00001 /* zlib.h -- interface of the 'zlib' general purpose compression library 00002 version 1.1.1, Feb 27th, 1998 00003 00004 Copyright (C) 1995-1998 Jean-loup Gailly and Mark Adler 00005 00006 This software is provided 'as-is', without any express or implied 00007 warranty. In no event will the authors be held liable for any damages 00008 arising from the use of this software. 00009 00010 Permission is granted to anyone to use this software for any purpose, 00011 including commercial applications, and to alter it and redistribute it 00012 freely, subject to the following restrictions: 00013 00014 1. The origin of this software must not be misrepresented; you must not 00015 claim that you wrote the original software. If you use this software 00016 in a product, an acknowledgment in the product documentation would be 00017 appreciated but is not required. 00018 2. Altered source versions must be plainly marked as such, and must not be 00019 misrepresented as being the original software. 00020 3. This notice may not be removed or altered from any source distribution. 00021 00022 Jean-loup Gailly Mark Adler 00023 jloup@gzip.org madler@alumni.caltech.edu 00024 00025 00026 The data format used by the zlib library is described by RFCs (Request for 00027 Comments) 1950 to 1952 in the files ftp://ds.internic.net/rfc/rfc1950.txt 00028 (zlib format), rfc1951.txt (deflate format) and rfc1952.txt (gzip format). 00029 */ 00030 00031 #ifndef _ZLIB_H 00032 #define _ZLIB_H 00033 00034 #ifdef __cplusplus 00035 extern "C" { 00036 #endif 00037 00038 #include "zconf.h" 00039 00040 #define ZLIB_VERSION "1.1.1" 00041 00042 /* 00043 The 'zlib' compression library provides in-memory compression and 00044 decompression functions, including integrity checks of the uncompressed 00045 data. This version of the library supports only one compression method 00046 (deflation) but other algorithms will be added later and will have the same 00047 stream interface. 00048 00049 Compression can be done in a single step if the buffers are large 00050 enough (for example if an input file is mmap'ed), or can be done by 00051 repeated calls of the compression function. In the latter case, the 00052 application must provide more input and/or consume the output 00053 (providing more output space) before each call. 00054 00055 The library also supports reading and writing files in gzip (.gz) format 00056 with an interface similar to that of stdio. 00057 00058 The library does not install any signal handler. The decoder checks 00059 the consistency of the compressed data, so the library should never 00060 crash even in case of corrupted input. 00061 */ 00062 00063 typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size)); 00064 typedef void (*free_func) OF((voidpf opaque, voidpf address)); 00065 00066 struct internal_state; 00067 00068 typedef struct z_stream_s { 00069 Bytef *next_in; /* next input byte */ 00070 uInt avail_in; /* number of bytes available at next_in */ 00071 uLong total_in; /* total nb of input bytes read so far */ 00072 00073 Bytef *next_out; /* next output byte should be put there */ 00074 uInt avail_out; /* remaining free space at next_out */ 00075 uLong total_out; /* total nb of bytes output so far */ 00076 00077 char *msg; /* last error message, NULL if no error */ 00078 struct internal_state FAR *state; /* not visible by applications */ 00079 00080 alloc_func zalloc; /* used to allocate the internal state */ 00081 free_func zfree; /* used to free the internal state */ 00082 voidpf opaque; /* private data object passed to zalloc and zfree */ 00083 00084 int data_type; /* best guess about the data type: ascii or binary */ 00085 uLong adler; /* adler32 value of the uncompressed data */ 00086 uLong reserved; /* reserved for future use */ 00087 } z_stream; 00088 00089 typedef z_stream FAR *z_streamp; 00090 00091 /* 00092 The application must update next_in and avail_in when avail_in has 00093 dropped to zero. It must update next_out and avail_out when avail_out 00094 has dropped to zero. The application must initialize zalloc, zfree and 00095 opaque before calling the init function. All other fields are set by the 00096 compression library and must not be updated by the application. 00097 00098 The opaque value provided by the application will be passed as the first 00099 parameter for calls of zalloc and zfree. This can be useful for custom 00100 memory management. The compression library attaches no meaning to the 00101 opaque value. 00102 00103 zalloc must return Z_NULL if there is not enough memory for the object. 00104 If zlib is used in a multi-threaded application, zalloc and zfree must be 00105 thread safe. 00106 00107 On 16-bit systems, the functions zalloc and zfree must be able to allocate 00108 exactly 65536 bytes, but will not be required to allocate more than this 00109 if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, 00110 pointers returned by zalloc for objects of exactly 65536 bytes *must* 00111 have their offset normalized to zero. The default allocation function 00112 provided by this library ensures this (see zutil.c). To reduce memory 00113 requirements and avoid any allocation of 64K objects, at the expense of 00114 compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h). 