inflate, this function can be called at any
   time to set the dictionary.  If the provided dictionary is smaller than the
   window and there is already data in the window, then the provided dictionary
   will amend what's there.  The application must insure that the dictionary
   that was used for compression is provided.
M
Mark Adler 已提交
859 860

     inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
M
Mark Adler 已提交
861
   parameter is invalid (e.g.  dictionary being Z_NULL) or the stream state is
M
Mark Adler 已提交
862
   inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
M
Mark Adler 已提交
863
   expected one (incorrect adler32 value).  inflateSetDictionary does not
M
Mark Adler 已提交
864 865 866 867
   perform any decompression: this will be done by subsequent calls of
   inflate().
*/

868 869 870 871 872 873 874 875 876 877 878
ZEXTERN int ZEXPORT inflateGetDictionary OF((z_streamp strm,
                                             Bytef *dictionary,
                                             uInt  *dictLength));
/*
     Returns the sliding dictionary being maintained by inflate.  dictLength is
   set to the number of bytes in the dictionary, and that many bytes are copied
   to dictionary.  dictionary must have enough space, where 32768 bytes is
   always enough.  If inflateGetDictionary() is called with dictionary equal to
   Z_NULL, then only the dictionary length is returned, and nothing is copied.
   Similary, if dictLength is Z_NULL, then it is not set.

879
     inflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the
880 881 882
   stream state is inconsistent.
*/

M
Mark Adler 已提交
883
ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm));
M
Mark Adler 已提交
884
/*
M
Mark Adler 已提交
885 886
     Skips invalid compressed data until a possible full flush point (see above
   for the description of deflate with Z_FULL_FLUSH) can be found, or until all
M
Mark Adler 已提交
887 888
   available input is skipped.  No output is provided.

M
Mark Adler 已提交
889
     inflateSync searches for a 00 00 FF FF pattern in the compressed data.
M
Mark Adler 已提交
890
   All full flush points have this pattern, but not all occurrences of this
M
Mark Adler 已提交
891 892 893 894 895 896 897 898 899
   pattern are full flush points.

     inflateSync returns Z_OK if a possible full flush point has been found,
   Z_BUF_ERROR if no more input was provided, Z_DATA_ERROR if no flush point
   has been found, or Z_STREAM_ERROR if the stream structure was inconsistent.
   In the success case, the application may save the current current value of
   total_in which indicates where valid compressed data was found.  In the
   error case, the application may repeatedly call inflateSync, providing more
   input each time, until success or end of the input data.
M
Mark Adler 已提交
900 901
*/

M
Mark Adler 已提交
902 903 904 905 906 907 908 909 910 911 912 913
ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest,
                                    z_streamp source));
/*
     Sets the destination stream as a complete copy of the source stream.

     This function can be useful when randomly accessing a large stream.  The
   first pass through the stream can periodically record the inflate state,
   allowing restarting inflate at those points when randomly accessing the
   stream.

     inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
   enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
M
Mark Adler 已提交
914
   (such as zalloc being Z_NULL).  msg is left unchanged in both source and
M
Mark Adler 已提交
915 916 917
   destination.
*/

M
Mark Adler 已提交
918
ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm));
M
Mark Adler 已提交
919 920
/*
     This function is equivalent to inflateEnd followed by inflateInit,
M
Mark Adler 已提交
921 922
   but does not free and reallocate all the internal decompression state.  The
   stream will keep attributes that may have been set by inflateInit2.
M
Mark Adler 已提交
923

M
Mark Adler 已提交
924
     inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
M
Mark Adler 已提交
925 926 927 928 929 930 931
   stream state was inconsistent (such as zalloc or state being Z_NULL).
*/

ZEXTERN int ZEXPORT inflateReset2 OF((z_streamp strm,
                                      int windowBits));
/*
     This function is the same as inflateReset, but it also permits changing
M
Mark Adler 已提交
932 933
   the wrap and window size requests.  The windowBits parameter is interpreted
   the same as it is for inflateInit2.
M
Mark Adler 已提交
934

M
Mark Adler 已提交
935
     inflateReset2 returns Z_OK if success, or Z_STREAM_ERROR if the source
M
Mark Adler 已提交
936 937
   stream state was inconsistent (such as zalloc or state being Z_NULL), or if
   the windowBits parameter is invalid.
M
Mark Adler 已提交
938 939
*/

M
Mark Adler 已提交
940 941 942 943 944
ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm,
                                     int bits,
                                     int value));
/*
     This function inserts bits in the inflate input stream.  The intent is
M
Mark Adler 已提交
945 946 947 948 949 950
   that this function is used to start inflating at a bit position in the
   middle of a byte.  The provided bits will be used before any bytes are used
   from next_in.  This function should only be used with raw inflate, and
   should be used before the first inflate() call after inflateInit2() or
   inflateReset().  bits must be less than or equal to 16, and that many of the
   least significant bits of value will be inserted in the input.
M
Mark Adler 已提交
951

M
Mark Adler 已提交
952
     If bits is negative, then the input stream bit buffer is emptied.  Then
M
Mark Adler 已提交
953 954 955
   inflatePrime() can be called again to put bits in the buffer.  This is used
   to clear out bits leftover after feeding inflate a block description prior
   to feeding inflate codes.
M
Mark Adler 已提交
956

M
Mark Adler 已提交
957
     inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source
M
Mark Adler 已提交
958 959 960
   stream state was inconsistent.
*/

M
Mark Adler 已提交
961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978
ZEXTERN long ZEXPORT inflateMark OF((z_streamp strm));
/*
     This function returns two values, one in the lower 16 bits of the return
   value, and the other in the remaining upper bits, obtained by shifting the
   return value down 16 bits.  If the upper value is -1 and the lower value is
   zero, then inflate() is currently decoding information outside of a block.
   If the upper value is -1 and the lower value is non-zero, then inflate is in
   the middle of a stored block, with the lower value equaling the number of
   bytes from the input remaining to copy.  If the upper value is not -1, then
   it is the number of bits back from the current bit position in the input of
   the code (literal or length/distance pair) currently being processed.  In
   that case the lower value is the number of bytes already emitted for that
   code.

     A code is being processed if inflate is waiting for more input to complete
   decoding of the code, or if it has completed decoding but is waiting for
   more output space to write the literal or match data.

M
Mark Adler 已提交
979
     inflateMark() is used to mark locations in the input data for random
M
Mark Adler 已提交
980 981 982 983 984
   access, which may be at bit positions, and to note those cases where the
   output of a code may span boundaries of random access blocks.  The current
   location in the input stream can be determined from avail_in and data_type
   as noted in the description for the Z_BLOCK flush parameter for inflate.

