source: trunk/third/zlib/zlib.h @ 15211

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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 "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    alloc_func zalloc;  /* used to allocate the internal state */
81    free_func  zfree;   /* used to free the internal state */
82    voidpf     opaque;  /* private data object passed to zalloc and zfree */
83
84    int     data_type;  /* best guess about the data type: ascii or binary */
85    uLong   adler;      /* adler32 value of the uncompressed data */
86    uLong   reserved;   /* reserved for future use */
87} z_stream;
88
89typedef z_stream FAR *z_streamp;
90
91/*
92   The application must update next_in and avail_in when avail_in has
93   dropped to zero. It must update next_out and avail_out when avail_out
94   has dropped to zero. The application must initialize zalloc, zfree and
95   opaque before calling the init function. All other fields are set by the
96   compression library and must not be updated by the application.
97
98   The opaque value provided by the application will be passed as the first
99   parameter for calls of zalloc and zfree. This can be useful for custom
100   memory management. The compression library attaches no meaning to the
101   opaque value.
102
103   zalloc must return Z_NULL if there is not enough memory for the object.
104   If zlib is used in a multi-threaded application, zalloc and zfree must be
105   thread safe.
106
107   On 16-bit systems, the functions zalloc and zfree must be able to allocate
108   exactly 65536 bytes, but will not be required to allocate more than this
109   if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS,
110   pointers returned by zalloc for objects of exactly 65536 bytes *must*
111   have their offset normalized to zero. The default allocation function
112   provided by this library ensures this (see zutil.c). To reduce memory
113   requirements and avoid any allocation of 64K objects, at the expense of
114   compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h).
115
116   The fields total_in and total_out can be used for statistics or
117   progress reports. After compression, total_in holds the total size of
118   the uncompressed data and may be saved for use in the decompressor
119   (particularly if the decompressor wants to decompress everything in
120   a single step).
121*/
122
123                        /* constants */
124
125#define Z_NO_FLUSH      0
126#define Z_PARTIAL_FLUSH 1 /* will be removed, use Z_SYNC_FLUSH instead */
127#define Z_SYNC_FLUSH    2
128#define Z_FULL_FLUSH    3
129#define Z_FINISH        4
130/* Allowed flush values; see deflate() below for details */
131
132#define Z_OK            0
133#define Z_STREAM_END    1
134#define Z_NEED_DICT     2
135#define Z_ERRNO        (-1)
136#define Z_STREAM_ERROR (-2)
137#define Z_DATA_ERROR   (-3)
138#define Z_MEM_ERROR    (-4)
139#define Z_BUF_ERROR    (-5)
140#define Z_VERSION_ERROR (-6)
141/* Return codes for the compression/decompression functions. Negative
142 * values are errors, positive values are used for special but normal events.
143 */
144
145#define Z_NO_COMPRESSION         0
146#define Z_BEST_SPEED             1
147#define Z_BEST_COMPRESSION       9
148#define Z_DEFAULT_COMPRESSION  (-1)
149/* compression levels */
150
151#define Z_FILTERED            1
152#define Z_HUFFMAN_ONLY        2
153#define Z_DEFAULT_STRATEGY    0
154/* compression strategy; see deflateInit2() below for details */
155
156#define Z_BINARY   0
157#define Z_ASCII    1
158#define Z_UNKNOWN  2
159/* Possible values of the data_type field */
160
161#define Z_DEFLATED   8
162/* The deflate compression method (the only one supported in this version) */
163
164#define Z_NULL  0  /* for initializing zalloc, zfree, opaque */
165
166#define zlib_version zlibVersion()
167/* for compatibility with versions < 1.0.2 */
168
169                        /* basic functions */
170
171ZEXTERN const char * ZEXPORT zlibVersion OF((void));
172/* The application can compare zlibVersion and ZLIB_VERSION for consistency.
173   If the first character differs, the library code actually used is
174   not compatible with the zlib.h header file used by the application.
175   This check is automatically made by deflateInit and inflateInit.
176 */
177
178/*
179ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level));
180
181     Initializes the internal stream state for compression. The fields
182   zalloc, zfree and opaque must be initialized before by the caller.
