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#include "zconf.h" 35 36#ifdef __cplusplus 37extern "C" { 38#endif 39 40#define ZLIB_VERSION "1.2.3.1.Samba" 41#define ZLIB_VERNUM 0x1231 42/* 43 * Modified for Samba by Stefan Metzmacher <metze@samba.org> 2008 44 * 45 * inflateReset2() added and compiler warnings fixed 46 */ 47 48 49/* 50 The 'zlib' compression library provides in-memory compression and 51 decompression functions, including integrity checks of the uncompressed 52 data. This version of the library supports only one compression method 53 (deflation) but other algorithms will be added later and will have the same 54 stream interface. 55 56 Compression can be done in a single step if the buffers are large 57 enough (for example if an input file is mmap'ed), or can be done by 58 repeated calls of the compression function. In the latter case, the 59 application must provide more input and/or consume the output 60 (providing more output space) before each call. 61 62 The compressed data format used by default by the in-memory functions is 63 the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped 64 around a deflate stream, which is itself documented in RFC 1951. 65 66 The library also supports reading and writing files in gzip (.gz) format 67 with an interface similar to that of stdio using the functions that start 68 with "gz". The gzip format is different from the zlib format. gzip is a 69 gzip wrapper, documented in RFC 1952, wrapped around a deflate stream. 70 71 This library can optionally read and write gzip streams in memory as well. 72 73 The zlib format was designed to be compact and fast for use in memory 74 and on communications channels. The gzip format was designed for single- 75 file compression on file systems, has a larger header than zlib to maintain 76 directory information, and uses a different, slower check method than zlib. 77 78 The library does not install any signal handler. The decoder checks 79 the consistency of the compressed data, so the library should never 80 crash even in case of corrupted input. 81*/ 82 83typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size)); 84typedef void (*free_func) OF((voidpf opaque, voidpf address)); 85 86struct internal_state; 87 88typedef struct z_stream_s { 89 const Bytef *next_in; /* next input byte */ 90 uInt avail_in; /* number of bytes available at next_in */ 91 uLong total_in; /* total nb of input bytes read so far */ 92 93 Bytef *next_out; /* next output byte should be put there */ 94 uInt avail_out; /* remaining free space at next_out */ 95 uLong total_out; /* total nb of bytes output so far */ 96 97 const char *msg; /* last error message, NULL if no error */ 98 struct internal_state FAR *state; /* not visible by applications */ 99 100 alloc_func zalloc; /* used to allocate the internal state */ 101 free_func zfree; /* used to free the internal state */ 102 voidpf opaque; /* private data object passed to zalloc and zfree */ 103 104 int data_type; /* best guess about the data type: binary or text */ 105 uLong adler; /* adler32 value of the uncompressed data */ 106 uLong reserved; /* reserved for future use */ 107} z_stream; 108 109typedef z_stream FAR *z_streamp; 110 111/* 112 gzip header information passed to and from zlib routines. See RFC 1952 113 for more details on the meanings of these fields. 114*/ 115typedef struct gz_header_s { 116 int text; /* true if compressed data believed to be text */ 117 uLong time; /* modification time */ 118 int xflags; /* extra flags (not used when writing a gzip file) */ 119 int os; /* operating system */ 120 Bytef *extra; /* pointer to extra field or Z_NULL if none */ 121 uInt extra_len; /* extra field length (valid if extra != Z_NULL) */ 122 uInt extra_max; /* space at extra (only when reading header) */ 123 Bytef *name; /* pointer to zero-terminated file name or Z_NULL */ 124 uInt name_max; /* space at name (only when reading header) */ 125 Bytef *comment; /* pointer to zero-terminated comment or Z_NULL */ 126 uInt comm_max; /* space at comment (only when reading header) */ 127 int hcrc; /* true if there was or will be a header crc */ 128 int done; /* true when done reading gzip header (not used 129 when writing a gzip file) */ 130} gz_header; 131 132typedef gz_header FAR *gz_headerp; 133 134/* 135 The application must update next_in and avail_in when avail_in has 136 dropped to zero. It must update next_out and avail_out when avail_out 137 has dropped to zero. The application must initialize zalloc, zfree and 138 opaque before calling the init function. All other fields are set by the 139 compression library and must not be updated by the application. 140 141 The opaque value provided by the application will be passed as the first 142 parameter for calls of zalloc and zfree. This can be useful for custom 143 memory management. The compression library attaches no meaning to the 144 opaque value. 145 146 zalloc must return Z_NULL if there is not enough memory for the object. 147 If zlib is used in a multi-threaded application, zalloc and zfree must be 148 thread safe. 149 150 On 16-bit systems, the functions zalloc and zfree must be able to allocate 151 exactly 65536 bytes, but will not be required to allocate more than this 152 if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, 153 pointers returned by zalloc for objects of exactly 65536 bytes *must* 154 have their offset normalized to zero. The default allocation function 155 provided by this library ensures this (see zutil.c). To reduce memory 156 requirements and avoid any allocation of 64K objects, at the expense of 157 compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h). 158 159 The fields total_in and total_out can be used for statistics or 160 progress reports. After compression, total_in holds the total size of 161 the uncompressed data and may be saved for use in the decompressor 162 (particularly if the decompressor wants to decompress everything in 163 a single step). 164*/ 165 166 /* constants */ 167 168#define Z_NO_FLUSH 0 169#define Z_PARTIAL_FLUSH 1 /* will be removed, use Z_SYNC_FLUSH instead */ 170#define Z_SYNC_FLUSH 2 171#define Z_FULL_FLUSH 3 172#define Z_FINISH 4 173#define Z_BLOCK 5 174/* Allowed flush values; see deflate() and inflate() below for details */ 175 176#define Z_OK 0 177#define Z_STREAM_END 1 178#define Z_NEED_DICT 2 179#define Z_ERRNO (-1) 180#define Z_STREAM_ERROR (-2) 181#define Z_DATA_ERROR (-3) 182#define Z_MEM_ERROR (-4) 183#define Z_BUF_ERROR (-5) 184#define Z_VERSION_ERROR (-6) 185/* Return codes for the compression/decompression functions. Negative 186 * values are errors, positive values are used for special but normal events. 187 */ 188 189#define Z_NO_COMPRESSION 0 190#define Z_BEST_SPEED 1 191#define Z_BEST_COMPRESSION 9 192#define Z_DEFAULT_COMPRESSION (-1) 193/* compression levels */ 194 195#define Z_FILTERED 1 196#define Z_HUFFMAN_ONLY 2 197#define Z_RLE 3 198#define Z_FIXED 4 199#define Z_DEFAULT_STRATEGY 0 200/* compression strategy; see deflateInit2() below for details */ 201 202#define Z_BINARY 0 203#define Z_TEXT 1 204#define Z_ASCII Z_TEXT /* for compatibility with 1.2.2 and earlier */ 205#define Z_UNKNOWN 2 206/* Possible values of the data_type field (though see inflate()) */ 207 208#define Z_DEFLATED 8 209/* The deflate compression method (the only one supported in this version) */ 210 211#define Z_NULL 0 /* for initializing zalloc, zfree, opaque */ 212 213#define zlib_version zlibVersion() 214/* for compatibility with versions < 1.0.2 */ 215 216#if (__GNUC__ >= 3) && (__GNUC_MINOR__ >= 1) 217/** Use gcc attribute to check printf fns. a1 is the 1-based index of 218 * the parameter containing the format, and a2 the index of the first 219 * argument. Note that some gcc 2.x versions don't handle this 220 * properly **/ 221#define _Z_PRINTF_ATTRIBUTE(a1, a2) __attribute__ ((format (__printf__, a1, a2))) 222#else 223#define _Z_PRINTF_ATTRIBUTE(a1, a2) 224#endif 225 226 /* basic functions */ 227 228ZEXTERN const char * ZEXPORT zlibVersion OF((void)); 229/* The application can compare zlibVersion and ZLIB_VERSION for consistency. 