1 /* zlib.h -- interface of the 'zlib' general purpose compression library 2 version 1.2.2.2, December 30th, 2004 3 4 Copyright (C) 1995-2004 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 37 extern "C" { 38 #endif 39 40 #define ZLIB_VERSION "1.2.2.f-rsyncable" 41 #define ZLIB_VERNUM 0x122f 42 43 /* 44 The 'zlib' compression library provides in-memory compression and 45 decompression functions, including integrity checks of the uncompressed 46 data. This version of the library supports only one compression method 47 (deflation) but other algorithms will be added later and will have the same 48 stream interface. 49 50 Compression can be done in a single step if the buffers are large 51 enough (for example if an input file is mmap'ed), or can be done by 52 repeated calls of the compression function. In the latter case, the 53 application must provide more input and/or consume the output 54 (providing more output space) before each call. 55 56 The compressed data format used by default by the in-memory functions is 57 the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped 58 around a deflate stream, which is itself documented in RFC 1951. 59 60 The library also supports reading and writing files in gzip (.gz) format 61 with an interface similar to that of stdio using the functions that start 62 with "gz". The gzip format is different from the zlib format. gzip is a 63 gzip wrapper, documented in RFC 1952, wrapped around a deflate stream. 64 65 This library can optionally read and write gzip streams in memory as well. 66 67 The zlib format was designed to be compact and fast for use in memory 68 and on communications channels. The gzip format was designed for single- 69 file compression on file systems, has a larger header than zlib to maintain 70 directory information, and uses a different, slower check method than zlib. 71 72 The library does not install any signal handler. The decoder checks 73 the consistency of the compressed data, so the library should never 74 crash even in case of corrupted input. 75 */ 76 77 typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size)); 78 typedef void (*free_func) OF((voidpf opaque, voidpf address)); 79 80 struct internal_state; 81 82 typedef struct z_stream_s { 83 Bytef *next_in; /* next input byte */ 84 uInt avail_in; /* number of bytes available at next_in */ 85 uLong total_in; /* total nb of input bytes read so far */ 86 87 Bytef *next_out; /* next output byte should be put there */ 88 uInt avail_out; /* remaining free space at next_out */ 89 uLong total_out; /* total nb of bytes output so far */ 90 91 char *msg; /* last error message, NULL if no error */ 92 struct internal_state FAR *state; /* not visible by applications */ 93 94 alloc_func zalloc; /* used to allocate the internal state */ 95 free_func zfree; /* used to free the internal state */ 96 voidpf opaque; /* private data object passed to zalloc and zfree */ 97 98 int data_type; /* best guess about the data type: binary or text */ 99 uLong adler; /* adler32 value of the uncompressed data */ 100 uLong reserved; /* reserved for future use */ 101 } z_stream; 102 103 typedef z_stream FAR *z_streamp; 104 105 /* 106 gzip header information passed to and from zlib routines. See RFC 1952 107 for more details on the meanings of these fields. 108 */ 109 typedef struct gz_header_s { 110 int text; /* true if compressed data believed to be text */ 111 uLong time; /* modification time */ 112 int xflags; /* extra flags (not used when writing a gzip file) */ 113 int os; /* operating system */ 114 Bytef *extra; /* pointer to extra field or Z_NULL if none */ 115 uInt extra_len; /* extra field length (valid if extra != Z_NULL) */ 116 uInt extra_max; /* space at extra (only when reading header) */ 117 Bytef *name; /* pointer to zero-terminated file name or Z_NULL */ 118 uInt name_max; /* space at name (only when reading header) */ 119 Bytef *comment; /* pointer to zero-terminated comment or Z_NULL */ 120 uInt comm_max; /* space at comment (only when reading header) */ 121 int hcrc; /* true if there was or will be a header crc */ 122 int done; /* true when done reading gzip header (not used 123 when writing a gzip file) */ 124 } gz_header; 125 126 typedef gz_header FAR *gz_headerp; 127 128 /* 129 The application must update next_in and avail_in when avail_in has 130 dropped to zero. It must update next_out and avail_out when avail_out 131 has dropped to zero. The application must initialize zalloc, zfree and 132 opaque before calling the init function. All other fields are set by the 133 compression library and must not be updated by the application. 134 135 The opaque value provided by the application will be passed as the first 136 parameter for calls of zalloc and zfree. This can be useful for custom 137 memory management. The compression library attaches no meaning to the 138 opaque value. 139 140 zalloc must return Z_NULL if there is not enough memory for the object. 141 If zlib is used in a multi-threaded application, zalloc and zfree must be 142 thread safe. 143 144 On 16-bit systems, the functions zalloc and zfree must be able to allocate 145 exactly 65536 bytes, but will not be required to allocate more than this 146 if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, 147 pointers returned by zalloc for objects of exactly 65536 bytes *must* 148 have their offset normalized to zero. The default allocation function 149 provided by this library ensures this (see zutil.c). To reduce memory 150 requirements and avoid any allocation of 64K objects, at the expense of 151 compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h). 152 153 The fields total_in and total_out can be used for statistics or 154 progress reports. After compression, total_in holds the total size of 155 the uncompressed data and may be saved for use in the decompressor 156 (particularly if the decompressor wants to decompress everything in 157 a single step). 158 */ 159 160 /* constants */ 161 162 #define Z_NO_FLUSH 0 163 #define Z_PARTIAL_FLUSH 1 /* will be removed, use Z_SYNC_FLUSH instead */ 164 #define Z_SYNC_FLUSH 2 165 #define Z_FULL_FLUSH 3 166 #define Z_FINISH 4 167 #define Z_BLOCK 5 168 /* Allowed flush values; see deflate() and inflate() below for details */ 169 170 #define Z_OK 0 171 #define Z_STREAM_END 1 172 #define Z_NEED_DICT 2 173 #define Z_ERRNO (-1) 174 #define Z_STREAM_ERROR (-2) 175 #define Z_DATA_ERROR (-3) 176 #define Z_MEM_ERROR (-4) 177 #define Z_BUF_ERROR (-5) 178 #define Z_VERSION_ERROR (-6) 179 /* Return codes for the compression/decompression functions. Negative 180 * values are errors, positive values are used for special but normal events. 181 */ 182 183 #define Z_NO_COMPRESSION 0 184 #define Z_BEST_SPEED 1 185 #define Z_BEST_COMPRESSION 9 186 #define Z_DEFAULT_COMPRESSION (-1) 187 /* compression levels */ 188 189 #define Z_FILTERED 1 190 #define Z_HUFFMAN_ONLY 2 191 #define Z_RLE 3 192 #define Z_FIXED 4 193 #define Z_DEFAULT_STRATEGY 0 194 #define Z_RSYNCABLE 0x4000 195 /* compression strategy; see deflateInit2() below for details */ 196 197 #define Z_BINARY 0 198 #define Z_TEXT 1 199 #define Z_ASCII Z_TEXT /* for compatibility with 1.2.2 and earlier */ 200 #define Z_UNKNOWN 2 201 /* Possible values of the data_type field (though see inflate()) */ 202 203 #define Z_DEFLATED 8 204 /* The deflate compression method (the only one supported in this version) */ 205 206 #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */ 207 208 #define zlib_version zlibVersion() 209 /* for compatibility with versions < 1.0.2 */ 210 211 /* basic functions */ 212 213 ZEXTERN const char * ZEXPORT zlibVersion OF((void)); 214 /* The application can compare zlibVersion and ZLIB_VERSION for consistency. 215 If the first character differs, the library code actually used is 216 not compatible with the zlib.h header file used by the application. 