1 /* zlib.h -- interface of the 'zlib' general purpose compression library 2 version 1.2.8, April 28th, 2013 3 4 Copyright (C) 1995-2013 Jean-loup Gailly and Mark Adler 5 6 This software is provided 'as-is', without any express or implied 7 warranty. In no event will the authors be held liable for any damages 8 arising from the use of this software. 9 10 Permission is granted to anyone to use this software for any purpose, 11 including commercial applications, and to alter it and redistribute it 12 freely, subject to the following restrictions: 13 14 1. The origin of this software must not be misrepresented; you must not 15 claim that you wrote the original software. If you use this software 16 in a product, an acknowledgment in the product documentation would be 17 appreciated but is not required. 18 2. Altered source versions must be plainly marked as such, and must not be 19 misrepresented as being the original software. 20 3. This notice may not be removed or altered from any source distribution. 21 22 Jean-loup Gailly Mark Adler 23 jloup@gzip.org madler@alumni.caltech.edu 24 25 26 The data format used by the zlib library is described by RFCs (Request for 27 Comments) 1950 to 1952 in the files http://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 "1.2.8" 41 #define ZLIB_VERNUM 0x1280 42 #define ZLIB_VER_MAJOR 1 43 #define ZLIB_VER_MINOR 2 44 #define ZLIB_VER_REVISION 8 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 of the uncompressed data for the 456 operation to complete. (The size of the uncompressed data may have been 457 saved by the compressor for this purpose.) The use of Z_FINISH is not 458 required to perform an inflation in one step. However it may be used to 459 inform inflate that a faster approach can be used for the single inflate() 460 call. Z_FINISH also informs inflate to not maintain a sliding window if the 461 stream completes, which reduces inflate's memory footprint. If the stream 462 does not complete, either because not all of the stream is provided or not 463 enough output space is provided, then a sliding window will be allocated and 464 inflate() can be called again to continue the operation as if Z_NO_FLUSH had 465 been used. 466 467 In this implementation, inflate() always flushes as much output as 468 possible to the output buffer, and always uses the faster approach on the 469 first call. So the effects of the flush parameter in this implementation are 470 on the return value of inflate() as noted below, when inflate() returns early 471 when Z_BLOCK or Z_TREES is used, and when inflate() avoids the allocation of 472 memory for a sliding window when Z_FINISH is used. 473 474 If a preset dictionary is needed after this call (see inflateSetDictionary 475 below), inflate sets strm->adler to the Adler-32 checksum of the dictionary 476 chosen by the compressor and returns Z_NEED_DICT; otherwise it sets 477 strm->adler to the Adler-32 checksum of all output produced so far (that is, 478 total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described 479 below. At the end of the stream, inflate() checks that its computed adler32 480 checksum is equal to that saved by the compressor and returns Z_STREAM_END 481 only if the checksum is correct. 482 483 inflate() can decompress and check either zlib-wrapped or gzip-wrapped 484 deflate data. The header type is detected automatically, if requested when 485 initializing with inflateInit2(). Any information contained in the gzip 486 header is not retained, so applications that need that information should 487 instead use raw inflate, see inflateInit2() below, or inflateBack() and 488 perform their own processing of the gzip header and trailer. When processing 489 gzip-wrapped deflate data, strm->adler32 is set to the CRC-32 of the output 490 producted so far. The CRC-32 is checked against the gzip trailer. 491 492 inflate() returns Z_OK if some progress has been made (more input processed 493 or more output produced), Z_STREAM_END if the end of the compressed data has 494 been reached and all uncompressed output has been produced, Z_NEED_DICT if a 495 preset dictionary is needed at this point, Z_DATA_ERROR if the input data was 496 corrupted (input stream not conforming to the zlib format or incorrect check 497 value), Z_STREAM_ERROR if the stream structure was inconsistent (for example 498 next_in or next_out was Z_NULL), Z_MEM_ERROR if there was not enough memory, 499 Z_BUF_ERROR if no progress is possible or if there was not enough room in the 500 output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and 501 inflate() can be called again with more input and more output space to 502 continue decompressing. If Z_DATA_ERROR is returned, the application may 503 then call inflateSync() to look for a good compression block if a partial 504 recovery of the data is desired. 505 */ 506 507 508 ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm)); 509 /* 510 All dynamically allocated data structures for this stream are freed. 511 This function discards any unprocessed input and does not flush any pending 512 output. 513 514 inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state 515 was inconsistent. In the error case, msg may be set but then points to a 516 static string (which must not be deallocated). 