00115 00116 The fields total_in and total_out can be used for statistics or 00117 progress reports. After compression, total_in holds the total size of 00118 the uncompressed data and may be saved for use in the decompressor 00119 (particularly if the decompressor wants to decompress everything in 00120 a single step). 00121 */ 00122 00123 /* constants */ 00124 00125 #define Z_NO_FLUSH 0 00126 #define Z_PARTIAL_FLUSH 1 /* will be removed, use Z_SYNC_FLUSH instead */ 00127 #define Z_SYNC_FLUSH 2 00128 #define Z_FULL_FLUSH 3 00129 #define Z_FINISH 4 00130 /* Allowed flush values; see deflate() below for details */ 00131 00132 #define Z_OK 0 00133 #define Z_STREAM_END 1 00134 #define Z_NEED_DICT 2 00135 #define Z_ERRNO (-1) 00136 #define Z_STREAM_ERROR (-2) 00137 #define Z_DATA_ERROR (-3) 00138 #define Z_MEM_ERROR (-4) 00139 #define Z_BUF_ERROR (-5) 00140 #define Z_VERSION_ERROR (-6) 00141 /* Return codes for the compression/decompression functions. Negative 00142 * values are errors, positive values are used for special but normal events. 00143 */ 00144 00145 #define Z_NO_COMPRESSION 0 00146 #define Z_BEST_SPEED 1 00147 #define Z_BEST_COMPRESSION 9 00148 #define Z_DEFAULT_COMPRESSION (-1) 00149 /* compression levels */ 00150 00151 #define Z_FILTERED 1 00152 #define Z_HUFFMAN_ONLY 2 00153 #define Z_DEFAULT_STRATEGY 0 00154 /* compression strategy; see deflateInit2() below for details */ 00155 00156 #define Z_BINARY 0 00157 #define Z_ASCII 1 00158 #define Z_UNKNOWN 2 00159 /* Possible values of the data_type field */ 00160 00161 #define Z_DEFLATED 8 00162 /* The deflate compression method (the only one supported in this version) */ 00163 00164 #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */ 00165 00166 #define zlib_version zlibVersion() 00167 /* for compatibility with versions < 1.0.2 */ 00168 00169 /* basic functions */ 00170 00171 extern const char * ZEXPORT zlibVersion OF((void)); 00172 /* The application can compare zlibVersion and ZLIB_VERSION for consistency. 00173 If the first character differs, the library code actually used is 00174 not compatible with the zlib.h header file used by the application. 00175 This check is automatically made by deflateInit and inflateInit. 00176 */ 00177 00178 /* 00179 extern int ZEXPORT deflateInit OF((z_streamp strm, int level)); 00180 00181 Initializes the internal stream state for compression. The fields 00182 zalloc, zfree and opaque must be initialized before by the caller. 00183 If zalloc and zfree are set to Z_NULL, deflateInit updates them to 00184 use default allocation functions. 00185 00186 The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9: 00187 1 gives best speed, 9 gives best compression, 0 gives no compression at 00188 all (the input data is simply copied a block at a time). 00189 Z_DEFAULT_COMPRESSION requests a default compromise between speed and 00190 compression (currently equivalent to level 6). 00191 00192 deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not 00193 enough memory, Z_STREAM_ERROR if level is not a valid compression level, 00194 Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible 00195 with the version assumed by the caller (ZLIB_VERSION). 00196 msg is set to null if there is no error message. deflateInit does not 00197 perform any compression: this will be done by deflate(). 00198 */ 00199 00200 00201 extern int ZEXPORT deflate OF((z_streamp strm, int flush)); 00202 /* 00203 deflate compresses as much data as possible, and stops when the input 00204 buffer becomes empty or the output buffer becomes full. It may introduce some 00205 output latency (reading input without producing any output) except when 00206 forced to flush. 00207 00208 The detailed semantics are as follows. deflate performs one or both of the 00209 following actions: 00210 00211 - Compress more input starting at next_in and update next_in and avail_in 00212 accordingly. If not all input can be processed (because there is not 00213 enough room in the output buffer), next_in and avail_in are updated and 00214 processing will resume at this point for the next call of deflate(). 00215 00216 - Provide more output starting at next_out and update next_out and avail_out 00217 accordingly. This action is forced if the parameter flush is non zero. 00218 Forcing flush frequently degrades the compression ratio, so this parameter 00219 should be set only when necessary (in interactive applications). 00220 Some output may be provided even if flush is not set. 00221 00222 Before the call of deflate(), the application should ensure that at least 00223 one of the actions is possible, by providing more input and/or consuming 00224 more output, and updating avail_in or avail_out accordingly; avail_out 00225 should never be zero before the call. The application can consume the 00226 compressed output when it wants, for example when the output buffer is full 00227 (avail_out == 0), or after each call of deflate(). If deflate returns Z_OK 00228 and with zero avail_out, it must be called again after making room in the 00229 output buffer because there might be more output pending. 