217 This check is automatically made by deflateInit and inflateInit. 218 */ 219 220 /* 221 ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level)); 222 223 Initializes the internal stream state for compression. The fields 224 zalloc, zfree and opaque must be initialized before by the caller. 225 If zalloc and zfree are set to Z_NULL, deflateInit updates them to 226 use default allocation functions. 227 228 The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9: 229 1 gives best speed, 9 gives best compression, 0 gives no compression at 230 all (the input data is simply copied a block at a time). 231 Z_DEFAULT_COMPRESSION requests a default compromise between speed and 232 compression (currently equivalent to level 6). 233 234 deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not 235 enough memory, Z_STREAM_ERROR if level is not a valid compression level, 236 Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible 237 with the version assumed by the caller (ZLIB_VERSION). 238 msg is set to null if there is no error message. deflateInit does not 239 perform any compression: this will be done by deflate(). 240 */ 241 242 243 ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush)); 244 /* 245 deflate compresses as much data as possible, and stops when the input 246 buffer becomes empty or the output buffer becomes full. It may introduce some 247 output latency (reading input without producing any output) except when 248 forced to flush. 249 250 The detailed semantics are as follows. deflate performs one or both of the 251 following actions: 252 253 - Compress more input starting at next_in and update next_in and avail_in 254 accordingly. If not all input can be processed (because there is not 255 enough room in the output buffer), next_in and avail_in are updated and 256 processing will resume at this point for the next call of deflate(). 257 258 - Provide more output starting at next_out and update next_out and avail_out 259 accordingly. This action is forced if the parameter flush is non zero. 260 Forcing flush frequently degrades the compression ratio, so this parameter 261 should be set only when necessary (in interactive applications). 262 Some output may be provided even if flush is not set. 263 264 Before the call of deflate(), the application should ensure that at least 265 one of the actions is possible, by providing more input and/or consuming 266 more output, and updating avail_in or avail_out accordingly; avail_out 267 should never be zero before the call. The application can consume the 268 compressed output when it wants, for example when the output buffer is full 269 (avail_out == 0), or after each call of deflate(). If deflate returns Z_OK 270 and with zero avail_out, it must be called again after making room in the 271 output buffer because there might be more output pending. 272 273 Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to 274 decide how much data to accumualte before producing output, in order to 275 maximize compression. 276 277 If the parameter flush is set to Z_SYNC_FLUSH, all pending output is 278 flushed to the output buffer and the output is aligned on a byte boundary, so 279 that the decompressor can get all input data available so far. (In particular 280 avail_in is zero after the call if enough output space has been provided 281 before the call.) Flushing may degrade compression for some compression 282 algorithms and so it should be used only when necessary. 283 284 If flush is set to Z_FULL_FLUSH, all output is flushed as with 285 Z_SYNC_FLUSH, and the compression state is reset so that decompression can 286 restart from this point if previous compressed data has been damaged or if 287 random access is desired. Using Z_FULL_FLUSH too often can seriously degrade 288 compression. 289 290 If deflate returns with avail_out == 0, this function must be called again 291 with the same value of the flush parameter and more output space (updated 292 avail_out), until the flush is complete (deflate returns with non-zero 293 avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that 294 avail_out is greater than six to avoid repeated flush markers due to 295 avail_out == 0 on return. 296 297 If the parameter flush is set to Z_FINISH, pending input is processed, 298 pending output is flushed and deflate returns with Z_STREAM_END if there 299 was enough output space; if deflate returns with Z_OK, this function must be 300 called again with Z_FINISH and more output space (updated avail_out) but no 301 more input data, until it returns with Z_STREAM_END or an error. After 302 deflate has returned Z_STREAM_END, the only possible operations on the 303 stream are deflateReset or deflateEnd. 304 305 Z_FINISH can be used immediately after deflateInit if all the compression 306 is to be done in a single step. In this case, avail_out must be at least 307 the value returned by deflateBound (see below). If deflate does not return 308 Z_STREAM_END, then it must be called again as described above. 309 310 deflate() sets strm->adler to the adler32 checksum of all input read 311 so far (that is, total_in bytes). 312 313 deflate() may update strm->data_type if it can make a good guess about 314 the input data type (Z_BINARY or Z_TEXT). In doubt, the data is considered 315 binary. This field is only for information purposes and does not affect 316 the compression algorithm in any manner. 317 318 deflate() returns Z_OK if some progress has been made (more input 319 processed or more output produced), Z_STREAM_END if all input has been 320 consumed and all output has been produced (only when flush is set to 321 Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example 322 if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible 323 (for example avail_in or avail_out was zero). Note that Z_BUF_ERROR is not 324 fatal, and deflate() can be called again with more input and more output 325 space to continue compressing. 326 */ 327 328 329 ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm)); 330 /* 331 All dynamically allocated data structures for this stream are freed. 332 This function discards any unprocessed input and does not flush any 333 pending output. 334 335 deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the 336 stream state was inconsistent, Z_DATA_ERROR if the stream was freed 337 prematurely (some input or output was discarded). In the error case, 338 msg may be set but then points to a static string (which must not be 339 deallocated). 340 */ 341 342 343 /* 344 ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm)); 345 346 Initializes the internal stream state for decompression. The fields 347 next_in, avail_in, zalloc, zfree and opaque must be initialized before by 348 the caller. If next_in is not Z_NULL and avail_in is large enough (the exact 349 value depends on the compression method), inflateInit determines the 350 compression method from the zlib header and allocates all data structures 351 accordingly; otherwise the allocation will be deferred to the first call of 352 inflate. If zalloc and zfree are set to Z_NULL, inflateInit updates them to 353 use default allocation functions. 354 355 inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough 356 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the 357 version assumed by the caller. msg is set to null if there is no error 358 message. inflateInit does not perform any decompression apart from reading 359 the zlib header if present: this will be done by inflate(). (So next_in and 360 avail_in may be modified, but next_out and avail_out are unchanged.) 