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1 /* zlib.h -- interface of the 'zlib' general purpose compression library
2 version 1.0.4, Jul 24th, 1996.
4 Copyright (C) 1995-1996 Jean-loup Gailly and Mark Adler
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.
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:
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.
22 Jean-loup Gailly Mark Adler
23 gzip@prep.ai.mit.edu madler@alumni.caltech.edu
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).
30 /* This file was modified since it was taken from the zlib distribution */
32 #ifndef _ZLIB_H
33 #define _ZLIB_H
35 #ifdef __cplusplus
36 extern "C" {
37 #endif
39 #ifdef MOZILLA_CLIENT
40 #include "jzconf.h"
41 #else
42 #include "zconf.h"
43 #endif
45 #define ZLIB_VERSION "1.0.4"
47 /*
48 The 'zlib' compression library provides in-memory compression and
49 decompression functions, including integrity checks of the uncompressed
50 data. This version of the library supports only one compression method
51 (deflation) but other algorithms may be added later and will have the same
52 stream interface.
54 For compression the application must provide the output buffer and
55 may optionally provide the input buffer for optimization. For decompression,
56 the application must provide the input buffer and may optionally provide
57 the output buffer for optimization.
59 Compression can be done in a single step if the buffers are large
60 enough (for example if an input file is mmap'ed), or can be done by
61 repeated calls of the compression function. In the latter case, the
62 application must provide more input and/or consume the output
63 (providing more output space) before each call.
65 The library does not install any signal handler. It is recommended to
66 add at least a handler for SIGSEGV when decompressing; the library checks
67 the consistency of the input data whenever possible but may go nuts
68 for some forms of corrupted input.
71 typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size));
72 typedef void (*free_func) OF((voidpf opaque, voidpf address));
74 struct internal_state;
76 typedef struct z_stream_s {
77 Bytef *next_in; /* next input byte */
78 uInt avail_in; /* number of bytes available at next_in */
79 uLong total_in; /* total nb of input bytes read so far */
81 Bytef *next_out; /* next output byte should be put there */
82 uInt avail_out; /* remaining free space at next_out */
83 uLong total_out; /* total nb of bytes output so far */
85 char *msg; /* last error message, NULL if no error */
86 struct internal_state FAR *state; /* not visible by applications */
88 alloc_func zalloc; /* used to allocate the internal state */
89 free_func zfree; /* used to free the internal state */
90 voidpf opaque; /* private data object passed to zalloc and zfree */
92 int data_type; /* best guess about the data type: ascii or binary */
93 uLong adler; /* adler32 value of the uncompressed data */
94 uLong reserved; /* reserved for future use */
95 } z_stream;
97 typedef z_stream FAR *z_streamp;
100 The application must update next_in and avail_in when avail_in has
101 dropped to zero. It must update next_out and avail_out when avail_out
102 has dropped to zero. The application must initialize zalloc, zfree and
103 opaque before calling the init function. All other fields are set by the
104 compression library and must not be updated by the application.
106 The opaque value provided by the application will be passed as the first
107 parameter for calls of zalloc and zfree. This can be useful for custom
108 memory management. The compression library attaches no meaning to the
109 opaque value.
111 zalloc must return Z_NULL if there is not enough memory for the object.
112 On 16-bit systems, the functions zalloc and zfree must be able to allocate
113 exactly 65536 bytes, but will not be required to allocate more than this
114 if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS,
115 pointers returned by zalloc for objects of exactly 65536 bytes *must*
116 have their offset normalized to zero. The default allocation function
117 provided by this library ensures this (see zutil.c). To reduce memory
118 requirements and avoid any allocation of 64K objects, at the expense of
119 compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h).
121 The fields total_in and total_out can be used for statistics or
122 progress reports. After compression, total_in holds the total size of
123 the uncompressed data and may be saved for use in the decompressor
124 (particularly if the decompressor wants to decompress everything in
125 a single step).