00230 00231 If the parameter flush is set to Z_SYNC_FLUSH, all pending output is 00232 flushed to the output buffer and the output is aligned on a byte boundary, so 00233 that the decompressor can get all input data available so far. (In particular 00234 avail_in is zero after the call if enough output space has been provided 00235 before the call.) Flushing may degrade compression for some compression 00236 algorithms and so it should be used only when necessary. 00237 00238 If flush is set to Z_FULL_FLUSH, all output is flushed as with 00239 Z_SYNC_FLUSH, and the compression state is reset so that decompression can 00240 restart from this point if previous compressed data has been damaged or if 00241 random access is desired. Using Z_FULL_FLUSH too often can seriously degrade 00242 the compression. 00243 00244 If deflate returns with avail_out == 0, this function must be called again 00245 with the same value of the flush parameter and more output space (updated 00246 avail_out), until the flush is complete (deflate returns with non-zero 00247 avail_out). 00248 00249 If the parameter flush is set to Z_FINISH, pending input is processed, 00250 pending output is flushed and deflate returns with Z_STREAM_END if there 00251 was enough output space; if deflate returns with Z_OK, this function must be 00252 called again with Z_FINISH and more output space (updated avail_out) but no 00253 more input data, until it returns with Z_STREAM_END or an error. After 00254 deflate has returned Z_STREAM_END, the only possible operations on the 00255 stream are deflateReset or deflateEnd. 00256 00257 Z_FINISH can be used immediately after deflateInit if all the compression 00258 is to be done in a single step. In this case, avail_out must be at least 00259 0.1% larger than avail_in plus 12 bytes. If deflate does not return 00260 Z_STREAM_END, then it must be called again as described above. 00261 00262 deflate() sets strm->adler to the adler32 checksum of all input read 00263 so far (that is, total_in bytes). 00264 00265 deflate() may update data_type if it can make a good guess about 00266 the input data type (Z_ASCII or Z_BINARY). In doubt, the data is considered 00267 binary. This field is only for information purposes and does not affect 00268 the compression algorithm in any manner. 00269 00270 deflate() returns Z_OK if some progress has been made (more input 00271 processed or more output produced), Z_STREAM_END if all input has been 00272 consumed and all output has been produced (only when flush is set to 00273 Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example 00274 if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible. 00275 */ 00276 00277 00278 extern int ZEXPORT deflateEnd OF((z_streamp strm)); 00279 /* 00280 All dynamically allocated data structures for this stream are freed. 00281 This function discards any unprocessed input and does not flush any 00282 pending output. 00283 00284 deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the 00285 stream state was inconsistent, Z_DATA_ERROR if the stream was freed 00286 prematurely (some input or output was discarded). In the error case, 00287 msg may be set but then points to a static string (which must not be 00288 deallocated). 00289 */ 00290 00291 00292 /* 00293 extern int ZEXPORT inflateInit OF((z_streamp strm)); 00294 00295 Initializes the internal stream state for decompression. The fields 00296 next_in, avail_in, zalloc, zfree and opaque must be initialized before by 00297 the caller. If next_in is not Z_NULL and avail_in is large enough (the exact 00298 value depends on the compression method), inflateInit determines the 00299 compression method from the zlib header and allocates all data structures 00300 accordingly; otherwise the allocation will be deferred to the first call of 00301 inflate. If zalloc and zfree are set to Z_NULL, inflateInit updates them to 00302 use default allocation functions. 00303 00304 inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough 00305 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the 00306 version assumed by the caller. msg is set to null if there is no error 00307 message. inflateInit does not perform any decompression apart from reading 00308 the zlib header if present: this will be done by inflate(). (So next_in and 00309 avail_in may be modified, but next_out and avail_out are unchanged.) 00310 */ 00311 00312 00313 extern int ZEXPORT inflate OF((z_streamp strm, int flush)); 00314 /* 00315 inflate decompresses as much data as possible, and stops when the input 00316 buffer becomes empty or the output buffer becomes full. It may some 00317 introduce some output latency (reading input without producing any output) 00318 except when forced to flush. 00319 00320 The detailed semantics are as follows. inflate performs one or both of the 00321 following actions: 00322 00323 - Decompress more input starting at next_in and update next_in and avail_in 00324 accordingly. If not all input can be processed (because there is not 00325 enough room in the output buffer), next_in is updated and processing 00326 will resume at this point for the next call of inflate(). 00327 00328 - Provide more output starting at next_out and update next_out and avail_out 00329 accordingly. inflate() provides as much output as possible, until there 00330 is no more input data or no more space in the output buffer (see below 00331 about the flush parameter). 