source: trunk/source/visualization/externals/zlib/include/zlib.h @ 850

Last change on this file since 850 was 562, checked in by garnier, 17 years ago

r565@mac-90108: laurentgarnier | 2007-08-14 14:18:03 +0200
mise a jour suite au plantage de svk (cheksum error) suite au crash du DD en juin

File size: 56.4 KB
Line 
1/* zlib.h -- interface of the 'zlib' general purpose compression library
2  version 1.2.2, October 3rd, 2004
3
4  Copyright (C) 1995-2004 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 http://www.ietf.org/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 "1.2.2"
41#define ZLIB_VERNUM 0x1220
42
43/*
44     The 'zlib' compression library provides in-memory compression and
45  decompression functions, including integrity checks of the uncompressed
46  data.  This version of the library supports only one compression method
47  (deflation) but other algorithms will be added later and will have the same
48  stream interface.
49
50     Compression can be done in a single step if the buffers are large
51  enough (for example if an input file is mmap'ed), or can be done by
52  repeated calls of the compression function.  In the latter case, the
53  application must provide more input and/or consume the output
54  (providing more output space) before each call.
55
56     The compressed data format used by default by the in-memory functions is
57  the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped
58  around a deflate stream, which is itself documented in RFC 1951.
59
60     The library also supports reading and writing files in gzip (.gz) format
61  with an interface similar to that of stdio using the functions that start
62  with "gz".  The gzip format is different from the zlib format.  gzip is a
63  gzip wrapper, documented in RFC 1952, wrapped around a deflate stream.
64
65     This library can optionally read and write gzip streams in memory as well.
66
67     The zlib format was designed to be compact and fast for use in memory
68  and on communications channels.  The gzip format was designed for single-
69  file compression on file systems, has a larger header than zlib to maintain
70  directory information, and uses a different, slower check method than zlib.
71
72     The library does not install any signal handler. The decoder checks
73  the consistency of the compressed data, so the library should never
74  crash even in case of corrupted input.
75*/
76
77typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size));
78typedef void   (*free_func)  OF((voidpf opaque, voidpf address));
79
80struct internal_state;
81
82typedef struct z_stream_s {
83    Bytef    *next_in;  /* next input byte */
84    uInt     avail_in;  /* number of bytes available at next_in */
85    uLong    total_in;  /* total nb of input bytes read so far */
86
87    Bytef    *next_out; /* next output byte should be put there */
88    uInt     avail_out; /* remaining free space at next_out */
89    uLong    total_out; /* total nb of bytes output so far */
90
91    char     *msg;      /* last error message, NULL if no error */
92    struct internal_state FAR *state; /* not visible by applications */
93
94    alloc_func zalloc;  /* used to allocate the internal state */
95    free_func  zfree;   /* used to free the internal state */
96    voidpf     opaque;  /* private data object passed to zalloc and zfree */
97
98    int     data_type;  /* best guess about the data type: ascii or binary */
99    uLong   adler;      /* adler32 value of the uncompressed data */
100    uLong   reserved;   /* reserved for future use */
101} z_stream;
102
103typedef z_stream FAR *z_streamp;
104
105/*
106   The application must update next_in and avail_in when avail_in has
107   dropped to zero. It must update next_out and avail_out when avail_out
108   has dropped to zero. The application must initialize zalloc, zfree and
109   opaque before calling the init function. All other fields are set by the
110   compression library and must not be updated by the application.
111
112   The opaque value provided by the application will be passed as the first
113   parameter for calls of zalloc and zfree. This can be useful for custom
114   memory management. The compression library attaches no meaning to the
115   opaque value.
116
117   zalloc must return Z_NULL if there is not enough memory for the object.
118   If zlib is used in a multi-threaded application, zalloc and zfree must be
119   thread safe.
120
121   On 16-bit systems, the functions zalloc and zfree must be able to allocate
122   exactly 65536 bytes, but will not be required to allocate more than this
123   if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS,
124   pointers returned by zalloc for objects of exactly 65536 bytes *must*
125   have their offset normalized to zero. The default allocation function
126   provided by this library ensures this (see zutil.c). To reduce memory
127   requirements and avoid any allocation of 64K objects, at the expense of
128   compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h).
129
130   The fields total_in and total_out can be used for statistics or
131   progress reports. After compression, total_in holds the total size of
132   the uncompressed data and may be saved for use in the decompressor
133   (particularly if the decompressor wants to decompress everything in
134   a single step).
135*/
136
137                        /* constants */
138
139#define Z_NO_FLUSH      0
140#define Z_PARTIAL_FLUSH 1 /* will be removed, use Z_SYNC_FLUSH instead */
141#define Z_SYNC_FLUSH    2
142#define Z_FULL_FLUSH    3
143#define Z_FINISH        4
144#define Z_BLOCK         5
145/* Allowed flush values; see deflate() and inflate() below for details */
146
147#define Z_OK            0
148#define Z_STREAM_END    1
149#define Z_NEED_DICT     2
150#define Z_ERRNO        (-1)
151#define Z_STREAM_ERROR (-2)
152#define Z_DATA_ERROR   (-3)
153#define Z_MEM_ERROR    (-4)
154#define Z_BUF_ERROR    (-5)
155#define Z_VERSION_ERROR (-6)
156/* Return codes for the compression/decompression functions. Negative
157 * values are errors, positive values are used for special but normal events.
158 */
159
160#define Z_NO_COMPRESSION         0
161#define Z_BEST_SPEED             1
162#define Z_BEST_COMPRESSION       9
163#define Z_DEFAULT_COMPRESSION  (-1)
164/* compression levels */
165
166#define Z_FILTERED            1
167#define Z_HUFFMAN_ONLY        2
168#define Z_RLE                 3
169#define Z_DEFAULT_STRATEGY    0
170/* compression strategy; see deflateInit2() below for details */
171
172#define Z_BINARY   0
173#define Z_ASCII    1
174#define Z_UNKNOWN  2
175/* Possible values of the data_type field (though see inflate()) */
176
177#define Z_DEFLATED   8
178/* The deflate compression method (the only one supported in this version) */
179
180#define Z_NULL  0  /* for initializing zalloc, zfree, opaque */
181
182#define zlib_version zlibVersion()
183/* for compatibility with versions < 1.0.2 */
184
185                        /* basic functions */
186
187ZEXTERN const char * ZEXPORT zlibVersion OF((void));
188/* The application can compare zlibVersion and ZLIB_VERSION for consistency.
