1 /* zlib.h -- interface of the 'zlib' general purpose compression library 2 version 1.2.3.4, December 21st, 2009 3 4 Copyright (C) 1995-2009 Jean-loup Gailly and Mark Adler 5 6 This software is provided 'as-is', without any express or implied 7 warranty. In no event will the authors be held liable for any damages 8 arising from the use of this software. 9 10 Permission is granted to anyone to use this software for any purpose, 11 including commercial applications, and to alter it and redistribute it 12 freely, subject to the following restrictions: 13 14 1. The origin of this software must not be misrepresented; you must not 15 claim that you wrote the original software. If you use this software 16 in a product, an acknowledgment in the product documentation would be 17 appreciated but is not required. 18 2. Altered source versions must be plainly marked as such, and must not be 19 misrepresented as being the original software. 20 3. This notice may not be removed or altered from any source distribution. 21 22 Jean-loup Gailly Mark Adler 23 jloup (at) gzip.org madler (at) alumni.caltech.edu 24 25 26 The data format used by the zlib library is described by RFCs (Request for 27 Comments) 1950 to 1952 in the files http://www.ietf.org/rfc/rfc1950.txt 28 (zlib format), rfc1951.txt (deflate format) and rfc1952.txt (gzip format). 29 */ 30 31 #ifndef ZLIB_H 32 #define ZLIB_H 33 34 #include "zconf.h" 35 36 #ifdef __cplusplus 37 extern "C" { 38 #endif 39 40 #define ZLIB_VERSION "1.2.3.4" 41 #define ZLIB_VERNUM 0x1234 42 #define ZLIB_VER_MAJOR 1 43 #define ZLIB_VER_MINOR 2 44 #define ZLIB_VER_REVISION 3 45 46 /* 47 The 'zlib' compression library provides in-memory compression and 48 decompression functions, including integrity checks of the uncompressed 49 data. This version of the library supports only one compression method 50 (deflation) but other algorithms will be added later and will have the same 51 stream interface. 52 53 Compression can be done in a single step if the buffers are large 54 enough (for example if an input file is mmap'ed), or can be done by 55 repeated calls of the compression function. In the latter case, the 56 application must provide more input and/or consume the output 57 (providing more output space) before each call. 58 59 The compressed data format used by default by the in-memory functions is 60 the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped 61 around a deflate stream, which is itself documented in RFC 1951. 62 63 The library also supports reading and writing files in gzip (.gz) format 64 with an interface similar to that of stdio using the functions that start 65 with "gz". The gzip format is different from the zlib format. gzip is a 66 gzip wrapper, documented in RFC 1952, wrapped around a deflate stream. 67 68 This library can optionally read and write gzip streams in memory as well. 69 70 The zlib format was designed to be compact and fast for use in memory 71 and on communications channels. The gzip format was designed for single- 72 file compression on file systems, has a larger header than zlib to maintain 73 directory information, and uses a different, slower check method than zlib. 74 75 The library does not install any signal handler. The decoder checks 76 the consistency of the compressed data, so the library should never 77 crash even in case of corrupted input. 78 */ 79 80 typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size)); 81 typedef void (*free_func) OF((voidpf opaque, voidpf address)); 82 83 struct internal_state; 84 85 typedef struct z_stream_s { 86 Bytef *next_in; /* next input byte */ 87 uInt avail_in; /* number of bytes available at next_in */ 88 uLong total_in; /* total nb of input bytes read so far */ 89 90 Bytef *next_out; /* next output byte should be put there */ 91 uInt avail_out; /* remaining free space at next_out */ 92 uLong total_out; /* total nb of bytes output so far */ 93 94 char *msg; /* last error message, NULL if no error */ 95 struct internal_state FAR *state; /* not visible by applications */ 96 97 alloc_func zalloc; /* used to allocate the internal state */ 98 free_func zfree; /* used to free the internal state */ 99 voidpf opaque; /* private data object passed to zalloc and zfree */ 100 101 int data_type; /* best guess about the data type: binary or text */ 102 uLong adler; /* adler32 value of the uncompressed data */ 103 uLong reserved; /* reserved for future use */ 104 } z_stream; 105 106 typedef z_stream FAR *z_streamp; 107 108 /* 109 gzip header information passed to and from zlib routines. See RFC 1952 110 for more details on the meanings of these fields. 111 */ 112 typedef struct gz_header_s { 113 int text; /* true if compressed data believed to be text */ 114 uLong time; /* modification time */ 115 int xflags; /* extra flags (not used when writing a gzip file) */ 116 int os; /* operating system */ 117 Bytef *extra; /* pointer to extra field or Z_NULL if none */ 118 uInt extra_len; /* extra field length (valid if extra != Z_NULL) */ 119 uInt extra_max; /* space at extra (only when reading header) */ 120 Bytef *name; /* pointer to zero-terminated file name or Z_NULL */ 121 uInt name_max; /* space at name (only when reading header) */ 122 Bytef *comment; /* pointer to zero-terminated comment or Z_NULL */ 123 uInt comm_max; /* space at comment (only when reading header) */ 124 int hcrc; /* true if there was or will be a header crc */ 125 int done; /* true when done reading gzip header (not used 126 when writing a gzip file) */ 127 } gz_header; 128 129 typedef gz_header FAR *gz_headerp; 130 131 /* 132 The application must update next_in and avail_in when avail_in has 133 dropped to zero. It must update next_out and avail_out when avail_out 134 has dropped to zero. The application must initialize zalloc, zfree and 135 opaque before calling the init function. All other fields are set by the 136 compression library and must not be updated by the application. 137 138 The opaque value provided by the application will be passed as the first 139 parameter for calls of zalloc and zfree. This can be useful for custom 140 memory management. The compression library attaches no meaning to the 141 opaque value. 142 143 zalloc must return Z_NULL if there is not enough memory for the object. 144 If zlib is used in a multi-threaded application, zalloc and zfree must be 145 thread safe. 146 147 On 16-bit systems, the functions zalloc and zfree must be able to allocate 148 exactly 65536 bytes, but will not be required to allocate more than this 149 if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, 150 pointers returned by zalloc for objects of exactly 65536 bytes *must* 151 have their offset normalized to zero. The default allocation function 152 provided by this library ensures this (see zutil.c). To reduce memory 153 requirements and avoid any allocation of 64K objects, at the expense of 154 compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h). 155 156 The fields total_in and total_out can be used for statistics or 157 progress reports. After compression, total_in holds the total size of 158 the uncompressed data and may be saved for use in the decompressor 159 (particularly if the decompressor wants to decompress everything in 160 a single step). 161 */ 162 163 /* constants */ 164 165 #define Z_NO_FLUSH 0 166 #define Z_PARTIAL_FLUSH 1 167 #define Z_SYNC_FLUSH 2 168 #define Z_FULL_FLUSH 3 169 #define Z_FINISH 4 170 #define Z_BLOCK 5 171 #define Z_TREES 6 172 /* Allowed flush values; see deflate() and inflate() below for details */ 173 174 #define Z_OK 0 175 #define Z_STREAM_END 1 176 #define Z_NEED_DICT 2 177 #define Z_ERRNO (-1) 178 #define Z_STREAM_ERROR (-2) 179 #define Z_DATA_ERROR (-3) 180 #define Z_MEM_ERROR (-4) 181 #define Z_BUF_ERROR (-5) 182 #define Z_VERSION_ERROR (-6) 183 /* Return codes for the compression/decompression functions. Negative 184 * values are errors, positive values are used for special but normal events. 185 */ 186 187 #define Z_NO_COMPRESSION 0 188 #define Z_BEST_SPEED 1 189 #define Z_BEST_COMPRESSION 9 190 #define Z_DEFAULT_COMPRESSION (-1) 191 /* compression levels */ 192 193 #define Z_FILTERED 1 194 #define Z_HUFFMAN_ONLY 2 195 #define Z_RLE 3 196 #define Z_FIXED 4 197 #define Z_DEFAULT_STRATEGY 0 198 /* compression strategy; see deflateInit2() below for details */ 199 200 #define Z_BINARY 0 201 #define Z_TEXT 1 202 #define Z_ASCII Z_TEXT /* for compatibility with 1.2.2 and earlier */ 203 #define Z_UNKNOWN 2 204 /* Possible values of the data_type field (though see inflate()) */ 205 206 #define Z_DEFLATED 8 207 /* The deflate compression method (the only one supported in this version) */ 208 209 #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */ 210 211 #define zlib_version zlibVersion() 212 /* for compatibility with versions < 1.0.2 */ 213 214 /* basic functions */ 215 216 ZEXTERN const char * ZEXPORT zlibVersion OF((void)); 217 /* The application can compare zlibVersion and ZLIB_VERSION for consistency. 