183   If zalloc and zfree are set to Z_NULL, deflateInit updates them to
184   use default allocation functions.
185
186     The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
187   1 gives best speed, 9 gives best compression, 0 gives no compression at
188   all (the input data is simply copied a block at a time).
189   Z_DEFAULT_COMPRESSION requests a default compromise between speed and
190   compression (currently equivalent to level 6).
191
192     deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not
193   enough memory, Z_STREAM_ERROR if level is not a valid compression level,
194   Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
195   with the version assumed by the caller (ZLIB_VERSION).
196   msg is set to null if there is no error message.  deflateInit does not
197   perform any compression: this will be done by deflate().
198*/
199
200
201ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush));
202/*
203    deflate compresses as much data as possible, and stops when the input
204  buffer becomes empty or the output buffer becomes full. It may introduce some
205  output latency (reading input without producing any output) except when
206  forced to flush.
207
208    The detailed semantics are as follows. deflate performs one or both of the
209  following actions:
210
211  - Compress more input starting at next_in and update next_in and avail_in
212    accordingly. If not all input can be processed (because there is not
213    enough room in the output buffer), next_in and avail_in are updated and
214    processing will resume at this point for the next call of deflate().
215
216  - Provide more output starting at next_out and update next_out and avail_out
217    accordingly. This action is forced if the parameter flush is non zero.
218    Forcing flush frequently degrades the compression ratio, so this parameter
219    should be set only when necessary (in interactive applications).
220    Some output may be provided even if flush is not set.
221
222  Before the call of deflate(), the application should ensure that at least
223  one of the actions is possible, by providing more input and/or consuming
224  more output, and updating avail_in or avail_out accordingly; avail_out
225  should never be zero before the call. The application can consume the
226  compressed output when it wants, for example when the output buffer is full
227  (avail_out == 0), or after each call of deflate(). If deflate returns Z_OK
228  and with zero avail_out, it must be called again after making room in the
229  output buffer because there might be more output pending.
230
231    If the parameter flush is set to Z_SYNC_FLUSH, all pending output is
232  flushed to the output buffer and the output is aligned on a byte boundary, so
233  that the decompressor can get all input data available so far. (In particular
234  avail_in is zero after the call if enough output space has been provided
235  before the call.)  Flushing may degrade compression for some compression
236  algorithms and so it should be used only when necessary.
237
238    If flush is set to Z_FULL_FLUSH, all output is flushed as with
239  Z_SYNC_FLUSH, and the compression state is reset so that decompression can
240  restart from this point if previous compressed data has been damaged or if
241  random access is desired. Using Z_FULL_FLUSH too often can seriously degrade
242  the compression.
243
244    If deflate returns with avail_out == 0, this function must be called again
245  with the same value of the flush parameter and more output space (updated
246  avail_out), until the flush is complete (deflate returns with non-zero
247  avail_out).
248
249    If the parameter flush is set to Z_FINISH, pending input is processed,
250  pending output is flushed and deflate returns with Z_STREAM_END if there
251  was enough output space; if deflate returns with Z_OK, this function must be
252  called again with Z_FINISH and more output space (updated avail_out) but no
253  more input data, until it returns with Z_STREAM_END or an error. After
254  deflate has returned Z_STREAM_END, the only possible operations on the
255  stream are deflateReset or deflateEnd.
256 
257    Z_FINISH can be used immediately after deflateInit if all the compression
258  is to be done in a single step. In this case, avail_out must be at least
259  0.1% larger than avail_in plus 12 bytes.  If deflate does not return
260  Z_STREAM_END, then it must be called again as described above.
261
262    deflate() sets strm->adler to the adler32 checksum of all input read
263  so far (that is, total_in bytes).
264
265    deflate() may update data_type if it can make a good guess about
266  the input data type (Z_ASCII or Z_BINARY). In doubt, the data is considered
267  binary. This field is only for information purposes and does not affect
268  the compression algorithm in any manner.
