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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 "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 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 #define zlib_version zlibVersion()
167 /* for compatibility with versions < 1.0.2 */
168
169 /* basic functions */
170
171 ZEXTERN const char * ZEXPORT zlibVersion OF((void));
172 /* The application can compare zlibVersion and ZLIB_VERSION for consistency.
173 If the first character differs, the library code actually used is
174 not compatible with the zlib.h header file used by the application.
175 This check is automatically made by deflateInit and inflateInit.
176 */
177
178 /*
179 ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level));
180
181 Initializes the internal stream state for compression. The fields
182 zalloc, zfree and opaque must be initialized before by the caller.
183 If zalloc and zfree are set to Z_NULL, deflateInit updates them to
184 use default allocation functions.
185
186 The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
187 1 gives best speed, 9 gives best compression, 0 gives no compression at
188 all (the input data is simply copied a block at a time).
189 Z_DEFAULT_COMPRESSION requests a default compromise between speed and
190 compression (currently equivalent to level 6).
191
192 deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not
193 enough memory, Z_STREAM_ERROR if level is not a valid compression level,
194 Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
195 with the version assumed by the caller (ZLIB_VERSION).
196 msg is set to null if there is no error message. deflateInit does not
197 perform any compression: this will be done by deflate().
198 */
199
200
201 ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush));
202 /*
203 deflate compresses as much data as possible, and stops when the input
204 buffer becomes empty or the output buffer becomes full. It may introduce some
205 output latency (reading input without producing any output) except when
206 forced to flush.
207
208 The detailed semantics are as follows. deflate performs one or both of the
209 following actions:
210
211 - Compress more input starting at next_in and update next_in and avail_in
212 accordingly. If not all input can be processed (because there is not
213 enough room in the output buffer), next_in and avail_in are updated and
214 processing will resume at this point for the next call of deflate().
215
216 - Provide more output starting at next_out and update next_out and avail_out
217 accordingly. This action is forced if the parameter flush is non zero.
218 Forcing flush frequently degrades the compression ratio, so this parameter
219 should be set only when necessary (in interactive applications).
220 Some output may be provided even if flush is not set.
221
222 Before the call of deflate(), the application should ensure that at least
223 one of the actions is possible, by providing more input and/or consuming
224 more output, and updating avail_in or avail_out accordingly; avail_out
225 should never be zero before the call. The application can consume the
226 compressed output when it wants, for example when the output buffer is full
227 (avail_out == 0), or after each call of deflate(). If deflate returns Z_OK
228 and with zero avail_out, it must be called again after making room in the
229 output buffer because there might be more output pending.
230
231 If the parameter flush is set to Z_SYNC_FLUSH, all pending output is
232 flushed to the output buffer and the output is aligned on a byte boundary, so
233 that the decompressor can get all input data available so far. (In particular
234 avail_in is zero after the call if enough output space has been provided
235 before the call.) Flushing may degrade compression for some compression
236 algorithms and so it should be used only when necessary.
237
238 If flush is set to Z_FULL_FLUSH, all output is flushed as with
239 Z_SYNC_FLUSH, and the compression state is reset so that decompression can
240 restart from this point if previous compressed data has been damaged or if
241 random access is desired. Using Z_FULL_FLUSH too often can seriously degrade
242 the compression.
243
244 If deflate returns with avail_out == 0, this function must be called again
245 with the same value of the flush parameter and more output space (updated
246 avail_out), until the flush is complete (deflate returns with non-zero
247 avail_out).
248
249 If the parameter flush is set to Z_FINISH, pending input is processed,
250 pending output is flushed and deflate returns with Z_STREAM_END if there
251 was enough output space; if deflate returns with Z_OK, this function must be
252 called again with Z_FINISH and more output space (updated avail_out) but no
253 more input data, until it returns with Z_STREAM_END or an error. After
254 deflate has returned Z_STREAM_END, the only possible operations on the
255 stream are deflateReset or deflateEnd.
