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1 /* zlib.h -- interface of the 'zlib' general purpose compression library
2 version 1.1.2, March 19th, 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 "../zlib/zconf.h"
35
36 #ifdef __cplusplus
37 extern "C" {
38 #endif
39
40 #define ZLIB_VERSION "1.1.2"
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 extern 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 extern 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 extern 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 */
276
277
278 extern int ZEXPORT deflateEnd OF((z_streamp strm));
279 /*
280 All dynamically allocated data structures for this stream are freed.
281 This function discards any unprocessed input and does not flush any
282 pending output.
283
284 deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
285 stream state was inconsistent, Z_DATA_ERROR if the stream was freed
286 prematurely (some input or output was discarded). In the error case,
287 msg may be set but then points to a static string (which must not be
288 deallocated).
289 */
290
291
292 /*
293 extern int ZEXPORT inflateInit OF((z_streamp strm));
294
295 Initializes the internal stream state for decompression. The fields
296 next_in, avail_in, zalloc, zfree and opaque must be initialized before by
297 the caller. If next_in is not Z_NULL and avail_in is large enough (the exact
298 value depends on the compression method), inflateInit determines the
299 compression method from the zlib header and allocates all data structures
300 accordingly; otherwise the allocation will be deferred to the first call of
301 inflate. If zalloc and zfree are set to Z_NULL, inflateInit updates them to
302 use default allocation functions.
303
304 inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
305 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
306 version assumed by the caller. msg is set to null if there is no error
307 message. inflateInit does not perform any decompression apart from reading
308 the zlib header if present: this will be done by inflate(). (So next_in and
309 avail_in may be modified, but next_out and avail_out are unchanged.)
310 */
311
312
313 extern int ZEXPORT inflate OF((z_streamp strm, int flush));
314 /*
315 inflate decompresses as much data as possible, and stops when the input
316 buffer becomes empty or the output buffer becomes full. It may some
317 introduce some output latency (reading input without producing any output)
318 except when forced to flush.
319
320 The detailed semantics are as follows. inflate performs one or both of the
321 following actions:
322
323 - Decompress more input starting at next_in and update next_in and avail_in
324 accordingly. If not all input can be processed (because there is not
325 enough room in the output buffer), next_in is updated and processing
326 will resume at this point for the next call of inflate().
327
328 - Provide more output starting at next_out and update next_out and avail_out
329 accordingly. inflate() provides as much output as possible, until there
330 is no more input data or no more space in the output buffer (see below
331 about the flush parameter).
332
333 Before the call of inflate(), the application should ensure that at least
334 one of the actions is possible, by providing more input and/or consuming
335 more output, and updating the next_* and avail_* values accordingly.
336 The application can consume the uncompressed output when it wants, for
337 example when the output buffer is full (avail_out == 0), or after each
338 call of inflate(). If inflate returns Z_OK and with zero avail_out, it
339 must be called again after making room in the output buffer because there
340 might be more output pending.
341
342 If the parameter flush is set to Z_SYNC_FLUSH, inflate flushes as much
343 output as possible to the output buffer. The flushing behavior of inflate is
344 not specified for values of the flush parameter other than Z_SYNC_FLUSH
345 and Z_FINISH, but the current implementation actually flushes as much output
346 as possible anyway.
347
348 inflate() should normally be called until it returns Z_STREAM_END or an
349 error. However if all decompression is to be performed in a single step
350 (a single call of inflate), the parameter flush should be set to
351 Z_FINISH. In this case all pending input is processed and all pending
352 output is flushed; avail_out must be large enough to hold all the
353 uncompressed data. (The size of the uncompressed data may have been saved
354 by the compressor for this purpose.) The next operation on this stream must
355 be inflateEnd to deallocate the decompression state. The use of Z_FINISH
356 is never required, but can be used to inform inflate that a faster routine
357 may be used for the single inflate() call.
358
359 If a preset dictionary is needed at this point (see inflateSetDictionary
360 below), inflate sets strm-adler to the adler32 checksum of the
361 dictionary chosen by the compressor and returns Z_NEED_DICT; otherwise
362 it sets strm->adler to the adler32 checksum of all output produced
363 so far (that is, total_out bytes) and returns Z_OK, Z_STREAM_END or
364 an error code as described below. At the end of the stream, inflate()
365 checks that its computed adler32 checksum is equal to that saved by the
366 compressor and returns Z_STREAM_END only if the checksum is correct.