269
270    deflate() returns Z_OK if some progress has been made (more input
271  processed or more output produced), Z_STREAM_END if all input has been
272  consumed and all output has been produced (only when flush is set to
273  Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
274  if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible
275  (for example avail_in or avail_out was zero).
276*/
277
278
279ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm));
280/*
281     All dynamically allocated data structures for this stream are freed.
282   This function discards any unprocessed input and does not flush any
283   pending output.
284
285     deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
286   stream state was inconsistent, Z_DATA_ERROR if the stream was freed
287   prematurely (some input or output was discarded). In the error case,
288   msg may be set but then points to a static string (which must not be
289   deallocated).
290*/
291
292
293/*
294ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm));
295
296     Initializes the internal stream state for decompression. The fields
297   next_in, avail_in, zalloc, zfree and opaque must be initialized before by
298   the caller. If next_in is not Z_NULL and avail_in is large enough (the exact
299   value depends on the compression method), inflateInit determines the
300   compression method from the zlib header and allocates all data structures
301   accordingly; otherwise the allocation will be deferred to the first call of
302   inflate.  If zalloc and zfree are set to Z_NULL, inflateInit updates them to
303   use default allocation functions.
304
305     inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
306   memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
307   version assumed by the caller.  msg is set to null if there is no error
308   message. inflateInit does not perform any decompression apart from reading
309   the zlib header if present: this will be done by inflate().  (So next_in and
310   avail_in may be modified, but next_out and avail_out are unchanged.)
311*/
312
313
314ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush));
315/*
316    inflate decompresses as much data as possible, and stops when the input
317  buffer becomes empty or the output buffer becomes full. It may some
318  introduce some output latency (reading input without producing any output)
319  except when forced to flush.
320
321  The detailed semantics are as follows. inflate performs one or both of the
322  following actions:
323
324  - Decompress more input starting at next_in and update next_in and avail_in
325    accordingly. If not all input can be processed (because there is not
326    enough room in the output buffer), next_in is updated and processing
327    will resume at this point for the next call of inflate().
328
329  - Provide more output starting at next_out and update next_out and avail_out
330    accordingly.  inflate() provides as much output as possible, until there
331    is no more input data or no more space in the output buffer (see below
332    about the flush parameter).
333
334  Before the call of inflate(), the application should ensure that at least
335  one of the actions is possible, by providing more input and/or consuming
336  more output, and updating the next_* and avail_* values accordingly.
337  The application can consume the uncompressed output when it wants, for
338  example when the output buffer is full (avail_out == 0), or after each
339  call of inflate(). If inflate returns Z_OK and with zero avail_out, it
340  must be called again after making room in the output buffer because there
341  might be more output pending.
342
343    If the parameter flush is set to Z_SYNC_FLUSH, inflate flushes as much
344  output as possible to the output buffer. The flushing behavior of inflate is
345  not specified for values of the flush parameter other than Z_SYNC_FLUSH
346  and Z_FINISH, but the current implementation actually flushes as much output
347  as possible anyway.
348
349    inflate() should normally be called until it returns Z_STREAM_END or an
350  error. However if all decompression is to be performed in a single step
351  (a single call of inflate), the parameter flush should be set to
352  Z_FINISH. In this case all pending input is processed and all pending
353  output is flushed; avail_out must be large enough to hold all the
354  uncompressed data. (The size of the uncompressed data may have been saved
355  by the compressor for this purpose.) The next operation on this stream must
356  be inflateEnd to deallocate the decompression state. The use of Z_FINISH
357  is never required, but can be used to inform inflate that a faster routine
358  may be used for the single inflate() call.
359
360     If a preset dictionary is needed at this point (see inflateSetDictionary
361  below), inflate sets strm-adler to the adler32 checksum of the
362  dictionary chosen by the compressor and returns Z_NEED_DICT; otherwise
363  it sets strm->adler to the adler32 checksum of all output produced
364  so far (that is, total_out bytes) and returns Z_OK, Z_STREAM_END or
365  an error code as described below. At the end of the stream, inflate()
366  checks that its computed adler32 checksum is equal to that saved by the
367  compressor and returns Z_STREAM_END only if the checksum is correct.