128 /* constants */
130 #define Z_NO_FLUSH 0
131 #define Z_PARTIAL_FLUSH 1
132 #define Z_SYNC_FLUSH 2
133 #define Z_FULL_FLUSH 3
134 #define Z_FINISH 4
135 /* Allowed flush values; see deflate() below for details */
137 #define Z_OK 0
138 #define Z_STREAM_END 1
139 #define Z_NEED_DICT 2
140 #define Z_ERRNO (-1)
141 #define Z_STREAM_ERROR (-2)
142 #define Z_DATA_ERROR (-3)
143 #define Z_MEM_ERROR (-4)
144 #define Z_BUF_ERROR (-5)
145 #define Z_VERSION_ERROR (-6)
146 /* Return codes for the compression/decompression functions. Negative
147 * values are errors, positive values are used for special but normal events.
150 #define Z_NO_COMPRESSION 0
151 #define Z_BEST_SPEED 1
152 #define Z_BEST_COMPRESSION 9
153 #define Z_DEFAULT_COMPRESSION (-1)
154 /* compression levels */
156 #define Z_FILTERED 1
157 #define Z_HUFFMAN_ONLY 2
158 #define Z_DEFAULT_STRATEGY 0
159 /* compression strategy; see deflateInit2() below for details */
161 #define Z_BINARY 0
162 #define Z_ASCII 1
163 #define Z_UNKNOWN 2
164 /* Possible values of the data_type field */
166 #define Z_DEFLATED 8
167 /* The deflate compression method (the only one supported in this version) */
169 #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */
171 #define zlib_version zlibVersion()
172 /* for compatibility with versions < 1.0.2 */
174 /* basic functions */
176 #ifdef MOZILLA_CLIENT
177 PR_PUBLIC_API(extern const char *) zlibVersion (void);
178 #else
179 extern const char * EXPORT zlibVersion OF((void));
180 #endif
181 /* The application can compare zlibVersion and ZLIB_VERSION for consistency.
182 If the first character differs, the library code actually used is
183 not compatible with the zlib.h header file used by the application.
184 This check is automatically made by deflateInit and inflateInit.
188 extern int EXPORT deflateInit OF((z_streamp strm, int level));
190 Initializes the internal stream state for compression. The fields
191 zalloc, zfree and opaque must be initialized before by the caller.
192 If zalloc and zfree are set to Z_NULL, deflateInit updates them to
193 use default allocation functions.
195 The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
196 1 gives best speed, 9 gives best compression, 0 gives no compression at
197 all (the input data is simply copied a block at a time).
198 Z_DEFAULT_COMPRESSION requests a default compromise between speed and
199 compression (currently equivalent to level 6).
201 deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not
202 enough memory, Z_STREAM_ERROR if level is not a valid compression level,
203 Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
204 with the version assumed by the caller (ZLIB_VERSION).
205 msg is set to null if there is no error message. deflateInit does not
206 perform any compression: this will be done by deflate().
210 #ifdef MOZILLA_CLIENT
211 PR_PUBLIC_API(extern int) deflate (z_streamp strm, int flush);
212 #else
213 extern int EXPORT deflate OF((z_streamp strm, int flush));
214 #endif
216 Performs one or both of the following actions:
218 - Compress more input starting at next_in and update next_in and avail_in
219 accordingly. If not all input can be processed (because there is not
220 enough room in the output buffer), next_in and avail_in are updated and
221 processing will resume at this point for the next call of deflate().
223 - Provide more output starting at next_out and update next_out and avail_out
224 accordingly. This action is forced if the parameter flush is non zero.
225 Forcing flush frequently degrades the compression ratio, so this parameter
226 should be set only when necessary (in interactive applications).
227 Some output may be provided even if flush is not set.
229 Before the call of deflate(), the application should ensure that at least
230 one of the actions is possible, by providing more input and/or consuming
231 more output, and updating avail_in or avail_out accordingly; avail_out
232 should never be zero before the call. The application can consume the
233 compressed output when it wants, for example when the output buffer is full
234 (avail_out == 0), or after each call of deflate(). If deflate returns Z_OK
235 and with zero avail_out, it must be called again after making room in the
236 output buffer because there might be more output pending.
238 If the parameter flush is set to Z_PARTIAL_FLUSH, the current compression
239 block is terminated and flushed to the output buffer so that the
240 decompressor can get all input data available so far. For method 9, a future
241 variant on method 8, the current block will be flushed but not terminated.