367
368 inflate() returns Z_OK if some progress has been made (more input processed
369 or more output produced), Z_STREAM_END if the end of the compressed data has
370 been reached and all uncompressed output has been produced, Z_NEED_DICT if a
371 preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
372 corrupted (input stream not conforming to the zlib format or incorrect
373 adler32 checksum), Z_STREAM_ERROR if the stream structure was inconsistent
374 (for example if next_in or next_out was NULL), Z_MEM_ERROR if there was not
375 enough memory, Z_BUF_ERROR if no progress is possible or if there was not
376 enough room in the output buffer when Z_FINISH is used. In the Z_DATA_ERROR
377 case, the application may then call inflateSync to look for a good
378 compression block.
379 */
380
381
382 extern int ZEXPORT inflateEnd OF((z_streamp strm));
383 /*
384 All dynamically allocated data structures for this stream are freed.
385 This function discards any unprocessed input and does not flush any
386 pending output.
387
388 inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state
389 was inconsistent. In the error case, msg may be set but then points to a
390 static string (which must not be deallocated).
391 */
392
393 /* Advanced functions */
394
395 /*
396 The following functions are needed only in some special applications.
397 */
398
399 /*
400 extern int ZEXPORT deflateInit2 OF((z_streamp strm,
401 int level,
402 int method,
403 int windowBits,
404 int memLevel,
405 int strategy));
406
407 This is another version of deflateInit with more compression options. The
408 fields next_in, zalloc, zfree and opaque must be initialized before by
409 the caller.
410
411 The method parameter is the compression method. It must be Z_DEFLATED in
412 this version of the library.
413
414 The windowBits parameter is the base two logarithm of the window size
415 (the size of the history buffer). It should be in the range 8..15 for this
416 version of the library. Larger values of this parameter result in better
417 compression at the expense of memory usage. The default value is 15 if
418 deflateInit is used instead.
419
420 The memLevel parameter specifies how much memory should be allocated
421 for the internal compression state. memLevel=1 uses minimum memory but
422 is slow and reduces compression ratio; memLevel=9 uses maximum memory
423 for optimal speed. The default value is 8. See zconf.h for total memory
424 usage as a function of windowBits and memLevel.
425
426 The strategy parameter is used to tune the compression algorithm. Use the
427 value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
428 filter (or predictor), or Z_HUFFMAN_ONLY to force Huffman encoding only (no
429 string match). Filtered data consists mostly of small values with a
430 somewhat random distribution. In this case, the compression algorithm is
431 tuned to compress them better. The effect of Z_FILTERED is to force more
432 Huffman coding and less string matching; it is somewhat intermediate
433 between Z_DEFAULT and Z_HUFFMAN_ONLY. The strategy parameter only affects
434 the compression ratio but not the correctness of the compressed output even
435 if it is not set appropriately.
436
437 deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
438 memory, Z_STREAM_ERROR if a parameter is invalid (such as an invalid
439 method). msg is set to null if there is no error message. deflateInit2 does
440 not perform any compression: this will be done by deflate().
441 */
442
443 extern int ZEXPORT deflateSetDictionary OF((z_streamp strm,
444 const Bytef *dictionary,
445 uInt dictLength));
446 /*
447 Initializes the compression dictionary from the given byte sequence
448 without producing any compressed output. This function must be called
449 immediately after deflateInit or deflateInit2, before any call of
450 deflate. The compressor and decompressor must use exactly the same
451 dictionary (see inflateSetDictionary).
452
453 The dictionary should consist of strings (byte sequences) that are likely
454 to be encountered later in the data to be compressed, with the most commonly
455 used strings preferably put towards the end of the dictionary. Using a
456 dictionary is most useful when the data to be compressed is short and can be
457 predicted with good accuracy; the data can then be compressed better than
458 with the default empty dictionary.
459
460 Depending on the size of the compression data structures selected by
461 deflateInit or deflateInit2, a part of the dictionary may in effect be
462 discarded, for example if the dictionary is larger than the window size in
463 deflate or deflate2. Thus the strings most likely to be useful should be
464 put at the end of the dictionary, not at the front.
465
466 Upon return of this function, strm->adler is set to the Adler32 value
467 of the dictionary; the decompressor may later use this value to determine
468 which dictionary has been used by the compressor. (The Adler32 value
469 applies to the whole dictionary even if only a subset of the dictionary is
470 actually used by the compressor.)
471
472 deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
473 parameter is invalid (such as NULL dictionary) or the stream state is
474 inconsistent (for example if deflate has already been called for this stream
475 or if the compression method is bsort). deflateSetDictionary does not
476 perform any compression: this will be done by deflate().
