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1 | /* zlib.h -- interface of the 'zlib' general purpose compression library | |
2 | version 1.2.1, November 17th, 2003 | |
3 | ||
4 | Copyright (C) 1995-2003 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 http://www.ietf.org/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 "1.2.1" | |
41 | #define ZLIB_VERNUM 0x1210 | |
42 | ||
43 | /* | |
44 | The 'zlib' compression library provides in-memory compression and | |
45 | decompression functions, including integrity checks of the uncompressed | |
46 | data. This version of the library supports only one compression method | |
47 | (deflation) but other algorithms will be added later and will have the same | |
48 | stream interface. | |
49 | ||
50 | Compression can be done in a single step if the buffers are large | |
51 | enough (for example if an input file is mmap'ed), or can be done by | |
52 | repeated calls of the compression function. In the latter case, the | |
53 | application must provide more input and/or consume the output | |
54 | (providing more output space) before each call. | |
55 | ||
56 | The compressed data format used by the in-memory functions is the zlib | |
57 | format, which is a zlib wrapper documented in RFC 1950, wrapped around a | |
58 | deflate stream, which is itself documented in RFC 1951. | |
59 | ||
60 | The library also supports reading and writing files in gzip (.gz) format | |
61 | with an interface similar to that of stdio using the functions that start | |
62 | with "gz". The gzip format is different from the zlib format. gzip is a | |
63 | gzip wrapper, documented in RFC 1952, wrapped around a deflate stream. | |
64 | ||
65 | The zlib format was designed to be compact and fast for use in memory | |
66 | and on communications channels. The gzip format was designed for single- | |
67 | file compression on file systems, has a larger header than zlib to maintain | |
68 | directory information, and uses a different, slower check method than zlib. | |
69 | ||
70 | This library does not provide any functions to write gzip files in memory. | |
71 | However such functions could be easily written using zlib's deflate function, | |
72 | the documentation in the gzip RFC, and the examples in gzio.c. | |
73 | ||
74 | The library does not install any signal handler. The decoder checks | |
75 | the consistency of the compressed data, so the library should never | |
76 | crash even in case of corrupted input. | |
77 | */ | |
78 | ||
79 | typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size)); | |
80 | typedef void (*free_func) OF((voidpf opaque, voidpf address)); | |
81 | ||
82 | struct internal_state; | |
83 | ||
84 | typedef struct z_stream_s { | |
85 | Bytef *next_in; /* next input byte */ | |
86 | uInt avail_in; /* number of bytes available at next_in */ | |
87 | uLong total_in; /* total nb of input bytes read so far */ | |
88 | ||
89 | Bytef *next_out; /* next output byte should be put there */ | |
90 | uInt avail_out; /* remaining free space at next_out */ | |
91 | uLong total_out; /* total nb of bytes output so far */ | |
92 | ||
93 | char *msg; /* last error message, NULL if no error */ | |
94 | struct internal_state FAR *state; /* not visible by applications */ | |
95 | ||
96 | alloc_func zalloc; /* used to allocate the internal state */ | |
97 | free_func zfree; /* used to free the internal state */ | |
98 | voidpf opaque; /* private data object passed to zalloc and zfree */ | |
99 | ||
100 | int data_type; /* best guess about the data type: ascii or binary */ | |
101 | uLong adler; /* adler32 value of the uncompressed data */ | |
102 | uLong reserved; /* reserved for future use */ | |
103 | } z_stream; | |
104 | ||
105 | typedef z_stream FAR *z_streamp; | |
106 | ||
107 | /* | |
108 | The application must update next_in and avail_in when avail_in has | |
109 | dropped to zero. It must update next_out and avail_out when avail_out | |
110 | has dropped to zero. The application must initialize zalloc, zfree and | |
111 | opaque before calling the init function. All other fields are set by the | |
112 | compression library and must not be updated by the application. | |
113 | ||
114 | The opaque value provided by the application will be passed as the first | |
115 | parameter for calls of zalloc and zfree. This can be useful for custom | |
116 | memory management. The compression library attaches no meaning to the | |
117 | opaque value. | |
118 | ||
119 | zalloc must return Z_NULL if there is not enough memory for the object. | |
120 | If zlib is used in a multi-threaded application, zalloc and zfree must be | |
121 | thread safe. | |
122 | ||
123 | On 16-bit systems, the functions zalloc and zfree must be able to allocate | |
124 | exactly 65536 bytes, but will not be required to allocate more than this | |
125 | if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, | |
126 | pointers returned by zalloc for objects of exactly 65536 bytes *must* | |
127 | have their offset normalized to zero. The default allocation function | |
128 | provided by this library ensures this (see zutil.c). To reduce memory | |
129 | requirements and avoid any allocation of 64K objects, at the expense of | |
130 | compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h). | |
131 | ||
132 | The fields total_in and total_out can be used for statistics or | |
133 | progress reports. After compression, total_in holds the total size of | |
134 | the uncompressed data and may be saved for use in the decompressor | |
135 | (particularly if the decompressor wants to decompress everything in | |
136 | a single step). | |
137 | */ | |
138 | ||
139 | /* constants */ | |
140 | ||
141 | #define Z_NO_FLUSH 0 | |
142 | #define Z_PARTIAL_FLUSH 1 /* will be removed, use Z_SYNC_FLUSH instead */ | |
143 | #define Z_SYNC_FLUSH 2 | |
144 | #define Z_FULL_FLUSH 3 | |
145 | #define Z_FINISH 4 | |
146 | #define Z_BLOCK 5 | |
147 | /* Allowed flush values; see deflate() and inflate() below for details */ | |
148 | ||
149 | #define Z_OK 0 | |
150 | #define Z_STREAM_END 1 | |
151 | #define Z_NEED_DICT 2 | |
152 | #define Z_ERRNO (-1) | |
153 | #define Z_STREAM_ERROR (-2) | |
154 | #define Z_DATA_ERROR (-3) | |
155 | #define Z_MEM_ERROR (-4) | |
156 | #define Z_BUF_ERROR (-5) | |
157 | #define Z_VERSION_ERROR (-6) | |
158 | /* Return codes for the compression/decompression functions. Negative | |
159 | * values are errors, positive values are used for special but normal events. | |
160 | */ | |
161 | ||
162 | #define Z_NO_COMPRESSION 0 | |
163 | #define Z_BEST_SPEED 1 | |
164 | #define Z_BEST_COMPRESSION 9 | |
165 | #define Z_DEFAULT_COMPRESSION (-1) | |
166 | /* compression levels */ | |
167 | ||
168 | #define Z_FILTERED 1 | |
169 | #define Z_HUFFMAN_ONLY 2 | |
170 | #define Z_RLE 3 | |
171 | #define Z_DEFAULT_STRATEGY 0 | |
172 | /* compression strategy; see deflateInit2() below for details */ | |
173 | ||
174 | #define Z_BINARY 0 | |
175 | #define Z_ASCII 1 | |
176 | #define Z_UNKNOWN 2 | |
177 | /* Possible values of the data_type field (though see inflate()) */ | |
178 | ||
179 | #define Z_DEFLATED 8 | |
180 | /* The deflate compression method (the only one supported in this version) */ | |
181 | ||
182 | #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */ | |
183 | ||
184 | #define zlib_version zlibVersion() | |
185 | /* for compatibility with versions < 1.0.2 */ | |
186 | ||
187 | /* basic functions */ | |
188 | ||
189 | ZEXTERN const char * ZEXPORT zlibVersion OF((void)); | |
190 | /* The application can compare zlibVersion and ZLIB_VERSION for consistency. | |
191 | If the first character differs, the library code actually used is | |
192 | not compatible with the zlib.h header file used by the application. | |
193 | This check is automatically made by deflateInit and inflateInit. | |
194 | */ | |
195 | ||
196 | /* | |