189   If the first character differs, the library code actually used is
190   not compatible with the zlib.h header file used by the application.
191   This check is automatically made by deflateInit and inflateInit.
192 */
193
194/*
195ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level));
196
197     Initializes the internal stream state for compression. The fields
198   zalloc, zfree and opaque must be initialized before by the caller.
199   If zalloc and zfree are set to Z_NULL, deflateInit updates them to
200   use default allocation functions.
201
202     The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
203   1 gives best speed, 9 gives best compression, 0 gives no compression at
204   all (the input data is simply copied a block at a time).
205   Z_DEFAULT_COMPRESSION requests a default compromise between speed and
206   compression (currently equivalent to level 6).
207
208     deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not
209   enough memory, Z_STREAM_ERROR if level is not a valid compression level,
210   Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
211   with the version assumed by the caller (ZLIB_VERSION).
212   msg is set to null if there is no error message.  deflateInit does not
213   perform any compression: this will be done by deflate().
214*/
215
216
217ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush));
218/*
219    deflate compresses as much data as possible, and stops when the input
220  buffer becomes empty or the output buffer becomes full. It may introduce some
221  output latency (reading input without producing any output) except when
222  forced to flush.
223
224    The detailed semantics are as follows. deflate performs one or both of the
225  following actions:
226
227  - Compress more input starting at next_in and update next_in and avail_in
228    accordingly. If not all input can be processed (because there is not
229    enough room in the output buffer), next_in and avail_in are updated and
230    processing will resume at this point for the next call of deflate().
231
232  - Provide more output starting at next_out and update next_out and avail_out
233    accordingly. This action is forced if the parameter flush is non zero.
234    Forcing flush frequently degrades the compression ratio, so this parameter
235    should be set only when necessary (in interactive applications).
236    Some output may be provided even if flush is not set.
237
238  Before the call of deflate(), the application should ensure that at least
239  one of the actions is possible, by providing more input and/or consuming
240  more output, and updating avail_in or avail_out accordingly; avail_out
241  should never be zero before the call. The application can consume the
242  compressed output when it wants, for example when the output buffer is full
243  (avail_out == 0), or after each call of deflate(). If deflate returns Z_OK
244  and with zero avail_out, it must be called again after making room in the
245  output buffer because there might be more output pending.
246
247    If the parameter flush is set to Z_SYNC_FLUSH, all pending output is
248  flushed to the output buffer and the output is aligned on a byte boundary, so
249  that the decompressor can get all input data available so far. (In particular
250  avail_in is zero after the call if enough output space has been provided
251  before the call.)  Flushing may degrade compression for some compression
252  algorithms and so it should be used only when necessary.
253
254    If flush is set to Z_FULL_FLUSH, all output is flushed as with
255  Z_SYNC_FLUSH, and the compression state is reset so that decompression can
256  restart from this point if previous compressed data has been damaged or if
257  random access is desired. Using Z_FULL_FLUSH too often can seriously degrade
258  the compression.
259
260    If deflate returns with avail_out == 0, this function must be called again
261  with the same value of the flush parameter and more output space (updated
262  avail_out), until the flush is complete (deflate returns with non-zero
263  avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that
264  avail_out is greater than six to avoid repeated flush markers due to
265  avail_out == 0 on return.
266
267    If the parameter flush is set to Z_FINISH, pending input is processed,
268  pending output is flushed and deflate returns with Z_STREAM_END if there
269  was enough output space; if deflate returns with Z_OK, this function must be
270  called again with Z_FINISH and more output space (updated avail_out) but no
271  more input data, until it returns with Z_STREAM_END or an error. After
272  deflate has returned Z_STREAM_END, the only possible operations on the
273  stream are deflateReset or deflateEnd.
274
275    Z_FINISH can be used immediately after deflateInit if all the compression
276  is to be done in a single step. In this case, avail_out must be at least
277  the value returned by deflateBound (see below). If deflate does not return
278  Z_STREAM_END, then it must be called again as described above.
279
280    deflate() sets strm->adler to the adler32 checksum of all input read
281  so far (that is, total_in bytes).
282
283    deflate() may update data_type if it can make a good guess about
284  the input data type (Z_ASCII or Z_BINARY). In doubt, the data is considered
285  binary. This field is only for information purposes and does not affect
286  the compression algorithm in any manner.
287
288    deflate() returns Z_OK if some progress has been made (more input
289  processed or more output produced), Z_STREAM_END if all input has been
290  consumed and all output has been produced (only when flush is set to
291  Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
292  if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible
293  (for example avail_in or avail_out was zero). Note that Z_BUF_ERROR is not
294  fatal, and deflate() can be called again with more input and more output
295  space to continue compressing.
296*/
297
298
299ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm));
300/*
301     All dynamically allocated data structures for this stream are freed.
302   This function discards any unprocessed input and does not flush any
303   pending output.
304
305     deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
306   stream state was inconsistent, Z_DATA_ERROR if the stream was freed
307   prematurely (some input or output was discarded). In the error case,
308   msg may be set but then points to a static string (which must not be
309   deallocated).
310*/
311
312
313/*
314ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm));
315
316     Initializes the internal stream state for decompression. The fields
317   next_in, avail_in, zalloc, zfree and opaque must be initialized before by
318   the caller. If next_in is not Z_NULL and avail_in is large enough (the exact
319   value depends on the compression method), inflateInit determines the
320   compression method from the zlib header and allocates all data structures
321   accordingly; otherwise the allocation will be deferred to the first call of
322   inflate.  If zalloc and zfree are set to Z_NULL, inflateInit updates them to
323   use default allocation functions.
