1 /* $OpenBSD: zlib.h,v 1.6 2002/03/12 00:26:30 millert Exp $ */ 2 /* zlib.h -- interface of the 'zlib' general purpose compression library 3 version 1.1.4, March 11th, 2002 4 5 Copyright (C) 1995-2002 Jean-loup Gailly and Mark Adler 6 7 This software is provided 'as-is', without any express or implied 8 warranty. In no event will the authors be held liable for any damages 9 arising from the use of this software. 10 11 Permission is granted to anyone to use this software for any purpose, 12 including commercial applications, and to alter it and redistribute it 13 freely, subject to the following restrictions: 14 15 1. The origin of this software must not be misrepresented; you must not 16 claim that you wrote the original software. If you use this software 17 in a product, an acknowledgment in the product documentation would be 18 appreciated but is not required. 19 2. Altered source versions must be plainly marked as such, and must not be 20 misrepresented as being the original software. 21 3. This notice may not be removed or altered from any source distribution. 22 23 Jean-loup Gailly Mark Adler 24 jloup@gzip.org madler@alumni.caltech.edu 25 26 27 The data format used by the zlib library is described by RFCs (Request for 28 Comments) 1950 to 1952 in the files ftp://ds.internic.net/rfc/rfc1950.txt 29 (zlib format), rfc1951.txt (deflate format) and rfc1952.txt (gzip format). 30 */ 31 32 #ifndef _ZLIB_H 33 #define _ZLIB_H 34 35 #include "zconf.h" 36 37 #ifdef __cplusplus 38 extern "C" { 39 #endif 40 41 #define ZLIB_VERSION "1.1.4" 42 43 /* 44 The 'zlib' compression library provides in-memory compression and 45 decompression functions, including integrity checks of the uncompressed 46 data. This version of the library supports only one compression method 47 (deflation) but other algorithms will be added later and will have the same 48 stream interface. 49 50 Compression can be done in a single step if the buffers are large 51 enough (for example if an input file is mmap'ed), or can be done by 52 repeated calls of the compression function. In the latter case, the 53 application must provide more input and/or consume the output 54 (providing more output space) before each call. 55 56 The library also supports reading and writing files in gzip (.gz) format 57 with an interface similar to that of stdio. 58 59 The library does not install any signal handler. The decoder checks 60 the consistency of the compressed data, so the library should never 61 crash even in case of corrupted input. 62 */ 63 64 typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size)); 65 typedef void (*free_func) OF((voidpf opaque, voidpf address)); 66 67 struct internal_state; 68 69 typedef struct z_stream_s { 70 Bytef *next_in; /* next input byte */ 71 int avail_in; /* number of bytes available at next_in */ 72 uLong total_in; /* total nb of input bytes read so far */ 73 74 Bytef *next_out; /* next output byte should be put there */ 75 int avail_out; /* remaining free space at next_out */ 76 uLong total_out; /* total nb of bytes output so far */ 77 78 char *msg; /* last error message, NULL if no error */ 79 struct internal_state FAR *state; /* not visible by applications */ 80 81 alloc_func zalloc; /* used to allocate the internal state */ 82 free_func zfree; /* used to free the internal state */ 83 voidpf opaque; /* private data object passed to zalloc and zfree */ 84 85 int data_type; /* best guess about the data type: ascii or binary */ 86 uLong adler; /* adler32 value of the uncompressed data */ 87 uLong reserved; /* reserved for future use */ 88 } z_stream; 89 90 typedef z_stream FAR *z_streamp; 91 92 /* 93 The application must update next_in and avail_in when avail_in has 94 dropped to zero. It must update next_out and avail_out when avail_out 95 has dropped to zero. The application must initialize zalloc, zfree and 96 opaque before calling the init function. All other fields are set by the 97 compression library and must not be updated by the application. 98 99 The opaque value provided by the application will be passed as the first 100 parameter for calls of zalloc and zfree. This can be useful for custom 101 memory management. The compression library attaches no meaning to the 102 opaque value. 103 104 zalloc must return Z_NULL if there is not enough memory for the object. 105 If zlib is used in a multi-threaded application, zalloc and zfree must be 106 thread safe. 107 108 On 16-bit systems, the functions zalloc and zfree must be able to allocate 109 exactly 65536 bytes, but will not be required to allocate more than this 110 if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, 111 pointers returned by zalloc for objects of exactly 65536 bytes *must* 112 have their offset normalized to zero. The default allocation function 113 provided by this library ensures this (see zutil.c). To reduce memory 114 requirements and avoid any allocation of 64K objects, at the expense of 115 compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h). 