230 If the first character differs, the library code actually used is 231 not compatible with the zlib.h header file used by the application. 232 This check is automatically made by deflateInit and inflateInit. 233 */ 234 235/* 236ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level)); 237 238 Initializes the internal stream state for compression. The fields 239 zalloc, zfree and opaque must be initialized before by the caller. 240 If zalloc and zfree are set to Z_NULL, deflateInit updates them to 241 use default allocation functions. 242 243 The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9: 244 1 gives best speed, 9 gives best compression, 0 gives no compression at 245 all (the input data is simply copied a block at a time). 246 Z_DEFAULT_COMPRESSION requests a default compromise between speed and 247 compression (currently equivalent to level 6). 248 249 deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not 250 enough memory, Z_STREAM_ERROR if level is not a valid compression level, 251 Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible 252 with the version assumed by the caller (ZLIB_VERSION). 253 msg is set to null if there is no error message. deflateInit does not 254 perform any compression: this will be done by deflate(). 255*/ 256 257 258ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush)); 259/* 260 deflate compresses as much data as possible, and stops when the input 261 buffer becomes empty or the output buffer becomes full. It may introduce some 262 output latency (reading input without producing any output) except when 263 forced to flush. 264 265 The detailed semantics are as follows. deflate performs one or both of the 266 following actions: 267 268 - Compress more input starting at next_in and update next_in and avail_in 269 accordingly. If not all input can be processed (because there is not 270 enough room in the output buffer), next_in and avail_in are updated and 271 processing will resume at this point for the next call of deflate(). 272 273 - Provide more output starting at next_out and update next_out and avail_out 274 accordingly. This action is forced if the parameter flush is non zero. 275 Forcing flush frequently degrades the compression ratio, so this parameter 276 should be set only when necessary (in interactive applications). 277 Some output may be provided even if flush is not set. 278 279 Before the call of deflate(), the application should ensure that at least 280 one of the actions is possible, by providing more input and/or consuming 281 more output, and updating avail_in or avail_out accordingly; avail_out 282 should never be zero before the call. The application can consume the 283 compressed output when it wants, for example when the output buffer is full 284 (avail_out == 0), or after each call of deflate(). If deflate returns Z_OK 285 and with zero avail_out, it must be called again after making room in the 286 output buffer because there might be more output pending. 287 288 Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to 289 decide how much data to accumualte before producing output, in order to 290 maximize compression. 291 292 If the parameter flush is set to Z_SYNC_FLUSH, all pending output is 293 flushed to the output buffer and the output is aligned on a byte boundary, so 294 that the decompressor can get all input data available so far. (In particular 295 avail_in is zero after the call if enough output space has been provided 296 before the call.) Flushing may degrade compression for some compression 297 algorithms and so it should be used only when necessary. 298 299 If flush is set to Z_FULL_FLUSH, all output is flushed as with 300 Z_SYNC_FLUSH, and the compression state is reset so that decompression can 301 restart from this point if previous compressed data has been damaged or if 302 random access is desired. Using Z_FULL_FLUSH too often can seriously degrade 303 compression. 304 305 If deflate returns with avail_out == 0, this function must be called again 306 with the same value of the flush parameter and more output space (updated 307 avail_out), until the flush is complete (deflate returns with non-zero 308 avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that 309 avail_out is greater than six to avoid repeated flush markers due to 310 avail_out == 0 on return. 311 312 If the parameter flush is set to Z_FINISH, pending input is processed, 313 pending output is flushed and deflate returns with Z_STREAM_END if there 314 was enough output space; if deflate returns with Z_OK, this function must be 315 called again with Z_FINISH and more output space (updated avail_out) but no 316 more input data, until it returns with Z_STREAM_END or an error. After 317 deflate has returned Z_STREAM_END, the only possible operations on the 318 stream are deflateReset or deflateEnd. 319 320 Z_FINISH can be used immediately after deflateInit if all the compression 321 is to be done in a single step. In this case, avail_out must be at least 322 the value returned by deflateBound (see below). If deflate does not return 323 Z_STREAM_END, then it must be called again as described above. 324 325 deflate() sets strm->adler to the adler32 checksum of all input read 326 so far (that is, total_in bytes). 327 328 deflate() may update strm->data_type if it can make a good guess about 329 the input data type (Z_BINARY or Z_TEXT). In doubt, the data is considered 330 binary. This field is only for information purposes and does not affect 331 the compression algorithm in any manner. 332 333 deflate() returns Z_OK if some progress has been made (more input 334 processed or more output produced), Z_STREAM_END if all input has been 335 consumed and all output has been produced (only when flush is set to 336 Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example 337 if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible 338 (for example avail_in or avail_out was zero). Note that Z_BUF_ERROR is not 339 fatal, and deflate() can be called again with more input and more output 340 space to continue compressing. 341*/ 342 343 344ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm)); 345/* 346 All dynamically allocated data structures for this stream are freed. 347 This function discards any unprocessed input and does not flush any 348 pending output. 349 350 deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the 351 stream state was inconsistent, Z_DATA_ERROR if the stream was freed 352 prematurely (some input or output was discarded). In the error case, 353 msg may be set but then points to a static string (which must not be 354 deallocated). 355*/ 356 357 358/* 359ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm)); 360 361 Initializes the internal stream state for decompression. The fields 362 next_in, avail_in, zalloc, zfree and opaque must be initialized before by 363 the caller. If next_in is not Z_NULL and avail_in is large enough (the exact 364 value depends on the compression method), inflateInit determines the 365 compression method from the zlib header and allocates all data structures 366 accordingly; otherwise the allocation will be deferred to the first call of 367 inflate. If zalloc and zfree are set to Z_NULL, inflateInit updates them to 368 use default allocation functions. 369 370 inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough 371 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the 372 version assumed by the caller. msg is set to null if there is no error 373 message. inflateInit does not perform any decompression apart from reading 374 the zlib header if present: this will be done by inflate(). (So next_in and 375 avail_in may be modified, but next_out and avail_out are unchanged.) 376*/ 377 378 379ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush)); 380/* 381 inflate decompresses as much data as possible, and stops when the input 382 buffer becomes empty or the output buffer becomes full. It may introduce 383 some output latency (reading input without producing any output) except when 384 forced to flush. 