324
325     inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
326   memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
327   version assumed by the caller.  msg is set to null if there is no error
328   message. inflateInit does not perform any decompression apart from reading
329   the zlib header if present: this will be done by inflate().  (So next_in and
330   avail_in may be modified, but next_out and avail_out are unchanged.)
331*/
332
333
334ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush));
335/*
336    inflate decompresses as much data as possible, and stops when the input
337  buffer becomes empty or the output buffer becomes full. It may introduce
338  some output latency (reading input without producing any output) except when
339  forced to flush.
340
341  The detailed semantics are as follows. inflate performs one or both of the
342  following actions:
343
344  - Decompress more input starting at next_in and update next_in and avail_in
345    accordingly. If not all input can be processed (because there is not
346    enough room in the output buffer), next_in is updated and processing
347    will resume at this point for the next call of inflate().
348
349  - Provide more output starting at next_out and update next_out and avail_out
350    accordingly.  inflate() provides as much output as possible, until there
351    is no more input data or no more space in the output buffer (see below
352    about the flush parameter).
353
354  Before the call of inflate(), the application should ensure that at least
355  one of the actions is possible, by providing more input and/or consuming
356  more output, and updating the next_* and avail_* values accordingly.
357  The application can consume the uncompressed output when it wants, for
358  example when the output buffer is full (avail_out == 0), or after each
359  call of inflate(). If inflate returns Z_OK and with zero avail_out, it
360  must be called again after making room in the output buffer because there
361  might be more output pending.
362
363    The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH,
364  Z_FINISH, or Z_BLOCK. Z_SYNC_FLUSH requests that inflate() flush as much
365  output as possible to the output buffer. Z_BLOCK requests that inflate() stop
366  if and when it get to the next deflate block boundary. When decoding the zlib
367  or gzip format, this will cause inflate() to return immediately after the
368  header and before the first block. When doing a raw inflate, inflate() will
369  go ahead and process the first block, and will return when it gets to the end
370  of that block, or when it runs out of data.
371
372    The Z_BLOCK option assists in appending to or combining deflate streams.
373  Also to assist in this, on return inflate() will set strm->data_type to the
374  number of unused bits in the last byte taken from strm->next_in, plus 64
375  if inflate() is currently decoding the last block in the deflate stream,
376  plus 128 if inflate() returned immediately after decoding an end-of-block
377  code or decoding the complete header up to just before the first byte of the
378  deflate stream. The end-of-block will not be indicated until all of the
379  uncompressed data from that block has been written to strm->next_out.  The
380  number of unused bits may in general be greater than seven, except when
381  bit 7 of data_type is set, in which case the number of unused bits will be
382  less than eight.
383
384    inflate() should normally be called until it returns Z_STREAM_END or an
385  error. However if all decompression is to be performed in a single step
386  (a single call of inflate), the parameter flush should be set to
387  Z_FINISH. In this case all pending input is processed and all pending
388  output is flushed; avail_out must be large enough to hold all the
389  uncompressed data. (The size of the uncompressed data may have been saved
390  by the compressor for this purpose.) The next operation on this stream must
391  be inflateEnd to deallocate the decompression state. The use of Z_FINISH
392  is never required, but can be used to inform inflate that a faster approach
393  may be used for the single inflate() call.
394
395     In this implementation, inflate() always flushes as much output as
396  possible to the output buffer, and always uses the faster approach on the
397  first call. So the only effect of the flush parameter in this implementation
398  is on the return value of inflate(), as noted below, or when it returns early
399  because Z_BLOCK is used.
400
401     If a preset dictionary is needed after this call (see inflateSetDictionary
402  below), inflate sets strm->adler to the adler32 checksum of the dictionary
403  chosen by the compressor and returns Z_NEED_DICT; otherwise it sets
404  strm->adler to the adler32 checksum of all output produced so far (that is,
405  total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described
406  below. At the end of the stream, inflate() checks that its computed adler32
407  checksum is equal to that saved by the compressor and returns Z_STREAM_END
408  only if the checksum is correct.
409
410    inflate() will decompress and check either zlib-wrapped or gzip-wrapped
411  deflate data.  The header type is detected automatically.  Any information
412  contained in the gzip header is not retained, so applications that need that
413  information should instead use raw inflate, see inflateInit2() below, or
414  inflateBack() and perform their own processing of the gzip header and
415  trailer.
416
417    inflate() returns Z_OK if some progress has been made (more input processed
418  or more output produced), Z_STREAM_END if the end of the compressed data has
419  been reached and all uncompressed output has been produced, Z_NEED_DICT if a
420  preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
421  corrupted (input stream not conforming to the zlib format or incorrect check
422  value), Z_STREAM_ERROR if the stream structure was inconsistent (for example
423  if next_in or next_out was NULL), Z_MEM_ERROR if there was not enough memory,
424  Z_BUF_ERROR if no progress is possible or if there was not enough room in the
425  output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and
426  inflate() can be called again with more input and more output space to
427  continue decompressing. If Z_DATA_ERROR is returned, the application may then
428  call inflateSync() to look for a good compression block if a partial recovery
429  of the data is desired.
430*/
431
432
433ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm));
434/*
435     All dynamically allocated data structures for this stream are freed.
436   This function discards any unprocessed input and does not flush any
437   pending output.
438
439     inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state
440   was inconsistent. In the error case, msg may be set but then points to a
441   static string (which must not be deallocated).
442*/
443
444                        /* Advanced functions */
445
446/*
447    The following functions are needed only in some special applications.
448*/
449
450/*
451ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm,
452                                     int  level,
453                                     int  method,
454                                     int  windowBits,
455                                     int  memLevel,
456                                     int  strategy));
457
458     This is another version of deflateInit with more compression options. The
459   fields next_in, zalloc, zfree and opaque must be initialized before by
460   the caller.
461
462     The method parameter is the compression method. It must be Z_DEFLATED in
463   this version of the library.
