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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/* 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#define ZLIB_VERSION "1.1.3"
37
38/*
39 The 'zlib' compression library provides in-memory compression and
40 decompression functions, including integrity checks of the uncompressed
41 data. This version of the library supports only one compression method
42 (deflation) but other algorithms will be added later and will have the same
43 stream interface.
44
45 Compression can be done in a single step if the buffers are large
46 enough (for example if an input file is mmap'ed), or can be done by
47 repeated calls of the compression function. In the latter case, the
48 application must provide more input and/or consume the output
49 (providing more output space) before each call.
50
51 The library also supports reading and writing files in gzip (.gz) format
52 with an interface similar to that of stdio.
53
54 The library does not install any signal handler. The decoder checks
55 the consistency of the compressed data, so the library should never
56 crash even in case of corrupted input.
57*/
58
59struct internal_state;
60
61typedef struct z_stream_s {
62 Byte *next_in; /* next input byte */
63 uInt avail_in; /* number of bytes available at next_in */
64 uLong total_in; /* total nb of input bytes read so far */
65
66 Byte *next_out; /* next output byte should be put there */
67 uInt avail_out; /* remaining free space at next_out */
68 uLong total_out; /* total nb of bytes output so far */
69
70 char *msg; /* last error message, NULL if no error */
71 struct internal_state *state; /* not visible by applications */
72
73 void *workspace; /* memory allocated for this stream */
74
75 int data_type; /* best guess about the data type: ascii or binary */
76 uLong adler; /* adler32 value of the uncompressed data */
77 uLong reserved; /* reserved for future use */
78} z_stream;
79
80typedef z_stream *z_streamp;
81
82/*
83 The application must update next_in and avail_in when avail_in has
84 dropped to zero. It must update next_out and avail_out when avail_out
85 has dropped to zero. The application must initialize zalloc, zfree and
86 opaque before calling the init function. All other fields are set by the
87 compression library and must not be updated by the application.
88
89 The opaque value provided by the application will be passed as the first
90 parameter for calls of zalloc and zfree. This can be useful for custom
91 memory management. The compression library attaches no meaning to the
92 opaque value.
93
94 zalloc must return NULL if there is not enough memory for the object.
95 If zlib is used in a multi-threaded application, zalloc and zfree must be
96 thread safe.
97
98 On 16-bit systems, the functions zalloc and zfree must be able to allocate
99 exactly 65536 bytes, but will not be required to allocate more than this
100 if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS,
101 pointers returned by zalloc for objects of exactly 65536 bytes *must*
102 have their offset normalized to zero. The default allocation function
103 provided by this library ensures this (see zutil.c). To reduce memory
104 requirements and avoid any allocation of 64K objects, at the expense of
105 compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h).
106
107 The fields total_in and total_out can be used for statistics or
108 progress reports. After compression, total_in holds the total size of
109 the uncompressed data and may be saved for use in the decompressor
110 (particularly if the decompressor wants to decompress everything in
111 a single step).
112*/
113
114 /* constants */
115
116#define Z_NO_FLUSH 0
117#define Z_PARTIAL_FLUSH 1 /* will be removed, use Z_SYNC_FLUSH instead */
118#define Z_PACKET_FLUSH 2
119#define Z_SYNC_FLUSH 3
120#define Z_FULL_FLUSH 4
121#define Z_FINISH 5
122/* Allowed flush values; see deflate() below for details */
123
124#define Z_OK 0
125#define Z_STREAM_END 1
126#define Z_NEED_DICT 2
127#define Z_ERRNO (-1)
128#define Z_STREAM_ERROR (-2)
129#define Z_DATA_ERROR (-3)
130#define Z_MEM_ERROR (-4)
131#define Z_BUF_ERROR (-5)
132#define Z_VERSION_ERROR (-6)
133/* Return codes for the compression/decompression functions. Negative
134 * values are errors, positive values are used for special but normal events.
