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zlib.h
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1 /* zlib.h -- interface of the 'zlib' general purpose compression library
2  version 1.1.4, March 11th, 2002
3 
4  Copyright (C) 1995-2002 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 "ftzconf.h"
35 
36 #ifdef __cplusplus
37 extern "C" {
38 #endif
39 
40 #define ZLIB_VERSION "1.1.4"
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 
63 typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size));
64 typedef void (*free_func) OF((voidpf opaque, voidpf address));
65 
66 struct internal_state;
67 
68 typedef 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 
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 
167  /* basic functions */
168 
169 /* The application can compare zlibVersion and ZLIB_VERSION for consistency.
170  If the first character differs, the library code actually used is
171  not compatible with the zlib.h header file used by the application.
172  This check is automatically made by deflateInit and inflateInit.
173  */
174 
175 /*
176 ZEXTERN(int) deflateInit OF((z_streamp strm, int level));
177 
178  Initializes the internal stream state for compression. The fields
179  zalloc, zfree and opaque must be initialized before by the caller.
180  If zalloc and zfree are set to Z_NULL, deflateInit updates them to
181  use default allocation functions.
182 
183  The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
184  1 gives best speed, 9 gives best compression, 0 gives no compression at
185  all (the input data is simply copied a block at a time).
186  Z_DEFAULT_COMPRESSION requests a default compromise between speed and
187  compression (currently equivalent to level 6).
188 
189  deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not
190  enough memory, Z_STREAM_ERROR if level is not a valid compression level,
191  Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
192  with the version assumed by the caller (ZLIB_VERSION).
193  msg is set to null if there is no error message. deflateInit does not
194  perform any compression: this will be done by deflate().
195 */
196 
197 
198 /*
199  deflate compresses as much data as possible, and stops when the input
200  buffer becomes empty or the output buffer becomes full. It may introduce some
201  output latency (reading input without producing any output) except when
202  forced to flush.
203 
204  The detailed semantics are as follows. deflate performs one or both of the
205  following actions:
206 
207  - Compress more input starting at next_in and update next_in and avail_in
208  accordingly. If not all input can be processed (because there is not
209  enough room in the output buffer), next_in and avail_in are updated and
210  processing will resume at this point for the next call of deflate().
211 
212  - Provide more output starting at next_out and update next_out and avail_out
213  accordingly. This action is forced if the parameter flush is non zero.
214  Forcing flush frequently degrades the compression ratio, so this parameter
215  should be set only when necessary (in interactive applications).
216  Some output may be provided even if flush is not set.
217 
218  Before the call of deflate(), the application should ensure that at least
219  one of the actions is possible, by providing more input and/or consuming
220  more output, and updating avail_in or avail_out accordingly; avail_out
221  should never be zero before the call. The application can consume the
222  compressed output when it wants, for example when the output buffer is full
223  (avail_out == 0), or after each call of deflate(). If deflate returns Z_OK
224  and with zero avail_out, it must be called again after making room in the
225  output buffer because there might be more output pending.
226 
227  If the parameter flush is set to Z_SYNC_FLUSH, all pending output is
228  flushed to the output buffer and the output is aligned on a byte boundary, so
229  that the decompressor can get all input data available so far. (In particular
230  avail_in is zero after the call if enough output space has been provided
231  before the call.) Flushing may degrade compression for some compression
232  algorithms and so it should be used only when necessary.
233 
234  If flush is set to Z_FULL_FLUSH, all output is flushed as with
235  Z_SYNC_FLUSH, and the compression state is reset so that decompression can
236  restart from this point if previous compressed data has been damaged or if
237  random access is desired. Using Z_FULL_FLUSH too often can seriously degrade
238  the compression.
239 
240  If deflate returns with avail_out == 0, this function must be called again
241  with the same value of the flush parameter and more output space (updated
242  avail_out), until the flush is complete (deflate returns with non-zero
243  avail_out).
244 
245  If the parameter flush is set to Z_FINISH, pending input is processed,
246  pending output is flushed and deflate returns with Z_STREAM_END if there
247  was enough output space; if deflate returns with Z_OK, this function must be
248  called again with Z_FINISH and more output space (updated avail_out) but no
249  more input data, until it returns with Z_STREAM_END or an error. After
250  deflate has returned Z_STREAM_END, the only possible operations on the
251  stream are deflateReset or deflateEnd.
