1 /* zlib.h -- interface of the 'zlib' general purpose compression library 2 version 1.0.4, Jul 24th, 1996. 3 4 Copyright (C) 1995-1996 Jean-loup Gailly and Mark Adler 5 6 This software is provided 'as-is', without any express or implied 7 warranty. In no event will the authors be held liable for any damages 8 arising from the use of this software. 9 10 Permission is granted to anyone to use this software for any purpose, 11 including commercial applications, and to alter it and redistribute it 12 freely, subject to the following restrictions: 13 14 1. The origin of this software must not be misrepresented; you must not 15 claim that you wrote the original software. If you use this software 16 in a product, an acknowledgment in the product documentation would be 17 appreciated but is not required. 18 2. Altered source versions must be plainly marked as such, and must not be 19 misrepresented as being the original software. 20 3. This notice may not be removed or altered from any source distribution. 21 22 Jean-loup Gailly Mark Adler 23 gzip@prep.ai.mit.edu madler@alumni.caltech.edu 24 25 26 The data format used by the zlib library is described by RFCs (Request for 27 Comments) 1950 to 1952 in the files ftp://ds.internic.net/rfc/rfc1950.txt 28 (zlib format), rfc1951.txt (deflate format) and rfc1952.txt (gzip format). 29 */ 30 31 #ifndef _ZLIB_H 32 #define _ZLIB_H 33 34 #ifdef __cplusplus 35 extern "C" { 36 #endif 37 38 #include "zconf.h" 39 40 #define ZLIB_VERSION "1.0.4" 41 42 /* 43 The 'zlib' compression library provides in-memory compression and 44 decompression functions, including integrity checks of the uncompressed 45 data. This version of the library supports only one compression method 46 (deflation) but other algorithms may be added later and will have the same 47 stream interface. 48 49 For compression the application must provide the output buffer and 50 may optionally provide the input buffer for optimization. For decompression, 51 the application must provide the input buffer and may optionally provide 52 the output buffer for optimization. 53 54 Compression can be done in a single step if the buffers are large 55 enough (for example if an input file is mmap'ed), or can be done by 56 repeated calls of the compression function. In the latter case, the 57 application must provide more input and/or consume the output 58 (providing more output space) before each call. 59 60 The library does not install any signal handler. It is recommended to 61 add at least a handler for SIGSEGV when decompressing; the library checks 62 the consistency of the input data whenever possible but may go nuts 63 for some forms of corrupted input. 64 */ 65 66 typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size)); 67 typedef void (*free_func) OF((voidpf opaque, voidpf address)); 68 69 struct internal_state; 70 71 typedef struct z_stream_s { 72 Bytef *next_in; /* next input byte */ 73 uInt avail_in; /* number of bytes available at next_in */ 74 uLong total_in; /* total nb of input bytes read so far */ 75 76 Bytef *next_out; /* next output byte should be put there */ 77 uInt avail_out; /* remaining free space at next_out */ 78 uLong total_out; /* total nb of bytes output so far */ 79 80 char *msg; /* last error message, NULL if no error */ 81 struct internal_state FAR *state; /* not visible by applications */ 82 83 alloc_func zalloc; /* used to allocate the internal state */ 84 free_func zfree; /* used to free the internal state */ 85 voidpf opaque; /* private data object passed to zalloc and zfree */ 86 87 int data_type; /* best guess about the data type: ascii or binary */ 88 uLong adler; /* adler32 value of the uncompressed data */ 89 uLong reserved; /* reserved for future use */ 90 } z_stream; 91 92 typedef z_stream FAR *z_streamp; 93 94 /* 95 The application must update next_in and avail_in when avail_in has 96 dropped to zero. It must update next_out and avail_out when avail_out 97 has dropped to zero. The application must initialize zalloc, zfree and 98 opaque before calling the init function. All other fields are set by the 99 compression library and must not be updated by the application. 100 101 The opaque value provided by the application will be passed as the first 102 parameter for calls of zalloc and zfree. This can be useful for custom 103 memory management. The compression library attaches no meaning to the 104 opaque value. 105 106 zalloc must return Z_NULL if there is not enough memory for the object. 