135 */
136
137#define Z_NO_COMPRESSION 0
138#define Z_BEST_SPEED 1
139#define Z_BEST_COMPRESSION 9
140#define Z_DEFAULT_COMPRESSION (-1)
141/* compression levels */
142
143#define Z_FILTERED 1
144#define Z_HUFFMAN_ONLY 2
145#define Z_DEFAULT_STRATEGY 0
146/* compression strategy; see deflateInit2() below for details */
147
148#define Z_BINARY 0
149#define Z_ASCII 1
150#define Z_UNKNOWN 2
151/* Possible values of the data_type field */
152
153#define Z_DEFLATED 8
154/* The deflate compression method (the only one supported in this version) */
155
156 /* basic functions */
157
158extern const char * zlib_zlibVersion (void);
159/* The application can compare zlibVersion and ZLIB_VERSION for consistency.
160 If the first character differs, the library code actually used is
161 not compatible with the zlib.h header file used by the application.
162 This check is automatically made by deflateInit and inflateInit.
163 */
164
165extern int zlib_deflate_workspacesize (void);
166/*
167 Returns the number of bytes that needs to be allocated for a per-
168 stream workspace. A pointer to this number of bytes should be
169 returned in stream->workspace before calling zlib_deflateInit().
170*/
171
172/*
173extern int deflateInit (z_streamp strm, int level);
174
175 Initializes the internal stream state for compression. The fields
176 zalloc, zfree and opaque must be initialized before by the caller.
177 If zalloc and zfree are set to NULL, deflateInit updates them to
178 use default allocation functions.
179
180 The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
181 1 gives best speed, 9 gives best compression, 0 gives no compression at
182 all (the input data is simply copied a block at a time).
183 Z_DEFAULT_COMPRESSION requests a default compromise between speed and
184 compression (currently equivalent to level 6).
185
186 deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not
187 enough memory, Z_STREAM_ERROR if level is not a valid compression level,
188 Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
189 with the version assumed by the caller (ZLIB_VERSION).
190 msg is set to null if there is no error message. deflateInit does not
191 perform any compression: this will be done by deflate().
192*/
193
194
195extern int zlib_deflate (z_streamp strm, int flush);
196/*
197 deflate compresses as much data as possible, and stops when the input
198 buffer becomes empty or the output buffer becomes full. It may introduce some
199 output latency (reading input without producing any output) except when
200 forced to flush.
201
202 The detailed semantics are as follows. deflate performs one or both of the
203 following actions:
204
205 - Compress more input starting at next_in and update next_in and avail_in
206 accordingly. If not all input can be processed (because there is not
207 enough room in the output buffer), next_in and avail_in are updated and
208 processing will resume at this point for the next call of deflate().
209
210 - Provide more output starting at next_out and update next_out and avail_out
211 accordingly. This action is forced if the parameter flush is non zero.
212 Forcing flush frequently degrades the compression ratio, so this parameter
213 should be set only when necessary (in interactive applications).
214 Some output may be provided even if flush is not set.
215
216 Before the call of deflate(), the application should ensure that at least
217 one of the actions is possible, by providing more input and/or consuming
218 more output, and updating avail_in or avail_out accordingly; avail_out
219 should never be zero before the call. The application can consume the
220 compressed output when it wants, for example when the output buffer is full
221 (avail_out == 0), or after each call of deflate(). If deflate returns Z_OK
222 and with zero avail_out, it must be called again after making room in the
223 output buffer because there might be more output pending.
224
225 If the parameter flush is set to Z_SYNC_FLUSH, all pending output is
226 flushed to the output buffer and the output is aligned on a byte boundary, so
227 that the decompressor can get all input data available so far. (In particular
228 avail_in is zero after the call if enough output space has been provided
229 before the call.) Flushing may degrade compression for some compression
230 algorithms and so it should be used only when necessary.
231
232 If flush is set to Z_FULL_FLUSH, all output is flushed as with
233 Z_SYNC_FLUSH, and the compression state is reset so that decompression can
234 restart from this point if previous compressed data has been damaged or if
235 random access is desired. Using Z_FULL_FLUSH too often can seriously degrade
236 the compression.
237
238 If deflate returns with avail_out == 0, this function must be called again
239 with the same value of the flush parameter and more output space (updated
240 avail_out), until the flush is complete (deflate returns with non-zero
241 avail_out).