385 386 The detailed semantics are as follows. inflate performs one or both of the 387 following actions: 388 389 - Decompress more input starting at next_in and update next_in and avail_in 390 accordingly. If not all input can be processed (because there is not 391 enough room in the output buffer), next_in is updated and processing 392 will resume at this point for the next call of inflate(). 393 394 - Provide more output starting at next_out and update next_out and avail_out 395 accordingly. inflate() provides as much output as possible, until there 396 is no more input data or no more space in the output buffer (see below 397 about the flush parameter). 398 399 Before the call of inflate(), the application should ensure that at least 400 one of the actions is possible, by providing more input and/or consuming 401 more output, and updating the next_* and avail_* values accordingly. 402 The application can consume the uncompressed output when it wants, for 403 example when the output buffer is full (avail_out == 0), or after each 404 call of inflate(). If inflate returns Z_OK and with zero avail_out, it 405 must be called again after making room in the output buffer because there 406 might be more output pending. 407 408 The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, 409 Z_FINISH, or Z_BLOCK. Z_SYNC_FLUSH requests that inflate() flush as much 410 output as possible to the output buffer. Z_BLOCK requests that inflate() stop 411 if and when it gets to the next deflate block boundary. When decoding the 412 zlib or gzip format, this will cause inflate() to return immediately after 413 the header and before the first block. When doing a raw inflate, inflate() 414 will go ahead and process the first block, and will return when it gets to 415 the end of that block, or when it runs out of data. 416 417 The Z_BLOCK option assists in appending to or combining deflate streams. 418 Also to assist in this, on return inflate() will set strm->data_type to the 419 number of unused bits in the last byte taken from strm->next_in, plus 64 420 if inflate() is currently decoding the last block in the deflate stream, 421 plus 128 if inflate() returned immediately after decoding an end-of-block 422 code or decoding the complete header up to just before the first byte of the 423 deflate stream. The end-of-block will not be indicated until all of the 424 uncompressed data from that block has been written to strm->next_out. The 425 number of unused bits may in general be greater than seven, except when 426 bit 7 of data_type is set, in which case the number of unused bits will be 427 less than eight. 428 429 inflate() should normally be called until it returns Z_STREAM_END or an 430 error. However if all decompression is to be performed in a single step 431 (a single call of inflate), the parameter flush should be set to 432 Z_FINISH. In this case all pending input is processed and all pending 433 output is flushed; avail_out must be large enough to hold all the 434 uncompressed data. (The size of the uncompressed data may have been saved 435 by the compressor for this purpose.) The next operation on this stream must 436 be inflateEnd to deallocate the decompression state. The use of Z_FINISH 437 is never required, but can be used to inform inflate that a faster approach 438 may be used for the single inflate() call. 439 440 In this implementation, inflate() always flushes as much output as 441 possible to the output buffer, and always uses the faster approach on the 442 first call. So the only effect of the flush parameter in this implementation 443 is on the return value of inflate(), as noted below, or when it returns early 444 because Z_BLOCK is used. 445 446 If a preset dictionary is needed after this call (see inflateSetDictionary 447 below), inflate sets strm->adler to the adler32 checksum of the dictionary 448 chosen by the compressor and returns Z_NEED_DICT; otherwise it sets 449 strm->adler to the adler32 checksum of all output produced so far (that is, 450 total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described 451 below. At the end of the stream, inflate() checks that its computed adler32 452 checksum is equal to that saved by the compressor and returns Z_STREAM_END 453 only if the checksum is correct. 454 455 inflate() will decompress and check either zlib-wrapped or gzip-wrapped 456 deflate data. The header type is detected automatically. Any information 457 contained in the gzip header is not retained, so applications that need that 458 information should instead use raw inflate, see inflateInit2() below, or 459 inflateBack() and perform their own processing of the gzip header and 460 trailer. 461 462 inflate() returns Z_OK if some progress has been made (more input processed 463 or more output produced), Z_STREAM_END if the end of the compressed data has 464 been reached and all uncompressed output has been produced, Z_NEED_DICT if a 465 preset dictionary is needed at this point, Z_DATA_ERROR if the input data was 466 corrupted (input stream not conforming to the zlib format or incorrect check 467 value), Z_STREAM_ERROR if the stream structure was inconsistent (for example 468 if next_in or next_out was NULL), Z_MEM_ERROR if there was not enough memory, 469 Z_BUF_ERROR if no progress is possible or if there was not enough room in the 470 output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and 471 inflate() can be called again with more input and more output space to 472 continue decompressing. If Z_DATA_ERROR is returned, the application may then 473 call inflateSync() to look for a good compression block if a partial recovery 474 of the data is desired. 475*/ 476 477 478ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm)); 479/* 480 All dynamically allocated data structures for this stream are freed. 481 This function discards any unprocessed input and does not flush any 482 pending output. 483 484 inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state 485 was inconsistent. In the error case, msg may be set but then points to a 486 static string (which must not be deallocated). 487*/ 488 489 /* Advanced functions */ 490 491/* 492 The following functions are needed only in some special applications. 493*/ 494 495/* 496ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm, 497 int level, 498 int method, 499 int windowBits, 500 int memLevel, 501 int strategy)); 502 503 This is another version of deflateInit with more compression options. The 504 fields next_in, zalloc, zfree and opaque must be initialized before by 505 the caller. 506 507 The method parameter is the compression method. It must be Z_DEFLATED in 508 this version of the library. 509 510 The windowBits parameter is the base two logarithm of the window size 511 (the size of the history buffer). It should be in the range 8..15 for this 512 version of the library. Larger values of this parameter result in better 513 compression at the expense of memory usage. The default value is 15 if 514 deflateInit is used instead. 515 516 windowBits can also be -8..-15 for raw deflate. In this case, -windowBits 517 determines the window size. deflate() will then generate raw deflate data 518 with no zlib header or trailer, and will not compute an adler32 check value. 519 520 windowBits can also be greater than 15 for optional gzip encoding. Add 521 16 to windowBits to write a simple gzip header and trailer around the 522 compressed data instead of a zlib wrapper. The gzip header will have no 523 file name, no extra data, no comment, no modification time (set to zero), 524 no header crc, and the operating system will be set to 255 (unknown). If a 525 gzip stream is being written, strm->adler is a crc32 instead of an adler32. 526 527 The memLevel parameter specifies how much memory should be allocated 528 for the internal compression state. memLevel=1 uses minimum memory but 529 is slow and reduces compression ratio; memLevel=9 uses maximum memory 530 for optimal speed. The default value is 8. See zconf.h for total memory 531 usage as a function of windowBits and memLevel. 