107 On 16-bit systems, the functions zalloc and zfree must be able to allocate 108 exactly 65536 bytes, but will not be required to allocate more than this 109 if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, 110 pointers returned by zalloc for objects of exactly 65536 bytes *must* 111 have their offset normalized to zero. The default allocation function 112 provided by this library ensures this (see zutil.c). To reduce memory 113 requirements and avoid any allocation of 64K objects, at the expense of 114 compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h). 115 116 The fields total_in and total_out can be used for statistics or 117 progress reports. After compression, total_in holds the total size of 118 the uncompressed data and may be saved for use in the decompressor 119 (particularly if the decompressor wants to decompress everything in 120 a single step). 121 */ 122 123 /* constants */ 124 125 #define Z_NO_FLUSH 0 126 #define Z_PARTIAL_FLUSH 1 127 #define Z_SYNC_FLUSH 2 128 #define Z_FULL_FLUSH 3 129 #define Z_FINISH 4 130 /* Allowed flush values; see deflate() below for details */ 131 132 #define Z_OK 0 133 #define Z_STREAM_END 1 134 #define Z_NEED_DICT 2 135 #define Z_ERRNO (-1) 136 #define Z_STREAM_ERROR (-2) 137 #define Z_DATA_ERROR (-3) 138 #define Z_MEM_ERROR (-4) 139 #define Z_BUF_ERROR (-5) 140 #define Z_VERSION_ERROR (-6) 141 /* Return codes for the compression/decompression functions. Negative 142 * values are errors, positive values are used for special but normal events. 143 */ 144 145 #define Z_NO_COMPRESSION 0 146 #define Z_BEST_SPEED 1 147 #define Z_BEST_COMPRESSION 9 148 #define Z_DEFAULT_COMPRESSION (-1) 149 /* compression levels */ 150 151 #define Z_FILTERED 1 152 #define Z_HUFFMAN_ONLY 2 153 #define Z_DEFAULT_STRATEGY 0 154 /* compression strategy; see deflateInit2() below for details */ 155 156 #define Z_BINARY 0 157 #define Z_ASCII 1 158 #define Z_UNKNOWN 2 159 /* Possible values of the data_type field */ 160 161 #define Z_DEFLATED 8 162 /* The deflate compression method (the only one supported in this version) */ 163 164 #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */ 165 166 #define zlib_version zlibVersion() 167 /* for compatibility with versions < 1.0.2 */ 168 169 /* basic functions */ 170 171 extern const char * EXPORT zlibVersion OF((void)); 172 /* The application can compare zlibVersion and ZLIB_VERSION for consistency. 173 If the first character differs, the library code actually used is 174 not compatible with the zlib.h header file used by the application. 175 This check is automatically made by deflateInit and inflateInit. 176 */ 177 178 /* 179 extern int EXPORT deflateInit OF((z_streamp strm, int level)); 180 181 Initializes the internal stream state for compression. The fields 182 zalloc, zfree and opaque must be initialized before by the caller. 183 If zalloc and zfree are set to Z_NULL, deflateInit updates them to 184 use default allocation functions. 185 186 The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9: 187 1 gives best speed, 9 gives best compression, 0 gives no compression at 188 all (the input data is simply copied a block at a time). 189 Z_DEFAULT_COMPRESSION requests a default compromise between speed and 190 compression (currently equivalent to level 6). 191 192 deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not 193 enough memory, Z_STREAM_ERROR if level is not a valid compression level, 194 Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible 195 with the version assumed by the caller (ZLIB_VERSION). 196 msg is set to null if there is no error message. deflateInit does not 197 perform any compression: this will be done by deflate(). 198 */ 199 200 201 extern int EXPORT deflate OF((z_streamp strm, int flush)); 202 /* 203 Performs one or both of the following actions: 204 205 - Compress more input starting at next_in and update next_in and avail_in 206 accordingly. If not all input can be processed (because there is not 207 enough room in the output buffer), next_in and avail_in are updated and 208 processing will resume at this point for the next call of deflate(). 209 210 - Provide more output starting at next_out and update next_out and avail_out 211 accordingly. This action is forced if the parameter flush is non zero. 212 Forcing flush frequently degrades the compression ratio, so this parameter 213 should be set only when necessary (in interactive applications). 