197 | ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level)); | |
198 | ||
199 | Initializes the internal stream state for compression. The fields | |
200 | zalloc, zfree and opaque must be initialized before by the caller. | |
201 | If zalloc and zfree are set to Z_NULL, deflateInit updates them to | |
202 | use default allocation functions. | |
203 | ||
204 | The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9: | |
205 | 1 gives best speed, 9 gives best compression, 0 gives no compression at | |
206 | all (the input data is simply copied a block at a time). | |
207 | Z_DEFAULT_COMPRESSION requests a default compromise between speed and | |
208 | compression (currently equivalent to level 6). | |
209 | ||
210 | deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not | |
211 | enough memory, Z_STREAM_ERROR if level is not a valid compression level, | |
212 | Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible | |
213 | with the version assumed by the caller (ZLIB_VERSION). | |
214 | msg is set to null if there is no error message. deflateInit does not | |
215 | perform any compression: this will be done by deflate(). | |
216 | */ | |
217 | ||
218 | ||
219 | ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush)); | |
220 | /* | |
221 | deflate compresses as much data as possible, and stops when the input | |
222 | buffer becomes empty or the output buffer becomes full. It may introduce some | |
223 | output latency (reading input without producing any output) except when | |
224 | forced to flush. | |
225 | ||
226 | The detailed semantics are as follows. deflate performs one or both of the | |
227 | following actions: | |
228 | ||
229 | - Compress more input starting at next_in and update next_in and avail_in | |
230 | accordingly. If not all input can be processed (because there is not | |
231 | enough room in the output buffer), next_in and avail_in are updated and | |
232 | processing will resume at this point for the next call of deflate(). | |
233 | ||
234 | - Provide more output starting at next_out and update next_out and avail_out | |
235 | accordingly. This action is forced if the parameter flush is non zero. | |
236 | Forcing flush frequently degrades the compression ratio, so this parameter | |
237 | should be set only when necessary (in interactive applications). | |
238 | Some output may be provided even if flush is not set. | |
239 | ||
240 | Before the call of deflate(), the application should ensure that at least | |
241 | one of the actions is possible, by providing more input and/or consuming | |
242 | more output, and updating avail_in or avail_out accordingly; avail_out | |
243 | should never be zero before the call. The application can consume the | |
244 | compressed output when it wants, for example when the output buffer is full | |
245 | (avail_out == 0), or after each call of deflate(). If deflate returns Z_OK | |
246 | and with zero avail_out, it must be called again after making room in the | |
247 | output buffer because there might be more output pending. | |
248 | ||
249 | If the parameter flush is set to Z_SYNC_FLUSH, all pending output is | |
250 | flushed to the output buffer and the output is aligned on a byte boundary, so | |
251 | that the decompressor can get all input data available so far. (In particular | |
252 | avail_in is zero after the call if enough output space has been provided | |
253 | before the call.) Flushing may degrade compression for some compression | |
254 | algorithms and so it should be used only when necessary. | |
255 | ||
256 | If flush is set to Z_FULL_FLUSH, all output is flushed as with | |
257 | Z_SYNC_FLUSH, and the compression state is reset so that decompression can | |
258 | restart from this point if previous compressed data has been damaged or if | |
259 | random access is desired. Using Z_FULL_FLUSH too often can seriously degrade | |
260 | the compression. | |
261 | ||
262 | If deflate returns with avail_out == 0, this function must be called again | |
263 | with the same value of the flush parameter and more output space (updated | |
264 | avail_out), until the flush is complete (deflate returns with non-zero | |
265 | avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that | |
266 | avail_out is greater than six to avoid repeated flush markers due to | |
267 | avail_out == 0 on return. | |
268 | ||
269 | If the parameter flush is set to Z_FINISH, pending input is processed, | |
270 | pending output is flushed and deflate returns with Z_STREAM_END if there | |
271 | was enough output space; if deflate returns with Z_OK, this function must be | |
272 | called again with Z_FINISH and more output space (updated avail_out) but no | |
273 | more input data, until it returns with Z_STREAM_END or an error. After | |
274 | deflate has returned Z_STREAM_END, the only possible operations on the | |
275 | stream are deflateReset or deflateEnd. | |
276 | ||
277 | Z_FINISH can be used immediately after deflateInit if all the compression | |
278 | is to be done in a single step. In this case, avail_out must be at least | |
279 | the value returned by deflateBound (see below). If deflate does not return | |
280 | Z_STREAM_END, then it must be called again as described above. | |
281 | ||
282 | deflate() sets strm->adler to the adler32 checksum of all input read | |
283 | so far (that is, total_in bytes). | |
284 | ||
285 | deflate() may update data_type if it can make a good guess about | |
286 | the input data type (Z_ASCII or Z_BINARY). In doubt, the data is considered | |
287 | binary. This field is only for information purposes and does not affect | |
288 | the compression algorithm in any manner. | |
289 | ||
290 | deflate() returns Z_OK if some progress has been made (more input | |
291 | processed or more output produced), Z_STREAM_END if all input has been | |
292 | consumed and all output has been produced (only when flush is set to | |
293 | Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example | |
294 | if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible | |
295 | (for example avail_in or avail_out was zero). Note that Z_BUF_ERROR is not | |
296 | fatal, and deflate() can be called again with more input and more output | |
297 | space to continue compressing. | |
298 | */ | |
299 | ||
300 | ||
301 | ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm)); | |
302 | /* | |
303 | All dynamically allocated data structures for this stream are freed. | |
304 | This function discards any unprocessed input and does not flush any | |
305 | pending output. | |
306 | ||
307 | deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the | |
308 | stream state was inconsistent, Z_DATA_ERROR if the stream was freed | |
309 | prematurely (some input or output was discarded). In the error case, | |
310 | msg may be set but then points to a static string (which must not be | |
311 | deallocated). | |
312 | */ | |
313 | ||
314 | ||
315 | /* | |
316 | ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm)); | |
317 | ||
318 | Initializes the internal stream state for decompression. The fields | |
319 | next_in, avail_in, zalloc, zfree and opaque must be initialized before by | |
320 | the caller. If next_in is not Z_NULL and avail_in is large enough (the exact | |
321 | value depends on the compression method), inflateInit determines the | |
322 | compression method from the zlib header and allocates all data structures | |
323 | accordingly; otherwise the allocation will be deferred to the first call of | |
324 | inflate. If zalloc and zfree are set to Z_NULL, inflateInit updates them to | |
325 | use default allocation functions. | |
326 | ||
327 | inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough | |
328 | memory, Z_VERSION_ERROR if the zlib library version is incompatible with the | |
329 | version assumed by the caller. msg is set to null if there is no error | |