252 
253  Z_FINISH can be used immediately after deflateInit if all the compression
254  is to be done in a single step. In this case, avail_out must be at least
255  0.1% larger than avail_in plus 12 bytes. If deflate does not return
256  Z_STREAM_END, then it must be called again as described above.
257 
258  deflate() sets strm->adler to the adler32 checksum of all input read
259  so far (that is, total_in bytes).
260 
261  deflate() may update data_type if it can make a good guess about
262  the input data type (Z_ASCII or Z_BINARY). In doubt, the data is considered
263  binary. This field is only for information purposes and does not affect
264  the compression algorithm in any manner.
265 
266  deflate() returns Z_OK if some progress has been made (more input
267  processed or more output produced), Z_STREAM_END if all input has been
268  consumed and all output has been produced (only when flush is set to
269  Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
270  if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible
271  (for example avail_in or avail_out was zero).
272 */
273 
274 
275 /*
276  All dynamically allocated data structures for this stream are freed.
277  This function discards any unprocessed input and does not flush any
278  pending output.
279 
280  deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
281  stream state was inconsistent, Z_DATA_ERROR if the stream was freed
282  prematurely (some input or output was discarded). In the error case,
283  msg may be set but then points to a static string (which must not be
284  deallocated).
285 */
286 
287 
288 /*
289 ZEXTERN(int) inflateInit OF((z_streamp strm));
290 
291  Initializes the internal stream state for decompression. The fields
292  next_in, avail_in, zalloc, zfree and opaque must be initialized before by
293  the caller. If next_in is not Z_NULL and avail_in is large enough (the exact
294  value depends on the compression method), inflateInit determines the
295  compression method from the zlib header and allocates all data structures
296  accordingly; otherwise the allocation will be deferred to the first call of
297  inflate. If zalloc and zfree are set to Z_NULL, inflateInit updates them to
298  use default allocation functions.
299 
300  inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
301  memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
302  version assumed by the caller. msg is set to null if there is no error
303  message. inflateInit does not perform any decompression apart from reading
304  the zlib header if present: this will be done by inflate(). (So next_in and
305  avail_in may be modified, but next_out and avail_out are unchanged.)
306 */
307 
308 
310 /*
311  inflate decompresses as much data as possible, and stops when the input
312  buffer becomes empty or the output buffer becomes full. It may some
313  introduce some output latency (reading input without producing any output)
314  except when forced to flush.
315 
316  The detailed semantics are as follows. inflate performs one or both of the
317  following actions:
318 
319  - Decompress more input starting at next_in and update next_in and avail_in
320  accordingly. If not all input can be processed (because there is not
321  enough room in the output buffer), next_in is updated and processing
322  will resume at this point for the next call of inflate().
323 
324  - Provide more output starting at next_out and update next_out and avail_out
325  accordingly. inflate() provides as much output as possible, until there
326  is no more input data or no more space in the output buffer (see below
327  about the flush parameter).
328 
329  Before the call of inflate(), the application should ensure that at least
330  one of the actions is possible, by providing more input and/or consuming
331  more output, and updating the next_* and avail_* values accordingly.
332  The application can consume the uncompressed output when it wants, for
333  example when the output buffer is full (avail_out == 0), or after each
334  call of inflate(). If inflate returns Z_OK and with zero avail_out, it
335  must be called again after making room in the output buffer because there
336  might be more output pending.
337 
338  If the parameter flush is set to Z_SYNC_FLUSH, inflate flushes as much
339  output as possible to the output buffer. The flushing behavior of inflate is
340  not specified for values of the flush parameter other than Z_SYNC_FLUSH
341  and Z_FINISH, but the current implementation actually flushes as much output
342  as possible anyway.