517 */ 518 519 520 /* Advanced functions */ 521 522 /* 523 The following functions are needed only in some special applications. 524 */ 525 526 /* 527 ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm, 528 int level, 529 int method, 530 int windowBits, 531 int memLevel, 532 int strategy)); 533 534 This is another version of deflateInit with more compression options. The 535 fields next_in, zalloc, zfree and opaque must be initialized before by the 536 caller. 537 538 The method parameter is the compression method. It must be Z_DEFLATED in 539 this version of the library. 540 541 The windowBits parameter is the base two logarithm of the window size 542 (the size of the history buffer). It should be in the range 8..15 for this 543 version of the library. Larger values of this parameter result in better 544 compression at the expense of memory usage. The default value is 15 if 545 deflateInit is used instead. 546 547 windowBits can also be -8..-15 for raw deflate. In this case, -windowBits 548 determines the window size. deflate() will then generate raw deflate data 549 with no zlib header or trailer, and will not compute an adler32 check value. 550 551 windowBits can also be greater than 15 for optional gzip encoding. Add 552 16 to windowBits to write a simple gzip header and trailer around the 553 compressed data instead of a zlib wrapper. The gzip header will have no 554 file name, no extra data, no comment, no modification time (set to zero), no 555 header crc, and the operating system will be set to 255 (unknown). If a 556 gzip stream is being written, strm->adler is a crc32 instead of an adler32. 557 558 The memLevel parameter specifies how much memory should be allocated 559 for the internal compression state. memLevel=1 uses minimum memory but is 560 slow and reduces compression ratio; memLevel=9 uses maximum memory for 561 optimal speed. The default value is 8. See zconf.h for total memory usage 562 as a function of windowBits and memLevel. 563 564 The strategy parameter is used to tune the compression algorithm. Use the 565 value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a 566 filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no 567 string match), or Z_RLE to limit match distances to one (run-length 568 encoding). Filtered data consists mostly of small values with a somewhat 569 random distribution. In this case, the compression algorithm is tuned to 570 compress them better. The effect of Z_FILTERED is to force more Huffman 571 coding and less string matching; it is somewhat intermediate between 572 Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as 573 fast as Z_HUFFMAN_ONLY, but give better compression for PNG image data. The 574 strategy parameter only affects the compression ratio but not the 575 correctness of the compressed output even if it is not set appropriately. 576 Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler 577 decoder for special applications. 578 579 deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 580 memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid 581 method), or Z_VERSION_ERROR if the zlib library version (zlib_version) is 582 incompatible with the version assumed by the caller (ZLIB_VERSION). msg is 583 set to null if there is no error message. deflateInit2 does not perform any 584 compression: this will be done by deflate(). 585 */ 586 587 ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm, 588 const Bytef *dictionary, 589 uInt dictLength)); 590 /* 591 Initializes the compression dictionary from the given byte sequence 592 without producing any compressed output. When using the zlib format, this 593 function must be called immediately after deflateInit, deflateInit2 or 594 deflateReset, and before any call of deflate. When doing raw deflate, this 595 function must be called either before any call of deflate, or immediately 596 after the completion of a deflate block, i.e. after all input has been 597 consumed and all output has been delivered when using any of the flush 598 options Z_BLOCK, Z_PARTIAL_FLUSH, Z_SYNC_FLUSH, or Z_FULL_FLUSH. The 599 compressor and decompressor must use exactly the same dictionary (see 600 inflateSetDictionary). 601 602 The dictionary should consist of strings (byte sequences) that are likely 603 to be encountered later in the data to be compressed, with the most commonly 604 used strings preferably put towards the end of the dictionary. Using a 605 dictionary is most useful when the data to be compressed is short and can be 606 predicted with good accuracy; the data can then be compressed better than 607 with the default empty dictionary. 608 609 Depending on the size of the compression data structures selected by 610 deflateInit or deflateInit2, a part of the dictionary may in effect be 611 discarded, for example if the dictionary is larger than the window size 612 provided in deflateInit or deflateInit2. Thus the strings most likely to be 613 useful should be put at the end of the dictionary, not at the front. In 614 addition, the current implementation of deflate will use at most the window 615 size minus 262 bytes of the provided dictionary. 