214 Some output may be provided even if flush is not set. 215 216 Before the call of deflate(), the application should ensure that at least 217 one of the actions is possible, by providing more input and/or consuming 218 more output, and updating avail_in or avail_out accordingly; avail_out 219 should never be zero before the call. The application can consume the 220 compressed output when it wants, for example when the output buffer is full 221 (avail_out == 0), or after each call of deflate(). If deflate returns Z_OK 222 and with zero avail_out, it must be called again after making room in the 223 output buffer because there might be more output pending. 224 225 If the parameter flush is set to Z_PARTIAL_FLUSH, the current compression 226 block is terminated and flushed to the output buffer so that the 227 decompressor can get all input data available so far. For method 9, a future 228 variant on method 8, the current block will be flushed but not terminated. 229 Z_SYNC_FLUSH has the same effect as partial flush except that the compressed 230 output is byte aligned (the compressor can clear its internal bit buffer) 231 and the current block is always terminated; this can be useful if the 232 compressor has to be restarted from scratch after an interruption (in which 233 case the internal state of the compressor may be lost). 234 If flush is set to Z_FULL_FLUSH, the compression block is terminated, a 235 special marker is output and the compression dictionary is discarded; this 236 is useful to allow the decompressor to synchronize if one compressed block 237 has been damaged (see inflateSync below). Flushing degrades compression and 238 so should be used only when necessary. Using Z_FULL_FLUSH too often can 239 seriously degrade the compression. If deflate returns with avail_out == 0, 240 this function must be called again with the same value of the flush 241 parameter and more output space (updated avail_out), until the flush is 242 complete (deflate returns with non-zero avail_out). 243 244 If the parameter flush is set to Z_FINISH, pending input is processed, 245 pending output is flushed and deflate returns with Z_STREAM_END if there 246 was enough output space; if deflate returns with Z_OK, this function must be 247 called again with Z_FINISH and more output space (updated avail_out) but no 248 more input data, until it returns with Z_STREAM_END or an error. After 249 deflate has returned Z_STREAM_END, the only possible operations on the 250 stream are deflateReset or deflateEnd. 251 252 Z_FINISH can be used immediately after deflateInit if all the compression 253 is to be done in a single step. In this case, avail_out must be at least 254 0.1% larger than avail_in plus 12 bytes. If deflate does not return 255 Z_STREAM_END, then it must be called again as described above. 256 257 deflate() may update data_type if it can make a good guess about 258 the input data type (Z_ASCII or Z_BINARY). In doubt, the data is considered 259 binary. This field is only for information purposes and does not affect 260 the compression algorithm in any manner. 261 262 deflate() returns Z_OK if some progress has been made (more input 263 processed or more output produced), Z_STREAM_END if all input has been 264 consumed and all output has been produced (only when flush is set to 265 Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example 266 if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible. 267 */ 268 269 270 extern int EXPORT deflateEnd OF((z_streamp strm)); 271 /* 272 All dynamically allocated data structures for this stream are freed. 273 This function discards any unprocessed input and does not flush any 274 pending output. 275 276 deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the 277 stream state was inconsistent, Z_DATA_ERROR if the stream was freed 278 prematurely (some input or output was discarded). In the error case, 279 msg may be set but then points to a static string (which must not be 280 deallocated). 281 */ 282 283 284 /* 285 extern int EXPORT inflateInit OF((z_streamp strm)); 286 287 Initializes the internal stream state for decompression. The fields 288 zalloc, zfree and opaque must be initialized before by the caller. If 289 zalloc and zfree are set to Z_NULL, inflateInit updates them to use default 290 allocation functions. 291 292 inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not 293 enough memory, Z_VERSION_ERROR if the zlib library version is incompatible 294 with the version assumed by the caller. msg is set to null if there is no 295 error message. inflateInit does not perform any decompression: this will be 296 done by inflate(). 