464
465     The windowBits parameter is the base two logarithm of the window size
466   (the size of the history buffer). It should be in the range 8..15 for this
467   version of the library. Larger values of this parameter result in better
468   compression at the expense of memory usage. The default value is 15 if
469   deflateInit is used instead.
470
471     windowBits can also be -8..-15 for raw deflate. In this case, -windowBits
472   determines the window size. deflate() will then generate raw deflate data
473   with no zlib header or trailer, and will not compute an adler32 check value.
474
475     windowBits can also be greater than 15 for optional gzip encoding. Add
476   16 to windowBits to write a simple gzip header and trailer around the
477   compressed data instead of a zlib wrapper. The gzip header will have no
478   file name, no extra data, no comment, no modification time (set to zero),
479   no header crc, and the operating system will be set to 255 (unknown).  If a
480   gzip stream is being written, strm->adler is a crc32 instead of an adler32.
481
482     The memLevel parameter specifies how much memory should be allocated
483   for the internal compression state. memLevel=1 uses minimum memory but
484   is slow and reduces compression ratio; memLevel=9 uses maximum memory
485   for optimal speed. The default value is 8. See zconf.h for total memory
486   usage as a function of windowBits and memLevel.
487
488     The strategy parameter is used to tune the compression algorithm. Use the
489   value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
490   filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no
491   string match), or Z_RLE to limit match distances to one (run-length
492   encoding). Filtered data consists mostly of small values with a somewhat
493   random distribution. In this case, the compression algorithm is tuned to
494   compress them better. The effect of Z_FILTERED is to force more Huffman
495   coding and less string matching; it is somewhat intermediate between
496   Z_DEFAULT and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as fast as
497   Z_HUFFMAN_ONLY, but give better compression for PNG image data. The strategy
498   parameter only affects the compression ratio but not the correctness of the
499   compressed output even if it is not set appropriately.
500
501      deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
502   memory, Z_STREAM_ERROR if a parameter is invalid (such as an invalid
503   method). msg is set to null if there is no error message.  deflateInit2 does
504   not perform any compression: this will be done by deflate().
505*/
506
507ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm,
508                                             const Bytef *dictionary,
509                                             uInt  dictLength));
510/*
511     Initializes the compression dictionary from the given byte sequence
512   without producing any compressed output. This function must be called
513   immediately after deflateInit, deflateInit2 or deflateReset, before any
514   call of deflate. The compressor and decompressor must use exactly the same
515   dictionary (see inflateSetDictionary).
516
517     The dictionary should consist of strings (byte sequences) that are likely
518   to be encountered later in the data to be compressed, with the most commonly
519   used strings preferably put towards the end of the dictionary. Using a
520   dictionary is most useful when the data to be compressed is short and can be
521   predicted with good accuracy; the data can then be compressed better than
522   with the default empty dictionary.
523
524     Depending on the size of the compression data structures selected by
525   deflateInit or deflateInit2, a part of the dictionary may in effect be
526   discarded, for example if the dictionary is larger than the window size in
527   deflate or deflate2. Thus the strings most likely to be useful should be
528   put at the end of the dictionary, not at the front.
529
530     Upon return of this function, strm->adler is set to the adler32 value
531   of the dictionary; the decompressor may later use this value to determine
532   which dictionary has been used by the compressor. (The adler32 value
533   applies to the whole dictionary even if only a subset of the dictionary is
534   actually used by the compressor.) If a raw deflate was requested, then the
535   adler32 value is not computed and strm->adler is not set.
536
537     deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
538   parameter is invalid (such as NULL dictionary) or the stream state is
539   inconsistent (for example if deflate has already been called for this stream
540   or if the compression method is bsort). deflateSetDictionary does not
541   perform any compression: this will be done by deflate().
542*/
543
544ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest,
545                                    z_streamp source));
546/*
547     Sets the destination stream as a complete copy of the source stream.
548
549     This function can be useful when several compression strategies will be
550   tried, for example when there are several ways of pre-processing the input
551   data with a filter. The streams that will be discarded should then be freed
552   by calling deflateEnd.  Note that deflateCopy duplicates the internal
553   compression state which can be quite large, so this strategy is slow and
554   can consume lots of memory.
555
556     deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
557   enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
558   (such as zalloc being NULL). msg is left unchanged in both source and
559   destination.
560*/
561
562ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm));
563/*
564     This function is equivalent to deflateEnd followed by deflateInit,
565   but does not free and reallocate all the internal compression state.
566   The stream will keep the same compression level and any other attributes
567   that may have been set by deflateInit2.
568
569      deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
570   stream state was inconsistent (such as zalloc or state being NULL).
571*/
572
573ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm,
574                                      int level,
575                                      int strategy));
576/*
577     Dynamically update the compression level and compression strategy.  The
578   interpretation of level and strategy is as in deflateInit2.  This can be
579   used to switch between compression and straight copy of the input data, or
580   to switch to a different kind of input data requiring a different
581   strategy. If the compression level is changed, the input available so far
582   is compressed with the old level (and may be flushed); the new level will
583   take effect only at the next call of deflate().
584
585     Before the call of deflateParams, the stream state must be set as for
586   a call of deflate(), since the currently available input may have to
587   be compressed and flushed. In particular, strm->avail_out must be non-zero.
588
589     deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source
590   stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR
591   if strm->avail_out was zero.
592*/
593
594ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm,
595                                       uLong sourceLen));
596/*
597     deflateBound() returns an upper bound on the compressed size after
598   deflation of sourceLen bytes.  It must be called after deflateInit()
599   or deflateInit2().  This would be used to allocate an output buffer
600   for deflation in a single pass, and so would be called before deflate().
601*/
602
603ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm,
604                                     int bits,
605                                     int value));
606/*
607     deflatePrime() inserts bits in the deflate output stream.  The intent
608  is that this function is used to start off the deflate output with the
609  bits leftover from a previous deflate stream when appending to it.  As such,
610  this function can only be used for raw deflate, and must be used before the
611  first deflate() call after a deflateInit2() or deflateReset().  bits must be
612  less than or equal to 16, and that many of the least significant bits of
613  value will be inserted in the output.
