1 /* zlib.h -- interface of the 'zlib' general purpose compression library 2 version 1.2.6, January 29th, 2012 3 4 Copyright (C) 1995-2012 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://tools.ietf.org/html/rfc1950 28 (zlib format), rfc1951 (deflate format) and rfc1952 (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 "1.2.6" 41 #define ZLIB_VERNUM 0x1260 42 #define ZLIB_VER_MAJOR 1 43 #define ZLIB_VER_MINOR 2 44 #define ZLIB_VER_REVISION 6 45 #define ZLIB_VER_SUBREVISION 0 46 47 /* 48 The 'zlib' compression library provides in-memory compression and 49 decompression functions, including integrity checks of the uncompressed data. 50 This version of the library supports only one compression method (deflation) 51 but other algorithms will be added later and will have the same stream 52 interface. 53 54 Compression can be done in a single step if the buffers are large enough, 55 or can be done by repeated calls of the compression function. In the latter 56 case, the 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 crash 77 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 z_const Bytef *next_in; /* next input byte */ 87 uInt avail_in; /* number of bytes available at next_in */ 88 uLong total_in; /* total number 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 number of bytes output so far */ 93 94 z_const 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 dropped 133 to zero. It must update next_out and avail_out when avail_out has dropped 134 to zero. The application must initialize zalloc, zfree and opaque before 135 calling the init function. All other fields are set by the compression 136 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 if 149 the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, pointers 150 returned by zalloc for objects of exactly 65536 bytes *must* have their 151 offset normalized to zero. The default allocation function provided by this 152 library ensures this (see zutil.c). To reduce memory requirements and avoid 153 any allocation of 64K objects, at the expense of compression ratio, compile 154 the library with -DMAX_WBITS=14 (see zconf.h). 155 156 The fields total_in and total_out can be used for statistics or progress 157 reports. After compression, total_in holds the total size of the 158 uncompressed data and may be saved for use in the decompressor (particularly 159 if the decompressor wants to decompress everything in a single step). 160 */ 161 162 /* constants */ 163 164 #define Z_NO_FLUSH 0 165 #define Z_PARTIAL_FLUSH 1 166 #define Z_SYNC_FLUSH 2 167 #define Z_FULL_FLUSH 3 168 #define Z_FINISH 4 169 #define Z_BLOCK 5 170 #define Z_TREES 6 171 /* Allowed flush values; see deflate() and inflate() below for details */ 172 173 #define Z_OK 0 174 #define Z_STREAM_END 1 175 #define Z_NEED_DICT 2 176 #define Z_ERRNO (-1) 177 #define Z_STREAM_ERROR (-2) 178 #define Z_DATA_ERROR (-3) 179 #define Z_MEM_ERROR (-4) 180 #define Z_BUF_ERROR (-5) 181 #define Z_VERSION_ERROR (-6) 182 /* Return codes for the compression/decompression functions. Negative values 183 * are errors, positive values are used for special but normal events. 184 */ 185 186 #define Z_NO_COMPRESSION 0 187 #define Z_BEST_SPEED 1 188 #define Z_BEST_COMPRESSION 9 189 #define Z_DEFAULT_COMPRESSION (-1) 190 /* compression levels */ 191 192 #define Z_FILTERED 1 193 #define Z_HUFFMAN_ONLY 2 194 #define Z_RLE 3 195 #define Z_FIXED 4 196 #define Z_DEFAULT_STRATEGY 0 197 /* compression strategy; see deflateInit2() below for details */ 198 199 #define Z_BINARY 0 200 #define Z_TEXT 1 201 #define Z_ASCII Z_TEXT /* for compatibility with 1.2.2 and earlier */ 202 #define Z_UNKNOWN 2 203 /* Possible values of the data_type field (though see inflate()) */ 204 205 #define Z_DEFLATED 8 206 /* The deflate compression method (the only one supported in this version) */ 207 208 #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */ 209 210 #define zlib_version zlibVersion() 211 /* for compatibility with versions < 1.0.2 */ 212 213 214 /* 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 not 219 compatible with the zlib.h header file used by the application. This check 220 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. If 228 zalloc and zfree are set to Z_NULL, deflateInit updates them to use default 229 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 all 233 (the input data is simply copied a block at a time). Z_DEFAULT_COMPRESSION 234 requests a default compromise between speed and compression (currently 235 equivalent to level 6). 236 237 deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough 238 memory, Z_STREAM_ERROR if level is not a valid compression level, or 239 Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible 240 with the version assumed by the caller (ZLIB_VERSION). msg is set to null 241 if there is no error message. deflateInit does not perform any compression: 242 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 250 some 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). Some 265 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 more 269 output, and updating avail_in or avail_out accordingly; avail_out should 270 never be zero before the call. The application can consume the compressed 271 output when it wants, for example when the output buffer is full (avail_out 272 == 0), or after each call of deflate(). If deflate returns Z_OK and with 273 zero avail_out, it must be called again after making room in the output 274 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 283 particular avail_in is zero after the call if enough output space has been 284 provided before the call.) Flushing may degrade compression for some 285 compression algorithms and so it should be used only when necessary. This 286 completes the current deflate block and follows it with an empty stored block 287 that is three bits plus filler bits to the next byte, followed by four bytes 288 (00 00 ff ff). 289 290 If flush is set to Z_PARTIAL_FLUSH, all pending output is flushed to the 291 output buffer, but the output is not aligned to a byte boundary. All of the 292 input data so far will be available to the decompressor, as for Z_SYNC_FLUSH. 293 This completes the current deflate block and follows it with an empty fixed 294 codes block that is 10 bits long. This assures that enough bytes are output 295 in order for the decompressor to finish the block before the empty fixed code 296 block. 297 298 If flush is set to Z_BLOCK, a deflate block is completed and emitted, as 299 for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to 300 seven bits of the current block are held to be written as the next byte after 301 the next deflate block is completed. In this case, the decompressor may not 302 be provided enough bits at this point in order to complete decompression of 303 the data provided so far to the compressor. It may need to wait for the next 304 block to be emitted. This is for advanced applications that need to control 305 the emission of deflate blocks. 306 307 If flush is set to Z_FULL_FLUSH, all output is flushed as with 308 Z_SYNC_FLUSH, and the compression state is reset so that decompression can 309 restart from this point if previous compressed data has been damaged or if 310 random access is desired. Using Z_FULL_FLUSH too often can seriously degrade 311 compression. 312 313 If deflate returns with avail_out == 0, this function must be called again 314 with the same value of the flush parameter and more output space (updated 315 avail_out), until the flush is complete (deflate returns with non-zero 316 avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that 317 avail_out is greater than six to avoid repeated flush markers due to 318 avail_out == 0 on return. 319 320 If the parameter flush is set to Z_FINISH, pending input is processed, 321 pending output is flushed and deflate returns with Z_STREAM_END if there was 322 enough output space; if deflate returns with Z_OK, this function must be 323 called again with Z_FINISH and more output space (updated avail_out) but no 324 more input data, until it returns with Z_STREAM_END or an error. After 325 deflate has returned Z_STREAM_END, the only possible operations on the stream 326 are deflateReset or deflateEnd. 327 328 Z_FINISH can be used immediately after deflateInit if all the compression 329 is to be done in a single step. In this case, avail_out must be at least the 330 value returned by deflateBound (see below). Then deflate is guaranteed to 331 return Z_STREAM_END. If not enough output space is provided, deflate will 332 not return Z_STREAM_END, and it must be called again as described above. 333 334 deflate() sets strm->adler to the adler32 checksum of all input read 335 so far (that is, total_in bytes). 336 337 deflate() may update strm->data_type if it can make a good guess about 338 the input data type (Z_BINARY or Z_TEXT). In doubt, the data is considered 339 binary. This field is only for information purposes and does not affect the 340 compression algorithm in any manner. 341 342 deflate() returns Z_OK if some progress has been made (more input 343 processed or more output produced), Z_STREAM_END if all input has been 344 consumed and all output has been produced (only when flush is set to 345 Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example 346 if next_in or next_out was Z_NULL), Z_BUF_ERROR if no progress is possible 347 (for example avail_in or avail_out was zero). Note that Z_BUF_ERROR is not 348 fatal, and deflate() can be called again with more input and more output 349 space to continue compressing. 350 */ 351 352 353 ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm)); 354 /* 355 All dynamically allocated data structures for this stream are freed. 356 This function discards any unprocessed input and does not flush any pending 357 output. 