242 Z_SYNC_FLUSH has the same effect as partial flush except that the compressed
243 output is byte aligned (the compressor can clear its internal bit buffer)
244 and the current block is always terminated; this can be useful if the
245 compressor has to be restarted from scratch after an interruption (in which
246 case the internal state of the compressor may be lost).
247 If flush is set to Z_FULL_FLUSH, the compression block is terminated, a
248 special marker is output and the compression dictionary is discarded; this
249 is useful to allow the decompressor to synchronize if one compressed block
250 has been damaged (see inflateSync below). Flushing degrades compression and
251 so should be used only when necessary. Using Z_FULL_FLUSH too often can
252 seriously degrade the compression. If deflate returns with avail_out == 0,
253 this function must be called again with the same value of the flush
254 parameter and more output space (updated avail_out), until the flush is
255 complete (deflate returns with non-zero avail_out).
257 If the parameter flush is set to Z_FINISH, pending input is processed,
258 pending output is flushed and deflate returns with Z_STREAM_END if there
259 was enough output space; if deflate returns with Z_OK, this function must be
260 called again with Z_FINISH and more output space (updated avail_out) but no
261 more input data, until it returns with Z_STREAM_END or an error. After
262 deflate has returned Z_STREAM_END, the only possible operations on the
263 stream are deflateReset or deflateEnd.
265 Z_FINISH can be used immediately after deflateInit if all the compression
266 is to be done in a single step. In this case, avail_out must be at least
267 0.1% larger than avail_in plus 12 bytes. If deflate does not return
268 Z_STREAM_END, then it must be called again as described above.
270 deflate() may update data_type if it can make a good guess about
271 the input data type (Z_ASCII or Z_BINARY). In doubt, the data is considered
272 binary. This field is only for information purposes and does not affect
273 the compression algorithm in any manner.
275 deflate() returns Z_OK if some progress has been made (more input
276 processed or more output produced), Z_STREAM_END if all input has been
277 consumed and all output has been produced (only when flush is set to
278 Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
279 if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible.
283 #ifdef MOZILLA_CLIENT
284 PR_PUBLIC_API(extern int) deflateEnd (z_streamp strm);
285 #else
286 extern int EXPORT deflateEnd OF((z_streamp strm));
287 #endif
289 All dynamically allocated data structures for this stream are freed.
290 This function discards any unprocessed input and does not flush any
291 pending output.
293 deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
294 stream state was inconsistent, Z_DATA_ERROR if the stream was freed
295 prematurely (some input or output was discarded). In the error case,
296 msg may be set but then points to a static string (which must not be
297 deallocated).
302 extern int EXPORT inflateInit OF((z_streamp strm));
304 Initializes the internal stream state for decompression. The fields
305 zalloc, zfree and opaque must be initialized before by the caller. If
306 zalloc and zfree are set to Z_NULL, inflateInit updates them to use default
307 allocation functions.
309 inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not
310 enough memory, Z_VERSION_ERROR if the zlib library version is incompatible
311 with the version assumed by the caller. msg is set to null if there is no
312 error message. inflateInit does not perform any decompression: this will be
313 done by inflate().
317 #ifdef MOZILLA_CLIENT
318 PR_PUBLIC_API(extern int) inflate (z_streamp strm, int flush);
319 #else
320 extern int EXPORT inflate OF((z_streamp strm, int flush));
321 #endif
323 Performs one or both of the following actions:
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().
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).
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.
344 If the parameter flush is set to Z_PARTIAL_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_PARTIAL_FLUSH
347 and Z_FINISH, but the current implementation actually flushes as much output
348 as possible anyway.
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.
361 inflate() returns Z_OK if some progress has been made (more input
362 processed or more output produced), Z_STREAM_END if the end of the
363 compressed data has been reached and all uncompressed output has been
364 produced, Z_NEED_DICT if a preset dictionary is needed at this point (see
365 inflateSetDictionary below), Z_DATA_ERROR if the input data was corrupted,
366 Z_STREAM_ERROR if the stream structure was inconsistent (for example if
367 next_in or next_out was NULL), Z_MEM_ERROR if there was not enough memory,
368 Z_BUF_ERROR if no progress is possible or if there was not enough room in
369 the output buffer when Z_FINISH is used. In the Z_DATA_ERROR case, the
370 application may then call inflateSync to look for a good compression block.
