linux-old/include/linux/zlib.h
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   1/* zlib.h -- interface of the 'zlib' general purpose compression library
   2  version 1.1.3, July 9th, 1998
   3
   4  Copyright (C) 1995-1998 Jean-loup Gailly and Mark Adler
   5
   6  This software is provided 'as-is', without any express or implied
   7  warranty.  In no event will the authors be held liable for any damages
   8  arising from the use of this software.
   9
  10  Permission is granted to anyone to use this software for any purpose,
  11  including commercial applications, and to alter it and redistribute it
  12  freely, subject to the following restrictions:
  13
  14  1. The origin of this software must not be misrepresented; you must not
  15     claim that you wrote the original software. If you use this software
  16     in a product, an acknowledgment in the product documentation would be
  17     appreciated but is not required.
  18  2. Altered source versions must be plainly marked as such, and must not be
  19     misrepresented as being the original software.
  20  3. This notice may not be removed or altered from any source distribution.
  21
  22  Jean-loup Gailly        Mark Adler
  23  jloup@gzip.org          madler@alumni.caltech.edu
  24
  25
  26  The data format used by the zlib library is described by RFCs (Request for
  27  Comments) 1950 to 1952 in the files ftp://ds.internic.net/rfc/rfc1950.txt
  28  (zlib format), rfc1951.txt (deflate format) and rfc1952.txt (gzip format).
  29*/
  30
  31#ifndef _ZLIB_H
  32#define _ZLIB_H
  33
  34#include <linux/zconf.h>
  35
  36#ifdef __cplusplus
  37extern "C" {
  38#endif
  39
  40#define ZLIB_VERSION "1.1.3"
  41
  42/* 
  43     The 'zlib' compression library provides in-memory compression and
  44  decompression functions, including integrity checks of the uncompressed
  45  data.  This version of the library supports only one compression method
  46  (deflation) but other algorithms will be added later and will have the same
  47  stream interface.
  48
  49     Compression can be done in a single step if the buffers are large
  50  enough (for example if an input file is mmap'ed), or can be done by
  51  repeated calls of the compression function.  In the latter case, the
  52  application must provide more input and/or consume the output
  53  (providing more output space) before each call.
  54
  55     The library also supports reading and writing files in gzip (.gz) format
  56  with an interface similar to that of stdio.
  57
  58     The library does not install any signal handler. The decoder checks
  59  the consistency of the compressed data, so the library should never
  60  crash even in case of corrupted input.
  61*/
  62
  63typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size));
  64typedef void   (*free_func)  OF((voidpf opaque, voidpf address));
  65
  66struct internal_state;
  67
  68typedef struct z_stream_s {
  69    Bytef    *next_in;  /* next input byte */
  70    uInt     avail_in;  /* number of bytes available at next_in */
  71    uLong    total_in;  /* total nb of input bytes read so far */
  72
  73    Bytef    *next_out; /* next output byte should be put there */
  74    uInt     avail_out; /* remaining free space at next_out */
  75    uLong    total_out; /* total nb of bytes output so far */
  76
  77    char     *msg;      /* last error message, NULL if no error */
  78    struct internal_state FAR *state; /* not visible by applications */
  79
  80    void     *workspace; /* memory allocated for this stream */
  81
  82    int     data_type;  /* best guess about the data type: ascii or binary */
  83    uLong   adler;      /* adler32 value of the uncompressed data */
  84    uLong   reserved;   /* reserved for future use */
  85} z_stream;
  86
  87typedef z_stream FAR *z_streamp;
  88
  89/*
  90   The application must update next_in and avail_in when avail_in has
  91   dropped to zero. It must update next_out and avail_out when avail_out
  92   has dropped to zero. The application must initialize zalloc, zfree and
  93   opaque before calling the init function. All other fields are set by the
  94   compression library and must not be updated by the application.
  95
  96   The opaque value provided by the application will be passed as the first
  97   parameter for calls of zalloc and zfree. This can be useful for custom
  98   memory management. The compression library attaches no meaning to the
  99   opaque value.
 100
 101   zalloc must return Z_NULL if there is not enough memory for the object.
 102   If zlib is used in a multi-threaded application, zalloc and zfree must be
 103   thread safe.