256
257 Z_FINISH can be used immediately after deflateInit if all the compression
258 is to be done in a single step. In this case, avail_out must be at least
259 0.1% larger than avail_in plus 12 bytes. If deflate does not return
260 Z_STREAM_END, then it must be called again as described above.
261
262 deflate() sets strm->adler to the adler32 checksum of all input read
263 so far (that is, total_in bytes).
264
265 deflate() may update data_type if it can make a good guess about
266 the input data type (Z_ASCII or Z_BINARY). In doubt, the data is considered
267 binary. This field is only for information purposes and does not affect
268 the compression algorithm in any manner.
269
270 deflate() returns Z_OK if some progress has been made (more input
271 processed or more output produced), Z_STREAM_END if all input has been
272 consumed and all output has been produced (only when flush is set to
273 Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
274 if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible
275 (for example avail_in or avail_out was zero).
276 */
277
278
279 ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm));
280 /*
281 All dynamically allocated data structures for this stream are freed.
282 This function discards any unprocessed input and does not flush any
283 pending output.
284
285 deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
286 stream state was inconsistent, Z_DATA_ERROR if the stream was freed
287 prematurely (some input or output was discarded). In the error case,
288 msg may be set but then points to a static string (which must not be
289 deallocated).
290 */
291
292
293 /*
294 ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm));
295
296 Initializes the internal stream state for decompression. The fields
297 next_in, avail_in, zalloc, zfree and opaque must be initialized before by
298 the caller. If next_in is not Z_NULL and avail_in is large enough (the exact
299 value depends on the compression method), inflateInit determines the
300 compression method from the zlib header and allocates all data structures
301 accordingly; otherwise the allocation will be deferred to the first call of
302 inflate. If zalloc and zfree are set to Z_NULL, inflateInit updates them to
303 use default allocation functions.
304
305 inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
306 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
307 version assumed by the caller. msg is set to null if there is no error
308 message. inflateInit does not perform any decompression apart from reading
309 the zlib header if present: this will be done by inflate(). (So next_in and
310 avail_in may be modified, but next_out and avail_out are unchanged.)
311 */
312
313
314 ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush));
315 /*
316 inflate decompresses as much data as possible, and stops when the input
317 buffer becomes empty or the output buffer becomes full. It may some
318 introduce some output latency (reading input without producing any output)
319 except when forced to flush.
320
321 The detailed semantics are as follows. inflate performs one or both of the
322 following actions:
323
324 - Decompress more input starting at next_in and update next_in and avail_in
325 accordingly. If not all input can be processed (because there is not
326 enough room in the output buffer), next_in is updated and processing
327 will resume at this point for the next call of inflate().
328
329 - Provide more output starting at next_out and update next_out and avail_out
330 accordingly. inflate() provides as much output as possible, until there
331 is no more input data or no more space in the output buffer (see below
332 about the flush parameter).
333
334 Before the call of inflate(), the application should ensure that at least
335 one of the actions is possible, by providing more input and/or consuming
336 more output, and updating the next_* and avail_* values accordingly.
337 The application can consume the uncompressed output when it wants, for
338 example when the output buffer is full (avail_out == 0), or after each
339 call of inflate(). If inflate returns Z_OK and with zero avail_out, it
340 must be called again after making room in the output buffer because there
341 might be more output pending.
342
343 If the parameter flush is set to Z_SYNC_FLUSH, inflate flushes as much
344 output as possible to the output buffer. The flushing behavior of inflate is
345 not specified for values of the flush parameter other than Z_SYNC_FLUSH
346 and Z_FINISH, but the current implementation actually flushes as much output
347 as possible anyway.