371 In the Z_NEED_DICT case, strm->adler is set to the Adler32 value of the
372 dictionary chosen by the compressor.
376 #ifdef MOZILLA_CLIENT
377 PR_PUBLIC_API(extern int) inflateEnd (z_streamp strm);
378 #else
379 extern int EXPORT inflateEnd OF((z_streamp strm));
380 #endif
382 All dynamically allocated data structures for this stream are freed.
383 This function discards any unprocessed input and does not flush any
384 pending output.
386 inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state
387 was inconsistent. In the error case, msg may be set but then points to a
388 static string (which must not be deallocated).
391 /* Advanced functions */
394 The following functions are needed only in some special applications.
398 extern int EXPORT deflateInit2 OF((z_streamp strm,
399 int level,
400 int method,
401 int windowBits,
402 int memLevel,
403 int strategy));
405 This is another version of deflateInit with more compression options. The
406 fields next_in, zalloc, zfree and opaque must be initialized before by
407 the caller.
409 The method parameter is the compression method. It must be Z_DEFLATED in
410 this version of the library. (Method 9 will allow a 64K history buffer and
411 partial block flushes.)
413 The windowBits parameter is the base two logarithm of the window size
414 (the size of the history buffer). It should be in the range 8..15 for this
415 version of the library (the value 16 will be allowed for method 9). Larger
416 values of this parameter result in better compression at the expense of
417 memory usage. The default value is 15 if deflateInit is used instead.
419 The memLevel parameter specifies how much memory should be allocated
420 for the internal compression state. memLevel=1 uses minimum memory but
421 is slow and reduces compression ratio; memLevel=9 uses maximum memory
422 for optimal speed. The default value is 8. See zconf.h for total memory
423 usage as a function of windowBits and memLevel.
425 The strategy parameter is used to tune the compression algorithm. Use the
426 value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
427 filter (or predictor), or Z_HUFFMAN_ONLY to force Huffman encoding only (no
428 string match). Filtered data consists mostly of small values with a
429 somewhat random distribution. In this case, the compression algorithm is
430 tuned to compress them better. The effect of Z_FILTERED is to force more
431 Huffman coding and less string matching; it is somewhat intermediate
432 between Z_DEFAULT and Z_HUFFMAN_ONLY. The strategy parameter only affects
433 the compression ratio but not the correctness of the compressed output even
434 if it is not set appropriately.
436 If next_in is not null, the library will use this buffer to hold also
437 some history information; the buffer must either hold the entire input
438 data, or have at least 1<<(windowBits+1) bytes and be writable. If next_in
439 is null, the library will allocate its own history buffer (and leave next_in
440 null). next_out need not be provided here but must be provided by the
441 application for the next call of deflate().
443 If the history buffer is provided by the application, next_in must
444 must never be changed by the application since the compressor maintains
445 information inside this buffer from call to call; the application
446 must provide more input only by increasing avail_in. next_in is always
447 reset by the library in this case.
449 deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was
450 not enough memory, Z_STREAM_ERROR if a parameter is invalid (such as
451 an invalid method). msg is set to null if there is no error message.
452 deflateInit2 does not perform any compression: this will be done by
453 deflate().
456 #ifdef MOZILLA_CLIENT
457 PR_PUBLIC_API(extern int) deflateSetDictionary (z_streamp strm,
458 const Bytef *dictionary,
459 uInt dictLength);
460 #else
461 extern int EXPORT deflateSetDictionary OF((z_streamp strm,
462 const Bytef *dictionary,
463 uInt dictLength));
464 #endif
466 Initializes the compression dictionary (history buffer) from the given
467 byte sequence without producing any compressed output. This function must
468 be called immediately after deflateInit or deflateInit2, before any call
469 of deflate. The compressor and decompressor must use exactly the same
470 dictionary (see inflateSetDictionary).