330 | message. inflateInit does not perform any decompression apart from reading | |
331 | the zlib header if present: this will be done by inflate(). (So next_in and | |
332 | avail_in may be modified, but next_out and avail_out are unchanged.) | |
333 | */ | |
334 | ||
335 | ||
336 | ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush)); | |
337 | /* | |
338 | inflate decompresses as much data as possible, and stops when the input | |
339 | buffer becomes empty or the output buffer becomes full. It may introduce | |
340 | some output latency (reading input without producing any output) except when | |
341 | forced to flush. | |
342 | ||
343 | The detailed semantics are as follows. inflate performs one or both of the | |
344 | following actions: | |
345 | ||
346 | - Decompress more input starting at next_in and update next_in and avail_in | |
347 | accordingly. If not all input can be processed (because there is not | |
348 | enough room in the output buffer), next_in is updated and processing | |
349 | will resume at this point for the next call of inflate(). | |
350 | ||
351 | - Provide more output starting at next_out and update next_out and avail_out | |
352 | accordingly. inflate() provides as much output as possible, until there | |
353 | is no more input data or no more space in the output buffer (see below | |
354 | about the flush parameter). | |
355 | ||
356 | Before the call of inflate(), the application should ensure that at least | |
357 | one of the actions is possible, by providing more input and/or consuming | |
358 | more output, and updating the next_* and avail_* values accordingly. | |
359 | The application can consume the uncompressed output when it wants, for | |
360 | example when the output buffer is full (avail_out == 0), or after each | |
361 | call of inflate(). If inflate returns Z_OK and with zero avail_out, it | |
362 | must be called again after making room in the output buffer because there | |
363 | might be more output pending. | |
364 | ||
365 | The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, | |
366 | Z_FINISH, or Z_BLOCK. Z_SYNC_FLUSH requests that inflate() flush as much | |
367 | output as possible to the output buffer. Z_BLOCK requests that inflate() stop | |
368 | if and when it get to the next deflate block boundary. When decoding the zlib | |
369 | or gzip format, this will cause inflate() to return immediately after the | |
370 | header and before the first block. When doing a raw inflate, inflate() will | |
371 | go ahead and process the first block, and will return when it gets to the end | |
372 | of that block, or when it runs out of data. | |
373 | ||
374 | The Z_BLOCK option assists in appending to or combining deflate streams. | |
375 | Also to assist in this, on return inflate() will set strm->data_type to the | |
376 | number of unused bits in the last byte taken from strm->next_in, plus 64 | |
377 | if inflate() is currently decoding the last block in the deflate stream, | |
378 | plus 128 if inflate() returned immediately after decoding an end-of-block | |
379 | code or decoding the complete header up to just before the first byte of the | |
380 | deflate stream. The end-of-block will not be indicated until all of the | |
381 | uncompressed data from that block has been written to strm->next_out. The | |
382 | number of unused bits may in general be greater than seven, except when | |
383 | bit 7 of data_type is set, in which case the number of unused bits will be | |
384 | less than eight. | |
385 | ||
386 | inflate() should normally be called until it returns Z_STREAM_END or an | |
387 | error. However if all decompression is to be performed in a single step | |
388 | (a single call of inflate), the parameter flush should be set to | |
389 | Z_FINISH. In this case all pending input is processed and all pending | |
390 | output is flushed; avail_out must be large enough to hold all the | |
391 | uncompressed data. (The size of the uncompressed data may have been saved | |
392 | by the compressor for this purpose.) The next operation on this stream must | |
393 | be inflateEnd to deallocate the decompression state. The use of Z_FINISH | |
394 | is never required, but can be used to inform inflate that a faster approach | |
395 | may be used for the single inflate() call. | |
396 | ||
397 | In this implementation, inflate() always flushes as much output as | |
398 | possible to the output buffer, and always uses the faster approach on the | |
399 | first call. So the only effect of the flush parameter in this implementation | |
400 | is on the return value of inflate(), as noted below, or when it returns early | |
401 | because Z_BLOCK is used. | |
402 | ||
403 | If a preset dictionary is needed after this call (see inflateSetDictionary | |
404 | below), inflate sets strm-adler to the adler32 checksum of the dictionary | |
405 | chosen by the compressor and returns Z_NEED_DICT; otherwise it sets | |
406 | strm->adler to the adler32 checksum of all output produced so far (that is, | |
407 | total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described | |
408 | below. At the end of the stream, inflate() checks that its computed adler32 | |
409 | checksum is equal to that saved by the compressor and returns Z_STREAM_END | |
410 | only if the checksum is correct. | |
411 | ||
412 | inflate() will decompress and check either zlib-wrapped or gzip-wrapped | |
413 | deflate data. The header type is detected automatically. Any information | |
414 | contained in the gzip header is not retained, so applications that need that | |
415 | information should instead use raw inflate, see inflateInit2() below, or | |
416 | inflateBack() and perform their own processing of the gzip header and | |
417 | trailer. | |
418 | ||
419 | inflate() returns Z_OK if some progress has been made (more input processed | |
420 | or more output produced), Z_STREAM_END if the end of the compressed data has | |
421 | been reached and all uncompressed output has been produced, Z_NEED_DICT if a | |
422 | preset dictionary is needed at this point, Z_DATA_ERROR if the input data was | |
423 | corrupted (input stream not conforming to the zlib format or incorrect check | |
424 | value), Z_STREAM_ERROR if the stream structure was inconsistent (for example | |
425 | if next_in or next_out was NULL), Z_MEM_ERROR if there was not enough memory, | |
426 | Z_BUF_ERROR if no progress is possible or if there was not enough room in the | |
427 | output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and | |
428 | inflate() can be called again with more input and more output space to | |
429 | continue decompressing. If Z_DATA_ERROR is returned, the application may then | |
430 | call inflateSync() to look for a good compression block if a partial recovery | |
431 | of the data is desired. | |
432 | */ | |
433 | ||
434 | ||
435 | ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm)); | |
436 | /* | |
437 | All dynamically allocated data structures for this stream are freed. | |
438 | This function discards any unprocessed input and does not flush any | |
439 | pending output. | |
440 | ||
441 | inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state | |
442 | was inconsistent. In the error case, msg may be set but then points to a | |
443 | static string (which must not be deallocated). | |
444 | */ | |
445 | ||
446 | /* Advanced functions */ | |
447 | ||
448 | /* | |
449 | The following functions are needed only in some special applications. | |
450 | */ | |
451 | ||
452 | /* | |
453 | ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm, | |
454 | int level, | |
455 | int method, | |
456 | int windowBits, | |
457 | int memLevel, | |
458 | int strategy)); | |
459 | ||
460 | This is another version of deflateInit with more compression options. The | |
