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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 "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 | |
5914bf15 | 130 | #define Z_INSERT_ONLY 5 |
d4286ec4 PM |
131 | /* Allowed flush values; see deflate() below for details */ |
132 | ||
133 | #define Z_OK 0 | |
134 | #define Z_STREAM_END 1 | |
135 | #define Z_NEED_DICT 2 | |
136 | #define Z_ERRNO (-1) | |
137 | #define Z_STREAM_ERROR (-2) | |
138 | #define Z_DATA_ERROR (-3) | |
139 | #define Z_MEM_ERROR (-4) | |
140 | #define Z_BUF_ERROR (-5) | |
141 | #define Z_VERSION_ERROR (-6) | |
142 | /* Return codes for the compression/decompression functions. Negative | |
143 | * values are errors, positive values are used for special but normal events. | |
144 | */ | |
145 | ||
146 | #define Z_NO_COMPRESSION 0 | |
147 | #define Z_BEST_SPEED 1 | |
148 | #define Z_BEST_COMPRESSION 9 | |
149 | #define Z_DEFAULT_COMPRESSION (-1) | |
150 | /* compression levels */ | |
151 | ||
152 | #define Z_FILTERED 1 | |
153 | #define Z_HUFFMAN_ONLY 2 | |
154 | #define Z_DEFAULT_STRATEGY 0 | |
155 | /* compression strategy; see deflateInit2() below for details */ | |
156 | ||
157 | #define Z_BINARY 0 | |
158 | #define Z_ASCII 1 | |
159 | #define Z_UNKNOWN 2 | |
160 | /* Possible values of the data_type field */ | |
161 | ||
162 | #define Z_DEFLATED 8 | |
163 | /* The deflate compression method (the only one supported in this version) */ | |
164 | ||
165 | #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */ | |
166 | ||
167 | #define zlib_version zlibVersion() | |
168 | /* for compatibility with versions < 1.0.2 */ | |
169 | ||
170 | /* basic functions */ | |
171 | ||
172 | extern const char * ZEXPORT zlibVersion OF((void)); | |
173 | /* The application can compare zlibVersion and ZLIB_VERSION for consistency. | |
174 | If the first character differs, the library code actually used is | |
175 | not compatible with the zlib.h header file used by the application. | |
176 | This check is automatically made by deflateInit and inflateInit. | |
177 | */ | |
178 | ||
179 | /* | |
180 | extern int ZEXPORT deflateInit OF((z_streamp strm, int level)); | |
181 | ||
182 | Initializes the internal stream state for compression. The fields | |
183 | zalloc, zfree and opaque must be initialized before by the caller. | |
184 | If zalloc and zfree are set to Z_NULL, deflateInit updates them to | |
185 | use default allocation functions. | |
186 | ||
187 | The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9: | |
188 | 1 gives best speed, 9 gives best compression, 0 gives no compression at | |
189 | all (the input data is simply copied a block at a time). | |
190 | Z_DEFAULT_COMPRESSION requests a default compromise between speed and | |
191 | compression (currently equivalent to level 6). | |
192 | ||
193 | deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not | |
194 | enough memory, Z_STREAM_ERROR if level is not a valid compression level, | |
195 | Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible | |
196 | with the version assumed by the caller (ZLIB_VERSION). | |
197 | msg is set to null if there is no error message. deflateInit does not | |
198 | perform any compression: this will be done by deflate(). | |
199 | */ | |
200 | ||
201 | ||
202 | extern int ZEXPORT deflate OF((z_streamp strm, int flush)); | |
203 | /* | |
204 | deflate compresses as much data as possible, and stops when the input | |
205 | buffer becomes empty or the output buffer becomes full. It may introduce some | |
206 | output latency (reading input without producing any output) except when | |
207 | forced to flush. | |
208 | ||
209 | The detailed semantics are as follows. deflate performs one or both of the | |
210 | following actions: | |
211 | ||
212 | - Compress more input starting at next_in and update next_in and avail_in | |
213 | accordingly. If not all input can be processed (because there is not | |
214 | enough room in the output buffer), next_in and avail_in are updated and | |
215 | processing will resume at this point for the next call of deflate(). | |
216 | ||
217 | - Provide more output starting at next_out and update next_out and avail_out | |
218 | accordingly. This action is forced if the parameter flush is non zero. | |
219 | Forcing flush frequently degrades the compression ratio, so this parameter | |
220 | should be set only when necessary (in interactive applications). | |
221 | Some output may be provided even if flush is not set. | |
222 | ||
223 | Before the call of deflate(), the application should ensure that at least | |