614
615      deflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source
616   stream state was inconsistent.
617*/
618
619/*
620ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm,
621                                     int  windowBits));
622
623     This is another version of inflateInit with an extra parameter. The
624   fields next_in, avail_in, zalloc, zfree and opaque must be initialized
625   before by the caller.
626
627     The windowBits parameter is the base two logarithm of the maximum window
628   size (the size of the history buffer).  It should be in the range 8..15 for
629   this version of the library. The default value is 15 if inflateInit is used
630   instead. windowBits must be greater than or equal to the windowBits value
631   provided to deflateInit2() while compressing, or it must be equal to 15 if
632   deflateInit2() was not used. If a compressed stream with a larger window
633   size is given as input, inflate() will return with the error code
634   Z_DATA_ERROR instead of trying to allocate a larger window.
635
636     windowBits can also be -8..-15 for raw inflate. In this case, -windowBits
637   determines the window size. inflate() will then process raw deflate data,
638   not looking for a zlib or gzip header, not generating a check value, and not
639   looking for any check values for comparison at the end of the stream. This
640   is for use with other formats that use the deflate compressed data format
641   such as zip.  Those formats provide their own check values. If a custom
642   format is developed using the raw deflate format for compressed data, it is
643   recommended that a check value such as an adler32 or a crc32 be applied to
644   the uncompressed data as is done in the zlib, gzip, and zip formats.  For
645   most applications, the zlib format should be used as is. Note that comments
646   above on the use in deflateInit2() applies to the magnitude of windowBits.
647
648     windowBits can also be greater than 15 for optional gzip decoding. Add
649   32 to windowBits to enable zlib and gzip decoding with automatic header
650   detection, or add 16 to decode only the gzip format (the zlib format will
651   return a Z_DATA_ERROR.  If a gzip stream is being decoded, strm->adler is
652   a crc32 instead of an adler32.
653
654     inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
655   memory, Z_STREAM_ERROR if a parameter is invalid (such as a negative
656   memLevel). msg is set to null if there is no error message.  inflateInit2
657   does not perform any decompression apart from reading the zlib header if
658   present: this will be done by inflate(). (So next_in and avail_in may be
659   modified, but next_out and avail_out are unchanged.)
660*/
661
662ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm,
663                                             const Bytef *dictionary,
664                                             uInt  dictLength));
665/*
666     Initializes the decompression dictionary from the given uncompressed byte
667   sequence. This function must be called immediately after a call of inflate
668   if this call returned Z_NEED_DICT. The dictionary chosen by the compressor
669   can be determined from the adler32 value returned by this call of
670   inflate. The compressor and decompressor must use exactly the same
671   dictionary (see deflateSetDictionary).
672
673     inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
674   parameter is invalid (such as NULL dictionary) or the stream state is
675   inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
676   expected one (incorrect adler32 value). inflateSetDictionary does not
677   perform any decompression: this will be done by subsequent calls of
678   inflate().
679*/
680
681ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm));
682/*
683    Skips invalid compressed data until a full flush point (see above the
684  description of deflate with Z_FULL_FLUSH) can be found, or until all
685  available input is skipped. No output is provided.
686
687    inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR
688  if no more input was provided, Z_DATA_ERROR if no flush point has been found,
689  or Z_STREAM_ERROR if the stream structure was inconsistent. In the success
690  case, the application may save the current current value of total_in which
691  indicates where valid compressed data was found. In the error case, the
692  application may repeatedly call inflateSync, providing more input each time,
693  until success or end of the input data.
694*/
695
696ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest,
697                                    z_streamp source));
698/*
699     Sets the destination stream as a complete copy of the source stream.
700
701     This function can be useful when randomly accessing a large stream.  The
702   first pass through the stream can periodically record the inflate state,
703   allowing restarting inflate at those points when randomly accessing the
704   stream.
705
706     inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
707   enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
708   (such as zalloc being NULL). msg is left unchanged in both source and
709   destination.
710*/
711
712ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm));
713/*
714     This function is equivalent to inflateEnd followed by inflateInit,
715   but does not free and reallocate all the internal decompression state.
716   The stream will keep attributes that may have been set by inflateInit2.
717
718      inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
719   stream state was inconsistent (such as zalloc or state being NULL).
720*/
721
722/*
723ZEXTERN int ZEXPORT inflateBackInit OF((z_stream FAR *strm, int windowBits,
724                                        unsigned char FAR *window));
725
726     Initialize the internal stream state for decompression using inflateBack()
727   calls.  The fields zalloc, zfree and opaque in strm must be initialized
728   before the call.  If zalloc and zfree are Z_NULL, then the default library-
729   derived memory allocation routines are used.  windowBits is the base two
730   logarithm of the window size, in the range 8..15.  window is a caller
731   supplied buffer of that size.  Except for special applications where it is
732   assured that deflate was used with small window sizes, windowBits must be 15
733   and a 32K byte window must be supplied to be able to decompress general
734   deflate streams.
735
736     See inflateBack() for the usage of these routines.
737
738     inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of
739   the paramaters are invalid, Z_MEM_ERROR if the internal state could not
740   be allocated, or Z_VERSION_ERROR if the version of the library does not
741   match the version of the header file.
742*/
743
744typedef unsigned (*in_func) OF((void FAR *, unsigned char FAR * FAR *));
745typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned));
746
747ZEXTERN int ZEXPORT inflateBack OF((z_stream FAR *strm,
748                                    in_func in, void FAR *in_desc,
749                                    out_func out, void FAR *out_desc));
750/*
751     inflateBack() does a raw inflate with a single call using a call-back
752   interface for input and output.  This is more efficient than inflate() for
753   file i/o applications in that it avoids copying between the output and the
754   sliding window by simply making the window itself the output buffer.  This
755   function trusts the application to not change the output buffer passed by
756   the output function, at least until inflateBack() returns.
757
758     inflateBackInit() must be called first to allocate the internal state
759   and to initialize the state with the user-provided window buffer.
760   inflateBack() may then be used multiple times to inflate a complete, raw
761   deflate stream with each call.  inflateBackEnd() is then called to free
762   the allocated state.