297 */ 298 299 300 extern int EXPORT inflate OF((z_streamp strm, int flush)); 301 /* 302 Performs one or both of the following actions: 303 304 - Decompress more input starting at next_in and update next_in and avail_in 305 accordingly. If not all input can be processed (because there is not 306 enough room in the output buffer), next_in is updated and processing 307 will resume at this point for the next call of inflate(). 308 309 - Provide more output starting at next_out and update next_out and avail_out 310 accordingly. inflate() provides as much output as possible, until there 311 is no more input data or no more space in the output buffer (see below 312 about the flush parameter). 313 314 Before the call of inflate(), the application should ensure that at least 315 one of the actions is possible, by providing more input and/or consuming 316 more output, and updating the next_* and avail_* values accordingly. 317 The application can consume the uncompressed output when it wants, for 318 example when the output buffer is full (avail_out == 0), or after each 319 call of inflate(). If inflate returns Z_OK and with zero avail_out, it 320 must be called again after making room in the output buffer because there 321 might be more output pending. 322 323 If the parameter flush is set to Z_PARTIAL_FLUSH, inflate flushes as much 324 output as possible to the output buffer. The flushing behavior of inflate is 325 not specified for values of the flush parameter other than Z_PARTIAL_FLUSH 326 and Z_FINISH, but the current implementation actually flushes as much output 327 as possible anyway. 328 329 inflate() should normally be called until it returns Z_STREAM_END or an 330 error. However if all decompression is to be performed in a single step 331 (a single call of inflate), the parameter flush should be set to 332 Z_FINISH. In this case all pending input is processed and all pending 333 output is flushed; avail_out must be large enough to hold all the 334 uncompressed data. (The size of the uncompressed data may have been saved 335 by the compressor for this purpose.) The next operation on this stream must 336 be inflateEnd to deallocate the decompression state. The use of Z_FINISH 337 is never required, but can be used to inform inflate that a faster routine 338 may be used for the single inflate() call. 339 340 inflate() returns Z_OK if some progress has been made (more input 341 processed or more output produced), Z_STREAM_END if the end of the 342 compressed data has been reached and all uncompressed output has been 343 produced, Z_NEED_DICT if a preset dictionary is needed at this point (see 344 inflateSetDictionary below), Z_DATA_ERROR if the input data was corrupted, 345 Z_STREAM_ERROR if the stream structure was inconsistent (for example if 346 next_in or next_out was NULL), Z_MEM_ERROR if there was not enough memory, 347 Z_BUF_ERROR if no progress is possible or if there was not enough room in 348 the output buffer when Z_FINISH is used. In the Z_DATA_ERROR case, the 349 application may then call inflateSync to look for a good compression block. 350 In the Z_NEED_DICT case, strm->adler is set to the Adler32 value of the 351 dictionary chosen by the compressor. 352 */ 353 354 355 extern int EXPORT inflateEnd OF((z_streamp strm)); 356 /* 357 All dynamically allocated data structures for this stream are freed. 358 This function discards any unprocessed input and does not flush any 359 pending output. 360 361 inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state 362 was inconsistent. In the error case, msg may be set but then points to a 363 static string (which must not be deallocated). 364 */ 365 366 /* Advanced functions */ 367 368 /* 369 The following functions are needed only in some special applications. 370 */ 371 372 /* 373 extern int EXPORT deflateInit2 OF((z_streamp strm, 374 int level, 375 int method, 376 int windowBits, 377 int memLevel, 378 int strategy)); 379 380 This is another version of deflateInit with more compression options. The 381 fields next_in, zalloc, zfree and opaque must be initialized before by 382 the caller. 383 384 The method parameter is the compression method. It must be Z_DEFLATED in 385 this version of the library. (Method 9 will allow a 64K history buffer and 386 partial block flushes.) 387 388 The windowBits parameter is the base two logarithm of the window size 389 (the size of the history buffer). It should be in the range 8..15 for this 390 version of the library (the value 16 will be allowed for method 9). Larger 391 values of this parameter result in better compression at the expense of 392 memory usage. The default value is 15 if deflateInit is used instead. 