1 /* zlib.h -- interface of the 'zlib' general purpose compression library 2 version 1.2.3, July 18th, 2005 3 4 Copyright (C) 1995-2005 Jean-loup Gailly and Mark Adler 5 6 This software is provided 'as-is', without any express or implied 7 warranty. In no event will the authors be held liable for any damages 8 arising from the use of this software. 9 10 Permission is granted to anyone to use this software for any purpose, 11 including commercial applications, and to alter it and redistribute it 12 freely, subject to the following restrictions: 13 14 1. The origin of this software must not be misrepresented; you must not 15 claim that you wrote the original software. If you use this software 16 in a product, an acknowledgment in the product documentation would be 17 appreciated but is not required. 18 2. Altered source versions must be plainly marked as such, and must not be 19 misrepresented as being the original software. 20 3. This notice may not be removed or altered from any source distribution. 21 22 Jean-loup Gailly Mark Adler 23 jloup (at) gzip.org madler (at) alumni.caltech.edu 24 25 26 The data format used by the zlib library is described by RFCs (Request for 27 Comments) 1950 to 1952 in the files http://www.ietf.org/rfc/rfc1950.txt 28 (zlib format), rfc1951.txt (deflate format) and rfc1952.txt (gzip format). 29 */ 30 31 #ifndef ZLIB_H 32 #define ZLIB_H 33 34 #include "zconf.h" 35 36 #ifdef __cplusplus 37 extern "C" { 38 #endif 39 40 #define ZLIB_VERSION "1.2.3" 41 #define ZLIB_VERNUM 0x1230 42 43 /* 44 The 'zlib' compression library provides in-memory compression and 45 decompression functions, including integrity checks of the uncompressed 46 data. This version of the library supports only one compression method 47 (deflation) but other algorithms will be added later and will have the same 48 stream interface. 49 50 Compression can be done in a single step if the buffers are large 51 enough (for example if an input file is mmap'ed), or can be done by 52 repeated calls of the compression function. In the latter case, the 53 application must provide more input and/or consume the output 54 (providing more output space) before each call. 55 56 The compressed data format used by default by the in-memory functions is 57 the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped 58 around a deflate stream, which is itself documented in RFC 1951. 59 60 The library also supports reading and writing files in gzip (.gz) format 61 with an interface similar to that of stdio using the functions that start 62 with "gz". The gzip format is different from the zlib format. gzip is a 63 gzip wrapper, documented in RFC 1952, wrapped around a deflate stream. 64 65 This library can optionally read and write gzip streams in memory as well. 66 67 The zlib format was designed to be compact and fast for use in memory 68 and on communications channels. The gzip format was designed for single- 69 file compression on file systems, has a larger header than zlib to maintain 70 directory information, and uses a different, slower check method than zlib. 71 72 The library does not install any signal handler. The decoder checks 73 the consistency of the compressed data, so the library should never 74 crash even in case of corrupted input. 75 */ 76 77 typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size)); 78 typedef void (*free_func) OF((voidpf opaque, voidpf address)); 79 80 struct internal_state; 81 82 typedef struct z_stream_s { 83 Bytef *next_in; /* next input byte */ 84 uInt avail_in; /* number of bytes available at next_in */ 85 uLong total_in; /* total nb of input bytes read so far */ 86 87 Bytef *next_out; /* next output byte should be put there */ 88 uInt avail_out; /* remaining free space at next_out */ 89 uLong total_out; /* total nb of bytes output so far */ 90 91 char *msg; /* last error message, NULL if no error */ 92 struct internal_state FAR *state; /* not visible by applications */ 93 94 alloc_func zalloc; /* used to allocate the internal state */ 95 free_func zfree; /* used to free the internal state */ 96 voidpf opaque; /* private data object passed to zalloc and zfree */ 97 98 int data_type; /* best guess about the data type: binary or text */ 99 uLong adler; /* adler32 value of the uncompressed data */ 100 uLong reserved; /* reserved for future use */ 101 } z_stream; 102 103 typedef z_stream FAR *z_streamp; 104 105 /* 106 gzip header information passed to and from zlib routines. See RFC 1952 107 for more details on the meanings of these fields. 108 */ 109 typedef struct gz_header_s { 110 int text; /* true if compressed data believed to be text */ 111 uLong time; /* modification time */ 112 int xflags; /* extra flags (not used when writing a gzip file) */ 113 int os; /* operating system */ 114 Bytef *extra; /* pointer to extra field or Z_NULL if none */ 115 uInt extra_len; /* extra field length (valid if extra != Z_NULL) */ 116 uInt extra_max; /* space at extra (only when reading header) */ 117 Bytef *name; /* pointer to zero-terminated file name or Z_NULL */ 118 uInt name_max; /* space at name (only when reading header) */ 119 Bytef *comment; /* pointer to zero-terminated comment or Z_NULL */ 120 uInt comm_max; /* space at comment (only when reading header) */ 121 int hcrc; /* true if there was or will be a header crc */ 122 int done; /* true when done reading gzip header (not used 123 when writing a gzip file) */ 124 } gz_header; 125 126 typedef gz_header FAR *gz_headerp; 127 128 /* 129 The application must update next_in and avail_in when avail_in has 130 dropped to zero. It must update next_out and avail_out when avail_out 131 has dropped to zero. The application must initialize zalloc, zfree and 132 opaque before calling the init function. All other fields are set by the 133 compression library and must not be updated by the application. 134 135 The opaque value provided by the application will be passed as the first 136 parameter for calls of zalloc and zfree. This can be useful for custom 137 memory management. The compression library attaches no meaning to the 138 opaque value. 139 140 zalloc must return Z_NULL if there is not enough memory for the object. 141 If zlib is used in a multi-threaded application, zalloc and zfree must be 142 thread safe. 143 144 On 16-bit systems, the functions zalloc and zfree must be able to allocate 145 exactly 65536 bytes, but will not be required to allocate more than this 146 if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, 147 pointers returned by zalloc for objects of exactly 65536 bytes *must* 148 have their offset normalized to zero. The default allocation function 149 provided by this library ensures this (see zutil.c). To reduce memory 150 requirements and avoid any allocation of 64K objects, at the expense of 151 compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h). 152 153 The fields total_in and total_out can be used for statistics or 154 progress reports. After compression, total_in holds the total size of 155 the uncompressed data and may be saved for use in the decompressor 156 (particularly if the decompressor wants to decompress everything in 157 a single step). 158 */ 159 160 /* constants */ 161 162 #define Z_NO_FLUSH 0 163 #define Z_PARTIAL_FLUSH 1 /* will be removed, use Z_SYNC_FLUSH instead */ 164 #define Z_SYNC_FLUSH 2 165 #define Z_FULL_FLUSH 3 166 #define Z_FINISH 4 167 #define Z_BLOCK 5 168 /* Allowed flush values; see deflate() and inflate() below for details */ 169 170 #define Z_OK 0 171 #define Z_STREAM_END 1 172 #define Z_NEED_DICT 2 173 #define Z_ERRNO (-1) 174 #define Z_STREAM_ERROR (-2) 175 #define Z_DATA_ERROR (-3) 176 #define Z_MEM_ERROR (-4) 177 #define Z_BUF_ERROR (-5) 178 #define Z_VERSION_ERROR (-6) 179 /* Return codes for the compression/decompression functions. Negative 180 * values are errors, positive values are used for special but normal events. 