358 359 deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the 360 stream state was inconsistent, Z_DATA_ERROR if the stream was freed 361 prematurely (some input or output was discarded). In the error case, msg 362 may be set but then points to a static string (which must not be 363 deallocated). 364 */ 365 366 367 /* 368 ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm)); 369 370 Initializes the internal stream state for decompression. The fields 371 next_in, avail_in, zalloc, zfree and opaque must be initialized before by 372 the caller. If next_in is not Z_NULL and avail_in is large enough (the 373 exact value depends on the compression method), inflateInit determines the 374 compression method from the zlib header and allocates all data structures 375 accordingly; otherwise the allocation will be deferred to the first call of 376 inflate. If zalloc and zfree are set to Z_NULL, inflateInit updates them to 377 use default allocation functions. 378 379 inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough 380 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the 381 version assumed by the caller, or Z_STREAM_ERROR if the parameters are 382 invalid, such as a null pointer to the structure. msg is set to null if 383 there is no error message. inflateInit does not perform any decompression 384 apart from possibly reading the zlib header if present: actual decompression 385 will be done by inflate(). (So next_in and avail_in may be modified, but 386 next_out and avail_out are unused and unchanged.) The current implementation 387 of inflateInit() does not process any header information -- that is deferred 388 until inflate() is called. 389 */ 390 391 392 ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush)); 393 /* 394 inflate decompresses as much data as possible, and stops when the input 395 buffer becomes empty or the output buffer becomes full. It may introduce 396 some output latency (reading input without producing any output) except when 397 forced to flush. 398 399 The detailed semantics are as follows. inflate performs one or both of the 400 following actions: 401 402 - Decompress more input starting at next_in and update next_in and avail_in 403 accordingly. If not all input can be processed (because there is not 404 enough room in the output buffer), next_in is updated and processing will 405 resume at this point for the next call of inflate(). 406 407 - Provide more output starting at next_out and update next_out and avail_out 408 accordingly. inflate() provides as much output as possible, until there is 409 no more input data or no more space in the output buffer (see below about 410 the flush parameter). 411 412 Before the call of inflate(), the application should ensure that at least 413 one of the actions is possible, by providing more input and/or consuming more 414 output, and updating the next_* and avail_* values accordingly. The 415 application can consume the uncompressed output when it wants, for example 416 when the output buffer is full (avail_out == 0), or after each call of 417 inflate(). If inflate returns Z_OK and with zero avail_out, it must be 418 called again after making room in the output buffer because there might be 419 more output pending. 420 421 The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, Z_FINISH, 422 Z_BLOCK, or Z_TREES. Z_SYNC_FLUSH requests that inflate() flush as much 423 output as possible to the output buffer. Z_BLOCK requests that inflate() 424 stop if and when it gets to the next deflate block boundary. When decoding 425 the zlib or gzip format, this will cause inflate() to return immediately 426 after the header and before the first block. When doing a raw inflate, 427 inflate() will go ahead and process the first block, and will return when it 428 gets to the end of that block, or when it runs out of data. 429 430 The Z_BLOCK option assists in appending to or combining deflate streams. 431 Also to assist in this, on return inflate() will set strm->data_type to the 432 number of unused bits in the last byte taken from strm->next_in, plus 64 if 433 inflate() is currently decoding the last block in the deflate stream, plus 434 128 if inflate() returned immediately after decoding an end-of-block code or 435 decoding the complete header up to just before the first byte of the deflate 436 stream. The end-of-block will not be indicated until all of the uncompressed 437 data from that block has been written to strm->next_out. The number of 438 unused bits may in general be greater than seven, except when bit 7 of 439 data_type is set, in which case the number of unused bits will be less than 440 eight. data_type is set as noted here every time inflate() returns for all 441 flush options, and so can be used to determine the amount of currently 442 consumed input in bits. 443 444 The Z_TREES option behaves as Z_BLOCK does, but it also returns when the 445 end of each deflate block header is reached, before any actual data in that 446 block is decoded. This allows the caller to determine the length of the 447 deflate block header for later use in random access within a deflate block. 448 256 is added to the value of strm->data_type when inflate() returns 449 immediately after reaching the end of the deflate block header. 450 451 inflate() should normally be called until it returns Z_STREAM_END or an 452 error. However if all decompression is to be performed in a single step (a 453 single call of inflate), the parameter flush should be set to Z_FINISH. In 454 this case all pending input is processed and all pending output is flushed; 455 avail_out must be large enough to hold all the uncompressed data. (The size 456 of the uncompressed data may have been saved by the compressor for this 457 purpose.) The next operation on this stream must be inflateEnd to deallocate 458 the decompression state. The use of Z_FINISH is not required to perform an 459 inflation in one step. However it may be used to inform inflate that a 460 faster approach can be used for the single inflate() call. Z_FINISH also 461 informs inflate to not maintain a sliding window if the stream completes, 462 which reduces inflate's memory footprint. 463 464 In this implementation, inflate() always flushes as much output as 465 possible to the output buffer, and always uses the faster approach on the 466 first call. So the effects of the flush parameter in this implementation are 467 on the return value of inflate() as noted below, when inflate() returns early 468 when Z_BLOCK or Z_TREES is used, and when inflate() avoids the allocation of 469 memory for a sliding window when Z_FINISH is used. 470 471 If a preset dictionary is needed after this call (see inflateSetDictionary 472 below), inflate sets strm->adler to the Adler-32 checksum of the dictionary 473 chosen by the compressor and returns Z_NEED_DICT; otherwise it sets 474 strm->adler to the Adler-32 checksum of all output produced so far (that is, 475 total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described 476 below. At the end of the stream, inflate() checks that its computed adler32 477 checksum is equal to that saved by the compressor and returns Z_STREAM_END 478 only if the checksum is correct. 479 480 inflate() can decompress and check either zlib-wrapped or gzip-wrapped 481 deflate data. The header type is detected automatically, if requested when 482 initializing with inflateInit2(). Any information contained in the gzip 483 header is not retained, so applications that need that information should 484 instead use raw inflate, see inflateInit2() below, or inflateBack() and 485 perform their own processing of the gzip header and trailer. When processing 486 gzip-wrapped deflate data, strm->adler32 is set to the CRC-32 of the output 487 producted so far. The CRC-32 is checked against the gzip trailer. 488 489 inflate() returns Z_OK if some progress has been made (more input processed 490 or more output produced), Z_STREAM_END if the end of the compressed data has 491 been reached and all uncompressed output has been produced, Z_NEED_DICT if a 492 preset dictionary is needed at this point, Z_DATA_ERROR if the input data was 493 corrupted (input stream not conforming to the zlib format or incorrect check 494 value), Z_STREAM_ERROR if the stream structure was inconsistent (for example 495 next_in or next_out was Z_NULL), Z_MEM_ERROR if there was not enough memory, 496 Z_BUF_ERROR if no progress is possible or if there was not enough room in the 497 output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and 498 inflate() can be called again with more input and more output space to 499 continue decompressing. If Z_DATA_ERROR is returned, the application may 500 then call inflateSync() to look for a good compression block if a partial 501 recovery of the data is desired. 502 */ 503 504 505 ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm)); 506 /* 507 All dynamically allocated data structures for this stream are freed. 508 This function discards any unprocessed input and does not flush any pending 509 output. 510 511 inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state 512 was inconsistent. In the error case, msg may be set but then points to a 513 static string (which must not be deallocated). 514 */ 515 516 517 /* Advanced functions */ 518 519 /* 520 The following functions are needed only in some special applications. 521 */ 522 523 /* 524 ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm, 525 int level, 526 int method, 527 int windowBits, 528 int memLevel, 529 int strategy)); 530 531 This is another version of deflateInit with more compression options. The 532 fields next_in, zalloc, zfree and opaque must be initialized before by the 533 caller. 534 535 The method parameter is the compression method. It must be Z_DEFLATED in 536 this version of the library. 