985
     inflateMark returns the value noted above or -65536 if the provided
M
Mark Adler 已提交
986 987 988
   source stream state was inconsistent.
*/

M
Mark Adler 已提交
989 990 991
ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm,
                                         gz_headerp head));
/*
M
Mark Adler 已提交
992
     inflateGetHeader() requests that gzip header information be stored in the
M
Mark Adler 已提交
993 994 995 996 997
   provided gz_header structure.  inflateGetHeader() may be called after
   inflateInit2() or inflateReset(), and before the first call of inflate().
   As inflate() processes the gzip stream, head->done is zero until the header
   is completed, at which time head->done is set to one.  If a zlib stream is
   being decoded, then head->done is set to -1 to indicate that there will be
M
Mark Adler 已提交
998 999 1000
   no gzip header information forthcoming.  Note that Z_BLOCK or Z_TREES can be
   used to force inflate() to return immediately after header processing is
   complete and before any actual data is decompressed.
M
Mark Adler 已提交
1001

M
Mark Adler 已提交
1002
     The text, time, xflags, and os fields are filled in with the gzip header
M
Mark Adler 已提交
1003
   contents.  hcrc is set to true if there is a header CRC.  (The header CRC
M
Mark Adler 已提交
1004
   was valid if done is set to one.) If extra is not Z_NULL, then extra_max
M
Mark Adler 已提交
1005 1006 1007 1008 1009 1010
   contains the maximum number of bytes to write to extra.  Once done is true,
   extra_len contains the actual extra field length, and extra contains the
   extra field, or that field truncated if extra_max is less than extra_len.
   If name is not Z_NULL, then up to name_max characters are written there,
   terminated with a zero unless the length is greater than name_max.  If
   comment is not Z_NULL, then up to comm_max characters are written there,
M
Mark Adler 已提交
1011 1012 1013
   terminated with a zero unless the length is greater than comm_max.  When any
   of extra, name, or comment are not Z_NULL and the respective field is not
   present in the header, then that field is set to Z_NULL to signal its
M
Mark Adler 已提交
1014 1015 1016 1017 1018
   absence.  This allows the use of deflateSetHeader() with the returned
   structure to duplicate the header.  However if those fields are set to
   allocated memory, then the application will need to save those pointers
   elsewhere so that they can be eventually freed.

M
Mark Adler 已提交
1019
     If inflateGetHeader is not used, then the header information is simply
M
Mark Adler 已提交
1020 1021 1022 1023 1024
   discarded.  The header is always checked for validity, including the header
   CRC if present.  inflateReset() will reset the process to discard the header
   information.  The application would need to call inflateGetHeader() again to
   retrieve the header from the next gzip stream.

M
Mark Adler 已提交
1025
     inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
M
Mark Adler 已提交
1026 1027 1028
   stream state was inconsistent.
*/

M
Mark Adler 已提交
1029
/*
M
Mark Adler 已提交
1030
ZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits,
M
Mark Adler 已提交
1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045
                                        unsigned char FAR *window));

     Initialize the internal stream state for decompression using inflateBack()
   calls.  The fields zalloc, zfree and opaque in strm must be initialized
   before the call.  If zalloc and zfree are Z_NULL, then the default library-
   derived memory allocation routines are used.  windowBits is the base two
   logarithm of the window size, in the range 8..15.  window is a caller
   supplied buffer of that size.  Except for special applications where it is
   assured that deflate was used with small window sizes, windowBits must be 15
   and a 32K byte window must be supplied to be able to decompress general
   deflate streams.

     See inflateBack() for the usage of these routines.

     inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of
M
Mark Adler 已提交
1046
   the parameters are invalid, Z_MEM_ERROR if the internal state could not be
M
Mark Adler 已提交
1047 1048
   allocated, or Z_VERSION_ERROR if the version of the library does not match
   the version of the header file.
M
Mark Adler 已提交
1049 1050
*/

1051 1052
typedef unsigned (*in_func) OF((void FAR *,
                                z_const unsigned char FAR * FAR *));
M
Mark Adler 已提交
1053 1054
typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned));

M
Mark Adler 已提交
1055
ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm,
M
Mark Adler 已提交
1056 1057 1058 1059
                                    in_func in, void FAR *in_desc,
                                    out_func out, void FAR *out_desc));
/*
     inflateBack() does a raw inflate with a single call using a call-back
1060 1061 1062 1063 1064 1065
   interface for input and output.  This is potentially more efficient than
   inflate() for file i/o applications, in that it avoids copying between the
   output and the sliding window by simply making the window itself the output
   buffer.  inflate() can be faster on modern CPUs when used with large
   buffers.  inflateBack() trusts the application to not change the output
   buffer passed by the output function, at least until inflateBack() returns.
M
Mark Adler 已提交
1066 1067 1068 1069

     inflateBackInit() must be called first to allocate the internal state
   and to initialize the state with the user-provided window buffer.
   inflateBack() may then be used multiple times to inflate a complete, raw
M
Mark Adler 已提交
1070 1071
   deflate stream with each call.  inflateBackEnd() is then called to free the
   allocated state.
M
Mark Adler 已提交
1072 1073 1074 1075

     A raw deflate stream is one with no zlib or gzip header or trailer.
   This routine would normally be used in a utility that reads zip or gzip
   files and writes out uncompressed files.  The utility would decode the
M
Mark Adler 已提交
1076 1077 1078
   header and process the trailer on its own, hence this routine expects only
   the raw deflate stream to decompress.  This is different from the normal
   behavior of inflate(), which expects either a zlib or gzip header and
M
Mark Adler 已提交
1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103
   trailer around the deflate stream.

     inflateBack() uses two subroutines supplied by the caller that are then
   called by inflateBack() for input and output.  inflateBack() calls those
   routines until it reads a complete deflate stream and writes out all of the
   uncompressed data, or until it encounters an error.  The function's
   parameters and return types are defined above in the in_func and out_func
   typedefs.  inflateBack() will call in(in_desc, &buf) which should return the
   number of bytes of provided input, and a pointer to that input in buf.  If
   there is no input available, in() must return zero--buf is ignored in that
   case--and inflateBack() will return a buffer error.  inflateBack() will call
   out(out_desc, buf, len) to write the uncompressed data buf[0..len-1].  out()
   should return zero on success, or non-zero on failure.  If out() returns
   non-zero, inflateBack() will return with an error.  Neither in() nor out()
   are permitted to change the contents of the window provided to
   inflateBackInit(), which is also the buffer that out() uses to write from.
   The length written by out() will be at most the window size.  Any non-zero
   amount of input may be provided by in().