361 */ 362 363 364 ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush)); 365 /* 366 inflate decompresses as much data as possible, and stops when the input 367 buffer becomes empty or the output buffer becomes full. It may introduce 368 some output latency (reading input without producing any output) except when 369 forced to flush. 370 371 The detailed semantics are as follows. inflate performs one or both of the 372 following actions: 373 374 - Decompress more input starting at next_in and update next_in and avail_in 375 accordingly. If not all input can be processed (because there is not 376 enough room in the output buffer), next_in is updated and processing 377 will resume at this point for the next call of inflate(). 378 379 - Provide more output starting at next_out and update next_out and avail_out 380 accordingly. inflate() provides as much output as possible, until there 381 is no more input data or no more space in the output buffer (see below 382 about the flush parameter). 383 384 Before the call of inflate(), the application should ensure that at least 385 one of the actions is possible, by providing more input and/or consuming 386 more output, and updating the next_* and avail_* values accordingly. 387 The application can consume the uncompressed output when it wants, for 388 example when the output buffer is full (avail_out == 0), or after each 389 call of inflate(). If inflate returns Z_OK and with zero avail_out, it 390 must be called again after making room in the output buffer because there 391 might be more output pending. 392 393 The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, 394 Z_FINISH, or Z_BLOCK. Z_SYNC_FLUSH requests that inflate() flush as much 395 output as possible to the output buffer. Z_BLOCK requests that inflate() stop 396 if and when it gets to the next deflate block boundary. When decoding the 397 zlib or gzip format, this will cause inflate() to return immediately after 398 the header and before the first block. When doing a raw inflate, inflate() 399 will go ahead and process the first block, and will return when it gets to 400 the end of that block, or when it runs out of data. 401 402 The Z_BLOCK option assists in appending to or combining deflate streams. 403 Also to assist in this, on return inflate() will set strm->data_type to the 404 number of unused bits in the last byte taken from strm->next_in, plus 64 405 if inflate() is currently decoding the last block in the deflate stream, 406 plus 128 if inflate() returned immediately after decoding an end-of-block 407 code or decoding the complete header up to just before the first byte of the 408 deflate stream. The end-of-block will not be indicated until all of the 409 uncompressed data from that block has been written to strm->next_out. The 410 number of unused bits may in general be greater than seven, except when 411 bit 7 of data_type is set, in which case the number of unused bits will be 412 less than eight. 413 414 inflate() should normally be called until it returns Z_STREAM_END or an 415 error. However if all decompression is to be performed in a single step 416 (a single call of inflate), the parameter flush should be set to 417 Z_FINISH. In this case all pending input is processed and all pending 418 output is flushed; avail_out must be large enough to hold all the 419 uncompressed data. (The size of the uncompressed data may have been saved 420 by the compressor for this purpose.) The next operation on this stream must 421 be inflateEnd to deallocate the decompression state. The use of Z_FINISH 422 is never required, but can be used to inform inflate that a faster approach 423 may be used for the single inflate() call. 424 425 In this implementation, inflate() always flushes as much output as 426 possible to the output buffer, and always uses the faster approach on the 427 first call. So the only effect of the flush parameter in this implementation 428 is on the return value of inflate(), as noted below, or when it returns early 429 because Z_BLOCK is used. 430 431 If a preset dictionary is needed after this call (see inflateSetDictionary 432 below), inflate sets strm->adler to the adler32 checksum of the dictionary 433 chosen by the compressor and returns Z_NEED_DICT; otherwise it sets 434 strm->adler to the adler32 checksum of all output produced so far (that is, 435 total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described 436 below. At the end of the stream, inflate() checks that its computed adler32 437 checksum is equal to that saved by the compressor and returns Z_STREAM_END 438 only if the checksum is correct. 439 440 inflate() will decompress and check either zlib-wrapped or gzip-wrapped 441 deflate data. The header type is detected automatically. Any information 442 contained in the gzip header is not retained, so applications that need that 443 information should instead use raw inflate, see inflateInit2() below, or 444 inflateBack() and perform their own processing of the gzip header and 445 trailer. 446 447 inflate() returns Z_OK if some progress has been made (more input processed 448 or more output produced), Z_STREAM_END if the end of the compressed data has 449 been reached and all uncompressed output has been produced, Z_NEED_DICT if a 450 preset dictionary is needed at this point, Z_DATA_ERROR if the input data was 451 corrupted (input stream not conforming to the zlib format or incorrect check 452 value), Z_STREAM_ERROR if the stream structure was inconsistent (for example 453 if next_in or next_out was NULL), Z_MEM_ERROR if there was not enough memory, 454 Z_BUF_ERROR if no progress is possible or if there was not enough room in the 455 output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and 456 inflate() can be called again with more input and more output space to 457 continue decompressing. If Z_DATA_ERROR is returned, the application may then 458 call inflateSync() to look for a good compression block if a partial recovery 459 of the data is desired. 460 */ 461 462 463 ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm)); 464 /* 465 All dynamically allocated data structures for this stream are freed. 466 This function discards any unprocessed input and does not flush any 467 pending output. 468 469 inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state 470 was inconsistent. In the error case, msg may be set but then points to a 471 static string (which must not be deallocated). 472 */ 473 474 /* Advanced functions */ 475 476 /* 477 The following functions are needed only in some special applications. 478 */ 479 480 /* 481 ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm, 482 int level, 483 int method, 484 int windowBits, 485 int memLevel, 486 int strategy)); 487 488 This is another version of deflateInit with more compression options. The 489 fields next_in, zalloc, zfree and opaque must be initialized before by 490 the caller. 491 492 The method parameter is the compression method. It must be Z_DEFLATED in 493 this version of the library. 494 495 The windowBits parameter is the base two logarithm of the window size 496 (the size of the history buffer). It should be in the range 8..15 for this 497 version of the library. Larger values of this parameter result in better 498 compression at the expense of memory usage. The default value is 15 if 499 deflateInit is used instead. 500 501 windowBits can also be -8..-15 for raw deflate. In this case, -windowBits 502 determines the window size. deflate() will then generate raw deflate data 503 with no zlib header or trailer, and will not compute an adler32 check value. 504 505 windowBits can also be greater than 15 for optional gzip encoding. Add 506 16 to windowBits to write a simple gzip header and trailer around the 507 compressed data instead of a zlib wrapper. The gzip header will have no 508 file name, no extra data, no comment, no modification time (set to zero), 509 no header crc, and the operating system will be set to 255 (unknown). If a 510 gzip stream is being written, strm->adler is a crc32 instead of an adler32. 