461 | fields next_in, zalloc, zfree and opaque must be initialized before by | |
462 | the caller. | |
463 | ||
464 | The method parameter is the compression method. It must be Z_DEFLATED in | |
465 | this version of the library. | |
466 | ||
467 | The windowBits parameter is the base two logarithm of the window size | |
468 | (the size of the history buffer). It should be in the range 8..15 for this | |
469 | version of the library. Larger values of this parameter result in better | |
470 | compression at the expense of memory usage. The default value is 15 if | |
471 | deflateInit is used instead. | |
472 | ||
473 | windowBits can also be -8..-15 for raw deflate. In this case, -windowBits | |
474 | determines the window size. deflate() will then generate raw deflate data | |
475 | with no zlib header or trailer, and will not compute an adler32 check value. | |
476 | ||
477 | windowBits can also be greater than 15 for optional gzip encoding. Add | |
478 | 16 to windowBits to write a simple gzip header and trailer around the | |
479 | compressed data instead of a zlib wrapper. The gzip header will have no | |
480 | file name, no extra data, no comment, no modification time (set to zero), | |
481 | no header crc, and the operating system will be set to 255 (unknown). | |
482 | ||
483 | The memLevel parameter specifies how much memory should be allocated | |
484 | for the internal compression state. memLevel=1 uses minimum memory but | |
485 | is slow and reduces compression ratio; memLevel=9 uses maximum memory | |
486 | for optimal speed. The default value is 8. See zconf.h for total memory | |
487 | usage as a function of windowBits and memLevel. | |
488 | ||
489 | The strategy parameter is used to tune the compression algorithm. Use the | |
490 | value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a | |
491 | filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no | |
492 | string match), or Z_RLE to limit match distances to one (run-length | |
493 | encoding). Filtered data consists mostly of small values with a somewhat | |
494 | random distribution. In this case, the compression algorithm is tuned to | |
495 | compress them better. The effect of Z_FILTERED is to force more Huffman | |
496 | coding and less string matching; it is somewhat intermediate between | |
497 | Z_DEFAULT and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as fast as | |
498 | Z_HUFFMAN_ONLY, but give better compression for PNG image data. The strategy | |
499 | parameter only affects the compression ratio but not the correctness of the | |
500 | compressed output even if it is not set appropriately. | |
501 | ||
502 | deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough | |
503 | memory, Z_STREAM_ERROR if a parameter is invalid (such as an invalid | |
504 | method). msg is set to null if there is no error message. deflateInit2 does | |
505 | not perform any compression: this will be done by deflate(). | |
506 | */ | |
507 | ||
508 | ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm, | |
509 | const Bytef *dictionary, | |
510 | uInt dictLength)); | |
511 | /* | |
512 | Initializes the compression dictionary from the given byte sequence | |
513 | without producing any compressed output. This function must be called | |
514 | immediately after deflateInit, deflateInit2 or deflateReset, before any | |
515 | call of deflate. The compressor and decompressor must use exactly the same | |
516 | dictionary (see inflateSetDictionary). | |
517 | ||
518 | The dictionary should consist of strings (byte sequences) that are likely | |
519 | to be encountered later in the data to be compressed, with the most commonly | |
520 | used strings preferably put towards the end of the dictionary. Using a | |
521 | dictionary is most useful when the data to be compressed is short and can be | |
522 | predicted with good accuracy; the data can then be compressed better than | |
523 | with the default empty dictionary. | |
524 | ||
525 | Depending on the size of the compression data structures selected by | |
526 | deflateInit or deflateInit2, a part of the dictionary may in effect be | |
527 | discarded, for example if the dictionary is larger than the window size in | |
528 | deflate or deflate2. Thus the strings most likely to be useful should be | |
529 | put at the end of the dictionary, not at the front. | |
530 | ||
531 | Upon return of this function, strm->adler is set to the adler32 value | |
532 | of the dictionary; the decompressor may later use this value to determine | |
533 | which dictionary has been used by the compressor. (The adler32 value | |
534 | applies to the whole dictionary even if only a subset of the dictionary is | |
535 | actually used by the compressor.) If a raw deflate was requested, then the | |
536 | adler32 value is not computed and strm->adler is not set. | |
537 | ||
538 | deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a | |
539 | parameter is invalid (such as NULL dictionary) or the stream state is | |
540 | inconsistent (for example if deflate has already been called for this stream | |
541 | or if the compression method is bsort). deflateSetDictionary does not | |
542 | perform any compression: this will be done by deflate(). | |
543 | */ | |
544 | ||
545 | ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest, | |
546 | z_streamp source)); | |
547 | /* | |
548 | Sets the destination stream as a complete copy of the source stream. | |
549 | ||
550 | This function can be useful when several compression strategies will be | |
551 | tried, for example when there are several ways of pre-processing the input | |
552 | data with a filter. The streams that will be discarded should then be freed | |
553 | by calling deflateEnd. Note that deflateCopy duplicates the internal | |
554 | compression state which can be quite large, so this strategy is slow and | |
555 | can consume lots of memory. | |
556 | ||
557 | deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not | |
558 | enough memory, Z_STREAM_ERROR if the source stream state was inconsistent | |
559 | (such as zalloc being NULL). msg is left unchanged in both source and | |
560 | destination. | |
561 | */ | |
562 | ||
563 | ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm)); | |
564 | /* | |
565 | This function is equivalent to deflateEnd followed by deflateInit, | |
566 | but does not free and reallocate all the internal compression state. | |
567 | The stream will keep the same compression level and any other attributes | |
568 | that may have been set by deflateInit2. | |
569 | ||
570 | deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source | |
571 | stream state was inconsistent (such as zalloc or state being NULL). | |
572 | */ | |
573 | ||
574 | ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm, | |
575 | int level, | |
576 | int strategy)); | |
577 | /* | |
578 | Dynamically update the compression level and compression strategy. The | |
579 | interpretation of level and strategy is as in deflateInit2. This can be | |
580 | used to switch between compression and straight copy of the input data, or | |
581 | to switch to a different kind of input data requiring a different | |
582 | strategy. If the compression level is changed, the input available so far | |
583 | is compressed with the old level (and may be flushed); the new level will | |
584 | take effect only at the next call of deflate(). | |
585 | ||
586 | Before the call of deflateParams, the stream state must be set as for | |
587 | a call of deflate(), since the currently available input may have to | |
588 | be compressed and flushed. In particular, strm->avail_out must be non-zero. | |
589 | ||
590 | deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source | |
591 | stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR | |
592 | if strm->avail_out was zero. | |
593 | */ | |
594 | ||
