1 /* zlib.h -- interface of the 'zlib' general purpose compression library
2 version 1.1.3, July 9th, 1998
3
4 Copyright (C) 1995-1998 Jean-loup Gailly and Mark Adler
5
6 This software is provided 'as-is', without any express or implied
7 warranty. In no event will the authors be held liable for any damages
8 arising from the use of this software.
9
10 Permission is granted to anyone to use this software for any purpose,
11 including commercial applications, and to alter it and redistribute it
12 freely, subject to the following restrictions:
13
14 1. The origin of this software must not be misrepresented; you must not
15 claim that you wrote the original software. If you use this software
16 in a product, an acknowledgment in the product documentation would be
17 appreciated but is not required.
18 2. Altered source versions must be plainly marked as such, and must not be
19 misrepresented as being the original software.
20 3. This notice may not be removed or altered from any source distribution.
21
22 Jean-loup Gailly Mark Adler
23 jloup@gzip.org madler@alumni.caltech.edu
24
25
26 The data format used by the zlib library is described by RFCs (Request for
27 Comments) 1950 to 1952 in the files ftp://ds.internic.net/rfc/rfc1950.txt
28 (zlib format), rfc1951.txt (deflate format) and rfc1952.txt (gzip format).
29 */
30
31 #ifndef _ZLIB_H
32 #define _ZLIB_H
33
34 #include <linux/zconf.h>
35
36 #ifdef __cplusplus
37 extern "C" {
38 #endif
39
40 #define ZLIB_VERSION "1.1.3"
41
42 /*
43 The 'zlib' compression library provides in-memory compression and
44 decompression functions, including integrity checks of the uncompressed
45 data. This version of the library supports only one compression method
46 (deflation) but other algorithms will be added later and will have the same
47 stream interface.
48
49 Compression can be done in a single step if the buffers are large
50 enough (for example if an input file is mmap'ed), or can be done by
51 repeated calls of the compression function. In the latter case, the
52 application must provide more input and/or consume the output
53 (providing more output space) before each call.
54
55 The library also supports reading and writing files in gzip (.gz) format
56 with an interface similar to that of stdio.
57
58 The library does not install any signal handler. The decoder checks
59 the consistency of the compressed data, so the library should never
60 crash even in case of corrupted input.
61 */
62
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 void *workspace; /* memory allocated for this stream */
81
82 int data_type; /* best guess about the data type: ascii or binary */
83 uLong adler; /* adler32 value of the uncompressed data */
84 uLong reserved; /* reserved for future use */
85 } z_stream;
86
87 typedef z_stream FAR *z_streamp;
88
89 /*
90 The application must update next_in and avail_in when avail_in has
91 dropped to zero. It must update next_out and avail_out when avail_out
92 has dropped to zero. The application must initialize zalloc, zfree and
93 opaque before calling the init function. All other fields are set by the
94 compression library and must not be updated by the application.
95
96 The opaque value provided by the application will be passed as the first
97 parameter for calls of zalloc and zfree. This can be useful for custom
98 memory management. The compression library attaches no meaning to the
99 opaque value.
100
101 zalloc must return Z_NULL if there is not enough memory for the object.
102 If zlib is used in a multi-threaded application, zalloc and zfree must be
103 thread safe.
104
105 On 16-bit systems, the functions zalloc and zfree must be able to allocate
106 exactly 65536 bytes, but will not be required to allocate more than this
107 if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS,
108 pointers returned by zalloc for objects of exactly 65536 bytes *must*
109 have their offset normalized to zero. The default allocation function
110 provided by this library ensures this (see zutil.c). To reduce memory
111 requirements and avoid any allocation of 64K objects, at the expense of
112 compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h).
113
114 The fields total_in and total_out can be used for statistics or
115 progress reports. After compression, total_in holds the total size of
116 the uncompressed data and may be saved for use in the decompressor
117 (particularly if the decompressor wants to decompress everything in
118 a single step).
119 */
120
121 /* constants */
122
123 #define Z_NO_FLUSH 0
124 #define Z_PARTIAL_FLUSH 1 /* will be removed, use Z_SYNC_FLUSH instead */
125 #define Z_PACKET_FLUSH 2
126 #define Z_SYNC_FLUSH 3
127 #define Z_FULL_FLUSH 4
128 #define Z_FINISH 5
129 /* Allowed flush values; see deflate() below for details */
130
131 #define Z_OK 0
132 #define Z_STREAM_END 1
133 #define Z_NEED_DICT 2
134 #define Z_ERRNO (-1)
135 #define Z_STREAM_ERROR (-2)
136 #define Z_DATA_ERROR (-3)
137 #define Z_MEM_ERROR (-4)
138 #define Z_BUF_ERROR (-5)
139 #define Z_VERSION_ERROR (-6)
140 /* Return codes for the compression/decompression functions. Negative
141 * values are errors, positive values are used for special but normal events.
