]>
Commit | Line | Data |
---|---|---|
c801d85f | 1 | /* zlib.h -- interface of the 'zlib' general purpose compression library |
ba0052f3 | 2 | version 1.2.2, October 3rd, 2004 |
c801d85f | 3 | |
ba0052f3 | 4 | Copyright (C) 1995-2004 Jean-loup Gailly and Mark Adler |
c801d85f KB |
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 | |
51dbdf87 | 27 | Comments) 1950 to 1952 in the files http://www.ietf.org/rfc/rfc1950.txt |
c801d85f KB |
28 | (zlib format), rfc1951.txt (deflate format) and rfc1952.txt (gzip format). |
29 | */ | |
30 | ||
51dbdf87 VS |
31 | #ifndef ZLIB_H |
32 | #define ZLIB_H | |
c801d85f | 33 | |
a4019ec2 | 34 | #include "zconf.h" |
c801d85f KB |
35 | |
36 | #ifdef __cplusplus | |
37 | extern "C" { | |
38 | #endif | |
39 | ||
ba0052f3 VS |
40 | #define ZLIB_VERSION "1.2.2" |
41 | #define ZLIB_VERNUM 0x1220 | |
c801d85f | 42 | |
51dbdf87 | 43 | /* |
c801d85f KB |
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 | ||
ba0052f3 VS |
56 | The compressed data format used by default by the in-memory functions is |
57 | the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped | |
58 | around a deflate stream, which is itself documented in RFC 1951. | |
51dbdf87 | 59 | |
c801d85f | 60 | The library also supports reading and writing files in gzip (.gz) format |
51dbdf87 VS |
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 | ||
ba0052f3 VS |
65 | This library can optionally read and write gzip streams in memory as well. |
66 | ||
51dbdf87 VS |
67 | The zlib format was designed to be compact and fast for use in memory |
68 | and on communications channels. The gzip format was designed for single- | |
69 | file compression on file systems, has a larger header than zlib to maintain | |
70 | directory information, and uses a different, slower check method than zlib. | |
71 | ||
c801d85f KB |
72 | The library does not install any signal handler. The decoder checks |
73 | the consistency of the compressed data, so the library should never | |
74 | crash even in case of corrupted input. | |
75 | */ | |
76 | ||
77 | typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size)); | |
78 | typedef void (*free_func) OF((voidpf opaque, voidpf address)); | |
79 | ||
80 | struct internal_state; | |
81 | ||
82 | typedef struct z_stream_s { | |
83 | Bytef *next_in; /* next input byte */ | |
84 | uInt avail_in; /* number of bytes available at next_in */ | |
85 | uLong total_in; /* total nb of input bytes read so far */ | |
86 | ||
87 | Bytef *next_out; /* next output byte should be put there */ | |
88 | uInt avail_out; /* remaining free space at next_out */ | |
89 | uLong total_out; /* total nb of bytes output so far */ | |
90 | ||
91 | char *msg; /* last error message, NULL if no error */ | |
92 | struct internal_state FAR *state; /* not visible by applications */ | |
93 | ||
94 | alloc_func zalloc; /* used to allocate the internal state */ | |
95 | free_func zfree; /* used to free the internal state */ | |
96 | voidpf opaque; /* private data object passed to zalloc and zfree */ | |
97 | ||
98 | int data_type; /* best guess about the data type: ascii or binary */ | |
99 | uLong adler; /* adler32 value of the uncompressed data */ | |
100 | uLong reserved; /* reserved for future use */ | |
101 | } z_stream; | |
102 | ||
103 | typedef z_stream FAR *z_streamp; | |
104 | ||
105 | /* | |
106 | The application must update next_in and avail_in when avail_in has | |
107 | dropped to zero. It must update next_out and avail_out when avail_out | |
108 | has dropped to zero. The application must initialize zalloc, zfree and | |
109 | opaque before calling the init function. All other fields are set by the | |
110 | compression library and must not be updated by the application. | |
111 | ||
112 | The opaque value provided by the application will be passed as the first | |
113 | parameter for calls of zalloc and zfree. This can be useful for custom | |
114 | memory management. The compression library attaches no meaning to the | |
115 | opaque value. | |
116 | ||
117 | zalloc must return Z_NULL if there is not enough memory for the object. | |
118 | If zlib is used in a multi-threaded application, zalloc and zfree must be | |
119 | thread safe. | |
120 | ||
121 | On 16-bit systems, the functions zalloc and zfree must be able to allocate | |
122 | exactly 65536 bytes, but will not be required to allocate more than this | |
123 | if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, | |
124 | pointers returned by zalloc for objects of exactly 65536 bytes *must* | |
125 | have their offset normalized to zero. The default allocation function | |
126 | provided by this library ensures this (see zutil.c). To reduce memory | |
127 | requirements and avoid any allocation of 64K objects, at the expense of | |
128 | compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h). | |
129 | ||
130 | The fields total_in and total_out can be used for statistics or | |
131 | progress reports. After compression, total_in holds the total size of | |
132 | the uncompressed data and may be saved for use in the decompressor | |
133 | (particularly if the decompressor wants to decompress everything in | |
134 | a single step). | |
135 | */ | |
136 | ||
137 | /* constants */ | |
138 | ||
139 | #define Z_NO_FLUSH 0 | |
140 | #define Z_PARTIAL_FLUSH 1 /* will be removed, use Z_SYNC_FLUSH instead */ | |
141 | #define Z_SYNC_FLUSH 2 | |