532 533 The strategy parameter is used to tune the compression algorithm. Use the 534 value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a 535 filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no 536 string match), or Z_RLE to limit match distances to one (run-length 537 encoding). Filtered data consists mostly of small values with a somewhat 538 random distribution. In this case, the compression algorithm is tuned to 539 compress them better. The effect of Z_FILTERED is to force more Huffman 540 coding and less string matching; it is somewhat intermediate between 541 Z_DEFAULT and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as fast as 542 Z_HUFFMAN_ONLY, but give better compression for PNG image data. The strategy 543 parameter only affects the compression ratio but not the correctness of the 544 compressed output even if it is not set appropriately. Z_FIXED prevents the 545 use of dynamic Huffman codes, allowing for a simpler decoder for special 546 applications. 547 548 deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 549 memory, Z_STREAM_ERROR if a parameter is invalid (such as an invalid 550 method). msg is set to null if there is no error message. deflateInit2 does 551 not perform any compression: this will be done by deflate(). 552*/ 553 554ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm, 555 const Bytef *dictionary, 556 uInt dictLength)); 557/* 558 Initializes the compression dictionary from the given byte sequence 559 without producing any compressed output. This function must be called 560 immediately after deflateInit, deflateInit2 or deflateReset, before any 561 call of deflate. The compressor and decompressor must use exactly the same 562 dictionary (see inflateSetDictionary). 563 564 The dictionary should consist of strings (byte sequences) that are likely 565 to be encountered later in the data to be compressed, with the most commonly 566 used strings preferably put towards the end of the dictionary. Using a 567 dictionary is most useful when the data to be compressed is short and can be 568 predicted with good accuracy; the data can then be compressed better than 569 with the default empty dictionary. 570 571 Depending on the size of the compression data structures selected by 572 deflateInit or deflateInit2, a part of the dictionary may in effect be 573 discarded, for example if the dictionary is larger than the window size in 574 deflate or deflate2. Thus the strings most likely to be useful should be 575 put at the end of the dictionary, not at the front. In addition, the 576 current implementation of deflate will use at most the window size minus 577 262 bytes of the provided dictionary. 578 579 Upon return of this function, strm->adler is set to the adler32 value 580 of the dictionary; the decompressor may later use this value to determine 581 which dictionary has been used by the compressor. (The adler32 value 582 applies to the whole dictionary even if only a subset of the dictionary is 583 actually used by the compressor.) If a raw deflate was requested, then the 584 adler32 value is not computed and strm->adler is not set. 585 586 deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a 587 parameter is invalid (such as NULL dictionary) or the stream state is 588 inconsistent (for example if deflate has already been called for this stream 589 or if the compression method is bsort). deflateSetDictionary does not 590 perform any compression: this will be done by deflate(). 591*/ 592 593ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest, 594 z_streamp source)); 595/* 596 Sets the destination stream as a complete copy of the source stream. 597 598 This function can be useful when several compression strategies will be 599 tried, for example when there are several ways of pre-processing the input 600 data with a filter. The streams that will be discarded should then be freed 601 by calling deflateEnd. Note that deflateCopy duplicates the internal 602 compression state which can be quite large, so this strategy is slow and 603 can consume lots of memory. 604 605 deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not 606 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent 607 (such as zalloc being NULL). msg is left unchanged in both source and 608 destination. 609*/ 610 611ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm)); 612/* 613 This function is equivalent to deflateEnd followed by deflateInit, 614 but does not free and reallocate all the internal compression state. 615 The stream will keep the same compression level and any other attributes 616 that may have been set by deflateInit2. 617 618 deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source 619 stream state was inconsistent (such as zalloc or state being NULL). 620*/ 621 622ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm, 623 int level, 624 int strategy)); 625/* 626 Dynamically update the compression level and compression strategy. The 627 interpretation of level and strategy is as in deflateInit2. This can be 628 used to switch between compression and straight copy of the input data, or 629 to switch to a different kind of input data requiring a different 630 strategy. If the compression level is changed, the input available so far 631 is compressed with the old level (and may be flushed); the new level will 632 take effect only at the next call of deflate(). 633 634 Before the call of deflateParams, the stream state must be set as for 635 a call of deflate(), since the currently available input may have to 636 be compressed and flushed. In particular, strm->avail_out must be non-zero. 637 638 deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source 639 stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR 640 if strm->avail_out was zero. 641*/ 642 643ZEXTERN int ZEXPORT deflateTune OF((z_streamp strm, 644 int good_length, 645 int max_lazy, 646 int nice_length, 647 int max_chain)); 648/* 649 Fine tune deflate's internal compression parameters. This should only be 650 used by someone who understands the algorithm used by zlib's deflate for 651 searching for the best matching string, and even then only by the most 652 fanatic optimizer trying to squeeze out the last compressed bit for their 653 specific input data. Read the deflate.c source code for the meaning of the 654 max_lazy, good_length, nice_length, and max_chain parameters. 655 656 deflateTune() can be called after deflateInit() or deflateInit2(), and 657 returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream. 658 */ 659 660ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm, 661 uLong sourceLen)); 662/* 663 deflateBound() returns an upper bound on the compressed size after 664 deflation of sourceLen bytes. It must be called after deflateInit() 665 or deflateInit2(). This would be used to allocate an output buffer 666 for deflation in a single pass, and so would be called before deflate(). 667*/ 668 669ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm, 670 int bits, 671 int value)); 672/* 673 deflatePrime() inserts bits in the deflate output stream. The intent 674 is that this function is used to start off the deflate output with the 675 bits leftover from a previous deflate stream when appending to it. As such, 676 this function can only be used for raw deflate, and must be used before the 677 first deflate() call after a deflateInit2() or deflateReset(). bits must be 678 less than or equal to 16, and that many of the least significant bits of 679 value will be inserted in the output. 680 681 deflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source 682 stream state was inconsistent. 