616 617 Upon return of this function, strm->adler is set to the adler32 value 618 of the dictionary; the decompressor may later use this value to determine 619 which dictionary has been used by the compressor. (The adler32 value 620 applies to the whole dictionary even if only a subset of the dictionary is 621 actually used by the compressor.) If a raw deflate was requested, then the 622 adler32 value is not computed and strm->adler is not set. 623 624 deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a 625 parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is 626 inconsistent (for example if deflate has already been called for this stream 627 or if not at a block boundary for raw deflate). deflateSetDictionary does 628 not perform any compression: this will be done by deflate(). 629 */ 630 631 ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest, 632 z_streamp source)); 633 /* 634 Sets the destination stream as a complete copy of the source stream. 635 636 This function can be useful when several compression strategies will be 637 tried, for example when there are several ways of pre-processing the input 638 data with a filter. The streams that will be discarded should then be freed 639 by calling deflateEnd. Note that deflateCopy duplicates the internal 640 compression state which can be quite large, so this strategy is slow and can 641 consume lots of memory. 642 643 deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not 644 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent 645 (such as zalloc being Z_NULL). msg is left unchanged in both source and 646 destination. 647 */ 648 649 ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm)); 650 /* 651 This function is equivalent to deflateEnd followed by deflateInit, 652 but does not free and reallocate all the internal compression state. The 653 stream will keep the same compression level and any other attributes that 654 may have been set by deflateInit2. 655 656 deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source 657 stream state was inconsistent (such as zalloc or state being Z_NULL). 658 */ 659 660 ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm, 661 int level, 662 int strategy)); 663 /* 664 Dynamically update the compression level and compression strategy. The 665 interpretation of level and strategy is as in deflateInit2. This can be 666 used to switch between compression and straight copy of the input data, or 667 to switch to a different kind of input data requiring a different strategy. 668 If the compression level is changed, the input available so far is 669 compressed with the old level (and may be flushed); the new level will take 670 effect only at the next call of deflate(). 671 672 Before the call of deflateParams, the stream state must be set as for 673 a call of deflate(), since the currently available input may have to be 674 compressed and flushed. In particular, strm->avail_out must be non-zero. 675 676 deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source 677 stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR if 678 strm->avail_out was zero. 679 */ 680 681 ZEXTERN int ZEXPORT deflateTune OF((z_streamp strm, 682 int good_length, 683 int max_lazy, 684 int nice_length, 685 int max_chain)); 686 /* 687 Fine tune deflate's internal compression parameters. This should only be 688 used by someone who understands the algorithm used by zlib's deflate for 689 searching for the best matching string, and even then only by the most 690 fanatic optimizer trying to squeeze out the last compressed bit for their 691 specific input data. Read the deflate.c source code for the meaning of the 692 max_lazy, good_length, nice_length, and max_chain parameters. 693 694 deflateTune() can be called after deflateInit() or deflateInit2(), and 695 returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream. 696 */ 697 698 ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm, 699 uLong sourceLen)); 700 /* 701 deflateBound() returns an upper bound on the compressed size after 702 deflation of sourceLen bytes. It must be called after deflateInit() or 703 deflateInit2(), and after deflateSetHeader(), if used. This would be used 704 to allocate an output buffer for deflation in a single pass, and so would be 705 called before deflate(). If that first deflate() call is provided the 706 sourceLen input bytes, an output buffer allocated to the size returned by 707 deflateBound(), and the flush value Z_FINISH, then deflate() is guaranteed 708 to return Z_STREAM_END. Note that it is possible for the compressed size to 709 be larger than the value returned by deflateBound() if flush options other 710 than Z_FINISH or Z_NO_FLUSH are used. 711 */ 712 713 ZEXTERN int ZEXPORT deflatePending OF((z_streamp strm, 714 unsigned *pending, 715 int *bits)); 716 /* 717 deflatePending() returns the number of bytes and bits of output that have 718 been generated, but not yet provided in the available output. The bytes not 719 provided would be due to the available output space having being consumed. 720 The number of bits of output not provided are between 0 and 7, where they 721 await more bits to join them in order to fill out a full byte. If pending 722 or bits are Z_NULL, then those values are not set. 723 724 deflatePending returns Z_OK if success, or Z_STREAM_ERROR if the source 725 stream state was inconsistent. 