142 | #define Z_FULL_FLUSH 3 | |
143 | #define Z_FINISH 4 | |
51dbdf87 VS |
144 | #define Z_BLOCK 5 |
145 | /* Allowed flush values; see deflate() and inflate() below for details */ | |
c801d85f KB |
146 | |
147 | #define Z_OK 0 | |
148 | #define Z_STREAM_END 1 | |
149 | #define Z_NEED_DICT 2 | |
150 | #define Z_ERRNO (-1) | |
151 | #define Z_STREAM_ERROR (-2) | |
152 | #define Z_DATA_ERROR (-3) | |
153 | #define Z_MEM_ERROR (-4) | |
154 | #define Z_BUF_ERROR (-5) | |
155 | #define Z_VERSION_ERROR (-6) | |
156 | /* Return codes for the compression/decompression functions. Negative | |
157 | * values are errors, positive values are used for special but normal events. | |
158 | */ | |
159 | ||
160 | #define Z_NO_COMPRESSION 0 | |
161 | #define Z_BEST_SPEED 1 | |
162 | #define Z_BEST_COMPRESSION 9 | |
163 | #define Z_DEFAULT_COMPRESSION (-1) | |
164 | /* compression levels */ | |
165 | ||
166 | #define Z_FILTERED 1 | |
167 | #define Z_HUFFMAN_ONLY 2 | |
51dbdf87 | 168 | #define Z_RLE 3 |
c801d85f KB |
169 | #define Z_DEFAULT_STRATEGY 0 |
170 | /* compression strategy; see deflateInit2() below for details */ | |
171 | ||
172 | #define Z_BINARY 0 | |
173 | #define Z_ASCII 1 | |
174 | #define Z_UNKNOWN 2 | |
51dbdf87 | 175 | /* Possible values of the data_type field (though see inflate()) */ |
c801d85f KB |
176 | |
177 | #define Z_DEFLATED 8 | |
178 | /* The deflate compression method (the only one supported in this version) */ | |
179 | ||
180 | #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */ | |
181 | ||
182 | #define zlib_version zlibVersion() | |
183 | /* for compatibility with versions < 1.0.2 */ | |
184 | ||
185 | /* basic functions */ | |
186 | ||
a4019ec2 | 187 | ZEXTERN const char * ZEXPORT zlibVersion OF((void)); |
c801d85f KB |
188 | /* The application can compare zlibVersion and ZLIB_VERSION for consistency. |
189 | If the first character differs, the library code actually used is | |
190 | not compatible with the zlib.h header file used by the application. | |
191 | This check is automatically made by deflateInit and inflateInit. | |
192 | */ | |
193 | ||
51dbdf87 | 194 | /* |
a4019ec2 | 195 | ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level)); |
c801d85f KB |
196 | |
197 | Initializes the internal stream state for compression. The fields | |
198 | zalloc, zfree and opaque must be initialized before by the caller. | |
199 | If zalloc and zfree are set to Z_NULL, deflateInit updates them to | |
200 | use default allocation functions. | |
201 | ||
202 | The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9: | |
203 | 1 gives best speed, 9 gives best compression, 0 gives no compression at | |
204 | all (the input data is simply copied a block at a time). | |
205 | Z_DEFAULT_COMPRESSION requests a default compromise between speed and | |
206 | compression (currently equivalent to level 6). | |
207 | ||
208 | deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not | |
209 | enough memory, Z_STREAM_ERROR if level is not a valid compression level, | |
210 | Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible | |
211 | with the version assumed by the caller (ZLIB_VERSION). | |
212 | msg is set to null if there is no error message. deflateInit does not | |
213 | perform any compression: this will be done by deflate(). | |
214 | */ | |
215 | ||
216 | ||
a4019ec2 | 217 | ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush)); |
c801d85f KB |
218 | /* |
219 | deflate compresses as much data as possible, and stops when the input | |
220 | buffer becomes empty or the output buffer becomes full. It may introduce some | |
221 | output latency (reading input without producing any output) except when | |
222 | forced to flush. | |
223 | ||
224 | The detailed semantics are as follows. deflate performs one or both of the | |
225 | following actions: | |
226 | ||
227 | - Compress more input starting at next_in and update next_in and avail_in | |
228 | accordingly. If not all input can be processed (because there is not | |
229 | enough room in the output buffer), next_in and avail_in are updated and | |
230 | processing will resume at this point for the next call of deflate(). | |
231 | ||
232 | - Provide more output starting at next_out and update next_out and avail_out | |
233 | accordingly. This action is forced if the parameter flush is non zero. | |
234 | Forcing flush frequently degrades the compression ratio, so this parameter | |
235 | should be set only when necessary (in interactive applications). | |
236 | Some output may be provided even if flush is not set. | |
237 | ||
238 | Before the call of deflate(), the application should ensure that at least | |
239 | one of the actions is possible, by providing more input and/or consuming | |
240 | more output, and updating avail_in or avail_out accordingly; avail_out | |
241 | should never be zero before the call. The application can consume the | |
242 | compressed output when it wants, for example when the output buffer is full | |
243 | (avail_out == 0), or after each call of deflate(). If deflate returns Z_OK | |
244 | and with zero avail_out, it must be called again after making room in the | |
245 | output buffer because there might be more output pending. | |
246 | ||
247 | If the parameter flush is set to Z_SYNC_FLUSH, all pending output is | |
248 | flushed to the output buffer and the output is aligned on a byte boundary, so | |