 104
 105   On 16-bit systems, the functions zalloc and zfree must be able to allocate
 106   exactly 65536 bytes, but will not be required to allocate more than this
 107   if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS,
 108   pointers returned by zalloc for objects of exactly 65536 bytes *must*
 109   have their offset normalized to zero. The default allocation function
 110   provided by this library ensures this (see zutil.c). To reduce memory
 111   requirements and avoid any allocation of 64K objects, at the expense of
 112   compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h).
 113
 114   The fields total_in and total_out can be used for statistics or
 115   progress reports. After compression, total_in holds the total size of
 116   the uncompressed data and may be saved for use in the decompressor
 117   (particularly if the decompressor wants to decompress everything in
 118   a single step).
 119*/
 120
 121                        /* constants */
 122
 123#define Z_NO_FLUSH      0
 124#define Z_PARTIAL_FLUSH 1 /* will be removed, use Z_SYNC_FLUSH instead */
 125#define Z_PACKET_FLUSH  2
 126#define Z_SYNC_FLUSH    3
 127#define Z_FULL_FLUSH    4
 128#define Z_FINISH        5
 129/* Allowed flush values; see deflate() below for details */
 130
 131#define Z_OK            0
 132#define Z_STREAM_END    1
 133#define Z_NEED_DICT     2
 134#define Z_ERRNO        (-1)
 135#define Z_STREAM_ERROR (-2)
 136#define Z_DATA_ERROR   (-3)
 137#define Z_MEM_ERROR    (-4)
 138#define Z_BUF_ERROR    (-5)
 139#define Z_VERSION_ERROR (-6)
 140/* Return codes for the compression/decompression functions. Negative
 141 * values are errors, positive values are used for special but normal events.
 142 */
 143
 144#define Z_NO_COMPRESSION         0
 145#define Z_BEST_SPEED             1
 146#define Z_BEST_COMPRESSION       9
 147#define Z_DEFAULT_COMPRESSION  (-1)
 148/* compression levels */
 149
 150#define Z_FILTERED            1
 151#define Z_HUFFMAN_ONLY        2
 152#define Z_DEFAULT_STRATEGY    0
 153/* compression strategy; see deflateInit2() below for details */
 154
 155#define Z_BINARY   0
 156#define Z_ASCII    1
 157#define Z_UNKNOWN  2
 158/* Possible values of the data_type field */
 159
 160#define Z_DEFLATED   8
 161/* The deflate compression method (the only one supported in this version) */
 162
 163#define Z_NULL  0  /* for initializing zalloc, zfree, opaque */
 164
 165                        /* basic functions */
 166
 167ZEXTERN const char * ZEXPORT zlib_zlibVersion OF((void));
 168/* The application can compare zlibVersion and ZLIB_VERSION for consistency.
 169   If the first character differs, the library code actually used is
 170   not compatible with the zlib.h header file used by the application.
 171   This check is automatically made by deflateInit and inflateInit.
 172 */
 173
 174ZEXTERN int ZEXPORT zlib_deflate_workspacesize OF((void));
 175/*
 176   Returns the number of bytes that needs to be allocated for a per-
 177   stream workspace.  A pointer to this number of bytes should be
 178   returned in stream->workspace before calling zlib_deflateInit().
 179*/
 180
 181/* 
 182ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level));
 183
 184     Initializes the internal stream state for compression. The fields
 185   zalloc, zfree and opaque must be initialized before by the caller.
 186   If zalloc and zfree are set to Z_NULL, deflateInit updates them to
 187   use default allocation functions.
 188
 189     The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
 190   1 gives best speed, 9 gives best compression, 0 gives no compression at
 191   all (the input data is simply copied a block at a time).
 192   Z_DEFAULT_COMPRESSION requests a default compromise between speed and
 193   compression (currently equivalent to level 6).
 194
 195     deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not
 196   enough memory, Z_STREAM_ERROR if level is not a valid compression level,
 197   Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
 198   with the version assumed by the caller (ZLIB_VERSION).
 199   msg is set to null if there is no error message.  deflateInit does not
 200   perform any compression: this will be done by deflate().