116 117 The fields total_in and total_out can be used for statistics or 118 progress reports. After compression, total_in holds the total size of 119 the uncompressed data and may be saved for use in the decompressor 120 (particularly if the decompressor wants to decompress everything in 121 a single step). 122 */ 123 124 /* constants */ 125 126 #define Z_NO_FLUSH 0 127 #define Z_PARTIAL_FLUSH 1 /* will be removed, use Z_SYNC_FLUSH instead */ 128 #define Z_SYNC_FLUSH 2 129 #define Z_FULL_FLUSH 3 130 #define Z_FINISH 4 131 /* Allowed flush values; see deflate() below for details */ 132 133 #define Z_OK 0 134 #define Z_STREAM_END 1 135 #define Z_NEED_DICT 2 136 #define Z_ERRNO (-1) 137 #define Z_STREAM_ERROR (-2) 138 #define Z_DATA_ERROR (-3) 139 #define Z_MEM_ERROR (-4) 140 #define Z_BUF_ERROR (-5) 141 #define Z_VERSION_ERROR (-6) 142 /* Return codes for the compression/decompression functions. Negative 143 * values are errors, positive values are used for special but normal events. 144 */ 145 146 #define Z_NO_COMPRESSION 0 147 #define Z_BEST_SPEED 1 148 #define Z_BEST_COMPRESSION 9 149 #define Z_DEFAULT_COMPRESSION (-1) 150 /* compression levels */ 151 152 #define Z_FILTERED 1 153 #define Z_HUFFMAN_ONLY 2 154 #define Z_DEFAULT_STRATEGY 0 155 /* compression strategy; see deflateInit2() below for details */ 156 157 #define Z_BINARY 0 158 #define Z_ASCII 1 159 #define Z_UNKNOWN 2 160 /* Possible values of the data_type field */ 161 162 #define Z_DEFLATED 8 163 /* The deflate compression method (the only one supported in this version) */ 164 165 #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */ 166 167 #define zlib_version zlibVersion() 168 /* for compatibility with versions < 1.0.2 */ 169 170 /* basic functions */ 171 172 ZEXTERN const char * ZEXPORT zlibVersion OF((void)); 173 /* The application can compare zlibVersion and ZLIB_VERSION for consistency. 174 If the first character differs, the library code actually used is 175 not compatible with the zlib.h header file used by the application. 176 This check is automatically made by deflateInit and inflateInit. 177 */ 178 179 /* 180 ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level)); 181 182 Initializes the internal stream state for compression. The fields 183 zalloc, zfree and opaque must be initialized before by the caller. 184 If zalloc and zfree are set to Z_NULL, deflateInit updates them to 185 use default allocation functions. 186 187 The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9: 188 1 gives best speed, 9 gives best compression, 0 gives no compression at 189 all (the input data is simply copied a block at a time). 190 Z_DEFAULT_COMPRESSION requests a default compromise between speed and 191 compression (currently equivalent to level 6). 192 193 deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not 194 enough memory, Z_STREAM_ERROR if level is not a valid compression level, 195 Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible 196 with the version assumed by the caller (ZLIB_VERSION). 197 msg is set to null if there is no error message. deflateInit does not 198 perform any compression: this will be done by deflate(). 199 */ 200 201 202 ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush)); 203 /* 204 deflate compresses as much data as possible, and stops when the input 205 buffer becomes empty or the output buffer becomes full. It may introduce some 206 output latency (reading input without producing any output) except when 207 forced to flush. 208 209 The detailed semantics are as follows. deflate performs one or both of the 210 following actions: 211 212 - Compress more input starting at next_in and update next_in and avail_in 213 accordingly. If not all input can be processed (because there is not 214 enough room in the output buffer), next_in and avail_in are updated and 215 processing will resume at this point for the next call of deflate(). 216 217 - Provide more output starting at next_out and update next_out and avail_out 218 accordingly. This action is forced if the parameter flush is non zero. 219 Forcing flush frequently degrades the compression ratio, so this parameter 220 should be set only when necessary (in interactive applications). 221 Some output may be provided even if flush is not set. 222 223 Before the call of deflate(), the application should ensure that at least 224 one of the actions is possible, by providing more input and/or consuming 225 more output, and updating avail_in or avail_out accordingly; avail_out 226 should never be zero before the call. The application can consume the 227 compressed output when it wants, for example when the output buffer is full 228 (avail_out == 0), or after each call of deflate(). If deflate returns Z_OK 229 and with zero avail_out, it must be called again after making room in the 230 output buffer because there might be more output pending. 231 232 If the parameter flush is set to Z_SYNC_FLUSH, all pending output is 233 flushed to the output buffer and the output is aligned on a byte boundary, so 234 that the decompressor can get all input data available so far. (In particular 235 avail_in is zero after the call if enough output space has been provided 236 before the call.) Flushing may degrade compression for some compression 237 algorithms and so it should be used only when necessary. 