477 */
478
479 extern int ZEXPORT deflateCopy OF((z_streamp dest,
480 z_streamp source));
481 /*
482 Sets the destination stream as a complete copy of the source stream.
483
484 This function can be useful when several compression strategies will be
485 tried, for example when there are several ways of pre-processing the input
486 data with a filter. The streams that will be discarded should then be freed
487 by calling deflateEnd. Note that deflateCopy duplicates the internal
488 compression state which can be quite large, so this strategy is slow and
489 can consume lots of memory.
490
491 deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
492 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
493 (such as zalloc being NULL). msg is left unchanged in both source and
494 destination.
495 */
496
497 extern int ZEXPORT deflateReset OF((z_streamp strm));
498 /*
499 This function is equivalent to deflateEnd followed by deflateInit,
500 but does not free and reallocate all the internal compression state.
501 The stream will keep the same compression level and any other attributes
502 that may have been set by deflateInit2.
503
504 deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
505 stream state was inconsistent (such as zalloc or state being NULL).
506 */
507
508 extern int ZEXPORT deflateParams OF((z_streamp strm, int level, int strategy));
509 /*
510 Dynamically update the compression level and compression strategy. The
511 interpretation of level and strategy is as in deflateInit2. This can be
512 used to switch between compression and straight copy of the input data, or
513 to switch to a different kind of input data requiring a different
514 strategy. If the compression level is changed, the input available so far
515 is compressed with the old level (and may be flushed); the new level will
516 take effect only at the next call of deflate().
517
518 Before the call of deflateParams, the stream state must be set as for
519 a call of deflate(), since the currently available input may have to
520 be compressed and flushed. In particular, strm->avail_out must be non-zero.
521
522 deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source
523 stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR
524 if strm->avail_out was zero.
525 */
526
527 /*
528 extern int ZEXPORT inflateInit2 OF((z_streamp strm,
529 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
550 extern int ZEXPORT inflateSetDictionary OF((z_streamp strm,
551 const Bytef *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
569 extern int ZEXPORT inflateSync OF((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
584 extern int ZEXPORT inflateReset OF((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
594
595 /* utility functions */
596
597 /*
598 The following utility functions are implemented on top of the
599 basic stream-oriented functions. To simplify the interface, some
600 default options are assumed (compression level and memory usage,
601 standard memory allocation functions). The source code of these
602 utility functions can easily be modified if you need special options.
603 */
604
605 extern int ZEXPORT compress OF((Bytef *dest, uLongf *destLen,
606 const Bytef *source, uLong sourceLen));
607 /*
608 Compresses the source buffer into the destination buffer. sourceLen is
609 the byte length of the source buffer. Upon entry, destLen is the total
610 size of the destination buffer, which must be at least 0.1% larger than
611 sourceLen plus 12 bytes. Upon exit, destLen is the actual size of the
612 compressed buffer.
613 This function can be used to compress a whole file at once if the
614 input file is mmap'ed.
615 compress returns Z_OK if success, Z_MEM_ERROR if there was not
616 enough memory, Z_BUF_ERROR if there was not enough room in the output
617 buffer.
618 */
619
620 extern int ZEXPORT compress2 OF((Bytef *dest, uLongf *destLen,
621 const Bytef *source, uLong sourceLen,
622 int level));
623 /*
624 Compresses the source buffer into the destination buffer. The level
625 parameter has the same meaning as in deflateInit. sourceLen is the byte
626 length of the source buffer. Upon entry, destLen is the total size of the
627 destination buffer, which must be at least 0.1% larger than sourceLen plus
628 12 bytes. Upon exit, destLen is the actual size of the compressed buffer.
629
630 compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
631 memory, Z_BUF_ERROR if there was not enough room in the output buffer,
632 Z_STREAM_ERROR if the level parameter is invalid.
633 */
634
635 extern int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen,
636 const Bytef *source, uLong sourceLen));
637 /*
638 Decompresses the source buffer into the destination buffer. sourceLen is
639 the byte length of the source buffer. Upon entry, destLen is the total
640 size of the destination buffer, which must be large enough to hold the
641 entire uncompressed data. (The size of the uncompressed data must have
642 been saved previously by the compressor and transmitted to the decompressor
643 by some mechanism outside the scope of this compression library.)
644 Upon exit, destLen is the actual size of the compressed buffer.
645 This function can be used to decompress a whole file at once if the
646 input file is mmap'ed.