595 | ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm, | |
596 | uLong sourceLen)); | |
597 | /* | |
598 | deflateBound() returns an upper bound on the compressed size after | |
599 | deflation of sourceLen bytes. It must be called after deflateInit() | |
600 | or deflateInit2(). This would be used to allocate an output buffer | |
601 | for deflation in a single pass, and so would be called before deflate(). | |
602 | */ | |
603 | ||
604 | ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm, | |
605 | int bits, | |
606 | int value)); | |
607 | /* | |
608 | deflatePrime() inserts bits in the deflate output stream. The intent | |
609 | is that this function is used to start off the deflate output with the | |
610 | bits leftover from a previous deflate stream when appending to it. As such, | |
611 | this function can only be used for raw deflate, and must be used before the | |
612 | first deflate() call after a deflateInit2() or deflateReset(). bits must be | |
613 | less than or equal to 16, and that many of the least significant bits of | |
614 | value will be inserted in the output. | |
615 | ||
616 | deflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source | |
617 | stream state was inconsistent. | |
618 | */ | |
619 | ||
620 | /* | |
621 | ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm, | |
622 | int windowBits)); | |
623 | ||
624 | This is another version of inflateInit with an extra parameter. The | |
625 | fields next_in, avail_in, zalloc, zfree and opaque must be initialized | |
626 | before by the caller. | |
627 | ||
628 | The windowBits parameter is the base two logarithm of the maximum window | |
629 | size (the size of the history buffer). It should be in the range 8..15 for | |
630 | this version of the library. The default value is 15 if inflateInit is used | |
631 | instead. windowBits must be greater than or equal to the windowBits value | |
632 | provided to deflateInit2() while compressing, or it must be equal to 15 if | |
633 | deflateInit2() was not used. If a compressed stream with a larger window | |
634 | size is given as input, inflate() will return with the error code | |
635 | Z_DATA_ERROR instead of trying to allocate a larger window. | |
636 | ||
637 | windowBits can also be -8..-15 for raw inflate. In this case, -windowBits | |
638 | determines the window size. inflate() will then process raw deflate data, | |
639 | not looking for a zlib or gzip header, not generating a check value, and not | |
640 | looking for any check values for comparison at the end of the stream. This | |
641 | is for use with other formats that use the deflate compressed data format | |
642 | such as zip. Those formats provide their own check values. If a custom | |
643 | format is developed using the raw deflate format for compressed data, it is | |
644 | recommended that a check value such as an adler32 or a crc32 be applied to | |
645 | the uncompressed data as is done in the zlib, gzip, and zip formats. For | |
646 | most applications, the zlib format should be used as is. Note that comments | |
647 | above on the use in deflateInit2() applies to the magnitude of windowBits. | |
648 | ||
649 | windowBits can also be greater than 15 for optional gzip decoding. Add | |
650 | 32 to windowBits to enable zlib and gzip decoding with automatic header | |
651 | detection, or add 16 to decode only the gzip format (the zlib format will | |
652 | return a Z_DATA_ERROR). | |
653 | ||
654 | inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough | |
655 | memory, Z_STREAM_ERROR if a parameter is invalid (such as a negative | |
656 | memLevel). msg is set to null if there is no error message. inflateInit2 | |
657 | does not perform any decompression apart from reading the zlib header if | |
658 | present: this will be done by inflate(). (So next_in and avail_in may be | |
659 | modified, but next_out and avail_out are unchanged.) | |
660 | */ | |
661 | ||
662 | ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm, | |
663 | const Bytef *dictionary, | |
664 | uInt dictLength)); | |
665 | /* | |
666 | Initializes the decompression dictionary from the given uncompressed byte | |
667 | sequence. This function must be called immediately after a call of inflate | |
668 | if this call returned Z_NEED_DICT. The dictionary chosen by the compressor | |
669 | can be determined from the adler32 value returned by this call of | |
670 | inflate. The compressor and decompressor must use exactly the same | |
671 | dictionary (see deflateSetDictionary). | |
672 | ||
673 | inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a | |
674 | parameter is invalid (such as NULL dictionary) or the stream state is | |
675 | inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the | |
676 | expected one (incorrect adler32 value). inflateSetDictionary does not | |
677 | perform any decompression: this will be done by subsequent calls of | |
678 | inflate(). | |
679 | */ | |
680 | ||
681 | ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm)); | |
682 | /* | |
683 | Skips invalid compressed data until a full flush point (see above the | |
684 | description of deflate with Z_FULL_FLUSH) can be found, or until all | |
685 | available input is skipped. No output is provided. | |
686 | ||
687 | inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR | |
688 | if no more input was provided, Z_DATA_ERROR if no flush point has been found, | |
689 | or Z_STREAM_ERROR if the stream structure was inconsistent. In the success | |
690 | case, the application may save the current current value of total_in which | |
691 | indicates where valid compressed data was found. In the error case, the | |
692 | application may repeatedly call inflateSync, providing more input each time, | |
693 | until success or end of the input data. | |
694 | */ | |
695 | ||
696 | ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest, | |
697 | z_streamp source)); | |
698 | /* | |
699 | Sets the destination stream as a complete copy of the source stream. | |
700 | ||
701 | This function can be useful when randomly accessing a large stream. The | |
702 | first pass through the stream can periodically record the inflate state, | |
703 | allowing restarting inflate at those points when randomly accessing the | |
704 | stream. | |
705 | ||
706 | inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not | |
707 | enough memory, Z_STREAM_ERROR if the source stream state was inconsistent | |
708 | (such as zalloc being NULL). msg is left unchanged in both source and | |
709 | destination. | |
710 | */ | |
711 | ||
712 | ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm)); | |
713 | /* | |
714 | This function is equivalent to inflateEnd followed by inflateInit, | |
715 | but does not free and reallocate all the internal decompression state. | |
716 | The stream will keep attributes that may have been set by inflateInit2. | |
717 | ||
718 | inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source | |
719 | stream state was inconsistent (such as zalloc or state being NULL). | |
720 | */ | |
721 | ||
722 | /* | |
723 | ZEXTERN int ZEXPORT inflateBackInit OF((z_stream FAR *strm, int windowBits, | |
724 | unsigned char FAR *window)); | |
725 | ||
726 | Initialize the internal stream state for decompression using inflateBack() | |
727 | calls. The fields zalloc, zfree and opaque in strm must be initialized | |
728 | before the call. If zalloc and zfree are Z_NULL, then the default library- | |
729 | derived memory allocation routines are used. windowBits is the base two | |
730 | logarithm of the window size, in the range 8..15. window is a caller | |
731 | supplied buffer of that size. Except for special applications where it is | |
732 | assured that deflate was used with small window sizes, windowBits must be 15 | |
733 | and a 32K byte window must be supplied to be able to decompress general | |