181 */ 182 183 #define Z_NO_COMPRESSION 0 184 #define Z_BEST_SPEED 1 185 #define Z_BEST_COMPRESSION 9 186 #define Z_DEFAULT_COMPRESSION (-1) 187 /* compression levels */ 188 189 #define Z_FILTERED 1 190 #define Z_HUFFMAN_ONLY 2 191 #define Z_RLE 3 192 #define Z_FIXED 4 193 #define Z_DEFAULT_STRATEGY 0 194 /* compression strategy; see deflateInit2() below for details */ 195 196 #define Z_BINARY 0 197 #define Z_TEXT 1 198 #define Z_ASCII Z_TEXT /* for compatibility with 1.2.2 and earlier */ 199 #define Z_UNKNOWN 2 200 /* Possible values of the data_type field (though see inflate()) */ 201 202 #define Z_DEFLATED 8 203 /* The deflate compression method (the only one supported in this version) */ 204 205 #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */ 206 207 #define zlib_version zlibVersion() 208 /* for compatibility with versions < 1.0.2 */ 209 210 /* basic functions */ 211 212 ZEXTERN const char * ZEXPORT zlibVersion OF((void)); 213 /* The application can compare zlibVersion and ZLIB_VERSION for consistency. 214 If the first character differs, the library code actually used is 215 not compatible with the zlib.h header file used by the application. 216 This check is automatically made by deflateInit and inflateInit. 217 */ 218 219 /* 220 ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level)); 221 222 Initializes the internal stream state for compression. The fields 223 zalloc, zfree and opaque must be initialized before by the caller. 224 If zalloc and zfree are set to Z_NULL, deflateInit updates them to 225 use default allocation functions. 226 227 The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9: 228 1 gives best speed, 9 gives best compression, 0 gives no compression at 229 all (the input data is simply copied a block at a time). 230 Z_DEFAULT_COMPRESSION requests a default compromise between speed and 231 compression (currently equivalent to level 6). 232 233 deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not 234 enough memory, Z_STREAM_ERROR if level is not a valid compression level, 235 Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible 236 with the version assumed by the caller (ZLIB_VERSION). 237 msg is set to null if there is no error message. deflateInit does not 238 perform any compression: this will be done by deflate(). 239 */ 240 241 242 ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush)); 243 /* 244 deflate compresses as much data as possible, and stops when the input 245 buffer becomes empty or the output buffer becomes full. It may introduce some 246 output latency (reading input without producing any output) except when 247 forced to flush. 248 249 The detailed semantics are as follows. deflate performs one or both of the 250 following actions: 251 252 - Compress more input starting at next_in and update next_in and avail_in 253 accordingly. If not all input can be processed (because there is not 254 enough room in the output buffer), next_in and avail_in are updated and 255 processing will resume at this point for the next call of deflate(). 256 257 - Provide more output starting at next_out and update next_out and avail_out 258 accordingly. This action is forced if the parameter flush is non zero. 259 Forcing flush frequently degrades the compression ratio, so this parameter 260 should be set only when necessary (in interactive applications). 261 Some output may be provided even if flush is not set. 262 263 Before the call of deflate(), the application should ensure that at least 264 one of the actions is possible, by providing more input and/or consuming 265 more output, and updating avail_in or avail_out accordingly; avail_out 266 should never be zero before the call. The application can consume the 267 compressed output when it wants, for example when the output buffer is full 268 (avail_out == 0), or after each call of deflate(). If deflate returns Z_OK 269 and with zero avail_out, it must be called again after making room in the 270 output buffer because there might be more output pending. 271 272 Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to 273 decide how much data to accumualte before producing output, in order to 274 maximize compression. 275 276 If the parameter flush is set to Z_SYNC_FLUSH, all pending output is 277 flushed to the output buffer and the output is aligned on a byte boundary, so 278 that the decompressor can get all input data available so far. (In particular 279 avail_in is zero after the call if enough output space has been provided 280 before the call.) Flushing may degrade compression for some compression 281 algorithms and so it should be used only when necessary. 282 283 If flush is set to Z_FULL_FLUSH, all output is flushed as with 284 Z_SYNC_FLUSH, and the compression state is reset so that decompression can 285 restart from this point if previous compressed data has been damaged or if 286 random access is desired. Using Z_FULL_FLUSH too often can seriously degrade 287 compression. 288 289 If deflate returns with avail_out == 0, this function must be called again 290 with the same value of the flush parameter and more output space (updated 291 avail_out), until the flush is complete (deflate returns with non-zero 292 avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that 293 avail_out is greater than six to avoid repeated flush markers due to 294 avail_out == 0 on return. 295 296 If the parameter flush is set to Z_FINISH, pending input is processed, 297 pending output is flushed and deflate returns with Z_STREAM_END if there 298 was enough output space; if deflate returns with Z_OK, this function must be 299 called again with Z_FINISH and more output space (updated avail_out) but no 300 more input data, until it returns with Z_STREAM_END or an error. After 301 deflate has returned Z_STREAM_END, the only possible operations on the 302 stream are deflateReset or deflateEnd. 303 304 Z_FINISH can be used immediately after deflateInit if all the compression 305 is to be done in a single step. In this case, avail_out must be at least 306 the value returned by deflateBound (see below). If deflate does not return 307 Z_STREAM_END, then it must be called again as described above. 308 309 deflate() sets strm->adler to the adler32 checksum of all input read 310 so far (that is, total_in bytes). 311 312 deflate() may update strm->data_type if it can make a good guess about 313 the input data type (Z_BINARY or Z_TEXT). In doubt, the data is considered 314 binary. This field is only for information purposes and does not affect 315 the compression algorithm in any manner. 316 317 deflate() returns Z_OK if some progress has been made (more input 318 processed or more output produced), Z_STREAM_END if all input has been 319 consumed and all output has been produced (only when flush is set to 320 Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example 321 if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible 322 (for example avail_in or avail_out was zero). Note that Z_BUF_ERROR is not 323 fatal, and deflate() can be called again with more input and more output 324 space to continue compressing. 325 */ 326 327 328 ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm)); 329 /* 330 All dynamically allocated data structures for this stream are freed. 331 This function discards any unprocessed input and does not flush any 332 pending output. 333 334 deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the 335 stream state was inconsistent, Z_DATA_ERROR if the stream was freed 336 prematurely (some input or output was discarded). In the error case, 337 msg may be set but then points to a static string (which must not be 338 deallocated). 339 */ 340 341 342 /* 343 ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm)); 344 345 Initializes the internal stream state for decompression. The fields 346 next_in, avail_in, zalloc, zfree and opaque must be initialized before by 347 the caller. If next_in is not Z_NULL and avail_in is large enough (the exact 348 value depends on the compression method), inflateInit determines the 349 compression method from the zlib header and allocates all data structures 350 accordingly; otherwise the allocation will be deferred to the first call of 351 inflate. If zalloc and zfree are set to Z_NULL, inflateInit updates them to 352 use default allocation functions. 353 354 inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough 355 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the 356 version assumed by the caller. msg is set to null if there is no error 357 message. inflateInit does not perform any decompression apart from reading 358 the zlib header if present: this will be done by inflate(). (So next_in and 359 avail_in may be modified, but next_out and avail_out are unchanged.) 