393 394 The memLevel parameter specifies how much memory should be allocated 395 for the internal compression state. memLevel=1 uses minimum memory but 396 is slow and reduces compression ratio; memLevel=9 uses maximum memory 397 for optimal speed. The default value is 8. See zconf.h for total memory 398 usage as a function of windowBits and memLevel. 399 400 The strategy parameter is used to tune the compression algorithm. Use the 401 value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a 402 filter (or predictor), or Z_HUFFMAN_ONLY to force Huffman encoding only (no 403 string match). Filtered data consists mostly of small values with a 404 somewhat random distribution. In this case, the compression algorithm is 405 tuned to compress them better. The effect of Z_FILTERED is to force more 406 Huffman coding and less string matching; it is somewhat intermediate 407 between Z_DEFAULT and Z_HUFFMAN_ONLY. The strategy parameter only affects 408 the compression ratio but not the correctness of the compressed output even 409 if it is not set appropriately. 410 411 If next_in is not null, the library will use this buffer to hold also 412 some history information; the buffer must either hold the entire input 413 data, or have at least 1<<(windowBits+1) bytes and be writable. If next_in 414 is null, the library will allocate its own history buffer (and leave next_in 415 null). next_out need not be provided here but must be provided by the 416 application for the next call of deflate(). 417 418 If the history buffer is provided by the application, next_in must 419 must never be changed by the application since the compressor maintains 420 information inside this buffer from call to call; the application 421 must provide more input only by increasing avail_in. next_in is always 422 reset by the library in this case. 423 424 deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was 425 not enough memory, Z_STREAM_ERROR if a parameter is invalid (such as 426 an invalid method). msg is set to null if there is no error message. 427 deflateInit2 does not perform any compression: this will be done by 428 deflate(). 429 */ 430 431 extern int EXPORT deflateSetDictionary OF((z_streamp strm, 432 const Bytef *dictionary, 433 uInt dictLength)); 434 /* 435 Initializes the compression dictionary (history buffer) from the given 436 byte sequence without producing any compressed output. This function must 437 be called immediately after deflateInit or deflateInit2, before any call 438 of deflate. The compressor and decompressor must use exactly the same 439 dictionary (see inflateSetDictionary). 440 The dictionary should consist of strings (byte sequences) that are likely 441 to be encountered later in the data to be compressed, with the most commonly 442 used strings preferably put towards the end of the dictionary. Using a 443 dictionary is most useful when the data to be compressed is short and 444 can be predicted with good accuracy; the data can then be compressed better 445 than with the default empty dictionary. In this version of the library, 446 only the last 32K bytes of the dictionary are used. 447 Upon return of this function, strm->adler is set to the Adler32 value 448 of the dictionary; the decompressor may later use this value to determine 449 which dictionary has been used by the compressor. (The Adler32 value 450 applies to the whole dictionary even if only a subset of the dictionary is 451 actually used by the compressor.) 452 453 deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a 454 parameter is invalid (such as NULL dictionary) or the stream state 455 is inconsistent (for example if deflate has already been called for this 456 stream). deflateSetDictionary does not perform any compression: this will 457 be done by deflate(). 458 */ 459 460 extern int EXPORT deflateCopy OF((z_streamp dest, 461 z_streamp source)); 462 /* 463 Sets the destination stream as a complete copy of the source stream. If 464 the source stream is using an application-supplied history buffer, a new 465 buffer is allocated for the destination stream. The compressed output 466 buffer is always application-supplied. It's the responsibility of the 467 application to provide the correct values of next_out and avail_out for the 468 next call of deflate. 469 470 This function can be useful when several compression strategies will be 471 tried, for example when there are several ways of pre-processing the input 472 data with a filter. The streams that will be discarded should then be freed 473 by calling deflateEnd. Note that deflateCopy duplicates the internal 474 compression state which can be quite large, so this strategy is slow and 475 can consume lots of memory. 