238 239 If flush is set to Z_FULL_FLUSH, all output is flushed as with 240 Z_SYNC_FLUSH, and the compression state is reset so that decompression can 241 restart from this point if previous compressed data has been damaged or if 242 random access is desired. Using Z_FULL_FLUSH too often can seriously degrade 243 the compression. 244 245 If deflate returns with avail_out == 0, this function must be called again 246 with the same value of the flush parameter and more output space (updated 247 avail_out), until the flush is complete (deflate returns with non-zero 248 avail_out). 249 250 If the parameter flush is set to Z_FINISH, pending input is processed, 251 pending output is flushed and deflate returns with Z_STREAM_END if there 252 was enough output space; if deflate returns with Z_OK, this function must be 253 called again with Z_FINISH and more output space (updated avail_out) but no 254 more input data, until it returns with Z_STREAM_END or an error. After 255 deflate has returned Z_STREAM_END, the only possible operations on the 256 stream are deflateReset or deflateEnd. 257 258 Z_FINISH can be used immediately after deflateInit if all the compression 259 is to be done in a single step. In this case, avail_out must be at least 260 0.1% larger than avail_in plus 12 bytes. If deflate does not return 261 Z_STREAM_END, then it must be called again as described above. 262 263 deflate() sets strm->adler to the adler32 checksum of all input read 264 so far (that is, total_in bytes). 265 266 deflate() may update data_type if it can make a good guess about 267 the input data type (Z_ASCII or Z_BINARY). In doubt, the data is considered 268 binary. This field is only for information purposes and does not affect 269 the compression algorithm in any manner. 270 271 deflate() returns Z_OK if some progress has been made (more input 272 processed or more output produced), Z_STREAM_END if all input has been 273 consumed and all output has been produced (only when flush is set to 274 Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example 275 if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible 276 (for example avail_in or avail_out was zero). 277 */ 278 279 280 ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm)); 281 /* 282 All dynamically allocated data structures for this stream are freed. 283 This function discards any unprocessed input and does not flush any 284 pending output. 285 286 deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the 287 stream state was inconsistent, Z_DATA_ERROR if the stream was freed 288 prematurely (some input or output was discarded). In the error case, 289 msg may be set but then points to a static string (which must not be 290 deallocated). 291 */ 292 293 294 /* 295 ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm)); 296 297 Initializes the internal stream state for decompression. The fields 298 next_in, avail_in, zalloc, zfree and opaque must be initialized before by 299 the caller. If next_in is not Z_NULL and avail_in is large enough (the exact 300 value depends on the compression method), inflateInit determines the 301 compression method from the zlib header and allocates all data structures 302 accordingly; otherwise the allocation will be deferred to the first call of 303 inflate. If zalloc and zfree are set to Z_NULL, inflateInit updates them to 304 use default allocation functions. 305 306 inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough 307 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the 308 version assumed by the caller. msg is set to null if there is no error 309 message. inflateInit does not perform any decompression apart from reading 310 the zlib header if present: this will be done by inflate(). (So next_in and 311 avail_in may be modified, but next_out and avail_out are unchanged.) 312 */ 313 314 315 ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush)); 316 /* 317 inflate decompresses as much data as possible, and stops when the input 318 buffer becomes empty or the output buffer becomes full. It may some 319 introduce some output latency (reading input without producing any output) 320 except when forced to flush. 321 322 The detailed semantics are as follows. inflate performs one or both of the 323 following actions: 324 325 - Decompress more input starting at next_in and update next_in and avail_in 326 accordingly. If not all input can be processed (because there is not 327 enough room in the output buffer), next_in is updated and processing 328 will resume at this point for the next call of inflate(). 329 330 - Provide more output starting at next_out and update next_out and avail_out 331 accordingly. inflate() provides as much output as possible, until there 332 is no more input data or no more space in the output buffer (see below 333 about the flush parameter). 