537 538 The windowBits parameter is the base two logarithm of the window size 539 (the size of the history buffer). It should be in the range 8..15 for this 540 version of the library. Larger values of this parameter result in better 541 compression at the expense of memory usage. The default value is 15 if 542 deflateInit is used instead. 543 544 windowBits can also be -8..-15 for raw deflate. In this case, -windowBits 545 determines the window size. deflate() will then generate raw deflate data 546 with no zlib header or trailer, and will not compute an adler32 check value. 547 548 windowBits can also be greater than 15 for optional gzip encoding. Add 549 16 to windowBits to write a simple gzip header and trailer around the 550 compressed data instead of a zlib wrapper. The gzip header will have no 551 file name, no extra data, no comment, no modification time (set to zero), no 552 header crc, and the operating system will be set to 255 (unknown). If a 553 gzip stream is being written, strm->adler is a crc32 instead of an adler32. 554 555 The memLevel parameter specifies how much memory should be allocated 556 for the internal compression state. memLevel=1 uses minimum memory but is 557 slow and reduces compression ratio; memLevel=9 uses maximum memory for 558 optimal speed. The default value is 8. See zconf.h for total memory usage 559 as a function of windowBits and memLevel. 560 561 The strategy parameter is used to tune the compression algorithm. Use the 562 value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a 563 filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no 564 string match), or Z_RLE to limit match distances to one (run-length 565 encoding). Filtered data consists mostly of small values with a somewhat 566 random distribution. In this case, the compression algorithm is tuned to 567 compress them better. The effect of Z_FILTERED is to force more Huffman 568 coding and less string matching; it is somewhat intermediate between 569 Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as 570 fast as Z_HUFFMAN_ONLY, but give better compression for PNG image data. The 571 strategy parameter only affects the compression ratio but not the 572 correctness of the compressed output even if it is not set appropriately. 573 Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler 574 decoder for special applications. 575 576 deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 577 memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid 578 method), or Z_VERSION_ERROR if the zlib library version (zlib_version) is 579 incompatible with the version assumed by the caller (ZLIB_VERSION). msg is 580 set to null if there is no error message. deflateInit2 does not perform any 581 compression: this will be done by deflate(). 582 */ 583 584 ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm, 585 const Bytef *dictionary, 586 uInt dictLength)); 587 /* 588 Initializes the compression dictionary from the given byte sequence 589 without producing any compressed output. When using the zlib format, this 590 function must be called immediately after deflateInit, deflateInit2 or 591 deflateReset, and before any call of deflate. When doing raw deflate, this 592 function must be called either before any call of deflate, or immediately 593 after the completion of a deflate block, i.e. after all input has been 594 consumed and all output has been delivered when using any of the flush 595 options Z_BLOCK, Z_PARTIAL_FLUSH, Z_SYNC_FLUSH, or Z_FULL_FLUSH. The 596 compressor and decompressor must use exactly the same dictionary (see 597 inflateSetDictionary). 598 599 The dictionary should consist of strings (byte sequences) that are likely 600 to be encountered later in the data to be compressed, with the most commonly 601 used strings preferably put towards the end of the dictionary. Using a 602 dictionary is most useful when the data to be compressed is short and can be 603 predicted with good accuracy; the data can then be compressed better than 604 with the default empty dictionary. 605 606 Depending on the size of the compression data structures selected by 607 deflateInit or deflateInit2, a part of the dictionary may in effect be 608 discarded, for example if the dictionary is larger than the window size 609 provided in deflateInit or deflateInit2. Thus the strings most likely to be 610 useful should be put at the end of the dictionary, not at the front. In 611 addition, the current implementation of deflate will use at most the window 612 size minus 262 bytes of the provided dictionary. 613 614 Upon return of this function, strm->adler is set to the adler32 value 615 of the dictionary; the decompressor may later use this value to determine 616 which dictionary has been used by the compressor. (The adler32 value 617 applies to the whole dictionary even if only a subset of the dictionary is 618 actually used by the compressor.) If a raw deflate was requested, then the 619 adler32 value is not computed and strm->adler is not set. 620 621 deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a 622 parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is 623 inconsistent (for example if deflate has already been called for this stream 624 or if not at a block boundary for raw deflate). deflateSetDictionary does 625 not perform any compression: this will be done by deflate(). 626 */ 627 628 ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest, 629 z_streamp source)); 630 /* 631 Sets the destination stream as a complete copy of the source stream. 632 633 This function can be useful when several compression strategies will be 634 tried, for example when there are several ways of pre-processing the input 635 data with a filter. The streams that will be discarded should then be freed 636 by calling deflateEnd. Note that deflateCopy duplicates the internal 637 compression state which can be quite large, so this strategy is slow and can 638 consume lots of memory. 639 640 deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not 641 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent 642 (such as zalloc being Z_NULL). msg is left unchanged in both source and 643 destination. 644 */ 645 646 ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm)); 647 /* 648 This function is equivalent to deflateEnd followed by deflateInit, 649 but does not free and reallocate all the internal compression state. The 650 stream will keep the same compression level and any other attributes that 651 may have been set by deflateInit2. 652 653 deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source 654 stream state was inconsistent (such as zalloc or state being Z_NULL). 655 */ 656 657 ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm, 658 int level, 659 int strategy)); 660 /* 661 Dynamically update the compression level and compression strategy. The 662 interpretation of level and strategy is as in deflateInit2. This can be 663 used to switch between compression and straight copy of the input data, or 664 to switch to a different kind of input data requiring a different strategy. 665 If the compression level is changed, the input available so far is 666 compressed with the old level (and may be flushed); the new level will take 667 effect only at the next call of deflate(). 668 669 Before the call of deflateParams, the stream state must be set as for 670 a call of deflate(), since the currently available input may have to be 671 compressed and flushed. In particular, strm->avail_out must be non-zero. 672 673 deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source 674 stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR if 675 strm->avail_out was zero. 676 */ 677 678 ZEXTERN int ZEXPORT deflateTune OF((z_streamp strm, 679 int good_length, 680 int max_lazy, 681 int nice_length, 682 int max_chain)); 683 /* 684 Fine tune deflate's internal compression parameters. This should only be 685 used by someone who understands the algorithm used by zlib's deflate for 686 searching for the best matching string, and even then only by the most 687 fanatic optimizer trying to squeeze out the last compressed bit for their 688 specific input data. Read the deflate.c source code for the meaning of the 689 max_lazy, good_length, nice_length, and max_chain parameters. 690 691 deflateTune() can be called after deflateInit() or deflateInit2(), and 692 returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream. 693 */ 694 695 ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm, 696 uLong sourceLen)); 697 /* 698 deflateBound() returns an upper bound on the compressed size after 699 deflation of sourceLen bytes. It must be called after deflateInit() or 700 deflateInit2(), and after deflateSetHeader(), if used. This would be used 701 to allocate an output buffer for deflation in a single pass, and so would be 702 called before deflate(). If that first deflate() call is provided the 703 sourceLen input bytes, an output buffer allocated to the size returned by 704 deflateBound(), and the flush value Z_FINISH, then deflate() is guaranteed 705 to return Z_STREAM_END. Note that it is possible for the compressed size to 706 be larger than the value returned by deflateBound() if flush options other 707 than Z_FINISH or Z_NO_FLUSH are used. 708 */ 709 710 ZEXTERN int ZEXPORT deflatePending OF((z_streamp strm, 711 unsigned *pending, 712 int *bits)); 713 /* 714 deflatePending() returns the number of bytes and bits of output that have 715 been generated, but not yet provided in the available output. The bytes not 716 provided would be due to the available output space having being consumed. 717 The number of bits of output not provided are between 0 and 7, where they 718 await more bits to join them in order to fill out a full byte. If pending 719 or bits are Z_NULL, then those values are not set. 720 721 deflatePending returns Z_OK if success, or Z_STREAM_ERROR if the source 722 stream state was inconsistent. 