476 477 deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not 478 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent 479 (such as zalloc being NULL). msg is left unchanged in both source and 480 destination. 481 */ 482 483 extern int EXPORT deflateReset OF((z_streamp strm)); 484 /* 485 This function is equivalent to deflateEnd followed by deflateInit, 486 but does not free and reallocate all the internal compression state. 487 The stream will keep the same compression level and any other attributes 488 that may have been set by deflateInit2. 489 490 deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source 491 stream state was inconsistent (such as zalloc or state being NULL). 492 */ 493 494 extern int EXPORT deflateParams OF((z_streamp strm, int level, int strategy)); 495 /* 496 Dynamically update the compression level and compression strategy. 497 This can be used to switch between compression and straight copy of 498 the input data, or to switch to a different kind of input data requiring 499 a different strategy. If the compression level is changed, the input 500 available so far is compressed with the old level (and may be flushed); 501 the new level will take effect only at the next call of deflate(). 502 503 Before the call of deflateParams, the stream state must be set as for 504 a call of deflate(), since the currently available input may have to 505 be compressed and flushed. In particular, strm->avail_out must be non-zero. 506 507 deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source 508 stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR 509 if strm->avail_out was zero. 510 */ 511 512 /* 513 extern int EXPORT inflateInit2 OF((z_streamp strm, 514 int windowBits)); 515 516 This is another version of inflateInit with more compression options. The 517 fields next_out, zalloc, zfree and opaque must be initialized before by 518 the caller. 519 520 The windowBits parameter is the base two logarithm of the maximum window 521 size (the size of the history buffer). It should be in the range 8..15 for 522 this version of the library (the value 16 will be allowed soon). The 523 default value is 15 if inflateInit is used instead. If a compressed stream 524 with a larger window size is given as input, inflate() will return with 525 the error code Z_DATA_ERROR instead of trying to allocate a larger window. 526 527 If next_out is not null, the library will use this buffer for the history 528 buffer; the buffer must either be large enough to hold the entire output 529 data, or have at least 1<<windowBits bytes. If next_out is null, the 530 library will allocate its own buffer (and leave next_out null). next_in 531 need not be provided here but must be provided by the application for the 532 next call of inflate(). 533 534 If the history buffer is provided by the application, next_out must 535 never be changed by the application since the decompressor maintains 536 history information inside this buffer from call to call; the application 537 can only reset next_out to the beginning of the history buffer when 538 avail_out is zero and all output has been consumed. 539 540 inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was 541 not enough memory, Z_STREAM_ERROR if a parameter is invalid (such as 542 windowBits < 8). msg is set to null if there is no error message. 543 inflateInit2 does not perform any decompression: this will be done by 544 inflate(). 545 */ 546 547 extern int EXPORT inflateSetDictionary OF((z_streamp strm, 548 const Bytef *dictionary, 549 uInt dictLength)); 550 /* 551 Initializes the decompression dictionary (history buffer) from the given 552 uncompressed byte sequence. This function must be called immediately after 553 a call of inflate if this call returned Z_NEED_DICT. The dictionary chosen 554 by the compressor can be determined from the Adler32 value returned by this 555 call of inflate. The compressor and decompressor must use exactly the same 556 dictionary (see deflateSetDictionary). 557 558 inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a 559 parameter is invalid (such as NULL dictionary) or the stream state is 560 inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the 561 expected one (incorrect Adler32 value). inflateSetDictionary does not 562 perform any decompression: this will be done by subsequent calls of 563 inflate(). 