647
648 uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
649 enough memory, Z_BUF_ERROR if there was not enough room in the output
650 buffer, or Z_DATA_ERROR if the input data was corrupted.
651 */
652
653
654 typedef voidp gzFile;
655
656 extern gzFile ZEXPORT gzopen OF((const char *path, const char *mode));
657 /*
658 Opens a gzip (.gz) file for reading or writing. The mode parameter
659 is as in fopen ("rb" or "wb") but can also include a compression level
660 ("wb9") or a strategy: 'f' for filtered data as in "wb6f", 'h' for
661 Huffman only compression as in "wb1h". (See the description
662 of deflateInit2 for more information about the strategy parameter.)
663
664 gzopen can be used to read a file which is not in gzip format; in this
665 case gzread will directly read from the file without decompression.
666
667 gzopen returns NULL if the file could not be opened or if there was
668 insufficient memory to allocate the (de)compression state; errno
669 can be checked to distinguish the two cases (if errno is zero, the
670 zlib error is Z_MEM_ERROR). */
671
672 extern gzFile ZEXPORT gzdopen OF((int fd, const char *mode));
673 /*
674 gzdopen() associates a gzFile with the file descriptor fd. File
675 descriptors are obtained from calls like open, dup, creat, pipe or
676 fileno (in the file has been previously opened with fopen).
677 The mode parameter is as in gzopen.
678 The next call of gzclose on the returned gzFile will also close the
679 file descriptor fd, just like fclose(fdopen(fd), mode) closes the file
680 descriptor fd. If you want to keep fd open, use gzdopen(dup(fd), mode).
681 gzdopen returns NULL if there was insufficient memory to allocate
682 the (de)compression state.
683 */
684
685 extern int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy));
686 /*
687 Dynamically update the compression level or strategy. See the description
688 of deflateInit2 for the meaning of these parameters.
689 gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not
690 opened for writing.
691 */
692
693 extern int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len));
694 /*
695 Reads the given number of uncompressed bytes from the compressed file.
696 If the input file was not in gzip format, gzread copies the given number
697 of bytes into the buffer.
698 gzread returns the number of uncompressed bytes actually read (0 for
699 end of file, -1 for error). */
700
701 extern int ZEXPORT gzwrite OF((gzFile file, const voidp buf, unsigned len));
702 /*
703 Writes the given number of uncompressed bytes into the compressed file.
704 gzwrite returns the number of uncompressed bytes actually written
705 (0 in case of error).
706 */
707
708 extern int ZEXPORTVA gzprintf OF((gzFile file, const char *format, ...));
709 /*
710 Converts, formats, and writes the args to the compressed file under
711 control of the format string, as in fprintf. gzprintf returns the number of
712 uncompressed bytes actually written (0 in case of error).
713 */
714
715 extern int ZEXPORT gzputs OF((gzFile file, const char *s));
716 /*
717 Writes the given null-terminated string to the compressed file, excluding
718 the terminating null character.
719 gzputs returns the number of characters written, or -1 in case of error.
720 */
721
722 extern char * ZEXPORT gzgets OF((gzFile file, char *buf, int len));
723 /*
724 Reads bytes from the compressed file until len-1 characters are read, or
725 a newline character is read and transferred to buf, or an end-of-file
726 condition is encountered. The string is then terminated with a null
727 character.
728 gzgets returns buf, or Z_NULL in case of error.
729 */
730
731 extern int ZEXPORT gzputc OF((gzFile file, int c));
732 /*
733 Writes c, converted to an unsigned char, into the compressed file.
734 gzputc returns the value that was written, or -1 in case of error.
735 */
736
737 extern int ZEXPORT gzgetc OF((gzFile file));
738 /*
739 Reads one byte from the compressed file. gzgetc returns this byte
740 or -1 in case of end of file or error.
741 */
742
743 extern int ZEXPORT gzflush OF((gzFile file, int flush));
744 /*
745 Flushes all pending output into the compressed file. The parameter
746 flush is as in the deflate() function. The return value is the zlib
747 error number (see function gzerror below). gzflush returns Z_OK if
748 the flush parameter is Z_FINISH and all output could be flushed.
749 gzflush should be called only when strictly necessary because it can
750 degrade compression.
751 */
752
753 extern z_off_t ZEXPORT gzseek OF((gzFile file, z_off_t offset, int whence));
754 /*
755 Sets the starting position for the next gzread or gzwrite on the given
756 compressed file. The offset represents a number of bytes in the
757 uncompressed data stream. The whence parameter is defined as in lseek(2);
758 the value SEEK_END is not supported.