348
349 inflate() should normally be called until it returns Z_STREAM_END or an
350 error. However if all decompression is to be performed in a single step
351 (a single call of inflate), the parameter flush should be set to
352 Z_FINISH. In this case all pending input is processed and all pending
353 output is flushed; avail_out must be large enough to hold all the
354 uncompressed data. (The size of the uncompressed data may have been saved
355 by the compressor for this purpose.) The next operation on this stream must
356 be inflateEnd to deallocate the decompression state. The use of Z_FINISH
357 is never required, but can be used to inform inflate that a faster routine
358 may be used for the single inflate() call.
359
360 If a preset dictionary is needed at this point (see inflateSetDictionary
361 below), inflate sets strm-adler to the adler32 checksum of the
362 dictionary chosen by the compressor and returns Z_NEED_DICT; otherwise
363 it sets strm->adler to the adler32 checksum of all output produced
364 so far (that is, total_out bytes) and returns Z_OK, Z_STREAM_END or
365 an error code as described below. At the end of the stream, inflate()
366 checks that its computed adler32 checksum is equal to that saved by the
367 compressor and returns Z_STREAM_END only if the checksum is correct.
368
369 inflate() returns Z_OK if some progress has been made (more input processed
370 or more output produced), Z_STREAM_END if the end of the compressed data has
371 been reached and all uncompressed output has been produced, Z_NEED_DICT if a
372 preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
373 corrupted (input stream not conforming to the zlib format or incorrect
374 adler32 checksum), Z_STREAM_ERROR if the stream structure was inconsistent
375 (for example if next_in or next_out was NULL), Z_MEM_ERROR if there was not
376 enough memory, Z_BUF_ERROR if no progress is possible or if there was not
377 enough room in the output buffer when Z_FINISH is used. In the Z_DATA_ERROR
378 case, the application may then call inflateSync to look for a good
379 compression block.
380 */
381
382
383 ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm));
384 /*
385 All dynamically allocated data structures for this stream are freed.
386 This function discards any unprocessed input and does not flush any
387 pending output.
388
389 inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state
390 was inconsistent. In the error case, msg may be set but then points to a
391 static string (which must not be deallocated).
392 */
393
394 /* Advanced functions */
395
396 /*
397 The following functions are needed only in some special applications.
398 */
399
400 /*
401 ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm,
402 int level,
403 int method,
404 int windowBits,
405 int memLevel,
406 int strategy));
407
408 This is another version of deflateInit with more compression options. The
409 fields next_in, zalloc, zfree and opaque must be initialized before by
410 the caller.
411
412 The method parameter is the compression method. It must be Z_DEFLATED in
413 this version of the library.
414
415 The windowBits parameter is the base two logarithm of the window size
416 (the size of the history buffer). It should be in the range 8..15 for this
417 version of the library. Larger values of this parameter result in better
418 compression at the expense of memory usage. The default value is 15 if
419 deflateInit is used instead.
420
421 The memLevel parameter specifies how much memory should be allocated
422 for the internal compression state. memLevel=1 uses minimum memory but
423 is slow and reduces compression ratio; memLevel=9 uses maximum memory
424 for optimal speed. The default value is 8. See zconf.h for total memory
425 usage as a function of windowBits and memLevel.
426
427 The strategy parameter is used to tune the compression algorithm. Use the
428 value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
429 filter (or predictor), or Z_HUFFMAN_ONLY to force Huffman encoding only (no
430 string match). Filtered data consists mostly of small values with a
431 somewhat random distribution. In this case, the compression algorithm is
432 tuned to compress them better. The effect of Z_FILTERED is to force more
433 Huffman coding and less string matching; it is somewhat intermediate
434 between Z_DEFAULT and Z_HUFFMAN_ONLY. The strategy parameter only affects
435 the compression ratio but not the correctness of the compressed output even
436 if it is not set appropriately.
437
438 deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
439 memory, Z_STREAM_ERROR if a parameter is invalid (such as an invalid
440 method). msg is set to null if there is no error message. deflateInit2 does
441 not perform any compression: this will be done by deflate().