 201*/
 202
 203
 204ZEXTERN int ZEXPORT zlib_deflate OF((z_streamp strm, int flush));
 205/*
 206    deflate compresses as much data as possible, and stops when the input
 207  buffer becomes empty or the output buffer becomes full. It may introduce some
 208  output latency (reading input without producing any output) except when
 209  forced to flush.
 210
 211    The detailed semantics are as follows. deflate performs one or both of the
 212  following actions:
 213
 214  - Compress more input starting at next_in and update next_in and avail_in
 215    accordingly. If not all input can be processed (because there is not
 216    enough room in the output buffer), next_in and avail_in are updated and
 217    processing will resume at this point for the next call of deflate().
 218
 219  - Provide more output starting at next_out and update next_out and avail_out
 220    accordingly. This action is forced if the parameter flush is non zero.
 221    Forcing flush frequently degrades the compression ratio, so this parameter
 222    should be set only when necessary (in interactive applications).
 223    Some output may be provided even if flush is not set.
 224
 225  Before the call of deflate(), the application should ensure that at least
 226  one of the actions is possible, by providing more input and/or consuming
 227  more output, and updating avail_in or avail_out accordingly; avail_out
 228  should never be zero before the call. The application can consume the
 229  compressed output when it wants, for example when the output buffer is full
 230  (avail_out == 0), or after each call of deflate(). If deflate returns Z_OK
 231  and with zero avail_out, it must be called again after making room in the
 232  output buffer because there might be more output pending.
 233
 234    If the parameter flush is set to Z_SYNC_FLUSH, all pending output is
 235  flushed to the output buffer and the output is aligned on a byte boundary, so
 236  that the decompressor can get all input data available so far. (In particular
 237  avail_in is zero after the call if enough output space has been provided
 238  before the call.)  Flushing may degrade compression for some compression
 239  algorithms and so it should be used only when necessary.
 240
 241    If flush is set to Z_FULL_FLUSH, all output is flushed as with
 242  Z_SYNC_FLUSH, and the compression state is reset so that decompression can
 243  restart from this point if previous compressed data has been damaged or if
 244  random access is desired. Using Z_FULL_FLUSH too often can seriously degrade
 245  the compression.
 246
 247    If deflate returns with avail_out == 0, this function must be called again
 248  with the same value of the flush parameter and more output space (updated
 249  avail_out), until the flush is complete (deflate returns with non-zero
 250  avail_out).
 251
 252    If the parameter flush is set to Z_FINISH, pending input is processed,
 253  pending output is flushed and deflate returns with Z_STREAM_END if there
 254  was enough output space; if deflate returns with Z_OK, this function must be
 255  called again with Z_FINISH and more output space (updated avail_out) but no
 256  more input data, until it returns with Z_STREAM_END or an error. After
 257  deflate has returned Z_STREAM_END, the only possible operations on the
 258  stream are deflateReset or deflateEnd.
 259  
 260    Z_FINISH can be used immediately after deflateInit if all the compression
 261  is to be done in a single step. In this case, avail_out must be at least
 262  0.1% larger than avail_in plus 12 bytes.  If deflate does not return
 263  Z_STREAM_END, then it must be called again as described above.
 264
 265    deflate() sets strm->adler to the adler32 checksum of all input read
 266  so far (that is, total_in bytes).
 267
 268    deflate() may update data_type if it can make a good guess about
 269  the input data type (Z_ASCII or Z_BINARY). In doubt, the data is considered
 270  binary. This field is only for information purposes and does not affect
 271  the compression algorithm in any manner.
 272
 273    deflate() returns Z_OK if some progress has been made (more input
 274  processed or more output produced), Z_STREAM_END if all input has been
 275  consumed and all output has been produced (only when flush is set to
 276  Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
 277  if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible
 278  (for example avail_in or avail_out was zero).
 279*/
 280
 281
 282ZEXTERN int ZEXPORT zlib_deflateEnd OF((z_streamp strm));
 283/*
 284     All dynamically allocated data structures for this stream are freed.
 285   This function discards any unprocessed input and does not flush any
 286   pending output.
 287
 288     deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
 289   stream state was inconsistent, Z_DATA_ERROR if the stream was freed
 290   prematurely (some input or output was discarded). In the error case,
 291   msg may be set but then points to a static string (which must not be
 292   deallocated).