218 If the first character differs, the library code actually used is 219 not compatible with the zlib.h header file used by the application. 220 This check is automatically made by deflateInit and inflateInit. 221 */ 222 223 /* 224 ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level)); 225 226 Initializes the internal stream state for compression. The fields 227 zalloc, zfree and opaque must be initialized before by the caller. 228 If zalloc and zfree are set to Z_NULL, deflateInit updates them to 229 use default allocation functions. 230 231 The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9: 232 1 gives best speed, 9 gives best compression, 0 gives no compression at 233 all (the input data is simply copied a block at a time). 234 Z_DEFAULT_COMPRESSION requests a default compromise between speed and 235 compression (currently equivalent to level 6). 236 237 deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not 238 enough memory, Z_STREAM_ERROR if level is not a valid compression level, 239 Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible 240 with the version assumed by the caller (ZLIB_VERSION). 241 msg is set to null if there is no error message. deflateInit does not 242 perform any compression: this will be done by deflate(). 243 */ 244 245 246 ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush)); 247 /* 248 deflate compresses as much data as possible, and stops when the input 249 buffer becomes empty or the output buffer becomes full. It may introduce some 250 output latency (reading input without producing any output) except when 251 forced to flush. 252 253 The detailed semantics are as follows. deflate performs one or both of the 254 following actions: 255 256 - Compress more input starting at next_in and update next_in and avail_in 257 accordingly. If not all input can be processed (because there is not 258 enough room in the output buffer), next_in and avail_in are updated and 259 processing will resume at this point for the next call of deflate(). 260 261 - Provide more output starting at next_out and update next_out and avail_out 262 accordingly. This action is forced if the parameter flush is non zero. 263 Forcing flush frequently degrades the compression ratio, so this parameter 264 should be set only when necessary (in interactive applications). 265 Some output may be provided even if flush is not set. 266 267 Before the call of deflate(), the application should ensure that at least 268 one of the actions is possible, by providing more input and/or consuming 269 more output, and updating avail_in or avail_out accordingly; avail_out 270 should never be zero before the call. The application can consume the 271 compressed output when it wants, for example when the output buffer is full 272 (avail_out == 0), or after each call of deflate(). If deflate returns Z_OK 273 and with zero avail_out, it must be called again after making room in the 274 output buffer because there might be more output pending. 275 276 Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to 277 decide how much data to accumulate before producing output, in order to 278 maximize compression. 279 280 If the parameter flush is set to Z_SYNC_FLUSH, all pending output is 281 flushed to the output buffer and the output is aligned on a byte boundary, so 282 that the decompressor can get all input data available so far. (In particular 283 avail_in is zero after the call if enough output space has been provided 284 before the call.) Flushing may degrade compression for some compression 285 algorithms and so it should be used only when necessary. This completes the 286 current deflate block and follows it with an empty stored block that is three 287 bits plus filler bits to the next byte, followed by four bytes (00 00 ff ff). 288 289 If flush is set to Z_PARTIAL_FLUSH, all pending output is flushed to the 290 output buffer, but the output is not aligned to a byte boundary. All of the 291 input data so far will be available to the decompressor, as for Z_SYNC_FLUSH. 292 This completes the current deflate block and follows it with an empty fixed 293 codes block that is 10 bits long. This assures that enough bytes are output 294 in order for the decompressor to finish the block before the empty fixed code 295 block. 296 297 If flush is set to Z_BLOCK, a deflate block is completed and emitted, as 298 for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to 299 seven bits of the current block are held to be written as the next byte after 300 the next deflate block is completed. In this case, the decompressor may not 301 be provided enough bits at this point in order to complete decompression of 302 the data provided so far to the compressor. It may need to wait for the next 303 block to be emitted. This is for advanced applications that need to control 304 the emission of deflate blocks. 305 306 If flush is set to Z_FULL_FLUSH, all output is flushed as with 307 Z_SYNC_FLUSH, and the compression state is reset so that decompression can 308 restart from this point if previous compressed data has been damaged or if 309 random access is desired. Using Z_FULL_FLUSH too often can seriously degrade 310 compression. 311 312 If deflate returns with avail_out == 0, this function must be called again 313 with the same value of the flush parameter and more output space (updated 314 avail_out), until the flush is complete (deflate returns with non-zero 315 avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that 316 avail_out is greater than six to avoid repeated flush markers due to 317 avail_out == 0 on return. 318 319 If the parameter flush is set to Z_FINISH, pending input is processed, 320 pending output is flushed and deflate returns with Z_STREAM_END if there 321 was enough output space; if deflate returns with Z_OK, this function must be 322 called again with Z_FINISH and more output space (updated avail_out) but no 323 more input data, until it returns with Z_STREAM_END or an error. After 324 deflate has returned Z_STREAM_END, the only possible operations on the 325 stream are deflateReset or deflateEnd. 326 327 Z_FINISH can be used immediately after deflateInit if all the compression 328 is to be done in a single step. In this case, avail_out must be at least 329 the value returned by deflateBound (see below). If deflate does not return 330 Z_STREAM_END, then it must be called again as described above. 331 332 deflate() sets strm->adler to the adler32 checksum of all input read 333 so far (that is, total_in bytes). 334 335 deflate() may update strm->data_type if it can make a good guess about 336 the input data type (Z_BINARY or Z_TEXT). In doubt, the data is considered 337 binary. This field is only for information purposes and does not affect 338 the compression algorithm in any manner. 339 340 deflate() returns Z_OK if some progress has been made (more input 341 processed or more output produced), Z_STREAM_END if all input has been 342 consumed and all output has been produced (only when flush is set to 343 Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example 344 if next_in or next_out was Z_NULL), Z_BUF_ERROR if no progress is possible 345 (for example avail_in or avail_out was zero). Note that Z_BUF_ERROR is not 346 fatal, and deflate() can be called again with more input and more output 347 space to continue compressing. 348 */ 349 350 351 ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm)); 352 /* 353 All dynamically allocated data structures for this stream are freed. 354 This function discards any unprocessed input and does not flush any 355 pending output. 356 357 deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the 358 stream state was inconsistent, Z_DATA_ERROR if the stream was freed 359 prematurely (some input or output was discarded). In the error case, 360 msg may be set but then points to a static string (which must not be 361 deallocated). 362 */ 363 364 365 /* 366 ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm)); 367 368 Initializes the internal stream state for decompression. The fields 369 next_in, avail_in, zalloc, zfree and opaque must be initialized before by 370 the caller. If next_in is not Z_NULL and avail_in is large enough (the exact 371 value depends on the compression method), inflateInit determines the 372 compression method from the zlib header and allocates all data structures 373 accordingly; otherwise the allocation will be deferred to the first call of 374 inflate. If zalloc and zfree are set to Z_NULL, inflateInit updates them to 375 use default allocation functions. 376 377 inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough 378 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the 379 version assumed by the caller, or Z_STREAM_ERROR if the parameters are 380 invalid, such as a null pointer to the structure. msg is set to null if 381 there is no error message. inflateInit does not perform any decompression 382 apart from possibly reading the zlib header if present: actual decompression 383 will be done by inflate(). (So next_in and avail_in may be modified, but 384 next_out and avail_out are unused and unchanged.) The current 385 implementation of inflateInit() does not process any header information -- 386 that is deferred until inflate() is called. 