471 The dictionary should consist of strings (byte sequences) that are likely
472 to be encountered later in the data to be compressed, with the most commonly
473 used strings preferably put towards the end of the dictionary. Using a
474 dictionary is most useful when the data to be compressed is short and
475 can be predicted with good accuracy; the data can then be compressed better
476 than with the default empty dictionary. In this version of the library,
477 only the last 32K bytes of the dictionary are used.
478 Upon return of this function, strm->adler is set to the Adler32 value
479 of the dictionary; the decompressor may later use this value to determine
480 which dictionary has been used by the compressor. (The Adler32 value
481 applies to the whole dictionary even if only a subset of the dictionary is
482 actually used by the compressor.)
484 deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
485 parameter is invalid (such as NULL dictionary) or the stream state
486 is inconsistent (for example if deflate has already been called for this
487 stream). deflateSetDictionary does not perform any compression: this will
488 be done by deflate().
491 #ifdef MOZILLA_CLIENT
492 PR_PUBLIC_API(extern int) deflateCopy (z_streamp dest, z_streamp source);
493 #else
494 extern int EXPORT deflateCopy OF((z_streamp dest, z_streamp source));
495 #endif
497 Sets the destination stream as a complete copy of the source stream. If
498 the source stream is using an application-supplied history buffer, a new
499 buffer is allocated for the destination stream. The compressed output
500 buffer is always application-supplied. It's the responsibility of the
501 application to provide the correct values of next_out and avail_out for the
502 next call of deflate.
504 This function can be useful when several compression strategies will be
505 tried, for example when there are several ways of pre-processing the input
506 data with a filter. The streams that will be discarded should then be freed
507 by calling deflateEnd. Note that deflateCopy duplicates the internal
508 compression state which can be quite large, so this strategy is slow and
509 can consume lots of memory.
511 deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
512 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
513 (such as zalloc being NULL). msg is left unchanged in both source and
514 destination.
517 #ifdef MOZILLA_CLIENT
518 PR_PUBLIC_API(extern int) deflateReset (z_streamp strm);
519 #else
520 extern int EXPORT deflateReset OF((z_streamp strm));
521 #endif
523 This function is equivalent to deflateEnd followed by deflateInit,
524 but does not free and reallocate all the internal compression state.
525 The stream will keep the same compression level and any other attributes
526 that may have been set by deflateInit2.
528 deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
529 stream state was inconsistent (such as zalloc or state being NULL).
532 #ifdef MOZILLA_CLIENT
533 PR_PUBLIC_API(extern int) deflateParams (z_streamp strm, int level, int strategy);
534 #else
535 extern int EXPORT deflateParams OF((z_streamp strm, int level, int strategy));
536 #endif
538 Dynamically update the compression level and compression strategy.
539 This can be used to switch between compression and straight copy of
540 the input data, or to switch to a different kind of input data requiring
541 a different strategy. If the compression level is changed, the input
542 available so far is compressed with the old level (and may be flushed);
543 the new level will take effect only at the next call of deflate().
545 Before the call of deflateParams, the stream state must be set as for
546 a call of deflate(), since the currently available input may have to
547 be compressed and flushed. In particular, strm->avail_out must be non-zero.
549 deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source
550 stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR
551 if strm->avail_out was zero.
555 extern int EXPORT inflateInit2 OF((z_streamp strm,
556 int windowBits));
558 This is another version of inflateInit with more compression options. The
559 fields next_out, zalloc, zfree and opaque must be initialized before by
560 the caller.
562 The windowBits parameter is the base two logarithm of the maximum window
563 size (the size of the history buffer). It should be in the range 8..15 for
564 this version of the library (the value 16 will be allowed soon). The
565 default value is 15 if inflateInit is used instead. If a compressed stream
566 with a larger window size is given as input, inflate() will return with
567 the error code Z_DATA_ERROR instead of trying to allocate a larger window.
569 If next_out is not null, the library will use this buffer for the history
570 buffer; the buffer must either be large enough to hold the entire output
571 data, or have at least 1<<windowBits bytes. If next_out is null, the
572 library will allocate its own buffer (and leave next_out null). next_in
573 need not be provided here but must be provided by the application for the
574 next call of inflate().