249 | that the decompressor can get all input data available so far. (In particular | |
250 | avail_in is zero after the call if enough output space has been provided | |
251 | before the call.) Flushing may degrade compression for some compression | |
252 | algorithms and so it should be used only when necessary. | |
253 | ||
254 | If flush is set to Z_FULL_FLUSH, all output is flushed as with | |
255 | Z_SYNC_FLUSH, and the compression state is reset so that decompression can | |
256 | restart from this point if previous compressed data has been damaged or if | |
257 | random access is desired. Using Z_FULL_FLUSH too often can seriously degrade | |
258 | the compression. | |
259 | ||
260 | If deflate returns with avail_out == 0, this function must be called again | |
261 | with the same value of the flush parameter and more output space (updated | |
262 | avail_out), until the flush is complete (deflate returns with non-zero | |
51dbdf87 VS |
263 | avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that |
264 | avail_out is greater than six to avoid repeated flush markers due to | |
265 | avail_out == 0 on return. | |
c801d85f KB |
266 | |
267 | If the parameter flush is set to Z_FINISH, pending input is processed, | |
268 | pending output is flushed and deflate returns with Z_STREAM_END if there | |
269 | was enough output space; if deflate returns with Z_OK, this function must be | |
270 | called again with Z_FINISH and more output space (updated avail_out) but no | |
271 | more input data, until it returns with Z_STREAM_END or an error. After | |
272 | deflate has returned Z_STREAM_END, the only possible operations on the | |
273 | stream are deflateReset or deflateEnd. | |
51dbdf87 | 274 | |
c801d85f KB |
275 | Z_FINISH can be used immediately after deflateInit if all the compression |
276 | is to be done in a single step. In this case, avail_out must be at least | |
51dbdf87 | 277 | the value returned by deflateBound (see below). If deflate does not return |
c801d85f KB |
278 | Z_STREAM_END, then it must be called again as described above. |
279 | ||
280 | deflate() sets strm->adler to the adler32 checksum of all input read | |
281 | so far (that is, total_in bytes). | |
282 | ||
283 | deflate() may update data_type if it can make a good guess about | |
284 | the input data type (Z_ASCII or Z_BINARY). In doubt, the data is considered | |
285 | binary. This field is only for information purposes and does not affect | |
286 | the compression algorithm in any manner. | |
287 | ||
288 | deflate() returns Z_OK if some progress has been made (more input | |
289 | processed or more output produced), Z_STREAM_END if all input has been | |
290 | consumed and all output has been produced (only when flush is set to | |
291 | Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example | |
a4019ec2 | 292 | if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible |
51dbdf87 VS |
293 | (for example avail_in or avail_out was zero). Note that Z_BUF_ERROR is not |
294 | fatal, and deflate() can be called again with more input and more output | |
295 | space to continue compressing. | |
c801d85f KB |
296 | */ |
297 | ||
298 | ||
a4019ec2 | 299 | ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm)); |
c801d85f KB |
300 | /* |
301 | All dynamically allocated data structures for this stream are freed. | |
302 | This function discards any unprocessed input and does not flush any | |
303 | pending output. | |
304 | ||
305 | deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the | |
306 | stream state was inconsistent, Z_DATA_ERROR if the stream was freed | |
307 | prematurely (some input or output was discarded). In the error case, | |
308 | msg may be set but then points to a static string (which must not be | |
309 | deallocated). | |
310 | */ | |
311 | ||
312 | ||
51dbdf87 | 313 | /* |
a4019ec2 | 314 | ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm)); |
c801d85f KB |
315 | |
316 | Initializes the internal stream state for decompression. The fields | |
317 | next_in, avail_in, zalloc, zfree and opaque must be initialized before by | |
318 | the caller. If next_in is not Z_NULL and avail_in is large enough (the exact | |
319 | value depends on the compression method), inflateInit determines the | |
320 | compression method from the zlib header and allocates all data structures | |
321 | accordingly; otherwise the allocation will be deferred to the first call of | |
322 | inflate. If zalloc and zfree are set to Z_NULL, inflateInit updates them to | |
323 | use default allocation functions. | |
324 | ||
325 | inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough | |
326 | memory, Z_VERSION_ERROR if the zlib library version is incompatible with the | |
327 | version assumed by the caller. msg is set to null if there is no error | |
328 | message. inflateInit does not perform any decompression apart from reading | |
329 | the zlib header if present: this will be done by inflate(). (So next_in and | |
330 | avail_in may be modified, but next_out and avail_out are unchanged.) | |
331 | */ | |
332 | ||
333 | ||
a4019ec2 | 334 | ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush)); |
c801d85f KB |
335 | /* |
336 | inflate decompresses as much data as possible, and stops when the input | |
51dbdf87 VS |
337 | buffer becomes empty or the output buffer becomes full. It may introduce |