242
243 If the parameter flush is set to Z_FINISH, pending input is processed,
244 pending output is flushed and deflate returns with Z_STREAM_END if there
245 was enough output space; if deflate returns with Z_OK, this function must be
246 called again with Z_FINISH and more output space (updated avail_out) but no
247 more input data, until it returns with Z_STREAM_END or an error. After
248 deflate has returned Z_STREAM_END, the only possible operations on the
249 stream are deflateReset or deflateEnd.
250
251 Z_FINISH can be used immediately after deflateInit if all the compression
252 is to be done in a single step. In this case, avail_out must be at least
253 0.1% larger than avail_in plus 12 bytes. If deflate does not return
254 Z_STREAM_END, then it must be called again as described above.
255
256 deflate() sets strm->adler to the adler32 checksum of all input read
257 so far (that is, total_in bytes).
258
259 deflate() may update data_type if it can make a good guess about
260 the input data type (Z_ASCII or Z_BINARY). In doubt, the data is considered
261 binary. This field is only for information purposes and does not affect
262 the compression algorithm in any manner.
263
264 deflate() returns Z_OK if some progress has been made (more input
265 processed or more output produced), Z_STREAM_END if all input has been
266 consumed and all output has been produced (only when flush is set to
267 Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
268 if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible
269 (for example avail_in or avail_out was zero).
270*/
271
272
273extern int zlib_deflateEnd (z_streamp strm);
274/*
275 All dynamically allocated data structures for this stream are freed.
276 This function discards any unprocessed input and does not flush any
277 pending output.
278
279 deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
280 stream state was inconsistent, Z_DATA_ERROR if the stream was freed
281 prematurely (some input or output was discarded). In the error case,
282 msg may be set but then points to a static string (which must not be
283 deallocated).
284*/
285
286
287extern int zlib_inflate_workspacesize (void);
288/*
289 Returns the number of bytes that needs to be allocated for a per-
290 stream workspace. A pointer to this number of bytes should be
291 returned in stream->workspace before calling zlib_inflateInit().
292*/
293
294/*
295extern int zlib_inflateInit (z_streamp strm);
296
297 Initializes the internal stream state for decompression. The fields
298 next_in, avail_in, and workspace must be initialized before by
299 the caller. If next_in is not NULL and avail_in is large enough (the exact
300 value depends on the compression method), inflateInit determines the
301 compression method from the zlib header and allocates all data structures
302 accordingly; otherwise the allocation will be deferred to the first call of
303 inflate. If zalloc and zfree are set to NULL, inflateInit updates them to
304 use default allocation functions.
305
306 inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
307 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
308 version assumed by the caller. msg is set to null if there is no error
309 message. inflateInit does not perform any decompression apart from reading
310 the zlib header if present: this will be done by inflate(). (So next_in and
311 avail_in may be modified, but next_out and avail_out are unchanged.)
312*/
313
314
315extern int zlib_inflate (z_streamp strm, int flush);
316/*
317 inflate decompresses as much data as possible, and stops when the input
318 buffer becomes empty or the output buffer becomes full. It may some
319 introduce some output latency (reading input without producing any output)
320 except when forced to flush.
321
322 The detailed semantics are as follows. inflate performs one or both of the
323 following actions:
324
325 - Decompress more input starting at next_in and update next_in and avail_in
326 accordingly. If not all input can be processed (because there is not
327 enough room in the output buffer), next_in is updated and processing
328 will resume at this point for the next call of inflate().
329
330 - Provide more output starting at next_out and update next_out and avail_out
331 accordingly. inflate() provides as much output as possible, until there
332 is no more input data or no more space in the output buffer (see below
333 about the flush parameter).
334
335 Before the call of inflate(), the application should ensure that at least
336 one of the actions is possible, by providing more input and/or consuming
337 more output, and updating the next_* and avail_* values accordingly.
338 The application can consume the uncompressed output when it wants, for
339 example when the output buffer is full (avail_out == 0), or after each
340 call of inflate(). If inflate returns Z_OK and with zero avail_out, it
341 must be called again after making room in the output buffer because there
342 might be more output pending.