442 */
443
444 ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm,
445 const Bytef *dictionary,
446 uInt dictLength));
447 /*
448 Initializes the compression dictionary from the given byte sequence
449 without producing any compressed output. This function must be called
450 immediately after deflateInit, deflateInit2 or deflateReset, before any
451 call of deflate. The compressor and decompressor must use exactly the same
452 dictionary (see inflateSetDictionary).
453
454 The dictionary should consist of strings (byte sequences) that are likely
455 to be encountered later in the data to be compressed, with the most commonly
456 used strings preferably put towards the end of the dictionary. Using a
457 dictionary is most useful when the data to be compressed is short and can be
458 predicted with good accuracy; the data can then be compressed better than
459 with the default empty dictionary.
460
461 Depending on the size of the compression data structures selected by
462 deflateInit or deflateInit2, a part of the dictionary may in effect be
463 discarded, for example if the dictionary is larger than the window size in
464 deflate or deflate2. Thus the strings most likely to be useful should be
465 put at the end of the dictionary, not at the front.
466
467 Upon return of this function, strm->adler is set to the Adler32 value
468 of the dictionary; the decompressor may later use this value to determine
469 which dictionary has been used by the compressor. (The Adler32 value
470 applies to the whole dictionary even if only a subset of the dictionary is
471 actually used by the compressor.)
472
473 deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
474 parameter is invalid (such as NULL dictionary) or the stream state is
475 inconsistent (for example if deflate has already been called for this stream
476 or if the compression method is bsort). deflateSetDictionary does not
477 perform any compression: this will be done by deflate().
478 */
479
480 ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest,
481 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
498 ZEXTERN int ZEXPORT deflateReset OF((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
509 ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm,
510 int level,
511 int strategy));
512 /*
513 Dynamically update the compression level and compression strategy. The
514 interpretation of level and strategy is as in deflateInit2. This can be
515 used to switch between compression and straight copy of the input data, or
516 to switch to a different kind of input data requiring a different
517 strategy. If the compression level is changed, the input available so far
518 is compressed with the old level (and may be flushed); the new level will
519 take effect only at the next call of deflate().
520
521 Before the call of deflateParams, the stream state must be set as for
522 a call of deflate(), since the currently available input may have to
523 be compressed and flushed. In particular, strm->avail_out must be non-zero.
524
525 deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source
526 stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR
527 if strm->avail_out was zero.
528 */
529
530 /*
531 ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm,
532 int windowBits));
533
534 This is another version of inflateInit with an extra parameter. The
535 fields next_in, avail_in, zalloc, zfree and opaque must be initialized
536 before by the caller.
537
538 The windowBits parameter is the base two logarithm of the maximum window
539 size (the size of the history buffer). It should be in the range 8..15 for
540 this version of the library. The default value is 15 if inflateInit is used
541 instead. If a compressed stream with a larger window size is given as
542 input, inflate() will return with the error code Z_DATA_ERROR instead of
543 trying to allocate a larger window.
544
545 inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
546 memory, Z_STREAM_ERROR if a parameter is invalid (such as a negative
547 memLevel). msg is set to null if there is no error message. inflateInit2
548 does not perform any decompression apart from reading the zlib header if
549 present: this will be done by inflate(). (So next_in and avail_in may be
550 modified, but next_out and avail_out are unchanged.)
551 */
552
553 ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm,
554 const Bytef *dictionary,
555 uInt dictLength));
556 /*
557 Initializes the decompression dictionary from the given uncompressed byte
558 sequence. This function must be called immediately after a call of inflate
559 if this call returned Z_NEED_DICT. The dictionary chosen by the compressor
560 can be determined from the Adler32 value returned by this call of
561 inflate. The compressor and decompressor must use exactly the same
562 dictionary (see deflateSetDictionary).
563
564 inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
565 parameter is invalid (such as NULL dictionary) or the stream state is
566 inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
567 expected one (incorrect Adler32 value). inflateSetDictionary does not
568 perform any decompression: this will be done by subsequent calls of
569 inflate().