224 | one of the actions is possible, by providing more input and/or consuming | |
225 | more output, and updating avail_in or avail_out accordingly; avail_out | |
226 | should never be zero before the call. The application can consume the | |
227 | compressed output when it wants, for example when the output buffer is full | |
228 | (avail_out == 0), or after each call of deflate(). If deflate returns Z_OK | |
229 | and with zero avail_out, it must be called again after making room in the | |
230 | output buffer because there might be more output pending. | |
231 | ||
232 | If the parameter flush is set to Z_SYNC_FLUSH, all pending output is | |
233 | flushed to the output buffer and the output is aligned on a byte boundary, so | |
234 | that the decompressor can get all input data available so far. (In particular | |
235 | avail_in is zero after the call if enough output space has been provided | |
236 | before the call.) Flushing may degrade compression for some compression | |
237 | algorithms and so it should be used only when necessary. | |
238 | ||
239 | If flush is set to Z_FULL_FLUSH, all output is flushed as with | |
240 | Z_SYNC_FLUSH, and the compression state is reset so that decompression can | |
241 | restart from this point if previous compressed data has been damaged or if | |
242 | random access is desired. Using Z_FULL_FLUSH too often can seriously degrade | |
243 | the compression. | |
244 | ||
245 | If deflate returns with avail_out == 0, this function must be called again | |
246 | with the same value of the flush parameter and more output space (updated | |
247 | avail_out), until the flush is complete (deflate returns with non-zero | |
248 | avail_out). | |
249 | ||
250 | If the parameter flush is set to Z_FINISH, pending input is processed, | |
251 | pending output is flushed and deflate returns with Z_STREAM_END if there | |
252 | was enough output space; if deflate returns with Z_OK, this function must be | |
253 | called again with Z_FINISH and more output space (updated avail_out) but no | |
254 | more input data, until it returns with Z_STREAM_END or an error. After | |
255 | deflate has returned Z_STREAM_END, the only possible operations on the | |
256 | stream are deflateReset or deflateEnd. | |
257 | ||
258 | Z_FINISH can be used immediately after deflateInit if all the compression | |
259 | is to be done in a single step. In this case, avail_out must be at least | |
260 | 0.1% larger than avail_in plus 12 bytes. If deflate does not return | |
261 | Z_STREAM_END, then it must be called again as described above. | |
262 | ||
263 | deflate() sets strm->adler to the adler32 checksum of all input read | |
264 | so far (that is, total_in bytes). | |
265 | ||
266 | deflate() may update data_type if it can make a good guess about | |
267 | the input data type (Z_ASCII or Z_BINARY). In doubt, the data is considered | |
268 | binary. This field is only for information purposes and does not affect | |
269 | the compression algorithm in any manner. | |
270 | ||
271 | deflate() returns Z_OK if some progress has been made (more input | |
272 | processed or more output produced), Z_STREAM_END if all input has been | |
273 | consumed and all output has been produced (only when flush is set to | |
274 | Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example | |
275 | if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible. | |
276 | */ | |
277 | ||
278 | ||
279 | extern 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 | extern 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 | extern 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 | extern 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 | extern 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 | extern 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 or deflateInit2, before any call of | |
451 | 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 | extern 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 | extern 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 | extern int ZEXPORT deflateParams OF((z_streamp strm, int level, int strategy)); | |
510 | /* | |
511 | Dynamically update the compression level and compression strategy. The | |
512 | interpretation of level and strategy is as in deflateInit2. This can be | |
513 | used to switch between compression and straight copy of the input data, or | |
514 | to switch to a different kind of input data requiring a different | |
515 | strategy. If the compression level is changed, the input available so far | |
