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