570 */
571
572 ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm));
573 /*
574 Skips invalid compressed data until a full flush point (see above the
575 description of deflate with Z_FULL_FLUSH) can be found, or until all
576 available input is skipped. No output is provided.
577
578 inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR
579 if no more input was provided, Z_DATA_ERROR if no flush point has been found,
580 or Z_STREAM_ERROR if the stream structure was inconsistent. In the success
581 case, the application may save the current current value of total_in which
582 indicates where valid compressed data was found. In the error case, the
583 application may repeatedly call inflateSync, providing more input each time,
584 until success or end of the input data.
585 */
586
587 ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm));
588 /*
589 This function is equivalent to inflateEnd followed by inflateInit,
590 but does not free and reallocate all the internal decompression state.
591 The stream will keep attributes that may have been set by inflateInit2.
592
593 inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
594 stream state was inconsistent (such as zalloc or state being NULL).
595 */
596
597
598 /* utility functions */
599
600 /*
601 The following utility functions are implemented on top of the
602 basic stream-oriented functions. To simplify the interface, some
603 default options are assumed (compression level and memory usage,
604 standard memory allocation functions). The source code of these
605 utility functions can easily be modified if you need special options.
606 */
607
608 ZEXTERN int ZEXPORT compress OF((Bytef *dest, uLongf *destLen,
609 const Bytef *source, uLong sourceLen));
610 /*
611 Compresses the source buffer into the destination buffer. sourceLen is
612 the byte length of the source buffer. Upon entry, destLen is the total
613 size of the destination buffer, which must be at least 0.1% larger than
614 sourceLen plus 12 bytes. Upon exit, destLen is the actual size of the
615 compressed buffer.
616 This function can be used to compress a whole file at once if the
617 input file is mmap'ed.
618 compress returns Z_OK if success, Z_MEM_ERROR if there was not
619 enough memory, Z_BUF_ERROR if there was not enough room in the output
620 buffer.
621 */
622
623 ZEXTERN int ZEXPORT compress2 OF((Bytef *dest, uLongf *destLen,
624 const Bytef *source, uLong sourceLen,
625 int level));
626 /*
627 Compresses the source buffer into the destination buffer. The level
628 parameter has the same meaning as in deflateInit. sourceLen is the byte
629 length of the source buffer. Upon entry, destLen is the total size of the
630 destination buffer, which must be at least 0.1% larger than sourceLen plus
631 12 bytes. Upon exit, destLen is the actual size of the compressed buffer.
632
633 compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
634 memory, Z_BUF_ERROR if there was not enough room in the output buffer,
635 Z_STREAM_ERROR if the level parameter is invalid.
636 */
637
638 ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen,
639 const Bytef *source, uLong sourceLen));
640 /*
641 Decompresses the source buffer into the destination buffer. sourceLen is
642 the byte length of the source buffer. Upon entry, destLen is the total
643 size of the destination buffer, which must be large enough to hold the
644 entire uncompressed data. (The size of the uncompressed data must have
645 been saved previously by the compressor and transmitted to the decompressor
646 by some mechanism outside the scope of this compression library.)
647 Upon exit, destLen is the actual size of the compressed buffer.
648 This function can be used to decompress a whole file at once if the
649 input file is mmap'ed.
650
651 uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
652 enough memory, Z_BUF_ERROR if there was not enough room in the output
653 buffer, or Z_DATA_ERROR if the input data was corrupted.
654 */
655
656
657 typedef voidp gzFile;
658
659 ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode));
660 /*
661 Opens a gzip (.gz) file for reading or writing. The mode parameter
662 is as in fopen ("rb" or "wb") but can also include a compression level
663 ("wb9") or a strategy: 'f' for filtered data as in "wb6f", 'h' for
664 Huffman only compression as in "wb1h". (See the description
665 of deflateInit2 for more information about the strategy parameter.)