576 If the history buffer is provided by the application, next_out must
577 never be changed by the application since the decompressor maintains
578 history information inside this buffer from call to call; the application
579 can only reset next_out to the beginning of the history buffer when
580 avail_out is zero and all output has been consumed.
582 inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was
583 not enough memory, Z_STREAM_ERROR if a parameter is invalid (such as
584 windowBits < 8). msg is set to null if there is no error message.
585 inflateInit2 does not perform any decompression: this will be done by
586 inflate().
589 #ifdef MOZILLA_CLIENT
590 PR_PUBLIC_API(extern int) inflateSetDictionary (z_streamp strm,
591 const Bytef *dictionary,
592 uInt dictLength);
593 #else
594 extern int EXPORT inflateSetDictionary OF((z_streamp strm,
595 const Bytef *dictionary,
596 uInt dictLength));
597 #endif
599 Initializes the decompression dictionary (history buffer) from the given
600 uncompressed byte sequence. This function must be called immediately after
601 a call of inflate if this call returned Z_NEED_DICT. The dictionary chosen
602 by the compressor can be determined from the Adler32 value returned by this
603 call of inflate. The compressor and decompressor must use exactly the same
604 dictionary (see deflateSetDictionary).
606 inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
607 parameter is invalid (such as NULL dictionary) or the stream state is
608 inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
609 expected one (incorrect Adler32 value). inflateSetDictionary does not
610 perform any decompression: this will be done by subsequent calls of
611 inflate().
614 #ifdef MOZILLA_CLIENT
615 PR_PUBLIC_API(extern int) inflateSync (z_streamp strm);
616 #else
617 extern int EXPORT inflateSync OF((z_streamp strm));
618 #endif
620 Skips invalid compressed data until the special marker (see deflate()
621 above) can be found, or until all available input is skipped. No output
622 is provided.
624 inflateSync returns Z_OK if the special marker has been found, Z_BUF_ERROR
625 if no more input was provided, Z_DATA_ERROR if no marker has been found,
626 or Z_STREAM_ERROR if the stream structure was inconsistent. In the success
627 case, the application may save the current current value of total_in which
628 indicates where valid compressed data was found. In the error case, the
629 application may repeatedly call inflateSync, providing more input each time,
630 until success or end of the input data.
633 #ifdef MOZILLA_CLIENT
634 PR_PUBLIC_API(extern int) inflateReset (z_streamp strm);
635 #else
636 extern int EXPORT inflateReset OF((z_streamp strm));
637 #endif
639 This function is equivalent to inflateEnd followed by inflateInit,
640 but does not free and reallocate all the internal decompression state.
641 The stream will keep attributes that may have been set by inflateInit2.
643 inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
644 stream state was inconsistent (such as zalloc or state being NULL).
648 /* utility functions */
651 The following utility functions are implemented on top of the
652 basic stream-oriented functions. To simplify the interface, some
653 default options are assumed (compression level, window size,
654 standard memory allocation functions). The source code of these
655 utility functions can easily be modified if you need special options.
658 #ifdef MOZILLA_CLIENT
659 PR_PUBLIC_API(extern int) compress (Bytef *dest, uLongf *destLen,
660 const Bytef *source, uLong sourceLen);
661 #else
662 extern int EXPORT compress OF((Bytef *dest, uLongf *destLen,
663 const Bytef *source, uLong sourceLen));
664 #endif
666 Compresses the source buffer into the destination buffer. sourceLen is
667 the byte length of the source buffer. Upon entry, destLen is the total
668 size of the destination buffer, which must be at least 0.1% larger than
669 sourceLen plus 12 bytes. Upon exit, destLen is the actual size of the
670 compressed buffer.
671 This function can be used to compress a whole file at once if the
672 input file is mmap'ed.
673 compress returns Z_OK if success, Z_MEM_ERROR if there was not
674 enough memory, Z_BUF_ERROR if there was not enough room in the output
675 buffer.