683*/ 684 685ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm, 686 gz_headerp head)); 687/* 688 deflateSetHeader() provides gzip header information for when a gzip 689 stream is requested by deflateInit2(). deflateSetHeader() may be called 690 after deflateInit2() or deflateReset() and before the first call of 691 deflate(). The text, time, os, extra field, name, and comment information 692 in the provided gz_header structure are written to the gzip header (xflag is 693 ignored -- the extra flags are set according to the compression level). The 694 caller must assure that, if not Z_NULL, name and comment are terminated with 695 a zero byte, and that if extra is not Z_NULL, that extra_len bytes are 696 available there. If hcrc is true, a gzip header crc is included. Note that 697 the current versions of the command-line version of gzip (up through version 698 1.3.x) do not support header crc's, and will report that it is a "multi-part 699 gzip file" and give up. 700 701 If deflateSetHeader is not used, the default gzip header has text false, 702 the time set to zero, and os set to 255, with no extra, name, or comment 703 fields. The gzip header is returned to the default state by deflateReset(). 704 705 deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source 706 stream state was inconsistent. 707*/ 708 709/* 710ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm, 711 int windowBits)); 712 713 This is another version of inflateInit with an extra parameter. The 714 fields next_in, avail_in, zalloc, zfree and opaque must be initialized 715 before by the caller. 716 717 The windowBits parameter is the base two logarithm of the maximum window 718 size (the size of the history buffer). It should be in the range 8..15 for 719 this version of the library. The default value is 15 if inflateInit is used 720 instead. windowBits must be greater than or equal to the windowBits value 721 provided to deflateInit2() while compressing, or it must be equal to 15 if 722 deflateInit2() was not used. If a compressed stream with a larger window 723 size is given as input, inflate() will return with the error code 724 Z_DATA_ERROR instead of trying to allocate a larger window. 725 726 windowBits can also be -8..-15 for raw inflate. In this case, -windowBits 727 determines the window size. inflate() will then process raw deflate data, 728 not looking for a zlib or gzip header, not generating a check value, and not 729 looking for any check values for comparison at the end of the stream. This 730 is for use with other formats that use the deflate compressed data format 731 such as zip. Those formats provide their own check values. If a custom 732 format is developed using the raw deflate format for compressed data, it is 733 recommended that a check value such as an adler32 or a crc32 be applied to 734 the uncompressed data as is done in the zlib, gzip, and zip formats. For 735 most applications, the zlib format should be used as is. Note that comments 736 above on the use in deflateInit2() applies to the magnitude of windowBits. 737 738 windowBits can also be greater than 15 for optional gzip decoding. Add 739 32 to windowBits to enable zlib and gzip decoding with automatic header 740 detection, or add 16 to decode only the gzip format (the zlib format will 741 return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is 742 a crc32 instead of an adler32. 743 744 inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 745 memory, Z_STREAM_ERROR if a parameter is invalid (such as a null strm). msg 746 is set to null if there is no error message. inflateInit2 does not perform 747 any decompression apart from reading the zlib header if present: this will 748 be done by inflate(). (So next_in and avail_in may be modified, but next_out 749 and avail_out are unchanged.) 750*/ 751 752ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm, 753 const Bytef *dictionary, 754 uInt dictLength)); 755/* 756 Initializes the decompression dictionary from the given uncompressed byte 757 sequence. This function must be called immediately after a call of inflate, 758 if that call returned Z_NEED_DICT. The dictionary chosen by the compressor 759 can be determined from the adler32 value returned by that call of inflate. 760 The compressor and decompressor must use exactly the same dictionary (see 761 deflateSetDictionary). For raw inflate, this function can be called 762 immediately after inflateInit2() or inflateReset() and before any call of 763 inflate() to set the dictionary. The application must insure that the 764 dictionary that was used for compression is provided. 765 766 inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a 767 parameter is invalid (such as NULL dictionary) or the stream state is 768 inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the 769 expected one (incorrect adler32 value). inflateSetDictionary does not 770 perform any decompression: this will be done by subsequent calls of 771 inflate(). 772*/ 773 774ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm)); 775/* 776 Skips invalid compressed data until a full flush point (see above the 777 description of deflate with Z_FULL_FLUSH) can be found, or until all 778 available input is skipped. No output is provided. 779 780 inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR 781 if no more input was provided, Z_DATA_ERROR if no flush point has been found, 782 or Z_STREAM_ERROR if the stream structure was inconsistent. In the success 783 case, the application may save the current current value of total_in which 784 indicates where valid compressed data was found. In the error case, the 785 application may repeatedly call inflateSync, providing more input each time, 786 until success or end of the input data. 787*/ 788 789ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest, 790 z_streamp source)); 791/* 792 Sets the destination stream as a complete copy of the source stream. 793 794 This function can be useful when randomly accessing a large stream. The 795 first pass through the stream can periodically record the inflate state, 796 allowing restarting inflate at those points when randomly accessing the 797 stream. 798 799 inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not 800 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent 801 (such as zalloc being NULL). msg is left unchanged in both source and 802 destination. 803*/ 804 805ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm)); 806/* 807 This function is equivalent to inflateEnd followed by inflateInit, 808 but does not free and reallocate all the internal decompression state. 809 The stream will keep attributes that may have been set by inflateInit2. 810 811 inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source 812 stream state was inconsistent (such as zalloc or state being NULL). 813*/ 814 815ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm, 816 int bits, 817 int value)); 818/* 819 This function inserts bits in the inflate input stream. The intent is 820 that this function is used to start inflating at a bit position in the 821 middle of a byte. The provided bits will be used before any bytes are used 822 from next_in. This function should only be used with raw inflate, and 823 should be used before the first inflate() call after inflateInit2() or 824 inflateReset(). bits must be less than or equal to 16, and that many of the 825 least significant bits of value will be inserted in the input. 826 827 inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source 828 stream state was inconsistent. 829*/ 830 831ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm, 832 gz_headerp head)); 833/* 834 inflateGetHeader() requests that gzip header information be stored in the 835 provided gz_header structure. inflateGetHeader() may be called after 836 inflateInit2() or inflateReset(), and before the first call of inflate(). 837 As inflate() processes the gzip stream, head->done is zero until the header 838 is completed, at which time head->done is set to one. If a zlib stream is 839 being decoded, then head->done is set to -1 to indicate that there will be 840 no gzip header information forthcoming. Note that Z_BLOCK can be used to 841 force inflate() to return immediately after header processing is complete 842 and before any actual data is decompressed. 