387 */ 388 389 390 ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush)); 391 /* 392 inflate decompresses as much data as possible, and stops when the input 393 buffer becomes empty or the output buffer becomes full. It may introduce 394 some output latency (reading input without producing any output) except when 395 forced to flush. 396 397 The detailed semantics are as follows. inflate performs one or both of the 398 following actions: 399 400 - Decompress more input starting at next_in and update next_in and avail_in 401 accordingly. If not all input can be processed (because there is not 402 enough room in the output buffer), next_in is updated and processing 403 will resume at this point for the next call of inflate(). 404 405 - Provide more output starting at next_out and update next_out and avail_out 406 accordingly. inflate() provides as much output as possible, until there 407 is no more input data or no more space in the output buffer (see below 408 about the flush parameter). 409 410 Before the call of inflate(), the application should ensure that at least 411 one of the actions is possible, by providing more input and/or consuming 412 more output, and updating the next_* and avail_* values accordingly. 413 The application can consume the uncompressed output when it wants, for 414 example when the output buffer is full (avail_out == 0), or after each 415 call of inflate(). If inflate returns Z_OK and with zero avail_out, it 416 must be called again after making room in the output buffer because there 417 might be more output pending. 418 419 The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, Z_FINISH, 420 Z_BLOCK, or Z_TREES. Z_SYNC_FLUSH requests that inflate() flush as much 421 output as possible to the output buffer. Z_BLOCK requests that inflate() stop 422 if and when it gets to the next deflate block boundary. When decoding the 423 zlib or gzip format, this will cause inflate() to return immediately after 424 the header and before the first block. When doing a raw inflate, inflate() 425 will go ahead and process the first block, and will return when it gets to 426 the end of that block, or when it runs out of data. 427 428 The Z_BLOCK option assists in appending to or combining deflate streams. 429 Also to assist in this, on return inflate() will set strm->data_type to the 430 number of unused bits in the last byte taken from strm->next_in, plus 64 431 if inflate() is currently decoding the last block in the deflate stream, 432 plus 128 if inflate() returned immediately after decoding an end-of-block 433 code or decoding the complete header up to just before the first byte of the 434 deflate stream. The end-of-block will not be indicated until all of the 435 uncompressed data from that block has been written to strm->next_out. The 436 number of unused bits may in general be greater than seven, except when 437 bit 7 of data_type is set, in which case the number of unused bits will be 438 less than eight. data_type is set as noted here every time inflate() 439 returns for all flush options, and so can be used to determine the amount 440 of currently consumed input in bits. 441 442 The Z_TREES option behaves as Z_BLOCK does, but it also returns when the 443 end of each deflate block header is reached, before any actual data in that 444 block is decoded. This allows the caller to determine the length of the 445 deflate block header for later use in random access within a deflate block. 446 256 is added to the value of strm->data_type when inflate() returns 447 immediately after reaching the end of the deflate block header. 448 449 inflate() should normally be called until it returns Z_STREAM_END or an 450 error. However if all decompression is to be performed in a single step 451 (a single call of inflate), the parameter flush should be set to 452 Z_FINISH. In this case all pending input is processed and all pending 453 output is flushed; avail_out must be large enough to hold all the 454 uncompressed data. (The size of the uncompressed data may have been saved 455 by the compressor for this purpose.) The next operation on this stream must 456 be inflateEnd to deallocate the decompression state. The use of Z_FINISH 457 is never required, but can be used to inform inflate that a faster approach 458 may be used for the single inflate() call. 459 460 In this implementation, inflate() always flushes as much output as 461 possible to the output buffer, and always uses the faster approach on the 462 first call. So the only effect of the flush parameter in this implementation 463 is on the return value of inflate(), as noted below, or when it returns early 464 because Z_BLOCK or Z_TREES is used. 465 466 If a preset dictionary is needed after this call (see inflateSetDictionary 467 below), inflate sets strm->adler to the adler32 checksum of the dictionary 468 chosen by the compressor and returns Z_NEED_DICT; otherwise it sets 469 strm->adler to the adler32 checksum of all output produced so far (that is, 470 total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described 471 below. At the end of the stream, inflate() checks that its computed adler32 472 checksum is equal to that saved by the compressor and returns Z_STREAM_END 473 only if the checksum is correct. 474 475 inflate() can decompress and check either zlib-wrapped or gzip-wrapped 476 deflate data. The header type is detected automatically, if requested when 477 initializing with inflateInit2(). Any information contained in the gzip 478 header is not retained, so applications that need that information should 479 instead use raw inflate, see inflateInit2() below, or inflateBack() and 480 perform their own processing of the gzip header and trailer. 481 482 inflate() returns Z_OK if some progress has been made (more input processed 483 or more output produced), Z_STREAM_END if the end of the compressed data has 484 been reached and all uncompressed output has been produced, Z_NEED_DICT if a 485 preset dictionary is needed at this point, Z_DATA_ERROR if the input data was 486 corrupted (input stream not conforming to the zlib format or incorrect check 487 value), Z_STREAM_ERROR if the stream structure was inconsistent (for example 488 next_in or next_out was Z_NULL), Z_MEM_ERROR if there was not enough memory, 489 Z_BUF_ERROR if no progress is possible or if there was not enough room in the 490 output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and 491 inflate() can be called again with more input and more output space to 492 continue decompressing. If Z_DATA_ERROR is returned, the application may then 493 call inflateSync() to look for a good compression block if a partial recovery 494 of the data is desired. 495 */ 496 497 498 ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm)); 499 /* 500 All dynamically allocated data structures for this stream are freed. 501 This function discards any unprocessed input and does not flush any 502 pending output. 503 504 inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state 505 was inconsistent. In the error case, msg may be set but then points to a 506 static string (which must not be deallocated). 507 */ 508 509 /* Advanced functions */ 510 511 /* 512 The following functions are needed only in some special applications. 513 */ 514 515 /* 516 ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm, 517 int level, 518 int method, 519 int windowBits, 520 int memLevel, 521 int strategy)); 522 523 This is another version of deflateInit with more compression options. The 524 fields next_in, zalloc, zfree and opaque must be initialized before by 525 the caller. 526 527 The method parameter is the compression method. It must be Z_DEFLATED in 528 this version of the library. 529 530 The windowBits parameter is the base two logarithm of the window size 531 (the size of the history buffer). It should be in the range 8..15 for this 532 version of the library. Larger values of this parameter result in better 533 compression at the expense of memory usage. The default value is 15 if 534 deflateInit is used instead. 535 536 windowBits can also be -8..-15 for raw deflate. In this case, -windowBits 537 determines the window size. deflate() will then generate raw deflate data 538 with no zlib header or trailer, and will not compute an adler32 check value. 539 540 windowBits can also be greater than 15 for optional gzip encoding. Add 541 16 to windowBits to write a simple gzip header and trailer around the 542 compressed data instead of a zlib wrapper. The gzip header will have no 543 file name, no extra data, no comment, no modification time (set to zero), 544 no header crc, and the operating system will be set to 255 (unknown). If a 545 gzip stream is being written, strm->adler is a crc32 instead of an adler32. 