 293*/
 294
 295
 296ZEXTERN int ZEXPORT zlib_inflate_workspacesize OF((void));
 297/*
 298   Returns the number of bytes that needs to be allocated for a per-
 299   stream workspace.  A pointer to this number of bytes should be
 300   returned in stream->workspace before calling zlib_inflateInit().
 301*/
 302
 303/* 
 304ZEXTERN int ZEXPORT zlib_inflateInit OF((z_streamp strm));
 305
 306     Initializes the internal stream state for decompression. The fields
 307   next_in, avail_in, and workspace must be initialized before by
 308   the caller. If next_in is not Z_NULL and avail_in is large enough (the exact
 309   value depends on the compression method), inflateInit determines the
 310   compression method from the zlib header and allocates all data structures
 311   accordingly; otherwise the allocation will be deferred to the first call of
 312   inflate.  If zalloc and zfree are set to Z_NULL, inflateInit updates them to
 313   use default allocation functions.
 314
 315     inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
 316   memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
 317   version assumed by the caller.  msg is set to null if there is no error
 318   message. inflateInit does not perform any decompression apart from reading
 319   the zlib header if present: this will be done by inflate().  (So next_in and
 320   avail_in may be modified, but next_out and avail_out are unchanged.)
 321*/
 322
 323
 324ZEXTERN int ZEXPORT zlib_inflate OF((z_streamp strm, int flush));
 325/*
 326    inflate decompresses as much data as possible, and stops when the input
 327  buffer becomes empty or the output buffer becomes full. It may some
 328  introduce some output latency (reading input without producing any output)
 329  except when forced to flush.
 330
 331  The detailed semantics are as follows. inflate performs one or both of the
 332  following actions:
 333
 334  - Decompress more input starting at next_in and update next_in and avail_in
 335    accordingly. If not all input can be processed (because there is not
 336    enough room in the output buffer), next_in is updated and processing
 337    will resume at this point for the next call of inflate().
 338
 339  - Provide more output starting at next_out and update next_out and avail_out
 340    accordingly.  inflate() provides as much output as possible, until there
 341    is no more input data or no more space in the output buffer (see below
 342    about the flush parameter).
 343
 344  Before the call of inflate(), the application should ensure that at least
 345  one of the actions is possible, by providing more input and/or consuming
 346  more output, and updating the next_* and avail_* values accordingly.
 347  The application can consume the uncompressed output when it wants, for
 348  example when the output buffer is full (avail_out == 0), or after each
 349  call of inflate(). If inflate returns Z_OK and with zero avail_out, it
 350  must be called again after making room in the output buffer because there
 351  might be more output pending.
 352
 353    If the parameter flush is set to Z_SYNC_FLUSH, inflate flushes as much
 354  output as possible to the output buffer. The flushing behavior of inflate is
 355  not specified for values of the flush parameter other than Z_SYNC_FLUSH
 356  and Z_FINISH, but the current implementation actually flushes as much output
 357  as possible anyway.
 358
 359    inflate() should normally be called until it returns Z_STREAM_END or an
 360  error. However if all decompression is to be performed in a single step
 361  (a single call of inflate), the parameter flush should be set to
 362  Z_FINISH. In this case all pending input is processed and all pending
 363  output is flushed; avail_out must be large enough to hold all the
 364  uncompressed data. (The size of the uncompressed data may have been saved
 365  by the compressor for this purpose.) The next operation on this stream must
 366  be inflateEnd to deallocate the decompression state. The use of Z_FINISH
 367  is never required, but can be used to inform inflate that a faster routine
 368  may be used for the single inflate() call.
 369
 370     If a preset dictionary is needed at this point (see inflateSetDictionary
 371  below), inflate sets strm-adler to the adler32 checksum of the
 372  dictionary chosen by the compressor and returns Z_NEED_DICT; otherwise 
 373  it sets strm->adler to the adler32 checksum of all output produced
 374  so far (that is, total_out bytes) and returns Z_OK, Z_STREAM_END or
 375  an error code as described below. At the end of the stream, inflate()
 376  checks that its computed adler32 checksum is equal to that saved by the
 377  compressor and returns Z_STREAM_END only if the checksum is correct.