368
369    inflate() returns Z_OK if some progress has been made (more input processed
370  or more output produced), Z_STREAM_END if the end of the compressed data has
371  been reached and all uncompressed output has been produced, Z_NEED_DICT if a
372  preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
373  corrupted (input stream not conforming to the zlib format or incorrect
374  adler32 checksum), Z_STREAM_ERROR if the stream structure was inconsistent
375  (for example if next_in or next_out was NULL), Z_MEM_ERROR if there was not
376  enough memory, Z_BUF_ERROR if no progress is possible or if there was not
377  enough room in the output buffer when Z_FINISH is used. In the Z_DATA_ERROR
378  case, the application may then call inflateSync to look for a good
379  compression block.
380*/
381
382
383ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm));
384/*
385     All dynamically allocated data structures for this stream are freed.
386   This function discards any unprocessed input and does not flush any
387   pending output.
388
389     inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state
390   was inconsistent. In the error case, msg may be set but then points to a
391   static string (which must not be deallocated).
392*/
393
394                        /* Advanced functions */
395
396/*
397    The following functions are needed only in some special applications.
398*/
399
400/*   
401ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm,
402                                     int  level,
403                                     int  method,
404                                     int  windowBits,
405                                     int  memLevel,
406                                     int  strategy));
407
408     This is another version of deflateInit with more compression options. The
409   fields next_in, zalloc, zfree and opaque must be initialized before by
410   the caller.
411
412     The method parameter is the compression method. It must be Z_DEFLATED in
413   this version of the library.
414
415     The windowBits parameter is the base two logarithm of the window size
416   (the size of the history buffer).  It should be in the range 8..15 for this
417   version of the library. Larger values of this parameter result in better
418   compression at the expense of memory usage. The default value is 15 if
419   deflateInit is used instead.
420
421     The memLevel parameter specifies how much memory should be allocated
422   for the internal compression state. memLevel=1 uses minimum memory but
423   is slow and reduces compression ratio; memLevel=9 uses maximum memory
424   for optimal speed. The default value is 8. See zconf.h for total memory
425   usage as a function of windowBits and memLevel.
426
427     The strategy parameter is used to tune the compression algorithm. Use the
428   value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
429   filter (or predictor), or Z_HUFFMAN_ONLY to force Huffman encoding only (no
430   string match).  Filtered data consists mostly of small values with a
431   somewhat random distribution. In this case, the compression algorithm is
432   tuned to compress them better. The effect of Z_FILTERED is to force more
433   Huffman coding and less string matching; it is somewhat intermediate
434   between Z_DEFAULT and Z_HUFFMAN_ONLY. The strategy parameter only affects
435   the compression ratio but not the correctness of the compressed output even
436   if it is not set appropriately.
437
438      deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
439   memory, Z_STREAM_ERROR if a parameter is invalid (such as an invalid
440   method). msg is set to null if there is no error message.  deflateInit2 does
441   not perform any compression: this will be done by deflate().
442*/
443                           
444ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm,
445                                             const Bytef *dictionary,
446                                             uInt  dictLength));
447/*
448     Initializes the compression dictionary from the given byte sequence
449   without producing any compressed output. This function must be called
450   immediately after deflateInit, deflateInit2 or deflateReset, before any
451   call of deflate. The compressor and decompressor must use exactly the same
452   dictionary (see inflateSetDictionary).
453
454     The dictionary should consist of strings (byte sequences) that are likely
455   to be encountered later in the data to be compressed, with the most commonly
456   used strings preferably put towards the end of the dictionary. Using a
457   dictionary is most useful when the data to be compressed is short and can be
458   predicted with good accuracy; the data can then be compressed better than
459   with the default empty dictionary.
460
461     Depending on the size of the compression data structures selected by
462   deflateInit or deflateInit2, a part of the dictionary may in effect be
463   discarded, for example if the dictionary is larger than the window size in
464   deflate or deflate2. Thus the strings most likely to be useful should be
465   put at the end of the dictionary, not at the front.