666
667 gzopen can be used to read a file which is not in gzip format; in this
668 case gzread will directly read from the file without decompression.
669
670 gzopen returns NULL if the file could not be opened or if there was
671 insufficient memory to allocate the (de)compression state; errno
672 can be checked to distinguish the two cases (if errno is zero, the
673 zlib error is Z_MEM_ERROR). */
674
675 ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode));
676 /*
677 gzdopen() associates a gzFile with the file descriptor fd. File
678 descriptors are obtained from calls like open, dup, creat, pipe or
679 fileno (in the file has been previously opened with fopen).
680 The mode parameter is as in gzopen.
681 The next call of gzclose on the returned gzFile will also close the
682 file descriptor fd, just like fclose(fdopen(fd), mode) closes the file
683 descriptor fd. If you want to keep fd open, use gzdopen(dup(fd), mode).
684 gzdopen returns NULL if there was insufficient memory to allocate
685 the (de)compression state.
686 */
687
688 ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy));
689 /*
690 Dynamically update the compression level or strategy. See the description
691 of deflateInit2 for the meaning of these parameters.
692 gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not
693 opened for writing.
694 */
695
696 ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len));
697 /*
698 Reads the given number of uncompressed bytes from the compressed file.
699 If the input file was not in gzip format, gzread copies the given number
700 of bytes into the buffer.
701 gzread returns the number of uncompressed bytes actually read (0 for
702 end of file, -1 for error). */
703
704 ZEXTERN int ZEXPORT gzwrite OF((gzFile file,
705 const voidp buf, unsigned len));
706 /*
707 Writes the given number of uncompressed bytes into the compressed file.
708 gzwrite returns the number of uncompressed bytes actually written
709 (0 in case of error).
710 */
711
712 ZEXTERN int ZEXPORTVA gzprintf OF((gzFile file, const char *format, ...));
713 /*
714 Converts, formats, and writes the args to the compressed file under
715 control of the format string, as in fprintf. gzprintf returns the number of
716 uncompressed bytes actually written (0 in case of error).
717 */
718
719 ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s));
720 /*
721 Writes the given null-terminated string to the compressed file, excluding
722 the terminating null character.
723 gzputs returns the number of characters written, or -1 in case of error.
724 */
725
726 ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len));
727 /*
728 Reads bytes from the compressed file until len-1 characters are read, or
729 a newline character is read and transferred to buf, or an end-of-file
730 condition is encountered. The string is then terminated with a null
731 character.
732 gzgets returns buf, or Z_NULL in case of error.
733 */
734
735 ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c));
736 /*
737 Writes c, converted to an unsigned char, into the compressed file.
738 gzputc returns the value that was written, or -1 in case of error.
739 */
740
741 ZEXTERN int ZEXPORT gzgetc OF((gzFile file));
742 /*
743 Reads one byte from the compressed file. gzgetc returns this byte
744 or -1 in case of end of file or error.
745 */
746
747 ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush));
748 /*
749 Flushes all pending output into the compressed file. The parameter
750 flush is as in the deflate() function. The return value is the zlib
751 error number (see function gzerror below). gzflush returns Z_OK if
752 the flush parameter is Z_FINISH and all output could be flushed.
753 gzflush should be called only when strictly necessary because it can
754 degrade compression.
755 */
756
757 ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file,
758 z_off_t offset, int whence));
759 /*
760 Sets the starting position for the next gzread or gzwrite on the
761 given compressed file. The offset represents a number of bytes in the
762 uncompressed data stream. The whence parameter is defined as in lseek(2);
763 the value SEEK_END is not supported.
764 If the file is opened for reading, this function is emulated but can be
765 extremely slow. If the file is opened for writing, only forward seeks are
766 supported; gzseek then compresses a sequence of zeroes up to the new
767 starting position.