142 */
143
144 #define Z_NO_COMPRESSION 0
145 #define Z_BEST_SPEED 1
146 #define Z_BEST_COMPRESSION 9
147 #define Z_DEFAULT_COMPRESSION (-1)
148 /* compression levels */
149
150 #define Z_FILTERED 1
151 #define Z_HUFFMAN_ONLY 2
152 #define Z_DEFAULT_STRATEGY 0
153 /* compression strategy; see deflateInit2() below for details */
154
155 #define Z_BINARY 0
156 #define Z_ASCII 1
157 #define Z_UNKNOWN 2
158 /* Possible values of the data_type field */
159
160 #define Z_DEFLATED 8
161 /* The deflate compression method (the only one supported in this version) */
162
163 #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */
164
165 /* basic functions */
166
167 ZEXTERN const char * ZEXPORT zlib_zlibVersion OF((void));
168 /* The application can compare zlibVersion and ZLIB_VERSION for consistency.
169 If the first character differs, the library code actually used is
170 not compatible with the zlib.h header file used by the application.
171 This check is automatically made by deflateInit and inflateInit.
172 */
173
174 ZEXTERN int ZEXPORT zlib_deflate_workspacesize OF((void));
175 /*
176 Returns the number of bytes that needs to be allocated for a per-
177 stream workspace. A pointer to this number of bytes should be
178 returned in stream->workspace before calling zlib_deflateInit().
179 */
180
181 /*
182 ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level));
183
184 Initializes the internal stream state for compression. The fields
185 zalloc, zfree and opaque must be initialized before by the caller.
186 If zalloc and zfree are set to Z_NULL, deflateInit updates them to
187 use default allocation functions.
188
189 The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
190 1 gives best speed, 9 gives best compression, 0 gives no compression at
191 all (the input data is simply copied a block at a time).
192 Z_DEFAULT_COMPRESSION requests a default compromise between speed and
193 compression (currently equivalent to level 6).
194
195 deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not
196 enough memory, Z_STREAM_ERROR if level is not a valid compression level,
197 Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
198 with the version assumed by the caller (ZLIB_VERSION).
199 msg is set to null if there is no error message. deflateInit does not
200 perform any compression: this will be done by deflate().
201 */
202
203
204 ZEXTERN int ZEXPORT zlib_deflate OF((z_streamp strm, int flush));
205 /*
206 deflate compresses as much data as possible, and stops when the input
207 buffer becomes empty or the output buffer becomes full. It may introduce some
208 output latency (reading input without producing any output) except when
209 forced to flush.
210
211 The detailed semantics are as follows. deflate performs one or both of the
212 following actions:
213
214 - Compress more input starting at next_in and update next_in and avail_in
215 accordingly. If not all input can be processed (because there is not
216 enough room in the output buffer), next_in and avail_in are updated and
217 processing will resume at this point for the next call of deflate().
218
219 - Provide more output starting at next_out and update next_out and avail_out
220 accordingly. This action is forced if the parameter flush is non zero.
221 Forcing flush frequently degrades the compression ratio, so this parameter
222 should be set only when necessary (in interactive applications).
223 Some output may be provided even if flush is not set.
224
225 Before the call of deflate(), the application should ensure that at least
226 one of the actions is possible, by providing more input and/or consuming
227 more output, and updating avail_in or avail_out accordingly; avail_out
228 should never be zero before the call. The application can consume the
229 compressed output when it wants, for example when the output buffer is full
230 (avail_out == 0), or after each call of deflate(). If deflate returns Z_OK
231 and with zero avail_out, it must be called again after making room in the
232 output buffer because there might be more output pending.
233
234 If the parameter flush is set to Z_SYNC_FLUSH, all pending output is
235 flushed to the output buffer and the output is aligned on a byte boundary, so
236 that the decompressor can get all input data available so far. (In particular
237 avail_in is zero after the call if enough output space has been provided
238 before the call.) Flushing may degrade compression for some compression
239 algorithms and so it should be used only when necessary.