334 335 Before the call of inflate(), the application should ensure that at least 336 one of the actions is possible, by providing more input and/or consuming 337 more output, and updating the next_* and avail_* values accordingly. 338 The application can consume the uncompressed output when it wants, for 339 example when the output buffer is full (avail_out == 0), or after each 340 call of inflate(). If inflate returns Z_OK and with zero avail_out, it 341 must be called again after making room in the output buffer because there 342 might be more output pending. 343 344 If the parameter flush is set to Z_SYNC_FLUSH, inflate flushes as much 345 output as possible to the output buffer. The flushing behavior of inflate is 346 not specified for values of the flush parameter other than Z_SYNC_FLUSH 347 and Z_FINISH, but the current implementation actually flushes as much output 348 as possible anyway. 349 350 inflate() should normally be called until it returns Z_STREAM_END or an 351 error. However if all decompression is to be performed in a single step 352 (a single call of inflate), the parameter flush should be set to 353 Z_FINISH. In this case all pending input is processed and all pending 354 output is flushed; avail_out must be large enough to hold all the 355 uncompressed data. (The size of the uncompressed data may have been saved 356 by the compressor for this purpose.) The next operation on this stream must 357 be inflateEnd to deallocate the decompression state. The use of Z_FINISH 358 is never required, but can be used to inform inflate that a faster routine 359 may be used for the single inflate() call. 360 361 If a preset dictionary is needed at this point (see inflateSetDictionary 362 below), inflate sets strm-adler to the adler32 checksum of the 363 dictionary chosen by the compressor and returns Z_NEED_DICT; otherwise 364 it sets strm->adler to the adler32 checksum of all output produced 365 so far (that is, total_out bytes) and returns Z_OK, Z_STREAM_END or 366 an error code as described below. At the end of the stream, inflate() 367 checks that its computed adler32 checksum is equal to that saved by the 368 compressor and returns Z_STREAM_END only if the checksum is correct. 369 370 inflate() returns Z_OK if some progress has been made (more input processed 371 or more output produced), Z_STREAM_END if the end of the compressed data has 372 been reached and all uncompressed output has been produced, Z_NEED_DICT if a 373 preset dictionary is needed at this point, Z_DATA_ERROR if the input data was 374 corrupted (input stream not conforming to the zlib format or incorrect 375 adler32 checksum), Z_STREAM_ERROR if the stream structure was inconsistent 376 (for example if next_in or next_out was NULL), Z_MEM_ERROR if there was not 377 enough memory, Z_BUF_ERROR if no progress is possible or if there was not 378 enough room in the output buffer when Z_FINISH is used. In the Z_DATA_ERROR 379 case, the application may then call inflateSync to look for a good 380 compression block. 381 */ 382 383 384 ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm)); 385 /* 386 All dynamically allocated data structures for this stream are freed. 387 This function discards any unprocessed input and does not flush any 388 pending output. 389 390 inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state 391 was inconsistent. In the error case, msg may be set but then points to a 392 static string (which must not be deallocated). 393 */ 394 395 /* Advanced functions */ 396 397 /* 398 The following functions are needed only in some special applications. 399 */ 400 401 /* 402 ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm, 403 int level, 404 int method, 405 int windowBits, 406 int memLevel, 407 int strategy)); 408 409 This is another version of deflateInit with more compression options. The 410 fields next_in, zalloc, zfree and opaque must be initialized before by 411 the caller. 412 413 The method parameter is the compression method. It must be Z_DEFLATED in 414 this version of the library. 415 416 The windowBits parameter is the base two logarithm of the window size 417 (the size of the history buffer). It should be in the range 8..15 for this 418 version of the library. Larger values of this parameter result in better 419 compression at the expense of memory usage. The default value is 15 if 420 deflateInit is used instead. 421 422 The memLevel parameter specifies how much memory should be allocated 423 for the internal compression state. memLevel=1 uses minimum memory but 424 is slow and reduces compression ratio; memLevel=9 uses maximum memory 425 for optimal speed. The default value is 8. See zconf.h for total memory 426 usage as a function of windowBits and memLevel. 427 428 The strategy parameter is used to tune the compression algorithm. Use the 429 value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a 430 filter (or predictor), or Z_HUFFMAN_ONLY to force Huffman encoding only (no 431 string match). Filtered data consists mostly of small values with a 432 somewhat random distribution. In this case, the compression algorithm is 433 tuned to compress them better. The effect of Z_FILTERED is to force more 434 Huffman coding and less string matching; it is somewhat intermediate 435 between Z_DEFAULT and Z_HUFFMAN_ONLY. The strategy parameter only affects 436 the compression ratio but not the correctness of the compressed output even 437 if it is not set appropriately. 