546 547 The memLevel parameter specifies how much memory should be allocated 548 for the internal compression state. memLevel=1 uses minimum memory but 549 is slow and reduces compression ratio; memLevel=9 uses maximum memory 550 for optimal speed. The default value is 8. See zconf.h for total memory 551 usage as a function of windowBits and memLevel. 552 553 The strategy parameter is used to tune the compression algorithm. Use the 554 value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a 555 filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no 556 string match), or Z_RLE to limit match distances to one (run-length 557 encoding). Filtered data consists mostly of small values with a somewhat 558 random distribution. In this case, the compression algorithm is tuned to 559 compress them better. The effect of Z_FILTERED is to force more Huffman 560 coding and less string matching; it is somewhat intermediate between 561 Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as 562 fast as Z_HUFFMAN_ONLY, but give better compression for PNG image data. The 563 strategy parameter only affects the compression ratio but not the 564 correctness of the compressed output even if it is not set appropriately. 565 Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler 566 decoder for special applications. 567 568 deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 569 memory, Z_STREAM_ERROR if a parameter is invalid (such as an invalid 570 method). msg is set to null if there is no error message. deflateInit2 does 571 not perform any compression: this will be done by deflate(). 572 */ 573 574 ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm, 575 const Bytef *dictionary, 576 uInt dictLength)); 577 /* 578 Initializes the compression dictionary from the given byte sequence 579 without producing any compressed output. This function must be called 580 immediately after deflateInit, deflateInit2 or deflateReset, before any 581 call of deflate. The compressor and decompressor must use exactly the same 582 dictionary (see inflateSetDictionary). 583 584 The dictionary should consist of strings (byte sequences) that are likely 585 to be encountered later in the data to be compressed, with the most commonly 586 used strings preferably put towards the end of the dictionary. Using a 587 dictionary is most useful when the data to be compressed is short and can be 588 predicted with good accuracy; the data can then be compressed better than 589 with the default empty dictionary. 590 591 Depending on the size of the compression data structures selected by 592 deflateInit or deflateInit2, a part of the dictionary may in effect be 593 discarded, for example if the dictionary is larger than the window size 594 provided in deflateInit or deflateInit2. Thus the strings most likely to be 595 useful should be put at the end of the dictionary, not at the front. In 596 addition, the current implementation of deflate will use at most the window 597 size minus 262 bytes of the provided dictionary. 598 599 Upon return of this function, strm->adler is set to the adler32 value 600 of the dictionary; the decompressor may later use this value to determine 601 which dictionary has been used by the compressor. (The adler32 value 602 applies to the whole dictionary even if only a subset of the dictionary is 603 actually used by the compressor.) If a raw deflate was requested, then the 604 adler32 value is not computed and strm->adler is not set. 605 606 deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a 607 parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is 608 inconsistent (for example if deflate has already been called for this stream 609 or if the compression method is bsort). deflateSetDictionary does not 610 perform any compression: this will be done by deflate(). 611 */ 612 613 ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest, 614 z_streamp source)); 615 /* 616 Sets the destination stream as a complete copy of the source stream. 617 618 This function can be useful when several compression strategies will be 619 tried, for example when there are several ways of pre-processing the input 620 data with a filter. The streams that will be discarded should then be freed 621 by calling deflateEnd. Note that deflateCopy duplicates the internal 622 compression state which can be quite large, so this strategy is slow and 623 can consume lots of memory. 624 625 deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not 626 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent 627 (such as zalloc being Z_NULL). msg is left unchanged in both source and 628 destination. 629 */ 630 631 ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm)); 632 /* 633 This function is equivalent to deflateEnd followed by deflateInit, 634 but does not free and reallocate all the internal compression state. 635 The stream will keep the same compression level and any other attributes 636 that may have been set by deflateInit2. 637 638 deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source 639 stream state was inconsistent (such as zalloc or state being Z_NULL). 640 */ 641 642 ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm, 643 int level, 644 int strategy)); 645 /* 646 Dynamically update the compression level and compression strategy. The 647 interpretation of level and strategy is as in deflateInit2. This can be 648 used to switch between compression and straight copy of the input data, or 649 to switch to a different kind of input data requiring a different 650 strategy. If the compression level is changed, the input available so far 651 is compressed with the old level (and may be flushed); the new level will 652 take effect only at the next call of deflate(). 653 654 Before the call of deflateParams, the stream state must be set as for 655 a call of deflate(), since the currently available input may have to 656 be compressed and flushed. In particular, strm->avail_out must be non-zero. 657 658 deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source 659 stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR 660 if strm->avail_out was zero. 661 */ 662 663 ZEXTERN int ZEXPORT deflateTune OF((z_streamp strm, 664 int good_length, 665 int max_lazy, 666 int nice_length, 667 int max_chain)); 668 /* 669 Fine tune deflate's internal compression parameters. This should only be 670 used by someone who understands the algorithm used by zlib's deflate for 671 searching for the best matching string, and even then only by the most 672 fanatic optimizer trying to squeeze out the last compressed bit for their 673 specific input data. Read the deflate.c source code for the meaning of the 674 max_lazy, good_length, nice_length, and max_chain parameters. 675 676 deflateTune() can be called after deflateInit() or deflateInit2(), and 677 returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream. 678 */ 679 680 ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm, 681 uLong sourceLen)); 682 /* 683 deflateBound() returns an upper bound on the compressed size after 684 deflation of sourceLen bytes. It must be called after deflateInit() or 685 deflateInit2(), and after deflateSetHeader(), if used. This would be used 686 to allocate an output buffer for deflation in a single pass, and so would be 687 called before deflate(). 688 */ 689 690 ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm, 691 int bits, 692 int value)); 693 /* 694 deflatePrime() inserts bits in the deflate output stream. The intent 695 is that this function is used to start off the deflate output with the 696 bits leftover from a previous deflate stream when appending to it. As such, 697 this function can only be used for raw deflate, and must be used before the 698 first deflate() call after a deflateInit2() or deflateReset(). bits must be 699 less than or equal to 16, and that many of the least significant bits of 700 value will be inserted in the output. 701 702 deflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source 703 stream state was inconsistent. 704 */ 705 706 ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm, 707 gz_headerp head)); 708 /* 709 deflateSetHeader() provides gzip header information for when a gzip 710 stream is requested by deflateInit2(). deflateSetHeader() may be called 711 after deflateInit2() or deflateReset() and before the first call of 712 deflate(). The text, time, os, extra field, name, and comment information 713 in the provided gz_header structure are written to the gzip header (xflag is 714 ignored -- the extra flags are set according to the compression level). The 715 caller must assure that, if not Z_NULL, name and comment are terminated with 716 a zero byte, and that if extra is not Z_NULL, that extra_len bytes are 717 available there. If hcrc is true, a gzip header crc is included. Note that 718 the current versions of the command-line version of gzip (up through version 719 1.3.x) do not support header crc's, and will report that it is a "multi-part 720 gzip file" and give up. 721 722 If deflateSetHeader is not used, the default gzip header has text false, 723 the time set to zero, and os set to 255, with no extra, name, or comment 724 fields. The gzip header is returned to the default state by deflateReset(). 