759 If the file is opened for reading, this function is emulated but can be
760 extremely slow. If the file is opened for writing, only forward seeks are
761 supported; gzseek then compresses a sequence of zeroes up to the new
762 starting position.
763
764 gzseek returns the resulting offset location as measured in bytes from
765 the beginning of the uncompressed stream, or -1 in case of error, in
766 particular if the file is opened for writing and the new starting position
767 would be before the current position.
768 */
769
770 extern int ZEXPORT gzrewind OF((gzFile file));
771 /*
772 Rewinds the given file. This function is supported only for reading.
773
774 gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET)
775 */
776
777 extern z_off_t ZEXPORT gztell OF((gzFile file));
778 /*
779 Returns the starting position for the next gzread or gzwrite on the
780 given compressed file. This position represents a number of bytes in the
781 uncompressed data stream.
782
783 gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)
784 */
785
786 extern int ZEXPORT gzeof OF((gzFile file));
787 /*
788 Returns 1 when EOF has previously been detected reading the given
789 input stream, otherwise zero.
790 */
791
792 extern int ZEXPORT gzclose OF((gzFile file));
793 /*
794 Flushes all pending output if necessary, closes the compressed file
795 and deallocates all the (de)compression state. The return value is the zlib
796 error number (see function gzerror below).
797 */
798
799 extern const char * ZEXPORT gzerror OF((gzFile file, int *errnum));
800 /*
801 Returns the error message for the last error which occurred on the
802 given compressed file. errnum is set to zlib error number. If an
803 error occurred in the file system and not in the compression library,
804 errnum is set to Z_ERRNO and the application may consult errno
805 to get the exact error code.
806 */
807
808 /* checksum functions */
809
810 /*
811 These functions are not related to compression but are exported
812 anyway because they might be useful in applications using the
813 compression library.
814 */
815
816 extern uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len));
817
818 /*
819 Update a running Adler-32 checksum with the bytes buf[0..len-1] and
820 return the updated checksum. If buf is NULL, this function returns
821 the required initial value for the checksum.
822 An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
823 much faster. Usage example:
824
825 uLong adler = adler32(0L, Z_NULL, 0);
826
827 while (read_buffer(buffer, length) != EOF) {
828 adler = adler32(adler, buffer, length);
829 }
830 if (adler != original_adler) error();
831 */
832
833 extern uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len));
834 /*
835 Update a running crc with the bytes buf[0..len-1] and return the updated
836 crc. If buf is NULL, this function returns the required initial value
837 for the crc. Pre- and post-conditioning (one's complement) is performed
838 within this function so it shouldn't be done by the application.
839 Usage example:
840
841 uLong crc = crc32(0L, Z_NULL, 0);
842
843 while (read_buffer(buffer, length) != EOF) {
844 crc = crc32(crc, buffer, length);
845 }
846 if (crc != original_crc) error();
847 */
848
849
850 /* various hacks, don't look :) */
851
852 /* deflateInit and inflateInit are macros to allow checking the zlib version
853 * and the compiler's view of z_stream:
854 */
855 extern int ZEXPORT deflateInit_ OF((z_streamp strm, int level,
856 const char *version, int stream_size));
857 extern int ZEXPORT inflateInit_ OF((z_streamp strm,
858 const char *version, int stream_size));
859 extern int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method,
860 int windowBits, int memLevel,
861 int strategy, const char *version,
862 int stream_size));
863 extern int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits,
864 const char *version, int stream_size));
865 #define deflateInit(strm, level) \
866 deflateInit_((strm), (level), ZLIB_VERSION, sizeof(z_stream))
867 #define inflateInit(strm) \
868 inflateInit_((strm), ZLIB_VERSION, sizeof(z_stream))
869 #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
870 deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
871 (strategy), ZLIB_VERSION, sizeof(z_stream))
872 #define inflateInit2(strm, windowBits) \
873 inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream))
874
875
876 #if !defined(_Z_UTIL_H) && !defined(NO_DUMMY_DECL)
877 struct internal_state {int dummy;}; /* hack for buggy compilers */
878 #endif
879
880 extern const char * ZEXPORT zError OF((int err));
881 extern int ZEXPORT inflateSyncPoint OF((z_streamp z));
882 extern const uLongf * ZEXPORT get_crc_table OF((void));
883
884 #ifdef __cplusplus
885 }
886 #endif
887
888 #endif /* _ZLIB_H */