466
467     Upon return of this function, strm->adler is set to the Adler32 value
468   of the dictionary; the decompressor may later use this value to determine
469   which dictionary has been used by the compressor. (The Adler32 value
470   applies to the whole dictionary even if only a subset of the dictionary is
471   actually used by the compressor.)
472
473     deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
474   parameter is invalid (such as NULL dictionary) or the stream state is
475   inconsistent (for example if deflate has already been called for this stream
476   or if the compression method is bsort). deflateSetDictionary does not
477   perform any compression: this will be done by deflate().
478*/
479
480ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest,
481                                    z_streamp source));
482/*
483     Sets the destination stream as a complete copy of the source stream.
484
485     This function can be useful when several compression strategies will be
486   tried, for example when there are several ways of pre-processing the input
487   data with a filter. The streams that will be discarded should then be freed
488   by calling deflateEnd.  Note that deflateCopy duplicates the internal
489   compression state which can be quite large, so this strategy is slow and
490   can consume lots of memory.
491
492     deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
493   enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
494   (such as zalloc being NULL). msg is left unchanged in both source and
495   destination.
496*/
497
498ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm));
499/*
500     This function is equivalent to deflateEnd followed by deflateInit,
501   but does not free and reallocate all the internal compression state.
502   The stream will keep the same compression level and any other attributes
503   that may have been set by deflateInit2.
504
505      deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
506   stream state was inconsistent (such as zalloc or state being NULL).
507*/
508
509ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm,
510                                      int level,
511                                      int strategy));
512/*
513     Dynamically update the compression level and compression strategy.  The
514   interpretation of level and strategy is as in deflateInit2.  This can be
515   used to switch between compression and straight copy of the input data, or
516   to switch to a different kind of input data requiring a different
517   strategy. If the compression level is changed, the input available so far
518   is compressed with the old level (and may be flushed); the new level will
519   take effect only at the next call of deflate().
520
521     Before the call of deflateParams, the stream state must be set as for
522   a call of deflate(), since the currently available input may have to
523   be compressed and flushed. In particular, strm->avail_out must be non-zero.
524
525     deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source
526   stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR
527   if strm->avail_out was zero.
528*/
529
530/*   
531ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm,
532                                     int  windowBits));
533
534     This is another version of inflateInit with an extra parameter. The
535   fields next_in, avail_in, zalloc, zfree and opaque must be initialized
536   before by the caller.
537
538     The windowBits parameter is the base two logarithm of the maximum window
539   size (the size of the history buffer).  It should be in the range 8..15 for
540   this version of the library. The default value is 15 if inflateInit is used
541   instead. If a compressed stream with a larger window size is given as
542   input, inflate() will return with the error code Z_DATA_ERROR instead of
543   trying to allocate a larger window.
544
545      inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
546   memory, Z_STREAM_ERROR if a parameter is invalid (such as a negative
547   memLevel). msg is set to null if there is no error message.  inflateInit2
548   does not perform any decompression apart from reading the zlib header if
549   present: this will be done by inflate(). (So next_in and avail_in may be
550   modified, but next_out and avail_out are unchanged.)
551*/
552
553ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm,
554                                             const Bytef *dictionary,
555                                             uInt  dictLength));
556/*
557     Initializes the decompression dictionary from the given uncompressed byte
558   sequence. This function must be called immediately after a call of inflate
559   if this call returned Z_NEED_DICT. The dictionary chosen by the compressor
560   can be determined from the Adler32 value returned by this call of
561   inflate. The compressor and decompressor must use exactly the same
562   dictionary (see deflateSetDictionary).
563
564     inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
565   parameter is invalid (such as NULL dictionary) or the stream state is
566   inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
567   expected one (incorrect Adler32 value). inflateSetDictionary does not
568   perform any decompression: this will be done by subsequent calls of
569   inflate().
570*/
571
572ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm));
573/*
574    Skips invalid compressed data until a full flush point (see above the
575  description of deflate with Z_FULL_FLUSH) can be found, or until all
576  available input is skipped. No output is provided.