723 */ 724 725 ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm, 726 int bits, 727 int value)); 728 /* 729 deflatePrime() inserts bits in the deflate output stream. The intent 730 is that this function is used to start off the deflate output with the bits 731 leftover from a previous deflate stream when appending to it. As such, this 732 function can only be used for raw deflate, and must be used before the first 733 deflate() call after a deflateInit2() or deflateReset(). bits must be less 734 than or equal to 16, and that many of the least significant bits of value 735 will be inserted in the output. 736 737 deflatePrime returns Z_OK if success, Z_BUF_ERROR if there was not enough 738 room in the internal buffer to insert the bits, or Z_STREAM_ERROR if the 739 source stream state was inconsistent. 740 */ 741 742 ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm, 743 gz_headerp head)); 744 /* 745 deflateSetHeader() provides gzip header information for when a gzip 746 stream is requested by deflateInit2(). deflateSetHeader() may be called 747 after deflateInit2() or deflateReset() and before the first call of 748 deflate(). The text, time, os, extra field, name, and comment information 749 in the provided gz_header structure are written to the gzip header (xflag is 750 ignored -- the extra flags are set according to the compression level). The 751 caller must assure that, if not Z_NULL, name and comment are terminated with 752 a zero byte, and that if extra is not Z_NULL, that extra_len bytes are 753 available there. If hcrc is true, a gzip header crc is included. Note that 754 the current versions of the command-line version of gzip (up through version 755 1.3.x) do not support header crc's, and will report that it is a "multi-part 756 gzip file" and give up. 757 758 If deflateSetHeader is not used, the default gzip header has text false, 759 the time set to zero, and os set to 255, with no extra, name, or comment 760 fields. The gzip header is returned to the default state by deflateReset(). 761 762 deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source 763 stream state was inconsistent. 764 */ 765 766 /* 767 ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm, 768 int windowBits)); 769 770 This is another version of inflateInit with an extra parameter. The 771 fields next_in, avail_in, zalloc, zfree and opaque must be initialized 772 before by the caller. 773 774 The windowBits parameter is the base two logarithm of the maximum window 775 size (the size of the history buffer). It should be in the range 8..15 for 776 this version of the library. The default value is 15 if inflateInit is used 777 instead. windowBits must be greater than or equal to the windowBits value 778 provided to deflateInit2() while compressing, or it must be equal to 15 if 779 deflateInit2() was not used. If a compressed stream with a larger window 780 size is given as input, inflate() will return with the error code 781 Z_DATA_ERROR instead of trying to allocate a larger window. 782 783 windowBits can also be zero to request that inflate use the window size in 784 the zlib header of the compressed stream. 785 786 windowBits can also be -8..-15 for raw inflate. In this case, -windowBits 787 determines the window size. inflate() will then process raw deflate data, 788 not looking for a zlib or gzip header, not generating a check value, and not 789 looking for any check values for comparison at the end of the stream. This 790 is for use with other formats that use the deflate compressed data format 791 such as zip. Those formats provide their own check values. If a custom 792 format is developed using the raw deflate format for compressed data, it is 793 recommended that a check value such as an adler32 or a crc32 be applied to 794 the uncompressed data as is done in the zlib, gzip, and zip formats. For 795 most applications, the zlib format should be used as is. Note that comments 796 above on the use in deflateInit2() applies to the magnitude of windowBits. 797 798 windowBits can also be greater than 15 for optional gzip decoding. Add 799 32 to windowBits to enable zlib and gzip decoding with automatic header 800 detection, or add 16 to decode only the gzip format (the zlib format will 801 return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is a 802 crc32 instead of an adler32. 803 804 inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 805 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the 806 version assumed by the caller, or Z_STREAM_ERROR if the parameters are 807 invalid, such as a null pointer to the structure. msg is set to null if 808 there is no error message. inflateInit2 does not perform any decompression 809 apart from possibly reading the zlib header if present: actual decompression 810 will be done by inflate(). (So next_in and avail_in may be modified, but 811 next_out and avail_out are unused and unchanged.) The current implementation 812 of inflateInit2() does not process any header information -- that is 813 deferred until inflate() is called. 814 */ 815 816 ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm, 817 const Bytef *dictionary, 818 uInt dictLength)); 819 /* 820 Initializes the decompression dictionary from the given uncompressed byte 821 sequence. This function must be called immediately after a call of inflate, 822 if that call returned Z_NEED_DICT. The dictionary chosen by the compressor 823 can be determined from the adler32 value returned by that call of inflate. 824 The compressor and decompressor must use exactly the same dictionary (see 825 deflateSetDictionary). For raw inflate, this function can be called at any 826 time to set the dictionary. If the provided dictionary is smaller than the 827 window and there is already data in the window, then the provided dictionary 828 will amend what's there. The application must insure that the dictionary 829 that was used for compression is provided. 830 831 inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a 832 parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is 833 inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the 834 expected one (incorrect adler32 value). inflateSetDictionary does not 835 perform any decompression: this will be done by subsequent calls of 836 inflate(). 837 */ 838 839 ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm)); 840 /* 841 Skips invalid compressed data until a possible full flush point (see above 842 for the description of deflate with Z_FULL_FLUSH) can be found, or until all 843 available input is skipped. No output is provided. 844 845 inflateSync searches for a 00 00 FF FF pattern in the compressed data. 846 All full flush points have this pattern, but not all occurences of this 847 pattern are full flush points. 848 849 inflateSync returns Z_OK if a possible full flush point has been found, 850 Z_BUF_ERROR if no more input was provided, Z_DATA_ERROR if no flush point 851 has been found, or Z_STREAM_ERROR if the stream structure was inconsistent. 852 In the success case, the application may save the current current value of 853 total_in which indicates where valid compressed data was found. In the 854 error case, the application may repeatedly call inflateSync, providing more 855 input each time, until success or end of the input data. 856 */ 857 858 ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest, 859 z_streamp source)); 860 /* 861 Sets the destination stream as a complete copy of the source stream. 862 863 This function can be useful when randomly accessing a large stream. The 864 first pass through the stream can periodically record the inflate state, 865 allowing restarting inflate at those points when randomly accessing the 866 stream. 867 868 inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not 869 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent 870 (such as zalloc being Z_NULL). msg is left unchanged in both source and 871 destination. 872 */ 873 874 ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm)); 875 /* 876 This function is equivalent to inflateEnd followed by inflateInit, 877 but does not free and reallocate all the internal decompression state. The 878 stream will keep attributes that may have been set by inflateInit2. 879 880 inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source 881 stream state was inconsistent (such as zalloc or state being Z_NULL). 882 */ 883 884 ZEXTERN int ZEXPORT inflateReset2 OF((z_streamp strm, 885 int windowBits)); 886 /* 887 This function is the same as inflateReset, but it also permits changing 888 the wrap and window size requests. The windowBits parameter is interpreted 889 the same as it is for inflateInit2. 890 891 inflateReset2 returns Z_OK if success, or Z_STREAM_ERROR if the source 892 stream state was inconsistent (such as zalloc or state being Z_NULL), or if 893 the windowBits parameter is invalid. 894 */ 895 896 ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm, 897 int bits, 898 int value)); 899 /* 900 This function inserts bits in the inflate input stream. The intent is 901 that this function is used to start inflating at a bit position in the 902 middle of a byte. The provided bits will be used before any bytes are used 903 from next_in. This function should only be used with raw inflate, and 904 should be used before the first inflate() call after inflateInit2() or 905 inflateReset(). bits must be less than or equal to 16, and that many of the 906 least significant bits of value will be inserted in the input. 907 908 If bits is negative, then the input stream bit buffer is emptied. Then 909 inflatePrime() can be called again to put bits in the buffer. This is used 910 to clear out bits leftover after feeding inflate a block description prior 911 to feeding inflate codes. 912 913 inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source 914 stream state was inconsistent. 