768
769 gzseek returns the resulting offset location as measured in bytes from
770 the beginning of the uncompressed stream, or -1 in case of error, in
771 particular if the file is opened for writing and the new starting position
772 would be before the current position.
773 */
774
775 ZEXTERN int ZEXPORT gzrewind OF((gzFile file));
776 /*
777 Rewinds the given file. This function is supported only for reading.
778
779 gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET)
780 */
781
782 ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file));
783 /*
784 Returns the starting position for the next gzread or gzwrite on the
785 given compressed file. This position represents a number of bytes in the
786 uncompressed data stream.
787
788 gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)
789 */
790
791 ZEXTERN int ZEXPORT gzeof OF((gzFile file));
792 /*
793 Returns 1 when EOF has previously been detected reading the given
794 input stream, otherwise zero.
795 */
796
797 ZEXTERN int ZEXPORT gzclose OF((gzFile file));
798 /*
799 Flushes all pending output if necessary, closes the compressed file
800 and deallocates all the (de)compression state. The return value is the zlib
801 error number (see function gzerror below).
802 */
803
804 ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum));
805 /*
806 Returns the error message for the last error which occurred on the
807 given compressed file. errnum is set to zlib error number. If an
808 error occurred in the file system and not in the compression library,
809 errnum is set to Z_ERRNO and the application may consult errno
810 to get the exact error code.
811 */
812
813 /* checksum functions */
814
815 /*
816 These functions are not related to compression but are exported
817 anyway because they might be useful in applications using the
818 compression library.
819 */
820
821 ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len));
822
823 /*
824 Update a running Adler-32 checksum with the bytes buf[0..len-1] and
825 return the updated checksum. If buf is NULL, this function returns
826 the required initial value for the checksum.
827 An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
828 much faster. Usage example:
829
830 uLong adler = adler32(0L, Z_NULL, 0);
831
832 while (read_buffer(buffer, length) != EOF) {
833 adler = adler32(adler, buffer, length);
834 }
835 if (adler != original_adler) error();
836 */
837
838 ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len));
839 /*
840 Update a running crc with the bytes buf[0..len-1] and return the updated
841 crc. If buf is NULL, this function returns the required initial value
842 for the crc. Pre- and post-conditioning (one's complement) is performed
843 within this function so it shouldn't be done by the application.
844 Usage example:
845
846 uLong crc = crc32(0L, Z_NULL, 0);
847
848 while (read_buffer(buffer, length) != EOF) {
849 crc = crc32(crc, buffer, length);
850 }
851 if (crc != original_crc) error();
852 */
853
854
855 /* various hacks, don't look :) */
856
857 /* deflateInit and inflateInit are macros to allow checking the zlib version
858 * and the compiler's view of z_stream:
859 */
860 ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level,
861 const char *version, int stream_size));
862 ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm,
863 const char *version, int stream_size));
864 ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method,
865 int windowBits, int memLevel,
866 int strategy, const char *version,
867 int stream_size));
868 ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits,
869 const char *version, int stream_size));
870 #define deflateInit(strm, level) \
871 deflateInit_((strm), (level), ZLIB_VERSION, sizeof(z_stream))
872 #define inflateInit(strm) \
873 inflateInit_((strm), ZLIB_VERSION, sizeof(z_stream))
874 #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
875 deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
876 (strategy), ZLIB_VERSION, sizeof(z_stream))
877 #define inflateInit2(strm, windowBits) \
878 inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream))
879
880
881 #if !defined(_Z_UTIL_H) && !defined(NO_DUMMY_DECL)
882 struct internal_state {int dummy;}; /* hack for buggy compilers */
883 #endif
884
885 ZEXTERN const char * ZEXPORT zError OF((int err));
886 ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp z));
887 ZEXTERN const uLongf * ZEXPORT get_crc_table OF((void));
888
889 #ifdef __cplusplus
890 }
891 #endif
892
893 #endif /* _ZLIB_H */