564 */ 565 566 extern int EXPORT inflateSync OF((z_streamp strm)); 567 /* 568 Skips invalid compressed data until the special marker (see deflate() 569 above) can be found, or until all available input is skipped. No output 570 is provided. 571 572 inflateSync returns Z_OK if the special marker has been found, Z_BUF_ERROR 573 if no more input was provided, Z_DATA_ERROR if no marker has been found, 574 or Z_STREAM_ERROR if the stream structure was inconsistent. In the success 575 case, the application may save the current current value of total_in which 576 indicates where valid compressed data was found. In the error case, the 577 application may repeatedly call inflateSync, providing more input each time, 578 until success or end of the input data. 579 */ 580 581 extern int EXPORT inflateReset OF((z_streamp strm)); 582 /* 583 This function is equivalent to inflateEnd followed by inflateInit, 584 but does not free and reallocate all the internal decompression state. 585 The stream will keep attributes that may have been set by inflateInit2. 586 587 inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source 588 stream state was inconsistent (such as zalloc or state being NULL). 589 */ 590 591 592 /* utility functions */ 593 594 /* 595 The following utility functions are implemented on top of the 596 basic stream-oriented functions. To simplify the interface, some 597 default options are assumed (compression level, window size, 598 standard memory allocation functions). The source code of these 599 utility functions can easily be modified if you need special options. 600 */ 601 602 extern int EXPORT compress OF((Bytef *dest, uLongf *destLen, 603 const Bytef *source, uLong sourceLen)); 604 /* 605 Compresses the source buffer into the destination buffer. sourceLen is 606 the byte length of the source buffer. Upon entry, destLen is the total 607 size of the destination buffer, which must be at least 0.1% larger than 608 sourceLen plus 12 bytes. Upon exit, destLen is the actual size of the 609 compressed buffer. 610 This function can be used to compress a whole file at once if the 611 input file is mmap'ed. 612 compress returns Z_OK if success, Z_MEM_ERROR if there was not 613 enough memory, Z_BUF_ERROR if there was not enough room in the output 614 buffer. 615 */ 616 617 extern int EXPORT uncompress OF((Bytef *dest, uLongf *destLen, 618 const Bytef *source, uLong sourceLen)); 619 /* 620 Decompresses the source buffer into the destination buffer. sourceLen is 621 the byte length of the source buffer. Upon entry, destLen is the total 622 size of the destination buffer, which must be large enough to hold the 623 entire uncompressed data. (The size of the uncompressed data must have 624 been saved previously by the compressor and transmitted to the decompressor 625 by some mechanism outside the scope of this compression library.) 626 Upon exit, destLen is the actual size of the compressed buffer. 627 This function can be used to decompress a whole file at once if the 628 input file is mmap'ed. 629 630 uncompress returns Z_OK if success, Z_MEM_ERROR if there was not 631 enough memory, Z_BUF_ERROR if there was not enough room in the output 632 buffer, or Z_DATA_ERROR if the input data was corrupted. 633 */ 634 635 636 typedef voidp gzFile; 637 638 extern gzFile EXPORT gzopen OF((const char *path, const char *mode)); 639 /* 640 Opens a gzip (.gz) file for reading or writing. The mode parameter 641 is as in fopen ("rb" or "wb") but can also include a compression level 642 ("wb9"). gzopen can be used to read a file which is not in gzip format; 643 in this case gzread will directly read from the file without decompression. 644 gzopen returns NULL if the file could not be opened or if there was 645 insufficient memory to allocate the (de)compression state; errno 646 can be checked to distinguish the two cases (if errno is zero, the 647 zlib error is Z_MEM_ERROR). 648 */ 649 650 extern gzFile EXPORT gzdopen OF((int fd, const char *mode)); 651 /* 652 gzdopen() associates a gzFile with the file descriptor fd. File 653 descriptors are obtained from calls like open, dup, creat, pipe or 654 fileno (in the file has been previously opened with fopen). 655 The mode parameter is as in gzopen. 656 The next call of gzclose on the returned gzFile will also close the 657 file descriptor fd, just like fclose(fdopen(fd), mode) closes the file 658 descriptor fd. If you want to keep fd open, use gzdopen(dup(fd), mode). 659 gzdopen returns NULL if there was insufficient memory to allocate 660 the (de)compression state. 