240
241 If flush is set to Z_FULL_FLUSH, all output is flushed as with
242 Z_SYNC_FLUSH, and the compression state is reset so that decompression can
243 restart from this point if previous compressed data has been damaged or if
244 random access is desired. Using Z_FULL_FLUSH too often can seriously degrade
245 the compression.
246
247 If deflate returns with avail_out == 0, this function must be called again
248 with the same value of the flush parameter and more output space (updated
249 avail_out), until the flush is complete (deflate returns with non-zero
250 avail_out).
251
252 If the parameter flush is set to Z_FINISH, pending input is processed,
253 pending output is flushed and deflate returns with Z_STREAM_END if there
254 was enough output space; if deflate returns with Z_OK, this function must be
255 called again with Z_FINISH and more output space (updated avail_out) but no
256 more input data, until it returns with Z_STREAM_END or an error. After
257 deflate has returned Z_STREAM_END, the only possible operations on the
258 stream are deflateReset or deflateEnd.
259
260 Z_FINISH can be used immediately after deflateInit if all the compression
261 is to be done in a single step. In this case, avail_out must be at least
262 0.1% larger than avail_in plus 12 bytes. If deflate does not return
263 Z_STREAM_END, then it must be called again as described above.
264
265 deflate() sets strm->adler to the adler32 checksum of all input read
266 so far (that is, total_in bytes).
267
268 deflate() may update data_type if it can make a good guess about
269 the input data type (Z_ASCII or Z_BINARY). In doubt, the data is considered
270 binary. This field is only for information purposes and does not affect
271 the compression algorithm in any manner.
272
273 deflate() returns Z_OK if some progress has been made (more input
274 processed or more output produced), Z_STREAM_END if all input has been
275 consumed and all output has been produced (only when flush is set to
276 Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
277 if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible
278 (for example avail_in or avail_out was zero).
279 */
280
281
282 ZEXTERN int ZEXPORT zlib_deflateEnd OF((z_streamp strm));
283 /*
284 All dynamically allocated data structures for this stream are freed.
285 This function discards any unprocessed input and does not flush any
286 pending output.
287
288 deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
289 stream state was inconsistent, Z_DATA_ERROR if the stream was freed
290 prematurely (some input or output was discarded). In the error case,
291 msg may be set but then points to a static string (which must not be
292 deallocated).
293 */
294
295
296 ZEXTERN int ZEXPORT zlib_inflate_workspacesize OF((void));
297 /*
298 Returns the number of bytes that needs to be allocated for a per-
299 stream workspace. A pointer to this number of bytes should be
300 returned in stream->workspace before calling zlib_inflateInit().
301 */
302
303 /*
304 ZEXTERN int ZEXPORT zlib_inflateInit OF((z_streamp strm));
305
306 Initializes the internal stream state for decompression. The fields
307 next_in, avail_in, and workspace must be initialized before by
308 the caller. If next_in is not Z_NULL and avail_in is large enough (the exact
309 value depends on the compression method), inflateInit determines the
310 compression method from the zlib header and allocates all data structures
311 accordingly; otherwise the allocation will be deferred to the first call of
312 inflate. If zalloc and zfree are set to Z_NULL, inflateInit updates them to
313 use default allocation functions.
314
315 inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
316 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
317 version assumed by the caller. msg is set to null if there is no error
318 message. inflateInit does not perform any decompression apart from reading
319 the zlib header if present: this will be done by inflate(). (So next_in and
320 avail_in may be modified, but next_out and avail_out are unchanged.)
321 */
322
323
324 ZEXTERN int ZEXPORT zlib_inflate OF((z_streamp strm, int flush));
325 /*
326 inflate decompresses as much data as possible, and stops when the input
327 buffer becomes empty or the output buffer becomes full. It may some
328 introduce some output latency (reading input without producing any output)
329 except when forced to flush.
330
331 The detailed semantics are as follows. inflate performs one or both of the
332 following actions:
333
334 - Decompress more input starting at next_in and update next_in and avail_in
335 accordingly. If not all input can be processed (because there is not
336 enough room in the output buffer), next_in is updated and processing
337 will resume at this point for the next call of inflate().
338
339 - Provide more output starting at next_out and update next_out and avail_out
340 accordingly. inflate() provides as much output as possible, until there
341 is no more input data or no more space in the output buffer (see below
342 about the flush parameter).
343
344 Before the call of inflate(), the application should ensure that at least
345 one of the actions is possible, by providing more input and/or consuming
346 more output, and updating the next_* and avail_* values accordingly.