516 | is compressed with the old level (and may be flushed); the new level will | |
517 | take effect only at the next call of deflate(). | |
518 | ||
519 | Before the call of deflateParams, the stream state must be set as for | |
520 | a call of deflate(), since the currently available input may have to | |
521 | be compressed and flushed. In particular, strm->avail_out must be non-zero. | |
522 | ||
523 | deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source | |
524 | stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR | |
525 | if strm->avail_out was zero. | |
526 | */ | |
527 | ||
528 | /* | |
529 | extern int ZEXPORT inflateInit2 OF((z_streamp strm, | |
530 | int windowBits)); | |
531 | ||
532 | This is another version of inflateInit with an extra parameter. The | |
533 | fields next_in, avail_in, zalloc, zfree and opaque must be initialized | |
534 | before by the caller. | |
535 | ||
536 | The windowBits parameter is the base two logarithm of the maximum window | |
537 | size (the size of the history buffer). It should be in the range 8..15 for | |
538 | this version of the library. The default value is 15 if inflateInit is used | |
539 | instead. If a compressed stream with a larger window size is given as | |
540 | input, inflate() will return with the error code Z_DATA_ERROR instead of | |
541 | trying to allocate a larger window. | |
542 | ||
543 | inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough | |
544 | memory, Z_STREAM_ERROR if a parameter is invalid (such as a negative | |
545 | memLevel). msg is set to null if there is no error message. inflateInit2 | |
546 | does not perform any decompression apart from reading the zlib header if | |
547 | present: this will be done by inflate(). (So next_in and avail_in may be | |
548 | modified, but next_out and avail_out are unchanged.) | |
549 | */ | |
550 | ||
551 | extern int ZEXPORT inflateSetDictionary OF((z_streamp strm, | |
552 | const Bytef *dictionary, | |
553 | uInt dictLength)); | |
554 | /* | |
555 | Initializes the decompression dictionary from the given uncompressed byte | |
556 | sequence. This function must be called immediately after a call of inflate | |
557 | if this call returned Z_NEED_DICT. The dictionary chosen by the compressor | |
558 | can be determined from the Adler32 value returned by this call of | |
559 | inflate. The compressor and decompressor must use exactly the same | |
560 | dictionary (see deflateSetDictionary). | |
561 | ||
562 | inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a | |
563 | parameter is invalid (such as NULL dictionary) or the stream state is | |
564 | inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the | |
565 | expected one (incorrect Adler32 value). inflateSetDictionary does not | |
566 | perform any decompression: this will be done by subsequent calls of | |
567 | inflate(). | |
568 | */ | |
569 | ||
570 | extern int ZEXPORT inflateSync OF((z_streamp strm)); | |
571 | /* | |
572 | Skips invalid compressed data until a full flush point (see above the | |
573 | description of deflate with Z_FULL_FLUSH) can be found, or until all | |
574 | available input is skipped. No output is provided. | |
575 | ||
576 | inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR | |
577 | if no more input was provided, Z_DATA_ERROR if no flush point has been found, | |
578 | or Z_STREAM_ERROR if the stream structure was inconsistent. In the success | |
579 | case, the application may save the current current value of total_in which | |
580 | indicates where valid compressed data was found. In the error case, the | |
581 | application may repeatedly call inflateSync, providing more input each time, | |
582 | until success or end of the input data. | |
583 | */ | |
584 | ||
585 | extern int ZEXPORT inflateReset OF((z_streamp strm)); | |
586 | /* | |
587 | This function is equivalent to inflateEnd followed by inflateInit, | |
588 | but does not free and reallocate all the internal decompression state. | |
589 | The stream will keep attributes that may have been set by inflateInit2. | |
590 | ||
591 | inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source | |
592 | stream state was inconsistent (such as zalloc or state being NULL). | |
593 | */ | |
594 | ||
595 | ||
596 | /* utility functions */ | |
597 | ||
598 | /* | |
599 | The following utility functions are implemented on top of the | |
600 | basic stream-oriented functions. To simplify the interface, some | |
601 | default options are assumed (compression level and memory usage, | |