00332 00333 Before the call of inflate(), the application should ensure that at least 00334 one of the actions is possible, by providing more input and/or consuming 00335 more output, and updating the next_* and avail_* values accordingly. 00336 The application can consume the uncompressed output when it wants, for 00337 example when the output buffer is full (avail_out == 0), or after each 00338 call of inflate(). If inflate returns Z_OK and with zero avail_out, it 00339 must be called again after making room in the output buffer because there 00340 might be more output pending. 00341 00342 If the parameter flush is set to Z_SYNC_FLUSH, inflate flushes as much 00343 output as possible to the output buffer. The flushing behavior of inflate is 00344 not specified for values of the flush parameter other than Z_SYNC_FLUSH 00345 and Z_FINISH, but the current implementation actually flushes as much output 00346 as possible anyway. 00347 00348 inflate() should normally be called until it returns Z_STREAM_END or an 00349 error. However if all decompression is to be performed in a single step 00350 (a single call of inflate), the parameter flush should be set to 00351 Z_FINISH. In this case all pending input is processed and all pending 00352 output is flushed; avail_out must be large enough to hold all the 00353 uncompressed data. (The size of the uncompressed data may have been saved 00354 by the compressor for this purpose.) The next operation on this stream must 00355 be inflateEnd to deallocate the decompression state. The use of Z_FINISH 00356 is never required, but can be used to inform inflate that a faster routine 00357 may be used for the single inflate() call. 00358 00359 If a preset dictionary is needed at this point (see inflateSetDictionary 00360 below), inflate sets strm-adler to the adler32 checksum of the 00361 dictionary chosen by the compressor and returns Z_NEED_DICT; otherwise 00362 it sets strm->adler to the adler32 checksum of all output produced 00363 so far (that is, total_out bytes) and returns Z_OK, Z_STREAM_END or 00364 an error code as described below. At the end of the stream, inflate() 00365 checks that its computed adler32 checksum is equal to that saved by the 00366 compressor and returns Z_STREAM_END only if the checksum is correct. 00367 00368 inflate() returns Z_OK if some progress has been made (more input processed 00369 or more output produced), Z_STREAM_END if the end of the compressed data has 00370 been reached and all uncompressed output has been produced, Z_NEED_DICT if a 00371 preset dictionary is needed at this point, Z_DATA_ERROR if the input data was 00372 corrupted (input stream not conforming to the zlib format or incorrect 00373 adler32 checksum), Z_STREAM_ERROR if the stream structure was inconsistent 00374 (for example if next_in or next_out was NULL), Z_MEM_ERROR if there was not 00375 enough memory, Z_BUF_ERROR if no progress is possible or if there was not 00376 enough room in the output buffer when Z_FINISH is used. In the Z_DATA_ERROR 00377 case, the application may then call inflateSync to look for a good 00378 compression block. 00379 */ 00380 00381 00382 extern int ZEXPORT inflateEnd OF((z_streamp strm)); 00383 /* 00384 All dynamically allocated data structures for this stream are freed. 00385 This function discards any unprocessed input and does not flush any 00386 pending output. 00387 00388 inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state 00389 was inconsistent. In the error case, msg may be set but then points to a 00390 static string (which must not be deallocated). 00391 */ 00392 00393 /* Advanced functions */ 00394 00395 /* 00396 The following functions are needed only in some special applications. 00397 */ 00398 00399 /* 00400 extern int ZEXPORT deflateInit2 OF((z_streamp strm, 00401 int level, 00402 int method, 00403 int windowBits, 00404 int memLevel, 00405 int strategy)); 00406 00407 This is another version of deflateInit with more compression options. The 00408 fields next_in, zalloc, zfree and opaque must be initialized before by 00409 the caller. 00410 00411 The method parameter is the compression method. It must be Z_DEFLATED in 00412 this version of the library. 00413 00414 The windowBits parameter is the base two logarithm of the window size 00415 (the size of the history buffer). It should be in the range 8..15 for this 00416 version of the library. Larger values of this parameter result in better 00417 compression at the expense of memory usage. The default value is 15 if 00418 deflateInit is used instead. 00419 00420 The memLevel parameter specifies how much memory should be allocated 00421 for the internal compression state. memLevel=1 uses minimum memory but 00422 is slow and reduces compression ratio; memLevel=9 uses maximum memory 00423 for optimal speed. The default value is 8. See zconf.h for total memory 00424 usage as a function of windowBits and memLevel. 00425 00426 The strategy parameter is used to tune the compression algorithm. Use the 00427 value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a 00428 filter (or predictor), or Z_HUFFMAN_ONLY to force Huffman encoding only (no 00429 string match). Filtered data consists mostly of small values with a 00430 somewhat random distribution. In this case, the compression algorithm is 00431 tuned to compress them better. The effect of Z_FILTERED is to force more 00432 Huffman coding and less string matching; it is somewhat intermediate 00433 between Z_DEFAULT and Z_HUFFMAN_ONLY. The strategy parameter only affects 00434 the compression ratio but not the correctness of the compressed output even 00435 if it is not set appropriately. 