 378
 379    inflate() returns Z_OK if some progress has been made (more input processed
 380  or more output produced), Z_STREAM_END if the end of the compressed data has
 381  been reached and all uncompressed output has been produced, Z_NEED_DICT if a
 382  preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
 383  corrupted (input stream not conforming to the zlib format or incorrect
 384  adler32 checksum), Z_STREAM_ERROR if the stream structure was inconsistent
 385  (for example if next_in or next_out was NULL), Z_MEM_ERROR if there was not
 386  enough memory, Z_BUF_ERROR if no progress is possible or if there was not
 387  enough room in the output buffer when Z_FINISH is used. In the Z_DATA_ERROR
 388  case, the application may then call inflateSync to look for a good
 389  compression block.
 390*/
 391
 392
 393ZEXTERN int ZEXPORT zlib_inflateEnd OF((z_streamp strm));
 394/*
 395     All dynamically allocated data structures for this stream are freed.
 396   This function discards any unprocessed input and does not flush any
 397   pending output.
 398
 399     inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state
 400   was inconsistent. In the error case, msg may be set but then points to a
 401   static string (which must not be deallocated).
 402*/
 403
 404                        /* Advanced functions */
 405
 406/*
 407    The following functions are needed only in some special applications.
 408*/
 409
 410/*   
 411ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm,
 412                                     int  level,
 413                                     int  method,
 414                                     int  windowBits,
 415                                     int  memLevel,
 416                                     int  strategy));
 417
 418     This is another version of deflateInit with more compression options. The
 419   fields next_in, zalloc, zfree and opaque must be initialized before by
 420   the caller.
 421
 422     The method parameter is the compression method. It must be Z_DEFLATED in
 423   this version of the library.
 424
 425     The windowBits parameter is the base two logarithm of the window size
 426   (the size of the history buffer).  It should be in the range 8..15 for this
 427   version of the library. Larger values of this parameter result in better
 428   compression at the expense of memory usage. The default value is 15 if
 429   deflateInit is used instead.
 430
 431     The memLevel parameter specifies how much memory should be allocated
 432   for the internal compression state. memLevel=1 uses minimum memory but
 433   is slow and reduces compression ratio; memLevel=9 uses maximum memory
 434   for optimal speed. The default value is 8. See zconf.h for total memory
 435   usage as a function of windowBits and memLevel.
 436
 437     The strategy parameter is used to tune the compression algorithm. Use the
 438   value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
 439   filter (or predictor), or Z_HUFFMAN_ONLY to force Huffman encoding only (no
 440   string match).  Filtered data consists mostly of small values with a
 441   somewhat random distribution. In this case, the compression algorithm is
 442   tuned to compress them better. The effect of Z_FILTERED is to force more
 443   Huffman coding and less string matching; it is somewhat intermediate
 444   between Z_DEFAULT and Z_HUFFMAN_ONLY. The strategy parameter only affects
 445   the compression ratio but not the correctness of the compressed output even
 446   if it is not set appropriately.
 447
 448      deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
 449   memory, Z_STREAM_ERROR if a parameter is invalid (such as an invalid
 450   method). msg is set to null if there is no error message.  deflateInit2 does
 451   not perform any compression: this will be done by deflate().
 452*/
 453                            
 454ZEXTERN int ZEXPORT zlib_deflateSetDictionary OF((z_streamp strm,
 455                                                     const Bytef *dictionary,
 456                                                     uInt  dictLength));
 457/*
 458     Initializes the compression dictionary from the given byte sequence
 459   without producing any compressed output. This function must be called
 460   immediately after deflateInit, deflateInit2 or deflateReset, before any
 461   call of deflate. The compressor and decompressor must use exactly the same
 462   dictionary (see inflateSetDictionary).
 463
 464     The dictionary should consist of strings (byte sequences) that are likely
 465   to be encountered later in the data to be compressed, with the most commonly
 466   used strings preferably put towards the end of the dictionary. Using a
 467   dictionary is most useful when the data to be compressed is short and can be
 468   predicted with good accuracy; the data can then be compressed better than
 469   with the default empty dictionary.