     For convenience, inflateBack() can be provided input on the first call by
   setting strm->next_in and strm->avail_in.  If that input is exhausted, then
   in() will be called.  Therefore strm->next_in must be initialized before
   calling inflateBack().  If strm->next_in is Z_NULL, then in() will be called
   immediately for input.  If strm->next_in is not Z_NULL, then strm->avail_in
   must also be initialized, and then if strm->avail_in is not zero, input will
M
Mark Adler 已提交
1104
   initially be taken from strm->next_in[0 ..  strm->avail_in - 1].
M
Mark Adler 已提交
1105 1106 1107

     The in_desc and out_desc parameters of inflateBack() is passed as the
   first parameter of in() and out() respectively when they are called.  These
M
Mark Adler 已提交
1108
   descriptors can be optionally used to pass any information that the caller-
M
Mark Adler 已提交
1109 1110 1111 1112 1113
   supplied in() and out() functions need to do their job.

     On return, inflateBack() will set strm->next_in and strm->avail_in to
   pass back any unused input that was provided by the last in() call.  The
   return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR
M
Mark Adler 已提交
1114 1115 1116 1117 1118 1119 1120 1121 1122
   if in() or out() returned an error, Z_DATA_ERROR if there was a format error
   in the deflate stream (in which case strm->msg is set to indicate the nature
   of the error), or Z_STREAM_ERROR if the stream was not properly initialized.
   In the case of Z_BUF_ERROR, an input or output error can be distinguished
   using strm->next_in which will be Z_NULL only if in() returned an error.  If
   strm->next_in is not Z_NULL, then the Z_BUF_ERROR was due to out() returning
   non-zero.  (in() will always be called before out(), so strm->next_in is
   assured to be defined if out() returns non-zero.) Note that inflateBack()
   cannot return Z_OK.
M
Mark Adler 已提交
1123 1124
*/

M
Mark Adler 已提交
1125
ZEXTERN int ZEXPORT inflateBackEnd OF((z_streamp strm));
M
Mark Adler 已提交
1126 1127 1128 1129 1130 1131 1132
/*
     All memory allocated by inflateBackInit() is freed.

     inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream
   state was inconsistent.
*/

M
Mark Adler 已提交
1133 1134 1135 1136 1137 1138
ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void));
/* Return flags indicating compile-time options.

    Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other:
     1.0: size of uInt
     3.2: size of uLong
M
Mark Adler 已提交
1139
     5.4: size of voidpf (pointer)
M
Mark Adler 已提交
1140 1141
     7.6: size of z_off_t

M
Mark Adler 已提交
1142
    Compiler, assembler, and debug options:
1143
     8: ZLIB_DEBUG
M
Mark Adler 已提交
1144 1145 1146
     9: ASMV or ASMINF -- use ASM code
     10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention
     11: 0 (reserved)
M
Mark Adler 已提交
1147 1148 1149 1150 1151 1152 1153

    One-time table building (smaller code, but not thread-safe if true):
     12: BUILDFIXED -- build static block decoding tables when needed
     13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed
     14,15: 0 (reserved)

    Library content (indicates missing functionality):
M
Mark Adler 已提交
1154 1155
     16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking
                          deflate code when not needed)
M
Mark Adler 已提交
1156 1157
     17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect
                    and decode gzip streams (to avoid linking crc code)
M
Mark Adler 已提交
1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173
     18-19: 0 (reserved)

    Operation variations (changes in library functionality):
     20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate
     21: FASTEST -- deflate algorithm with only one, lowest compression level
     22,23: 0 (reserved)

    The sprintf variant used by gzprintf (zero is best):
     24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format
     25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure!
     26: 0 = returns value, 1 = void -- 1 means inferred string length returned

    Remainder:
     27-31: 0 (reserved)
 */

1174
#ifndef Z_SOLO
M
Mark Adler 已提交
1175 1176 1177 1178

                        /* utility functions */

/*
M
Mark Adler 已提交
1179 1180 1181 1182 1183
     The following utility functions are implemented on top of the basic
   stream-oriented functions.  To simplify the interface, some default options
   are assumed (compression level and memory usage, standard memory allocation
   functions).  The source code of these utility functions can be modified if
   you need special options.
M
Mark Adler 已提交
1184 1185
*/

M
Mark Adler 已提交
1186 1187
ZEXTERN int ZEXPORT compress OF((Bytef *dest,   uLongf *destLen,
                                 const Bytef *source, uLong sourceLen));
M
Mark Adler 已提交
1188 1189
/*
     Compresses the source buffer into the destination buffer.  sourceLen is
M
Mark Adler 已提交
1190 1191 1192
   the byte length of the source buffer.  Upon entry, destLen is the total size
   of the destination buffer, which must be at least the value returned by
   compressBound(sourceLen).  Upon exit, destLen is the actual size of the
1193 1194
   compressed buffer.  compress() is equivalent to compress2() with a level
   parameter of Z_DEFAULT_COMPRESSION.
M
Mark Adler 已提交
1195

M
Mark Adler 已提交
1196 1197 1198 1199 1200
     compress returns Z_OK if success, Z_MEM_ERROR if there was not
   enough memory, Z_BUF_ERROR if there was not enough room in the output
   buffer.
*/

M
Mark Adler 已提交
1201 1202 1203
ZEXTERN int ZEXPORT compress2 OF((Bytef *dest,   uLongf *destLen,
                                  const Bytef *source, uLong sourceLen,
                                  int level));
M
Mark Adler 已提交
1204
/*
M
Mark Adler 已提交
1205
     Compresses the source buffer into the destination buffer.  The level
M
Mark Adler 已提交
1206
   parameter has the same meaning as in deflateInit.  sourceLen is the byte
M
Mark Adler 已提交
1207
   length of the source buffer.  Upon entry, destLen is the total size of the
M
Mark Adler 已提交
1208
   destination buffer, which must be at least the value returned by
M
Mark Adler 已提交
1209
   compressBound(sourceLen).  Upon exit, destLen is the actual size of the
M
Mark Adler 已提交
1210
   compressed buffer.
M
Mark Adler 已提交
1211 1212 1213 1214 1215 1216

     compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
   memory, Z_BUF_ERROR if there was not enough room in the output buffer,
   Z_STREAM_ERROR if the level parameter is invalid.
*/