343
344 If the parameter flush is set to Z_SYNC_FLUSH, inflate flushes as much
345 output as possible to the output buffer. The flushing behavior of inflate is
346 not specified for values of the flush parameter other than Z_SYNC_FLUSH
347 and Z_FINISH, but the current implementation actually flushes as much output
348 as possible anyway.
349
350 inflate() should normally be called until it returns Z_STREAM_END or an
351 error. However if all decompression is to be performed in a single step
352 (a single call of inflate), the parameter flush should be set to
353 Z_FINISH. In this case all pending input is processed and all pending
354 output is flushed; avail_out must be large enough to hold all the
355 uncompressed data. (The size of the uncompressed data may have been saved
356 by the compressor for this purpose.) The next operation on this stream must
357 be inflateEnd to deallocate the decompression state. The use of Z_FINISH
358 is never required, but can be used to inform inflate that a faster routine
359 may be used for the single inflate() call.
360
361 If a preset dictionary is needed at this point (see inflateSetDictionary
362 below), inflate sets strm-adler to the adler32 checksum of the
363 dictionary chosen by the compressor and returns Z_NEED_DICT; otherwise
364 it sets strm->adler to the adler32 checksum of all output produced
365 so far (that is, total_out bytes) and returns Z_OK, Z_STREAM_END or
366 an error code as described below. At the end of the stream, inflate()
367 checks that its computed adler32 checksum is equal to that saved by the
368 compressor and returns Z_STREAM_END only if the checksum is correct.
369
370 inflate() returns Z_OK if some progress has been made (more input processed
371 or more output produced), Z_STREAM_END if the end of the compressed data has
372 been reached and all uncompressed output has been produced, Z_NEED_DICT if a
373 preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
374 corrupted (input stream not conforming to the zlib format or incorrect
375 adler32 checksum), Z_STREAM_ERROR if the stream structure was inconsistent
376 (for example if next_in or next_out was NULL), Z_MEM_ERROR if there was not
377 enough memory, Z_BUF_ERROR if no progress is possible or if there was not
378 enough room in the output buffer when Z_FINISH is used. In the Z_DATA_ERROR
379 case, the application may then call inflateSync to look for a good
380 compression block.
381*/
382
383
384extern int zlib_inflateEnd (z_streamp strm);
385/*
386 All dynamically allocated data structures for this stream are freed.
387 This function discards any unprocessed input and does not flush any
388 pending output.
389
390 inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state
391 was inconsistent. In the error case, msg may be set but then points to a
392 static string (which must not be deallocated).
393*/
394
395 /* Advanced functions */
396
397/*
398 The following functions are needed only in some special applications.
399*/
400
401/*
402extern int deflateInit2 (z_streamp strm,
403 int level,
404 int method,
405 int windowBits,
406 int memLevel,
407 int strategy);
408
409 This is another version of deflateInit with more compression options. The
410 fields next_in, zalloc, zfree and opaque must be initialized before by
411 the caller.
412
413 The method parameter is the compression method. It must be Z_DEFLATED in
414 this version of the library.
415
416 The windowBits parameter is the base two logarithm of the window size
417 (the size of the history buffer). It should be in the range 8..15 for this
418 version of the library. Larger values of this parameter result in better
419 compression at the expense of memory usage. The default value is 15 if
420 deflateInit is used instead.
421
422 The memLevel parameter specifies how much memory should be allocated
423 for the internal compression state. memLevel=1 uses minimum memory but
424 is slow and reduces compression ratio; memLevel=9 uses maximum memory
425 for optimal speed. The default value is 8. See zconf.h for total memory
426 usage as a function of windowBits and memLevel.
427
428 The strategy parameter is used to tune the compression algorithm. Use the
429 value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
430 filter (or predictor), or Z_HUFFMAN_ONLY to force Huffman encoding only (no
431 string match). Filtered data consists mostly of small values with a
432 somewhat random distribution. In this case, the compression algorithm is
433 tuned to compress them better. The effect of Z_FILTERED is to force more
434 Huffman coding and less string matching; it is somewhat intermediate
435 between Z_DEFAULT and Z_HUFFMAN_ONLY. The strategy parameter only affects
436 the compression ratio but not the correctness of the compressed output even
437 if it is not set appropriately.