00436 00437 deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 00438 memory, Z_STREAM_ERROR if a parameter is invalid (such as an invalid 00439 method). msg is set to null if there is no error message. deflateInit2 does 00440 not perform any compression: this will be done by deflate(). 00441 */ 00442 00443 extern int ZEXPORT deflateSetDictionary OF((z_streamp strm, 00444 const Bytef *dictionary, 00445 uInt dictLength)); 00446 /* 00447 Initializes the compression dictionary from the given byte sequence 00448 without producing any compressed output. This function must be called 00449 immediately after deflateInit or deflateInit2, before any call of 00450 deflate. The compressor and decompressor must use exactly the same 00451 dictionary (see inflateSetDictionary). 00452 00453 The dictionary should consist of strings (byte sequences) that are likely 00454 to be encountered later in the data to be compressed, with the most commonly 00455 used strings preferably put towards the end of the dictionary. Using a 00456 dictionary is most useful when the data to be compressed is short and can be 00457 predicted with good accuracy; the data can then be compressed better than 00458 with the default empty dictionary. 00459 00460 Depending on the size of the compression data structures selected by 00461 deflateInit or deflateInit2, a part of the dictionary may in effect be 00462 discarded, for example if the dictionary is larger than the window size in 00463 deflate or deflate2. Thus the strings most likely to be useful should be 00464 put at the end of the dictionary, not at the front. 00465 00466 Upon return of this function, strm->adler is set to the Adler32 value 00467 of the dictionary; the decompressor may later use this value to determine 00468 which dictionary has been used by the compressor. (The Adler32 value 00469 applies to the whole dictionary even if only a subset of the dictionary is 00470 actually used by the compressor.) 00471 00472 deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a 00473 parameter is invalid (such as NULL dictionary) or the stream state is 00474 inconsistent (for example if deflate has already been called for this stream 00475 or if the compression method is bsort). deflateSetDictionary does not 00476 perform any compression: this will be done by deflate(). 00477 */ 00478 00479 extern int ZEXPORT deflateCopy OF((z_streamp dest, 00480 z_streamp source)); 00481 /* 00482 Sets the destination stream as a complete copy of the source stream. 00483 00484 This function can be useful when several compression strategies will be 00485 tried, for example when there are several ways of pre-processing the input 00486 data with a filter. The streams that will be discarded should then be freed 00487 by calling deflateEnd. Note that deflateCopy duplicates the internal 00488 compression state which can be quite large, so this strategy is slow and 00489 can consume lots of memory. 00490 00491 deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not 00492 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent 00493 (such as zalloc being NULL). msg is left unchanged in both source and 00494 destination. 00495 */ 00496 00497 extern int ZEXPORT deflateReset OF((z_streamp strm)); 00498 /* 00499 This function is equivalent to deflateEnd followed by deflateInit, 00500 but does not free and reallocate all the internal compression state. 00501 The stream will keep the same compression level and any other attributes 00502 that may have been set by deflateInit2. 00503 00504 deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source 00505 stream state was inconsistent (such as zalloc or state being NULL). 00506 */ 00507 00508 extern int ZEXPORT deflateParams OF((z_streamp strm, int level, int strategy)); 00509 /* 00510 Dynamically update the compression level and compression strategy. The 00511 interpretation of level and strategy is as in deflateInit2. This can be 00512 used to switch between compression and straight copy of the input data, or 00513 to switch to a different kind of input data requiring a different 00514 strategy. If the compression level is changed, the input available so far 00515 is compressed with the old level (and may be flushed); the new level will 00516 take effect only at the next call of deflate(). 00517 00518 Before the call of deflateParams, the stream state must be set as for 00519 a call of deflate(), since the currently available input may have to 00520 be compressed and flushed. In particular, strm->avail_out must be non-zero. 00521 00522 deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source 00523 stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR 00524 if strm->avail_out was zero. 00525 */ 00526 00527 /* 00528 extern int ZEXPORT inflateInit2 OF((z_streamp strm, 00529 int windowBits)); 00530 00531 This is another version of inflateInit with an extra parameter. The 00532 fields next_in, avail_in, zalloc, zfree and opaque must be initialized 00533 before by the caller. 