843 844 The text, time, xflags, and os fields are filled in with the gzip header 845 contents. hcrc is set to true if there is a header CRC. (The header CRC 846 was valid if done is set to one.) If extra is not Z_NULL, then extra_max 847 contains the maximum number of bytes to write to extra. Once done is true, 848 extra_len contains the actual extra field length, and extra contains the 849 extra field, or that field truncated if extra_max is less than extra_len. 850 If name is not Z_NULL, then up to name_max characters are written there, 851 terminated with a zero unless the length is greater than name_max. If 852 comment is not Z_NULL, then up to comm_max characters are written there, 853 terminated with a zero unless the length is greater than comm_max. When 854 any of extra, name, or comment are not Z_NULL and the respective field is 855 not present in the header, then that field is set to Z_NULL to signal its 856 absence. This allows the use of deflateSetHeader() with the returned 857 structure to duplicate the header. However if those fields are set to 858 allocated memory, then the application will need to save those pointers 859 elsewhere so that they can be eventually freed. 860 861 If inflateGetHeader is not used, then the header information is simply 862 discarded. The header is always checked for validity, including the header 863 CRC if present. inflateReset() will reset the process to discard the header 864 information. The application would need to call inflateGetHeader() again to 865 retrieve the header from the next gzip stream. 866 867 inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source 868 stream state was inconsistent. 869*/ 870 871/* 872ZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits, 873 unsigned char FAR *window)); 874 875 Initialize the internal stream state for decompression using inflateBack() 876 calls. The fields zalloc, zfree and opaque in strm must be initialized 877 before the call. If zalloc and zfree are Z_NULL, then the default library- 878 derived memory allocation routines are used. windowBits is the base two 879 logarithm of the window size, in the range 8..15. window is a caller 880 supplied buffer of that size. Except for special applications where it is 881 assured that deflate was used with small window sizes, windowBits must be 15 882 and a 32K byte window must be supplied to be able to decompress general 883 deflate streams. 884 885 See inflateBack() for the usage of these routines. 886 887 inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of 888 the paramaters are invalid, Z_MEM_ERROR if the internal state could not 889 be allocated, or Z_VERSION_ERROR if the version of the library does not 890 match the version of the header file. 891*/ 892 893typedef unsigned (*in_func) OF((void FAR *, unsigned const char FAR * FAR *)); 894typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned)); 895 896ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm, 897 in_func in, void FAR *in_desc, 898 out_func out, void FAR *out_desc)); 899/* 900 inflateBack() does a raw inflate with a single call using a call-back 901 interface for input and output. This is more efficient than inflate() for 902 file i/o applications in that it avoids copying between the output and the 903 sliding window by simply making the window itself the output buffer. This 904 function trusts the application to not change the output buffer passed by 905 the output function, at least until inflateBack() returns. 906 907 inflateBackInit() must be called first to allocate the internal state 908 and to initialize the state with the user-provided window buffer. 909 inflateBack() may then be used multiple times to inflate a complete, raw 910 deflate stream with each call. inflateBackEnd() is then called to free 911 the allocated state. 912 913 A raw deflate stream is one with no zlib or gzip header or trailer. 914 This routine would normally be used in a utility that reads zip or gzip 915 files and writes out uncompressed files. The utility would decode the 916 header and process the trailer on its own, hence this routine expects 917 only the raw deflate stream to decompress. This is different from the 918 normal behavior of inflate(), which expects either a zlib or gzip header and 919 trailer around the deflate stream. 920 921 inflateBack() uses two subroutines supplied by the caller that are then 922 called by inflateBack() for input and output. inflateBack() calls those 923 routines until it reads a complete deflate stream and writes out all of the 924 uncompressed data, or until it encounters an error. The function's 925 parameters and return types are defined above in the in_func and out_func 926 typedefs. inflateBack() will call in(in_desc, &buf) which should return the 927 number of bytes of provided input, and a pointer to that input in buf. If 928 there is no input available, in() must return zero--buf is ignored in that 929 case--and inflateBack() will return a buffer error. inflateBack() will call 930 out(out_desc, buf, len) to write the uncompressed data buf[0..len-1]. out() 931 should return zero on success, or non-zero on failure. If out() returns 932 non-zero, inflateBack() will return with an error. Neither in() nor out() 933 are permitted to change the contents of the window provided to 934 inflateBackInit(), which is also the buffer that out() uses to write from. 935 The length written by out() will be at most the window size. Any non-zero 936 amount of input may be provided by in(). 937 938 For convenience, inflateBack() can be provided input on the first call by 939 setting strm->next_in and strm->avail_in. If that input is exhausted, then 940 in() will be called. Therefore strm->next_in must be initialized before 941 calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called 942 immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in 943 must also be initialized, and then if strm->avail_in is not zero, input will 944 initially be taken from strm->next_in[0 .. strm->avail_in - 1]. 945 946 The in_desc and out_desc parameters of inflateBack() is passed as the 947 first parameter of in() and out() respectively when they are called. These 948 descriptors can be optionally used to pass any information that the caller- 949 supplied in() and out() functions need to do their job. 950 951 On return, inflateBack() will set strm->next_in and strm->avail_in to 952 pass back any unused input that was provided by the last in() call. The 953 return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR 954 if in() or out() returned an error, Z_DATA_ERROR if there was a format 955 error in the deflate stream (in which case strm->msg is set to indicate the 956 nature of the error), or Z_STREAM_ERROR if the stream was not properly 957 initialized. In the case of Z_BUF_ERROR, an input or output error can be 958 distinguished using strm->next_in which will be Z_NULL only if in() returned 959 an error. If strm->next is not Z_NULL, then the Z_BUF_ERROR was due to 960 out() returning non-zero. (in() will always be called before out(), so 961 strm->next_in is assured to be defined if out() returns non-zero.) Note 962 that inflateBack() cannot return Z_OK. 963*/ 964 965ZEXTERN int ZEXPORT inflateBackEnd OF((z_streamp strm)); 966/* 967 All memory allocated by inflateBackInit() is freed. 968 969 inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream 970 state was inconsistent. 971*/ 972 973ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void)); 974/* Return flags indicating compile-time options. 