338 | some output latency (reading input without producing any output) except when | |
339 | forced to flush. | |
c801d85f KB |
340 | |
341 | The detailed semantics are as follows. inflate performs one or both of the | |
342 | following actions: | |
343 | ||
344 | - Decompress more input starting at next_in and update next_in and avail_in | |
345 | accordingly. If not all input can be processed (because there is not | |
346 | enough room in the output buffer), next_in is updated and processing | |
347 | will resume at this point for the next call of inflate(). | |
348 | ||
349 | - Provide more output starting at next_out and update next_out and avail_out | |
350 | accordingly. inflate() provides as much output as possible, until there | |
351 | is no more input data or no more space in the output buffer (see below | |
352 | about the flush parameter). | |
353 | ||
354 | Before the call of inflate(), the application should ensure that at least | |
355 | one of the actions is possible, by providing more input and/or consuming | |
356 | more output, and updating the next_* and avail_* values accordingly. | |
357 | The application can consume the uncompressed output when it wants, for | |
358 | example when the output buffer is full (avail_out == 0), or after each | |
359 | call of inflate(). If inflate returns Z_OK and with zero avail_out, it | |
360 | must be called again after making room in the output buffer because there | |
361 | might be more output pending. | |
362 | ||
51dbdf87 VS |
363 | The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, |
364 | Z_FINISH, or Z_BLOCK. Z_SYNC_FLUSH requests that inflate() flush as much | |
365 | output as possible to the output buffer. Z_BLOCK requests that inflate() stop | |
366 | if and when it get to the next deflate block boundary. When decoding the zlib | |
367 | or gzip format, this will cause inflate() to return immediately after the | |
368 | header and before the first block. When doing a raw inflate, inflate() will | |
369 | go ahead and process the first block, and will return when it gets to the end | |
370 | of that block, or when it runs out of data. | |
371 | ||
372 | The Z_BLOCK option assists in appending to or combining deflate streams. | |
373 | Also to assist in this, on return inflate() will set strm->data_type to the | |
374 | number of unused bits in the last byte taken from strm->next_in, plus 64 | |
375 | if inflate() is currently decoding the last block in the deflate stream, | |
376 | plus 128 if inflate() returned immediately after decoding an end-of-block | |
377 | code or decoding the complete header up to just before the first byte of the | |
378 | deflate stream. The end-of-block will not be indicated until all of the | |
379 | uncompressed data from that block has been written to strm->next_out. The | |
380 | number of unused bits may in general be greater than seven, except when | |
381 | bit 7 of data_type is set, in which case the number of unused bits will be | |
382 | less than eight. | |
c801d85f KB |
383 | |
384 | inflate() should normally be called until it returns Z_STREAM_END or an | |
385 | error. However if all decompression is to be performed in a single step | |
386 | (a single call of inflate), the parameter flush should be set to | |
387 | Z_FINISH. In this case all pending input is processed and all pending | |
388 | output is flushed; avail_out must be large enough to hold all the | |
389 | uncompressed data. (The size of the uncompressed data may have been saved | |
390 | by the compressor for this purpose.) The next operation on this stream must | |
391 | be inflateEnd to deallocate the decompression state. The use of Z_FINISH | |
51dbdf87 | 392 | is never required, but can be used to inform inflate that a faster approach |
c801d85f KB |
393 | may be used for the single inflate() call. |
394 | ||
51dbdf87 VS |
395 | In this implementation, inflate() always flushes as much output as |
396 | possible to the output buffer, and always uses the faster approach on the | |
397 | first call. So the only effect of the flush parameter in this implementation | |
398 | is on the return value of inflate(), as noted below, or when it returns early | |
399 | because Z_BLOCK is used. | |
400 | ||
401 | If a preset dictionary is needed after this call (see inflateSetDictionary | |
ba0052f3 | 402 | below), inflate sets strm->adler to the adler32 checksum of the dictionary |
51dbdf87 VS |
403 | chosen by the compressor and returns Z_NEED_DICT; otherwise it sets |
404 | strm->adler to the adler32 checksum of all output produced so far (that is, | |
405 | total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described | |
406 | below. At the end of the stream, inflate() checks that its computed adler32 | |
407 | checksum is equal to that saved by the compressor and returns Z_STREAM_END | |
408 | only if the checksum is correct. | |
409 | ||
410 | inflate() will decompress and check either zlib-wrapped or gzip-wrapped | |
411 | deflate data. The header type is detected automatically. Any information | |
412 | contained in the gzip header is not retained, so applications that need that | |
413 | information should instead use raw inflate, see inflateInit2() below, or | |
414 | inflateBack() and perform their own processing of the gzip header and | |
415 | trailer. | |
c801d85f KB |
416 | |