438
439 deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
440 memory, Z_STREAM_ERROR if a parameter is invalid (such as an invalid
441 method). msg is set to null if there is no error message. deflateInit2 does
442 not perform any compression: this will be done by deflate().
443*/
444
445extern int zlib_deflateSetDictionary (z_streamp strm,
446 const Byte *dictionary,
447 uInt dictLength);
448/*
449 Initializes the compression dictionary from the given byte sequence
450 without producing any compressed output. This function must be called
451 immediately after deflateInit, deflateInit2 or deflateReset, before any
452 call of deflate. The compressor and decompressor must use exactly the same
453 dictionary (see inflateSetDictionary).
454
455 The dictionary should consist of strings (byte sequences) that are likely
456 to be encountered later in the data to be compressed, with the most commonly
457 used strings preferably put towards the end of the dictionary. Using a
458 dictionary is most useful when the data to be compressed is short and can be
459 predicted with good accuracy; the data can then be compressed better than
460 with the default empty dictionary.
461
462 Depending on the size of the compression data structures selected by
463 deflateInit or deflateInit2, a part of the dictionary may in effect be
464 discarded, for example if the dictionary is larger than the window size in
465 deflate or deflate2. Thus the strings most likely to be useful should be
466 put at the end of the dictionary, not at the front.
467
468 Upon return of this function, strm->adler is set to the Adler32 value
469 of the dictionary; the decompressor may later use this value to determine
470 which dictionary has been used by the compressor. (The Adler32 value
471 applies to the whole dictionary even if only a subset of the dictionary is
472 actually used by the compressor.)
473
474 deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
475 parameter is invalid (such as NULL dictionary) or the stream state is
476 inconsistent (for example if deflate has already been called for this stream
477 or if the compression method is bsort). deflateSetDictionary does not
478 perform any compression: this will be done by deflate().
479*/
480
481extern int zlib_deflateCopy (z_streamp dest, z_streamp source);
482/*
483 Sets the destination stream as a complete copy of the source stream.
484
485 This function can be useful when several compression strategies will be
486 tried, for example when there are several ways of pre-processing the input
487 data with a filter. The streams that will be discarded should then be freed
488 by calling deflateEnd. Note that deflateCopy duplicates the internal
489 compression state which can be quite large, so this strategy is slow and
490 can consume lots of memory.
491
492 deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
493 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
494 (such as zalloc being NULL). msg is left unchanged in both source and
495 destination.
496*/
497
498extern int zlib_deflateReset (z_streamp strm);
499/*
500 This function is equivalent to deflateEnd followed by deflateInit,
501 but does not free and reallocate all the internal compression state.
502 The stream will keep the same compression level and any other attributes
503 that may have been set by deflateInit2.
504
505 deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
506 stream state was inconsistent (such as zalloc or state being NULL).
507*/
508
509extern int zlib_deflateParams (z_streamp strm, int level, int strategy);
510/*
511 Dynamically update the compression level and compression strategy. The
512 interpretation of level and strategy is as in deflateInit2. This can be
513 used to switch between compression and straight copy of the input data, or
514 to switch to a different kind of input data requiring a different
515 strategy. If the compression level is changed, the input available so far
516 is compressed with the old level (and may be flushed); the new level will
517 take effect only at the next call of deflate().
518
519 Before the call of deflateParams, the stream state must be set as for
520 a call of deflate(), since the currently available input may have to
521 be compressed and flushed. In particular, strm->avail_out must be non-zero.
522
523 deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source
524 stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR
525 if strm->avail_out was zero.
526*/
527
528/*
529extern int inflateInit2 (z_streamp strm, int windowBits);
530
531 This is another version of inflateInit with an extra parameter. The
532 fields next_in, avail_in, zalloc, zfree and opaque must be initialized
533 before by the caller.
534
535 The windowBits parameter is the base two logarithm of the maximum window
536 size (the size of the history buffer). It should be in the range 8..15 for
537 this version of the library. The default value is 15 if inflateInit is used
538 instead. If a compressed stream with a larger window size is given as
539 input, inflate() will return with the error code Z_DATA_ERROR instead of
540 trying to allocate a larger window.