511 512 The memLevel parameter specifies how much memory should be allocated 513 for the internal compression state. memLevel=1 uses minimum memory but 514 is slow and reduces compression ratio; memLevel=9 uses maximum memory 515 for optimal speed. The default value is 8. See zconf.h for total memory 516 usage as a function of windowBits and memLevel. 517 518 The strategy parameter is used to tune the compression algorithm. Use the 519 value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a 520 filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no 521 string match), or Z_RLE to limit match distances to one (run-length 522 encoding). Filtered data consists mostly of small values with a somewhat 523 random distribution. In this case, the compression algorithm is tuned to 524 compress them better. The effect of Z_FILTERED is to force more Huffman 525 coding and less string matching; it is somewhat intermediate between 526 Z_DEFAULT and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as fast as 527 Z_HUFFMAN_ONLY, but give better compression for PNG image data. The strategy 528 parameter only affects the compression ratio but not the correctness of the 529 compressed output even if it is not set appropriately. Z_FIXED prevents the 530 use of dynamic Huffman codes, allowing for a simpler decoder for special 531 applications. 532 533 deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 534 memory, Z_STREAM_ERROR if a parameter is invalid (such as an invalid 535 method). msg is set to null if there is no error message. deflateInit2 does 536 not perform any compression: this will be done by deflate(). 537 */ 538 539 ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm, 540 const Bytef *dictionary, 541 uInt dictLength)); 542 /* 543 Initializes the compression dictionary from the given byte sequence 544 without producing any compressed output. This function must be called 545 immediately after deflateInit, deflateInit2 or deflateReset, before any 546 call of deflate. The compressor and decompressor must use exactly the same 547 dictionary (see inflateSetDictionary). 548 549 The dictionary should consist of strings (byte sequences) that are likely 550 to be encountered later in the data to be compressed, with the most commonly 551 used strings preferably put towards the end of the dictionary. Using a 552 dictionary is most useful when the data to be compressed is short and can be 553 predicted with good accuracy; the data can then be compressed better than 554 with the default empty dictionary. 555 556 Depending on the size of the compression data structures selected by 557 deflateInit or deflateInit2, a part of the dictionary may in effect be 558 discarded, for example if the dictionary is larger than the window size in 559 deflate or deflate2. Thus the strings most likely to be useful should be 560 put at the end of the dictionary, not at the front. 561 562 Upon return of this function, strm->adler is set to the adler32 value 563 of the dictionary; the decompressor may later use this value to determine 564 which dictionary has been used by the compressor. (The adler32 value 565 applies to the whole dictionary even if only a subset of the dictionary is 566 actually used by the compressor.) If a raw deflate was requested, then the 567 adler32 value is not computed and strm->adler is not set. 568 569 deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a 570 parameter is invalid (such as NULL dictionary) or the stream state is 571 inconsistent (for example if deflate has already been called for this stream 572 or if the compression method is bsort). deflateSetDictionary does not 573 perform any compression: this will be done by deflate(). 574 */ 575 576 ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest, 577 z_streamp source)); 578 /* 579 Sets the destination stream as a complete copy of the source stream. 580 581 This function can be useful when several compression strategies will be 582 tried, for example when there are several ways of pre-processing the input 583 data with a filter. The streams that will be discarded should then be freed 584 by calling deflateEnd. Note that deflateCopy duplicates the internal 585 compression state which can be quite large, so this strategy is slow and 586 can consume lots of memory. 587 588 deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not 589 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent 590 (such as zalloc being NULL). msg is left unchanged in both source and 591 destination. 592 */ 593 594 ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm)); 595 /* 596 This function is equivalent to deflateEnd followed by deflateInit, 597 but does not free and reallocate all the internal compression state. 598 The stream will keep the same compression level and any other attributes 599 that may have been set by deflateInit2. 600 601 deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source 602 stream state was inconsistent (such as zalloc or state being NULL). 603 */ 604 605 ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm, 606 int level, 607 int strategy)); 608 /* 609 Dynamically update the compression level and compression strategy. The 610 interpretation of level and strategy is as in deflateInit2. This can be 611 used to switch between compression and straight copy of the input data, or 612 to switch to a different kind of input data requiring a different 613 strategy. If the compression level is changed, the input available so far 614 is compressed with the old level (and may be flushed); the new level will 615 take effect only at the next call of deflate(). 616 617 Before the call of deflateParams, the stream state must be set as for 618 a call of deflate(), since the currently available input may have to 619 be compressed and flushed. In particular, strm->avail_out must be non-zero. 620 621 deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source 622 stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR 623 if strm->avail_out was zero. 624 */ 625 626 ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm, 627 uLong sourceLen)); 628 /* 629 deflateBound() returns an upper bound on the compressed size after 630 deflation of sourceLen bytes. It must be called after deflateInit() 631 or deflateInit2(). This would be used to allocate an output buffer 632 for deflation in a single pass, and so would be called before deflate(). 633 */ 634 635 ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm, 636 int bits, 637 int value)); 638 /* 639 deflatePrime() inserts bits in the deflate output stream. The intent 640 is that this function is used to start off the deflate output with the 641 bits leftover from a previous deflate stream when appending to it. As such, 642 this function can only be used for raw deflate, and must be used before the 643 first deflate() call after a deflateInit2() or deflateReset(). bits must be 644 less than or equal to 16, and that many of the least significant bits of 645 value will be inserted in the output. 646 647 deflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source 648 stream state was inconsistent. 