726 */ 727 728 ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm, 729 int bits, 730 int value)); 731 /* 732 deflatePrime() inserts bits in the deflate output stream. The intent 733 is that this function is used to start off the deflate output with the bits 734 leftover from a previous deflate stream when appending to it. As such, this 735 function can only be used for raw deflate, and must be used before the first 736 deflate() call after a deflateInit2() or deflateReset(). bits must be less 737 than or equal to 16, and that many of the least significant bits of value 738 will be inserted in the output. 739 740 deflatePrime returns Z_OK if success, Z_BUF_ERROR if there was not enough 741 room in the internal buffer to insert the bits, or Z_STREAM_ERROR if the 742 source stream state was inconsistent. 743 */ 744 745 ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm, 746 gz_headerp head)); 747 /* 748 deflateSetHeader() provides gzip header information for when a gzip 749 stream is requested by deflateInit2(). deflateSetHeader() may be called 750 after deflateInit2() or deflateReset() and before the first call of 751 deflate(). The text, time, os, extra field, name, and comment information 752 in the provided gz_header structure are written to the gzip header (xflag is 753 ignored -- the extra flags are set according to the compression level). The 754 caller must assure that, if not Z_NULL, name and comment are terminated with 755 a zero byte, and that if extra is not Z_NULL, that extra_len bytes are 756 available there. If hcrc is true, a gzip header crc is included. Note that 757 the current versions of the command-line version of gzip (up through version 758 1.3.x) do not support header crc's, and will report that it is a "multi-part 759 gzip file" and give up. 760 761 If deflateSetHeader is not used, the default gzip header has text false, 762 the time set to zero, and os set to 255, with no extra, name, or comment 763 fields. The gzip header is returned to the default state by deflateReset(). 764 765 deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source 766 stream state was inconsistent. 767 */ 768 769 /* 770 ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm, 771 int windowBits)); 772 773 This is another version of inflateInit with an extra parameter. The 774 fields next_in, avail_in, zalloc, zfree and opaque must be initialized 775 before by the caller. 776 777 The windowBits parameter is the base two logarithm of the maximum window 778 size (the size of the history buffer). It should be in the range 8..15 for 779 this version of the library. The default value is 15 if inflateInit is used 780 instead. windowBits must be greater than or equal to the windowBits value 781 provided to deflateInit2() while compressing, or it must be equal to 15 if 782 deflateInit2() was not used. If a compressed stream with a larger window 783 size is given as input, inflate() will return with the error code 784 Z_DATA_ERROR instead of trying to allocate a larger window. 785 786 windowBits can also be zero to request that inflate use the window size in 787 the zlib header of the compressed stream. 788 789 windowBits can also be -8..-15 for raw inflate. In this case, -windowBits 790 determines the window size. inflate() will then process raw deflate data, 791 not looking for a zlib or gzip header, not generating a check value, and not 792 looking for any check values for comparison at the end of the stream. This 793 is for use with other formats that use the deflate compressed data format 794 such as zip. Those formats provide their own check values. If a custom 795 format is developed using the raw deflate format for compressed data, it is 796 recommended that a check value such as an adler32 or a crc32 be applied to 797 the uncompressed data as is done in the zlib, gzip, and zip formats. For 798 most applications, the zlib format should be used as is. Note that comments 799 above on the use in deflateInit2() applies to the magnitude of windowBits. 800 801 windowBits can also be greater than 15 for optional gzip decoding. Add 802 32 to windowBits to enable zlib and gzip decoding with automatic header 803 detection, or add 16 to decode only the gzip format (the zlib format will 804 return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is a 805 crc32 instead of an adler32. 806 807 inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 808 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the 809 version assumed by the caller, or Z_STREAM_ERROR if the parameters are 810 invalid, such as a null pointer to the structure. msg is set to null if 811 there is no error message. inflateInit2 does not perform any decompression 812 apart from possibly reading the zlib header if present: actual decompression 813 will be done by inflate(). (So next_in and avail_in may be modified, but 814 next_out and avail_out are unused and unchanged.) The current implementation 815 of inflateInit2() does not process any header information -- that is 816 deferred until inflate() is called. 817 */ 818 819 ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm, 820 const Bytef *dictionary, 821 uInt dictLength)); 822 /* 823 Initializes the decompression dictionary from the given uncompressed byte 824 sequence. This function must be called immediately after a call of inflate, 825 if that call returned Z_NEED_DICT. The dictionary chosen by the compressor 826 can be determined from the adler32 value returned by that call of inflate. 