343 
344  inflate() should normally be called until it returns Z_STREAM_END or an
345  error. However if all decompression is to be performed in a single step
346  (a single call of inflate), the parameter flush should be set to
347  Z_FINISH. In this case all pending input is processed and all pending
348  output is flushed; avail_out must be large enough to hold all the
349  uncompressed data. (The size of the uncompressed data may have been saved
350  by the compressor for this purpose.) The next operation on this stream must
351  be inflateEnd to deallocate the decompression state. The use of Z_FINISH
352  is never required, but can be used to inform inflate that a faster routine
353  may be used for the single inflate() call.
354 
355  If a preset dictionary is needed at this point (see inflateSetDictionary
356  below), inflate sets strm-adler to the adler32 checksum of the
357  dictionary chosen by the compressor and returns Z_NEED_DICT; otherwise
358  it sets strm->adler to the adler32 checksum of all output produced
359  so far (that is, total_out bytes) and returns Z_OK, Z_STREAM_END or
360  an error code as described below. At the end of the stream, inflate()
361  checks that its computed adler32 checksum is equal to that saved by the
362  compressor and returns Z_STREAM_END only if the checksum is correct.
363 
364  inflate() returns Z_OK if some progress has been made (more input processed
365  or more output produced), Z_STREAM_END if the end of the compressed data has
366  been reached and all uncompressed output has been produced, Z_NEED_DICT if a
367  preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
368  corrupted (input stream not conforming to the zlib format or incorrect
369  adler32 checksum), Z_STREAM_ERROR if the stream structure was inconsistent
370  (for example if next_in or next_out was NULL), Z_MEM_ERROR if there was not
371  enough memory, Z_BUF_ERROR if no progress is possible or if there was not
372  enough room in the output buffer when Z_FINISH is used. In the Z_DATA_ERROR
373  case, the application may then call inflateSync to look for a good
374  compression block.
375 */
376 
377 
379 /*
380  All dynamically allocated data structures for this stream are freed.
381  This function discards any unprocessed input and does not flush any
382  pending output.
383 
384  inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state
385  was inconsistent. In the error case, msg may be set but then points to a
386  static string (which must not be deallocated).
387 */
388 
389  /* Advanced functions */
390 
391 /*
392  The following functions are needed only in some special applications.
393 */
394 
395 /*
396 ZEXTERN(int) deflateInit2 OF((z_streamp strm,
397  int level,
398  int method,
399  int windowBits,
400  int memLevel,
401  int strategy));
402 
403  This is another version of deflateInit with more compression options. The
404  fields next_in, zalloc, zfree and opaque must be initialized before by
405  the caller.
406 
407  The method parameter is the compression method. It must be Z_DEFLATED in
408  this version of the library.
409 
410  The windowBits parameter is the base two logarithm of the window size
411  (the size of the history buffer). It should be in the range 8..15 for this
412  version of the library. Larger values of this parameter result in better
413  compression at the expense of memory usage. The default value is 15 if
414  deflateInit is used instead.
415 
416  The memLevel parameter specifies how much memory should be allocated
417  for the internal compression state. memLevel=1 uses minimum memory but
418  is slow and reduces compression ratio; memLevel=9 uses maximum memory
419  for optimal speed. The default value is 8. See zconf.h for total memory
420  usage as a function of windowBits and memLevel.
421 
422  The strategy parameter is used to tune the compression algorithm. Use the
423  value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
424  filter (or predictor), or Z_HUFFMAN_ONLY to force Huffman encoding only (no
425  string match). Filtered data consists mostly of small values with a
426  somewhat random distribution. In this case, the compression algorithm is
427  tuned to compress them better. The effect of Z_FILTERED is to force more
428  Huffman coding and less string matching; it is somewhat intermediate
429  between Z_DEFAULT and Z_HUFFMAN_ONLY. The strategy parameter only affects
430  the compression ratio but not the correctness of the compressed output even
431  if it is not set appropriately.
432 
433  deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
434  memory, Z_STREAM_ERROR if a parameter is invalid (such as an invalid
435  method). msg is set to null if there is no error message. deflateInit2 does
436  not perform any compression: this will be done by deflate().
437 */
438 
439 /*
440  Initializes the compression dictionary from the given byte sequence
441  without producing any compressed output. This function must be called
442  immediately after deflateInit, deflateInit2 or deflateReset, before any
443  call of deflate. The compressor and decompressor must use exactly the same
444  dictionary (see inflateSetDictionary).