915 */ 916 917 ZEXTERN long ZEXPORT inflateMark OF((z_streamp strm)); 918 /* 919 This function returns two values, one in the lower 16 bits of the return 920 value, and the other in the remaining upper bits, obtained by shifting the 921 return value down 16 bits. If the upper value is -1 and the lower value is 922 zero, then inflate() is currently decoding information outside of a block. 923 If the upper value is -1 and the lower value is non-zero, then inflate is in 924 the middle of a stored block, with the lower value equaling the number of 925 bytes from the input remaining to copy. If the upper value is not -1, then 926 it is the number of bits back from the current bit position in the input of 927 the code (literal or length/distance pair) currently being processed. In 928 that case the lower value is the number of bytes already emitted for that 929 code. 930 931 A code is being processed if inflate is waiting for more input to complete 932 decoding of the code, or if it has completed decoding but is waiting for 933 more output space to write the literal or match data. 934 935 inflateMark() is used to mark locations in the input data for random 936 access, which may be at bit positions, and to note those cases where the 937 output of a code may span boundaries of random access blocks. The current 938 location in the input stream can be determined from avail_in and data_type 939 as noted in the description for the Z_BLOCK flush parameter for inflate. 940 941 inflateMark returns the value noted above or -1 << 16 if the provided 942 source stream state was inconsistent. 943 */ 944 945 ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm, 946 gz_headerp head)); 947 /* 948 inflateGetHeader() requests that gzip header information be stored in the 949 provided gz_header structure. inflateGetHeader() may be called after 950 inflateInit2() or inflateReset(), and before the first call of inflate(). 951 As inflate() processes the gzip stream, head->done is zero until the header 952 is completed, at which time head->done is set to one. If a zlib stream is 953 being decoded, then head->done is set to -1 to indicate that there will be 954 no gzip header information forthcoming. Note that Z_BLOCK or Z_TREES can be 955 used to force inflate() to return immediately after header processing is 956 complete and before any actual data is decompressed. 957 958 The text, time, xflags, and os fields are filled in with the gzip header 959 contents. hcrc is set to true if there is a header CRC. (The header CRC 960 was valid if done is set to one.) If extra is not Z_NULL, then extra_max 961 contains the maximum number of bytes to write to extra. Once done is true, 962 extra_len contains the actual extra field length, and extra contains the 963 extra field, or that field truncated if extra_max is less than extra_len. 964 If name is not Z_NULL, then up to name_max characters are written there, 965 terminated with a zero unless the length is greater than name_max. If 966 comment is not Z_NULL, then up to comm_max characters are written there, 967 terminated with a zero unless the length is greater than comm_max. When any 968 of extra, name, or comment are not Z_NULL and the respective field is not 969 present in the header, then that field is set to Z_NULL to signal its 970 absence. This allows the use of deflateSetHeader() with the returned 971 structure to duplicate the header. However if those fields are set to 972 allocated memory, then the application will need to save those pointers 973 elsewhere so that they can be eventually freed. 974 975 If inflateGetHeader is not used, then the header information is simply 976 discarded. The header is always checked for validity, including the header 977 CRC if present. inflateReset() will reset the process to discard the header 978 information. The application would need to call inflateGetHeader() again to 979 retrieve the header from the next gzip stream. 980 981 inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source 982 stream state was inconsistent. 983 */ 984 985 /* 986 ZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits, 987 unsigned char FAR *window)); 988 989 Initialize the internal stream state for decompression using inflateBack() 990 calls. The fields zalloc, zfree and opaque in strm must be initialized 991 before the call. If zalloc and zfree are Z_NULL, then the default library- 992 derived memory allocation routines are used. windowBits is the base two 993 logarithm of the window size, in the range 8..15. window is a caller 994 supplied buffer of that size. Except for special applications where it is 995 assured that deflate was used with small window sizes, windowBits must be 15 996 and a 32K byte window must be supplied to be able to decompress general 997 deflate streams. 998 999 See inflateBack() for the usage of these routines. 1000 1001 inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of 1002 the parameters are invalid, Z_MEM_ERROR if the internal state could not be 1003 allocated, or Z_VERSION_ERROR if the version of the library does not match 1004 the version of the header file. 1005 */ 1006 1007 typedef unsigned (*in_func) OF((void FAR *, unsigned char FAR * FAR *)); 1008 typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned)); 1009 1010 ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm, 1011 in_func in, void FAR *in_desc, 1012 out_func out, void FAR *out_desc)); 1013 /* 1014 inflateBack() does a raw inflate with a single call using a call-back 1015 interface for input and output. This is more efficient than inflate() for 1016 file i/o applications in that it avoids copying between the output and the 1017 sliding window by simply making the window itself the output buffer. This 1018 function trusts the application to not change the output buffer passed by 1019 the output function, at least until inflateBack() returns. 1020 1021 inflateBackInit() must be called first to allocate the internal state 1022 and to initialize the state with the user-provided window buffer. 1023 inflateBack() may then be used multiple times to inflate a complete, raw 1024 deflate stream with each call. inflateBackEnd() is then called to free the 1025 allocated state. 1026 1027 A raw deflate stream is one with no zlib or gzip header or trailer. 1028 This routine would normally be used in a utility that reads zip or gzip 1029 files and writes out uncompressed files. The utility would decode the 1030 header and process the trailer on its own, hence this routine expects only 1031 the raw deflate stream to decompress. This is different from the normal 1032 behavior of inflate(), which expects either a zlib or gzip header and 1033 trailer around the deflate stream. 1034 1035 inflateBack() uses two subroutines supplied by the caller that are then 1036 called by inflateBack() for input and output. inflateBack() calls those 1037 routines until it reads a complete deflate stream and writes out all of the 1038 uncompressed data, or until it encounters an error. The function's 1039 parameters and return types are defined above in the in_func and out_func 1040 typedefs. inflateBack() will call in(in_desc, &buf) which should return the 1041 number of bytes of provided input, and a pointer to that input in buf. If 1042 there is no input available, in() must return zero--buf is ignored in that 1043 case--and inflateBack() will return a buffer error. inflateBack() will call 1044 out(out_desc, buf, len) to write the uncompressed data buf[0..len-1]. out() 1045 should return zero on success, or non-zero on failure. If out() returns 1046 non-zero, inflateBack() will return with an error. Neither in() nor out() 1047 are permitted to change the contents of the window provided to 1048 inflateBackInit(), which is also the buffer that out() uses to write from. 1049 The length written by out() will be at most the window size. Any non-zero 1050 amount of input may be provided by in(). 1051 1052 For convenience, inflateBack() can be provided input on the first call by 1053 setting strm->next_in and strm->avail_in. If that input is exhausted, then 1054 in() will be called. Therefore strm->next_in must be initialized before 1055 calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called 1056 immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in 1057 must also be initialized, and then if strm->avail_in is not zero, input will 1058 initially be taken from strm->next_in[0 .. strm->avail_in - 1]. 1059 1060 The in_desc and out_desc parameters of inflateBack() is passed as the 1061 first parameter of in() and out() respectively when they are called. These 1062 descriptors can be optionally used to pass any information that the caller- 1063 supplied in() and out() functions need to do their job. 1064 1065 On return, inflateBack() will set strm->next_in and strm->avail_in to 1066 pass back any unused input that was provided by the last in() call. The 1067 return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR 1068 if in() or out() returned an error, Z_DATA_ERROR if there was a format error 1069 in the deflate stream (in which case strm->msg is set to indicate the nature 1070 of the error), or Z_STREAM_ERROR if the stream was not properly initialized. 1071 In the case of Z_BUF_ERROR, an input or output error can be distinguished 1072 using strm->next_in which will be Z_NULL only if in() returned an error. If 1073 strm->next_in is not Z_NULL, then the Z_BUF_ERROR was due to out() returning 1074 non-zero. (in() will always be called before out(), so strm->next_in is 1075 assured to be defined if out() returns non-zero.) Note that inflateBack() 1076 cannot return Z_OK. 1077 */ 1078 1079 ZEXTERN int ZEXPORT inflateBackEnd OF((z_streamp strm)); 1080 /* 1081 All memory allocated by inflateBackInit() is freed. 