417 | inflate() returns Z_OK if some progress has been made (more input processed | |
418 | or more output produced), Z_STREAM_END if the end of the compressed data has | |
419 | been reached and all uncompressed output has been produced, Z_NEED_DICT if a | |
420 | preset dictionary is needed at this point, Z_DATA_ERROR if the input data was | |
51dbdf87 VS |
421 | corrupted (input stream not conforming to the zlib format or incorrect check |
422 | value), Z_STREAM_ERROR if the stream structure was inconsistent (for example | |
423 | if next_in or next_out was NULL), Z_MEM_ERROR if there was not enough memory, | |
424 | Z_BUF_ERROR if no progress is possible or if there was not enough room in the | |
425 | output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and | |
426 | inflate() can be called again with more input and more output space to | |
427 | continue decompressing. If Z_DATA_ERROR is returned, the application may then | |
428 | call inflateSync() to look for a good compression block if a partial recovery | |
429 | of the data is desired. | |
c801d85f KB |
430 | */ |
431 | ||
432 | ||
a4019ec2 | 433 | ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm)); |
c801d85f KB |
434 | /* |
435 | All dynamically allocated data structures for this stream are freed. | |
436 | This function discards any unprocessed input and does not flush any | |
437 | pending output. | |
438 | ||
439 | inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state | |
440 | was inconsistent. In the error case, msg may be set but then points to a | |
441 | static string (which must not be deallocated). | |
442 | */ | |
443 | ||
444 | /* Advanced functions */ | |
445 | ||
446 | /* | |
447 | The following functions are needed only in some special applications. | |
448 | */ | |
449 | ||
51dbdf87 | 450 | /* |
a4019ec2 | 451 | ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm, |
51dbdf87 VS |
452 | int level, |
453 | int method, | |
454 | int windowBits, | |
455 | int memLevel, | |
456 | int strategy)); | |
c801d85f KB |
457 | |
458 | This is another version of deflateInit with more compression options. The | |
459 | fields next_in, zalloc, zfree and opaque must be initialized before by | |
460 | the caller. | |
461 | ||
462 | The method parameter is the compression method. It must be Z_DEFLATED in | |
463 | this version of the library. | |
464 | ||
465 | The windowBits parameter is the base two logarithm of the window size | |
51dbdf87 | 466 | (the size of the history buffer). It should be in the range 8..15 for this |
c801d85f KB |
467 | version of the library. Larger values of this parameter result in better |
468 | compression at the expense of memory usage. The default value is 15 if | |
469 | deflateInit is used instead. | |
470 | ||
51dbdf87 VS |
471 | windowBits can also be -8..-15 for raw deflate. In this case, -windowBits |
472 | determines the window size. deflate() will then generate raw deflate data | |
473 | with no zlib header or trailer, and will not compute an adler32 check value. | |
474 | ||
475 | windowBits can also be greater than 15 for optional gzip encoding. Add | |
476 | 16 to windowBits to write a simple gzip header and trailer around the | |
477 | compressed data instead of a zlib wrapper. The gzip header will have no | |
478 | file name, no extra data, no comment, no modification time (set to zero), | |
ba0052f3 VS |
479 | no header crc, and the operating system will be set to 255 (unknown). If a |
480 | gzip stream is being written, strm->adler is a crc32 instead of an adler32. | |
51dbdf87 | 481 | |
c801d85f KB |
482 | The memLevel parameter specifies how much memory should be allocated |
483 | for the internal compression state. memLevel=1 uses minimum memory but | |
484 | is slow and reduces compression ratio; memLevel=9 uses maximum memory | |
485 | for optimal speed. The default value is 8. See zconf.h for total memory | |
486 | usage as a function of windowBits and memLevel. | |
487 | ||
488 | The strategy parameter is used to tune the compression algorithm. Use the | |
489 | value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a | |
51dbdf87 VS |
490 | filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no |
491 | string match), or Z_RLE to limit match distances to one (run-length | |
492 | encoding). Filtered data consists mostly of small values with a somewhat | |
493 | random distribution. In this case, the compression algorithm is tuned to | |
494 | compress them better. The effect of Z_FILTERED is to force more Huffman | |
495 | coding and less string matching; it is somewhat intermediate between | |
496 | Z_DEFAULT and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as fast as | |
497 | Z_HUFFMAN_ONLY, but give better compression for PNG image data. The strategy | |
498 | parameter only affects the compression ratio but not the correctness of the | |
499 | compressed output even if it is not set appropriately. | |
c801d85f KB |
500 | |
501 | deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough | |
502 | memory, Z_STREAM_ERROR if a parameter is invalid (such as an invalid | |
503 | method). msg is set to null if there is no error message. deflateInit2 does | |
504 | not perform any compression: this will be done by deflate(). | |
505 | */ | |
51dbdf87 | 506 | |
a4019ec2 | 507 | ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm, |
51dbdf87 VS |