445 
446  The dictionary should consist of strings (byte sequences) that are likely
447  to be encountered later in the data to be compressed, with the most commonly
448  used strings preferably put towards the end of the dictionary. Using a
449  dictionary is most useful when the data to be compressed is short and can be
450  predicted with good accuracy; the data can then be compressed better than
451  with the default empty dictionary.
452 
453  Depending on the size of the compression data structures selected by
454  deflateInit or deflateInit2, a part of the dictionary may in effect be
455  discarded, for example if the dictionary is larger than the window size in
456  deflate or deflate2. Thus the strings most likely to be useful should be
457  put at the end of the dictionary, not at the front.
458 
459  Upon return of this function, strm->adler is set to the Adler32 value
460  of the dictionary; the decompressor may later use this value to determine
461  which dictionary has been used by the compressor. (The Adler32 value
462  applies to the whole dictionary even if only a subset of the dictionary is
463  actually used by the compressor.)
464 
465  deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
466  parameter is invalid (such as NULL dictionary) or the stream state is
467  inconsistent (for example if deflate has already been called for this stream
468  or if the compression method is bsort). deflateSetDictionary does not
469  perform any compression: this will be done by deflate().
470 */
471 
472 /*
473  Sets the destination stream as a complete copy of the source stream.
474 
475  This function can be useful when several compression strategies will be
476  tried, for example when there are several ways of pre-processing the input
477  data with a filter. The streams that will be discarded should then be freed
478  by calling deflateEnd. Note that deflateCopy duplicates the internal
479  compression state which can be quite large, so this strategy is slow and
480  can consume lots of memory.
481 
482  deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
483  enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
484  (such as zalloc being NULL). msg is left unchanged in both source and
485  destination.
486 */
487 
488 /*
489  This function is equivalent to deflateEnd followed by deflateInit,
490  but does not free and reallocate all the internal compression state.
491  The stream will keep the same compression level and any other attributes
492  that may have been set by deflateInit2.
493 
494  deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
495  stream state was inconsistent (such as zalloc or state being NULL).
496 */
497 
498 /*
499  Dynamically update the compression level and compression strategy. The
500  interpretation of level and strategy is as in deflateInit2. This can be
501  used to switch between compression and straight copy of the input data, or
502  to switch to a different kind of input data requiring a different
503  strategy. If the compression level is changed, the input available so far
504  is compressed with the old level (and may be flushed); the new level will
505  take effect only at the next call of deflate().
506 
507  Before the call of deflateParams, the stream state must be set as for
508  a call of deflate(), since the currently available input may have to
509  be compressed and flushed. In particular, strm->avail_out must be non-zero.
510 
511  deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source
512  stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR
513  if strm->avail_out was zero.
514 */
515 
516 /*
517 ZEXTERN(int) inflateInit2 OF((z_streamp strm,
518  int windowBits));
519 
520  This is another version of inflateInit with an extra parameter. The
521  fields next_in, avail_in, zalloc, zfree and opaque must be initialized
522  before by the caller.
523 
524  The windowBits parameter is the base two logarithm of the maximum window
525  size (the size of the history buffer). It should be in the range 8..15 for
526  this version of the library. The default value is 15 if inflateInit is used
527  instead. If a compressed stream with a larger window size is given as
528  input, inflate() will return with the error code Z_DATA_ERROR instead of
529  trying to allocate a larger window.
530 
531  inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
532  memory, Z_STREAM_ERROR if a parameter is invalid (such as a negative
533  memLevel). msg is set to null if there is no error message. inflateInit2
534  does not perform any decompression apart from reading the zlib header if
535  present: this will be done by inflate(). (So next_in and avail_in may be
536  modified, but next_out and avail_out are unchanged.)
537 */
538 
539 /*
540  Initializes the decompression dictionary from the given uncompressed byte
541  sequence. This function must be called immediately after a call of inflate
542  if this call returned Z_NEED_DICT. The dictionary chosen by the compressor
543  can be determined from the Adler32 value returned by this call of
544  inflate. The compressor and decompressor must use exactly the same
545  dictionary (see deflateSetDictionary).