763
764     A raw deflate stream is one with no zlib or gzip header or trailer.
765   This routine would normally be used in a utility that reads zip or gzip
766   files and writes out uncompressed files.  The utility would decode the
767   header and process the trailer on its own, hence this routine expects
768   only the raw deflate stream to decompress.  This is different from the
769   normal behavior of inflate(), which expects either a zlib or gzip header and
770   trailer around the deflate stream.
771
772     inflateBack() uses two subroutines supplied by the caller that are then
773   called by inflateBack() for input and output.  inflateBack() calls those
774   routines until it reads a complete deflate stream and writes out all of the
775   uncompressed data, or until it encounters an error.  The function's
776   parameters and return types are defined above in the in_func and out_func
777   typedefs.  inflateBack() will call in(in_desc, &buf) which should return the
778   number of bytes of provided input, and a pointer to that input in buf.  If
779   there is no input available, in() must return zero--buf is ignored in that
780   case--and inflateBack() will return a buffer error.  inflateBack() will call
781   out(out_desc, buf, len) to write the uncompressed data buf[0..len-1].  out()
782   should return zero on success, or non-zero on failure.  If out() returns
783   non-zero, inflateBack() will return with an error.  Neither in() nor out()
784   are permitted to change the contents of the window provided to
785   inflateBackInit(), which is also the buffer that out() uses to write from.
786   The length written by out() will be at most the window size.  Any non-zero
787   amount of input may be provided by in().
788
789     For convenience, inflateBack() can be provided input on the first call by
790   setting strm->next_in and strm->avail_in.  If that input is exhausted, then
791   in() will be called.  Therefore strm->next_in must be initialized before
792   calling inflateBack().  If strm->next_in is Z_NULL, then in() will be called
793   immediately for input.  If strm->next_in is not Z_NULL, then strm->avail_in
794   must also be initialized, and then if strm->avail_in is not zero, input will
795   initially be taken from strm->next_in[0 .. strm->avail_in - 1].
796
797     The in_desc and out_desc parameters of inflateBack() is passed as the
798   first parameter of in() and out() respectively when they are called.  These
799   descriptors can be optionally used to pass any information that the caller-
800   supplied in() and out() functions need to do their job.
801
802     On return, inflateBack() will set strm->next_in and strm->avail_in to
803   pass back any unused input that was provided by the last in() call.  The
804   return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR
805   if in() or out() returned an error, Z_DATA_ERROR if there was a format
806   error in the deflate stream (in which case strm->msg is set to indicate the
807   nature of the error), or Z_STREAM_ERROR if the stream was not properly
808   initialized.  In the case of Z_BUF_ERROR, an input or output error can be
809   distinguished using strm->next_in which will be Z_NULL only if in() returned
810   an error.  If strm->next is not Z_NULL, then the Z_BUF_ERROR was due to
811   out() returning non-zero.  (in() will always be called before out(), so
812   strm->next_in is assured to be defined if out() returns non-zero.)  Note
813   that inflateBack() cannot return Z_OK.
814*/
815
816ZEXTERN int ZEXPORT inflateBackEnd OF((z_stream FAR *strm));
817/*
818     All memory allocated by inflateBackInit() is freed.
819
820     inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream
821   state was inconsistent.
822*/
823
824ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void));
825/* Return flags indicating compile-time options.
826
827    Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other:
828     1.0: size of uInt
829     3.2: size of uLong
830     5.4: size of voidpf (pointer)
831     7.6: size of z_off_t
832
833    Compiler, assembler, and debug options:
834     8: DEBUG
835     9: ASMV or ASMINF -- use ASM code
836     10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention
837     11: 0 (reserved)
838
839    One-time table building (smaller code, but not thread-safe if true):
840     12: BUILDFIXED -- build static block decoding tables when needed
841     13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed
842     14,15: 0 (reserved)
843
844    Library content (indicates missing functionality):
845     16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking
846                          deflate code when not needed)
847     17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect
848                    and decode gzip streams (to avoid linking crc code)
849     18-19: 0 (reserved)
850
851    Operation variations (changes in library functionality):
852     20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate
853     21: FASTEST -- deflate algorithm with only one, lowest compression level
854     22,23: 0 (reserved)
855
856    The sprintf variant used by gzprintf (zero is best):
857     24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format
858     25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure!
859     26: 0 = returns value, 1 = void -- 1 means inferred string length returned
860
861    Remainder:
862     27-31: 0 (reserved)
863 */
864
865
866                        /* utility functions */
867
868/*
869     The following utility functions are implemented on top of the
870   basic stream-oriented functions. To simplify the interface, some
871   default options are assumed (compression level and memory usage,
872   standard memory allocation functions). The source code of these
873   utility functions can easily be modified if you need special options.
874*/
875
876ZEXTERN int ZEXPORT compress OF((Bytef *dest,   uLongf *destLen,
877                                 const Bytef *source, uLong sourceLen));
878/*
879     Compresses the source buffer into the destination buffer.  sourceLen is
880   the byte length of the source buffer. Upon entry, destLen is the total
881   size of the destination buffer, which must be at least the value returned
882   by compressBound(sourceLen). Upon exit, destLen is the actual size of the
883   compressed buffer.
884     This function can be used to compress a whole file at once if the
885   input file is mmap'ed.
886     compress returns Z_OK if success, Z_MEM_ERROR if there was not
887   enough memory, Z_BUF_ERROR if there was not enough room in the output
888   buffer.
889*/
890
891ZEXTERN int ZEXPORT compress2 OF((Bytef *dest,   uLongf *destLen,
892                                  const Bytef *source, uLong sourceLen,
893                                  int level));
894/*
895     Compresses the source buffer into the destination buffer. The level
896   parameter has the same meaning as in deflateInit.  sourceLen is the byte
897   length of the source buffer. Upon entry, destLen is the total size of the
898   destination buffer, which must be at least the value returned by
899   compressBound(sourceLen). Upon exit, destLen is the actual size of the
900   compressed buffer.