438 439 deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 440 memory, Z_STREAM_ERROR if a parameter is invalid (such as an invalid 441 method). msg is set to null if there is no error message. deflateInit2 does 442 not perform any compression: this will be done by deflate(). 443 */ 444 445 ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm, 446 const Bytef *dictionary, 447 uInt dictLength)); 448 /* 449 Initializes the compression dictionary from the given byte sequence 450 without producing any compressed output. This function must be called 451 immediately after deflateInit, deflateInit2 or deflateReset, before any 452 call of deflate. The compressor and decompressor must use exactly the same 453 dictionary (see inflateSetDictionary). 454 455 The dictionary should consist of strings (byte sequences) that are likely 456 to be encountered later in the data to be compressed, with the most commonly 457 used strings preferably put towards the end of the dictionary. Using a 458 dictionary is most useful when the data to be compressed is short and can be 459 predicted with good accuracy; the data can then be compressed better than 460 with the default empty dictionary. 461 462 Depending on the size of the compression data structures selected by 463 deflateInit or deflateInit2, a part of the dictionary may in effect be 464 discarded, for example if the dictionary is larger than the window size in 465 deflate or deflate2. Thus the strings most likely to be useful should be 466 put at the end of the dictionary, not at the front. 467 468 Upon return of this function, strm->adler is set to the Adler32 value 469 of the dictionary; the decompressor may later use this value to determine 470 which dictionary has been used by the compressor. (The Adler32 value 471 applies to the whole dictionary even if only a subset of the dictionary is 472 actually used by the compressor.) 473 474 deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a 475 parameter is invalid (such as NULL dictionary) or the stream state is 476 inconsistent (for example if deflate has already been called for this stream 477 or if the compression method is bsort). deflateSetDictionary does not 478 perform any compression: this will be done by deflate(). 479 */ 480 481 ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest, 482 z_streamp source)); 483 /* 484 Sets the destination stream as a complete copy of the source stream. 485 486 This function can be useful when several compression strategies will be 487 tried, for example when there are several ways of pre-processing the input 488 data with a filter. The streams that will be discarded should then be freed 489 by calling deflateEnd. Note that deflateCopy duplicates the internal 490 compression state which can be quite large, so this strategy is slow and 491 can consume lots of memory. 492 493 deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not 494 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent 495 (such as zalloc being NULL). msg is left unchanged in both source and 496 destination. 497 */ 498 499 ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm)); 500 /* 501 This function is equivalent to deflateEnd followed by deflateInit, 502 but does not free and reallocate all the internal compression state. 503 The stream will keep the same compression level and any other attributes 504 that may have been set by deflateInit2. 505 506 deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source 507 stream state was inconsistent (such as zalloc or state being NULL). 508 */ 509 510 ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm, 511 int level, 512 int strategy)); 513 /* 514 Dynamically update the compression level and compression strategy. The 515 interpretation of level and strategy is as in deflateInit2. This can be 516 used to switch between compression and straight copy of the input data, or 517 to switch to a different kind of input data requiring a different 518 strategy. If the compression level is changed, the input available so far 519 is compressed with the old level (and may be flushed); the new level will 520 take effect only at the next call of deflate(). 521 522 Before the call of deflateParams, the stream state must be set as for 523 a call of deflate(), since the currently available input may have to 524 be compressed and flushed. In particular, strm->avail_out must be non-zero. 525 526 deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source 527 stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR 528 if strm->avail_out was zero. 529 */ 530 531 /* 532 ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm, 533 int windowBits)); 534 535 This is another version of inflateInit with an extra parameter. The 536 fields next_in, avail_in, zalloc, zfree and opaque must be initialized 537 before by the caller. 