508 | const Bytef *dictionary, |
509 | uInt dictLength)); | |
c801d85f KB |
510 | /* |
511 | Initializes the compression dictionary from the given byte sequence | |
512 | without producing any compressed output. This function must be called | |
a4019ec2 SC |
513 | immediately after deflateInit, deflateInit2 or deflateReset, before any |
514 | call of deflate. The compressor and decompressor must use exactly the same | |
c801d85f KB |
515 | dictionary (see inflateSetDictionary). |
516 | ||
517 | The dictionary should consist of strings (byte sequences) that are likely | |
518 | to be encountered later in the data to be compressed, with the most commonly | |
519 | used strings preferably put towards the end of the dictionary. Using a | |
520 | dictionary is most useful when the data to be compressed is short and can be | |
521 | predicted with good accuracy; the data can then be compressed better than | |
522 | with the default empty dictionary. | |
523 | ||
524 | Depending on the size of the compression data structures selected by | |
525 | deflateInit or deflateInit2, a part of the dictionary may in effect be | |
526 | discarded, for example if the dictionary is larger than the window size in | |
527 | deflate or deflate2. Thus the strings most likely to be useful should be | |
528 | put at the end of the dictionary, not at the front. | |
529 | ||
51dbdf87 | 530 | Upon return of this function, strm->adler is set to the adler32 value |
c801d85f | 531 | of the dictionary; the decompressor may later use this value to determine |
51dbdf87 | 532 | which dictionary has been used by the compressor. (The adler32 value |
c801d85f | 533 | applies to the whole dictionary even if only a subset of the dictionary is |
51dbdf87 VS |
534 | actually used by the compressor.) If a raw deflate was requested, then the |
535 | adler32 value is not computed and strm->adler is not set. | |
c801d85f KB |
536 | |
537 | deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a | |
538 | parameter is invalid (such as NULL dictionary) or the stream state is | |
539 | inconsistent (for example if deflate has already been called for this stream | |
540 | or if the compression method is bsort). deflateSetDictionary does not | |
541 | perform any compression: this will be done by deflate(). | |
542 | */ | |
543 | ||
a4019ec2 | 544 | ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest, |
51dbdf87 | 545 | z_streamp source)); |
c801d85f KB |
546 | /* |
547 | Sets the destination stream as a complete copy of the source stream. | |
548 | ||
549 | This function can be useful when several compression strategies will be | |
550 | tried, for example when there are several ways of pre-processing the input | |
551 | data with a filter. The streams that will be discarded should then be freed | |
552 | by calling deflateEnd. Note that deflateCopy duplicates the internal | |
553 | compression state which can be quite large, so this strategy is slow and | |
554 | can consume lots of memory. | |
555 | ||
556 | deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not | |
557 | enough memory, Z_STREAM_ERROR if the source stream state was inconsistent | |
558 | (such as zalloc being NULL). msg is left unchanged in both source and | |
559 | destination. | |
560 | */ | |
561 | ||
a4019ec2 | 562 | ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm)); |
c801d85f KB |
563 | /* |
564 | This function is equivalent to deflateEnd followed by deflateInit, | |
565 | but does not free and reallocate all the internal compression state. | |
566 | The stream will keep the same compression level and any other attributes | |
567 | that may have been set by deflateInit2. | |
568 | ||
569 | deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source | |
570 | stream state was inconsistent (such as zalloc or state being NULL). | |
571 | */ | |
572 | ||
a4019ec2 | 573 | ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm, |
51dbdf87 VS |
574 | int level, |
575 | int strategy)); | |
c801d85f KB |
576 | /* |
577 | Dynamically update the compression level and compression strategy. The | |
578 | interpretation of level and strategy is as in deflateInit2. This can be | |
579 | used to switch between compression and straight copy of the input data, or | |
580 | to switch to a different kind of input data requiring a different | |
581 | strategy. If the compression level is changed, the input available so far | |
582 | is compressed with the old level (and may be flushed); the new level will | |
583 | take effect only at the next call of deflate(). | |
584 | ||
585 | Before the call of deflateParams, the stream state must be set as for | |
586 | a call of deflate(), since the currently available input may have to | |
587 | be compressed and flushed. In particular, strm->avail_out must be non-zero. | |
588 | ||
589 | deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source | |
590 | stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR | |
591 | if strm->avail_out was zero. | |
592 | */ | |
593 | ||
51dbdf87 VS |
594 | ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm, |
595 | uLong sourceLen)); | |
596 | /* | |
597 | deflateBound() returns an upper bound on the compressed size after | |
598 | deflation of sourceLen bytes. It must be called after deflateInit() | |
599 | or deflateInit2(). This would be used to allocate an output buffer | |