827 The compressor and decompressor must use exactly the same dictionary (see 828 deflateSetDictionary). For raw inflate, this function can be called at any 829 time to set the dictionary. If the provided dictionary is smaller than the 830 window and there is already data in the window, then the provided dictionary 831 will amend what's there. The application must insure that the dictionary 832 that was used for compression is provided. 833 834 inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a 835 parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is 836 inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the 837 expected one (incorrect adler32 value). inflateSetDictionary does not 838 perform any decompression: this will be done by subsequent calls of 839 inflate(). 840 */ 841 842 ZEXTERN int ZEXPORT inflateGetDictionary OF((z_streamp strm, 843 Bytef *dictionary, 844 uInt *dictLength)); 845 /* 846 Returns the sliding dictionary being maintained by inflate. dictLength is 847 set to the number of bytes in the dictionary, and that many bytes are copied 848 to dictionary. dictionary must have enough space, where 32768 bytes is 849 always enough. If inflateGetDictionary() is called with dictionary equal to 850 Z_NULL, then only the dictionary length is returned, and nothing is copied. 851 Similary, if dictLength is Z_NULL, then it is not set. 852 853 inflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the 854 stream state is inconsistent. 855 */ 856 857 ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm)); 858 /* 859 Skips invalid compressed data until a possible full flush point (see above 860 for the description of deflate with Z_FULL_FLUSH) can be found, or until all 861 available input is skipped. No output is provided. 862 863 inflateSync searches for a 00 00 FF FF pattern in the compressed data. 864 All full flush points have this pattern, but not all occurrences of this 865 pattern are full flush points. 866 867 inflateSync returns Z_OK if a possible full flush point has been found, 868 Z_BUF_ERROR if no more input was provided, Z_DATA_ERROR if no flush point 869 has been found, or Z_STREAM_ERROR if the stream structure was inconsistent. 870 In the success case, the application may save the current current value of 871 total_in which indicates where valid compressed data was found. In the 872 error case, the application may repeatedly call inflateSync, providing more 873 input each time, until success or end of the input data. 874 */ 875 876 ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest, 877 z_streamp source)); 878 /* 879 Sets the destination stream as a complete copy of the source stream. 880 881 This function can be useful when randomly accessing a large stream. The 882 first pass through the stream can periodically record the inflate state, 883 allowing restarting inflate at those points when randomly accessing the 884 stream. 885 886 inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not 887 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent 888 (such as zalloc being Z_NULL). msg is left unchanged in both source and 889 destination. 890 */ 891 892 ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm)); 893 /* 894 This function is equivalent to inflateEnd followed by inflateInit, 895 but does not free and reallocate all the internal decompression state. The 896 stream will keep attributes that may have been set by inflateInit2. 897 898 inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source 899 stream state was inconsistent (such as zalloc or state being Z_NULL). 900 */ 901 902 ZEXTERN int ZEXPORT inflateReset2 OF((z_streamp strm, 903 int windowBits)); 904 /* 905 This function is the same as inflateReset, but it also permits changing 906 the wrap and window size requests. The windowBits parameter is interpreted 907 the same as it is for inflateInit2. 908 909 inflateReset2 returns Z_OK if success, or Z_STREAM_ERROR if the source 910 stream state was inconsistent (such as zalloc or state being Z_NULL), or if 911 the windowBits parameter is invalid. 912 */ 913 914 ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm, 915 int bits, 916 int value)); 917 /* 918 This function inserts bits in the inflate input stream. The intent is 919 that this function is used to start inflating at a bit position in the 920 middle of a byte. The provided bits will be used before any bytes are used 921 from next_in. This function should only be used with raw inflate, and 922 should be used before the first inflate() call after inflateInit2() or 923 inflateReset(). bits must be less than or equal to 16, and that many of the 924 least significant bits of value will be inserted in the input. 925 926 If bits is negative, then the input stream bit buffer is emptied. Then 927 inflatePrime() can be called again to put bits in the buffer. This is used 928 to clear out bits leftover after feeding inflate a block description prior 929 to feeding inflate codes. 930 931 inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source 932 stream state was inconsistent. 933 */ 934 935 ZEXTERN long ZEXPORT inflateMark OF((z_streamp strm)); 936 /* 937 This function returns two values, one in the lower 16 bits of the return 938 value, and the other in the remaining upper bits, obtained by shifting the 939 return value down 16 bits. If the upper value is -1 and the lower value is 940 zero, then inflate() is currently decoding information outside of a block. 