546 
547  inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
548  parameter is invalid (such as NULL dictionary) or the stream state is
549  inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
550  expected one (incorrect Adler32 value). inflateSetDictionary does not
551  perform any decompression: this will be done by subsequent calls of
552  inflate().
553 */
554 
555 /*
556  Skips invalid compressed data until a full flush point (see above the
557  description of deflate with Z_FULL_FLUSH) can be found, or until all
558  available input is skipped. No output is provided.
559 
560  inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR
561  if no more input was provided, Z_DATA_ERROR if no flush point has been found,
562  or Z_STREAM_ERROR if the stream structure was inconsistent. In the success
563  case, the application may save the current value of total_in which
564  indicates where valid compressed data was found. In the error case, the
565  application may repeatedly call inflateSync, providing more input each time,
566  until success or end of the input data.
567 */
568 
570 /*
571  This function is equivalent to inflateEnd followed by inflateInit,
572  but does not free and reallocate all the internal decompression state.
573  The stream will keep attributes that may have been set by inflateInit2.
574 
575  inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
576  stream state was inconsistent (such as zalloc or state being NULL).
577 */
578 
579 
580  /* utility functions */
581 
582 /*
583  The following utility functions are implemented on top of the
584  basic stream-oriented functions. To simplify the interface, some
585  default options are assumed (compression level and memory usage,
586  standard memory allocation functions). The source code of these
587  utility functions can easily be modified if you need special options.
588 */
589 
590 /*
591  Compresses the source buffer into the destination buffer. sourceLen is
592  the byte length of the source buffer. Upon entry, destLen is the total
593  size of the destination buffer, which must be at least 0.1% larger than
594  sourceLen plus 12 bytes. Upon exit, destLen is the actual size of the
595  compressed buffer.
596  This function can be used to compress a whole file at once if the
597  input file is mmap'ed.
598  compress returns Z_OK if success, Z_MEM_ERROR if there was not
599  enough memory, Z_BUF_ERROR if there was not enough room in the output
600  buffer.
601 */
602 
603 /*
604  Compresses the source buffer into the destination buffer. The level
605  parameter has the same meaning as in deflateInit. sourceLen is the byte
606  length of the source buffer. Upon entry, destLen is the total size of the
607  destination buffer, which must be at least 0.1% larger than sourceLen plus
608  12 bytes. Upon exit, destLen is the actual size of the compressed buffer.
609 
610  compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
611  memory, Z_BUF_ERROR if there was not enough room in the output buffer,
612  Z_STREAM_ERROR if the level parameter is invalid.
613 */
614 
615 /*
616  Decompresses the source buffer into the destination buffer. sourceLen is
617  the byte length of the source buffer. Upon entry, destLen is the total
618  size of the destination buffer, which must be large enough to hold the
619  entire uncompressed data. (The size of the uncompressed data must have
620  been saved previously by the compressor and transmitted to the decompressor
621  by some mechanism outside the scope of this compression library.)
622  Upon exit, destLen is the actual size of the compressed buffer.
623  This function can be used to decompress a whole file at once if the
624  input file is mmap'ed.
625 
626  uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
627  enough memory, Z_BUF_ERROR if there was not enough room in the output
628  buffer, or Z_DATA_ERROR if the input data was corrupted.
629 */
630 
631 
632 /*
633  Opens a gzip (.gz) file for reading or writing. The mode parameter
634  is as in fopen ("rb" or "wb") but can also include a compression level
635  ("wb9") or a strategy: 'f' for filtered data as in "wb6f", 'h' for
636  Huffman only compression as in "wb1h". (See the description
637  of deflateInit2 for more information about the strategy parameter.)
638 
639  gzopen can be used to read a file which is not in gzip format; in this
640  case gzread will directly read from the file without decompression.
641 
642  gzopen returns NULL if the file could not be opened or if there was
643  insufficient memory to allocate the (de)compression state; errno
644  can be checked to distinguish the two cases (if errno is zero, the
645  zlib error is Z_MEM_ERROR). */
646 
647 /*
648  gzdopen() associates a gzFile with the file descriptor fd. File
649  descriptors are obtained from calls like open, dup, creat, pipe or
650  fileno (in the file has been previously opened with fopen).