975 976 Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other: 977 1.0: size of uInt 978 3.2: size of uLong 979 5.4: size of voidpf (pointer) 980 7.6: size of z_off_t 981 982 Compiler, assembler, and debug options: 983 8: DEBUG 984 9: ASMV or ASMINF -- use ASM code 985 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention 986 11: 0 (reserved) 987 988 One-time table building (smaller code, but not thread-safe if true): 989 12: BUILDFIXED -- build static block decoding tables when needed 990 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed 991 14,15: 0 (reserved) 992 993 Library content (indicates missing functionality): 994 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking 995 deflate code when not needed) 996 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect 997 and decode gzip streams (to avoid linking crc code) 998 18-19: 0 (reserved) 999 1000 Operation variations (changes in library functionality): 1001 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate 1002 21: FASTEST -- deflate algorithm with only one, lowest compression level 1003 22,23: 0 (reserved) 1004 1005 The sprintf variant used by gzprintf (zero is best): 1006 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format 1007 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure! 1008 26: 0 = returns value, 1 = void -- 1 means inferred string length returned 1009 1010 Remainder: 1011 27-31: 0 (reserved) 1012 */ 1013 1014 1015 /* utility functions */ 1016 1017/* 1018 The following utility functions are implemented on top of the 1019 basic stream-oriented functions. To simplify the interface, some 1020 default options are assumed (compression level and memory usage, 1021 standard memory allocation functions). The source code of these 1022 utility functions can easily be modified if you need special options. 1023*/ 1024 1025ZEXTERN int ZEXPORT compress OF((Bytef *dest, uLongf *destLen, 1026 const Bytef *source, uLong sourceLen)); 1027/* 1028 Compresses the source buffer into the destination buffer. sourceLen is 1029 the byte length of the source buffer. Upon entry, destLen is the total 1030 size of the destination buffer, which must be at least the value returned 1031 by compressBound(sourceLen). Upon exit, destLen is the actual size of the 1032 compressed buffer. 1033 This function can be used to compress a whole file at once if the 1034 input file is mmap'ed. 1035 compress returns Z_OK if success, Z_MEM_ERROR if there was not 1036 enough memory, Z_BUF_ERROR if there was not enough room in the output 1037 buffer. 1038*/ 1039 1040ZEXTERN int ZEXPORT compress2 OF((Bytef *dest, uLongf *destLen, 1041 const Bytef *source, uLong sourceLen, 1042 int level)); 1043/* 1044 Compresses the source buffer into the destination buffer. The level 1045 parameter has the same meaning as in deflateInit. sourceLen is the byte 1046 length of the source buffer. Upon entry, destLen is the total size of the 1047 destination buffer, which must be at least the value returned by 1048 compressBound(sourceLen). Upon exit, destLen is the actual size of the 1049 compressed buffer. 1050 1051 compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 1052 memory, Z_BUF_ERROR if there was not enough room in the output buffer, 1053 Z_STREAM_ERROR if the level parameter is invalid. 1054*/ 1055 1056ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen)); 1057/* 1058 compressBound() returns an upper bound on the compressed size after 1059 compress() or compress2() on sourceLen bytes. It would be used before 1060 a compress() or compress2() call to allocate the destination buffer. 1061*/ 1062 1063ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen, 1064 const Bytef *source, uLong sourceLen)); 1065/* 1066 Decompresses the source buffer into the destination buffer. sourceLen is 1067 the byte length of the source buffer. Upon entry, destLen is the total 1068 size of the destination buffer, which must be large enough to hold the 1069 entire uncompressed data. (The size of the uncompressed data must have 1070 been saved previously by the compressor and transmitted to the decompressor 1071 by some mechanism outside the scope of this compression library.) 1072 Upon exit, destLen is the actual size of the compressed buffer. 1073 This function can be used to decompress a whole file at once if the 1074 input file is mmap'ed. 1075 1076 uncompress returns Z_OK if success, Z_MEM_ERROR if there was not 1077 enough memory, Z_BUF_ERROR if there was not enough room in the output 1078 buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete. 1079*/ 1080 1081 1082typedef voidp gzFile; 1083 1084ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode)); 1085/* 1086 Opens a gzip (.gz) file for reading or writing. The mode parameter 1087 is as in fopen ("rb" or "wb") but can also include a compression level 1088 ("wb9") or a strategy: 'f' for filtered data as in "wb6f", 'h' for 1089 Huffman only compression as in "wb1h", or 'R' for run-length encoding 1090 as in "wb1R". (See the description of deflateInit2 for more information 1091 about the strategy parameter.) 1092 1093 gzopen can be used to read a file which is not in gzip format; in this 1094 case gzread will directly read from the file without decompression. 1095 1096 gzopen returns NULL if the file could not be opened or if there was 1097 insufficient memory to allocate the (de)compression state; errno 1098 can be checked to distinguish the two cases (if errno is zero, the 1099 zlib error is Z_MEM_ERROR). */ 1100 1101ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode)); 1102/* 1103 gzdopen() associates a gzFile with the file descriptor fd. File 1104 descriptors are obtained from calls like open, dup, creat, pipe or 1105 fileno (in the file has been previously opened with fopen). 1106 The mode parameter is as in gzopen. 1107 The next call of gzclose on the returned gzFile will also close the 1108 file descriptor fd, just like fclose(fdopen(fd), mode) closes the file 1109 descriptor fd. If you want to keep fd open, use gzdopen(dup(fd), mode). 1110 gzdopen returns NULL if there was insufficient memory to allocate 1111 the (de)compression state. 1112*/ 1113 1114ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy)); 1115/* 1116 Dynamically update the compression level or strategy. See the description 1117 of deflateInit2 for the meaning of these parameters. 1118 gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not 1119 opened for writing. 1120*/ 1121 1122ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len)); 1123/* 1124 Reads the given number of uncompressed bytes from the compressed file. 1125 If the input file was not in gzip format, gzread copies the given number 1126 of bytes into the buffer. 1127 gzread returns the number of uncompressed bytes actually read (0 for 1128 end of file, -1 for error). */ 1129 1130ZEXTERN int ZEXPORT gzwrite OF((gzFile file, 1131 voidpc buf, unsigned len)); 1132/* 1133 Writes the given number of uncompressed bytes into the compressed file. 1134 gzwrite returns the number of uncompressed bytes actually written 1135 (0 in case of error). 1136*/ 1137 1138ZEXTERN int ZEXPORTVA gzprintf OF((gzFile file, const char *format, ...)) 1139 _Z_PRINTF_ATTRIBUTE(2, 3); 1140/* 1141 Converts, formats, and writes the args to the compressed file under 1142 control of the format string, as in fprintf. gzprintf returns the number of 1143 uncompressed bytes actually written (0 in case of error). The number of 1144 uncompressed bytes written is limited to 4095. The caller should assure that 1145 this limit is not exceeded. If it is exceeded, then gzprintf() will return 1146 return an error (0) with nothing written. In this case, there may also be a 1147 buffer overflow with unpredictable consequences, which is possible only if 1148 zlib was compiled with the insecure functions sprintf() or vsprintf() 1149 because the secure snprintf() or vsnprintf() functions were not available. 1150*/ 1151 1152ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s)); 1153/* 1154 Writes the given null-terminated string to the compressed file, excluding 1155 the terminating null character. 1156 gzputs returns the number of characters written, or -1 in case of error. 1157*/ 1158 1159ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len)); 1160/* 1161 Reads bytes from the compressed file until len-1 characters are read, or 1162 a newline character is read and transferred to buf, or an end-of-file 1163 condition is encountered. The string is then terminated with a null 1164 character. 1165 gzgets returns buf, or Z_NULL in case of error. 