M
Mark Adler 已提交
1217 1218 1219
ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen));
/*
     compressBound() returns an upper bound on the compressed size after
M
Mark Adler 已提交
1220 1221
   compress() or compress2() on sourceLen bytes.  It would be used before a
   compress() or compress2() call to allocate the destination buffer.
M
Mark Adler 已提交
1222 1223
*/

M
Mark Adler 已提交
1224 1225
ZEXTERN int ZEXPORT uncompress OF((Bytef *dest,   uLongf *destLen,
                                   const Bytef *source, uLong sourceLen));
M
Mark Adler 已提交
1226 1227
/*
     Decompresses the source buffer into the destination buffer.  sourceLen is
M
Mark Adler 已提交
1228 1229 1230 1231 1232 1233
   the byte length of the source buffer.  Upon entry, destLen is the total size
   of the destination buffer, which must be large enough to hold the entire
   uncompressed data.  (The size of the uncompressed data must have been saved
   previously by the compressor and transmitted to the decompressor by some
   mechanism outside the scope of this compression library.) Upon exit, destLen
   is the actual size of the uncompressed buffer.
M
Mark Adler 已提交
1234 1235 1236

     uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
   enough memory, Z_BUF_ERROR if there was not enough room in the output
1237 1238 1239
   buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete.  In
   the case where there is not enough room, uncompress() will fill the output
   buffer with the uncompressed data up to that point.
M
Mark Adler 已提交
1240 1241
*/

M
Mark Adler 已提交
1242 1243
                        /* gzip file access functions */

M
Mark Adler 已提交
1244
/*
M
Mark Adler 已提交
1245 1246 1247 1248
     This library supports reading and writing files in gzip (.gz) format with
   an interface similar to that of stdio, using the functions that start with
   "gz".  The gzip format is different from the zlib format.  gzip is a gzip
   wrapper, documented in RFC 1952, wrapped around a deflate stream.
M
Mark Adler 已提交
1249
*/
M
Mark Adler 已提交
1250

1251
typedef struct gzFile_s *gzFile;    /* semi-opaque gzip file descriptor */
M
Mark Adler 已提交
1252 1253

/*
M
Mark Adler 已提交
1254
ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode));
M
Mark Adler 已提交
1255

M
Mark Adler 已提交
1256 1257 1258 1259 1260
     Opens a gzip (.gz) file for reading or writing.  The mode parameter is as
   in fopen ("rb" or "wb") but can also include a compression level ("wb9") or
   a strategy: 'f' for filtered data as in "wb6f", 'h' for Huffman-only
   compression as in "wb1h", 'R' for run-length encoding as in "wb1R", or 'F'
   for fixed code compression as in "wb9F".  (See the description of
1261 1262 1263 1264 1265 1266
   deflateInit2 for more information about the strategy parameter.)  'T' will
   request transparent writing or appending with no compression and not using
   the gzip format.

     "a" can be used instead of "w" to request that the gzip stream that will
   be written be appended to the file.  "+" will result in an error, since
1267 1268 1269 1270
   reading and writing to the same gzip file is not supported.  The addition of
   "x" when writing will create the file exclusively, which fails if the file
   already exists.  On systems that support it, the addition of "e" when
   reading or writing will set the flag to close the file on an execve() call.
M
Mark Adler 已提交
1271

1272 1273 1274 1275 1276 1277 1278
     These functions, as well as gzip, will read and decode a sequence of gzip
   streams in a file.  The append function of gzopen() can be used to create
   such a file.  (Also see gzflush() for another way to do this.)  When
   appending, gzopen does not test whether the file begins with a gzip stream,
   nor does it look for the end of the gzip streams to begin appending.  gzopen
   will simply append a gzip stream to the existing file.

M
Mark Adler 已提交
1279
     gzopen can be used to read a file which is not in gzip format; in this
1280 1281 1282
   case gzread will directly read from the file without decompression.  When
   reading, this will be detected automatically by looking for the magic two-
   byte gzip header.
M
Mark Adler 已提交
1283

M
Mark Adler 已提交
1284 1285 1286 1287 1288
     gzopen returns NULL if the file could not be opened, if there was
   insufficient memory to allocate the gzFile state, or if an invalid mode was
   specified (an 'r', 'w', or 'a' was not provided, or '+' was provided).
   errno can be checked to determine if the reason gzopen failed was that the
   file could not be opened.
M
Mark Adler 已提交
1289
*/
M
Mark Adler 已提交
1290

M
Mark Adler 已提交
1291
ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode));
M
Mark Adler 已提交
1292
/*
M
Mark Adler 已提交
1293 1294 1295
     gzdopen associates a gzFile with the file descriptor fd.  File descriptors
   are obtained from calls like open, dup, creat, pipe or fileno (if the file
   has been previously opened with fopen).  The mode parameter is as in gzopen.
M
Mark Adler 已提交
1296 1297

     The next call of gzclose on the returned gzFile will also close the file
M
Mark Adler 已提交
1298 1299 1300
   descriptor fd, just like fclose(fdopen(fd, mode)) closes the file descriptor
   fd.  If you want to keep fd open, use fd = dup(fd_keep); gz = gzdopen(fd,
   mode);.  The duplicated descriptor should be saved to avoid a leak, since
1301 1302 1303 1304 1305
   gzdopen does not close fd if it fails.  If you are using fileno() to get the
   file descriptor from a FILE *, then you will have to use dup() to avoid
   double-close()ing the file descriptor.  Both gzclose() and fclose() will
   close the associated file descriptor, so they need to have different file
   descriptors.
M
Mark Adler 已提交
1306 1307

     gzdopen returns NULL if there was insufficient memory to allocate the
M
Mark Adler 已提交
1308 1309 1310 1311
   gzFile state, if an invalid mode was specified (an 'r', 'w', or 'a' was not
   provided, or '+' was provided), or if fd is -1.  The file descriptor is not
   used until the next gz* read, write, seek, or close operation, so gzdopen
   will not detect if fd is invalid (unless fd is -1).
M
Mark Adler 已提交
1312 1313
*/

M
Mark Adler 已提交
1314 1315
ZEXTERN int ZEXPORT gzbuffer OF((gzFile file, unsigned size));
/*
M
Mark Adler 已提交
1316 1317 1318 1319
     Set the internal buffer size used by this library's functions.  The
   default buffer size is 8192 bytes.  This function must be called after
   gzopen() or gzdopen(), and before any other calls that read or write the
   file.  The buffer memory allocation is always deferred to the first read or
1320 1321 1322
   write.  Three times that size in buffer space is allocated.  A larger buffer
   size of, for example, 64K or 128K bytes will noticeably increase the speed
   of decompression (reading).
M
Mark Adler 已提交
1323 1324 1325 1326