602 | standard memory allocation functions). The source code of these | |
603 | utility functions can easily be modified if you need special options. | |
604 | */ | |
605 | ||
606 | extern int ZEXPORT compress OF((Bytef *dest, uLongf *destLen, | |
607 | const Bytef *source, uLong sourceLen)); | |
608 | /* | |
609 | Compresses the source buffer into the destination buffer. sourceLen is | |
610 | the byte length of the source buffer. Upon entry, destLen is the total | |
611 | size of the destination buffer, which must be at least 0.1% larger than | |
612 | sourceLen plus 12 bytes. Upon exit, destLen is the actual size of the | |
613 | compressed buffer. | |
614 | This function can be used to compress a whole file at once if the | |
615 | input file is mmap'ed. | |
616 | compress returns Z_OK if success, Z_MEM_ERROR if there was not | |
617 | enough memory, Z_BUF_ERROR if there was not enough room in the output | |
618 | buffer. | |
619 | */ | |
620 | ||
621 | extern int ZEXPORT compress2 OF((Bytef *dest, uLongf *destLen, | |
622 | const Bytef *source, uLong sourceLen, | |
623 | int level)); | |
624 | /* | |
625 | Compresses the source buffer into the destination buffer. The level | |
626 | parameter has the same meaning as in deflateInit. sourceLen is the byte | |
627 | length of the source buffer. Upon entry, destLen is the total size of the | |
628 | destination buffer, which must be at least 0.1% larger than sourceLen plus | |
629 | 12 bytes. Upon exit, destLen is the actual size of the compressed buffer. | |
630 | ||
631 | compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough | |
632 | memory, Z_BUF_ERROR if there was not enough room in the output buffer, | |
633 | Z_STREAM_ERROR if the level parameter is invalid. | |
634 | */ | |
635 | ||
636 | extern int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen, | |
637 | const Bytef *source, uLong sourceLen)); | |
638 | /* | |
639 | Decompresses the source buffer into the destination buffer. sourceLen is | |
640 | the byte length of the source buffer. Upon entry, destLen is the total | |
641 | size of the destination buffer, which must be large enough to hold the | |
642 | entire uncompressed data. (The size of the uncompressed data must have | |
643 | been saved previously by the compressor and transmitted to the decompressor | |
644 | by some mechanism outside the scope of this compression library.) | |
645 | Upon exit, destLen is the actual size of the compressed buffer. | |
646 | This function can be used to decompress a whole file at once if the | |
647 | input file is mmap'ed. | |
648 | ||
649 | uncompress returns Z_OK if success, Z_MEM_ERROR if there was not | |
650 | enough memory, Z_BUF_ERROR if there was not enough room in the output | |
651 | buffer, or Z_DATA_ERROR if the input data was corrupted. | |
652 | */ | |
653 | ||
654 | ||
655 | typedef voidp gzFile; | |
656 | ||
657 | extern gzFile ZEXPORT gzopen OF((const char *path, const char *mode)); | |
658 | /* | |
659 | Opens a gzip (.gz) file for reading or writing. The mode parameter | |
660 | is as in fopen ("rb" or "wb") but can also include a compression level | |
661 | ("wb9") or a strategy: 'f' for filtered data as in "wb6f", 'h' for | |
662 | Huffman only compression as in "wb1h". (See the description | |
663 | of deflateInit2 for more information about the strategy parameter.) | |
664 | ||
665 | gzopen can be used to read a file which is not in gzip format; in this | |
666 | case gzread will directly read from the file without decompression. | |
667 | ||
668 | gzopen returns NULL if the file could not be opened or if there was | |
669 | insufficient memory to allocate the (de)compression state; errno | |
670 | can be checked to distinguish the two cases (if errno is zero, the | |
671 | zlib error is Z_MEM_ERROR). */ | |
672 | ||
673 | extern gzFile ZEXPORT gzdopen OF((int fd, const char *mode)); | |
674 | /* | |
675 | gzdopen() associates a gzFile with the file descriptor fd. File | |
676 | descriptors are obtained from calls like open, dup, creat, pipe or | |
677 | fileno (in the file has been previously opened with fopen). | |
678 | The mode parameter is as in gzopen. | |
679 | The next call of gzclose on the returned gzFile will also close the | |
680 | file descriptor fd, just like fclose(fdopen(fd), mode) closes the file | |
681 | descriptor fd. If you want to keep fd open, use gzdopen(dup(fd), mode). | |
682 | gzdopen returns NULL if there was insufficient memory to allocate | |
683 | the (de)compression state. | |
684 | */ | |
685 | ||