649 */ 650 651 ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm, 652 gz_headerp head)); 653 /* 654 deflateSetHeader() provides gzip header information for when a gzip 655 stream is requested by deflateInit2(). deflateSetHeader() may be called 656 after deflateInit2() or deflateReset() and before the first call of 657 deflate(). The text, time, os, extra field, name, and comment information 658 in the provided gz_header structure are written to the gzip header (xflag is 659 ignored -- the extra flags are set according to the compression level). The 660 caller must assure that, if not Z_NULL, name and comment are terminated with 661 a zero byte, and that if extra is not Z_NULL, that extra_len bytes are 662 available there. If hcrc is true, a gzip header crc is included. Note that 663 the current versions of the command-line version of gzip (up through version 664 1.3.x) do not support header crc's, and will report that it is a "multi-part 665 gzip file" and give up. 666 667 If deflateSetHeader is not used, the default gzip header has text false, 668 the time set to zero, and os set to 255, with no extra, name, or comment 669 fields. The gzip header is returned to the default state by deflateReset(). 670 671 deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source 672 stream state was inconsistent. 673 */ 674 675 /* 676 ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm, 677 int windowBits)); 678 679 This is another version of inflateInit with an extra parameter. The 680 fields next_in, avail_in, zalloc, zfree and opaque must be initialized 681 before by the caller. 682 683 The windowBits parameter is the base two logarithm of the maximum window 684 size (the size of the history buffer). It should be in the range 8..15 for 685 this version of the library. The default value is 15 if inflateInit is used 686 instead. windowBits must be greater than or equal to the windowBits value 687 provided to deflateInit2() while compressing, or it must be equal to 15 if 688 deflateInit2() was not used. If a compressed stream with a larger window 689 size is given as input, inflate() will return with the error code 690 Z_DATA_ERROR instead of trying to allocate a larger window. 691 692 windowBits can also be -8..-15 for raw inflate. In this case, -windowBits 693 determines the window size. inflate() will then process raw deflate data, 694 not looking for a zlib or gzip header, not generating a check value, and not 695 looking for any check values for comparison at the end of the stream. This 696 is for use with other formats that use the deflate compressed data format 697 such as zip. Those formats provide their own check values. If a custom 698 format is developed using the raw deflate format for compressed data, it is 699 recommended that a check value such as an adler32 or a crc32 be applied to 700 the uncompressed data as is done in the zlib, gzip, and zip formats. For 701 most applications, the zlib format should be used as is. Note that comments 702 above on the use in deflateInit2() applies to the magnitude of windowBits. 703 704 windowBits can also be greater than 15 for optional gzip decoding. Add 705 32 to windowBits to enable zlib and gzip decoding with automatic header 706 detection, or add 16 to decode only the gzip format (the zlib format will 707 return a Z_DATA_ERROR. If a gzip stream is being decoded, strm->adler is 708 a crc32 instead of an adler32. 709 710 inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 711 memory, Z_STREAM_ERROR if a parameter is invalid (such as a negative 712 memLevel). msg is set to null if there is no error message. inflateInit2 713 does not perform any decompression apart from reading the zlib header if 714 present: this will be done by inflate(). (So next_in and avail_in may be 715 modified, but next_out and avail_out are unchanged.) 716 */ 717 718 ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm, 719 const Bytef *dictionary, 720 uInt dictLength)); 721 /* 722 Initializes the decompression dictionary from the given uncompressed byte 723 sequence. This function must be called immediately after a call of inflate, 724 if that call returned Z_NEED_DICT. The dictionary chosen by the compressor 725 can be determined from the adler32 value returned by that call of inflate. 726 The compressor and decompressor must use exactly the same dictionary (see 727 deflateSetDictionary). For raw inflate, this function can be called 728 immediately after inflateInit2() or inflateReset() and before any call of 729 inflate() to set the dictionary. The application must insure that the 730 dictionary that was used for compression is provided. 731 732 inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a 733 parameter is invalid (such as NULL dictionary) or the stream state is 734 inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the 735 expected one (incorrect adler32 value). inflateSetDictionary does not 736 perform any decompression: this will be done by subsequent calls of 737 inflate(). 738 */ 739 740 ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm)); 741 /* 742 Skips invalid compressed data until a full flush point (see above the 743 description of deflate with Z_FULL_FLUSH) can be found, or until all 744 available input is skipped. No output is provided. 745 746 inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR 747 if no more input was provided, Z_DATA_ERROR if no flush point has been found, 748 or Z_STREAM_ERROR if the stream structure was inconsistent. In the success 749 case, the application may save the current current value of total_in which 750 indicates where valid compressed data was found. In the error case, the 751 application may repeatedly call inflateSync, providing more input each time, 752 until success or end of the input data. 753 */ 754 755 ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest, 756 z_streamp source)); 757 /* 758 Sets the destination stream as a complete copy of the source stream. 759 760 This function can be useful when randomly accessing a large stream. The 761 first pass through the stream can periodically record the inflate state, 762 allowing restarting inflate at those points when randomly accessing the 763 stream. 764 765 inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not 766 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent 767 (such as zalloc being NULL). msg is left unchanged in both source and 768 destination. 769 */ 770 771 ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm)); 772 /* 773 This function is equivalent to inflateEnd followed by inflateInit, 774 but does not free and reallocate all the internal decompression state. 775 The stream will keep attributes that may have been set by inflateInit2. 776 777 inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source 778 stream state was inconsistent (such as zalloc or state being NULL). 779 */ 780 781 ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm, 782 gz_headerp head)); 783 /* 784 inflateGetHeader() requests that gzip header information be stored in the 785 provided gz_header structure. inflateGetHeader() may be called after 786 inflateInit2() or inflateReset(), and before the first call of inflate(). 787 As inflate() processes the gzip stream, head->done is zero until the header 788 is completed, at which time head->done is set to one. If a zlib stream is 789 being decoded, then head->done is set to -1 to indicate that there will be 790 no gzip header information forthcoming. Note that Z_BLOCK can be used to 791 force inflate() to return immediately after header processing is complete 792 and before any actual data is decompressed. 793 794 The text, time, xflags, and os fields are filled in with the gzip header 795 contents. hcrc is set to true if there is a header CRC. (The header CRC 796 was valid if done is set to one.) If extra is not Z_NULL, then extra_max 797 contains the maximum number of bytes to write to extra. Once done is true, 798 extra_len contains the actual extra field length, and extra contains the 799 extra field, or that field truncated if extra_max is less than extra_len. 800 If name is not Z_NULL, then up to name_max characters are written there, 801 terminated with a zero unless the length is greater than name_max. If 802 comment is not Z_NULL, then up to comm_max characters are written there, 803 terminated with a zero unless the length is greater than comm_max. When 804 any of extra, name, or comment are not Z_NULL and the respective field is 805 not present in the header, then that field is set to Z_NULL to signal its 806 absence. This allows the use of deflateSetHeader() with the returned 807 structure to duplicate the header. However if those fields are set to 808 allocated memory, then the application will need to save those pointers 809 elsewhere so that they can be eventually freed. 