678 #ifdef MOZILLA_CLIENT
679 PR_PUBLIC_API(extern int) uncompress (Bytef *dest, uLongf *destLen,
680 const Bytef *source, uLong sourceLen);
681 #else
682 extern int EXPORT uncompress OF((Bytef *dest, uLongf *destLen,
683 const Bytef *source, uLong sourceLen));
684 #endif
686 Decompresses the source buffer into the destination buffer. sourceLen is
687 the byte length of the source buffer. Upon entry, destLen is the total
688 size of the destination buffer, which must be large enough to hold the
689 entire uncompressed data. (The size of the uncompressed data must have
690 been saved previously by the compressor and transmitted to the decompressor
691 by some mechanism outside the scope of this compression library.)
692 Upon exit, destLen is the actual size of the compressed buffer.
693 This function can be used to decompress a whole file at once if the
694 input file is mmap'ed.
696 uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
697 enough memory, Z_BUF_ERROR if there was not enough room in the output
698 buffer, or Z_DATA_ERROR if the input data was corrupted.
702 typedef voidp gzFile;
704 #ifdef MOZILLA_CLIENT
705 PR_PUBLIC_API(extern gzFile) gzopen (const char *path, const char *mode);
706 #else
707 extern gzFile EXPORT gzopen OF((const char *path, const char *mode));
708 #endif
710 Opens a gzip (.gz) file for reading or writing. The mode parameter
711 is as in fopen ("rb" or "wb") but can also include a compression level
712 ("wb9"). gzopen can be used to read a file which is not in gzip format;
713 in this case gzread will directly read from the file without decompression.
714 gzopen returns NULL if the file could not be opened or if there was
715 insufficient memory to allocate the (de)compression state; errno
716 can be checked to distinguish the two cases (if errno is zero, the
717 zlib error is Z_MEM_ERROR).
720 #ifdef MOZILLA_CLIENT
721 PR_PUBLIC_API(extern gzFile) gzdopen (int fd, const char *mode);
722 #else
723 extern gzFile EXPORT gzdopen OF((int fd, const char *mode));
724 #endif
726 gzdopen() associates a gzFile with the file descriptor fd. File
727 descriptors are obtained from calls like open, dup, creat, pipe or
728 fileno (in the file has been previously opened with fopen).
729 The mode parameter is as in gzopen.
730 The next call of gzclose on the returned gzFile will also close the
731 file descriptor fd, just like fclose(fdopen(fd), mode) closes the file
732 descriptor fd. If you want to keep fd open, use gzdopen(dup(fd), mode).
733 gzdopen returns NULL if there was insufficient memory to allocate
734 the (de)compression state.
737 #ifdef MOZILLA_CLIENT
738 PR_PUBLIC_API(extern int) gzread (gzFile file, voidp buf, unsigned len);
739 #else
740 extern int EXPORT gzread OF((gzFile file, voidp buf, unsigned len));
741 #endif
743 Reads the given number of uncompressed bytes from the compressed file.
744 If the input file was not in gzip format, gzread copies the given number
745 of bytes into the buffer.
746 gzread returns the number of uncompressed bytes actually read (0 for
747 end of file, -1 for error). */
749 #ifdef MOZILLA_CLIENT
750 PR_PUBLIC_API(extern int) gzwrite (gzFile file, const voidp buf, unsigned len);
751 #else
752 extern int EXPORT gzwrite OF((gzFile file, const voidp buf, unsigned len));
753 #endif
755 Writes the given number of uncompressed bytes into the compressed file.
756 gzwrite returns the number of uncompressed bytes actually written
757 (0 in case of error).
760 #ifdef MOZILLA_CLIENT
761 PR_PUBLIC_API(extern int) gzflush (gzFile file, int flush);
762 #else
763 extern int EXPORT gzflush OF((gzFile file, int flush));
764 #endif
766 Flushes all pending output into the compressed file. The parameter
767 flush is as in the deflate() function. The return value is the zlib
768 error number (see function gzerror below). gzflush returns Z_OK if
769 the flush parameter is Z_FINISH and all output could be flushed.
770 gzflush should be called only when strictly necessary because it can
771 degrade compression.
774 #ifdef MOZILLA_CLIENT
775 PR_PUBLIC_API(extern int) gzclose (gzFile file);
776 #else
777 extern int EXPORT gzclose OF((gzFile file));
778 #endif
780 Flushes all pending output if necessary, closes the compressed file
781 and deallocates all the (de)compression state. The return value is the zlib
782 error number (see function gzerror below).