1082 1083 inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream 1084 state was inconsistent. 1085 */ 1086 1087 ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void)); 1088 /* Return flags indicating compile-time options. 1089 1090 Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other: 1091 1.0: size of uInt 1092 3.2: size of uLong 1093 5.4: size of voidpf (pointer) 1094 7.6: size of z_off_t 1095 1096 Compiler, assembler, and debug options: 1097 8: DEBUG 1098 9: ASMV or ASMINF -- use ASM code 1099 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention 1100 11: 0 (reserved) 1101 1102 One-time table building (smaller code, but not thread-safe if true): 1103 12: BUILDFIXED -- build static block decoding tables when needed 1104 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed 1105 14,15: 0 (reserved) 1106 1107 Library content (indicates missing functionality): 1108 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking 1109 deflate code when not needed) 1110 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect 1111 and decode gzip streams (to avoid linking crc code) 1112 18-19: 0 (reserved) 1113 1114 Operation variations (changes in library functionality): 1115 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate 1116 21: FASTEST -- deflate algorithm with only one, lowest compression level 1117 22,23: 0 (reserved) 1118 1119 The sprintf variant used by gzprintf (zero is best): 1120 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format 1121 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure! 1122 26: 0 = returns value, 1 = void -- 1 means inferred string length returned 1123 1124 Remainder: 1125 27-31: 0 (reserved) 1126 */ 1127 1128 #ifndef Z_SOLO 1129 1130 /* utility functions */ 1131 1132 /* 1133 The following utility functions are implemented on top of the basic 1134 stream-oriented functions. To simplify the interface, some default options 1135 are assumed (compression level and memory usage, standard memory allocation 1136 functions). The source code of these utility functions can be modified if 1137 you need special options. 1138 */ 1139 1140 ZEXTERN int ZEXPORT compress OF((Bytef *dest, uLongf *destLen, 1141 const Bytef *source, uLong sourceLen)); 1142 /* 1143 Compresses the source buffer into the destination buffer. sourceLen is 1144 the byte length of the source buffer. Upon entry, destLen is the total size 1145 of the destination buffer, which must be at least the value returned by 1146 compressBound(sourceLen). Upon exit, destLen is the actual size of the 1147 compressed buffer. 1148 1149 compress returns Z_OK if success, Z_MEM_ERROR if there was not 1150 enough memory, Z_BUF_ERROR if there was not enough room in the output 1151 buffer. 1152 */ 1153 1154 ZEXTERN int ZEXPORT compress2 OF((Bytef *dest, uLongf *destLen, 1155 const Bytef *source, uLong sourceLen, 1156 int level)); 1157 /* 1158 Compresses the source buffer into the destination buffer. The level 1159 parameter has the same meaning as in deflateInit. sourceLen is the byte 1160 length of the source buffer. Upon entry, destLen is the total size of the 1161 destination buffer, which must be at least the value returned by 1162 compressBound(sourceLen). Upon exit, destLen is the actual size of the 1163 compressed buffer. 1164 1165 compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 1166 memory, Z_BUF_ERROR if there was not enough room in the output buffer, 1167 Z_STREAM_ERROR if the level parameter is invalid. 1168 */ 1169 1170 ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen)); 1171 /* 1172 compressBound() returns an upper bound on the compressed size after 1173 compress() or compress2() on sourceLen bytes. It would be used before a 1174 compress() or compress2() call to allocate the destination buffer. 1175 */ 1176 1177 ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen, 1178 const Bytef *source, uLong sourceLen)); 1179 /* 1180 Decompresses the source buffer into the destination buffer. sourceLen is 1181 the byte length of the source buffer. Upon entry, destLen is the total size 1182 of the destination buffer, which must be large enough to hold the entire 1183 uncompressed data. (The size of the uncompressed data must have been saved 1184 previously by the compressor and transmitted to the decompressor by some 1185 mechanism outside the scope of this compression library.) Upon exit, destLen 1186 is the actual size of the uncompressed buffer. 1187 1188 uncompress returns Z_OK if success, Z_MEM_ERROR if there was not 1189 enough memory, Z_BUF_ERROR if there was not enough room in the output 1190 buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete. In 1191 the case where there is not enough room, uncompress() will fill the output 1192 buffer with the uncompressed data up to that point. 1193 */ 1194 1195 /* gzip file access functions */ 1196 1197 /* 1198 This library supports reading and writing files in gzip (.gz) format with 1199 an interface similar to that of stdio, using the functions that start with 1200 "gz". The gzip format is different from the zlib format. gzip is a gzip 1201 wrapper, documented in RFC 1952, wrapped around a deflate stream. 1202 */ 1203 1204 typedef struct gzFile_s *gzFile; /* semi-opaque gzip file descriptor */ 1205 1206 /* 1207 ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode)); 1208 1209 Opens a gzip (.gz) file for reading or writing. The mode parameter is as 1210 in fopen ("rb" or "wb") but can also include a compression level ("wb9") or 1211 a strategy: 'f' for filtered data as in "wb6f", 'h' for Huffman-only 1212 compression as in "wb1h", 'R' for run-length encoding as in "wb1R", or 'F' 1213 for fixed code compression as in "wb9F". (See the description of 1214 deflateInit2 for more information about the strategy parameter.) 'T' will 1215 request transparent writing or appending with no compression and not using 1216 the gzip format. 1217 1218 "a" can be used instead of "w" to request that the gzip stream that will 1219 be written be appended to the file. "+" will result in an error, since 1220 reading and writing to the same gzip file is not supported. 1221 1222 These functions, as well as gzip, will read and decode a sequence of gzip 1223 streams in a file. The append function of gzopen() can be used to create 1224 such a file. (Also see gzflush() for another way to do this.) When 1225 appending, gzopen does not test whether the file begins with a gzip stream, 1226 nor does it look for the end of the gzip streams to begin appending. gzopen 1227 will simply append a gzip stream to the existing file. 1228 1229 gzopen can be used to read a file which is not in gzip format; in this 1230 case gzread will directly read from the file without decompression. When 1231 reading, this will be detected automatically by looking for the magic two- 1232 byte gzip header. 1233 1234 gzopen returns NULL if the file could not be opened, if there was 1235 insufficient memory to allocate the gzFile state, or if an invalid mode was 1236 specified (an 'r', 'w', or 'a' was not provided, or '+' was provided). 1237 errno can be checked to determine if the reason gzopen failed was that the 1238 file could not be opened. 1239 */ 1240 1241 ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode)); 1242 /* 1243 gzdopen associates a gzFile with the file descriptor fd. File descriptors 1244 are obtained from calls like open, dup, creat, pipe or fileno (if the file 1245 has been previously opened with fopen). The mode parameter is as in gzopen. 1246 1247 The next call of gzclose on the returned gzFile will also close the file 1248 descriptor fd, just like fclose(fdopen(fd, mode)) closes the file descriptor 1249 fd. If you want to keep fd open, use fd = dup(fd_keep); gz = gzdopen(fd, 1250 mode);. The duplicated descriptor should be saved to avoid a leak, since 1251 gzdopen does not close fd if it fails. If you are using fileno() to get the 1252 file descriptor from a FILE *, then you will have to use dup() to avoid 1253 double-close()ing the file descriptor. Both gzclose() and fclose() will 1254 close the associated file descriptor, so they need to have different file 1255 descriptors. 1256 1257 gzdopen returns NULL if there was insufficient memory to allocate the 1258 gzFile state, if an invalid mode was specified (an 'r', 'w', or 'a' was not 1259 provided, or '+' was provided), or if fd is -1. The file descriptor is not 1260 used until the next gz* read, write, seek, or close operation, so gzdopen 1261 will not detect if fd is invalid (unless fd is -1). 1262 */ 1263 1264 ZEXTERN int ZEXPORT gzbuffer OF((gzFile file, unsigned size)); 1265 /* 1266 Set the internal buffer size used by this library's functions. The 1267 default buffer size is 8192 bytes. This function must be called after 1268 gzopen() or gzdopen(), and before any other calls that read or write the 1269 file. The buffer memory allocation is always deferred to the first read or 1270 write. Two buffers are allocated, either both of the specified size when 1271 writing, or one of the specified size and the other twice that size when 1272 reading. A larger buffer size of, for example, 64K or 128K bytes will 1273 noticeably increase the speed of decompression (reading). 1274 1275 The new buffer size also affects the maximum length for gzprintf(). 1276 1277 gzbuffer() returns 0 on success, or -1 on failure, such as being called 1278 too late. 1279 */ 1280 1281 ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy)); 1282 /* 1283 Dynamically update the compression level or strategy. See the description 1284 of deflateInit2 for the meaning of these parameters. 1285 1286 gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not 1287 opened for writing. 