725 726 deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source 727 stream state was inconsistent. 728 */ 729 730 /* 731 ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm, 732 int windowBits)); 733 734 This is another version of inflateInit with an extra parameter. The 735 fields next_in, avail_in, zalloc, zfree and opaque must be initialized 736 before by the caller. 737 738 The windowBits parameter is the base two logarithm of the maximum window 739 size (the size of the history buffer). It should be in the range 8..15 for 740 this version of the library. The default value is 15 if inflateInit is used 741 instead. windowBits must be greater than or equal to the windowBits value 742 provided to deflateInit2() while compressing, or it must be equal to 15 if 743 deflateInit2() was not used. If a compressed stream with a larger window 744 size is given as input, inflate() will return with the error code 745 Z_DATA_ERROR instead of trying to allocate a larger window. 746 747 windowBits can also be -8..-15 for raw inflate. In this case, -windowBits 748 determines the window size. inflate() will then process raw deflate data, 749 not looking for a zlib or gzip header, not generating a check value, and not 750 looking for any check values for comparison at the end of the stream. This 751 is for use with other formats that use the deflate compressed data format 752 such as zip. Those formats provide their own check values. If a custom 753 format is developed using the raw deflate format for compressed data, it is 754 recommended that a check value such as an adler32 or a crc32 be applied to 755 the uncompressed data as is done in the zlib, gzip, and zip formats. For 756 most applications, the zlib format should be used as is. Note that comments 757 above on the use in deflateInit2() applies to the magnitude of windowBits. 758 759 windowBits can also be greater than 15 for optional gzip decoding. Add 760 32 to windowBits to enable zlib and gzip decoding with automatic header 761 detection, or add 16 to decode only the gzip format (the zlib format will 762 return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is 763 a crc32 instead of an adler32. 764 765 inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 766 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the 767 version assumed by the caller, or Z_STREAM_ERROR if the parameters are 768 invalid, such as a null pointer to the structure. msg is set to null if 769 there is no error message. inflateInit2 does not perform any decompression 770 apart from possibly reading the zlib header if present: actual decompression 771 will be done by inflate(). (So next_in and avail_in may be modified, but 772 next_out and avail_out are unused and unchanged.) The current 773 implementation of inflateInit2() does not process any header information -- 774 that is deferred until inflate() is called. 775 */ 776 777 ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm, 778 const Bytef *dictionary, 779 uInt dictLength)); 780 /* 781 Initializes the decompression dictionary from the given uncompressed byte 782 sequence. This function must be called immediately after a call of inflate, 783 if that call returned Z_NEED_DICT. The dictionary chosen by the compressor 784 can be determined from the adler32 value returned by that call of inflate. 785 The compressor and decompressor must use exactly the same dictionary (see 786 deflateSetDictionary). For raw inflate, this function can be called 787 immediately after inflateInit2() or inflateReset() and before any call of 788 inflate() to set the dictionary. The application must insure that the 789 dictionary that was used for compression is provided. 790 791 inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a 792 parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is 793 inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the 794 expected one (incorrect adler32 value). inflateSetDictionary does not 795 perform any decompression: this will be done by subsequent calls of 796 inflate(). 797 */ 798 799 ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm)); 800 /* 801 Skips invalid compressed data until a full flush point (see above the 802 description of deflate with Z_FULL_FLUSH) can be found, or until all 803 available input is skipped. No output is provided. 804 805 inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR 806 if no more input was provided, Z_DATA_ERROR if no flush point has been found, 807 or Z_STREAM_ERROR if the stream structure was inconsistent. In the success 808 case, the application may save the current current value of total_in which 809 indicates where valid compressed data was found. In the error case, the 810 application may repeatedly call inflateSync, providing more input each time, 811 until success or end of the input data. 812 */ 813 814 ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest, 815 z_streamp source)); 816 /* 817 Sets the destination stream as a complete copy of the source stream. 818 819 This function can be useful when randomly accessing a large stream. The 820 first pass through the stream can periodically record the inflate state, 821 allowing restarting inflate at those points when randomly accessing the 822 stream. 823 824 inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not 825 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent 826 (such as zalloc being Z_NULL). msg is left unchanged in both source and 827 destination. 828 */ 829 830 ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm)); 831 /* 832 This function is equivalent to inflateEnd followed by inflateInit, 833 but does not free and reallocate all the internal decompression state. 834 The stream will keep attributes that may have been set by inflateInit2. 835 836 inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source 837 stream state was inconsistent (such as zalloc or state being Z_NULL). 838 */ 839 840 ZEXTERN int ZEXPORT inflateReset2 OF((z_streamp strm, 841 int windowBits)); 842 /* 843 This function is the same as inflateReset, but it also permits changing 844 the wrap and window size requests. The windowBits parameter is 845 interpreted the same as it is for inflateInit2. 846 847 inflateReset2 returns Z_OK if success, or Z_STREAM_ERROR if the source 848 stream state was inconsistent (such as zalloc or state being Z_NULL), or if 849 the windowBits parameter is invalid. 850 */ 851 852 ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm, 853 int bits, 854 int value)); 855 /* 856 This function inserts bits in the inflate input stream. The intent is 857 that this function is used to start inflating at a bit position in the 858 middle of a byte. The provided bits will be used before any bytes are used 859 from next_in. This function should only be used with raw inflate, and 860 should be used before the first inflate() call after inflateInit2() or 861 inflateReset(). bits must be less than or equal to 16, and that many of the 862 least significant bits of value will be inserted in the input. 863 864 If bits is negative, then the input stream bit buffer is emptied. Then 865 inflatePrime() can be called again to put bits in the buffer. This is used 866 to clear out bits leftover after feeding inflate a block description prior 867 to feeding inflate codes. 868 869 inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source 870 stream state was inconsistent. 871 */ 872 873 ZEXTERN long ZEXPORT inflateMark OF((z_streamp strm)); 874 /* 875 This function returns two values, one in the lower 16 bits of the return 876 value, and the other in the remaining upper bits, obtained by shifting the 877 return value down 16 bits. If the upper value is -1 and the lower value is 878 zero, then inflate() is currently decoding information outside of a block. 879 If the upper value is -1 and the lower value is non-zero, then inflate is in 880 the middle of a stored block, with the lower value equaling the number of 881 bytes from the input remaining to copy. If the upper value is not -1, then 882 it is the number of bits back from the current bit position in the input of 883 the code (literal or length/distance pair) currently being processed. In 884 that case the lower value is the number of bytes already emitted for that 885 code. 886 887 A code is being processed if inflate is waiting for more input to complete 888 decoding of the code, or if it has completed decoding but is waiting for 889 more output space to write the literal or match data. 890 891 inflateMark() is used to mark locations in the input data for random 892 access, which may be at bit positions, and to note those cases where the 893 output of a code may span boundaries of random access blocks. The current 894 location in the input stream can be determined from avail_in and data_type 895 as noted in the description for the Z_BLOCK flush parameter for inflate. 