360 */ 361 362 363 ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush)); 364 /* 365 inflate decompresses as much data as possible, and stops when the input 366 buffer becomes empty or the output buffer becomes full. It may introduce 367 some output latency (reading input without producing any output) except when 368 forced to flush. 369 370 The detailed semantics are as follows. inflate performs one or both of the 371 following actions: 372 373 - Decompress more input starting at next_in and update next_in and avail_in 374 accordingly. If not all input can be processed (because there is not 375 enough room in the output buffer), next_in is updated and processing 376 will resume at this point for the next call of inflate(). 377 378 - Provide more output starting at next_out and update next_out and avail_out 379 accordingly. inflate() provides as much output as possible, until there 380 is no more input data or no more space in the output buffer (see below 381 about the flush parameter). 382 383 Before the call of inflate(), the application should ensure that at least 384 one of the actions is possible, by providing more input and/or consuming 385 more output, and updating the next_* and avail_* values accordingly. 386 The application can consume the uncompressed output when it wants, for 387 example when the output buffer is full (avail_out == 0), or after each 388 call of inflate(). If inflate returns Z_OK and with zero avail_out, it 389 must be called again after making room in the output buffer because there 390 might be more output pending. 391 392 The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, 393 Z_FINISH, or Z_BLOCK. Z_SYNC_FLUSH requests that inflate() flush as much 394 output as possible to the output buffer. Z_BLOCK requests that inflate() stop 395 if and when it gets to the next deflate block boundary. When decoding the 396 zlib or gzip format, this will cause inflate() to return immediately after 397 the header and before the first block. When doing a raw inflate, inflate() 398 will go ahead and process the first block, and will return when it gets to 399 the end of that block, or when it runs out of data. 400 401 The Z_BLOCK option assists in appending to or combining deflate streams. 402 Also to assist in this, on return inflate() will set strm->data_type to the 403 number of unused bits in the last byte taken from strm->next_in, plus 64 404 if inflate() is currently decoding the last block in the deflate stream, 405 plus 128 if inflate() returned immediately after decoding an end-of-block 406 code or decoding the complete header up to just before the first byte of the 407 deflate stream. The end-of-block will not be indicated until all of the 408 uncompressed data from that block has been written to strm->next_out. The 409 number of unused bits may in general be greater than seven, except when 410 bit 7 of data_type is set, in which case the number of unused bits will be 411 less than eight. 412 413 inflate() should normally be called until it returns Z_STREAM_END or an 414 error. However if all decompression is to be performed in a single step 415 (a single call of inflate), the parameter flush should be set to 416 Z_FINISH. In this case all pending input is processed and all pending 417 output is flushed; avail_out must be large enough to hold all the 418 uncompressed data. (The size of the uncompressed data may have been saved 419 by the compressor for this purpose.) The next operation on this stream must 420 be inflateEnd to deallocate the decompression state. The use of Z_FINISH 421 is never required, but can be used to inform inflate that a faster approach 422 may be used for the single inflate() call. 423 424 In this implementation, inflate() always flushes as much output as 425 possible to the output buffer, and always uses the faster approach on the 426 first call. So the only effect of the flush parameter in this implementation 427 is on the return value of inflate(), as noted below, or when it returns early 428 because Z_BLOCK is used. 429 430 If a preset dictionary is needed after this call (see inflateSetDictionary 431 below), inflate sets strm->adler to the adler32 checksum of the dictionary 432 chosen by the compressor and returns Z_NEED_DICT; otherwise it sets 433 strm->adler to the adler32 checksum of all output produced so far (that is, 434 total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described 435 below. At the end of the stream, inflate() checks that its computed adler32 436 checksum is equal to that saved by the compressor and returns Z_STREAM_END 437 only if the checksum is correct. 438 439 inflate() will decompress and check either zlib-wrapped or gzip-wrapped 440 deflate data. The header type is detected automatically. Any information 441 contained in the gzip header is not retained, so applications that need that 442 information should instead use raw inflate, see inflateInit2() below, or 443 inflateBack() and perform their own processing of the gzip header and 444 trailer. 445 446 inflate() returns Z_OK if some progress has been made (more input processed 447 or more output produced), Z_STREAM_END if the end of the compressed data has 448 been reached and all uncompressed output has been produced, Z_NEED_DICT if a 449 preset dictionary is needed at this point, Z_DATA_ERROR if the input data was 450 corrupted (input stream not conforming to the zlib format or incorrect check 451 value), Z_STREAM_ERROR if the stream structure was inconsistent (for example 452 if next_in or next_out was NULL), Z_MEM_ERROR if there was not enough memory, 453 Z_BUF_ERROR if no progress is possible or if there was not enough room in the 454 output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and 455 inflate() can be called again with more input and more output space to 456 continue decompressing. If Z_DATA_ERROR is returned, the application may then 457 call inflateSync() to look for a good compression block if a partial recovery 458 of the data is desired. 459 */ 460 461 462 ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm)); 463 /* 464 All dynamically allocated data structures for this stream are freed. 465 This function discards any unprocessed input and does not flush any 466 pending output. 467 468 inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state 469 was inconsistent. In the error case, msg may be set but then points to a 470 static string (which must not be deallocated). 471 */ 472 473 /* Advanced functions */ 474 475 /* 476 The following functions are needed only in some special applications. 477 */ 478 479 /* 480 ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm, 481 int level, 482 int method, 483 int windowBits, 484 int memLevel, 485 int strategy)); 486 487 This is another version of deflateInit with more compression options. The 488 fields next_in, zalloc, zfree and opaque must be initialized before by 489 the caller. 490 491 The method parameter is the compression method. It must be Z_DEFLATED in 492 this version of the library. 493 494 The windowBits parameter is the base two logarithm of the window size 495 (the size of the history buffer). It should be in the range 8..15 for this 496 version of the library. Larger values of this parameter result in better 497 compression at the expense of memory usage. The default value is 15 if 498 deflateInit is used instead. 499 500 windowBits can also be -8..-15 for raw deflate. In this case, -windowBits 501 determines the window size. deflate() will then generate raw deflate data 502 with no zlib header or trailer, and will not compute an adler32 check value. 503 504 windowBits can also be greater than 15 for optional gzip encoding. Add 505 16 to windowBits to write a simple gzip header and trailer around the 506 compressed data instead of a zlib wrapper. The gzip header will have no 507 file name, no extra data, no comment, no modification time (set to zero), 508 no header crc, and the operating system will be set to 255 (unknown). If a 509 gzip stream is being written, strm->adler is a crc32 instead of an adler32. 