577
578    inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR
579  if no more input was provided, Z_DATA_ERROR if no flush point has been found,
580  or Z_STREAM_ERROR if the stream structure was inconsistent. In the success
581  case, the application may save the current current value of total_in which
582  indicates where valid compressed data was found. In the error case, the
583  application may repeatedly call inflateSync, providing more input each time,
584  until success or end of the input data.
585*/
586
587ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm));
588/*
589     This function is equivalent to inflateEnd followed by inflateInit,
590   but does not free and reallocate all the internal decompression state.
591   The stream will keep attributes that may have been set by inflateInit2.
592
593      inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
594   stream state was inconsistent (such as zalloc or state being NULL).
595*/
596
597
598                        /* utility functions */
599
600/*
601     The following utility functions are implemented on top of the
602   basic stream-oriented functions. To simplify the interface, some
603   default options are assumed (compression level and memory usage,
604   standard memory allocation functions). The source code of these
605   utility functions can easily be modified if you need special options.
606*/
607
608ZEXTERN int ZEXPORT compress OF((Bytef *dest,   uLongf *destLen,
609                                 const Bytef *source, uLong sourceLen));
610/*
611     Compresses the source buffer into the destination buffer.  sourceLen is
612   the byte length of the source buffer. Upon entry, destLen is the total
613   size of the destination buffer, which must be at least 0.1% larger than
614   sourceLen plus 12 bytes. Upon exit, destLen is the actual size of the
615   compressed buffer.
616     This function can be used to compress a whole file at once if the
617   input file is mmap'ed.
618     compress returns Z_OK if success, Z_MEM_ERROR if there was not
619   enough memory, Z_BUF_ERROR if there was not enough room in the output
620   buffer.
621*/
622
623ZEXTERN int ZEXPORT compress2 OF((Bytef *dest,   uLongf *destLen,
624                                  const Bytef *source, uLong sourceLen,
625                                  int level));
626/*
627     Compresses the source buffer into the destination buffer. The level
628   parameter has the same meaning as in deflateInit.  sourceLen is the byte
629   length of the source buffer. Upon entry, destLen is the total size of the
630   destination buffer, which must be at least 0.1% larger than sourceLen plus
631   12 bytes. Upon exit, destLen is the actual size of the compressed buffer.
632
633     compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
634   memory, Z_BUF_ERROR if there was not enough room in the output buffer,
635   Z_STREAM_ERROR if the level parameter is invalid.
636*/
637
638ZEXTERN int ZEXPORT uncompress OF((Bytef *dest,   uLongf *destLen,
639                                   const Bytef *source, uLong sourceLen));
640/*
641     Decompresses the source buffer into the destination buffer.  sourceLen is
642   the byte length of the source buffer. Upon entry, destLen is the total
643   size of the destination buffer, which must be large enough to hold the
644   entire uncompressed data. (The size of the uncompressed data must have
645   been saved previously by the compressor and transmitted to the decompressor
646   by some mechanism outside the scope of this compression library.)
647   Upon exit, destLen is the actual size of the compressed buffer.
648     This function can be used to decompress a whole file at once if the
649   input file is mmap'ed.
650
651     uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
652   enough memory, Z_BUF_ERROR if there was not enough room in the output
653   buffer, or Z_DATA_ERROR if the input data was corrupted.
654*/
655
656
657typedef voidp gzFile;
658
659ZEXTERN gzFile ZEXPORT gzopen  OF((const char *path, const char *mode));
660/*
661     Opens a gzip (.gz) file for reading or writing. The mode parameter
662   is as in fopen ("rb" or "wb") but can also include a compression level
663   ("wb9") or a strategy: 'f' for filtered data as in "wb6f", 'h' for
664   Huffman only compression as in "wb1h". (See the description
665   of deflateInit2 for more information about the strategy parameter.)
666
667     gzopen can be used to read a file which is not in gzip format; in this
668   case gzread will directly read from the file without decompression.