686 | extern int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy)); | |
687 | /* | |
688 | Dynamically update the compression level or strategy. See the description | |
689 | of deflateInit2 for the meaning of these parameters. | |
690 | gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not | |
691 | opened for writing. | |
692 | */ | |
693 | ||
694 | extern int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len)); | |
695 | /* | |
696 | Reads the given number of uncompressed bytes from the compressed file. | |
697 | If the input file was not in gzip format, gzread copies the given number | |
698 | of bytes into the buffer. | |
699 | gzread returns the number of uncompressed bytes actually read (0 for | |
700 | end of file, -1 for error). */ | |
701 | ||
702 | extern int ZEXPORT gzwrite OF((gzFile file, const voidp buf, unsigned len)); | |
703 | /* | |
704 | Writes the given number of uncompressed bytes into the compressed file. | |
705 | gzwrite returns the number of uncompressed bytes actually written | |
706 | (0 in case of error). | |
707 | */ | |
708 | ||
709 | extern int ZEXPORTVA gzprintf OF((gzFile file, const char *format, ...)); | |
710 | /* | |
711 | Converts, formats, and writes the args to the compressed file under | |
712 | control of the format string, as in fprintf. gzprintf returns the number of | |
713 | uncompressed bytes actually written (0 in case of error). | |
714 | */ | |
715 | ||
716 | extern int ZEXPORT gzputs OF((gzFile file, const char *s)); | |
717 | /* | |
718 | Writes the given null-terminated string to the compressed file, excluding | |
719 | the terminating null character. | |
720 | gzputs returns the number of characters written, or -1 in case of error. | |
721 | */ | |
722 | ||
723 | extern char * ZEXPORT gzgets OF((gzFile file, char *buf, int len)); | |
724 | /* | |
725 | Reads bytes from the compressed file until len-1 characters are read, or | |
726 | a newline character is read and transferred to buf, or an end-of-file | |
727 | condition is encountered. The string is then terminated with a null | |
728 | character. | |
729 | gzgets returns buf, or Z_NULL in case of error. | |
730 | */ | |
731 | ||
732 | extern int ZEXPORT gzputc OF((gzFile file, int c)); | |
733 | /* | |
734 | Writes c, converted to an unsigned char, into the compressed file. | |
735 | gzputc returns the value that was written, or -1 in case of error. | |
736 | */ | |
737 | ||
738 | extern int ZEXPORT gzgetc OF((gzFile file)); | |
739 | /* | |
740 | Reads one byte from the compressed file. gzgetc returns this byte | |
741 | or -1 in case of end of file or error. | |
742 | */ | |
743 | ||
744 | extern int ZEXPORT gzflush OF((gzFile file, int flush)); | |
745 | /* | |
746 | Flushes all pending output into the compressed file. The parameter | |
747 | flush is as in the deflate() function. The return value is the zlib | |
748 | error number (see function gzerror below). gzflush returns Z_OK if | |
749 | the flush parameter is Z_FINISH and all output could be flushed. | |
750 | gzflush should be called only when strictly necessary because it can | |
751 | degrade compression. | |
752 | */ | |
753 | ||
754 | extern z_off_t ZEXPORT gzseek OF((gzFile file, z_off_t offset, int whence)); | |
755 | /* | |
756 | Sets the starting position for the next gzread or gzwrite on the given | |
757 | compressed file. The offset represents a number of bytes in the | |
758 | uncompressed data stream. The whence parameter is defined as in lseek(2); | |
759 | the value SEEK_END is not supported. | |
760 | If the file is opened for reading, this function is emulated but can be | |
761 | extremely slow. If the file is opened for writing, only forward seeks are | |
762 | supported; gzseek then compresses a sequence of zeroes up to the new | |
763 | starting position. | |
764 | ||
765 | gzseek returns the resulting offset location as measured in bytes from | |
766 | the beginning of the uncompressed stream, or -1 in case of error, in | |
767 | particular if the file is opened for writing and the new starting position | |
768 | would be before the current position. | |
769 | */ | |
770 | ||
771 | extern int ZEXPORT gzrewind OF((gzFile file)); | |
772 | /* | |
773 | Rewinds the given file. This function is supported only for reading. | |
774 | ||
775 | gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET) | |
776 | */ | |
777 | ||
778 | extern z_off_t ZEXPORT gztell OF((gzFile file)); | |
779 | /* | |
780 | Returns the starting position for the next gzread or gzwrite on the | |