347 The application can consume the uncompressed output when it wants, for
348 example when the output buffer is full (avail_out == 0), or after each
349 call of inflate(). If inflate returns Z_OK and with zero avail_out, it
350 must be called again after making room in the output buffer because there
351 might be more output pending.
352
353 If the parameter flush is set to Z_SYNC_FLUSH, inflate flushes as much
354 output as possible to the output buffer. The flushing behavior of inflate is
355 not specified for values of the flush parameter other than Z_SYNC_FLUSH
356 and Z_FINISH, but the current implementation actually flushes as much output
357 as possible anyway.
358
359 inflate() should normally be called until it returns Z_STREAM_END or an
360 error. However if all decompression is to be performed in a single step
361 (a single call of inflate), the parameter flush should be set to
362 Z_FINISH. In this case all pending input is processed and all pending
363 output is flushed; avail_out must be large enough to hold all the
364 uncompressed data. (The size of the uncompressed data may have been saved
365 by the compressor for this purpose.) The next operation on this stream must
366 be inflateEnd to deallocate the decompression state. The use of Z_FINISH
367 is never required, but can be used to inform inflate that a faster routine
368 may be used for the single inflate() call.
369
370 If a preset dictionary is needed at this point (see inflateSetDictionary
371 below), inflate sets strm-adler to the adler32 checksum of the
372 dictionary chosen by the compressor and returns Z_NEED_DICT; otherwise
373 it sets strm->adler to the adler32 checksum of all output produced
374 so far (that is, total_out bytes) and returns Z_OK, Z_STREAM_END or
375 an error code as described below. At the end of the stream, inflate()
376 checks that its computed adler32 checksum is equal to that saved by the
377 compressor and returns Z_STREAM_END only if the checksum is correct.
378
379 inflate() returns Z_OK if some progress has been made (more input processed
380 or more output produced), Z_STREAM_END if the end of the compressed data has
381 been reached and all uncompressed output has been produced, Z_NEED_DICT if a
382 preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
383 corrupted (input stream not conforming to the zlib format or incorrect
384 adler32 checksum), Z_STREAM_ERROR if the stream structure was inconsistent
385 (for example if next_in or next_out was NULL), Z_MEM_ERROR if there was not
386 enough memory, Z_BUF_ERROR if no progress is possible or if there was not
387 enough room in the output buffer when Z_FINISH is used. In the Z_DATA_ERROR
388 case, the application may then call inflateSync to look for a good
389 compression block.
390 */
391
392
393 ZEXTERN int ZEXPORT zlib_inflateEnd OF((z_streamp strm));
394 /*
395 All dynamically allocated data structures for this stream are freed.
396 This function discards any unprocessed input and does not flush any
397 pending output.
398
399 inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state
400 was inconsistent. In the error case, msg may be set but then points to a
401 static string (which must not be deallocated).
402 */
403
404 /* Advanced functions */
405
406 /*
407 The following functions are needed only in some special applications.
408 */
409
410 /*
411 ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm,
412 int level,
413 int method,
414 int windowBits,
415 int memLevel,
416 int strategy));
417
418 This is another version of deflateInit with more compression options. The
419 fields next_in, zalloc, zfree and opaque must be initialized before by
420 the caller.
421
422 The method parameter is the compression method. It must be Z_DEFLATED in
423 this version of the library.
424
425 The windowBits parameter is the base two logarithm of the window size
426 (the size of the history buffer). It should be in the range 8..15 for this
427 version of the library. Larger values of this parameter result in better
428 compression at the expense of memory usage. The default value is 15 if
429 deflateInit is used instead.
430
431 The memLevel parameter specifies how much memory should be allocated
432 for the internal compression state. memLevel=1 uses minimum memory but
433 is slow and reduces compression ratio; memLevel=9 uses maximum memory
434 for optimal speed. The default value is 8. See zconf.h for total memory
435 usage as a function of windowBits and memLevel.
436
437 The strategy parameter is used to tune the compression algorithm. Use the
438 value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
439 filter (or predictor), or Z_HUFFMAN_ONLY to force Huffman encoding only (no
440 string match). Filtered data consists mostly of small values with a
441 somewhat random distribution. In this case, the compression algorithm is
442 tuned to compress them better. The effect of Z_FILTERED is to force more
443 Huffman coding and less string matching; it is somewhat intermediate
444 between Z_DEFAULT and Z_HUFFMAN_ONLY. The strategy parameter only affects
445 the compression ratio but not the correctness of the compressed output even
446 if it is not set appropriately.