600 | for deflation in a single pass, and so would be called before deflate(). | |
601 | */ | |
602 | ||
603 | ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm, | |
604 | int bits, | |
605 | int value)); | |
606 | /* | |
607 | deflatePrime() inserts bits in the deflate output stream. The intent | |
608 | is that this function is used to start off the deflate output with the | |
609 | bits leftover from a previous deflate stream when appending to it. As such, | |
610 | this function can only be used for raw deflate, and must be used before the | |
611 | first deflate() call after a deflateInit2() or deflateReset(). bits must be | |
612 | less than or equal to 16, and that many of the least significant bits of | |
613 | value will be inserted in the output. | |
614 | ||
615 | deflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source | |
616 | stream state was inconsistent. | |
617 | */ | |
618 | ||
619 | /* | |
a4019ec2 | 620 | ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm, |
51dbdf87 | 621 | int windowBits)); |
c801d85f KB |
622 | |
623 | This is another version of inflateInit with an extra parameter. The | |
624 | fields next_in, avail_in, zalloc, zfree and opaque must be initialized | |
625 | before by the caller. | |
626 | ||
627 | The windowBits parameter is the base two logarithm of the maximum window | |
628 | size (the size of the history buffer). It should be in the range 8..15 for | |
629 | this version of the library. The default value is 15 if inflateInit is used | |
51dbdf87 VS |
630 | instead. windowBits must be greater than or equal to the windowBits value |
631 | provided to deflateInit2() while compressing, or it must be equal to 15 if | |
632 | deflateInit2() was not used. If a compressed stream with a larger window | |
633 | size is given as input, inflate() will return with the error code | |
634 | Z_DATA_ERROR instead of trying to allocate a larger window. | |
635 | ||
636 | windowBits can also be -8..-15 for raw inflate. In this case, -windowBits | |
637 | determines the window size. inflate() will then process raw deflate data, | |
638 | not looking for a zlib or gzip header, not generating a check value, and not | |
639 | looking for any check values for comparison at the end of the stream. This | |
640 | is for use with other formats that use the deflate compressed data format | |
641 | such as zip. Those formats provide their own check values. If a custom | |
642 | format is developed using the raw deflate format for compressed data, it is | |
643 | recommended that a check value such as an adler32 or a crc32 be applied to | |
644 | the uncompressed data as is done in the zlib, gzip, and zip formats. For | |
645 | most applications, the zlib format should be used as is. Note that comments | |
646 | above on the use in deflateInit2() applies to the magnitude of windowBits. | |
647 | ||
648 | windowBits can also be greater than 15 for optional gzip decoding. Add | |
649 | 32 to windowBits to enable zlib and gzip decoding with automatic header | |
650 | detection, or add 16 to decode only the gzip format (the zlib format will | |
ba0052f3 VS |
651 | return a Z_DATA_ERROR. If a gzip stream is being decoded, strm->adler is |
652 | a crc32 instead of an adler32. | |
51dbdf87 VS |
653 | |
654 | inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough | |
c801d85f KB |
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 | ||
a4019ec2 | 662 | ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm, |
51dbdf87 VS |
663 | const Bytef *dictionary, |
664 | uInt dictLength)); | |
c801d85f KB |
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 | |
51dbdf87 | 669 | can be determined from the adler32 value returned by this call of |
c801d85f KB |
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 | |
51dbdf87 | 676 | expected one (incorrect adler32 value). inflateSetDictionary does not |
c801d85f KB |
677 | perform any decompression: this will be done by subsequent calls of |
678 | inflate(). | |
679 | */ | |
680 | ||
a4019ec2 | 681 | ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm)); |
51dbdf87 | 682 | /* |
c801d85f KB |
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 | ||
51dbdf87 VS |
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 | ||
a4019ec2 | 712 | ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm)); |
c801d85f KB |
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 | ||
51dbdf87 VS |
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 | ||
c801d85f KB |
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 | ||
a4019ec2 | 876 | ZEXTERN int ZEXPORT compress OF((Bytef *dest, uLongf *destLen, |
51dbdf87 | 877 | const Bytef *source, uLong sourceLen)); |
c801d85f KB |
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 | |
51dbdf87 VS |
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 | |
c801d85f KB |
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 | ||
a4019ec2 | 891 | ZEXTERN int ZEXPORT compress2 OF((Bytef *dest, uLongf *destLen, |
51dbdf87 VS |
892 | const Bytef *source, uLong sourceLen, |
893 | int level)); | |
c801d85f KB |
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 | |
51dbdf87 VS |
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. | |
c801d85f KB |
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 | ||
51dbdf87 VS |
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 | ||