510 511 The memLevel parameter specifies how much memory should be allocated 512 for the internal compression state. memLevel=1 uses minimum memory but 513 is slow and reduces compression ratio; memLevel=9 uses maximum memory 514 for optimal speed. The default value is 8. See zconf.h for total memory 515 usage as a function of windowBits and memLevel. 516 517 The strategy parameter is used to tune the compression algorithm. Use the 518 value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a 519 filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no 520 string match), or Z_RLE to limit match distances to one (run-length 521 encoding). Filtered data consists mostly of small values with a somewhat 522 random distribution. In this case, the compression algorithm is tuned to 523 compress them better. The effect of Z_FILTERED is to force more Huffman 524 coding and less string matching; it is somewhat intermediate between 525 Z_DEFAULT and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as fast as 526 Z_HUFFMAN_ONLY, but give better compression for PNG image data. The strategy 527 parameter only affects the compression ratio but not the correctness of the 528 compressed output even if it is not set appropriately. Z_FIXED prevents the 529 use of dynamic Huffman codes, allowing for a simpler decoder for special 530 applications. 531 532 deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 533 memory, Z_STREAM_ERROR if a parameter is invalid (such as an invalid 534 method). msg is set to null if there is no error message. deflateInit2 does 535 not perform any compression: this will be done by deflate(). 536 */ 537 538 ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm, 539 const Bytef *dictionary, 540 uInt dictLength)); 541 /* 542 Initializes the compression dictionary from the given byte sequence 543 without producing any compressed output. This function must be called 544 immediately after deflateInit, deflateInit2 or deflateReset, before any 545 call of deflate. The compressor and decompressor must use exactly the same 546 dictionary (see inflateSetDictionary). 547 548 The dictionary should consist of strings (byte sequences) that are likely 549 to be encountered later in the data to be compressed, with the most commonly 550 used strings preferably put towards the end of the dictionary. Using a 551 dictionary is most useful when the data to be compressed is short and can be 552 predicted with good accuracy; the data can then be compressed better than 553 with the default empty dictionary. 554 555 Depending on the size of the compression data structures selected by 556 deflateInit or deflateInit2, a part of the dictionary may in effect be 557 discarded, for example if the dictionary is larger than the window size in 558 deflate or deflate2. Thus the strings most likely to be useful should be 559 put at the end of the dictionary, not at the front. In addition, the 560 current implementation of deflate will use at most the window size minus 561 262 bytes of the provided dictionary. 562 563 Upon return of this function, strm->adler is set to the adler32 value 564 of the dictionary; the decompressor may later use this value to determine 565 which dictionary has been used by the compressor. (The adler32 value 566 applies to the whole dictionary even if only a subset of the dictionary is 567 actually used by the compressor.) If a raw deflate was requested, then the 568 adler32 value is not computed and strm->adler is not set. 569 570 deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a 571 parameter is invalid (such as NULL dictionary) or the stream state is 572 inconsistent (for example if deflate has already been called for this stream 573 or if the compression method is bsort). deflateSetDictionary does not 574 perform any compression: this will be done by deflate(). 575 */ 576 577 ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest, 578 z_streamp source)); 579 /* 580 Sets the destination stream as a complete copy of the source stream. 581 582 This function can be useful when several compression strategies will be 583 tried, for example when there are several ways of pre-processing the input 584 data with a filter. The streams that will be discarded should then be freed 585 by calling deflateEnd. Note that deflateCopy duplicates the internal 586 compression state which can be quite large, so this strategy is slow and 587 can consume lots of memory. 588 589 deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not 590 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent 591 (such as zalloc being NULL). msg is left unchanged in both source and 592 destination. 593 */ 594 595 ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm)); 596 /* 597 This function is equivalent to deflateEnd followed by deflateInit, 598 but does not free and reallocate all the internal compression state. 599 The stream will keep the same compression level and any other attributes 600 that may have been set by deflateInit2. 601 602 deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source 603 stream state was inconsistent (such as zalloc or state being NULL). 604 */ 605 606 ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm, 607 int level, 608 int strategy)); 609 /* 610 Dynamically update the compression level and compression strategy. The 611 interpretation of level and strategy is as in deflateInit2. This can be 612 used to switch between compression and straight copy of the input data, or 613 to switch to a different kind of input data requiring a different 614 strategy. If the compression level is changed, the input available so far 615 is compressed with the old level (and may be flushed); the new level will 616 take effect only at the next call of deflate(). 617 618 Before the call of deflateParams, the stream state must be set as for 619 a call of deflate(), since the currently available input may have to 620 be compressed and flushed. In particular, strm->avail_out must be non-zero. 621 622 deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source 623 stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR 624 if strm->avail_out was zero. 625 */ 626 627 ZEXTERN int ZEXPORT deflateTune OF((z_streamp strm, 628 int good_length, 629 int max_lazy, 630 int nice_length, 631 int max_chain)); 632 /* 633 Fine tune deflate's internal compression parameters. This should only be 634 used by someone who understands the algorithm used by zlib's deflate for 635 searching for the best matching string, and even then only by the most 636 fanatic optimizer trying to squeeze out the last compressed bit for their 637 specific input data. Read the deflate.c source code for the meaning of the 638 max_lazy, good_length, nice_length, and max_chain parameters. 639 640 deflateTune() can be called after deflateInit() or deflateInit2(), and 641 returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream. 642 */ 643 644 ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm, 645 uLong sourceLen)); 646 /* 647 deflateBound() returns an upper bound on the compressed size after 648 deflation of sourceLen bytes. It must be called after deflateInit() 649 or deflateInit2(). This would be used to allocate an output buffer 650 for deflation in a single pass, and so would be called before deflate(). 651 */ 652 653 ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm, 654 int bits, 655 int value)); 656 /* 657 deflatePrime() inserts bits in the deflate output stream. The intent 658 is that this function is used to start off the deflate output with the 659 bits leftover from a previous deflate stream when appending to it. As such, 660 this function can only be used for raw deflate, and must be used before the 661 first deflate() call after a deflateInit2() or deflateReset(). bits must be 662 less than or equal to 16, and that many of the least significant bits of 663 value will be inserted in the output. 664 665 deflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source 666 stream state was inconsistent. 