669
670     gzopen returns NULL if the file could not be opened or if there was
671   insufficient memory to allocate the (de)compression state; errno
672   can be checked to distinguish the two cases (if errno is zero, the
673   zlib error is Z_MEM_ERROR).  */
674
675ZEXTERN gzFile ZEXPORT gzdopen  OF((int fd, const char *mode));
676/*
677     gzdopen() associates a gzFile with the file descriptor fd.  File
678   descriptors are obtained from calls like open, dup, creat, pipe or
679   fileno (in the file has been previously opened with fopen).
680   The mode parameter is as in gzopen.
681     The next call of gzclose on the returned gzFile will also close the
682   file descriptor fd, just like fclose(fdopen(fd), mode) closes the file
683   descriptor fd. If you want to keep fd open, use gzdopen(dup(fd), mode).
684     gzdopen returns NULL if there was insufficient memory to allocate
685   the (de)compression state.
686*/
687
688ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy));
689/*
690     Dynamically update the compression level or strategy. See the description
691   of deflateInit2 for the meaning of these parameters.
692     gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not
693   opened for writing.
694*/
695
696ZEXTERN int ZEXPORT    gzread  OF((gzFile file, voidp buf, unsigned len));
697/*
698     Reads the given number of uncompressed bytes from the compressed file.
699   If the input file was not in gzip format, gzread copies the given number
700   of bytes into the buffer.
701     gzread returns the number of uncompressed bytes actually read (0 for
702   end of file, -1 for error). */
703
704ZEXTERN int ZEXPORT    gzwrite OF((gzFile file,
705                                   const voidp buf, unsigned len));
706/*
707     Writes the given number of uncompressed bytes into the compressed file.
708   gzwrite returns the number of uncompressed bytes actually written
709   (0 in case of error).
710*/
711
712ZEXTERN int ZEXPORTVA   gzprintf OF((gzFile file, const char *format, ...));
713/*
714     Converts, formats, and writes the args to the compressed file under
715   control of the format string, as in fprintf. gzprintf returns the number of
716   uncompressed bytes actually written (0 in case of error).
717*/
718
719ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s));
720/*
721      Writes the given null-terminated string to the compressed file, excluding
722   the terminating null character.
723      gzputs returns the number of characters written, or -1 in case of error.
724*/
725
726ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len));
727/*
728      Reads bytes from the compressed file until len-1 characters are read, or
729   a newline character is read and transferred to buf, or an end-of-file
730   condition is encountered.  The string is then terminated with a null
731   character.
732      gzgets returns buf, or Z_NULL in case of error.
733*/
734
735ZEXTERN int ZEXPORT    gzputc OF((gzFile file, int c));
736/*
737      Writes c, converted to an unsigned char, into the compressed file.
738   gzputc returns the value that was written, or -1 in case of error.
739*/
740
741ZEXTERN int ZEXPORT    gzgetc OF((gzFile file));
742/*
743      Reads one byte from the compressed file. gzgetc returns this byte
744   or -1 in case of end of file or error.
745*/
746
747ZEXTERN int ZEXPORT    gzflush OF((gzFile file, int flush));
748/*
749     Flushes all pending output into the compressed file. The parameter
750   flush is as in the deflate() function. The return value is the zlib
751   error number (see function gzerror below). gzflush returns Z_OK if
752   the flush parameter is Z_FINISH and all output could be flushed.
753     gzflush should be called only when strictly necessary because it can
754   degrade compression.
755*/
756
757ZEXTERN z_off_t ZEXPORT    gzseek OF((gzFile file,
758                                      z_off_t offset, int whence));
759/*
760      Sets the starting position for the next gzread or gzwrite on the
761   given compressed file. The offset represents a number of bytes in the
762   uncompressed data stream. The whence parameter is defined as in lseek(2);
763   the value SEEK_END is not supported.
764     If the file is opened for reading, this function is emulated but can be
765   extremely slow. If the file is opened for writing, only forward seeks are
766   supported; gzseek then compresses a sequence of zeroes up to the new
767   starting position.
768
769      gzseek returns the resulting offset location as measured in bytes from
770   the beginning of the uncompressed stream, or -1 in case of error, in
771   particular if the file is opened for writing and the new starting position
772   would be before the current position.