447
448 deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
449 memory, Z_STREAM_ERROR if a parameter is invalid (such as an invalid
450 method). msg is set to null if there is no error message. deflateInit2 does
451 not perform any compression: this will be done by deflate().
452 */
453
454 ZEXTERN int ZEXPORT zlib_deflateSetDictionary OF((z_streamp strm,
455 const Bytef *dictionary,
456 uInt dictLength));
457 /*
458 Initializes the compression dictionary from the given byte sequence
459 without producing any compressed output. This function must be called
460 immediately after deflateInit, deflateInit2 or deflateReset, before any
461 call of deflate. The compressor and decompressor must use exactly the same
462 dictionary (see inflateSetDictionary).
463
464 The dictionary should consist of strings (byte sequences) that are likely
465 to be encountered later in the data to be compressed, with the most commonly
466 used strings preferably put towards the end of the dictionary. Using a
467 dictionary is most useful when the data to be compressed is short and can be
468 predicted with good accuracy; the data can then be compressed better than
469 with the default empty dictionary.
470
471 Depending on the size of the compression data structures selected by
472 deflateInit or deflateInit2, a part of the dictionary may in effect be
473 discarded, for example if the dictionary is larger than the window size in
474 deflate or deflate2. Thus the strings most likely to be useful should be
475 put at the end of the dictionary, not at the front.
476
477 Upon return of this function, strm->adler is set to the Adler32 value
478 of the dictionary; the decompressor may later use this value to determine
479 which dictionary has been used by the compressor. (The Adler32 value
480 applies to the whole dictionary even if only a subset of the dictionary is
481 actually used by the compressor.)
482
483 deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
484 parameter is invalid (such as NULL dictionary) or the stream state is
485 inconsistent (for example if deflate has already been called for this stream
486 or if the compression method is bsort). deflateSetDictionary does not
487 perform any compression: this will be done by deflate().
488 */
489
490 ZEXTERN int ZEXPORT zlib_deflateCopy OF((z_streamp dest,
491 z_streamp source));
492 /*
493 Sets the destination stream as a complete copy of the source stream.
494
495 This function can be useful when several compression strategies will be
496 tried, for example when there are several ways of pre-processing the input
497 data with a filter. The streams that will be discarded should then be freed
498 by calling deflateEnd. Note that deflateCopy duplicates the internal
499 compression state which can be quite large, so this strategy is slow and
500 can consume lots of memory.
501
502 deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
503 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
504 (such as zalloc being NULL). msg is left unchanged in both source and
505 destination.
506 */
507
508 ZEXTERN int ZEXPORT zlib_deflateReset OF((z_streamp strm));
509 /*
510 This function is equivalent to deflateEnd followed by deflateInit,
511 but does not free and reallocate all the internal compression state.
512 The stream will keep the same compression level and any other attributes
513 that may have been set by deflateInit2.
514
515 deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
516 stream state was inconsistent (such as zalloc or state being NULL).
517 */
518
deflateBound(unsigned long s)519 static inline unsigned long deflateBound(unsigned long s)
520 {
521 return s + ((s + 7) >> 3) + ((s + 63) >> 6) + 11;
522 }
523
524 ZEXTERN int ZEXPORT zlib_deflateParams OF((z_streamp strm,
525 int level,
526 int strategy));
527 /*
528 Dynamically update the compression level and compression strategy. The
529 interpretation of level and strategy is as in deflateInit2. This can be
530 used to switch between compression and straight copy of the input data, or
531 to switch to a different kind of input data requiring a different
532 strategy. If the compression level is changed, the input available so far
533 is compressed with the old level (and may be flushed); the new level will
534 take effect only at the next call of deflate().
535
536 Before the call of deflateParams, the stream state must be set as for
537 a call of deflate(), since the currently available input may have to
538 be compressed and flushed. In particular, strm->avail_out must be non-zero.
539
540 deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source
541 stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR
542 if strm->avail_out was zero.
543 */
544
545 /*
546 ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm,
547 int windowBits));
548
549 This is another version of inflateInit with an extra parameter. The
550 fields next_in, avail_in, zalloc, zfree and opaque must be initialized
551 before by the caller.
552
553 The windowBits parameter is the base two logarithm of the maximum window
554 size (the size of the history buffer). It should be in the range 8..15 for
555 this version of the library. The default value is 15 if inflateInit is used
556 instead. If a compressed stream with a larger window size is given as
557 input, inflate() will return with the error code Z_DATA_ERROR instead of
558 trying to allocate a larger window.