901
902     compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
903   memory, Z_BUF_ERROR if there was not enough room in the output buffer,
904   Z_STREAM_ERROR if the level parameter is invalid.
905*/
906
907ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen));
908/*
909     compressBound() returns an upper bound on the compressed size after
910   compress() or compress2() on sourceLen bytes.  It would be used before
911   a compress() or compress2() call to allocate the destination buffer.
912*/
913
914ZEXTERN int ZEXPORT uncompress OF((Bytef *dest,   uLongf *destLen,
915                                   const Bytef *source, uLong sourceLen));
916/*
917     Decompresses the source buffer into the destination buffer.  sourceLen is
918   the byte length of the source buffer. Upon entry, destLen is the total
919   size of the destination buffer, which must be large enough to hold the
920   entire uncompressed data. (The size of the uncompressed data must have
921   been saved previously by the compressor and transmitted to the decompressor
922   by some mechanism outside the scope of this compression library.)
923   Upon exit, destLen is the actual size of the compressed buffer.
924     This function can be used to decompress a whole file at once if the
925   input file is mmap'ed.
926
927     uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
928   enough memory, Z_BUF_ERROR if there was not enough room in the output
929   buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete.
930*/
931
932
933typedef voidp gzFile;
934
935ZEXTERN gzFile ZEXPORT gzopen  OF((const char *path, const char *mode));
936/*
937     Opens a gzip (.gz) file for reading or writing. The mode parameter
938   is as in fopen ("rb" or "wb") but can also include a compression level
939   ("wb9") or a strategy: 'f' for filtered data as in "wb6f", 'h' for
940   Huffman only compression as in "wb1h", or 'R' for run-length encoding
941   as in "wb1R". (See the description of deflateInit2 for more information
942   about the strategy parameter.)
943
944     gzopen can be used to read a file which is not in gzip format; in this
945   case gzread will directly read from the file without decompression.
946
947     gzopen returns NULL if the file could not be opened or if there was
948   insufficient memory to allocate the (de)compression state; errno
949   can be checked to distinguish the two cases (if errno is zero, the
950   zlib error is Z_MEM_ERROR).  */
951
952ZEXTERN gzFile ZEXPORT gzdopen  OF((int fd, const char *mode));
953/*
954     gzdopen() associates a gzFile with the file descriptor fd.  File
955   descriptors are obtained from calls like open, dup, creat, pipe or
956   fileno (in the file has been previously opened with fopen).
957   The mode parameter is as in gzopen.
958     The next call of gzclose on the returned gzFile will also close the
959   file descriptor fd, just like fclose(fdopen(fd), mode) closes the file
960   descriptor fd. If you want to keep fd open, use gzdopen(dup(fd), mode).
961     gzdopen returns NULL if there was insufficient memory to allocate
962   the (de)compression state.
963*/
964
965ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy));
966/*
967     Dynamically update the compression level or strategy. See the description
968   of deflateInit2 for the meaning of these parameters.
969     gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not
970   opened for writing.
971*/
972
973ZEXTERN int ZEXPORT    gzread  OF((gzFile file, voidp buf, unsigned len));
974/*
975     Reads the given number of uncompressed bytes from the compressed file.
976   If the input file was not in gzip format, gzread copies the given number
977   of bytes into the buffer.
978     gzread returns the number of uncompressed bytes actually read (0 for
979   end of file, -1 for error). */
980
981ZEXTERN int ZEXPORT    gzwrite OF((gzFile file,
982                                   voidpc buf, unsigned len));
983/*
984     Writes the given number of uncompressed bytes into the compressed file.
985   gzwrite returns the number of uncompressed bytes actually written
986   (0 in case of error).
987*/
988
989ZEXTERN int ZEXPORTVA   gzprintf OF((gzFile file, const char *format, ...));
990/*
991     Converts, formats, and writes the args to the compressed file under
992   control of the format string, as in fprintf. gzprintf returns the number of
993   uncompressed bytes actually written (0 in case of error).  The number of
994   uncompressed bytes written is limited to 4095. The caller should assure that
995   this limit is not exceeded. If it is exceeded, then gzprintf() will return
996   return an error (0) with nothing written. In this case, there may also be a
997   buffer overflow with unpredictable consequences, which is possible only if
998   zlib was compiled with the insecure functions sprintf() or vsprintf()
999   because the secure snprintf() or vsnprintf() functions were not available.
1000*/
1001
1002ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s));
1003/*
1004      Writes the given null-terminated string to the compressed file, excluding
1005   the terminating null character.
1006      gzputs returns the number of characters written, or -1 in case of error.
1007*/
1008
1009ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len));
1010/*
1011      Reads bytes from the compressed file until len-1 characters are read, or
1012   a newline character is read and transferred to buf, or an end-of-file
1013   condition is encountered.  The string is then terminated with a null
1014   character.
1015      gzgets returns buf, or Z_NULL in case of error.
1016*/
1017
1018ZEXTERN int ZEXPORT    gzputc OF((gzFile file, int c));
1019/*
1020      Writes c, converted to an unsigned char, into the compressed file.
1021   gzputc returns the value that was written, or -1 in case of error.
1022*/
1023
1024ZEXTERN int ZEXPORT    gzgetc OF((gzFile file));
1025/*
1026      Reads one byte from the compressed file. gzgetc returns this byte
1027   or -1 in case of end of file or error.
1028*/
1029
1030ZEXTERN int ZEXPORT    gzungetc OF((int c, gzFile file));
1031/*
1032      Push one character back onto the stream to be read again later.
1033   Only one character of push-back is allowed.  gzungetc() returns the
1034   character pushed, or -1 on failure.  gzungetc() will fail if a
1035   character has been pushed but not read yet, or if c is -1. The pushed
1036   character will be discarded if the stream is repositioned with gzseek()
1037   or gzrewind().