538 539 The windowBits parameter is the base two logarithm of the maximum window 540 size (the size of the history buffer). It should be in the range 8..15 for 541 this version of the library. The default value is 15 if inflateInit is used 542 instead. If a compressed stream with a larger window size is given as 543 input, inflate() will return with the error code Z_DATA_ERROR instead of 544 trying to allocate a larger window. 545 546 inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 547 memory, Z_STREAM_ERROR if a parameter is invalid (such as a negative 548 memLevel). msg is set to null if there is no error message. inflateInit2 549 does not perform any decompression apart from reading the zlib header if 550 present: this will be done by inflate(). (So next_in and avail_in may be 551 modified, but next_out and avail_out are unchanged.) 552 */ 553 554 ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm, 555 const Bytef *dictionary, 556 uInt dictLength)); 557 /* 558 Initializes the decompression dictionary from the given uncompressed byte 559 sequence. This function must be called immediately after a call of inflate 560 if this call returned Z_NEED_DICT. The dictionary chosen by the compressor 561 can be determined from the Adler32 value returned by this call of 562 inflate. The compressor and decompressor must use exactly the same 563 dictionary (see deflateSetDictionary). 564 565 inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a 566 parameter is invalid (such as NULL dictionary) or the stream state is 567 inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the 568 expected one (incorrect Adler32 value). inflateSetDictionary does not 569 perform any decompression: this will be done by subsequent calls of 570 inflate(). 571 */ 572 573 ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm)); 574 /* 575 Skips invalid compressed data until a full flush point (see above the 576 description of deflate with Z_FULL_FLUSH) can be found, or until all 577 available input is skipped. No output is provided. 578 579 inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR 580 if no more input was provided, Z_DATA_ERROR if no flush point has been found, 581 or Z_STREAM_ERROR if the stream structure was inconsistent. In the success 582 case, the application may save the current current value of total_in which 583 indicates where valid compressed data was found. In the error case, the 584 application may repeatedly call inflateSync, providing more input each time, 585 until success or end of the input data. 586 */ 587 588 ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm)); 589 /* 590 This function is equivalent to inflateEnd followed by inflateInit, 591 but does not free and reallocate all the internal decompression state. 592 The stream will keep attributes that may have been set by inflateInit2. 593 594 inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source 595 stream state was inconsistent (such as zalloc or state being NULL). 596 */ 597 598 599 /* utility functions */ 600 601 /* 602 The following utility functions are implemented on top of the 603 basic stream-oriented functions. To simplify the interface, some 604 default options are assumed (compression level and memory usage, 605 standard memory allocation functions). The source code of these 606 utility functions can easily be modified if you need special options. 607 */ 608 609 ZEXTERN int ZEXPORT compress OF((Bytef *dest, uLongf *destLen, 610 const Bytef *source, uLong sourceLen)); 611 /* 612 Compresses the source buffer into the destination buffer. sourceLen is 613 the byte length of the source buffer. Upon entry, destLen is the total 614 size of the destination buffer, which must be at least 0.1% larger than 615 sourceLen plus 12 bytes. Upon exit, destLen is the actual size of the 616 compressed buffer. 617 This function can be used to compress a whole file at once if the 618 input file is mmap'ed. 619 compress returns Z_OK if success, Z_MEM_ERROR if there was not 620 enough memory, Z_BUF_ERROR if there was not enough room in the output 621 buffer. 622 */ 623 624 ZEXTERN int ZEXPORT compress2 OF((Bytef *dest, uLongf *destLen, 625 const Bytef *source, uLong sourceLen, 626 int level)); 627 /* 628 Compresses the source buffer into the destination buffer. The level 629 parameter has the same meaning as in deflateInit. sourceLen is the byte 630 length of the source buffer. Upon entry, destLen is the total size of the 631 destination buffer, which must be at least 0.1% larger than sourceLen plus 632 12 bytes. Upon exit, destLen is the actual size of the compressed buffer. 633 634 compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 635 memory, Z_BUF_ERROR if there was not enough room in the output buffer, 636 Z_STREAM_ERROR if the level parameter is invalid. 