667 */ 668 669 ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm, 670 gz_headerp head)); 671 /* 672 deflateSetHeader() provides gzip header information for when a gzip 673 stream is requested by deflateInit2(). deflateSetHeader() may be called 674 after deflateInit2() or deflateReset() and before the first call of 675 deflate(). The text, time, os, extra field, name, and comment information 676 in the provided gz_header structure are written to the gzip header (xflag is 677 ignored -- the extra flags are set according to the compression level). The 678 caller must assure that, if not Z_NULL, name and comment are terminated with 679 a zero byte, and that if extra is not Z_NULL, that extra_len bytes are 680 available there. If hcrc is true, a gzip header crc is included. Note that 681 the current versions of the command-line version of gzip (up through version 682 1.3.x) do not support header crc's, and will report that it is a "multi-part 683 gzip file" and give up. 684 685 If deflateSetHeader is not used, the default gzip header has text false, 686 the time set to zero, and os set to 255, with no extra, name, or comment 687 fields. The gzip header is returned to the default state by deflateReset(). 688 689 deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source 690 stream state was inconsistent. 691 */ 692 693 /* 694 ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm, 695 int windowBits)); 696 697 This is another version of inflateInit with an extra parameter. The 698 fields next_in, avail_in, zalloc, zfree and opaque must be initialized 699 before by the caller. 700 701 The windowBits parameter is the base two logarithm of the maximum window 702 size (the size of the history buffer). It should be in the range 8..15 for 703 this version of the library. The default value is 15 if inflateInit is used 704 instead. windowBits must be greater than or equal to the windowBits value 705 provided to deflateInit2() while compressing, or it must be equal to 15 if 706 deflateInit2() was not used. If a compressed stream with a larger window 707 size is given as input, inflate() will return with the error code 708 Z_DATA_ERROR instead of trying to allocate a larger window. 709 710 windowBits can also be -8..-15 for raw inflate. In this case, -windowBits 711 determines the window size. inflate() will then process raw deflate data, 712 not looking for a zlib or gzip header, not generating a check value, and not 713 looking for any check values for comparison at the end of the stream. This 714 is for use with other formats that use the deflate compressed data format 715 such as zip. Those formats provide their own check values. If a custom 716 format is developed using the raw deflate format for compressed data, it is 717 recommended that a check value such as an adler32 or a crc32 be applied to 718 the uncompressed data as is done in the zlib, gzip, and zip formats. For 719 most applications, the zlib format should be used as is. Note that comments 720 above on the use in deflateInit2() applies to the magnitude of windowBits. 721 722 windowBits can also be greater than 15 for optional gzip decoding. Add 723 32 to windowBits to enable zlib and gzip decoding with automatic header 724 detection, or add 16 to decode only the gzip format (the zlib format will 725 return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is 726 a crc32 instead of an adler32. 727 728 inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 729 memory, Z_STREAM_ERROR if a parameter is invalid (such as a null strm). msg 730 is set to null if there is no error message. inflateInit2 does not perform 731 any decompression apart from reading the zlib header if present: this will 732 be done by inflate(). (So next_in and avail_in may be modified, but next_out 733 and avail_out are unchanged.) 734 */ 735 736 ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm, 737 const Bytef *dictionary, 738 uInt dictLength)); 739 /* 740 Initializes the decompression dictionary from the given uncompressed byte 741 sequence. This function must be called immediately after a call of inflate, 742 if that call returned Z_NEED_DICT. The dictionary chosen by the compressor 743 can be determined from the adler32 value returned by that call of inflate. 744 The compressor and decompressor must use exactly the same dictionary (see 745 deflateSetDictionary). For raw inflate, this function can be called 746 immediately after inflateInit2() or inflateReset() and before any call of 747 inflate() to set the dictionary. The application must insure that the 748 dictionary that was used for compression is provided. 749 750 inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a 751 parameter is invalid (such as NULL dictionary) or the stream state is 752 inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the 753 expected one (incorrect adler32 value). inflateSetDictionary does not 754 perform any decompression: this will be done by subsequent calls of 755 inflate(). 756 */ 757 758 ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm)); 759 /* 760 Skips invalid compressed data until a full flush point (see above the 761 description of deflate with Z_FULL_FLUSH) can be found, or until all 762 available input is skipped. No output is provided. 763 764 inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR 765 if no more input was provided, Z_DATA_ERROR if no flush point has been found, 766 or Z_STREAM_ERROR if the stream structure was inconsistent. In the success 767 case, the application may save the current current value of total_in which 768 indicates where valid compressed data was found. In the error case, the 769 application may repeatedly call inflateSync, providing more input each time, 770 until success or end of the input data. 771 */ 772 773 ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest, 774 z_streamp source)); 775 /* 776 Sets the destination stream as a complete copy of the source stream. 777 778 This function can be useful when randomly accessing a large stream. The 779 first pass through the stream can periodically record the inflate state, 780 allowing restarting inflate at those points when randomly accessing the 781 stream. 782 783 inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not 784 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent 785 (such as zalloc being NULL). msg is left unchanged in both source and 786 destination. 787 */ 788 789 ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm)); 790 /* 791 This function is equivalent to inflateEnd followed by inflateInit, 792 but does not free and reallocate all the internal decompression state. 793 The stream will keep attributes that may have been set by inflateInit2. 794 795 inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source 796 stream state was inconsistent (such as zalloc or state being NULL). 797 */ 798 799 ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm, 800 int bits, 801 int value)); 802 /* 803 This function inserts bits in the inflate input stream. The intent is 804 that this function is used to start inflating at a bit position in the 805 middle of a byte. The provided bits will be used before any bytes are used 806 from next_in. This function should only be used with raw inflate, and 807 should be used before the first inflate() call after inflateInit2() or 808 inflateReset(). bits must be less than or equal to 16, and that many of the 809 least significant bits of value will be inserted in the input. 810 811 inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source 812 stream state was inconsistent. 813 */ 814 815 ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm, 816 gz_headerp head)); 817 /* 818 inflateGetHeader() requests that gzip header information be stored in the 819 provided gz_header structure. inflateGetHeader() may be called after 820 inflateInit2() or inflateReset(), and before the first call of inflate(). 821 As inflate() processes the gzip stream, head->done is zero until the header 822 is completed, at which time head->done is set to one. If a zlib stream is 823 being decoded, then head->done is set to -1 to indicate that there will be 824 no gzip header information forthcoming. Note that Z_BLOCK can be used to 825 force inflate() to return immediately after header processing is complete 826 and before any actual data is decompressed. 