781 | given compressed file. This position represents a number of bytes in the | |
782 | uncompressed data stream. | |
783 | ||
784 | gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR) | |
785 | */ | |
786 | ||
787 | extern int ZEXPORT gzeof OF((gzFile file)); | |
788 | /* | |
789 | Returns 1 when EOF has previously been detected reading the given | |
790 | input stream, otherwise zero. | |
791 | */ | |
792 | ||
793 | extern int ZEXPORT gzclose OF((gzFile file)); | |
794 | /* | |
795 | Flushes all pending output if necessary, closes the compressed file | |
796 | and deallocates all the (de)compression state. The return value is the zlib | |
797 | error number (see function gzerror below). | |
798 | */ | |
799 | ||
800 | extern const char * ZEXPORT gzerror OF((gzFile file, int *errnum)); | |
801 | /* | |
802 | Returns the error message for the last error which occurred on the | |
803 | given compressed file. errnum is set to zlib error number. If an | |
804 | error occurred in the file system and not in the compression library, | |
805 | errnum is set to Z_ERRNO and the application may consult errno | |
806 | to get the exact error code. | |
807 | */ | |
808 | ||
809 | /* checksum functions */ | |
810 | ||
811 | /* | |
812 | These functions are not related to compression but are exported | |
813 | anyway because they might be useful in applications using the | |
814 | compression library. | |
815 | */ | |
816 | ||
817 | extern uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len)); | |
818 | ||
819 | /* | |
820 | Update a running Adler-32 checksum with the bytes buf[0..len-1] and | |
821 | return the updated checksum. If buf is NULL, this function returns | |
822 | the required initial value for the checksum. | |
823 | An Adler-32 checksum is almost as reliable as a CRC32 but can be computed | |
824 | much faster. Usage example: | |
825 | ||
826 | uLong adler = adler32(0L, Z_NULL, 0); | |
827 | ||
828 | while (read_buffer(buffer, length) != EOF) { | |
829 | adler = adler32(adler, buffer, length); | |
830 | } | |
831 | if (adler != original_adler) error(); | |
832 | */ | |
833 | ||
834 | extern uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len)); | |
835 | /* | |
836 | Update a running crc with the bytes buf[0..len-1] and return the updated | |
837 | crc. If buf is NULL, this function returns the required initial value | |
838 | for the crc. Pre- and post-conditioning (one's complement) is performed | |
839 | within this function so it shouldn't be done by the application. | |
840 | Usage example: | |
841 | ||
842 | uLong crc = crc32(0L, Z_NULL, 0); | |
843 | ||
844 | while (read_buffer(buffer, length) != EOF) { | |
845 | crc = crc32(crc, buffer, length); | |
846 | } | |
847 | if (crc != original_crc) error(); | |
848 | */ | |
849 | ||
850 | ||
851 | /* various hacks, don't look :) */ | |
852 | ||
853 | /* deflateInit and inflateInit are macros to allow checking the zlib version | |
854 | * and the compiler's view of z_stream: | |
855 | */ | |
856 | extern int ZEXPORT deflateInit_ OF((z_streamp strm, int level, | |
857 | const char *version, int stream_size)); | |
858 | extern int ZEXPORT inflateInit_ OF((z_streamp strm, | |
859 | const char *version, int stream_size)); | |
860 | extern int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method, | |
861 | int windowBits, int memLevel, | |
862 | int strategy, const char *version, | |
863 | int stream_size)); | |
864 | extern int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits, | |
865 | const char *version, int stream_size)); | |
866 | #define deflateInit(strm, level) \ | |
867 | deflateInit_((strm), (level), ZLIB_VERSION, sizeof(z_stream)) | |
868 | #define inflateInit(strm) \ | |
869 | inflateInit_((strm), ZLIB_VERSION, sizeof(z_stream)) | |
870 | #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \ | |
871 | deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\ | |
872 | (strategy), ZLIB_VERSION, sizeof(z_stream)) | |
873 | #define inflateInit2(strm, windowBits) \ | |
874 | inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream)) | |
875 | ||
876 | ||
877 | #if !defined(_Z_UTIL_H) && !defined(NO_DUMMY_DECL) | |
878 | struct internal_state {int dummy;}; /* hack for buggy compilers */ | |
879 | #endif | |
880 | ||
881 | extern const char * ZEXPORT zError OF((int err)); | |
882 | extern int ZEXPORT inflateSyncPoint OF((z_streamp z)); | |
883 | extern const uLongf * ZEXPORT get_crc_table OF((void)); | |
884 | ||
885 | #ifdef __cplusplus | |
886 | } | |
887 | #endif | |
888 | ||
889 | #endif /* _ZLIB_H */ |