651  The mode parameter is as in gzopen.
652  The next call of gzclose on the returned gzFile will also close the
653  file descriptor fd, just like fclose(fdopen(fd), mode) closes the file
654  descriptor fd. If you want to keep fd open, use gzdopen(dup(fd), mode).
655  gzdopen returns NULL if there was insufficient memory to allocate
656  the (de)compression state.
657 */
658 
659 /*
660  Dynamically update the compression level or strategy. See the description
661  of deflateInit2 for the meaning of these parameters.
662  gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not
663  opened for writing.
664 */
665 
666 /*
667  Reads the given number of uncompressed bytes from the compressed file.
668  If the input file was not in gzip format, gzread copies the given number
669  of bytes into the buffer.
670  gzread returns the number of uncompressed bytes actually read (0 for
671  end of file, -1 for error). */
672 
673 /*
674  Writes the given number of uncompressed bytes into the compressed file.
675  gzwrite returns the number of uncompressed bytes actually written
676  (0 in case of error).
677 */
678 
679 /*
680  Converts, formats, and writes the args to the compressed file under
681  control of the format string, as in fprintf. gzprintf returns the number of
682  uncompressed bytes actually written (0 in case of error).
683 */
684 
685 /*
686  Writes the given null-terminated string to the compressed file, excluding
687  the terminating null character.
688  gzputs returns the number of characters written, or -1 in case of error.
689 */
690 
691 /*
692  Reads bytes from the compressed file until len-1 characters are read, or
693  a newline character is read and transferred to buf, or an end-of-file
694  condition is encountered. The string is then terminated with a null
695  character.
696  gzgets returns buf, or Z_NULL in case of error.
697 */
698 
699 /*
700  Writes c, converted to an unsigned char, into the compressed file.
701  gzputc returns the value that was written, or -1 in case of error.
702 */
703 
704 /*
705  Reads one byte from the compressed file. gzgetc returns this byte
706  or -1 in case of end of file or error.
707 */
708 
709 /*
710  Flushes all pending output into the compressed file. The parameter
711  flush is as in the deflate() function. The return value is the zlib
712  error number (see function gzerror below). gzflush returns Z_OK if
713  the flush parameter is Z_FINISH and all output could be flushed.
714  gzflush should be called only when strictly necessary because it can
715  degrade compression.
716 */
717 
718 /*
719  Sets the starting position for the next gzread or gzwrite on the
720  given compressed file. The offset represents a number of bytes in the
721  uncompressed data stream. The whence parameter is defined as in lseek(2);
722  the value SEEK_END is not supported.
723  If the file is opened for reading, this function is emulated but can be
724  extremely slow. If the file is opened for writing, only forward seeks are
725  supported; gzseek then compresses a sequence of zeroes up to the new
726  starting position.
727 
728  gzseek returns the resulting offset location as measured in bytes from
729  the beginning of the uncompressed stream, or -1 in case of error, in
730  particular if the file is opened for writing and the new starting position
731  would be before the current position.
732 */
733 
734 /*
735  Rewinds the given file. This function is supported only for reading.
736 
737  gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET)
738 */
739 
740 /*
741  Returns the starting position for the next gzread or gzwrite on the
742  given compressed file. This position represents a number of bytes in the
743  uncompressed data stream.
744 
745  gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)
746 */
747 
748 /*
749  Returns 1 when EOF has previously been detected reading the given
750  input stream, otherwise zero.
751 */
752 
753 /*
754  Flushes all pending output if necessary, closes the compressed file
755  and deallocates all the (de)compression state. The return value is the zlib
756  error number (see function gzerror below).
757 */
758 
759 /*
760  Returns the error message for the last error which occurred on the
761  given compressed file. errnum is set to zlib error number. If an
762  error occurred in the file system and not in the compression library,
763  errnum is set to Z_ERRNO and the application may consult errno
764  to get the exact error code.
765 */
766 
767  /* checksum functions */
768 
769 /*
770  These functions are not related to compression but are exported
771  anyway because they might be useful in applications using the
772  compression library.
773 */
774 
775 ZEXTERN(uLong) adler32 OF((uLong adler, const Bytef *buf, uInt len));
776 
777 /*
778  Update a running Adler-32 checksum with the bytes buf[0..len-1] and
779  return the updated checksum. If buf is NULL, this function returns
780  the required initial value for the checksum.