810 811 If inflateGetHeader is not used, then the header information is simply 812 discarded. The header is always checked for validity, including the header 813 CRC if present. inflateReset() will reset the process to discard the header 814 information. The application would need to call inflateGetHeader() again to 815 retrieve the header from the next gzip stream. 816 817 inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source 818 stream state was inconsistent. 819 */ 820 821 /* 822 ZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits, 823 unsigned char FAR *window)); 824 825 Initialize the internal stream state for decompression using inflateBack() 826 calls. The fields zalloc, zfree and opaque in strm must be initialized 827 before the call. If zalloc and zfree are Z_NULL, then the default library- 828 derived memory allocation routines are used. windowBits is the base two 829 logarithm of the window size, in the range 8..15. window is a caller 830 supplied buffer of that size. Except for special applications where it is 831 assured that deflate was used with small window sizes, windowBits must be 15 832 and a 32K byte window must be supplied to be able to decompress general 833 deflate streams. 834 835 See inflateBack() for the usage of these routines. 836 837 inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of 838 the paramaters are invalid, Z_MEM_ERROR if the internal state could not 839 be allocated, or Z_VERSION_ERROR if the version of the library does not 840 match the version of the header file. 841 */ 842 843 typedef unsigned (*in_func) OF((void FAR *, unsigned char FAR * FAR *)); 844 typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned)); 845 846 ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm, 847 in_func in, void FAR *in_desc, 848 out_func out, void FAR *out_desc)); 849 /* 850 inflateBack() does a raw inflate with a single call using a call-back 851 interface for input and output. This is more efficient than inflate() for 852 file i/o applications in that it avoids copying between the output and the 853 sliding window by simply making the window itself the output buffer. This 854 function trusts the application to not change the output buffer passed by 855 the output function, at least until inflateBack() returns. 856 857 inflateBackInit() must be called first to allocate the internal state 858 and to initialize the state with the user-provided window buffer. 859 inflateBack() may then be used multiple times to inflate a complete, raw 860 deflate stream with each call. inflateBackEnd() is then called to free 861 the allocated state. 862 863 A raw deflate stream is one with no zlib or gzip header or trailer. 864 This routine would normally be used in a utility that reads zip or gzip 865 files and writes out uncompressed files. The utility would decode the 866 header and process the trailer on its own, hence this routine expects 867 only the raw deflate stream to decompress. This is different from the 868 normal behavior of inflate(), which expects either a zlib or gzip header and 869 trailer around the deflate stream. 870 871 inflateBack() uses two subroutines supplied by the caller that are then 872 called by inflateBack() for input and output. inflateBack() calls those 873 routines until it reads a complete deflate stream and writes out all of the 874 uncompressed data, or until it encounters an error. The function's 875 parameters and return types are defined above in the in_func and out_func 876 typedefs. inflateBack() will call in(in_desc, &buf) which should return the 877 number of bytes of provided input, and a pointer to that input in buf. If 878 there is no input available, in() must return zero--buf is ignored in that 879 case--and inflateBack() will return a buffer error. inflateBack() will call 880 out(out_desc, buf, len) to write the uncompressed data buf[0..len-1]. out() 881 should return zero on success, or non-zero on failure. If out() returns 882 non-zero, inflateBack() will return with an error. Neither in() nor out() 883 are permitted to change the contents of the window provided to 884 inflateBackInit(), which is also the buffer that out() uses to write from. 885 The length written by out() will be at most the window size. Any non-zero 886 amount of input may be provided by in(). 887 888 For convenience, inflateBack() can be provided input on the first call by 889 setting strm->next_in and strm->avail_in. If that input is exhausted, then 890 in() will be called. Therefore strm->next_in must be initialized before 891 calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called 892 immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in 893 must also be initialized, and then if strm->avail_in is not zero, input will 894 initially be taken from strm->next_in[0 .. strm->avail_in - 1]. 895 896 The in_desc and out_desc parameters of inflateBack() is passed as the 897 first parameter of in() and out() respectively when they are called. These 898 descriptors can be optionally used to pass any information that the caller- 899 supplied in() and out() functions need to do their job. 900 901 On return, inflateBack() will set strm->next_in and strm->avail_in to 902 pass back any unused input that was provided by the last in() call. The 903 return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR 904 if in() or out() returned an error, Z_DATA_ERROR if there was a format 905 error in the deflate stream (in which case strm->msg is set to indicate the 906 nature of the error), or Z_STREAM_ERROR if the stream was not properly 907 initialized. In the case of Z_BUF_ERROR, an input or output error can be 908 distinguished using strm->next_in which will be Z_NULL only if in() returned 909 an error. If strm->next is not Z_NULL, then the Z_BUF_ERROR was due to 910 out() returning non-zero. (in() will always be called before out(), so 911 strm->next_in is assured to be defined if out() returns non-zero.) Note 912 that inflateBack() cannot return Z_OK. 913 */ 914 915 ZEXTERN int ZEXPORT inflateBackEnd OF((z_streamp strm)); 916 /* 917 All memory allocated by inflateBackInit() is freed. 918 919 inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream 920 state was inconsistent. 921 */ 922 923 ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void)); 924 /* Return flags indicating compile-time options. 925 926 Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other: 927 1.0: size of uInt 928 3.2: size of uLong 929 5.4: size of voidpf (pointer) 930 7.6: size of z_off_t 931 932 Compiler, assembler, and debug options: 933 8: DEBUG 934 9: ASMV or ASMINF -- use ASM code 935 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention 936 11: 0 (reserved) 937 938 One-time table building (smaller code, but not thread-safe if true): 939 12: BUILDFIXED -- build static block decoding tables when needed 940 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed 941 14,15: 0 (reserved) 942 943 Library content (indicates missing functionality): 944 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking 945 deflate code when not needed) 946 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect 947 and decode gzip streams (to avoid linking crc code) 948 18-19: 0 (reserved) 949 950 Operation variations (changes in library functionality): 951 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate 952 21: FASTEST -- deflate algorithm with only one, lowest compression level 953 22,23: 0 (reserved) 954 955 The sprintf variant used by gzprintf (zero is best): 956 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format 957 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure! 958 26: 0 = returns value, 1 = void -- 1 means inferred string length returned 959 960 Remainder: 961 27-31: 0 (reserved) 962 */ 963 964 965 /* utility functions */ 966 967 /* 968 The following utility functions are implemented on top of the 969 basic stream-oriented functions. To simplify the interface, some 970 default options are assumed (compression level and memory usage, 971 standard memory allocation functions). The source code of these 972 utility functions can easily be modified if you need special options. 