 470
 471     Depending on the size of the compression data structures selected by
 472   deflateInit or deflateInit2, a part of the dictionary may in effect be
 473   discarded, for example if the dictionary is larger than the window size in
 474   deflate or deflate2. Thus the strings most likely to be useful should be
 475   put at the end of the dictionary, not at the front.
 476
 477     Upon return of this function, strm->adler is set to the Adler32 value
 478   of the dictionary; the decompressor may later use this value to determine
 479   which dictionary has been used by the compressor. (The Adler32 value
 480   applies to the whole dictionary even if only a subset of the dictionary is
 481   actually used by the compressor.)
 482
 483     deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
 484   parameter is invalid (such as NULL dictionary) or the stream state is
 485   inconsistent (for example if deflate has already been called for this stream
 486   or if the compression method is bsort). deflateSetDictionary does not
 487   perform any compression: this will be done by deflate().
 488*/
 489
 490ZEXTERN int ZEXPORT zlib_deflateCopy OF((z_streamp dest,
 491                                            z_streamp source));
 492/*
 493     Sets the destination stream as a complete copy of the source stream.
 494
 495     This function can be useful when several compression strategies will be
 496   tried, for example when there are several ways of pre-processing the input
 497   data with a filter. The streams that will be discarded should then be freed
 498   by calling deflateEnd.  Note that deflateCopy duplicates the internal
 499   compression state which can be quite large, so this strategy is slow and
 500   can consume lots of memory.
 501
 502     deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
 503   enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
 504   (such as zalloc being NULL). msg is left unchanged in both source and
 505   destination.
 506*/
 507
 508ZEXTERN int ZEXPORT zlib_deflateReset OF((z_streamp strm));
 509/*
 510     This function is equivalent to deflateEnd followed by deflateInit,
 511   but does not free and reallocate all the internal compression state.
 512   The stream will keep the same compression level and any other attributes
 513   that may have been set by deflateInit2.
 514
 515      deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
 516   stream state was inconsistent (such as zalloc or state being NULL).
 517*/
 518
 519ZEXTERN int ZEXPORT zlib_deflateParams OF((z_streamp strm,
 520                                              int level,
 521                                              int strategy));
 522/*
 523     Dynamically update the compression level and compression strategy.  The
 524   interpretation of level and strategy is as in deflateInit2.  This can be
 525   used to switch between compression and straight copy of the input data, or
 526   to switch to a different kind of input data requiring a different
 527   strategy. If the compression level is changed, the input available so far
 528   is compressed with the old level (and may be flushed); the new level will
 529   take effect only at the next call of deflate().
 530
 531     Before the call of deflateParams, the stream state must be set as for
 532   a call of deflate(), since the currently available input may have to
 533   be compressed and flushed. In particular, strm->avail_out must be non-zero.
 534
 535     deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source
 536   stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR
 537   if strm->avail_out was zero.
 538*/
 539
 540/*   
 541ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm,
 542                                     int  windowBits));
 543
 544     This is another version of inflateInit with an extra parameter. The
 545   fields next_in, avail_in, zalloc, zfree and opaque must be initialized
 546   before by the caller.
 547
 548     The windowBits parameter is the base two logarithm of the maximum window
 549   size (the size of the history buffer).  It should be in the range 8..15 for
 550   this version of the library. The default value is 15 if inflateInit is used
 551   instead. If a compressed stream with a larger window size is given as
 552   input, inflate() will return with the error code Z_DATA_ERROR instead of
 553   trying to allocate a larger window.
 554
 555      inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
 556   memory, Z_STREAM_ERROR if a parameter is invalid (such as a negative
 557   memLevel). msg is set to null if there is no error message.  inflateInit2
 558   does not perform any decompression apart from reading the zlib header if
 559   present: this will be done by inflate(). (So next_in and avail_in may be
 560   modified, but next_out and avail_out are unchanged.)