896 897 inflateMark returns the value noted above or -1 << 16 if the provided 898 source stream state was inconsistent. 899 */ 900 901 ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm, 902 gz_headerp head)); 903 /* 904 inflateGetHeader() requests that gzip header information be stored in the 905 provided gz_header structure. inflateGetHeader() may be called after 906 inflateInit2() or inflateReset(), and before the first call of inflate(). 907 As inflate() processes the gzip stream, head->done is zero until the header 908 is completed, at which time head->done is set to one. If a zlib stream is 909 being decoded, then head->done is set to -1 to indicate that there will be 910 no gzip header information forthcoming. Note that Z_BLOCK or Z_TREES can be 911 used to force inflate() to return immediately after header processing is 912 complete and before any actual data is decompressed. 913 914 The text, time, xflags, and os fields are filled in with the gzip header 915 contents. hcrc is set to true if there is a header CRC. (The header CRC 916 was valid if done is set to one.) If extra is not Z_NULL, then extra_max 917 contains the maximum number of bytes to write to extra. Once done is true, 918 extra_len contains the actual extra field length, and extra contains the 919 extra field, or that field truncated if extra_max is less than extra_len. 920 If name is not Z_NULL, then up to name_max characters are written there, 921 terminated with a zero unless the length is greater than name_max. If 922 comment is not Z_NULL, then up to comm_max characters are written there, 923 terminated with a zero unless the length is greater than comm_max. When 924 any of extra, name, or comment are not Z_NULL and the respective field is 925 not present in the header, then that field is set to Z_NULL to signal its 926 absence. This allows the use of deflateSetHeader() with the returned 927 structure to duplicate the header. However if those fields are set to 928 allocated memory, then the application will need to save those pointers 929 elsewhere so that they can be eventually freed. 930 931 If inflateGetHeader is not used, then the header information is simply 932 discarded. The header is always checked for validity, including the header 933 CRC if present. inflateReset() will reset the process to discard the header 934 information. The application would need to call inflateGetHeader() again to 935 retrieve the header from the next gzip stream. 936 937 inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source 938 stream state was inconsistent. 939 */ 940 941 /* 942 ZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits, 943 unsigned char FAR *window)); 944 945 Initialize the internal stream state for decompression using inflateBack() 946 calls. The fields zalloc, zfree and opaque in strm must be initialized 947 before the call. If zalloc and zfree are Z_NULL, then the default library- 948 derived memory allocation routines are used. windowBits is the base two 949 logarithm of the window size, in the range 8..15. window is a caller 950 supplied buffer of that size. Except for special applications where it is 951 assured that deflate was used with small window sizes, windowBits must be 15 952 and a 32K byte window must be supplied to be able to decompress general 953 deflate streams. 954 955 See inflateBack() for the usage of these routines. 956 957 inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of 958 the paramaters are invalid, Z_MEM_ERROR if the internal state could not 959 be allocated, or Z_VERSION_ERROR if the version of the library does not 960 match the version of the header file. 961 */ 962 963 typedef unsigned (*in_func) OF((void FAR *, unsigned char FAR * FAR *)); 964 typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned)); 965 966 ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm, 967 in_func in, void FAR *in_desc, 968 out_func out, void FAR *out_desc)); 969 /* 970 inflateBack() does a raw inflate with a single call using a call-back 971 interface for input and output. This is more efficient than inflate() for 972 file i/o applications in that it avoids copying between the output and the 973 sliding window by simply making the window itself the output buffer. This 974 function trusts the application to not change the output buffer passed by 975 the output function, at least until inflateBack() returns. 976 977 inflateBackInit() must be called first to allocate the internal state 978 and to initialize the state with the user-provided window buffer. 979 inflateBack() may then be used multiple times to inflate a complete, raw 980 deflate stream with each call. inflateBackEnd() is then called to free 981 the allocated state. 982 983 A raw deflate stream is one with no zlib or gzip header or trailer. 984 This routine would normally be used in a utility that reads zip or gzip 985 files and writes out uncompressed files. The utility would decode the 986 header and process the trailer on its own, hence this routine expects 987 only the raw deflate stream to decompress. This is different from the 988 normal behavior of inflate(), which expects either a zlib or gzip header and 989 trailer around the deflate stream. 990 991 inflateBack() uses two subroutines supplied by the caller that are then 992 called by inflateBack() for input and output. inflateBack() calls those 993 routines until it reads a complete deflate stream and writes out all of the 994 uncompressed data, or until it encounters an error. The function's 995 parameters and return types are defined above in the in_func and out_func 996 typedefs. inflateBack() will call in(in_desc, &buf) which should return the 997 number of bytes of provided input, and a pointer to that input in buf. If 998 there is no input available, in() must return zero--buf is ignored in that 999 case--and inflateBack() will return a buffer error. inflateBack() will call 1000 out(out_desc, buf, len) to write the uncompressed data buf[0..len-1]. out() 1001 should return zero on success, or non-zero on failure. If out() returns 1002 non-zero, inflateBack() will return with an error. Neither in() nor out() 1003 are permitted to change the contents of the window provided to 1004 inflateBackInit(), which is also the buffer that out() uses to write from. 1005 The length written by out() will be at most the window size. Any non-zero 1006 amount of input may be provided by in(). 1007 1008 For convenience, inflateBack() can be provided input on the first call by 1009 setting strm->next_in and strm->avail_in. If that input is exhausted, then 1010 in() will be called. Therefore strm->next_in must be initialized before 1011 calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called 1012 immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in 1013 must also be initialized, and then if strm->avail_in is not zero, input will 1014 initially be taken from strm->next_in[0 .. strm->avail_in - 1]. 1015 1016 The in_desc and out_desc parameters of inflateBack() is passed as the 1017 first parameter of in() and out() respectively when they are called. These 1018 descriptors can be optionally used to pass any information that the caller- 1019 supplied in() and out() functions need to do their job. 1020 1021 On return, inflateBack() will set strm->next_in and strm->avail_in to 1022 pass back any unused input that was provided by the last in() call. The 1023 return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR 1024 if in() or out() returned an error, Z_DATA_ERROR if there was a format 1025 error in the deflate stream (in which case strm->msg is set to indicate the 1026 nature of the error), or Z_STREAM_ERROR if the stream was not properly 1027 initialized. In the case of Z_BUF_ERROR, an input or output error can be 1028 distinguished using strm->next_in which will be Z_NULL only if in() returned 1029 an error. If strm->next_in is not Z_NULL, then the Z_BUF_ERROR was due to 1030 out() returning non-zero. (in() will always be called before out(), so 1031 strm->next_in is assured to be defined if out() returns non-zero.) Note 1032 that inflateBack() cannot return Z_OK. 1033 */ 1034 1035 ZEXTERN int ZEXPORT inflateBackEnd OF((z_streamp strm)); 1036 /* 1037 All memory allocated by inflateBackInit() is freed. 1038 1039 inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream 1040 state was inconsistent. 1041 */ 1042 1043 ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void)); 1044 /* Return flags indicating compile-time options. 