559
560 inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
561 memory, Z_STREAM_ERROR if a parameter is invalid (such as a negative
562 memLevel). msg is set to null if there is no error message. inflateInit2
563 does not perform any decompression apart from reading the zlib header if
564 present: this will be done by inflate(). (So next_in and avail_in may be
565 modified, but next_out and avail_out are unchanged.)
566 */
567
568 ZEXTERN int ZEXPORT zlib_inflateSetDictionary OF((z_streamp strm,
569 const Bytef *dictionary,
570 uInt dictLength));
571 /*
572 Initializes the decompression dictionary from the given uncompressed byte
573 sequence. This function must be called immediately after a call of inflate
574 if this call returned Z_NEED_DICT. The dictionary chosen by the compressor
575 can be determined from the Adler32 value returned by this call of
576 inflate. The compressor and decompressor must use exactly the same
577 dictionary (see deflateSetDictionary).
578
579 inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
580 parameter is invalid (such as NULL dictionary) or the stream state is
581 inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
582 expected one (incorrect Adler32 value). inflateSetDictionary does not
583 perform any decompression: this will be done by subsequent calls of
584 inflate().
585 */
586
587 ZEXTERN int ZEXPORT zlib_inflateSync OF((z_streamp strm));
588 /*
589 Skips invalid compressed data until a full flush point (see above the
590 description of deflate with Z_FULL_FLUSH) can be found, or until all
591 available input is skipped. No output is provided.
592
593 inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR
594 if no more input was provided, Z_DATA_ERROR if no flush point has been found,
595 or Z_STREAM_ERROR if the stream structure was inconsistent. In the success
596 case, the application may save the current current value of total_in which
597 indicates where valid compressed data was found. In the error case, the
598 application may repeatedly call inflateSync, providing more input each time,
599 until success or end of the input data.
600 */
601
602 ZEXTERN int ZEXPORT zlib_inflateReset OF((z_streamp strm));
603 /*
604 This function is equivalent to inflateEnd followed by inflateInit,
605 but does not free and reallocate all the internal decompression state.
606 The stream will keep attributes that may have been set by inflateInit2.
607
608 inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
609 stream state was inconsistent (such as zalloc or state being NULL).
610 */
611
612 extern int ZEXPORT zlib_inflateIncomp OF((z_stream *strm));
613 /*
614 This function adds the data at next_in (avail_in bytes) to the output
615 history without performing any output. There must be no pending output,
616 and the decompressor must be expecting to see the start of a block.
617 Calling this function is equivalent to decompressing a stored block
618 containing the data at next_in (except that the data is not output).
619 */
620
621 /* various hacks, don't look :) */
622
623 /* deflateInit and inflateInit are macros to allow checking the zlib version
624 * and the compiler's view of z_stream:
625 */
626 ZEXTERN int ZEXPORT zlib_deflateInit_ OF((z_streamp strm, int level,
627 const char *version, int stream_size));
628 ZEXTERN int ZEXPORT zlib_inflateInit_ OF((z_streamp strm,
629 const char *version, int stream_size));
630 ZEXTERN int ZEXPORT zlib_deflateInit2_ OF((z_streamp strm, int level, int method,
631 int windowBits, int memLevel,
632 int strategy, const char *version,
633 int stream_size));
634 ZEXTERN int ZEXPORT zlib_inflateInit2_ OF((z_streamp strm, int windowBits,
635 const char *version, int stream_size));
636 #define zlib_deflateInit(strm, level) \
637 zlib_deflateInit_((strm), (level), ZLIB_VERSION, sizeof(z_stream))
638 #define zlib_inflateInit(strm) \
639 zlib_inflateInit_((strm), ZLIB_VERSION, sizeof(z_stream))
640 #define zlib_deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
641 zlib_deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
642 (strategy), ZLIB_VERSION, sizeof(z_stream))
643 #define zlib_inflateInit2(strm, windowBits) \
644 zlib_inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream))
645
646
647 #if !defined(_Z_UTIL_H) && !defined(NO_DUMMY_DECL)
648 struct internal_state {int dummy;}; /* hack for buggy compilers */
649 #endif
650
651 ZEXTERN const char * ZEXPORT zlib_zError OF((int err));
652 ZEXTERN int ZEXPORT zlib_inflateSyncPoint OF((z_streamp z));
653 ZEXTERN const uLongf * ZEXPORT zlib_get_crc_table OF((void));
654
655 #ifdef __cplusplus
656 }
657 #endif
658
659 #endif /* _ZLIB_H */
660