637 */ 638 639 ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen, 640 const Bytef *source, uLong sourceLen)); 641 /* 642 Decompresses the source buffer into the destination buffer. sourceLen is 643 the byte length of the source buffer. Upon entry, destLen is the total 644 size of the destination buffer, which must be large enough to hold the 645 entire uncompressed data. (The size of the uncompressed data must have 646 been saved previously by the compressor and transmitted to the decompressor 647 by some mechanism outside the scope of this compression library.) 648 Upon exit, destLen is the actual size of the compressed buffer. 649 This function can be used to decompress a whole file at once if the 650 input file is mmap'ed. 651 652 uncompress returns Z_OK if success, Z_MEM_ERROR if there was not 653 enough memory, Z_BUF_ERROR if there was not enough room in the output 654 buffer, or Z_DATA_ERROR if the input data was corrupted. 655 */ 656 657 658 typedef voidp gzFile; 659 660 ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode)); 661 /* 662 Opens a gzip (.gz) file for reading or writing. The mode parameter 663 is as in fopen ("rb" or "wb") but can also include a compression level 664 ("wb9") or a strategy: 'f' for filtered data as in "wb6f", 'h' for 665 Huffman only compression as in "wb1h". (See the description 666 of deflateInit2 for more information about the strategy parameter.) 667 668 gzopen can be used to read a file which is not in gzip format; in this 669 case gzread will directly read from the file without decompression. 670 671 gzopen returns NULL if the file could not be opened or if there was 672 insufficient memory to allocate the (de)compression state; errno 673 can be checked to distinguish the two cases (if errno is zero, the 674 zlib error is Z_MEM_ERROR). */ 675 676 ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode)); 677 /* 678 gzdopen() associates a gzFile with the file descriptor fd. File 679 descriptors are obtained from calls like open, dup, creat, pipe or 680 fileno (in the file has been previously opened with fopen). 681 The mode parameter is as in gzopen. 682 The next call of gzclose on the returned gzFile will also close the 683 file descriptor fd, just like fclose(fdopen(fd), mode) closes the file 684 descriptor fd. If you want to keep fd open, use gzdopen(dup(fd), mode). 685 gzdopen returns NULL if there was insufficient memory to allocate 686 the (de)compression state. 687 */ 688 689 ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy)); 690 /* 691 Dynamically update the compression level or strategy. See the description 692 of deflateInit2 for the meaning of these parameters. 693 gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not 694 opened for writing. 695 */ 696 697 ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len)); 698 /* 699 Reads the given number of uncompressed bytes from the compressed file. 700 If the input file was not in gzip format, gzread copies the given number 701 of bytes into the buffer. 702 gzread returns the number of uncompressed bytes actually read (0 for 703 end of file, -1 for error). */ 704 705 ZEXTERN int ZEXPORT gzwrite OF((gzFile file, 706 const voidp buf, unsigned len)); 707 /* 708 Writes the given number of uncompressed bytes into the compressed file. 709 gzwrite returns the number of uncompressed bytes actually written 710 (0 in case of error). 711 */ 712 713 ZEXTERN int ZEXPORTVA gzprintf OF((gzFile file, const char *format, ...)); 714 /* 715 Converts, formats, and writes the args to the compressed file under 716 control of the format string, as in fprintf. gzprintf returns the number of 717 uncompressed bytes actually written (0 in case of error). 718 */ 719 720 ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s)); 721 /* 722 Writes the given null-terminated string to the compressed file, excluding 723 the terminating null character. 724 gzputs returns the number of characters written, or -1 in case of error. 725 */ 726 727 ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len)); 728 /* 729 Reads bytes from the compressed file until len-1 characters are read, or 730 a newline character is read and transferred to buf, or an end-of-file 731 condition is encountered. The string is then terminated with a null 732 character. 733 gzgets returns buf, or Z_NULL in case of error. 734 */ 735 736 ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c)); 737 /* 738 Writes c, converted to an unsigned char, into the compressed file. 739 gzputc returns the value that was written, or -1 in case of error. 740 */ 741 742 ZEXTERN int ZEXPORT gzgetc OF((gzFile file)); 743 /* 744 Reads one byte from the compressed file. gzgetc returns this byte 745 or -1 in case of end of file or error. 746 */ 747 748 ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush)); 749 /* 750 Flushes all pending output into the compressed file. The parameter 751 flush is as in the deflate() function. The return value is the zlib 752 error number (see function gzerror below). gzflush returns Z_OK if 753 the flush parameter is Z_FINISH and all output could be flushed. 754 gzflush should be called only when strictly necessary because it can 755 degrade compression. 