1038*/
1039
1040ZEXTERN int ZEXPORT    gzflush OF((gzFile file, int flush));
1041/*
1042     Flushes all pending output into the compressed file. The parameter
1043   flush is as in the deflate() function. The return value is the zlib
1044   error number (see function gzerror below). gzflush returns Z_OK if
1045   the flush parameter is Z_FINISH and all output could be flushed.
1046     gzflush should be called only when strictly necessary because it can
1047   degrade compression.
1048*/
1049
1050ZEXTERN z_off_t ZEXPORT    gzseek OF((gzFile file,
1051                                      z_off_t offset, int whence));
1052/*
1053      Sets the starting position for the next gzread or gzwrite on the
1054   given compressed file. The offset represents a number of bytes in the
1055   uncompressed data stream. The whence parameter is defined as in lseek(2);
1056   the value SEEK_END is not supported.
1057     If the file is opened for reading, this function is emulated but can be
1058   extremely slow. If the file is opened for writing, only forward seeks are
1059   supported; gzseek then compresses a sequence of zeroes up to the new
1060   starting position.
1061
1062      gzseek returns the resulting offset location as measured in bytes from
1063   the beginning of the uncompressed stream, or -1 in case of error, in
1064   particular if the file is opened for writing and the new starting position
1065   would be before the current position.
1066*/
1067
1068ZEXTERN int ZEXPORT    gzrewind OF((gzFile file));
1069/*
1070     Rewinds the given file. This function is supported only for reading.
1071
1072   gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET)
1073*/
1074
1075ZEXTERN z_off_t ZEXPORT    gztell OF((gzFile file));
1076/*
1077     Returns the starting position for the next gzread or gzwrite on the
1078   given compressed file. This position represents a number of bytes in the
1079   uncompressed data stream.
1080
1081   gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)
1082*/
1083
1084ZEXTERN int ZEXPORT gzeof OF((gzFile file));
1085/*
1086     Returns 1 when EOF has previously been detected reading the given
1087   input stream, otherwise zero.
1088*/
1089
1090ZEXTERN int ZEXPORT    gzclose OF((gzFile file));
1091/*
1092     Flushes all pending output if necessary, closes the compressed file
1093   and deallocates all the (de)compression state. The return value is the zlib
1094   error number (see function gzerror below).
1095*/
1096
1097ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum));
1098/*
1099     Returns the error message for the last error which occurred on the
1100   given compressed file. errnum is set to zlib error number. If an
1101   error occurred in the file system and not in the compression library,
1102   errnum is set to Z_ERRNO and the application may consult errno
1103   to get the exact error code.
1104*/
1105
1106ZEXTERN void ZEXPORT gzclearerr OF((gzFile file));
1107/*
1108     Clears the error and end-of-file flags for file. This is analogous to the
1109   clearerr() function in stdio. This is useful for continuing to read a gzip
1110   file that is being written concurrently.
1111*/
1112
1113                        /* checksum functions */
1114
1115/*
1116     These functions are not related to compression but are exported
1117   anyway because they might be useful in applications using the
1118   compression library.
1119*/
1120
1121ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len));
1122
1123/*
1124     Update a running Adler-32 checksum with the bytes buf[0..len-1] and
1125   return the updated checksum. If buf is NULL, this function returns
1126   the required initial value for the checksum.
1127   An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
1128   much faster. Usage example:
1129
1130     uLong adler = adler32(0L, Z_NULL, 0);
1131
1132     while (read_buffer(buffer, length) != EOF) {
1133       adler = adler32(adler, buffer, length);
1134     }
1135     if (adler != original_adler) error();
1136*/
1137
1138ZEXTERN uLong ZEXPORT crc32   OF((uLong crc, const Bytef *buf, uInt len));
1139/*
1140     Update a running crc with the bytes buf[0..len-1] and return the updated
1141   crc. If buf is NULL, this function returns the required initial value
1142   for the crc. Pre- and post-conditioning (one's complement) is performed
1143   within this function so it shouldn't be done by the application.
1144   Usage example:
1145
1146     uLong crc = crc32(0L, Z_NULL, 0);
1147
1148     while (read_buffer(buffer, length) != EOF) {
1149       crc = crc32(crc, buffer, length);
1150     }
1151     if (crc != original_crc) error();
1152*/
1153
1154
1155                        /* various hacks, don't look :) */
1156
1157/* deflateInit and inflateInit are macros to allow checking the zlib version
1158 * and the compiler's view of z_stream:
1159 */
1160ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level,
1161                                     const char *version, int stream_size));
1162ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm,
1163                                     const char *version, int stream_size));
1164ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int  level, int  method,
1165                                      int windowBits, int memLevel,
1166                                      int strategy, const char *version,
1167                                      int stream_size));
1168ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int  windowBits,
1169                                      const char *version, int stream_size));
1170ZEXTERN int ZEXPORT inflateBackInit_ OF((z_stream FAR *strm, int windowBits,
1171                                         unsigned char FAR *window,
1172                                         const char *version,
1173                                         int stream_size));
1174#define deflateInit(strm, level) \
1175        deflateInit_((strm), (level),       ZLIB_VERSION, sizeof(z_stream))
1176#define inflateInit(strm) \
1177        inflateInit_((strm),                ZLIB_VERSION, sizeof(z_stream))
1178#define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
1179        deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
1180                      (strategy),           ZLIB_VERSION, sizeof(z_stream))
1181#define inflateInit2(strm, windowBits) \
1182        inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream))
1183#define inflateBackInit(strm, windowBits, window) \
1184        inflateBackInit_((strm), (windowBits), (window), \
1185        ZLIB_VERSION, sizeof(z_stream))
1186
1187#if !defined(_ZUTIL_H) && !defined(NO_DUMMY_DECL)
1188    struct internal_state {int dummy;}; /* hack for buggy compilers */
1189#endif
1190
1191ZEXTERN const char   * ZEXPORT zError           OF((int));
1192ZEXTERN int            ZEXPORT inflateSyncPoint OF((z_streamp z));
1193ZEXTERN const uLongf * ZEXPORT get_crc_table    OF((void));
1194
1195#ifdef __cplusplus
1196}
1197#endif
1198
1199#endif /* _ZLIB_H */
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