827 828 The text, time, xflags, and os fields are filled in with the gzip header 829 contents. hcrc is set to true if there is a header CRC. (The header CRC 830 was valid if done is set to one.) If extra is not Z_NULL, then extra_max 831 contains the maximum number of bytes to write to extra. Once done is true, 832 extra_len contains the actual extra field length, and extra contains the 833 extra field, or that field truncated if extra_max is less than extra_len. 834 If name is not Z_NULL, then up to name_max characters are written there, 835 terminated with a zero unless the length is greater than name_max. If 836 comment is not Z_NULL, then up to comm_max characters are written there, 837 terminated with a zero unless the length is greater than comm_max. When 838 any of extra, name, or comment are not Z_NULL and the respective field is 839 not present in the header, then that field is set to Z_NULL to signal its 840 absence. This allows the use of deflateSetHeader() with the returned 841 structure to duplicate the header. However if those fields are set to 842 allocated memory, then the application will need to save those pointers 843 elsewhere so that they can be eventually freed. 844 845 If inflateGetHeader is not used, then the header information is simply 846 discarded. The header is always checked for validity, including the header 847 CRC if present. inflateReset() will reset the process to discard the header 848 information. The application would need to call inflateGetHeader() again to 849 retrieve the header from the next gzip stream. 850 851 inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source 852 stream state was inconsistent. 853 */ 854 855 /* 856 ZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits, 857 unsigned char FAR *window)); 858 859 Initialize the internal stream state for decompression using inflateBack() 860 calls. The fields zalloc, zfree and opaque in strm must be initialized 861 before the call. If zalloc and zfree are Z_NULL, then the default library- 862 derived memory allocation routines are used. windowBits is the base two 863 logarithm of the window size, in the range 8..15. window is a caller 864 supplied buffer of that size. Except for special applications where it is 865 assured that deflate was used with small window sizes, windowBits must be 15 866 and a 32K byte window must be supplied to be able to decompress general 867 deflate streams. 868 869 See inflateBack() for the usage of these routines. 870 871 inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of 872 the paramaters are invalid, Z_MEM_ERROR if the internal state could not 873 be allocated, or Z_VERSION_ERROR if the version of the library does not 874 match the version of the header file. 875 */ 876 877 typedef unsigned (*in_func) OF((void FAR *, unsigned char FAR * FAR *)); 878 typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned)); 879 880 ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm, 881 in_func in, void FAR *in_desc, 882 out_func out, void FAR *out_desc)); 883 /* 884 inflateBack() does a raw inflate with a single call using a call-back 885 interface for input and output. This is more efficient than inflate() for 886 file i/o applications in that it avoids copying between the output and the 887 sliding window by simply making the window itself the output buffer. This 888 function trusts the application to not change the output buffer passed by 889 the output function, at least until inflateBack() returns. 890 891 inflateBackInit() must be called first to allocate the internal state 892 and to initialize the state with the user-provided window buffer. 893 inflateBack() may then be used multiple times to inflate a complete, raw 894 deflate stream with each call. inflateBackEnd() is then called to free 895 the allocated state. 896 897 A raw deflate stream is one with no zlib or gzip header or trailer. 898 This routine would normally be used in a utility that reads zip or gzip 899 files and writes out uncompressed files. The utility would decode the 900 header and process the trailer on its own, hence this routine expects 901 only the raw deflate stream to decompress. This is different from the 902 normal behavior of inflate(), which expects either a zlib or gzip header and 903 trailer around the deflate stream. 904 905 inflateBack() uses two subroutines supplied by the caller that are then 906 called by inflateBack() for input and output. inflateBack() calls those 907 routines until it reads a complete deflate stream and writes out all of the 908 uncompressed data, or until it encounters an error. The function's 909 parameters and return types are defined above in the in_func and out_func 910 typedefs. inflateBack() will call in(in_desc, &buf) which should return the 911 number of bytes of provided input, and a pointer to that input in buf. If 912 there is no input available, in() must return zero--buf is ignored in that 913 case--and inflateBack() will return a buffer error. inflateBack() will call 914 out(out_desc, buf, len) to write the uncompressed data buf[0..len-1]. out() 915 should return zero on success, or non-zero on failure. If out() returns 916 non-zero, inflateBack() will return with an error. Neither in() nor out() 917 are permitted to change the contents of the window provided to 918 inflateBackInit(), which is also the buffer that out() uses to write from. 919 The length written by out() will be at most the window size. Any non-zero 920 amount of input may be provided by in(). 921 922 For convenience, inflateBack() can be provided input on the first call by 923 setting strm->next_in and strm->avail_in. If that input is exhausted, then 924 in() will be called. Therefore strm->next_in must be initialized before 925 calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called 926 immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in 927 must also be initialized, and then if strm->avail_in is not zero, input will 928 initially be taken from strm->next_in[0 .. strm->avail_in - 1]. 929 930 The in_desc and out_desc parameters of inflateBack() is passed as the 931 first parameter of in() and out() respectively when they are called. These 932 descriptors can be optionally used to pass any information that the caller- 933 supplied in() and out() functions need to do their job. 934 935 On return, inflateBack() will set strm->next_in and strm->avail_in to 936 pass back any unused input that was provided by the last in() call. The 937 return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR 938 if in() or out() returned an error, Z_DATA_ERROR if there was a format 939 error in the deflate stream (in which case strm->msg is set to indicate the 940 nature of the error), or Z_STREAM_ERROR if the stream was not properly 941 initialized. In the case of Z_BUF_ERROR, an input or output error can be 942 distinguished using strm->next_in which will be Z_NULL only if in() returned 943 an error. If strm->next is not Z_NULL, then the Z_BUF_ERROR was due to 944 out() returning non-zero. (in() will always be called before out(), so 945 strm->next_in is assured to be defined if out() returns non-zero.) Note 946 that inflateBack() cannot return Z_OK. 947 */ 948 949 ZEXTERN int ZEXPORT inflateBackEnd OF((z_streamp strm)); 950 /* 951 All memory allocated by inflateBackInit() is freed. 952 953 inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream 954 state was inconsistent. 955 */ 956 957 ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void)); 958 /* Return flags indicating compile-time options. 959 960 Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other: 961 1.0: size of uInt 962 3.2: size of uLong 963 5.4: size of voidpf (pointer) 964 7.6: size of z_off_t 965 966 Compiler, assembler, and debug options: 967 8: DEBUG 968 9: ASMV or ASMINF -- use ASM code 969 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention 970 11: 0 (reserved) 971 972 One-time table building (smaller code, but not thread-safe if true): 973 12: BUILDFIXED -- build static block decoding tables when needed 974 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed 975 14,15: 0 (reserved) 976 977 Library content (indicates missing functionality): 978 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking 979 deflate code when not needed) 980 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect 981 and decode gzip streams (to avoid linking crc code) 982 18-19: 0 (reserved) 983 984 Operation variations (changes in library functionality): 985 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate 986 21: FASTEST -- deflate algorithm with only one, lowest compression level 987 22,23: 0 (reserved) 988 989 The sprintf variant used by gzprintf (zero is best): 990 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format 991 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure! 992 26: 0 = returns value, 1 = void -- 1 means inferred string length returned 993 994 Remainder: 995 27-31: 0 (reserved) 996 */ 997 998 999 /* utility functions */ 1000 1001 /* 1002 The following utility functions are implemented on top of the 1003 basic stream-oriented functions. To simplify the interface, some 1004 default options are assumed (compression level and memory usage, 1005 standard memory allocation functions). The source code of these 1006 utility functions can easily be modified if you need special options. 