     The new buffer size also affects the maximum length for gzprintf().

     gzbuffer() returns 0 on success, or -1 on failure, such as being called
M
Mark Adler 已提交
1327 1328 1329
   too late.
*/

M
Mark Adler 已提交
1330
ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy));
M
Mark Adler 已提交
1331
/*
M
Mark Adler 已提交
1332
     Dynamically update the compression level or strategy.  See the description
M
Mark Adler 已提交
1333
   of deflateInit2 for the meaning of these parameters.
M
Mark Adler 已提交
1334

M
Mark Adler 已提交
1335 1336 1337 1338
     gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not
   opened for writing.
*/

M
Mark Adler 已提交
1339
ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len));
M
Mark Adler 已提交
1340
/*
M
Mark Adler 已提交
1341
     Reads the given number of uncompressed bytes from the compressed file.  If
1342 1343
   the input file is not in gzip format, gzread copies the given number of
   bytes into the buffer directly from the file.
M
Mark Adler 已提交
1344 1345

     After reaching the end of a gzip stream in the input, gzread will continue
1346 1347 1348 1349
   to read, looking for another gzip stream.  Any number of gzip streams may be
   concatenated in the input file, and will all be decompressed by gzread().
   If something other than a gzip stream is encountered after a gzip stream,
   that remaining trailing garbage is ignored (and no error is returned).
M
Mark Adler 已提交
1350

1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362
     gzread can be used to read a gzip file that is being concurrently written.
   Upon reaching the end of the input, gzread will return with the available
   data.  If the error code returned by gzerror is Z_OK or Z_BUF_ERROR, then
   gzclearerr can be used to clear the end of file indicator in order to permit
   gzread to be tried again.  Z_OK indicates that a gzip stream was completed
   on the last gzread.  Z_BUF_ERROR indicates that the input file ended in the
   middle of a gzip stream.  Note that gzread does not return -1 in the event
   of an incomplete gzip stream.  This error is deferred until gzclose(), which
   will return Z_BUF_ERROR if the last gzread ended in the middle of a gzip
   stream.  Alternatively, gzerror can be used before gzclose to detect this
   case.

M
Mark Adler 已提交
1363 1364
     gzread returns the number of uncompressed bytes actually read, less than
   len for end of file, or -1 for error.
M
Mark Adler 已提交
1365
*/
M
Mark Adler 已提交
1366

M
Mark Adler 已提交
1367 1368
ZEXTERN int ZEXPORT gzwrite OF((gzFile file,
                                voidpc buf, unsigned len));
M
Mark Adler 已提交
1369 1370
/*
     Writes the given number of uncompressed bytes into the compressed file.
M
Mark Adler 已提交
1371 1372
   gzwrite returns the number of uncompressed bytes written or 0 in case of
   error.
M
Mark Adler 已提交
1373 1374
*/

1375
ZEXTERN int ZEXPORTVA gzprintf Z_ARG((gzFile file, const char *format, ...));
M
Mark Adler 已提交
1376
/*
M
Mark Adler 已提交
1377
     Converts, formats, and writes the arguments to the compressed file under
M
Mark Adler 已提交
1378 1379
   control of the format string, as in fprintf.  gzprintf returns the number of
   uncompressed bytes actually written, or 0 in case of error.  The number of
M
Mark Adler 已提交
1380
   uncompressed bytes written is limited to 8191, or one less than the buffer
M
Mark Adler 已提交
1381 1382 1383 1384 1385
   size given to gzbuffer().  The caller should assure that this limit is not
   exceeded.  If it is exceeded, then gzprintf() will return an error (0) with
   nothing written.  In this case, there may also be a buffer overflow with
   unpredictable consequences, which is possible only if zlib was compiled with
   the insecure functions sprintf() or vsprintf() because the secure snprintf()
M
Mark Adler 已提交
1386
   or vsnprintf() functions were not available.  This can be determined using
M
Mark Adler 已提交
1387
   zlibCompileFlags().
M
Mark Adler 已提交
1388 1389
*/

M
Mark Adler 已提交
1390
ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s));
M
Mark Adler 已提交
1391
/*
M
Mark Adler 已提交
1392
     Writes the given null-terminated string to the compressed file, excluding
M
Mark Adler 已提交
1393
   the terminating null character.
M
Mark Adler 已提交
1394 1395

     gzputs returns the number of characters written, or -1 in case of error.
M
Mark Adler 已提交
1396 1397
*/

M
Mark Adler 已提交
1398
ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len));
M
Mark Adler 已提交
1399
/*
M
Mark Adler 已提交
1400 1401 1402 1403 1404 1405 1406 1407 1408
     Reads bytes from the compressed file until len-1 characters are read, or a
   newline character is read and transferred to buf, or an end-of-file
   condition is encountered.  If any characters are read or if len == 1, the
   string is terminated with a null character.  If no characters are read due
   to an end-of-file or len < 1, then the buffer is left untouched.

     gzgets returns buf which is a null-terminated string, or it returns NULL
   for end-of-file or in case of error.  If there was an error, the contents at
   buf are indeterminate.
M
Mark Adler 已提交
1409 1410
*/

M
Mark Adler 已提交
1411
ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c));
M
Mark Adler 已提交
1412
/*
M
Mark Adler 已提交
1413 1414
     Writes c, converted to an unsigned char, into the compressed file.  gzputc
   returns the value that was written, or -1 in case of error.
M
Mark Adler 已提交
1415 1416
*/

1417
ZEXTERN int ZEXPORT gzgetc OF((gzFile file));
1418
/*
M
Mark Adler 已提交
1419
     Reads one byte from the compressed file.  gzgetc returns this byte or -1
1420 1421 1422 1423
   in case of end of file or error.  This is implemented as a macro for speed.
   As such, it does not do all of the checking the other functions do.  I.e.
   it does not check to see if file is NULL, nor whether the structure file
   points to has been clobbered or not.
M
Mark Adler 已提交
1424 1425
*/

M
Mark Adler 已提交
1426
ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file));
M
Mark Adler 已提交
1427
/*
M
Mark Adler 已提交
1428 1429 1430 1431 1432 1433 1434 1435
     Push one character back onto the stream to be read as the first character
   on the next read.  At least one character of push-back is allowed.
   gzungetc() returns the character pushed, or -1 on failure.  gzungetc() will
   fail if c is -1, and may fail if a character has been pushed but not read
   yet.  If gzungetc is used immediately after gzopen or gzdopen, at least the
   output buffer size of pushed characters is allowed.  (See gzbuffer above.)
   The pushed character will be discarded if the stream is repositioned with
   gzseek() or gzrewind().
M
Mark Adler 已提交
1436 1437
*/