756 */ 757 758 ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file, 759 z_off_t offset, int whence)); 760 /* 761 Sets the starting position for the next gzread or gzwrite on the 762 given compressed file. The offset represents a number of bytes in the 763 uncompressed data stream. The whence parameter is defined as in lseek(2); 764 the value SEEK_END is not supported. 765 If the file is opened for reading, this function is emulated but can be 766 extremely slow. If the file is opened for writing, only forward seeks are 767 supported; gzseek then compresses a sequence of zeroes up to the new 768 starting position. 769 770 gzseek returns the resulting offset location as measured in bytes from 771 the beginning of the uncompressed stream, or -1 in case of error, in 772 particular if the file is opened for writing and the new starting position 773 would be before the current position. 774 */ 775 776 ZEXTERN int ZEXPORT gzrewind OF((gzFile file)); 777 /* 778 Rewinds the given file. This function is supported only for reading. 779 780 gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET) 781 */ 782 783 ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file)); 784 /* 785 Returns the starting position for the next gzread or gzwrite on the 786 given compressed file. This position represents a number of bytes in the 787 uncompressed data stream. 788 789 gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR) 790 */ 791 792 ZEXTERN int ZEXPORT gzeof OF((gzFile file)); 793 /* 794 Returns 1 when EOF has previously been detected reading the given 795 input stream, otherwise zero. 796 */ 797 798 ZEXTERN int ZEXPORT gzclose OF((gzFile file)); 799 /* 800 Flushes all pending output if necessary, closes the compressed file 801 and deallocates all the (de)compression state. The return value is the zlib 802 error number (see function gzerror below). 803 */ 804 805 ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum)); 806 /* 807 Returns the error message for the last error which occurred on the 808 given compressed file. errnum is set to zlib error number. If an 809 error occurred in the file system and not in the compression library, 810 errnum is set to Z_ERRNO and the application may consult errno 811 to get the exact error code. 812 */ 813 814 /* checksum functions */ 815 816 /* 817 These functions are not related to compression but are exported 818 anyway because they might be useful in applications using the 819 compression library. 820 */ 821 822 ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len)); 823 824 /* 825 Update a running Adler-32 checksum with the bytes buf[0..len-1] and 826 return the updated checksum. If buf is NULL, this function returns 827 the required initial value for the checksum. 828 An Adler-32 checksum is almost as reliable as a CRC32 but can be computed 829 much faster. Usage example: 830 831 uLong adler = adler32(0L, Z_NULL, 0); 832 833 while (read_buffer(buffer, length) != EOF) { 834 adler = adler32(adler, buffer, length); 835 } 836 if (adler != original_adler) error(); 837 */ 838 839 ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len)); 840 /* 841 Update a running crc with the bytes buf[0..len-1] and return the updated 842 crc. If buf is NULL, this function returns the required initial value 843 for the crc. Pre- and post-conditioning (one's complement) is performed 844 within this function so it shouldn't be done by the application. 845 Usage example: 846 847 uLong crc = crc32(0L, Z_NULL, 0); 848 849 while (read_buffer(buffer, length) != EOF) { 850 crc = crc32(crc, buffer, length); 851 } 852 if (crc != original_crc) error(); 853 */ 854 855 856 /* various hacks, don't look :) */ 857 858 /* deflateInit and inflateInit are macros to allow checking the zlib version 859 * and the compiler's view of z_stream: 860 */ 861 ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level, 862 const char *version, int stream_size)); 863 ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm, 864 const char *version, int stream_size)); 865 ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method, 866 int windowBits, int memLevel, 867 int strategy, const char *version, 868 int stream_size)); 869 ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits, 870 const char *version, int stream_size)); 871 #define deflateInit(strm, level) \ 872 deflateInit_((strm), (level), ZLIB_VERSION, sizeof(z_stream)) 873 #define inflateInit(strm) \ 874 inflateInit_((strm), ZLIB_VERSION, sizeof(z_stream)) 875 #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \ 876 deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\ 877 (strategy), ZLIB_VERSION, sizeof(z_stream)) 878 #define inflateInit2(strm, windowBits) \ 879 inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream)) 880 881 882 #if !defined(_Z_UTIL_H) && !defined(NO_DUMMY_DECL) 883 struct internal_state {int dummy;}; /* hack for buggy compilers */ 884 #endif 885 886 ZEXTERN const char * ZEXPORT zError OF((int err)); 887 ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp z)); 888 ZEXTERN const uLongf * ZEXPORT get_crc_table OF((void)); 889 890 #ifdef __cplusplus 891 } 892 #endif 893 894 #endif /* _ZLIB_H */ 895