941 If the upper value is -1 and the lower value is non-zero, then inflate is in 942 the middle of a stored block, with the lower value equaling the number of 943 bytes from the input remaining to copy. If the upper value is not -1, then 944 it is the number of bits back from the current bit position in the input of 945 the code (literal or length/distance pair) currently being processed. In 946 that case the lower value is the number of bytes already emitted for that 947 code. 948 949 A code is being processed if inflate is waiting for more input to complete 950 decoding of the code, or if it has completed decoding but is waiting for 951 more output space to write the literal or match data. 952 953 inflateMark() is used to mark locations in the input data for random 954 access, which may be at bit positions, and to note those cases where the 955 output of a code may span boundaries of random access blocks. The current 956 location in the input stream can be determined from avail_in and data_type 957 as noted in the description for the Z_BLOCK flush parameter for inflate. 958 959 inflateMark returns the value noted above or -1 << 16 if the provided 960 source stream state was inconsistent. 961 */ 962 963 ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm, 964 gz_headerp head)); 965 /* 966 inflateGetHeader() requests that gzip header information be stored in the 967 provided gz_header structure. inflateGetHeader() may be called after 968 inflateInit2() or inflateReset(), and before the first call of inflate(). 969 As inflate() processes the gzip stream, head->done is zero until the header 970 is completed, at which time head->done is set to one. If a zlib stream is 971 being decoded, then head->done is set to -1 to indicate that there will be 972 no gzip header information forthcoming. Note that Z_BLOCK or Z_TREES can be 973 used to force inflate() to return immediately after header processing is 974 complete and before any actual data is decompressed. 975 976 The text, time, xflags, and os fields are filled in with the gzip header 977 contents. hcrc is set to true if there is a header CRC. (The header CRC 978 was valid if done is set to one.) If extra is not Z_NULL, then extra_max 979 contains the maximum number of bytes to write to extra. Once done is true, 980 extra_len contains the actual extra field length, and extra contains the 981 extra field, or that field truncated if extra_max is less than extra_len. 982 If name is not Z_NULL, then up to name_max characters are written there, 983 terminated with a zero unless the length is greater than name_max. If 984 comment is not Z_NULL, then up to comm_max characters are written there, 985 terminated with a zero unless the length is greater than comm_max. When any 986 of extra, name, or comment are not Z_NULL and the respective field is not 987 present in the header, then that field is set to Z_NULL to signal its 988 absence. This allows the use of deflateSetHeader() with the returned 989 structure to duplicate the header. However if those fields are set to 990 allocated memory, then the application will need to save those pointers 991 elsewhere so that they can be eventually freed. 992 993 If inflateGetHeader is not used, then the header information is simply 994 discarded. The header is always checked for validity, including the header 995 CRC if present. inflateReset() will reset the process to discard the header 996 information. The application would need to call inflateGetHeader() again to 997 retrieve the header from the next gzip stream. 998 999 inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source 1000 stream state was inconsistent. 1001 */ 1002 1003 /* 1004 ZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits, 1005 unsigned char FAR *window)); 1006 1007 Initialize the internal stream state for decompression using inflateBack() 1008 calls. The fields zalloc, zfree and opaque in strm must be initialized 1009 before the call. If zalloc and zfree are Z_NULL, then the default library- 1010 derived memory allocation routines are used. windowBits is the base two 1011 logarithm of the window size, in the range 8..15. window is a caller 1012 supplied buffer of that size. Except for special applications where it is 1013 assured that deflate was used with small window sizes, windowBits must be 15 1014 and a 32K byte window must be supplied to be able to decompress general 1015 deflate streams. 1016 1017 See inflateBack() for the usage of these routines. 1018 1019 inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of 1020 the parameters are invalid, Z_MEM_ERROR if the internal state could not be 1021 allocated, or Z_VERSION_ERROR if the version of the library does not match 1022 the version of the header file. 1023 */ 1024 1025 typedef unsigned (*in_func) OF((void FAR *, 1026 z_const unsigned char FAR * FAR *)); 1027 typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned)); 1028 1029 ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm, 1030 in_func in, void FAR *in_desc, 1031 out_func out, void FAR *out_desc)); 1032 /* 1033 inflateBack() does a raw inflate with a single call using a call-back 1034 interface for input and output. This is potentially more efficient than 1035 inflate() for file i/o applications, in that it avoids copying between the 1036 output and the sliding window by simply making the window itself the output 1037 buffer. inflate() can be faster on modern CPUs when used with large 1038 buffers. inflateBack() trusts the application to not change the output 1039 buffer passed by the output function, at least until inflateBack() returns. 