973 */ 974 975 ZEXTERN int ZEXPORT compress OF((Bytef *dest, uLongf *destLen, 976 const Bytef *source, uLong sourceLen)); 977 /* 978 Compresses the source buffer into the destination buffer. sourceLen is 979 the byte length of the source buffer. Upon entry, destLen is the total 980 size of the destination buffer, which must be at least the value returned 981 by compressBound(sourceLen). Upon exit, destLen is the actual size of the 982 compressed buffer. 983 This function can be used to compress a whole file at once if the 984 input file is mmap'ed. 985 compress returns Z_OK if success, Z_MEM_ERROR if there was not 986 enough memory, Z_BUF_ERROR if there was not enough room in the output 987 buffer. 988 */ 989 990 ZEXTERN int ZEXPORT compress2 OF((Bytef *dest, uLongf *destLen, 991 const Bytef *source, uLong sourceLen, 992 int level)); 993 /* 994 Compresses the source buffer into the destination buffer. The level 995 parameter has the same meaning as in deflateInit. sourceLen is the byte 996 length of the source buffer. Upon entry, destLen is the total size of the 997 destination buffer, which must be at least the value returned by 998 compressBound(sourceLen). Upon exit, destLen is the actual size of the 999 compressed buffer. 1000 1001 compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 1002 memory, Z_BUF_ERROR if there was not enough room in the output buffer, 1003 Z_STREAM_ERROR if the level parameter is invalid. 1004 */ 1005 1006 ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen)); 1007 /* 1008 compressBound() returns an upper bound on the compressed size after 1009 compress() or compress2() on sourceLen bytes. It would be used before 1010 a compress() or compress2() call to allocate the destination buffer. 1011 */ 1012 1013 ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen, 1014 const Bytef *source, uLong sourceLen)); 1015 /* 1016 Decompresses the source buffer into the destination buffer. sourceLen is 1017 the byte length of the source buffer. Upon entry, destLen is the total 1018 size of the destination buffer, which must be large enough to hold the 1019 entire uncompressed data. (The size of the uncompressed data must have 1020 been saved previously by the compressor and transmitted to the decompressor 1021 by some mechanism outside the scope of this compression library.) 1022 Upon exit, destLen is the actual size of the compressed buffer. 1023 This function can be used to decompress a whole file at once if the 1024 input file is mmap'ed. 1025 1026 uncompress returns Z_OK if success, Z_MEM_ERROR if there was not 1027 enough memory, Z_BUF_ERROR if there was not enough room in the output 1028 buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete. 1029 */ 1030 1031 1032 typedef voidp gzFile; 1033 1034 ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode)); 1035 /* 1036 Opens a gzip (.gz) file for reading or writing. The mode parameter 1037 is as in fopen ("rb" or "wb") but can also include a compression level 1038 ("wb9") or a strategy: 'f' for filtered data as in "wb6f", 'h' for 1039 Huffman only compression as in "wb1h", or 'R' for run-length encoding 1040 as in "wb1R". (See the description of deflateInit2 for more information 1041 about the strategy parameter.) 1042 1043 gzopen can be used to read a file which is not in gzip format; in this 1044 case gzread will directly read from the file without decompression. 1045 1046 gzopen returns NULL if the file could not be opened or if there was 1047 insufficient memory to allocate the (de)compression state; errno 1048 can be checked to distinguish the two cases (if errno is zero, the 1049 zlib error is Z_MEM_ERROR). */ 1050 1051 ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode)); 1052 /* 1053 gzdopen() associates a gzFile with the file descriptor fd. File 1054 descriptors are obtained from calls like open, dup, creat, pipe or 1055 fileno (in the file has been previously opened with fopen). 1056 The mode parameter is as in gzopen. 1057 The next call of gzclose on the returned gzFile will also close the 1058 file descriptor fd, just like fclose(fdopen(fd), mode) closes the file 1059 descriptor fd. If you want to keep fd open, use gzdopen(dup(fd), mode). 1060 gzdopen returns NULL if there was insufficient memory to allocate 1061 the (de)compression state. 1062 */ 1063 1064 ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy)); 1065 /* 1066 Dynamically update the compression level or strategy. See the description 1067 of deflateInit2 for the meaning of these parameters. 1068 gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not 1069 opened for writing. 1070 */ 1071 1072 ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len)); 1073 /* 1074 Reads the given number of uncompressed bytes from the compressed file. 1075 If the input file was not in gzip format, gzread copies the given number 1076 of bytes into the buffer. 1077 gzread returns the number of uncompressed bytes actually read (0 for 1078 end of file, -1 for error). */ 1079 1080 ZEXTERN int ZEXPORT gzwrite OF((gzFile file, 1081 voidpc buf, unsigned len)); 1082 /* 1083 Writes the given number of uncompressed bytes into the compressed file. 1084 gzwrite returns the number of uncompressed bytes actually written 1085 (0 in case of error). 1086 */ 1087 1088 ZEXTERN int ZEXPORTVA gzprintf OF((gzFile file, const char *format, ...)); 1089 /* 1090 Converts, formats, and writes the args to the compressed file under 1091 control of the format string, as in fprintf. gzprintf returns the number of 1092 uncompressed bytes actually written (0 in case of error). The number of 1093 uncompressed bytes written is limited to 4095. The caller should assure that 1094 this limit is not exceeded. If it is exceeded, then gzprintf() will return 1095 return an error (0) with nothing written. In this case, there may also be a 1096 buffer overflow with unpredictable consequences, which is possible only if 1097 zlib was compiled with the insecure functions sprintf() or vsprintf() 1098 because the secure snprintf() or vsnprintf() functions were not available. 1099 */ 1100 1101 ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s)); 1102 /* 1103 Writes the given null-terminated string to the compressed file, excluding 1104 the terminating null character. 1105 gzputs returns the number of characters written, or -1 in case of error. 1106 */ 1107 1108 ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len)); 1109 /* 1110 Reads bytes from the compressed file until len-1 characters are read, or 1111 a newline character is read and transferred to buf, or an end-of-file 1112 condition is encountered. The string is then terminated with a null 1113 character. 1114 gzgets returns buf, or Z_NULL in case of error. 1115 */ 1116 1117 ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c)); 1118 /* 1119 Writes c, converted to an unsigned char, into the compressed file. 1120 gzputc returns the value that was written, or -1 in case of error. 