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1 | /* zlib.h -- interface of the 'zlib' general purpose compression library |
2 | version 1.1.4, March 11th, 2002 |
3 | |
4 | Copyright (C) 1995-2002 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 "1.1.4" |
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 */ |