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c45f211e | 1 | /* zlib.h -- interface of the 'zlib' general purpose compression library |
e1b56469 | 2 | version 1.1.4, March 11th, 2002 |
c45f211e | 3 | |
e1b56469 | 4 | Copyright (C) 1995-2002 Jean-loup Gailly and Mark Adler |
c45f211e TT |
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 | ||
e1b56469 | 40 | #define ZLIB_VERSION "1.1.4" |
c45f211e TT |
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 */ |