M
Mark Adler 已提交
1438
ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush));
M
Mark Adler 已提交
1439
/*
M
Mark Adler 已提交
1440 1441
     Flushes all pending output into the compressed file.  The parameter flush
   is as in the deflate() function.  The return value is the zlib error number
M
Mark Adler 已提交
1442
   (see function gzerror below).  gzflush is only permitted when writing.
M
Mark Adler 已提交
1443 1444 1445 1446

     If the flush parameter is Z_FINISH, the remaining data is written and the
   gzip stream is completed in the output.  If gzwrite() is called again, a new
   gzip stream will be started in the output.  gzread() is able to read such
M
Mark Adler 已提交
1447
   concatenated gzip streams.
M
Mark Adler 已提交
1448 1449 1450

     gzflush should be called only when strictly necessary because it will
   degrade compression if called too often.
M
Mark Adler 已提交
1451 1452
*/

M
Mark Adler 已提交
1453
/*
M
Mark Adler 已提交
1454 1455
ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file,
                                   z_off_t offset, int whence));
M
Mark Adler 已提交
1456

M
Mark Adler 已提交
1457 1458 1459
     Sets the starting position for the next gzread or gzwrite on the given
   compressed file.  The offset represents a number of bytes in the
   uncompressed data stream.  The whence parameter is defined as in lseek(2);
M
Mark Adler 已提交
1460
   the value SEEK_END is not supported.
M
Mark Adler 已提交
1461

M
Mark Adler 已提交
1462
     If the file is opened for reading, this function is emulated but can be
M
Mark Adler 已提交
1463
   extremely slow.  If the file is opened for writing, only forward seeks are
M
Mark Adler 已提交
1464 1465 1466
   supported; gzseek then compresses a sequence of zeroes up to the new
   starting position.

M
Mark Adler 已提交
1467
     gzseek returns the resulting offset location as measured in bytes from
M
Mark Adler 已提交
1468 1469 1470 1471 1472
   the beginning of the uncompressed stream, or -1 in case of error, in
   particular if the file is opened for writing and the new starting position
   would be before the current position.
*/

M
Mark Adler 已提交
1473
ZEXTERN int ZEXPORT    gzrewind OF((gzFile file));
M
Mark Adler 已提交
1474 1475 1476
/*
     Rewinds the given file. This function is supported only for reading.

M
Mark Adler 已提交
1477
     gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET)
M
Mark Adler 已提交
1478 1479 1480
*/

/*
M
Mark Adler 已提交
1481 1482
ZEXTERN z_off_t ZEXPORT    gztell OF((gzFile file));

M
Mark Adler 已提交
1483 1484 1485 1486
     Returns the starting position for the next gzread or gzwrite on the given
   compressed file.  This position represents a number of bytes in the
   uncompressed data stream, and is zero when starting, even if appending or
   reading a gzip stream from the middle of a file using gzdopen().
M
Mark Adler 已提交
1487

M
Mark Adler 已提交
1488
     gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)
M
Mark Adler 已提交
1489 1490
*/

M
Mark Adler 已提交
1491 1492 1493
/*
ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile file));

M
Mark Adler 已提交
1494
     Returns the current offset in the file being read or written.  This offset
M
Mark Adler 已提交
1495
   includes the count of bytes that precede the gzip stream, for example when
M
Mark Adler 已提交
1496
   appending or when using gzdopen() for reading.  When reading, the offset
M
Mark Adler 已提交
1497 1498
   does not include as yet unused buffered input.  This information can be used
   for a progress indicator.  On error, gzoffset() returns -1.
M
Mark Adler 已提交
1499 1500
*/

M
Mark Adler 已提交
1501
ZEXTERN int ZEXPORT gzeof OF((gzFile file));
M
Mark Adler 已提交
1502
/*
M
Mark Adler 已提交
1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513
     Returns true (1) if the end-of-file indicator has been set while reading,
   false (0) otherwise.  Note that the end-of-file indicator is set only if the
   read tried to go past the end of the input, but came up short.  Therefore,
   just like feof(), gzeof() may return false even if there is no more data to
   read, in the event that the last read request was for the exact number of
   bytes remaining in the input file.  This will happen if the input file size
   is an exact multiple of the buffer size.

     If gzeof() returns true, then the read functions will return no more data,
   unless the end-of-file indicator is reset by gzclearerr() and the input file
   has grown since the previous end of file was detected.
M
Mark Adler 已提交
1514 1515
*/

M
Mark Adler 已提交
1516 1517
ZEXTERN int ZEXPORT gzdirect OF((gzFile file));
/*
M
Mark Adler 已提交
1518
     Returns true (1) if file is being copied directly while reading, or false
1519
   (0) if file is a gzip stream being decompressed.
M
Mark Adler 已提交
1520 1521 1522 1523 1524 1525 1526 1527

     If the input file is empty, gzdirect() will return true, since the input
   does not contain a gzip stream.

     If gzdirect() is used immediately after gzopen() or gzdopen() it will
   cause buffers to be allocated to allow reading the file to determine if it
   is a gzip file.  Therefore if gzbuffer() is used, it should be called before
   gzdirect().
1528 1529 1530 1531 1532 1533 1534

     When writing, gzdirect() returns true (1) if transparent writing was
   requested ("wT" for the gzopen() mode), or false (0) otherwise.  (Note:
   gzdirect() is not needed when writing.  Transparent writing must be
   explicitly requested, so the application already knows the answer.  When
   linking statically, using gzdirect() will include all of the zlib code for
   gzip file reading and decompression, which may not be desired.)
M
Mark Adler 已提交
1535 1536
*/

M
Mark Adler 已提交
1537
ZEXTERN int ZEXPORT    gzclose OF((gzFile file));
M
Mark Adler 已提交
1538
/*
M
Mark Adler 已提交
1539
     Flushes all pending output if necessary, closes the compressed file and
M
Mark Adler 已提交
1540 1541 1542 1543 1544 1545
   deallocates the (de)compression state.  Note that once file is closed, you
   cannot call gzerror with file, since its structures have been deallocated.
   gzclose must not be called more than once on the same file, just as free
   must not be called more than once on the same allocation.

     gzclose will return Z_STREAM_ERROR if file is not valid, Z_ERRNO on a
1546 1547
   file operation error, Z_MEM_ERROR if out of memory, Z_BUF_ERROR if the
   last read ended in the middle of a gzip stream, or Z_OK on success.
M
Mark Adler 已提交
1548 1549
*/