1166*/ 1167 1168ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c)); 1169/* 1170 Writes c, converted to an unsigned char, into the compressed file. 1171 gzputc returns the value that was written, or -1 in case of error. 1172*/ 1173 1174ZEXTERN int ZEXPORT gzgetc OF((gzFile file)); 1175/* 1176 Reads one byte from the compressed file. gzgetc returns this byte 1177 or -1 in case of end of file or error. 1178*/ 1179 1180ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file)); 1181/* 1182 Push one character back onto the stream to be read again later. 1183 Only one character of push-back is allowed. gzungetc() returns the 1184 character pushed, or -1 on failure. gzungetc() will fail if a 1185 character has been pushed but not read yet, or if c is -1. The pushed 1186 character will be discarded if the stream is repositioned with gzseek() 1187 or gzrewind(). 1188*/ 1189 1190ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush)); 1191/* 1192 Flushes all pending output into the compressed file. The parameter 1193 flush is as in the deflate() function. The return value is the zlib 1194 error number (see function gzerror below). gzflush returns Z_OK if 1195 the flush parameter is Z_FINISH and all output could be flushed. 1196 gzflush should be called only when strictly necessary because it can 1197 degrade compression. 1198*/ 1199 1200ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file, 1201 z_off_t offset, int whence)); 1202/* 1203 Sets the starting position for the next gzread or gzwrite on the 1204 given compressed file. The offset represents a number of bytes in the 1205 uncompressed data stream. The whence parameter is defined as in lseek(2); 1206 the value SEEK_END is not supported. 1207 If the file is opened for reading, this function is emulated but can be 1208 extremely slow. If the file is opened for writing, only forward seeks are 1209 supported; gzseek then compresses a sequence of zeroes up to the new 1210 starting position. 1211 1212 gzseek returns the resulting offset location as measured in bytes from 1213 the beginning of the uncompressed stream, or -1 in case of error, in 1214 particular if the file is opened for writing and the new starting position 1215 would be before the current position. 1216*/ 1217 1218ZEXTERN int ZEXPORT gzrewind OF((gzFile file)); 1219/* 1220 Rewinds the given file. This function is supported only for reading. 1221 1222 gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET) 1223*/ 1224 1225ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file)); 1226/* 1227 Returns the starting position for the next gzread or gzwrite on the 1228 given compressed file. This position represents a number of bytes in the 1229 uncompressed data stream. 1230 1231 gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR) 1232*/ 1233 1234ZEXTERN int ZEXPORT gzeof OF((gzFile file)); 1235/* 1236 Returns 1 when EOF has previously been detected reading the given 1237 input stream, otherwise zero. 1238*/ 1239 1240ZEXTERN int ZEXPORT gzdirect OF((gzFile file)); 1241/* 1242 Returns 1 if file is being read directly without decompression, otherwise 1243 zero. 1244*/ 1245 1246ZEXTERN int ZEXPORT gzclose OF((gzFile file)); 1247/* 1248 Flushes all pending output if necessary, closes the compressed file 1249 and deallocates all the (de)compression state. The return value is the zlib 1250 error number (see function gzerror below). 1251*/ 1252 1253ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum)); 1254/* 1255 Returns the error message for the last error which occurred on the 1256 given compressed file. errnum is set to zlib error number. If an 1257 error occurred in the file system and not in the compression library, 1258 errnum is set to Z_ERRNO and the application may consult errno 1259 to get the exact error code. 1260*/ 1261 1262ZEXTERN void ZEXPORT gzclearerr OF((gzFile file)); 1263/* 1264 Clears the error and end-of-file flags for file. This is analogous to the 1265 clearerr() function in stdio. This is useful for continuing to read a gzip 1266 file that is being written concurrently. 1267*/ 1268 1269 /* checksum functions */ 1270 1271/* 1272 These functions are not related to compression but are exported 1273 anyway because they might be useful in applications using the 1274 compression library. 1275*/ 1276 1277ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len)); 1278/* 1279 Update a running Adler-32 checksum with the bytes buf[0..len-1] and 1280 return the updated checksum. If buf is NULL, this function returns 1281 the required initial value for the checksum. 1282 An Adler-32 checksum is almost as reliable as a CRC32 but can be computed 1283 much faster. Usage example: 1284 1285 uLong adler = adler32(0L, Z_NULL, 0); 1286 1287 while (read_buffer(buffer, length) != EOF) { 1288 adler = adler32(adler, buffer, length); 1289 } 1290 if (adler != original_adler) error(); 1291*/ 1292 1293ZEXTERN uLong ZEXPORT adler32_combine OF((uLong adler1, uLong adler2, 1294 z_off_t len2)); 1295/* 1296 Combine two Adler-32 checksums into one. For two sequences of bytes, seq1 1297 and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for 1298 each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of 1299 seq1 and seq2 concatenated, requiring only adler1, adler2, and len2. 1300*/ 1301 1302ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len)); 1303/* 1304 Update a running CRC-32 with the bytes buf[0..len-1] and return the 1305 updated CRC-32. If buf is NULL, this function returns the required initial 1306 value for the for the crc. Pre- and post-conditioning (one's complement) is 1307 performed within this function so it shouldn't be done by the application. 1308 Usage example: 1309 1310 uLong crc = crc32(0L, Z_NULL, 0); 1311 1312 while (read_buffer(buffer, length) != EOF) { 1313 crc = crc32(crc, buffer, length); 1314 } 1315 if (crc != original_crc) error(); 1316*/ 1317 1318ZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2)); 1319 1320/* 1321 Combine two CRC-32 check values into one. For two sequences of bytes, 1322 seq1 and seq2 with lengths len1 and len2, CRC-32 check values were 1323 calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32 1324 check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and 1325 len2. 1326*/ 1327 1328 1329 /* various hacks, don't look :) */ 1330 1331/* deflateInit and inflateInit are macros to allow checking the zlib version 1332 * and the compiler's view of z_stream: 1333 */ 1334ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level, 1335 const char *version, int stream_size)); 1336ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm, 1337 const char *version, int stream_size)); 1338ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method, 1339 int windowBits, int memLevel, 1340 int strategy, const char *version, 1341 int stream_size)); 1342ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits, 1343 const char *version, int stream_size)); 1344ZEXTERN int ZEXPORT inflateBackInit_ OF((z_streamp strm, int windowBits, 1345 unsigned char FAR *window, 1346 const char *version, 1347 int stream_size)); 1348#define deflateInit(strm, level) \ 1349 deflateInit_((strm), (level), ZLIB_VERSION, sizeof(z_stream)) 1350#define inflateInit(strm) \ 1351 inflateInit_((strm), ZLIB_VERSION, sizeof(z_stream)) 1352#define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \ 1353 deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\ 1354 (strategy), ZLIB_VERSION, sizeof(z_stream)) 1355#define inflateInit2(strm, windowBits) \ 1356 inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream)) 1357#define inflateBackInit(strm, windowBits, window) \ 1358 inflateBackInit_((strm), (windowBits), (window), \ 1359 ZLIB_VERSION, sizeof(z_stream)) 1360 1361 1362#if !defined(ZUTIL_H) && !defined(NO_DUMMY_DECL) 1363 struct internal_state {int dummy;}; /* hack for buggy compilers */ 1364#endif 1365 1366ZEXTERN const char * ZEXPORT zError OF((int)); 1367ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp z)); 1368ZEXTERN const uLongf * ZEXPORT get_crc_table OF((void)); 1369 1370#ifdef __cplusplus 1371} 1372#endif 1373 1374#endif /* ZLIB_H */ 1375