 561*/
 562
 563ZEXTERN int ZEXPORT zlib_inflateSetDictionary OF((z_streamp strm,
 564                                                     const Bytef *dictionary,
 565                                                     uInt  dictLength));
 566/*
 567     Initializes the decompression dictionary from the given uncompressed byte
 568   sequence. This function must be called immediately after a call of inflate
 569   if this call returned Z_NEED_DICT. The dictionary chosen by the compressor
 570   can be determined from the Adler32 value returned by this call of
 571   inflate. The compressor and decompressor must use exactly the same
 572   dictionary (see deflateSetDictionary).
 573
 574     inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
 575   parameter is invalid (such as NULL dictionary) or the stream state is
 576   inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
 577   expected one (incorrect Adler32 value). inflateSetDictionary does not
 578   perform any decompression: this will be done by subsequent calls of
 579   inflate().
 580*/
 581
 582ZEXTERN int ZEXPORT zlib_inflateSync OF((z_streamp strm));
 583/* 
 584    Skips invalid compressed data until a full flush point (see above the
 585  description of deflate with Z_FULL_FLUSH) can be found, or until all
 586  available input is skipped. No output is provided.
 587
 588    inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR
 589  if no more input was provided, Z_DATA_ERROR if no flush point has been found,
 590  or Z_STREAM_ERROR if the stream structure was inconsistent. In the success
 591  case, the application may save the current current value of total_in which
 592  indicates where valid compressed data was found. In the error case, the
 593  application may repeatedly call inflateSync, providing more input each time,
 594  until success or end of the input data.
 595*/
 596
 597ZEXTERN int ZEXPORT zlib_inflateReset OF((z_streamp strm));
 598/*
 599     This function is equivalent to inflateEnd followed by inflateInit,
 600   but does not free and reallocate all the internal decompression state.
 601   The stream will keep attributes that may have been set by inflateInit2.
 602
 603      inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
 604   stream state was inconsistent (such as zalloc or state being NULL).
 605*/
 606
 607extern int ZEXPORT zlib_inflateIncomp OF((z_stream *strm));
 608/*
 609     This function adds the data at next_in (avail_in bytes) to the output
 610   history without performing any output.  There must be no pending output,
 611   and the decompressor must be expecting to see the start of a block.
 612   Calling this function is equivalent to decompressing a stored block
 613   containing the data at next_in (except that the data is not output).
 614*/
 615
 616                        /* various hacks, don't look :) */
 617
 618/* deflateInit and inflateInit are macros to allow checking the zlib version
 619 * and the compiler's view of z_stream:
 620 */
 621ZEXTERN int ZEXPORT zlib_deflateInit_ OF((z_streamp strm, int level,
 622                                     const char *version, int stream_size));
 623ZEXTERN int ZEXPORT zlib_inflateInit_ OF((z_streamp strm,
 624                                     const char *version, int stream_size));
 625ZEXTERN int ZEXPORT zlib_deflateInit2_ OF((z_streamp strm, int  level, int  method,
 626                                      int windowBits, int memLevel,
 627                                      int strategy, const char *version,
 628                                      int stream_size));
 629ZEXTERN int ZEXPORT zlib_inflateInit2_ OF((z_streamp strm, int  windowBits,
 630                                      const char *version, int stream_size));
 631#define zlib_deflateInit(strm, level) \
 632        zlib_deflateInit_((strm), (level), ZLIB_VERSION, sizeof(z_stream))
 633#define zlib_inflateInit(strm) \
 634        zlib_inflateInit_((strm), ZLIB_VERSION, sizeof(z_stream))
 635#define zlib_deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
 636        zlib_deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
 637                      (strategy), ZLIB_VERSION, sizeof(z_stream))
 638#define zlib_inflateInit2(strm, windowBits) \
 639        zlib_inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream))
 640
 641
 642#if !defined(_Z_UTIL_H) && !defined(NO_DUMMY_DECL)
 643    struct internal_state {int dummy;}; /* hack for buggy compilers */
 644#endif
 645
 646ZEXTERN const char   * ZEXPORT zlib_zError           OF((int err));
 647ZEXTERN int            ZEXPORT zlib_inflateSyncPoint OF((z_streamp z));
 648ZEXTERN const uLongf * ZEXPORT zlib_get_crc_table    OF((void));
 649
 650#ifdef __cplusplus
 651}
 652#endif
 653
 654#endif /* _ZLIB_H */
 655
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