773*/
774
775ZEXTERN int ZEXPORT    gzrewind OF((gzFile file));
776/*
777     Rewinds the given file. This function is supported only for reading.
778
779   gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET)
780*/
781
782ZEXTERN z_off_t ZEXPORT    gztell OF((gzFile file));
783/*
784     Returns the starting position for the next gzread or gzwrite on the
785   given compressed file. This position represents a number of bytes in the
786   uncompressed data stream.
787
788   gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)
789*/
790
791ZEXTERN int ZEXPORT gzeof OF((gzFile file));
792/*
793     Returns 1 when EOF has previously been detected reading the given
794   input stream, otherwise zero.
795*/
796
797ZEXTERN int ZEXPORT    gzclose OF((gzFile file));
798/*
799     Flushes all pending output if necessary, closes the compressed file
800   and deallocates all the (de)compression state. The return value is the zlib
801   error number (see function gzerror below).
802*/
803
804ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum));
805/*
806     Returns the error message for the last error which occurred on the
807   given compressed file. errnum is set to zlib error number. If an
808   error occurred in the file system and not in the compression library,
809   errnum is set to Z_ERRNO and the application may consult errno
810   to get the exact error code.
811*/
812
813                        /* checksum functions */
814
815/*
816     These functions are not related to compression but are exported
817   anyway because they might be useful in applications using the
818   compression library.
819*/
820
821ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len));
822
823/*
824     Update a running Adler-32 checksum with the bytes buf[0..len-1] and
825   return the updated checksum. If buf is NULL, this function returns
826   the required initial value for the checksum.
827   An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
828   much faster. Usage example:
829
830     uLong adler = adler32(0L, Z_NULL, 0);
831
832     while (read_buffer(buffer, length) != EOF) {
833       adler = adler32(adler, buffer, length);
834     }
835     if (adler != original_adler) error();
836*/
837
838ZEXTERN uLong ZEXPORT crc32   OF((uLong crc, const Bytef *buf, uInt len));
839/*
840     Update a running crc with the bytes buf[0..len-1] and return the updated
841   crc. If buf is NULL, this function returns the required initial value
842   for the crc. Pre- and post-conditioning (one's complement) is performed
843   within this function so it shouldn't be done by the application.
844   Usage example:
845
846     uLong crc = crc32(0L, Z_NULL, 0);
847
848     while (read_buffer(buffer, length) != EOF) {
849       crc = crc32(crc, buffer, length);
850     }
851     if (crc != original_crc) error();
852*/
853
854
855                        /* various hacks, don't look :) */
856
857/* deflateInit and inflateInit are macros to allow checking the zlib version
858 * and the compiler's view of z_stream:
859 */
860ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level,
861                                     const char *version, int stream_size));
862ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm,
863                                     const char *version, int stream_size));
864ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int  level, int  method,
865                                      int windowBits, int memLevel,
866                                      int strategy, const char *version,
867                                      int stream_size));
868ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int  windowBits,
869                                      const char *version, int stream_size));
870#define deflateInit(strm, level) \
871        deflateInit_((strm), (level),       ZLIB_VERSION, sizeof(z_stream))
872#define inflateInit(strm) \
873        inflateInit_((strm),                ZLIB_VERSION, sizeof(z_stream))
874#define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
875        deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
876                      (strategy),           ZLIB_VERSION, sizeof(z_stream))
877#define inflateInit2(strm, windowBits) \
878        inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream))
879
880
881#if !defined(_Z_UTIL_H) && !defined(NO_DUMMY_DECL)
882    struct internal_state {int dummy;}; /* hack for buggy compilers */
883#endif
884
885ZEXTERN const char   * ZEXPORT zError           OF((int err));
886ZEXTERN int            ZEXPORT inflateSyncPoint OF((z_streamp z));
887ZEXTERN const uLongf * ZEXPORT get_crc_table    OF((void));
888
889#ifdef __cplusplus
890}
891#endif
892
893#endif /* _ZLIB_H */
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