781  An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
782  much faster. Usage example:
783 
784  uLong adler = adler32(0L, Z_NULL, 0);
785 
786  while (read_buffer(buffer, length) != EOF) {
787  adler = adler32(adler, buffer, length);
788  }
789  if (adler != original_adler) error();
790 */
791 
792 /*
793  Update a running crc with the bytes buf[0..len-1] and return the updated
794  crc. If buf is NULL, this function returns the required initial value
795  for the crc. Pre- and post-conditioning (one's complement) is performed
796  within this function so it shouldn't be done by the application.
797  Usage example:
798 
799  uLong crc = crc32(0L, Z_NULL, 0);
800 
801  while (read_buffer(buffer, length) != EOF) {
802  crc = crc32(crc, buffer, length);
803  }
804  if (crc != original_crc) error();
805 */
806 
807 
808  /* various hacks, don't look :) */
809 
810 /* deflateInit and inflateInit are macros to allow checking the zlib version
811  * and the compiler's view of z_stream:
812  */
814  const char *version, int stream_size));
815 #define deflateInit(strm, level) \
816  deflateInit_((strm), (level), ZLIB_VERSION, sizeof(z_stream))
817 #define inflateInit(strm) \
818  inflateInit_((strm), ZLIB_VERSION, sizeof(z_stream))
819 #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
820  deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
821  (strategy), ZLIB_VERSION, sizeof(z_stream))
822 #define inflateInit2(strm, windowBits) \
823  inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream))
824 
825 
826 #ifdef __cplusplus
827 }
828 #endif
829 
830 #endif /* _ZLIB_H */
struct png_info_def **typedef void(__cdecl typeof(png_destroy_read_struct))(struct png_struct_def **
Definition: typeof.h:49
Bytef * next_in
Definition: zlib.h:69
int windowBits
Definition: zlib.h:813
GLenum GLuint GLenum GLsizei const GLchar * buf
Definition: glext.h:7751
int ZEXPORT inflateEnd(z_streamp strm)
Definition: inflate.c:1277
uInt avail_in
Definition: zlib.h:88
voidpf alloc_func OF((voidpf opaque, uInt items, uInt size))
Definition: zlib.h:81
char * msg
Definition: zlib.h:77
Byte FAR Bytef
Definition: zconf.h:400
voidpf opaque
Definition: zlib.h:100
free_func zfree
Definition: zlib.h:99
z_stream FAR * z_streamp
Definition: zlib.h:108
int const char * version
Definition: zlib.h:813
#define FAR
Definition: guiddef.h:36
uLong reserved
Definition: zlib.h:105
int const char int stream_size
Definition: zlib.h:813
z_streamp strm
Definition: deflate.h:101
int data_type
Definition: zlib.h:102
unsigned long uLong
Definition: zconf.h:394
GLsizeiptr size
Definition: glext.h:5919
uLong total_in
Definition: zlib.h:89
alloc_func zalloc
Definition: zlib.h:98
int flush
Definition: zlib.h:309
GLuint address
Definition: glext.h:9393
int ZEXPORT inflate(z_streamp strm, int flush)
Definition: inflate.c:622
struct z_stream_s z_stream
int ZEXPORT inflateInit2_(z_streamp strm, int windowBits, const char *version, int stream_size)
Definition: inflate.c:195
int ZEXPORT inflateReset(z_streamp strm)
Definition: inflate.c:144
GLenum GLsizei len
Definition: glext.h:6722
uLong adler
Definition: zlib.h:104
ZEXTERN(int) inflate OF((z_streamp strm
uLong total_out
Definition: zlib.h:93
Byte FAR * voidpf
Definition: zconf.h:413
uInt avail_out
Definition: zlib.h:92
struct internal_state FAR * state
Definition: zlib.h:96
Bytef * next_out
Definition: zlib.h:91
static TCHAR * items[]
Definition: page1.c:45
uLong ZEXPORT adler32(uLong adler, const Bytef *buf, uInt len)
Definition: adler32.c:134
unsigned int uInt
Definition: zconf.h:393