1007 */ 1008 1009 ZEXTERN int ZEXPORT compress OF((Bytef *dest, uLongf *destLen, 1010 const Bytef *source, uLong sourceLen)); 1011 /* 1012 Compresses the source buffer into the destination buffer. sourceLen is 1013 the byte length of the source buffer. Upon entry, destLen is the total 1014 size of the destination buffer, which must be at least the value returned 1015 by compressBound(sourceLen). Upon exit, destLen is the actual size of the 1016 compressed buffer. 1017 This function can be used to compress a whole file at once if the 1018 input file is mmap'ed. 1019 compress returns Z_OK if success, Z_MEM_ERROR if there was not 1020 enough memory, Z_BUF_ERROR if there was not enough room in the output 1021 buffer. 1022 */ 1023 1024 ZEXTERN int ZEXPORT compress2 OF((Bytef *dest, uLongf *destLen, 1025 const Bytef *source, uLong sourceLen, 1026 int level)); 1027 /* 1028 Compresses the source buffer into the destination buffer. The level 1029 parameter has the same meaning as in deflateInit. sourceLen is the byte 1030 length of the source buffer. Upon entry, destLen is the total size of the 1031 destination buffer, which must be at least the value returned by 1032 compressBound(sourceLen). Upon exit, destLen is the actual size of the 1033 compressed buffer. 1034 1035 compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 1036 memory, Z_BUF_ERROR if there was not enough room in the output buffer, 1037 Z_STREAM_ERROR if the level parameter is invalid. 1038 */ 1039 1040 ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen)); 1041 /* 1042 compressBound() returns an upper bound on the compressed size after 1043 compress() or compress2() on sourceLen bytes. It would be used before 1044 a compress() or compress2() call to allocate the destination buffer. 1045 */ 1046 1047 ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen, 1048 const Bytef *source, uLong sourceLen)); 1049 /* 1050 Decompresses the source buffer into the destination buffer. sourceLen is 1051 the byte length of the source buffer. Upon entry, destLen is the total 1052 size of the destination buffer, which must be large enough to hold the 1053 entire uncompressed data. (The size of the uncompressed data must have 1054 been saved previously by the compressor and transmitted to the decompressor 1055 by some mechanism outside the scope of this compression library.) 1056 Upon exit, destLen is the actual size of the compressed buffer. 1057 This function can be used to decompress a whole file at once if the 1058 input file is mmap'ed. 1059 1060 uncompress returns Z_OK if success, Z_MEM_ERROR if there was not 1061 enough memory, Z_BUF_ERROR if there was not enough room in the output 1062 buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete. 1063 */ 1064 1065 1066 typedef voidp gzFile; 1067 1068 ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode)); 1069 /* 1070 Opens a gzip (.gz) file for reading or writing. The mode parameter 1071 is as in fopen ("rb" or "wb") but can also include a compression level 1072 ("wb9") or a strategy: 'f' for filtered data as in "wb6f", 'h' for 1073 Huffman only compression as in "wb1h", or 'R' for run-length encoding 1074 as in "wb1R". (See the description of deflateInit2 for more information 1075 about the strategy parameter.) 1076 1077 gzopen can be used to read a file which is not in gzip format; in this 1078 case gzread will directly read from the file without decompression. 1079 1080 gzopen returns NULL if the file could not be opened or if there was 1081 insufficient memory to allocate the (de)compression state; errno 1082 can be checked to distinguish the two cases (if errno is zero, the 1083 zlib error is Z_MEM_ERROR). */ 1084 1085 long long gzgetMtime(gzFile file); 1086 /* Return modify time */ 1087 1088 ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode)); 1089 /* 1090 gzdopen() associates a gzFile with the file descriptor fd. File 1091 descriptors are obtained from calls like open, dup, creat, pipe or 1092 fileno (in the file has been previously opened with fopen). 1093 The mode parameter is as in gzopen. 1094 The next call of gzclose on the returned gzFile will also close the 1095 file descriptor fd, just like fclose(fdopen(fd), mode) closes the file 1096 descriptor fd. If you want to keep fd open, use gzdopen(dup(fd), mode). 1097 gzdopen returns NULL if there was insufficient memory to allocate 1098 the (de)compression state. 1099 */ 1100 1101 ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy)); 1102 /* 1103 Dynamically update the compression level or strategy. See the description 1104 of deflateInit2 for the meaning of these parameters. 1105 gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not 1106 opened for writing. 1107 */ 1108 1109 ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len)); 1110 /* 1111 Reads the given number of uncompressed bytes from the compressed file. 1112 If the input file was not in gzip format, gzread copies the given number 1113 of bytes into the buffer. 1114 gzread returns the number of uncompressed bytes actually read (0 for 1115 end of file, -1 for error). */ 1116 1117 ZEXTERN int ZEXPORT gzwrite OF((gzFile file, 1118 voidpc buf, unsigned len)); 1119 /* 1120 Writes the given number of uncompressed bytes into the compressed file. 1121 gzwrite returns the number of uncompressed bytes actually written 1122 (0 in case of error). 1123 */ 1124 1125 ZEXTERN int ZEXPORTVA gzprintf OF((gzFile file, const char *format, ...)); 1126 /* 1127 Converts, formats, and writes the args to the compressed file under 1128 control of the format string, as in fprintf. gzprintf returns the number of 1129 uncompressed bytes actually written (0 in case of error). The number of 1130 uncompressed bytes written is limited to 4095. The caller should assure that 1131 this limit is not exceeded. If it is exceeded, then gzprintf() will return 1132 return an error (0) with nothing written. In this case, there may also be a 1133 buffer overflow with unpredictable consequences, which is possible only if 1134 zlib was compiled with the insecure functions sprintf() or vsprintf() 1135 because the secure snprintf() or vsnprintf() functions were not available. 1136 */ 1137 1138 ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s)); 1139 /* 1140 Writes the given null-terminated string to the compressed file, excluding 1141 the terminating null character. 1142 gzputs returns the number of characters written, or -1 in case of error. 1143 */ 1144 1145 ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len)); 1146 /* 1147 Reads bytes from the compressed file until len-1 characters are read, or 1148 a newline character is read and transferred to buf, or an end-of-file 1149 condition is encountered. The string is then terminated with a null 1150 character. 1151 gzgets returns buf, or Z_NULL in case of error. 1152 */ 1153 1154 ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c)); 1155 /* 1156 Writes c, converted to an unsigned char, into the compressed file. 1157 gzputc returns the value that was written, or -1 in case of error. 1158 */ 1159 1160 ZEXTERN int ZEXPORT gzgetc OF((gzFile file)); 1161 /* 1162 Reads one byte from the compressed file. gzgetc returns this byte 1163 or -1 in case of end of file or error. 1164 */ 1165 1166 ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file)); 1167 /* 1168 Push one character back onto the stream to be read again later. 