785 #ifdef MOZILLA_CLIENT
786 PR_PUBLIC_API(extern const char *) gzerror (gzFile file, int *errnum);
787 #else
788 extern const char * EXPORT gzerror OF((gzFile file, int *errnum));
789 #endif
791 Returns the error message for the last error which occurred on the
792 given compressed file. errnum is set to zlib error number. If an
793 error occurred in the file system and not in the compression library,
794 errnum is set to Z_ERRNO and the application may consult errno
795 to get the exact error code.
798 /* checksum functions */
801 These functions are not related to compression but are exported
802 anyway because they might be useful in applications using the
803 compression library.
806 #ifdef MOZILLA_CLIENT
807 PR_PUBLIC_API(extern uLong) adler32 (uLong adler, const Bytef *buf, uInt len);
808 #else
809 extern uLong EXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len));
810 #endif
813 Update a running Adler-32 checksum with the bytes buf[0..len-1] and
814 return the updated checksum. If buf is NULL, this function returns
815 the required initial value for the checksum.
816 An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
817 much faster. Usage example:
819 uLong adler = adler32(0L, Z_NULL, 0);
821 while (read_buffer(buffer, length) != EOF) {
822 adler = adler32(adler, buffer, length);
824 if (adler != original_adler) error();
827 #ifdef MOZILLA_CLIENT
828 PR_PUBLIC_API(extern uLong) crc32 (uLong crc, const Bytef *buf, uInt len);
829 #else
830 extern uLong EXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len));
831 #endif
833 Update a running crc with the bytes buf[0..len-1] and return the updated
834 crc. If buf is NULL, this function returns the required initial value
835 for the crc. Pre- and post-conditioning (one's complement) is performed
836 within this function so it shouldn't be done by the application.
837 Usage example:
839 uLong crc = crc32(0L, Z_NULL, 0);
841 while (read_buffer(buffer, length) != EOF) {
842 crc = crc32(crc, buffer, length);
844 if (crc != original_crc) error();
848 /* various hacks, don't look :) */
850 /* deflateInit and inflateInit are macros to allow checking the zlib version
851 * and the compiler's view of z_stream:
853 #ifdef MOZILLA_CLIENT
854 PR_PUBLIC_API(extern int) deflateInit_ (z_streamp strm, int level, const char *version,
855 int stream_size);
856 PR_PUBLIC_API(extern int) inflateInit_ (z_streamp strm, const char *version,
857 int stream_size);
858 PR_PUBLIC_API(extern int) deflateInit2_ (z_streamp strm, int level, int method,
859 int windowBits, int memLevel, int strategy,
860 const char *version, int stream_size);
861 PR_PUBLIC_API(extern int) inflateInit2_ (z_streamp strm, int windowBits,
862 const char *version, int stream_size);
863 #else
864 extern int EXPORT deflateInit_ OF((z_streamp strm, int level, const char *version,
865 int stream_size));
866 extern int EXPORT inflateInit_ OF((z_streamp strm, const char *version,
867 int stream_size));
868 extern int EXPORT deflateInit2_ OF((z_streamp strm, int level, int method,
869 int windowBits, int memLevel, int strategy,
870 const char *version, int stream_size));
871 extern int EXPORT inflateInit2_ OF((z_streamp strm, int windowBits,
872 const char *version, int stream_size));
873 #endif /* MOZILLA_CLIENT */
876 #define deflateInit(strm, level) \
877 deflateInit_((strm), (level), ZLIB_VERSION, sizeof(z_stream))
878 #define inflateInit(strm) \
879 inflateInit_((strm), ZLIB_VERSION, sizeof(z_stream))
880 #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
881 deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
882 (strategy), ZLIB_VERSION, sizeof(z_stream))
883 #define inflateInit2(strm, windowBits) \
884 inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream))
886 #if !defined(_Z_UTIL_H) && !defined(NO_DUMMY_DECL)
887 struct internal_state {int dummy;}; /* hack for buggy compilers */
888 #endif
890 uLongf *get_crc_table OF((void)); /* can be used by asm versions of crc32() */
892 #ifdef __cplusplus
894 #endif
896 #endif /* _ZLIB_H */