00534 00535 The windowBits parameter is the base two logarithm of the maximum window 00536 size (the size of the history buffer). It should be in the range 8..15 for 00537 this version of the library. The default value is 15 if inflateInit is used 00538 instead. If a compressed stream with a larger window size is given as 00539 input, inflate() will return with the error code Z_DATA_ERROR instead of 00540 trying to allocate a larger window. 00541 00542 inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 00543 memory, Z_STREAM_ERROR if a parameter is invalid (such as a negative 00544 memLevel). msg is set to null if there is no error message. inflateInit2 00545 does not perform any decompression apart from reading the zlib header if 00546 present: this will be done by inflate(). (So next_in and avail_in may be 00547 modified, but next_out and avail_out are unchanged.) 00548 */ 00549 00550 extern int ZEXPORT inflateSetDictionary OF((z_streamp strm, 00551 const Bytef *dictionary, 00552 uInt dictLength)); 00553 /* 00554 Initializes the decompression dictionary from the given uncompressed byte 00555 sequence. This function must be called immediately after a call of inflate 00556 if this call returned Z_NEED_DICT. The dictionary chosen by the compressor 00557 can be determined from the Adler32 value returned by this call of 00558 inflate. The compressor and decompressor must use exactly the same 00559 dictionary (see deflateSetDictionary). 00560 00561 inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a 00562 parameter is invalid (such as NULL dictionary) or the stream state is 00563 inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the 00564 expected one (incorrect Adler32 value). inflateSetDictionary does not 00565 perform any decompression: this will be done by subsequent calls of 00566 inflate(). 00567 */ 00568 00569 extern int ZEXPORT inflateSync OF((z_streamp strm)); 00570 /* 00571 Skips invalid compressed data until a full flush point (see above the 00572 description of deflate with Z_FULL_FLUSH) can be found, or until all 00573 available input is skipped. No output is provided. 00574 00575 inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR 00576 if no more input was provided, Z_DATA_ERROR if no flush point has been found, 00577 or Z_STREAM_ERROR if the stream structure was inconsistent. In the success 00578 case, the application may save the current current value of total_in which 00579 indicates where valid compressed data was found. In the error case, the 00580 application may repeatedly call inflateSync, providing more input each time, 00581 until success or end of the input data. 00582 */ 00583 00584 extern int ZEXPORT inflateReset OF((z_streamp strm)); 00585 /* 00586 This function is equivalent to inflateEnd followed by inflateInit, 00587 but does not free and reallocate all the internal decompression state. 00588 The stream will keep attributes that may have been set by inflateInit2. 00589 00590 inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source 00591 stream state was inconsistent (such as zalloc or state being NULL). 00592 */ 00593 00594 00595 /* utility functions */ 00596 00597 /* 00598 The following utility functions are implemented on top of the 00599 basic stream-oriented functions. To simplify the interface, some 00600 default options are assumed (compression level and memory usage, 00601 standard memory allocation functions). The source code of these 00602 utility functions can easily be modified if you need special options. 00603 */ 00604 00605 extern int ZEXPORT compress OF((Bytef *dest, uLongf *destLen, 00606 const Bytef *source, uLong sourceLen)); 00607 /* 00608 Compresses the source buffer into the destination buffer. sourceLen is 00609 the byte length of the source buffer. Upon entry, destLen is the total 00610 size of the destination buffer, which must be at least 0.1% larger than 00611 sourceLen plus 12 bytes. Upon exit, destLen is the actual size of the 00612 compressed buffer. 00613 This function can be used to compress a whole file at once if the 00614 input file is mmap'ed. 00615 compress returns Z_OK if success, Z_MEM_ERROR if there was not 00616 enough memory, Z_BUF_ERROR if there was not enough room in the output 00617 buffer. 00618 */ 00619 00620 extern int ZEXPORT compress2 OF((Bytef *dest, uLongf *destLen, 00621 const Bytef *source, uLong sourceLen, 00622 int level)); 00623 /* 00624 Compresses the source buffer into the destination buffer. The level 00625 parameter has the same meaning as in deflateInit. sourceLen is the byte 00626 length of the source buffer. Upon entry, destLen is the total size of the 00627 destination buffer, which must be at least 0.1% larger than sourceLen plus 00628 12 bytes. Upon exit, destLen is the actual size of the compressed buffer. 00629 00630 compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 00631 memory, Z_BUF_ERROR if there was not enough room in the output buffer, 00632 Z_STREAM_ERROR if the level parameter is invalid. 00633 */ 00634 00635 extern int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen, 00636 const Bytef *source, uLong sourceLen)); 00637 /* 00638 Decompresses the source buffer into the destination buffer. sourceLen is 00639 the byte length of the source buffer. Upon entry, destLen is the total 00640 size of the destination buffer, which must be large enough to hold the 00641 entire uncompressed data. (The size of the uncompressed data must have 00642 been saved previously by the compressor and transmitted to the decompressor 00643 by some mechanism outside the scope of this compression library.) 