661 */ 662 663 extern int EXPORT gzread OF((gzFile file, voidp buf, unsigned len)); 664 /* 665 Reads the given number of uncompressed bytes from the compressed file. 666 If the input file was not in gzip format, gzread copies the given number 667 of bytes into the buffer. 668 gzread returns the number of uncompressed bytes actually read (0 for 669 end of file, -1 for error). */ 670 671 extern int EXPORT gzwrite OF((gzFile file, const voidp buf, unsigned len)); 672 /* 673 Writes the given number of uncompressed bytes into the compressed file. 674 gzwrite returns the number of uncompressed bytes actually written 675 (0 in case of error). 676 */ 677 678 extern int EXPORT gzflush OF((gzFile file, int flush)); 679 /* 680 Flushes all pending output into the compressed file. The parameter 681 flush is as in the deflate() function. The return value is the zlib 682 error number (see function gzerror below). gzflush returns Z_OK if 683 the flush parameter is Z_FINISH and all output could be flushed. 684 gzflush should be called only when strictly necessary because it can 685 degrade compression. 686 */ 687 688 extern int EXPORT gzclose OF((gzFile file)); 689 /* 690 Flushes all pending output if necessary, closes the compressed file 691 and deallocates all the (de)compression state. The return value is the zlib 692 error number (see function gzerror below). 693 */ 694 695 extern const char * EXPORT gzerror OF((gzFile file, int *errnum)); 696 /* 697 Returns the error message for the last error which occurred on the 698 given compressed file. errnum is set to zlib error number. If an 699 error occurred in the file system and not in the compression library, 700 errnum is set to Z_ERRNO and the application may consult errno 701 to get the exact error code. 702 */ 703 704 /* checksum functions */ 705 706 /* 707 These functions are not related to compression but are exported 708 anyway because they might be useful in applications using the 709 compression library. 710 */ 711 712 extern uLong EXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len)); 713 714 /* 715 Update a running Adler-32 checksum with the bytes buf[0..len-1] and 716 return the updated checksum. If buf is NULL, this function returns 717 the required initial value for the checksum. 718 An Adler-32 checksum is almost as reliable as a CRC32 but can be computed 719 much faster. Usage example: 720 721 uLong adler = adler32(0L, Z_NULL, 0); 722 723 while (read_buffer(buffer, length) != EOF) { 724 adler = adler32(adler, buffer, length); 725 } 726 if (adler != original_adler) error(); 727 */ 728 729 extern uLong EXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len)); 730 /* 731 Update a running crc with the bytes buf[0..len-1] and return the updated 732 crc. If buf is NULL, this function returns the required initial value 733 for the crc. Pre- and post-conditioning (one's complement) is performed 734 within this function so it shouldn't be done by the application. 735 Usage example: 736 737 uLong crc = crc32(0L, Z_NULL, 0); 738 739 while (read_buffer(buffer, length) != EOF) { 740 crc = crc32(crc, buffer, length); 741 } 742 if (crc != original_crc) error(); 743 */ 744 745 746 /* various hacks, don't look :) */ 747 748 /* deflateInit and inflateInit are macros to allow checking the zlib version 749 * and the compiler's view of z_stream: 750 */ 751 extern int EXPORT deflateInit_ OF((z_streamp strm, int level, 752 const char *version, int stream_size)); 753 extern int EXPORT inflateInit_ OF((z_streamp strm, 754 const char *version, int stream_size)); 755 extern int EXPORT deflateInit2_ OF((z_streamp strm, int level, int method, 756 int windowBits, int memLevel, int strategy, 757 const char *version, int stream_size)); 758 extern int EXPORT inflateInit2_ OF((z_streamp strm, int windowBits, 759 const char *version, int stream_size)); 760 #define deflateInit(strm, level) \ 761 deflateInit_((strm), (level), ZLIB_VERSION, sizeof(z_stream)) 762 #define inflateInit(strm) \ 763 inflateInit_((strm), ZLIB_VERSION, sizeof(z_stream)) 764 #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \ 765 deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\ 766 (strategy), ZLIB_VERSION, sizeof(z_stream)) 767 #define inflateInit2(strm, windowBits) \ 768 inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream)) 769 770 #if !defined(_Z_UTIL_H) && !defined(NO_DUMMY_DECL) 771 struct internal_state {int dummy;}; /* hack for buggy compilers */ 772 #endif 773 774 uLongf *get_crc_table OF((void)); /* can be used by asm versions of crc32() */ 775 776 #ifdef __cplusplus 777 } 778 #endif 779 780 #endif /* _ZLIB_H */ 781