1169 Only one character of push-back is allowed. gzungetc() returns the 1170 character pushed, or -1 on failure. gzungetc() will fail if a 1171 character has been pushed but not read yet, or if c is -1. The pushed 1172 character will be discarded if the stream is repositioned with gzseek() 1173 or gzrewind(). 1174 */ 1175 1176 ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush)); 1177 /* 1178 Flushes all pending output into the compressed file. The parameter 1179 flush is as in the deflate() function. The return value is the zlib 1180 error number (see function gzerror below). gzflush returns Z_OK if 1181 the flush parameter is Z_FINISH and all output could be flushed. 1182 gzflush should be called only when strictly necessary because it can 1183 degrade compression. 1184 */ 1185 1186 ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file, 1187 z_off_t offset, int whence)); 1188 /* 1189 Sets the starting position for the next gzread or gzwrite on the 1190 given compressed file. The offset represents a number of bytes in the 1191 uncompressed data stream. The whence parameter is defined as in lseek(2); 1192 the value SEEK_END is not supported. 1193 If the file is opened for reading, this function is emulated but can be 1194 extremely slow. If the file is opened for writing, only forward seeks are 1195 supported; gzseek then compresses a sequence of zeroes up to the new 1196 starting position. 1197 1198 gzseek returns the resulting offset location as measured in bytes from 1199 the beginning of the uncompressed stream, or -1 in case of error, in 1200 particular if the file is opened for writing and the new starting position 1201 would be before the current position. 1202 */ 1203 1204 ZEXTERN int ZEXPORT gzrewind OF((gzFile file)); 1205 /* 1206 Rewinds the given file. This function is supported only for reading. 1207 1208 gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET) 1209 */ 1210 1211 ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file)); 1212 /* 1213 Returns the starting position for the next gzread or gzwrite on the 1214 given compressed file. This position represents a number of bytes in the 1215 uncompressed data stream. 1216 1217 gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR) 1218 */ 1219 1220 ZEXTERN int ZEXPORT gzeof OF((gzFile file)); 1221 /* 1222 Returns 1 when EOF has previously been detected reading the given 1223 input stream, otherwise zero. 1224 */ 1225 1226 ZEXTERN int ZEXPORT gzdirect OF((gzFile file)); 1227 /* 1228 Returns 1 if file is being read directly without decompression, otherwise 1229 zero. 1230 */ 1231 1232 ZEXTERN int ZEXPORT gzclose OF((gzFile file)); 1233 /* 1234 Flushes all pending output if necessary, closes the compressed file 1235 and deallocates all the (de)compression state. The return value is the zlib 1236 error number (see function gzerror below). 1237 */ 1238 1239 ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum)); 1240 /* 1241 Returns the error message for the last error which occurred on the 1242 given compressed file. errnum is set to zlib error number. If an 1243 error occurred in the file system and not in the compression library, 1244 errnum is set to Z_ERRNO and the application may consult errno 1245 to get the exact error code. 1246 */ 1247 1248 ZEXTERN void ZEXPORT gzclearerr OF((gzFile file)); 1249 /* 1250 Clears the error and end-of-file flags for file. This is analogous to the 1251 clearerr() function in stdio. This is useful for continuing to read a gzip 1252 file that is being written concurrently. 1253 */ 1254 1255 /* checksum functions */ 1256 1257 /* 1258 These functions are not related to compression but are exported 1259 anyway because they might be useful in applications using the 1260 compression library. 1261 */ 1262 1263 ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len)); 1264 /* 1265 Update a running Adler-32 checksum with the bytes buf[0..len-1] and 1266 return the updated checksum. If buf is NULL, this function returns 1267 the required initial value for the checksum. 1268 An Adler-32 checksum is almost as reliable as a CRC32 but can be computed 1269 much faster. Usage example: 1270 1271 uLong adler = adler32(0L, Z_NULL, 0); 1272 1273 while (read_buffer(buffer, length) != EOF) { 1274 adler = adler32(adler, buffer, length); 1275 } 1276 if (adler != original_adler) error(); 1277 */ 1278 1279 ZEXTERN void ZEXPORT adler32_range OF((uLong* min, uLong* max)); 1280 /* 1281 Set *min and *max (both of which must not be null) to the minimum and 1282 maximum possible checksum values that adler32 can produce. 1283 1284 This function is not part of original software distribution. It is 1285 added at Google (2003) in accordance with the copyright notice above, 1286 which permits alteration and redistribution of the original software 1287 provided, among other things, that altered source versions must be 1288 plainly marked as such and not misrepresented as being the original 1289 software. 1290 */ 1291 1292 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong adler1, uLong adler2, 1293 z_off_t len2)); 1294 /* 1295 Combine two Adler-32 checksums into one. For two sequences of bytes, seq1 1296 and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for 1297 each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of 1298 seq1 and seq2 concatenated, requiring only adler1, adler2, and len2. 1299 */ 1300 1301 ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len)); 1302 /* 1303 Update a running CRC-32 with the bytes buf[0..len-1] and return the 1304 updated CRC-32. If buf is NULL, this function returns the required initial 1305 value for the for the crc. Pre- and post-conditioning (one's complement) is 1306 performed within this function so it shouldn't be done by the application. 1307 Usage example: 1308 1309 uLong crc = crc32(0L, Z_NULL, 0); 1310 1311 while (read_buffer(buffer, length) != EOF) { 1312 crc = crc32(crc, buffer, length); 1313 } 1314 if (crc != original_crc) error(); 1315 */ 1316 1317 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2)); 1318 1319 /* 1320 Combine two CRC-32 check values into one. For two sequences of bytes, 1321 seq1 and seq2 with lengths len1 and len2, CRC-32 check values were 1322 calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32 1323 check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and 1324 len2. 1325 */ 1326 1327 1328 /* various hacks, don't look :) */ 1329 1330 /* deflateInit and inflateInit are macros to allow checking the zlib version 1331 * and the compiler's view of z_stream: 1332 */ 1333 ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level, 1334 const char *version, int stream_size)); 1335 ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm, 1336 const char *version, int stream_size)); 1337 ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method, 1338 int windowBits, int memLevel, 1339 int strategy, const char *version, 1340 int stream_size)); 1341 ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits, 1342 const char *version, int stream_size)); 1343 ZEXTERN int ZEXPORT inflateBackInit_ OF((z_streamp strm, int windowBits, 1344 unsigned char FAR *window, 1345 const char *version, 1346 int stream_size)); 1347 #define deflateInit(strm, level) \ 1348 deflateInit_((strm), (level), ZLIB_VERSION, sizeof(z_stream)) 1349 #define inflateInit(strm) \ 1350 inflateInit_((strm), ZLIB_VERSION, sizeof(z_stream)) 1351 #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \ 1352 deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\ 1353 (strategy), ZLIB_VERSION, sizeof(z_stream)) 1354 #define inflateInit2(strm, windowBits) \ 1355 inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream)) 1356 #define inflateBackInit(strm, windowBits, window) \ 1357 inflateBackInit_((strm), (windowBits), (window), \ 1358 ZLIB_VERSION, sizeof(z_stream)) 1359 1360 1361 #if !defined(ZUTIL_H) && !defined(NO_DUMMY_DECL) 1362 struct internal_state {int dummy;}; /* hack for buggy compilers */ 1363 #endif 1364 1365 ZEXTERN const char * ZEXPORT zError OF((int)); 1366 ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp z)); 1367 ZEXTERN const uLongf * ZEXPORT get_crc_table OF((void)); 1368 1369 #ifdef __cplusplus 1370 } 1371 #endif 1372 1373 #endif /* ZLIB_H */ 1374