a4019ec2 | 914 | ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen, |
51dbdf87 | 915 | const Bytef *source, uLong sourceLen)); |
c801d85f KB |
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 | |
51dbdf87 | 929 | buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete. |
c801d85f KB |
930 | */ |
931 | ||
932 | ||
933 | typedef voidp gzFile; | |
934 | ||
a4019ec2 | 935 | ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode)); |
c801d85f KB |
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 | |
51dbdf87 VS |
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.) | |
c801d85f KB |
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 | ||
a4019ec2 | 952 | ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode)); |
c801d85f KB |
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 | ||
a4019ec2 | 965 | ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy)); |
c801d85f KB |
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 | ||
a4019ec2 | 973 | ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len)); |
c801d85f KB |
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 | ||
51dbdf87 VS |
981 | ZEXTERN int ZEXPORT gzwrite OF((gzFile file, |
982 | voidpc buf, unsigned len)); | |
c801d85f KB |
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 | ||
a4019ec2 | 989 | ZEXTERN int ZEXPORTVA gzprintf OF((gzFile file, const char *format, ...)); |
c801d85f KB |
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 | |
51dbdf87 VS |
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. | |
c801d85f KB |
1000 | */ |
1001 | ||
a4019ec2 | 1002 | ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s)); |
c801d85f KB |
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 | ||
a4019ec2 | 1009 | ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len)); |
c801d85f KB |
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 | ||
a4019ec2 | 1018 | ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c)); |
c801d85f KB |
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 | ||
a4019ec2 | 1024 | ZEXTERN int ZEXPORT gzgetc OF((gzFile file)); |
c801d85f KB |
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 | ||
51dbdf87 VS |
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 | ||
a4019ec2 | 1040 | ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush)); |
c801d85f KB |
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 | ||
a4019ec2 | 1050 | ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file, |
51dbdf87 VS |
1051 | z_off_t offset, int whence)); |
1052 | /* | |
a4019ec2 SC |
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 | |
c801d85f KB |
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 | ||
a4019ec2 | 1068 | ZEXTERN int ZEXPORT gzrewind OF((gzFile file)); |
c801d85f KB |
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 | ||
a4019ec2 | 1075 | ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file)); |
c801d85f KB |
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 | ||
a4019ec2 | 1084 | ZEXTERN int ZEXPORT gzeof OF((gzFile file)); |
c801d85f KB |
1085 | /* |
1086 | Returns 1 when EOF has previously been detected reading the given | |
1087 | input stream, otherwise zero. | |
1088 | */ | |
1089 | ||
a4019ec2 | 1090 | ZEXTERN int ZEXPORT gzclose OF((gzFile file)); |
c801d85f KB |
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 | ||
a4019ec2 | 1097 | ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum)); |
c801d85f KB |
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 | ||
51dbdf87 VS |
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 | ||
c801d85f KB |
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 | ||
a4019ec2 | 1121 | ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len)); |
c801d85f KB |
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 | ||
a4019ec2 | 1138 | ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len)); |
c801d85f KB |
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 | */ | |
a4019ec2 | 1160 | ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level, |
51dbdf87 | 1161 | const char *version, int stream_size)); |
a4019ec2 | 1162 | ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm, |
51dbdf87 | 1163 | const char *version, int stream_size)); |
a4019ec2 | 1164 | ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method, |
51dbdf87 VS |
1165 | int windowBits, int memLevel, |
1166 | int strategy, const char *version, | |
1167 | int stream_size)); | |
a4019ec2 | 1168 | ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits, |
51dbdf87 VS |
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)); | |
c801d85f KB |
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)) | |
51dbdf87 VS |
1183 | #define inflateBackInit(strm, windowBits, window) \ |
1184 | inflateBackInit_((strm), (windowBits), (window), \ | |
1185 | ZLIB_VERSION, sizeof(z_stream)) | |
c801d85f KB |
1186 | |
1187 | ||
51dbdf87 | 1188 | #if !defined(ZUTIL_H) && !defined(NO_DUMMY_DECL) |
c801d85f KB |
1189 | struct internal_state {int dummy;}; /* hack for buggy compilers */ |
1190 | #endif | |
1191 | ||
ba0052f3 | 1192 | ZEXTERN const char * ZEXPORT zError OF((int)); |
a4019ec2 SC |
1193 | ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp z)); |
1194 | ZEXTERN const uLongf * ZEXPORT get_crc_table OF((void)); | |
c801d85f KB |
1195 | |
1196 | #ifdef __cplusplus | |
1197 | } | |
1198 | #endif | |
1199 | ||
51dbdf87 | 1200 | #endif /* ZLIB_H */ |