1121 */ 1122 1123 ZEXTERN int ZEXPORT gzgetc OF((gzFile file)); 1124 /* 1125 Reads one byte from the compressed file. gzgetc returns this byte 1126 or -1 in case of end of file or error. 1127 */ 1128 1129 ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file)); 1130 /* 1131 Push one character back onto the stream to be read again later. 1132 Only one character of push-back is allowed. gzungetc() returns the 1133 character pushed, or -1 on failure. gzungetc() will fail if a 1134 character has been pushed but not read yet, or if c is -1. The pushed 1135 character will be discarded if the stream is repositioned with gzseek() 1136 or gzrewind(). 1137 */ 1138 1139 ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush)); 1140 /* 1141 Flushes all pending output into the compressed file. The parameter 1142 flush is as in the deflate() function. The return value is the zlib 1143 error number (see function gzerror below). gzflush returns Z_OK if 1144 the flush parameter is Z_FINISH and all output could be flushed. 1145 gzflush should be called only when strictly necessary because it can 1146 degrade compression. 1147 */ 1148 1149 ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file, 1150 z_off_t offset, int whence)); 1151 /* 1152 Sets the starting position for the next gzread or gzwrite on the 1153 given compressed file. The offset represents a number of bytes in the 1154 uncompressed data stream. The whence parameter is defined as in lseek(2); 1155 the value SEEK_END is not supported. 1156 If the file is opened for reading, this function is emulated but can be 1157 extremely slow. If the file is opened for writing, only forward seeks are 1158 supported; gzseek then compresses a sequence of zeroes up to the new 1159 starting position. 1160 1161 gzseek returns the resulting offset location as measured in bytes from 1162 the beginning of the uncompressed stream, or -1 in case of error, in 1163 particular if the file is opened for writing and the new starting position 1164 would be before the current position. 1165 */ 1166 1167 ZEXTERN int ZEXPORT gzrewind OF((gzFile file)); 1168 /* 1169 Rewinds the given file. This function is supported only for reading. 1170 1171 gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET) 1172 */ 1173 1174 ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file)); 1175 /* 1176 Returns the starting position for the next gzread or gzwrite on the 1177 given compressed file. This position represents a number of bytes in the 1178 uncompressed data stream. 1179 1180 gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR) 1181 */ 1182 1183 ZEXTERN int ZEXPORT gzeof OF((gzFile file)); 1184 /* 1185 Returns 1 when EOF has previously been detected reading the given 1186 input stream, otherwise zero. 1187 */ 1188 1189 ZEXTERN int ZEXPORT gzclose OF((gzFile file)); 1190 /* 1191 Flushes all pending output if necessary, closes the compressed file 1192 and deallocates all the (de)compression state. The return value is the zlib 1193 error number (see function gzerror below). 1194 */ 1195 1196 ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum)); 1197 /* 1198 Returns the error message for the last error which occurred on the 1199 given compressed file. errnum is set to zlib error number. If an 1200 error occurred in the file system and not in the compression library, 1201 errnum is set to Z_ERRNO and the application may consult errno 1202 to get the exact error code. 1203 */ 1204 1205 ZEXTERN void ZEXPORT gzclearerr OF((gzFile file)); 1206 /* 1207 Clears the error and end-of-file flags for file. This is analogous to the 1208 clearerr() function in stdio. This is useful for continuing to read a gzip 1209 file that is being written concurrently. 1210 */ 1211 1212 /* checksum functions */ 1213 1214 /* 1215 These functions are not related to compression but are exported 1216 anyway because they might be useful in applications using the 1217 compression library. 1218 */ 1219 1220 ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len)); 1221 /* 1222 Update a running Adler-32 checksum with the bytes buf[0..len-1] and 1223 return the updated checksum. If buf is NULL, this function returns 1224 the required initial value for the checksum. 1225 An Adler-32 checksum is almost as reliable as a CRC32 but can be computed 1226 much faster. Usage example: 1227 1228 uLong adler = adler32(0L, Z_NULL, 0); 1229 1230 while (read_buffer(buffer, length) != EOF) { 1231 adler = adler32(adler, buffer, length); 1232 } 1233 if (adler != original_adler) error(); 1234 */ 1235 1236 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong adler1, uLong adler2, 1237 z_off_t len2)); 1238 /* 1239 Combine two Adler-32 checksums into one. For two sequences of bytes, seq1 1240 and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for 1241 each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of 1242 seq1 and seq2 concatenated, requiring only adler1, adler2, and len2. 1243 */ 1244 1245 ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len)); 1246 /* 1247 Update a running CRC-32 with the bytes buf[0..len-1] and return the 1248 updated CRC-32. If buf is NULL, this function returns the required initial 1249 value for the for the crc. Pre- and post-conditioning (one's complement) is 1250 performed within this function so it shouldn't be done by the application. 1251 Usage example: 1252 1253 uLong crc = crc32(0L, Z_NULL, 0); 1254 1255 while (read_buffer(buffer, length) != EOF) { 1256 crc = crc32(crc, buffer, length); 1257 } 1258 if (crc != original_crc) error(); 1259 */ 1260 1261 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2)); 1262 1263 /* 1264 Combine two CRC-32 check values into one. For two sequences of bytes, 1265 seq1 and seq2 with lengths len1 and len2, CRC-32 check values were 1266 calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32 1267 check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and 1268 len2. 1269 */ 1270 1271 1272 /* various hacks, don't look :) */ 1273 1274 /* deflateInit and inflateInit are macros to allow checking the zlib version 1275 * and the compiler's view of z_stream: 1276 */ 1277 ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level, 1278 const char *version, int stream_size)); 1279 ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm, 1280 const char *version, int stream_size)); 1281 ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method, 1282 int windowBits, int memLevel, 1283 int strategy, const char *version, 1284 int stream_size)); 1285 ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits, 1286 const char *version, int stream_size)); 1287 ZEXTERN int ZEXPORT inflateBackInit_ OF((z_streamp strm, int windowBits, 1288 unsigned char FAR *window, 1289 const char *version, 1290 int stream_size)); 1291 #define deflateInit(strm, level) \ 1292 deflateInit_((strm), (level), ZLIB_VERSION, sizeof(z_stream)) 1293 #define inflateInit(strm) \ 1294 inflateInit_((strm), ZLIB_VERSION, sizeof(z_stream)) 1295 #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \ 1296 deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\ 1297 (strategy), ZLIB_VERSION, sizeof(z_stream)) 1298 #define inflateInit2(strm, windowBits) \ 1299 inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream)) 1300 #define inflateBackInit(strm, windowBits, window) \ 1301 inflateBackInit_((strm), (windowBits), (window), \ 1302 ZLIB_VERSION, sizeof(z_stream)) 1303 1304 1305 #if !defined(ZUTIL_H) && !defined(NO_DUMMY_DECL) 1306 struct internal_state {int dummy;}; /* hack for buggy compilers */ 1307 #endif 1308 1309 ZEXTERN const char * ZEXPORT zError OF((int)); 1310 ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp z)); 1311 ZEXTERN const uLongf * ZEXPORT get_crc_table OF((void)); 1312 1313 #ifdef __cplusplus 1314 } 1315 #endif 1316 1317 #endif /* ZLIB_H */ 1318