M
Mark Adler 已提交
1550 1551 1552
ZEXTERN int ZEXPORT gzclose_r OF((gzFile file));
ZEXTERN int ZEXPORT gzclose_w OF((gzFile file));
/*
M
Mark Adler 已提交
1553
     Same as gzclose(), but gzclose_r() is only for use when reading, and
M
Mark Adler 已提交
1554 1555 1556 1557 1558 1559
   gzclose_w() is only for use when writing or appending.  The advantage to
   using these instead of gzclose() is that they avoid linking in zlib
   compression or decompression code that is not used when only reading or only
   writing respectively.  If gzclose() is used, then both compression and
   decompression code will be included the application when linking to a static
   zlib library.
M
Mark Adler 已提交
1560 1561
*/

M
Mark Adler 已提交
1562
ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum));
M
Mark Adler 已提交
1563
/*
M
Mark Adler 已提交
1564 1565 1566 1567
     Returns the error message for the last error which occurred on the given
   compressed file.  errnum is set to zlib error number.  If an error occurred
   in the file system and not in the compression library, errnum is set to
   Z_ERRNO and the application may consult errno to get the exact error code.
M
Mark Adler 已提交
1568

M
Mark Adler 已提交
1569 1570 1571 1572
     The application must not modify the returned string.  Future calls to
   this function may invalidate the previously returned string.  If file is
   closed, then the string previously returned by gzerror will no longer be
   available.
M
Mark Adler 已提交
1573 1574 1575

     gzerror() should be used to distinguish errors from end-of-file for those
   functions above that do not distinguish those cases in their return values.
M
Mark Adler 已提交
1576 1577
*/

M
Mark Adler 已提交
1578 1579
ZEXTERN void ZEXPORT gzclearerr OF((gzFile file));
/*
M
Mark Adler 已提交
1580 1581
     Clears the error and end-of-file flags for file.  This is analogous to the
   clearerr() function in stdio.  This is useful for continuing to read a gzip
M
Mark Adler 已提交
1582 1583 1584
   file that is being written concurrently.
*/

1585
#endif /* !Z_SOLO */
M
Mark Adler 已提交
1586

M
Mark Adler 已提交
1587 1588 1589 1590
                        /* checksum functions */

/*
     These functions are not related to compression but are exported
M
Mark Adler 已提交
1591 1592
   anyway because they might be useful in applications using the compression
   library.
M
Mark Adler 已提交
1593 1594
*/

M
Mark Adler 已提交
1595
ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len));
M
Mark Adler 已提交
1596 1597
/*
     Update a running Adler-32 checksum with the bytes buf[0..len-1] and
M
Mark Adler 已提交
1598 1599 1600 1601 1602 1603 1604
   return the updated checksum.  If buf is Z_NULL, this function returns the
   required initial value for the checksum.

     An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
   much faster.

   Usage example:
M
Mark Adler 已提交
1605 1606 1607 1608 1609 1610 1611 1612 1613

     uLong adler = adler32(0L, Z_NULL, 0);

     while (read_buffer(buffer, length) != EOF) {
       adler = adler32(adler, buffer, length);
     }
     if (adler != original_adler) error();
*/

M
Mark Adler 已提交
1614
/*
M
Mark Adler 已提交
1615
ZEXTERN uLong ZEXPORT adler32_combine OF((uLong adler1, uLong adler2,
M
Mark Adler 已提交
1616
                                          z_off_t len2));
M
Mark Adler 已提交
1617

M
Mark Adler 已提交
1618 1619 1620
     Combine two Adler-32 checksums into one.  For two sequences of bytes, seq1
   and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for
   each, adler1 and adler2.  adler32_combine() returns the Adler-32 checksum of
M
Mark Adler 已提交
1621 1622 1623
   seq1 and seq2 concatenated, requiring only adler1, adler2, and len2.  Note
   that the z_off_t type (like off_t) is a signed integer.  If len2 is
   negative, the result has no meaning or utility.
M
Mark Adler 已提交
1624 1625
*/

M
Mark Adler 已提交
1626
ZEXTERN uLong ZEXPORT crc32   OF((uLong crc, const Bytef *buf, uInt len));
M
Mark Adler 已提交
1627
/*
M
Mark Adler 已提交
1628
     Update a running CRC-32 with the bytes buf[0..len-1] and return the
M
Mark Adler 已提交
1629
   updated CRC-32.  If buf is Z_NULL, this function returns the required
1630 1631
   initial value for the crc.  Pre- and post-conditioning (one's complement) is
   performed within this function so it shouldn't be done by the application.
M
Mark Adler 已提交
1632

M
Mark Adler 已提交
1633 1634 1635 1636 1637 1638 1639 1640 1641 1642
   Usage example:

     uLong crc = crc32(0L, Z_NULL, 0);

     while (read_buffer(buffer, length) != EOF) {
       crc = crc32(crc, buffer, length);
     }
     if (crc != original_crc) error();
*/

M
Mark Adler 已提交
1643
/*
M
Mark Adler 已提交
1644
ZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2));
M
Mark Adler 已提交
1645 1646 1647 1648 1649 1650 1651 1652

     Combine two CRC-32 check values into one.  For two sequences of bytes,
   seq1 and seq2 with lengths len1 and len2, CRC-32 check values were
   calculated for each, crc1 and crc2.  crc32_combine() returns the CRC-32
   check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and
   len2.
*/

M
Mark Adler 已提交
1653 1654 1655 1656 1657 1658

                        /* various hacks, don't look :) */

/* deflateInit and inflateInit are macros to allow checking the zlib version
 * and the compiler's view of z_stream:
 */
M
Mark Adler 已提交
1659
ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level,
M
Mark Adler 已提交
1660
                                     const char *version, int stream_size));
M
Mark Adler 已提交
1661 1662 1663 1664 1665 1666 1667 1668
ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm,
                                     const char *version, int stream_size));
ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int  level, int  method,
                                      int windowBits, int memLevel,
                                      int strategy, const char *version,
                                      int stream_size));
ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int  windowBits,
                                      const char *version, int stream_size));
M
Mark Adler 已提交
1669
ZEXTERN int ZEXPORT inflateBackInit_ OF((z_streamp strm, int windowBits,
M
Mark Adler 已提交
1670 1671 1672
                                         unsigned char FAR *window,
                                         const char *version,
                                         int stream_size));
M
Mark Adler 已提交
1673
#define deflateInit(strm, level) \
M
Mark Adler 已提交
1674
        deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream))
M
Mark Adler 已提交
1675
#define inflateInit(strm) \
M
Mark Adler 已提交
1676
        inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream))
M
Mark Adler 已提交
1677 1678
#define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
        deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
M
Mark Adler 已提交
1679
                      (strategy), ZLIB_VERSION, (int)sizeof(z_stream))
M
Mark Adler 已提交
1680
#define inflateInit2(strm, windowBits) \
M
Mark Adler 已提交
1681 1682
        inflateInit2_((strm), (windowBits), ZLIB_VERSION, \
                      (int)sizeof(z_stream))
M
Mark Adler 已提交
1683 1684
#define inflateBackInit(strm, windowBits, window) \
        inflateBackInit_((strm), (windowBits), (window), \
M
Mark Adler 已提交
1685
                      ZLIB_VERSION, (int)sizeof(z_stream))
M
Mark Adler 已提交
1686