1288 */ 1289 1290 ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len)); 1291 /* 1292 Reads the given number of uncompressed bytes from the compressed file. If 1293 the input file is not in gzip format, gzread copies the given number of 1294 bytes into the buffer directly from the file. 1295 1296 After reaching the end of a gzip stream in the input, gzread will continue 1297 to read, looking for another gzip stream. Any number of gzip streams may be 1298 concatenated in the input file, and will all be decompressed by gzread(). 1299 If something other than a gzip stream is encountered after a gzip stream, 1300 that remaining trailing garbage is ignored (and no error is returned). 1301 1302 gzread can be used to read a gzip file that is being concurrently written. 1303 Upon reaching the end of the input, gzread will return with the available 1304 data. If the error code returned by gzerror is Z_OK or Z_BUF_ERROR, then 1305 gzclearerr can be used to clear the end of file indicator in order to permit 1306 gzread to be tried again. Z_OK indicates that a gzip stream was completed 1307 on the last gzread. Z_BUF_ERROR indicates that the input file ended in the 1308 middle of a gzip stream. Note that gzread does not return -1 in the event 1309 of an incomplete gzip stream. This error is deferred until gzclose(), which 1310 will return Z_BUF_ERROR if the last gzread ended in the middle of a gzip 1311 stream. Alternatively, gzerror can be used before gzclose to detect this 1312 case. 1313 1314 gzread returns the number of uncompressed bytes actually read, less than 1315 len for end of file, or -1 for error. 1316 */ 1317 1318 ZEXTERN int ZEXPORT gzwrite OF((gzFile file, 1319 voidpc buf, unsigned len)); 1320 /* 1321 Writes the given number of uncompressed bytes into the compressed file. 1322 gzwrite returns the number of uncompressed bytes written or 0 in case of 1323 error. 1324 */ 1325 1326 ZEXTERN int ZEXPORTVA gzprintf Z_ARG((gzFile file, const char *format, ...)); 1327 /* 1328 Converts, formats, and writes the arguments to the compressed file under 1329 control of the format string, as in fprintf. gzprintf returns the number of 1330 uncompressed bytes actually written, or 0 in case of error. The number of 1331 uncompressed bytes written is limited to 8191, or one less than the buffer 1332 size given to gzbuffer(). The caller should assure that this limit is not 1333 exceeded. If it is exceeded, then gzprintf() will return an error (0) with 1334 nothing written. In this case, there may also be a buffer overflow with 1335 unpredictable consequences, which is possible only if zlib was compiled with 1336 the insecure functions sprintf() or vsprintf() because the secure snprintf() 1337 or vsnprintf() functions were not available. This can be determined using 1338 zlibCompileFlags(). 1339 */ 1340 1341 ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s)); 1342 /* 1343 Writes the given null-terminated string to the compressed file, excluding 1344 the terminating null character. 1345 1346 gzputs returns the number of characters written, or -1 in case of error. 1347 */ 1348 1349 ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len)); 1350 /* 1351 Reads bytes from the compressed file until len-1 characters are read, or a 1352 newline character is read and transferred to buf, or an end-of-file 1353 condition is encountered. If any characters are read or if len == 1, the 1354 string is terminated with a null character. If no characters are read due 1355 to an end-of-file or len < 1, then the buffer is left untouched. 1356 1357 gzgets returns buf which is a null-terminated string, or it returns NULL 1358 for end-of-file or in case of error. If there was an error, the contents at 1359 buf are indeterminate. 1360 */ 1361 1362 ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c)); 1363 /* 1364 Writes c, converted to an unsigned char, into the compressed file. gzputc 1365 returns the value that was written, or -1 in case of error. 1366 */ 1367 1368 ZEXTERN int ZEXPORT gzgetc OF((gzFile file)); 1369 /* 1370 Reads one byte from the compressed file. gzgetc returns this byte or -1 1371 in case of end of file or error. This is implemented as a macro for speed. 1372 As such, it does not do all of the checking the other functions do. I.e. 1373 it does not check to see if file is NULL, nor whether the structure file 1374 points to has been clobbered or not. 1375 */ 1376 1377 ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file)); 1378 /* 1379 Push one character back onto the stream to be read as the first character 1380 on the next read. At least one character of push-back is allowed. 1381 gzungetc() returns the character pushed, or -1 on failure. gzungetc() will 1382 fail if c is -1, and may fail if a character has been pushed but not read 1383 yet. If gzungetc is used immediately after gzopen or gzdopen, at least the 1384 output buffer size of pushed characters is allowed. (See gzbuffer above.) 1385 The pushed character will be discarded if the stream is repositioned with 1386 gzseek() or gzrewind(). 1387 */ 1388 1389 ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush)); 1390 /* 1391 Flushes all pending output into the compressed file. The parameter flush 1392 is as in the deflate() function. The return value is the zlib error number 1393 (see function gzerror below). gzflush is only permitted when writing. 1394 1395 If the flush parameter is Z_FINISH, the remaining data is written and the 1396 gzip stream is completed in the output. If gzwrite() is called again, a new 1397 gzip stream will be started in the output. gzread() is able to read such 1398 concatented gzip streams. 1399 1400 gzflush should be called only when strictly necessary because it will 1401 degrade compression if called too often. 1402 */ 1403 1404 /* 1405 ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file, 1406 z_off_t offset, int whence)); 1407 1408 Sets the starting position for the next gzread or gzwrite on the given 1409 compressed file. The offset represents a number of bytes in the 1410 uncompressed data stream. The whence parameter is defined as in lseek(2); 1411 the value SEEK_END is not supported. 1412 1413 If the file is opened for reading, this function is emulated but can be 1414 extremely slow. If the file is opened for writing, only forward seeks are 1415 supported; gzseek then compresses a sequence of zeroes up to the new 1416 starting position. 1417 1418 gzseek returns the resulting offset location as measured in bytes from 1419 the beginning of the uncompressed stream, or -1 in case of error, in 1420 particular if the file is opened for writing and the new starting position 1421 would be before the current position. 1422 */ 1423 1424 ZEXTERN int ZEXPORT gzrewind OF((gzFile file)); 1425 /* 1426 Rewinds the given file. This function is supported only for reading. 1427 1428 gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET) 1429 */ 1430 1431 /* 1432 ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file)); 1433 1434 Returns the starting position for the next gzread or gzwrite on the given 1435 compressed file. This position represents a number of bytes in the 1436 uncompressed data stream, and is zero when starting, even if appending or 1437 reading a gzip stream from the middle of a file using gzdopen(). 1438 1439 gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR) 1440 */ 1441 1442 /* 1443 ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile file)); 1444 1445 Returns the current offset in the file being read or written. This offset 1446 includes the count of bytes that precede the gzip stream, for example when 1447 appending or when using gzdopen() for reading. When reading, the offset 1448 does not include as yet unused buffered input. This information can be used 1449 for a progress indicator. On error, gzoffset() returns -1. 1450 */ 1451 1452 ZEXTERN int ZEXPORT gzeof OF((gzFile file)); 1453 /* 1454 Returns true (1) if the end-of-file indicator has been set while reading, 1455 false (0) otherwise. Note that the end-of-file indicator is set only if the 1456 read tried to go past the end of the input, but came up short. Therefore, 1457 just like feof(), gzeof() may return false even if there is no more data to 1458 read, in the event that the last read request was for the exact number of 1459 bytes remaining in the input file. This will happen if the input file size 1460 is an exact multiple of the buffer size. 1461 1462 If gzeof() returns true, then the read functions will return no more data, 1463 unless the end-of-file indicator is reset by gzclearerr() and the input file 1464 has grown since the previous end of file was detected. 1465 */ 1466 1467 ZEXTERN int ZEXPORT gzdirect OF((gzFile file)); 1468 /* 1469 Returns true (1) if file is being copied directly while reading, or false 1470 (0) if file is a gzip stream being decompressed. 1471 1472 If the input file is empty, gzdirect() will return true, since the input 1473 does not contain a gzip stream. 1474 1475 If gzdirect() is used immediately after gzopen() or gzdopen() it will 1476 cause buffers to be allocated to allow reading the file to determine if it 1477 is a gzip file. Therefore if gzbuffer() is used, it should be called before 1478 gzdirect(). 1479 1480 When writing, gzdirect() returns true (1) if transparent writing was 1481 requested ("wT" for the gzopen() mode), or false (0) otherwise. (Note: 1482 gzdirect() is not needed when writing. Transparent writing must be 1483 explicitly requested, so the application already knows the answer. When 1484 linking statically, using gzdirect() will include all of the zlib code for 1485 gzip file reading and decompression, which may not be desired.) 1486 */ 1487 1488 ZEXTERN int ZEXPORT gzclose OF((gzFile file)); 1489 /* 1490 Flushes all pending output if necessary, closes the compressed file and 1491 deallocates the (de)compression state. Note that once file is closed, you 1492 cannot call gzerror with file, since its structures have been deallocated. 