734 | deflate streams. | |
735 | ||
736 | See inflateBack() for the usage of these routines. | |
737 | ||
738 | inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of | |
739 | the paramaters are invalid, Z_MEM_ERROR if the internal state could not | |
740 | be allocated, or Z_VERSION_ERROR if the version of the library does not | |
741 | match the version of the header file. | |
742 | */ | |
743 | ||
744 | typedef unsigned (*in_func) OF((void FAR *, unsigned char FAR * FAR *)); | |
745 | typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned)); | |
746 | ||
747 | ZEXTERN int ZEXPORT inflateBack OF((z_stream FAR *strm, | |
748 | in_func in, void FAR *in_desc, | |
749 | out_func out, void FAR *out_desc)); | |
750 | /* | |
751 | inflateBack() does a raw inflate with a single call using a call-back | |
752 | interface for input and output. This is more efficient than inflate() for | |
753 | file i/o applications in that it avoids copying between the output and the | |
754 | sliding window by simply making the window itself the output buffer. This | |
755 | function trusts the application to not change the output buffer passed by | |
756 | the output function, at least until inflateBack() returns. | |
757 | ||
758 | inflateBackInit() must be called first to allocate the internal state | |
759 | and to initialize the state with the user-provided window buffer. | |
760 | inflateBack() may then be used multiple times to inflate a complete, raw | |
761 | deflate stream with each call. inflateBackEnd() is then called to free | |
762 | the allocated state. | |
763 | ||
764 | A raw deflate stream is one with no zlib or gzip header or trailer. | |
765 | This routine would normally be used in a utility that reads zip or gzip | |
766 | files and writes out uncompressed files. The utility would decode the | |
767 | header and process the trailer on its own, hence this routine expects | |
768 | only the raw deflate stream to decompress. This is different from the | |
769 | normal behavior of inflate(), which expects either a zlib or gzip header and | |
770 | trailer around the deflate stream. | |
771 | ||
772 | inflateBack() uses two subroutines supplied by the caller that are then | |
773 | called by inflateBack() for input and output. inflateBack() calls those | |
774 | routines until it reads a complete deflate stream and writes out all of the | |
775 | uncompressed data, or until it encounters an error. The function's | |
776 | parameters and return types are defined above in the in_func and out_func | |
777 | typedefs. inflateBack() will call in(in_desc, &buf) which should return the | |
778 | number of bytes of provided input, and a pointer to that input in buf. If | |
779 | there is no input available, in() must return zero--buf is ignored in that | |
780 | case--and inflateBack() will return a buffer error. inflateBack() will call | |
781 | out(out_desc, buf, len) to write the uncompressed data buf[0..len-1]. out() | |
782 | should return zero on success, or non-zero on failure. If out() returns | |
783 | non-zero, inflateBack() will return with an error. Neither in() nor out() | |
784 | are permitted to change the contents of the window provided to | |
785 | inflateBackInit(), which is also the buffer that out() uses to write from. | |
786 | The length written by out() will be at most the window size. Any non-zero | |
787 | amount of input may be provided by in(). | |
788 | ||
789 | For convenience, inflateBack() can be provided input on the first call by | |
790 | setting strm->next_in and strm->avail_in. If that input is exhausted, then | |
791 | in() will be called. Therefore strm->next_in must be initialized before | |
792 | calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called | |
793 | immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in | |
794 | must also be initialized, and then if strm->avail_in is not zero, input will | |
795 | initially be taken from strm->next_in[0 .. strm->avail_in - 1]. | |
796 | ||
797 | The in_desc and out_desc parameters of inflateBack() is passed as the | |
798 | first parameter of in() and out() respectively when they are called. These | |
799 | descriptors can be optionally used to pass any information that the caller- | |
800 | supplied in() and out() functions need to do their job. | |
801 | ||
802 | On return, inflateBack() will set strm->next_in and strm->avail_in to | |
803 | pass back any unused input that was provided by the last in() call. The | |
804 | return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR | |
805 | if in() or out() returned an error, Z_DATA_ERROR if there was a format | |
806 | error in the deflate stream (in which case strm->msg is set to indicate the | |
807 | nature of the error), or Z_STREAM_ERROR if the stream was not properly | |
808 | initialized. In the case of Z_BUF_ERROR, an input or output error can be | |
809 | distinguished using strm->next_in which will be Z_NULL only if in() returned | |
810 | an error. If strm->next is not Z_NULL, then the Z_BUF_ERROR was due to | |
811 | out() returning non-zero. (in() will always be called before out(), so | |
812 | strm->next_in is assured to be defined if out() returns non-zero.) Note | |
813 | that inflateBack() cannot return Z_OK. | |
814 | */ | |
815 | ||
816 | ZEXTERN int ZEXPORT inflateBackEnd OF((z_stream FAR *strm)); | |
817 | /* | |
818 | All memory allocated by inflateBackInit() is freed. | |
819 | ||
820 | inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream | |
821 | state was inconsistent. | |
822 | */ | |
823 | ||
824 | ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void)); | |
825 | /* Return flags indicating compile-time options. | |
826 | ||
827 | Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other: | |
828 | 1.0: size of uInt | |
829 | 3.2: size of uLong | |
830 | 5.4: size of voidpf (pointer) | |
831 | 7.6: size of z_off_t | |
832 | ||
833 | Compiler, assembler, and debug options: | |
834 | 8: DEBUG | |
835 | 9: ASMV or ASMINF -- use ASM code | |
836 | 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention | |
837 | 11: 0 (reserved) | |
838 | ||
839 | One-time table building (smaller code, but not thread-safe if true): | |
840 | 12: BUILDFIXED -- build static block decoding tables when needed | |
841 | 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed | |
842 | 14,15: 0 (reserved) | |
843 | ||
844 | Library content (indicates missing functionality): | |
845 | 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking | |
846 | deflate code when not needed) | |
847 | 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect | |
848 | and decode gzip streams (to avoid linking crc code) | |
849 | 18-19: 0 (reserved) | |
850 | ||
851 | Operation variations (changes in library functionality): | |
852 | 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate | |
853 | 21: FASTEST -- deflate algorithm with only one, lowest compression level | |
854 | 22,23: 0 (reserved) | |
855 | ||
856 | The sprintf variant used by gzprintf (zero is best): | |
857 | 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format | |
858 | 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure! | |
859 | 26: 0 = returns value, 1 = void -- 1 means inferred string length returned | |
860 | ||
861 | Remainder: | |
862 | 27-31: 0 (reserved) | |
863 | */ | |
864 | ||
865 | ||
866 | /* utility functions */ | |
867 | ||
868 | /* | |
869 | The following utility functions are implemented on top of the | |
870 | basic stream-oriented functions. To simplify the interface, some | |
871 | default options are assumed (compression level and memory usage, | |
872 | standard memory allocation functions). The source code of these | |
873 | utility functions can easily be modified if you need special options. | |
874 | */ | |
875 | ||