00644 Upon exit, destLen is the actual size of the compressed buffer. 00645 This function can be used to decompress a whole file at once if the 00646 input file is mmap'ed. 00647 00648 uncompress returns Z_OK if success, Z_MEM_ERROR if there was not 00649 enough memory, Z_BUF_ERROR if there was not enough room in the output 00650 buffer, or Z_DATA_ERROR if the input data was corrupted. 00651 */ 00652 00653 00654 typedef voidp gzFile; 00655 00656 extern gzFile ZEXPORT gzopen OF((const char *path, const char *mode)); 00657 /* 00658 Opens a gzip (.gz) file for reading or writing. The mode parameter 00659 is as in fopen ("rb" or "wb") but can also include a compression level 00660 ("wb9") or a strategy: 'f' for filtered data as in "wb6f", 'h' for 00661 Huffman only compression as in "wb1h". (See the description 00662 of deflateInit2 for more information about the strategy parameter.) 00663 00664 gzopen can be used to read a file which is not in gzip format; in this 00665 case gzread will directly read from the file without decompression. 00666 00667 gzopen returns NULL if the file could not be opened or if there was 00668 insufficient memory to allocate the (de)compression state; errno 00669 can be checked to distinguish the two cases (if errno is zero, the 00670 zlib error is Z_MEM_ERROR). */ 00671 00672 extern gzFile ZEXPORT gzdopen OF((int fd, const char *mode)); 00673 /* 00674 gzdopen() associates a gzFile with the file descriptor fd. File 00675 descriptors are obtained from calls like open, dup, creat, pipe or 00676 fileno (in the file has been previously opened with fopen). 00677 The mode parameter is as in gzopen. 00678 The next call of gzclose on the returned gzFile will also close the 00679 file descriptor fd, just like fclose(fdopen(fd), mode) closes the file 00680 descriptor fd. If you want to keep fd open, use gzdopen(dup(fd), mode). 00681 gzdopen returns NULL if there was insufficient memory to allocate 00682 the (de)compression state. 00683 */ 00684 00685 extern int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy)); 00686 /* 00687 Dynamically update the compression level or strategy. See the description 00688 of deflateInit2 for the meaning of these parameters. 00689 gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not 00690 opened for writing. 00691 */ 00692 00693 extern int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len)); 00694 /* 00695 Reads the given number of uncompressed bytes from the compressed file. 00696 If the input file was not in gzip format, gzread copies the given number 00697 of bytes into the buffer. 00698 gzread returns the number of uncompressed bytes actually read (0 for 00699 end of file, -1 for error). */ 00700 00701 extern int ZEXPORT gzwrite OF((gzFile file, const voidp buf, unsigned len)); 00702 /* 00703 Writes the given number of uncompressed bytes into the compressed file. 00704 gzwrite returns the number of uncompressed bytes actually written 00705 (0 in case of error). 00706 */ 00707 00708 extern int ZEXPORTVA gzprintf OF((gzFile file, const char *format, ...)); 00709 /* 00710 Converts, formats, and writes the args to the compressed file under 00711 control of the format string, as in fprintf. gzprintf returns the number of 00712 uncompressed bytes actually written (0 in case of error). 00713 */ 00714 00715 extern int ZEXPORT gzputs OF((gzFile file, const char *s)); 00716 /* 00717 Writes the given null-terminated string to the compressed file, excluding 00718 the terminating null character. 00719 gzputs returns the number of characters written, or -1 in case of error. 00720 */ 00721 00722 extern char * ZEXPORT gzgets OF((gzFile file, char *buf, int len)); 00723 /* 00724 Reads bytes from the compressed file until len-1 characters are read, or 00725 a newline character is read and transferred to buf, or an end-of-file 00726 condition is encountered. The string is then terminated with a null 00727 character. 00728 gzgets returns buf, or Z_NULL in case of error. 00729 */ 00730 00731 extern int ZEXPORT gzputc OF((gzFile file, int c)); 00732 /* 00733 Writes c, converted to an unsigned char, into the compressed file. 00734 gzputc returns the value that was written, or -1 in case of error. 00735 */ 00736 00737 extern int ZEXPORT gzgetc OF((gzFile file)); 00738 /* 00739 Reads one byte from the compressed file. gzgetc returns this byte 00740 or -1 in case of end of file or error. 00741 */ 00742 00743 extern int ZEXPORT gzflush OF((gzFile file, int flush)); 00744 /* 00745 Flushes all pending output into the compressed file. The parameter 00746 flush is as in the deflate() function. The return value is the zlib 00747 error number (see function gzerror below). gzflush returns Z_OK if 00748 the flush parameter is Z_FINISH and all output could be flushed. 00749 gzflush should be called only when strictly necessary because it can 00750 degrade compression. 