1493 gzclose must not be called more than once on the same file, just as free 1494 must not be called more than once on the same allocation. 1495 1496 gzclose will return Z_STREAM_ERROR if file is not valid, Z_ERRNO on a 1497 file operation error, Z_MEM_ERROR if out of memory, Z_BUF_ERROR if the 1498 last read ended in the middle of a gzip stream, or Z_OK on success. 1499 */ 1500 1501 ZEXTERN int ZEXPORT gzclose_r OF((gzFile file)); 1502 ZEXTERN int ZEXPORT gzclose_w OF((gzFile file)); 1503 /* 1504 Same as gzclose(), but gzclose_r() is only for use when reading, and 1505 gzclose_w() is only for use when writing or appending. The advantage to 1506 using these instead of gzclose() is that they avoid linking in zlib 1507 compression or decompression code that is not used when only reading or only 1508 writing respectively. If gzclose() is used, then both compression and 1509 decompression code will be included the application when linking to a static 1510 zlib library. 1511 */ 1512 1513 ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum)); 1514 /* 1515 Returns the error message for the last error which occurred on the given 1516 compressed file. errnum is set to zlib error number. If an error occurred 1517 in the file system and not in the compression library, errnum is set to 1518 Z_ERRNO and the application may consult errno to get the exact error code. 1519 1520 The application must not modify the returned string. Future calls to 1521 this function may invalidate the previously returned string. If file is 1522 closed, then the string previously returned by gzerror will no longer be 1523 available. 1524 1525 gzerror() should be used to distinguish errors from end-of-file for those 1526 functions above that do not distinguish those cases in their return values. 1527 */ 1528 1529 ZEXTERN void ZEXPORT gzclearerr OF((gzFile file)); 1530 /* 1531 Clears the error and end-of-file flags for file. This is analogous to the 1532 clearerr() function in stdio. This is useful for continuing to read a gzip 1533 file that is being written concurrently. 1534 */ 1535 1536 #endif /* !Z_SOLO */ 1537 1538 /* checksum functions */ 1539 1540 /* 1541 These functions are not related to compression but are exported 1542 anyway because they might be useful in applications using the compression 1543 library. 1544 */ 1545 1546 ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len)); 1547 /* 1548 Update a running Adler-32 checksum with the bytes buf[0..len-1] and 1549 return the updated checksum. If buf is Z_NULL, this function returns the 1550 required initial value for the checksum. 1551 1552 An Adler-32 checksum is almost as reliable as a CRC32 but can be computed 1553 much faster. 1554 1555 Usage example: 1556 1557 uLong adler = adler32(0L, Z_NULL, 0); 1558 1559 while (read_buffer(buffer, length) != EOF) { 1560 adler = adler32(adler, buffer, length); 1561 } 1562 if (adler != original_adler) error(); 1563 */ 1564 1565 /* 1566 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong adler1, uLong adler2, 1567 z_off_t len2)); 1568 1569 Combine two Adler-32 checksums into one. For two sequences of bytes, seq1 1570 and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for 1571 each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of 1572 seq1 and seq2 concatenated, requiring only adler1, adler2, and len2. Note 1573 that the z_off_t type (like off_t) is a signed integer. If len2 is 1574 negative, the result has no meaning or utility. 1575 */ 1576 1577 ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len)); 1578 /* 1579 Update a running CRC-32 with the bytes buf[0..len-1] and return the 1580 updated CRC-32. If buf is Z_NULL, this function returns the required 1581 initial value for the for the crc. Pre- and post-conditioning (one's 1582 complement) is performed within this function so it shouldn't be done by the 1583 application. 1584 1585 Usage example: 1586 1587 uLong crc = crc32(0L, Z_NULL, 0); 1588 1589 while (read_buffer(buffer, length) != EOF) { 1590 crc = crc32(crc, buffer, length); 1591 } 1592 if (crc != original_crc) error(); 1593 */ 1594 1595 /* 1596 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2)); 1597 1598 Combine two CRC-32 check values into one. For two sequences of bytes, 1599 seq1 and seq2 with lengths len1 and len2, CRC-32 check values were 1600 calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32 1601 check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and 1602 len2. 1603 */ 1604 1605 1606 /* various hacks, don't look :) */ 1607 1608 /* deflateInit and inflateInit are macros to allow checking the zlib version 1609 * and the compiler's view of z_stream: 1610 */ 1611 ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level, 1612 const char *version, int stream_size)); 1613 ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm, 1614 const char *version, int stream_size)); 1615 ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method, 1616 int windowBits, int memLevel, 1617 int strategy, const char *version, 1618 int stream_size)); 1619 ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits, 1620 const char *version, int stream_size)); 1621 ZEXTERN int ZEXPORT inflateBackInit_ OF((z_streamp strm, int windowBits, 1622 unsigned char FAR *window, 1623 const char *version, 1624 int stream_size)); 1625 #define deflateInit(strm, level) \ 1626 deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream)) 1627 #define inflateInit(strm) \ 1628 inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream)) 1629 #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \ 1630 deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\ 1631 (strategy), ZLIB_VERSION, (int)sizeof(z_stream)) 1632 #define inflateInit2(strm, windowBits) \ 1633 inflateInit2_((strm), (windowBits), ZLIB_VERSION, \ 1634 (int)sizeof(z_stream)) 1635 #define inflateBackInit(strm, windowBits, window) \ 1636 inflateBackInit_((strm), (windowBits), (window), \ 1637 ZLIB_VERSION, (int)sizeof(z_stream)) 1638 1639 #ifndef Z_SOLO 1640 1641 /* gzgetc() macro and its supporting function and exposed data structure. Note 1642 * that the real internal state is much larger than the exposed structure. 1643 * This abbreviated structure exposes just enough for the gzgetc() macro. The 1644 * user should not mess with these exposed elements, since their names or 1645 * behavior could change in the future, perhaps even capriciously. They can 1646 * only be used by the gzgetc() macro. You have been warned. 1647 */ 1648 struct gzFile_s { 1649 unsigned have; 1650 unsigned char *next; 1651 z_off64_t pos; 1652 }; 1653 ZEXTERN int ZEXPORT gzgetc_ OF((gzFile file)); 1654 #define gzgetc(g) \ 1655 ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : gzgetc_(g)) 1656 1657 /* provide 64-bit offset functions if _LARGEFILE64_SOURCE defined, and/or 1658 * change the regular functions to 64 bits if _FILE_OFFSET_BITS is 64 (if 1659 * both are true, the application gets the *64 functions, and the regular 1660 * functions are changed to 64 bits) -- in case these are set on systems 1661 * without large file support, _LFS64_LARGEFILE must also be true 1662 */ 1663 #if defined(_LARGEFILE64_SOURCE) && _LFS64_LARGEFILE-0 1664 ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *)); 1665 ZEXTERN z_off64_t ZEXPORT gzseek64 OF((gzFile, z_off64_t, int)); 1666 ZEXTERN z_off64_t ZEXPORT gztell64 OF((gzFile)); 1667 ZEXTERN z_off64_t ZEXPORT gzoffset64 OF((gzFile)); 1668 ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off64_t)); 1669 ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off64_t)); 1670 #endif 1671 1672 #if !defined(ZLIB_INTERNAL) && _FILE_OFFSET_BITS-0 == 64 && _LFS64_LARGEFILE-0 1673 # ifdef Z_PREFIX_SET 1674 # define z_gzopen z_gzopen64 1675 # define z_gzseek z_gzseek64 1676 # define z_gztell z_gztell64 1677 # define z_gzoffset z_gzoffset64 1678 # define z_adler32_combine z_adler32_combine64 1679 # define z_crc32_combine z_crc32_combine64 1680 # else 1681 # define gzopen gzopen64 1682 # define gzseek gzseek64 1683 # define gztell gztell64 1684 # define gzoffset gzoffset64 1685 # define adler32_combine adler32_combine64 1686 # define crc32_combine crc32_combine64 1687 # endif 1688 # ifndef _LARGEFILE64_SOURCE 1689 ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *)); 1690 ZEXTERN z_off_t ZEXPORT gzseek64 OF((gzFile, z_off_t, int)); 1691 ZEXTERN z_off_t ZEXPORT gztell64 OF((gzFile)); 1692 ZEXTERN z_off_t ZEXPORT gzoffset64 OF((gzFile)); 1693 ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off_t)); 1694 ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off_t)); 1695 # endif 1696 #else 1697 ZEXTERN gzFile ZEXPORT gzopen OF((const char *, const char *)); 1698 ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile, z_off_t, int)); 1699 ZEXTERN z_off_t ZEXPORT gztell OF((gzFile)); 1700 ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile)); 1701 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t)); 1702 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t)); 1703 #endif 1704 1705 #else /* Z_SOLO */ 1706 1707 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t)); 1708 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t)); 1709 1710 #endif /* !Z_SOLO */ 1711 1712 /* hack for buggy compilers */ 1713 #if !defined(ZUTIL_H) && !defined(NO_DUMMY_DECL) 1714 struct internal_state {int dummy;}; 1715 #endif 1716 1717 /* undocumented functions */ 1718 ZEXTERN const char * ZEXPORT zError OF((int)); 1719 ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp)); 1720 ZEXTERN const uLongf * ZEXPORT get_crc_table OF((void)); 1721 ZEXTERN int ZEXPORT inflateUndermine OF((z_streamp, int)); 1722 ZEXTERN int ZEXPORT inflateResetKeep OF((z_streamp)); 1723 ZEXTERN int ZEXPORT deflateResetKeep OF((z_streamp)); 1724 #ifndef Z_SOLO 1725 ZEXTERN unsigned long ZEXPORT gzflags OF((void)); 1726 #endif 1727 1728 #ifdef __cplusplus 1729 } 1730 #endif 1731 1732 #endif /* ZLIB_H */ 1733