1040 1041 inflateBackInit() must be called first to allocate the internal state 1042 and to initialize the state with the user-provided window buffer. 1043 inflateBack() may then be used multiple times to inflate a complete, raw 1044 deflate stream with each call. inflateBackEnd() is then called to free the 1045 allocated state. 1046 1047 A raw deflate stream is one with no zlib or gzip header or trailer. 1048 This routine would normally be used in a utility that reads zip or gzip 1049 files and writes out uncompressed files. The utility would decode the 1050 header and process the trailer on its own, hence this routine expects only 1051 the raw deflate stream to decompress. This is different from the normal 1052 behavior of inflate(), which expects either a zlib or gzip header and 1053 trailer around the deflate stream. 1054 1055 inflateBack() uses two subroutines supplied by the caller that are then 1056 called by inflateBack() for input and output. inflateBack() calls those 1057 routines until it reads a complete deflate stream and writes out all of the 1058 uncompressed data, or until it encounters an error. The function's 1059 parameters and return types are defined above in the in_func and out_func 1060 typedefs. inflateBack() will call in(in_desc, &buf) which should return the 1061 number of bytes of provided input, and a pointer to that input in buf. If 1062 there is no input available, in() must return zero--buf is ignored in that 1063 case--and inflateBack() will return a buffer error. inflateBack() will call 1064 out(out_desc, buf, len) to write the uncompressed data buf[0..len-1]. out() 1065 should return zero on success, or non-zero on failure. If out() returns 1066 non-zero, inflateBack() will return with an error. Neither in() nor out() 1067 are permitted to change the contents of the window provided to 1068 inflateBackInit(), which is also the buffer that out() uses to write from. 1069 The length written by out() will be at most the window size. Any non-zero 1070 amount of input may be provided by in(). 1071 1072 For convenience, inflateBack() can be provided input on the first call by 1073 setting strm->next_in and strm->avail_in. If that input is exhausted, then 1074 in() will be called. Therefore strm->next_in must be initialized before 1075 calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called 1076 immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in 1077 must also be initialized, and then if strm->avail_in is not zero, input will 1078 initially be taken from strm->next_in[0 .. strm->avail_in - 1]. 1079 1080 The in_desc and out_desc parameters of inflateBack() is passed as the 1081 first parameter of in() and out() respectively when they are called. These 1082 descriptors can be optionally used to pass any information that the caller- 1083 supplied in() and out() functions need to do their job. 1084 1085 On return, inflateBack() will set strm->next_in and strm->avail_in to 1086 pass back any unused input that was provided by the last in() call. The 1087 return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR 1088 if in() or out() returned an error, Z_DATA_ERROR if there was a format error 1089 in the deflate stream (in which case strm->msg is set to indicate the nature 1090 of the error), or Z_STREAM_ERROR if the stream was not properly initialized. 1091 In the case of Z_BUF_ERROR, an input or output error can be distinguished 1092 using strm->next_in which will be Z_NULL only if in() returned an error. If 1093 strm->next_in is not Z_NULL, then the Z_BUF_ERROR was due to out() returning 1094 non-zero. (in() will always be called before out(), so strm->next_in is 1095 assured to be defined if out() returns non-zero.) Note that inflateBack() 1096 cannot return Z_OK. 1097 */ 1098 1099 ZEXTERN int ZEXPORT inflateBackEnd OF((z_streamp strm)); 1100 /* 1101 All memory allocated by inflateBackInit() is freed. 1102 1103 inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream 1104 state was inconsistent. 1105 */ 1106 1107 ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void)); 1108 /* Return flags indicating compile-time options. 