876 | ZEXTERN int ZEXPORT compress OF((Bytef *dest, uLongf *destLen, | |
877 | const Bytef *source, uLong sourceLen)); | |
878 | /* | |
879 | Compresses the source buffer into the destination buffer. sourceLen is | |
880 | the byte length of the source buffer. Upon entry, destLen is the total | |
881 | size of the destination buffer, which must be at least the value returned | |
882 | by compressBound(sourceLen). Upon exit, destLen is the actual size of the | |
883 | compressed buffer. | |
884 | This function can be used to compress a whole file at once if the | |
885 | input file is mmap'ed. | |
886 | compress returns Z_OK if success, Z_MEM_ERROR if there was not | |
887 | enough memory, Z_BUF_ERROR if there was not enough room in the output | |
888 | buffer. | |
889 | */ | |
890 | ||
891 | ZEXTERN int ZEXPORT compress2 OF((Bytef *dest, uLongf *destLen, | |
892 | const Bytef *source, uLong sourceLen, | |
893 | int level)); | |
894 | /* | |
895 | Compresses the source buffer into the destination buffer. The level | |
896 | parameter has the same meaning as in deflateInit. sourceLen is the byte | |
897 | length of the source buffer. Upon entry, destLen is the total size of the | |
898 | destination buffer, which must be at least the value returned by | |
899 | compressBound(sourceLen). Upon exit, destLen is the actual size of the | |
900 | compressed buffer. | |
901 | ||
902 | compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough | |
903 | memory, Z_BUF_ERROR if there was not enough room in the output buffer, | |
904 | Z_STREAM_ERROR if the level parameter is invalid. | |
905 | */ | |
906 | ||
907 | ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen)); | |
908 | /* | |
909 | compressBound() returns an upper bound on the compressed size after | |
910 | compress() or compress2() on sourceLen bytes. It would be used before | |
911 | a compress() or compress2() call to allocate the destination buffer. | |
912 | */ | |
913 | ||
914 | ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen, | |
915 | const Bytef *source, uLong sourceLen)); | |
916 | /* | |
917 | Decompresses the source buffer into the destination buffer. sourceLen is | |
918 | the byte length of the source buffer. Upon entry, destLen is the total | |
919 | size of the destination buffer, which must be large enough to hold the | |
920 | entire uncompressed data. (The size of the uncompressed data must have | |
921 | been saved previously by the compressor and transmitted to the decompressor | |
922 | by some mechanism outside the scope of this compression library.) | |
923 | Upon exit, destLen is the actual size of the compressed buffer. | |
924 | This function can be used to decompress a whole file at once if the | |
925 | input file is mmap'ed. | |
926 | ||
927 | uncompress returns Z_OK if success, Z_MEM_ERROR if there was not | |
928 | enough memory, Z_BUF_ERROR if there was not enough room in the output | |
929 | buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete. | |
930 | */ | |
931 | ||
932 | ||
933 | typedef voidp gzFile; | |
934 | ||
935 | ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode)); | |
936 | /* | |
937 | Opens a gzip (.gz) file for reading or writing. The mode parameter | |
938 | is as in fopen ("rb" or "wb") but can also include a compression level | |
939 | ("wb9") or a strategy: 'f' for filtered data as in "wb6f", 'h' for | |
940 | Huffman only compression as in "wb1h", or 'R' for run-length encoding | |
941 | as in "wb1R". (See the description of deflateInit2 for more information | |
942 | about the strategy parameter.) | |
943 | ||
944 | gzopen can be used to read a file which is not in gzip format; in this | |
945 | case gzread will directly read from the file without decompression. | |
946 | ||
947 | gzopen returns NULL if the file could not be opened or if there was | |
948 | insufficient memory to allocate the (de)compression state; errno | |
949 | can be checked to distinguish the two cases (if errno is zero, the | |
950 | zlib error is Z_MEM_ERROR). */ | |
951 | ||
952 | ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode)); | |
953 | /* | |
954 | gzdopen() associates a gzFile with the file descriptor fd. File | |
955 | descriptors are obtained from calls like open, dup, creat, pipe or | |
956 | fileno (in the file has been previously opened with fopen). | |
957 | The mode parameter is as in gzopen. | |
958 | The next call of gzclose on the returned gzFile will also close the | |
959 | file descriptor fd, just like fclose(fdopen(fd), mode) closes the file | |
960 | descriptor fd. If you want to keep fd open, use gzdopen(dup(fd), mode). | |
961 | gzdopen returns NULL if there was insufficient memory to allocate | |
962 | the (de)compression state. | |
963 | */ | |
964 | ||
965 | ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy)); | |
966 | /* | |
967 | Dynamically update the compression level or strategy. See the description | |
968 | of deflateInit2 for the meaning of these parameters. | |
969 | gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not | |
970 | opened for writing. | |
971 | */ | |
972 | ||
973 | ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len)); | |
974 | /* | |
975 | Reads the given number of uncompressed bytes from the compressed file. | |
976 | If the input file was not in gzip format, gzread copies the given number | |
977 | of bytes into the buffer. | |
978 | gzread returns the number of uncompressed bytes actually read (0 for | |
979 | end of file, -1 for error). */ | |
980 | ||
981 | ZEXTERN int ZEXPORT gzwrite OF((gzFile file, | |
982 | voidpc buf, unsigned len)); | |
983 | /* | |
984 | Writes the given number of uncompressed bytes into the compressed file. | |
985 | gzwrite returns the number of uncompressed bytes actually written | |
986 | (0 in case of error). | |
987 | */ | |
988 | ||
989 | ZEXTERN int ZEXPORTVA gzprintf OF((gzFile file, const char *format, ...)); | |
990 | /* | |
991 | Converts, formats, and writes the args to the compressed file under | |
992 | control of the format string, as in fprintf. gzprintf returns the number of | |
993 | uncompressed bytes actually written (0 in case of error). The number of | |
994 | uncompressed bytes written is limited to 4095. The caller should assure that | |
995 | this limit is not exceeded. If it is exceeded, then gzprintf() will return | |
996 | return an error (0) with nothing written. In this case, there may also be a | |
997 | buffer overflow with unpredictable consequences, which is possible only if | |
998 | zlib was compiled with the insecure functions sprintf() or vsprintf() | |
999 | because the secure snprintf() or vsnprintf() functions were not available. | |
1000 | */ | |
1001 | ||
1002 | ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s)); | |
1003 | /* | |
1004 | Writes the given null-terminated string to the compressed file, excluding | |
1005 | the terminating null character. | |
1006 | gzputs returns the number of characters written, or -1 in case of error. | |
1007 | */ | |
1008 | ||
1009 | ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len)); | |
1010 | /* | |
1011 | Reads bytes from the compressed file until len-1 characters are read, or | |
1012 | a newline character is read and transferred to buf, or an end-of-file | |
1013 | condition is encountered. The string is then terminated with a null | |
1014 | character. | |
1015 | gzgets returns buf, or Z_NULL in case of error. | |
1016 | */ | |
1017 | ||
1018 | ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c)); | |
1019 | /* | |
1020 | Writes c, converted to an unsigned char, into the compressed file. | |
1021 | gzputc returns the value that was written, or -1 in case of error. | |
1022 | */ | |
1023 | ||
1024 | ZEXTERN int ZEXPORT gzgetc OF((gzFile file)); | |
1025 | /* | |
1026 | Reads one byte from the compressed file. gzgetc returns this byte | |