1045 1046 Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other: 1047 1.0: size of uInt 1048 3.2: size of uLong 1049 5.4: size of voidpf (pointer) 1050 7.6: size of z_off_t 1051 1052 Compiler, assembler, and debug options: 1053 8: DEBUG 1054 9: ASMV or ASMINF -- use ASM code 1055 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention 1056 11: 0 (reserved) 1057 1058 One-time table building (smaller code, but not thread-safe if true): 1059 12: BUILDFIXED -- build static block decoding tables when needed 1060 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed 1061 14,15: 0 (reserved) 1062 1063 Library content (indicates missing functionality): 1064 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking 1065 deflate code when not needed) 1066 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect 1067 and decode gzip streams (to avoid linking crc code) 1068 18-19: 0 (reserved) 1069 1070 Operation variations (changes in library functionality): 1071 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate 1072 21: FASTEST -- deflate algorithm with only one, lowest compression level 1073 22,23: 0 (reserved) 1074 1075 The sprintf variant used by gzprintf (zero is best): 1076 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format 1077 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure! 1078 26: 0 = returns value, 1 = void -- 1 means inferred string length returned 1079 1080 Remainder: 1081 27-31: 0 (reserved) 1082 */ 1083 1084 1085 /* utility functions */ 1086 1087 /* 1088 The following utility functions are implemented on top of the 1089 basic stream-oriented functions. To simplify the interface, some 1090 default options are assumed (compression level and memory usage, 1091 standard memory allocation functions). The source code of these 1092 utility functions can easily be modified if you need special options. 1093 */ 1094 1095 ZEXTERN int ZEXPORT compress OF((Bytef *dest, uLongf *destLen, 1096 const Bytef *source, uLong sourceLen)); 1097 /* 1098 Compresses the source buffer into the destination buffer. sourceLen is 1099 the byte length of the source buffer. Upon entry, destLen is the total 1100 size of the destination buffer, which must be at least the value returned 1101 by compressBound(sourceLen). Upon exit, destLen is the actual size of the 1102 compressed buffer. 1103 This function can be used to compress a whole file at once if the 1104 input file is mmap'ed. 1105 compress returns Z_OK if success, Z_MEM_ERROR if there was not 1106 enough memory, Z_BUF_ERROR if there was not enough room in the output 1107 buffer. 1108 */ 1109 1110 ZEXTERN int ZEXPORT compress2 OF((Bytef *dest, uLongf *destLen, 1111 const Bytef *source, uLong sourceLen, 1112 int level)); 1113 /* 1114 Compresses the source buffer into the destination buffer. The level 1115 parameter has the same meaning as in deflateInit. sourceLen is the byte 1116 length of the source buffer. Upon entry, destLen is the total size of the 1117 destination buffer, which must be at least the value returned by 1118 compressBound(sourceLen). Upon exit, destLen is the actual size of the 1119 compressed buffer. 1120 1121 compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 1122 memory, Z_BUF_ERROR if there was not enough room in the output buffer, 1123 Z_STREAM_ERROR if the level parameter is invalid. 1124 */ 1125 1126 ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen)); 1127 /* 1128 compressBound() returns an upper bound on the compressed size after 1129 compress() or compress2() on sourceLen bytes. It would be used before 1130 a compress() or compress2() call to allocate the destination buffer. 1131 */ 1132 1133 ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen, 1134 const Bytef *source, uLong sourceLen)); 1135 /* 1136 Decompresses the source buffer into the destination buffer. sourceLen is 1137 the byte length of the source buffer. Upon entry, destLen is the total 1138 size of the destination buffer, which must be large enough to hold the 1139 entire uncompressed data. (The size of the uncompressed data must have 1140 been saved previously by the compressor and transmitted to the decompressor 1141 by some mechanism outside the scope of this compression library.) 1142 Upon exit, destLen is the actual size of the uncompressed buffer. 1143 This function can be used to decompress a whole file at once if the 1144 input file is mmap'ed. 1145 1146 uncompress returns Z_OK if success, Z_MEM_ERROR if there was not 1147 enough memory, Z_BUF_ERROR if there was not enough room in the output 1148 buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete. 1149 */ 1150 1151 1152 typedef voidp gzFile; 1153 1154 /* 1155 ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode)); 1156 1157 Opens a gzip (.gz) file for reading or writing. The mode parameter 1158 is as in fopen ("rb" or "wb") but can also include a compression level 1159 ("wb9") or a strategy: 'f' for filtered data as in "wb6f", 'h' for 1160 Huffman only compression as in "wb1h", or 'R' for run-length encoding 1161 as in "wb1R". (See the description of deflateInit2 for more information 1162 about the strategy parameter.) 1163 1164 gzopen can be used to read a file which is not in gzip format; in this 1165 case gzread will directly read from the file without decompression. 1166 1167 gzopen returns NULL if the file could not be opened or if there was 1168 insufficient memory to allocate the (de)compression state; errno 1169 can be checked to distinguish the two cases (if errno is zero, the 1170 zlib error is Z_MEM_ERROR). */ 1171 1172 ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode)); 1173 /* 1174 gzdopen() associates a gzFile with the file descriptor fd. File 1175 descriptors are obtained from calls like open, dup, creat, pipe or 1176 fileno (in the file has been previously opened with fopen). 1177 The mode parameter is as in gzopen. 1178 The next call of gzclose on the returned gzFile will also close the 1179 file descriptor fd, just like fclose(fdopen(fd), mode) closes the file 1180 descriptor fd. If you want to keep fd open, use gzdopen(dup(fd), mode). 1181 gzdopen returns NULL if there was insufficient memory to allocate 1182 the (de)compression state. 1183 */ 1184 1185 ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy)); 1186 /* 1187 Dynamically update the compression level or strategy. See the description 1188 of deflateInit2 for the meaning of these parameters. 1189 gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not 1190 opened for writing. 1191 */ 1192 1193 ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len)); 1194 /* 1195 Reads the given number of uncompressed bytes from the compressed file. 1196 If the input file was not in gzip format, gzread copies the given number 1197 of bytes into the buffer. 1198 gzread returns the number of uncompressed bytes actually read (0 for 1199 end of file, -1 for error). */ 1200 1201 ZEXTERN int ZEXPORT gzwrite OF((gzFile file, 1202 voidpc buf, unsigned len)); 1203 /* 1204 Writes the given number of uncompressed bytes into the compressed file. 1205 gzwrite returns the number of uncompressed bytes actually written 1206 (0 in case of error). 1207 */ 1208 1209 ZEXTERN int ZEXPORTVA gzprintf OF((gzFile file, const char *format, ...)); 1210 /* 1211 Converts, formats, and writes the args to the compressed file under 1212 control of the format string, as in fprintf. gzprintf returns the number of 1213 uncompressed bytes actually written (0 in case of error). The number of 1214 uncompressed bytes written is limited to 4095. The caller should assure that 1215 this limit is not exceeded. If it is exceeded, then gzprintf() will return 1216 return an error (0) with nothing written. In this case, there may also be a 1217 buffer overflow with unpredictable consequences, which is possible only if 1218 zlib was compiled with the insecure functions sprintf() or vsprintf() 1219 because the secure snprintf() or vsnprintf() functions were not available. 1220 */ 1221 1222 ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s)); 1223 /* 1224 Writes the given null-terminated string to the compressed file, excluding 1225 the terminating null character. 1226 gzputs returns the number of characters written, or -1 in case of error. 1227 */ 1228 1229 ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len)); 1230 /* 1231 Reads bytes from the compressed file until len-1 characters are read, or 1232 a newline character is read and transferred to buf, or an end-of-file 1233 condition is encountered. The string is then terminated with a null 1234 character. 1235 gzgets returns buf, or Z_NULL in case of error. 1236 */ 1237 1238 ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c)); 1239 /* 1240 Writes c, converted to an unsigned char, into the compressed file. 1241 gzputc returns the value that was written, or -1 in case of error. 1242 */ 1243 1244 ZEXTERN int ZEXPORT gzgetc OF((gzFile file)); 1245 /* 1246 Reads one byte from the compressed file. gzgetc returns this byte 1247 or -1 in case of end of file or error. 1248 */ 1249 1250 ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file)); 1251 /* 1252 Push one character back onto the stream to be read again later. 1253 Only one character of push-back is allowed. gzungetc() returns the 1254 character pushed, or -1 on failure. gzungetc() will fail if a 1255 character has been pushed but not read yet, or if c is -1. The pushed 1256 character will be discarded if the stream is repositioned with gzseek() 1257 or gzrewind(). 