00751 */ 00752 00753 extern z_off_t ZEXPORT gzseek OF((gzFile file, z_off_t offset, int whence)); 00754 /* 00755 Sets the starting position for the next gzread or gzwrite on the given 00756 compressed file. The offset represents a number of bytes in the 00757 uncompressed data stream. The whence parameter is defined as in lseek(2); 00758 the value SEEK_END is not supported. 00759 If the file is opened for reading, this function is emulated but can be 00760 extremely slow. If the file is opened for writing, only forward seeks are 00761 supported; gzseek then compresses a sequence of zeroes up to the new 00762 starting position. 00763 00764 gzseek returns the resulting offset location as measured in bytes from 00765 the beginning of the uncompressed stream, or -1 in case of error, in 00766 particular if the file is opened for writing and the new starting position 00767 would be before the current position. 00768 */ 00769 00770 extern int ZEXPORT gzrewind OF((gzFile file)); 00771 /* 00772 Rewinds the given file. This function is supported only for reading. 00773 00774 gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET) 00775 */ 00776 00777 extern z_off_t ZEXPORT gztell OF((gzFile file)); 00778 /* 00779 Returns the starting position for the next gzread or gzwrite on the 00780 given compressed file. This position represents a number of bytes in the 00781 uncompressed data stream. 00782 00783 gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR) 00784 */ 00785 00786 extern int ZEXPORT gzeof OF((gzFile file)); 00787 /* 00788 Returns 1 when EOF has previously been detected reading the given 00789 input stream, otherwise zero. 00790 */ 00791 00792 extern int ZEXPORT gzclose OF((gzFile file)); 00793 /* 00794 Flushes all pending output if necessary, closes the compressed file 00795 and deallocates all the (de)compression state. The return value is the zlib 00796 error number (see function gzerror below). 00797 */ 00798 00799 extern const char * ZEXPORT gzerror OF((gzFile file, int *errnum)); 00800 /* 00801 Returns the error message for the last error which occurred on the 00802 given compressed file. errnum is set to zlib error number. If an 00803 error occurred in the file system and not in the compression library, 00804 errnum is set to Z_ERRNO and the application may consult errno 00805 to get the exact error code. 00806 */ 00807 00808 /* checksum functions */ 00809 00810 /* 00811 These functions are not related to compression but are exported 00812 anyway because they might be useful in applications using the 00813 compression library. 00814 */ 00815 00816 extern uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len)); 00817 00818 /* 00819 Update a running Adler-32 checksum with the bytes buf[0..len-1] and 00820 return the updated checksum. If buf is NULL, this function returns 00821 the required initial value for the checksum. 00822 An Adler-32 checksum is almost as reliable as a CRC32 but can be computed 00823 much faster. Usage example: 00824 00825 uLong adler = adler32(0L, Z_NULL, 0); 00826 00827 while (read_buffer(buffer, length) != EOF) { 00828 adler = adler32(adler, buffer, length); 00829 } 00830 if (adler != original_adler) error(); 00831 */ 00832 00833 extern uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len)); 00834 /* 00835 Update a running crc with the bytes buf[0..len-1] and return the updated 00836 crc. If buf is NULL, this function returns the required initial value 00837 for the crc. Pre- and post-conditioning (one's complement) is performed 00838 within this function so it shouldn't be done by the application. 00839 Usage example: 00840 00841 uLong crc = crc32(0L, Z_NULL, 0); 00842 00843 while (read_buffer(buffer, length) != EOF) { 00844 crc = crc32(crc, buffer, length); 00845 } 00846 if (crc != original_crc) error(); 00847 */ 00848 00849 00850 /* various hacks, don't look :) */ 00851 00852 /* deflateInit and inflateInit are macros to allow checking the zlib version 00853 * and the compiler's view of z_stream: 00854 */ 00855 extern int ZEXPORT deflateInit_ OF((z_streamp strm, int level, 00856 const char *version, int stream_size)); 00857 extern int ZEXPORT inflateInit_ OF((z_streamp strm, 00858 const char *version, int stream_size)); 00859 extern int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method, 00860 int windowBits, int memLevel, 00861 int strategy, const char *version, 00862 int stream_size)); 00863 extern int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits, 00864 const char *version, int stream_size)); 00865 #define deflateInit(strm, level) \ 00866 deflateInit_((strm), (level), ZLIB_VERSION, sizeof(z_stream)) 00867 #define inflateInit(strm) \ 00868 inflateInit_((strm), ZLIB_VERSION, sizeof(z_stream)) 00869 #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \ 00870 deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\ 00871 (strategy), ZLIB_VERSION, sizeof(z_stream)) 00872 #define inflateInit2(strm, windowBits) \ 00873 inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream)) 00874 00875 00876 #if !defined(_Z_UTIL_H) && !defined(NO_DUMMY_DECL) 00877 struct internal_state {int dummy;}; /* hack for buggy compilers */ 00878 #endif 00879 00880 extern const char * ZEXPORT zError OF((int err)); 00881 extern int ZEXPORT inflateSyncPoint OF((z_streamp z)); 00882 extern const uLongf * ZEXPORT get_crc_table OF((void)); 00883 00884 #ifdef __cplusplus 00885 } 00886 #endif 00887 00888 #endif /* _ZLIB_H */