1027 | or -1 in case of end of file or error. | |
1028 | */ | |
1029 | ||
1030 | ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file)); | |
1031 | /* | |
1032 | Push one character back onto the stream to be read again later. | |
1033 | Only one character of push-back is allowed. gzungetc() returns the | |
1034 | character pushed, or -1 on failure. gzungetc() will fail if a | |
1035 | character has been pushed but not read yet, or if c is -1. The pushed | |
1036 | character will be discarded if the stream is repositioned with gzseek() | |
1037 | or gzrewind(). | |
1038 | */ | |
1039 | ||
1040 | ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush)); | |
1041 | /* | |
1042 | Flushes all pending output into the compressed file. The parameter | |
1043 | flush is as in the deflate() function. The return value is the zlib | |
1044 | error number (see function gzerror below). gzflush returns Z_OK if | |
1045 | the flush parameter is Z_FINISH and all output could be flushed. | |
1046 | gzflush should be called only when strictly necessary because it can | |
1047 | degrade compression. | |
1048 | */ | |
1049 | ||
1050 | ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file, | |
1051 | z_off_t offset, int whence)); | |
1052 | /* | |
1053 | Sets the starting position for the next gzread or gzwrite on the | |
1054 | given compressed file. The offset represents a number of bytes in the | |
1055 | uncompressed data stream. The whence parameter is defined as in lseek(2); | |
1056 | the value SEEK_END is not supported. | |
1057 | If the file is opened for reading, this function is emulated but can be | |
1058 | extremely slow. If the file is opened for writing, only forward seeks are | |
1059 | supported; gzseek then compresses a sequence of zeroes up to the new | |
1060 | starting position. | |
1061 | ||
1062 | gzseek returns the resulting offset location as measured in bytes from | |
1063 | the beginning of the uncompressed stream, or -1 in case of error, in | |
1064 | particular if the file is opened for writing and the new starting position | |
1065 | would be before the current position. | |
1066 | */ | |
1067 | ||
1068 | ZEXTERN int ZEXPORT gzrewind OF((gzFile file)); | |
1069 | /* | |
1070 | Rewinds the given file. This function is supported only for reading. | |
1071 | ||
1072 | gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET) | |
1073 | */ | |
1074 | ||
1075 | ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file)); | |
1076 | /* | |
1077 | Returns the starting position for the next gzread or gzwrite on the | |
1078 | given compressed file. This position represents a number of bytes in the | |
1079 | uncompressed data stream. | |
1080 | ||
1081 | gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR) | |
1082 | */ | |
1083 | ||
1084 | ZEXTERN int ZEXPORT gzeof OF((gzFile file)); | |
1085 | /* | |
1086 | Returns 1 when EOF has previously been detected reading the given | |
1087 | input stream, otherwise zero. | |
1088 | */ | |
1089 | ||
1090 | ZEXTERN int ZEXPORT gzclose OF((gzFile file)); | |
1091 | /* | |
1092 | Flushes all pending output if necessary, closes the compressed file | |
1093 | and deallocates all the (de)compression state. The return value is the zlib | |
1094 | error number (see function gzerror below). | |
1095 | */ | |
1096 | ||
1097 | ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum)); | |
1098 | /* | |
1099 | Returns the error message for the last error which occurred on the | |
1100 | given compressed file. errnum is set to zlib error number. If an | |
1101 | error occurred in the file system and not in the compression library, | |
1102 | errnum is set to Z_ERRNO and the application may consult errno | |
1103 | to get the exact error code. | |
1104 | */ | |
1105 | ||
1106 | ZEXTERN void ZEXPORT gzclearerr OF((gzFile file)); | |
1107 | /* | |
1108 | Clears the error and end-of-file flags for file. This is analogous to the | |
1109 | clearerr() function in stdio. This is useful for continuing to read a gzip | |
1110 | file that is being written concurrently. | |
1111 | */ | |
1112 | ||
1113 | /* checksum functions */ | |
1114 | ||
1115 | /* | |
1116 | These functions are not related to compression but are exported | |
1117 | anyway because they might be useful in applications using the | |
1118 | compression library. | |
1119 | */ | |
1120 | ||
1121 | ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len)); | |
1122 | ||
1123 | /* | |
1124 | Update a running Adler-32 checksum with the bytes buf[0..len-1] and | |
1125 | return the updated checksum. If buf is NULL, this function returns | |
1126 | the required initial value for the checksum. | |
1127 | An Adler-32 checksum is almost as reliable as a CRC32 but can be computed | |
1128 | much faster. Usage example: | |
1129 | ||
1130 | uLong adler = adler32(0L, Z_NULL, 0); | |
1131 | ||
1132 | while (read_buffer(buffer, length) != EOF) { | |
1133 | adler = adler32(adler, buffer, length); | |
1134 | } | |
1135 | if (adler != original_adler) error(); | |
1136 | */ | |
1137 | ||
1138 | ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len)); | |
1139 | /* | |
1140 | Update a running crc with the bytes buf[0..len-1] and return the updated | |
1141 | crc. If buf is NULL, this function returns the required initial value | |
1142 | for the crc. Pre- and post-conditioning (one's complement) is performed | |
1143 | within this function so it shouldn't be done by the application. | |
1144 | Usage example: | |
1145 | ||
1146 | uLong crc = crc32(0L, Z_NULL, 0); | |
1147 | ||
1148 | while (read_buffer(buffer, length) != EOF) { | |
1149 | crc = crc32(crc, buffer, length); | |
1150 | } | |
1151 | if (crc != original_crc) error(); | |
1152 | */ | |
1153 | ||
1154 | ||
1155 | /* various hacks, don't look :) */ | |
1156 | ||
1157 | /* deflateInit and inflateInit are macros to allow checking the zlib version | |
1158 | * and the compiler's view of z_stream: | |
1159 | */ | |
1160 | ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level, | |
1161 | const char *version, int stream_size)); | |
1162 | ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm, | |
1163 | const char *version, int stream_size)); | |
1164 | ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method, | |
1165 | int windowBits, int memLevel, | |
1166 | int strategy, const char *version, | |
1167 | int stream_size)); | |
1168 | ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits, | |
1169 | const char *version, int stream_size)); | |
1170 | ZEXTERN int ZEXPORT inflateBackInit_ OF((z_stream FAR *strm, int windowBits, | |
1171 | unsigned char FAR *window, | |
1172 | const char *version, | |
1173 | int stream_size)); | |
1174 | #define deflateInit(strm, level) \ | |
1175 | deflateInit_((strm), (level), ZLIB_VERSION, sizeof(z_stream)) | |
1176 | #define inflateInit(strm) \ | |
1177 | inflateInit_((strm), ZLIB_VERSION, sizeof(z_stream)) | |
1178 | #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \ | |
1179 | deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\ | |
1180 | (strategy), ZLIB_VERSION, sizeof(z_stream)) | |
1181 | #define inflateInit2(strm, windowBits) \ | |
1182 | inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream)) | |
1183 | #define inflateBackInit(strm, windowBits, window) \ | |
1184 | inflateBackInit_((strm), (windowBits), (window), \ | |
1185 | ZLIB_VERSION, sizeof(z_stream)) | |
1186 | ||
1187 | ||
1188 | #if !defined(ZUTIL_H) && !defined(NO_DUMMY_DECL) | |
1189 | struct internal_state {int dummy;}; /* hack for buggy compilers */ | |
1190 | #endif | |
1191 | ||
1192 | ZEXTERN const char * ZEXPORT zError OF((int err)); | |
1193 | ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp z)); | |
1194 | ZEXTERN const uLongf * ZEXPORT get_crc_table OF((void)); | |
1195 | ||
1196 | #ifdef __cplusplus | |
1197 | } | |
1198 | #endif | |
1199 | ||
1200 | #endif /* ZLIB_H */ |