1258 */ 1259 1260 ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush)); 1261 /* 1262 Flushes all pending output into the compressed file. The parameter 1263 flush is as in the deflate() function. The return value is the zlib 1264 error number (see function gzerror below). gzflush returns Z_OK if 1265 the flush parameter is Z_FINISH and all output could be flushed. 1266 gzflush should be called only when strictly necessary because it can 1267 degrade compression. 1268 */ 1269 1270 /* 1271 ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file, 1272 z_off_t offset, int whence)); 1273 1274 Sets the starting position for the next gzread or gzwrite on the 1275 given compressed file. The offset represents a number of bytes in the 1276 uncompressed data stream. The whence parameter is defined as in lseek(2); 1277 the value SEEK_END is not supported. 1278 If the file is opened for reading, this function is emulated but can be 1279 extremely slow. If the file is opened for writing, only forward seeks are 1280 supported; gzseek then compresses a sequence of zeroes up to the new 1281 starting position. 1282 1283 gzseek returns the resulting offset location as measured in bytes from 1284 the beginning of the uncompressed stream, or -1 in case of error, in 1285 particular if the file is opened for writing and the new starting position 1286 would be before the current position. 1287 */ 1288 1289 ZEXTERN int ZEXPORT gzrewind OF((gzFile file)); 1290 /* 1291 Rewinds the given file. This function is supported only for reading. 1292 1293 gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET) 1294 */ 1295 1296 /* 1297 ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file)); 1298 1299 Returns the starting position for the next gzread or gzwrite on the 1300 given compressed file. This position represents a number of bytes in the 1301 uncompressed data stream. 1302 1303 gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR) 1304 */ 1305 1306 ZEXTERN int ZEXPORT gzeof OF((gzFile file)); 1307 /* 1308 Returns 1 when EOF has previously been detected reading the given 1309 input stream, otherwise zero. 1310 */ 1311 1312 ZEXTERN int ZEXPORT gzdirect OF((gzFile file)); 1313 /* 1314 Returns 1 if file is being read directly without decompression, otherwise 1315 zero. 1316 */ 1317 1318 ZEXTERN int ZEXPORT gzclose OF((gzFile file)); 1319 /* 1320 Flushes all pending output if necessary, closes the compressed file 1321 and deallocates all the (de)compression state. The return value is the zlib 1322 error number. Note that once file is close, you cannot call gzerror with 1323 file, since its structures have been deallocated. 1324 */ 1325 1326 ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum)); 1327 /* 1328 Returns the error message for the last error which occurred on the 1329 given compressed file. errnum is set to zlib error number. If an 1330 error occurred in the file system and not in the compression library, 1331 errnum is set to Z_ERRNO and the application may consult errno 1332 to get the exact error code. 1333 1334 The application must not modify the returned string and future calls to 1335 this function may invalidate the returned string. 1336 */ 1337 1338 ZEXTERN void ZEXPORT gzclearerr OF((gzFile file)); 1339 /* 1340 Clears the error and end-of-file flags for file. This is analogous to the 1341 clearerr() function in stdio. This is useful for continuing to read a gzip 1342 file that is being written concurrently. 1343 */ 1344 1345 /* checksum functions */ 1346 1347 /* 1348 These functions are not related to compression but are exported 1349 anyway because they might be useful in applications using the 1350 compression library. 1351 */ 1352 1353 ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len)); 1354 /* 1355 Update a running Adler-32 checksum with the bytes buf[0..len-1] and 1356 return the updated checksum. If buf is Z_NULL, this function returns 1357 the required initial value for the checksum. 1358 An Adler-32 checksum is almost as reliable as a CRC32 but can be computed 1359 much faster. Usage example: 1360 1361 uLong adler = adler32(0L, Z_NULL, 0); 1362 1363 while (read_buffer(buffer, length) != EOF) { 1364 adler = adler32(adler, buffer, length); 1365 } 1366 if (adler != original_adler) error(); 1367 */ 1368 1369 /* 1370 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong adler1, uLong adler2, 1371 z_off_t len2)); 1372 1373 Combine two Adler-32 checksums into one. For two sequences of bytes, seq1 1374 and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for 1375 each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of 1376 seq1 and seq2 concatenated, requiring only adler1, adler2, and len2. 1377 */ 1378 1379 ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len)); 1380 /* 1381 Update a running CRC-32 with the bytes buf[0..len-1] and return the 1382 updated CRC-32. If buf is Z_NULL, this function returns the required initial 1383 value for the for the crc. Pre- and post-conditioning (one's complement) is 1384 performed within this function so it shouldn't be done by the application. 1385 Usage example: 1386 1387 uLong crc = crc32(0L, Z_NULL, 0); 1388 1389 while (read_buffer(buffer, length) != EOF) { 1390 crc = crc32(crc, buffer, length); 1391 } 1392 if (crc != original_crc) error(); 1393 */ 1394 1395 /* 1396 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2)); 1397 1398 Combine two CRC-32 check values into one. For two sequences of bytes, 1399 seq1 and seq2 with lengths len1 and len2, CRC-32 check values were 1400 calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32 1401 check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and 1402 len2. 1403 */ 1404 1405 1406 /* various hacks, don't look :) */ 1407 1408 /* deflateInit and inflateInit are macros to allow checking the zlib version 1409 * and the compiler's view of z_stream: 1410 */ 1411 ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level, 1412 const char *version, int stream_size)); 1413 ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm, 1414 const char *version, int stream_size)); 1415 ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method, 1416 int windowBits, int memLevel, 1417 int strategy, const char *version, 1418 int stream_size)); 1419 ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits, 1420 const char *version, int stream_size)); 1421 ZEXTERN int ZEXPORT inflateBackInit_ OF((z_streamp strm, int windowBits, 1422 unsigned char FAR *window, 1423 const char *version, 1424 int stream_size)); 1425 #define deflateInit(strm, level) \ 1426 deflateInit_((strm), (level), ZLIB_VERSION, sizeof(z_stream)) 1427 #define inflateInit(strm) \ 1428 inflateInit_((strm), ZLIB_VERSION, sizeof(z_stream)) 1429 #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \ 1430 deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\ 1431 (strategy), ZLIB_VERSION, sizeof(z_stream)) 1432 #define inflateInit2(strm, windowBits) \ 1433 inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream)) 1434 #define inflateBackInit(strm, windowBits, window) \ 1435 inflateBackInit_((strm), (windowBits), (window), \ 1436 ZLIB_VERSION, sizeof(z_stream)) 1437 1438 #if defined(_LARGEFILE64_SOURCE) 1439 #define z_off64_t off64_t 1440 #else 1441 #if _FILE_OFFSET_BITS == 64 1442 #define z_off64_t off_t 1443 #endif 1444 #endif 1445 1446 #if defined(_LARGEFILE64_SOURCE) || _FILE_OFFSET_BITS == 64 1447 ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *)); 1448 ZEXTERN z_off64_t ZEXPORT gzseek64 OF((gzFile, z_off64_t, int)); 1449 ZEXTERN z_off64_t ZEXPORT gztell64 OF((gzFile)); 1450 ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off64_t)); 1451 ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off64_t)); 1452 #endif 1453 1454 #if !defined(ZLIB_INTERNAL) && _FILE_OFFSET_BITS == 64 1455 # define gzopen gzopen64 1456 # define gzseek gzseek64 1457 # define gztell gztell64 1458 # define adler32_combine adler32_combine64 1459 # define crc32_combine crc32_combine64 1460 # ifndef _LARGEFILE64_SOURCE 1461 ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *)); 1462 ZEXTERN off_t ZEXPORT gzseek64 OF((gzFile, off_t, int)); 1463 ZEXTERN off_t ZEXPORT gztell64 OF((gzFile)); 1464 ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, off_t)); 1465 ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, off_t)); 1466 # endif 1467 #else 1468 ZEXTERN gzFile ZEXPORT gzopen OF((const char *, const char *)); 1469 ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile, z_off_t, int)); 1470 ZEXTERN z_off_t ZEXPORT gztell OF((gzFile)); 1471 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t)); 1472 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t)); 1473 #endif 1474 1475 #if !defined(ZUTIL_H) && !defined(NO_DUMMY_DECL) 1476 struct internal_state {int dummy;}; /* hack for buggy compilers */ 1477 #endif 1478 1479 ZEXTERN const char * ZEXPORT zError OF((int)); 1480 ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp)); 1481 ZEXTERN const uLongf * ZEXPORT get_crc_table OF((void)); 1482 ZEXTERN int ZEXPORT inflateUndermine OF((z_streamp, int)); 1483 1484 #ifdef __cplusplus 1485 } 1486 #endif 1487 1488 #endif /* ZLIB_H */ 1489