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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 "zconf.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
89 typedef z_stream FAR *z_streamp;
90
91 /*
92 The application must update next_in and avail_in when avail_in has
93 dropped to zero. It must update next_out and avail_out when avail_out
94 has dropped to zero. The application must initialize zalloc, zfree and
95 opaque before calling the init function. All other fields are set by the
96 compression library and must not be updated by the application.
97
98 The opaque value provided by the application will be passed as the first
99 parameter for calls of zalloc and zfree. This can be useful for custom
100 memory management. The compression library attaches no meaning to the
101 opaque value.
102
103 zalloc must return Z_NULL if there is not enough memory for the object.
104 If zlib is used in a multi-threaded application, zalloc and zfree must be
105 thread safe.
106
107 On 16-bit systems, the functions zalloc and zfree must be able to allocate
108 exactly 65536 bytes, but will not be required to allocate more than this
109 if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS,
110 pointers returned by zalloc for objects of exactly 65536 bytes *must*
111 have their offset normalized to zero. The default allocation function
112 provided by this library ensures this (see zutil.c). To reduce memory
113 requirements and avoid any allocation of 64K objects, at the expense of
114 compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h).
115
116 The fields total_in and total_out can be used for statistics or
117 progress reports. After compression, total_in holds the total size of
118 the uncompressed data and may be saved for use in the decompressor
119 (particularly if the decompressor wants to decompress everything in
120 a single step).
121 */
122
123 /* constants */
124
125 #define Z_NO_FLUSH 0
126 #define Z_PARTIAL_FLUSH 1 /* will be removed, use Z_SYNC_FLUSH instead */
127 #define Z_SYNC_FLUSH 2
128 #define Z_FULL_FLUSH 3
129 #define Z_FINISH 4
130 /* Allowed flush values; see deflate() below for details */
131
132 #define Z_OK 0
133 #define Z_STREAM_END 1
134 #define Z_NEED_DICT 2
135 #define Z_ERRNO (-1)
136 #define Z_STREAM_ERROR (-2)
137 #define Z_DATA_ERROR (-3)
138 #define Z_MEM_ERROR (-4)
139 #define Z_BUF_ERROR (-5)
140 #define Z_VERSION_ERROR (-6)
141 /* Return codes for the compression/decompression functions. Negative
142 * values are errors, positive values are used for special but normal events.
143 */
144
145 #define Z_NO_COMPRESSION 0
146 #define Z_BEST_SPEED 1
147 #define Z_BEST_COMPRESSION 9
148 #define Z_DEFAULT_COMPRESSION (-1)
149 /* compression levels */
150
151 #define Z_FILTERED 1
152 #define Z_HUFFMAN_ONLY 2
153 #define Z_DEFAULT_STRATEGY 0
154 /* compression strategy; see deflateInit2() below for details */
155
156 #define Z_BINARY 0
157 #define Z_ASCII 1
158 #define Z_UNKNOWN 2
159 /* Possible values of the data_type field */
160
161 #define Z_DEFLATED 8
162 /* The deflate compression method (the only one supported in this version) */
163
164 #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */
165
166
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
309 ZEXTERN(int) inflate OF((z_streamp strm, int flush));
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
378 ZEXTERN(int) inflateEnd OF((z_streamp strm));
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 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
569 ZEXTERN(int) inflateReset OF((z_streamp strm));
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 */
813 ZEXTERN(int) inflateInit2_ OF((z_streamp strm, int windowBits,
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 */
zconf.h
uLong
unsigned long uLong
Definition: zconf.h:222
Bytef
Byte FAR Bytef
Definition: zconf.h:228
inflateEnd
int ZEXPORT inflateEnd(z_streamp strm)
Definition: inflate.c:1238
z_stream_s::avail_in
uInt avail_in
Definition: zlib.h:70
z_stream
struct z_stream_s z_stream
version
int const char * version
Definition: zlib.h:813
ZEXTERN
#define ZEXTERN(x)
Definition: zconf.h:208
voidpf
Byte FAR * voidpf
Definition: zconf.h:239
len
GLenum GLsizei len
Definition: glew.h:7035
uInt
unsigned int uInt
Definition: zconf.h:221
z_stream_s::opaque
voidpf opaque
Definition: zlib.h:82
z_stream_s::zfree
free_func zfree
Definition: zlib.h:81
stream_size
int const char int stream_size
Definition: zlib.h:813
z_stream_s::reserved
uLong reserved
Definition: zlib.h:86
z_stream_s::data_type
int data_type
Definition: zlib.h:84
z_stream_s::total_in
uLong total_in
Definition: zlib.h:71
address
GLuint GLuint64EXT address
Definition: glew.h:13266
z_stream_s::zalloc
alloc_func zalloc
Definition: zlib.h:80
FAR
#define FAR
Definition: zconf.h:215
inflate
int ZEXPORT inflate(z_streamp strm, int flush)
Definition: inflate.c:589
windowBits
int windowBits
Definition: zlib.h:813
inflateInit2_
int ZEXPORT inflateInit2_(z_streamp strm, int windowBits, const char *version, int stream_size)
Definition: inflate.c:168
inflateReset
int ZEXPORT inflateReset(z_streamp strm)
Definition: inflate.c:103
z_stream_s::next_in
Bytef * next_in
Definition: zlib.h:69
OF
#define OF(args)
Definition: zconf.h:146
z_stream_s::adler
uLong adler
Definition: zlib.h:85
z_streamp
z_stream FAR * z_streamp
Definition: zlib.h:89
z_stream_s::msg
char * msg
Definition: zlib.h:77
z_stream_s::total_out
uLong total_out
Definition: zlib.h:75
const
#define const
Definition: zconf.h:91
buf
GLenum GLuint GLsizei const GLchar * buf
Definition: glew.h:2539
flush
int flush
Definition: zlib.h:309
z_stream_s::avail_out
uInt avail_out
Definition: zlib.h:74
z_stream_s::state
struct internal_state FAR * state
Definition: zlib.h:78
z_stream_s::next_out
Bytef * next_out
Definition: zlib.h:73
adler32
uLong ZEXPORT adler32(uLong adler, const Bytef *buf, uInt len)
Definition: adler32.c:60
z_stream_s
Definition: zlib.h:68
size
GLsizei size
Definition: gl2ext.h:1467