541
542 inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
543 memory, Z_STREAM_ERROR if a parameter is invalid (such as a negative
544 memLevel). msg is set to null if there is no error message. inflateInit2
545 does not perform any decompression apart from reading the zlib header if
546 present: this will be done by inflate(). (So next_in and avail_in may be
547 modified, but next_out and avail_out are unchanged.)
548*/
549
550extern int zlib_inflateSetDictionary (z_streamp strm,
551 const Byte *dictionary,
552 uInt dictLength);
553/*
554 Initializes the decompression dictionary from the given uncompressed byte
555 sequence. This function must be called immediately after a call of inflate
556 if this call returned Z_NEED_DICT. The dictionary chosen by the compressor
557 can be determined from the Adler32 value returned by this call of
558 inflate. The compressor and decompressor must use exactly the same
559 dictionary (see deflateSetDictionary).
560
561 inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
562 parameter is invalid (such as NULL dictionary) or the stream state is
563 inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
564 expected one (incorrect Adler32 value). inflateSetDictionary does not
565 perform any decompression: this will be done by subsequent calls of
566 inflate().
567*/
568
569extern int zlib_inflateSync (z_streamp strm);
570/*
571 Skips invalid compressed data until a full flush point (see above the
572 description of deflate with Z_FULL_FLUSH) can be found, or until all
573 available input is skipped. No output is provided.
574
575 inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR
576 if no more input was provided, Z_DATA_ERROR if no flush point has been found,
577 or Z_STREAM_ERROR if the stream structure was inconsistent. In the success
578 case, the application may save the current current value of total_in which
579 indicates where valid compressed data was found. In the error case, the
580 application may repeatedly call inflateSync, providing more input each time,
581 until success or end of the input data.
582*/
583
584extern int zlib_inflateReset (z_streamp strm);
585/*
586 This function is equivalent to inflateEnd followed by inflateInit,
587 but does not free and reallocate all the internal decompression state.
588 The stream will keep attributes that may have been set by inflateInit2.
589
590 inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
591 stream state was inconsistent (such as zalloc or state being NULL).
592*/
593
594extern int zlib_inflateIncomp (z_stream *strm);
595/*
596 This function adds the data at next_in (avail_in bytes) to the output
597 history without performing any output. There must be no pending output,
598 and the decompressor must be expecting to see the start of a block.
599 Calling this function is equivalent to decompressing a stored block
600 containing the data at next_in (except that the data is not output).
601*/
602
603 /* various hacks, don't look :) */
604
605/* deflateInit and inflateInit are macros to allow checking the zlib version
606 * and the compiler's view of z_stream:
607 */
608extern int zlib_deflateInit_ (z_streamp strm, int level,
609 const char *version, int stream_size);
610extern int zlib_inflateInit_ (z_streamp strm,
611 const char *version, int stream_size);
612extern int zlib_deflateInit2_ (z_streamp strm, int level, int method,
613 int windowBits, int memLevel,
614 int strategy, const char *version,
615 int stream_size);
616extern int zlib_inflateInit2_ (z_streamp strm, int windowBits,
617 const char *version, int stream_size);
618#define zlib_deflateInit(strm, level) \
619 zlib_deflateInit_((strm), (level), ZLIB_VERSION, sizeof(z_stream))
620#define zlib_inflateInit(strm) \
621 zlib_inflateInit_((strm), ZLIB_VERSION, sizeof(z_stream))
622#define zlib_deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
623 zlib_deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
624 (strategy), ZLIB_VERSION, sizeof(z_stream))
625#define zlib_inflateInit2(strm, windowBits) \
626 zlib_inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream))
627
628
629#if !defined(_Z_UTIL_H) && !defined(NO_DUMMY_DECL)
630 struct internal_state {int dummy;}; /* hack for buggy compilers */
631#endif
632
633extern const char * zlib_zError (int err);
634extern int zlib_inflateSyncPoint (z_streamp z);
635extern const uLong * zlib_get_crc_table (void);
636
637#endif /* _ZLIB_H */