1687 1688
#ifndef Z_SOLO

1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700
/* gzgetc() macro and its supporting function and exposed data structure.  Note
 * that the real internal state is much larger than the exposed structure.
 * This abbreviated structure exposes just enough for the gzgetc() macro.  The
 * user should not mess with these exposed elements, since their names or
 * behavior could change in the future, perhaps even capriciously.  They can
 * only be used by the gzgetc() macro.  You have been warned.
 */
struct gzFile_s {
    unsigned have;
    unsigned char *next;
    z_off64_t pos;
};
1701
ZEXTERN int ZEXPORT gzgetc_ OF((gzFile file));  /* backward compatibility */
1702 1703 1704
#ifdef Z_PREFIX_SET
#  undef z_gzgetc
#  define z_gzgetc(g) \
M
Mark Adler 已提交
1705
          ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : (gzgetc)(g))
1706 1707
#else
#  define gzgetc(g) \
M
Mark Adler 已提交
1708
          ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : (gzgetc)(g))
1709
#endif
1710

M
Mark Adler 已提交
1711 1712 1713 1714 1715 1716
/* provide 64-bit offset functions if _LARGEFILE64_SOURCE defined, and/or
 * change the regular functions to 64 bits if _FILE_OFFSET_BITS is 64 (if
 * both are true, the application gets the *64 functions, and the regular
 * functions are changed to 64 bits) -- in case these are set on systems
 * without large file support, _LFS64_LARGEFILE must also be true
 */
1717
#ifdef Z_LARGE64
M
Mark Adler 已提交
1718
   ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *));
M
Mark Adler 已提交
1719 1720 1721 1722 1723
   ZEXTERN z_off64_t ZEXPORT gzseek64 OF((gzFile, z_off64_t, int));
   ZEXTERN z_off64_t ZEXPORT gztell64 OF((gzFile));
   ZEXTERN z_off64_t ZEXPORT gzoffset64 OF((gzFile));
   ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off64_t));
   ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off64_t));
M
Mark Adler 已提交
1724 1725
#endif

1726
#if !defined(ZLIB_INTERNAL) && defined(Z_WANT64)
M
Mark Adler 已提交
1727 1728 1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741
#  ifdef Z_PREFIX_SET
#    define z_gzopen z_gzopen64
#    define z_gzseek z_gzseek64
#    define z_gztell z_gztell64
#    define z_gzoffset z_gzoffset64
#    define z_adler32_combine z_adler32_combine64
#    define z_crc32_combine z_crc32_combine64
#  else
#    define gzopen gzopen64
#    define gzseek gzseek64
#    define gztell gztell64
#    define gzoffset gzoffset64
#    define adler32_combine adler32_combine64
#    define crc32_combine crc32_combine64
#  endif
1742
#  ifndef Z_LARGE64
M
Mark Adler 已提交
1743
     ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *));
M
Mark Adler 已提交
1744 1745 1746 1747 1748
     ZEXTERN z_off_t ZEXPORT gzseek64 OF((gzFile, z_off_t, int));
     ZEXTERN z_off_t ZEXPORT gztell64 OF((gzFile));
     ZEXTERN z_off_t ZEXPORT gzoffset64 OF((gzFile));
     ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off_t));
     ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off_t));
M
Mark Adler 已提交
1749
#  endif
M
Mark Adler 已提交
1750 1751 1752 1753
#else
   ZEXTERN gzFile ZEXPORT gzopen OF((const char *, const char *));
   ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile, z_off_t, int));
   ZEXTERN z_off_t ZEXPORT gztell OF((gzFile));
M
Mark Adler 已提交
1754
   ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile));
M
Mark Adler 已提交
1755 1756 1757 1758
   ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t));
   ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t));
#endif

1759 1760 1761 1762 1763 1764 1765
#else /* Z_SOLO */

   ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t));
   ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t));

#endif /* !Z_SOLO */

M
Mark Adler 已提交
1766
/* undocumented functions */
M
Mark Adler 已提交
1767
ZEXTERN const char   * ZEXPORT zError           OF((int));
M
Mark Adler 已提交
1768
ZEXTERN int            ZEXPORT inflateSyncPoint OF((z_streamp));
1769
ZEXTERN const z_crc_t FAR * ZEXPORT get_crc_table    OF((void));
M
Mark Adler 已提交
1770
ZEXTERN int            ZEXPORT inflateUndermine OF((z_streamp, int));
1771
ZEXTERN int            ZEXPORT inflateValidate OF((z_streamp, int));
M
Mark Adler 已提交
1772
ZEXTERN unsigned long  ZEXPORT inflateCodesUsed OF ((z_streamp));
1773
ZEXTERN int            ZEXPORT inflateResetKeep OF((z_streamp));
1774
ZEXTERN int            ZEXPORT deflateResetKeep OF((z_streamp));
1775
#if (defined(_WIN32) || defined(__CYGWIN__)) && !defined(Z_SOLO)
1776
ZEXTERN gzFile         ZEXPORT gzopen_w OF((const wchar_t *path,
1777 1778
                                            const char *mode));
#endif
1779 1780
#if defined(STDC) || defined(Z_HAVE_STDARG_H)
#  ifndef Z_SOLO
M
Mark Adler 已提交
1781 1782 1783
ZEXTERN int            ZEXPORTVA gzvprintf Z_ARG((gzFile file,
                                                  const char *format,
                                                  va_list va));
1784 1785
#  endif
#endif
M
Mark Adler 已提交
1786

M
Mark Adler 已提交
1787 1788 1789 1790
#ifdef __cplusplus
}
#endif

M
Mark Adler 已提交
1791
#endif /* ZLIB_H */