1109 1110 Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other: 1111 1.0: size of uInt 1112 3.2: size of uLong 1113 5.4: size of voidpf (pointer) 1114 7.6: size of z_off_t 1115 1116 Compiler, assembler, and debug options: 1117 8: DEBUG 1118 9: ASMV or ASMINF -- use ASM code 1119 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention 1120 11: 0 (reserved) 1121 1122 One-time table building (smaller code, but not thread-safe if true): 1123 12: BUILDFIXED -- build static block decoding tables when needed 1124 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed 1125 14,15: 0 (reserved) 1126 1127 Library content (indicates missing functionality): 1128 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking 1129 deflate code when not needed) 1130 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect 1131 and decode gzip streams (to avoid linking crc code) 1132 18-19: 0 (reserved) 1133 1134 Operation variations (changes in library functionality): 1135 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate 1136 21: FASTEST -- deflate algorithm with only one, lowest compression level 1137 22,23: 0 (reserved) 1138 1139 The sprintf variant used by gzprintf (zero is best): 1140 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format 1141 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure! 1142 26: 0 = returns value, 1 = void -- 1 means inferred string length returned 1143 1144 Remainder: 1145 27-31: 0 (reserved) 1146 */ 1147 1148 #ifndef Z_SOLO 1149 1150 /* utility functions */ 1151 1152 /* 1153 The following utility functions are implemented on top of the basic 1154 stream-oriented functions. To simplify the interface, some default options 1155 are assumed (compression level and memory usage, standard memory allocation 1156 functions). The source code of these utility functions can be modified if 1157 you need special options. 1158 */ 1159 1160 ZEXTERN int ZEXPORT compress OF((Bytef *dest, uLongf *destLen, 1161 const Bytef *source, uLong sourceLen)); 1162 /* 1163 Compresses the source buffer into the destination buffer. sourceLen is 1164 the byte length of the source buffer. Upon entry, destLen is the total size 1165 of the destination buffer, which must be at least the value returned by 1166 compressBound(sourceLen). Upon exit, destLen is the actual size of the 1167 compressed buffer. 1168 1169 compress returns Z_OK if success, Z_MEM_ERROR if there was not 1170 enough memory, Z_BUF_ERROR if there was not enough room in the output 1171 buffer. 1172 */ 1173 1174 ZEXTERN int ZEXPORT compress2 OF((Bytef *dest, uLongf *destLen, 1175 const Bytef *source, uLong sourceLen, 1176 int level)); 1177 /* 1178 Compresses the source buffer into the destination buffer. The level 1179 parameter has the same meaning as in deflateInit. sourceLen is the byte 1180 length of the source buffer. Upon entry, destLen is the total size of the 1181 destination buffer, which must be at least the value returned by 1182 compressBound(sourceLen). Upon exit, destLen is the actual size of the 1183 compressed buffer. 1184 1185 compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 1186 memory, Z_BUF_ERROR if there was not enough room in the output buffer, 1187 Z_STREAM_ERROR if the level parameter is invalid. 1188 */ 1189 1190 ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen)); 1191 /* 1192 compressBound() returns an upper bound on the compressed size after 1193 compress() or compress2() on sourceLen bytes. It would be used before a 1194 compress() or compress2() call to allocate the destination buffer. 1195 */ 1196 1197 ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen, 1198 const Bytef *source, uLong sourceLen)); 1199 /* 1200 Decompresses the source buffer into the destination buffer. sourceLen is 1201 the byte length of the source buffer. Upon entry, destLen is the total size 1202 of the destination buffer, which must be large enough to hold the entire 1203 uncompressed data. (The size of the uncompressed data must have been saved 1204 previously by the compressor and transmitted to the decompressor by some 1205 mechanism outside the scope of this compression library.) Upon exit, destLen 1206 is the actual size of the uncompressed buffer. 1207 1208 uncompress returns Z_OK if success, Z_MEM_ERROR if there was not 1209 enough memory, Z_BUF_ERROR if there was not enough room in the output 1210 buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete. In 1211 the case where there is not enough room, uncompress() will fill the output 1212 buffer with the uncompressed data up to that point. 1213 */ 1214 1215 /* gzip file access functions */ 1216 1217 /* 1218 This library supports reading and writing files in gzip (.gz) format with 1219 an interface similar to that of stdio, using the functions that start with 1220 "gz". The gzip format is different from the zlib format. gzip is a gzip 1221 wrapper, documented in RFC 1952, wrapped around a deflate stream. 1222 */ 1223 1224 typedef struct gzFile_s *gzFile; /* semi-opaque gzip file descriptor */ 1225 1226 /* 1227 ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode)); 1228 1229 Opens a gzip (.gz) file for reading or writing. The mode parameter is as 1230 in fopen ("rb" or "wb") but can also include a compression level ("wb9") or 1231 a strategy: 'f' for filtered data as in "wb6f", 'h' for Huffman-only 1232 compression as in "wb1h", 'R' for run-length encoding as in "wb1R", or 'F' 1233 for fixed code compression as in "wb9F". (See the description of 1234 deflateInit2 for more information about the strategy parameter.) 'T' will 1235 request transparent writing or appending with no compression and not using 1236 the gzip format. 1237 1238 "a" can be used instead of "w" to request that the gzip stream that will 1239 be written be appended to the file. "+" will result in an error, since 1240 reading and writing to the same gzip file is not supported. The addition of 1241 "x" when writing will create the file exclusively, which fails if the file 1242 already exists. On systems that support it, the addition of "e" when 1243 reading or writing will set the flag to close the file on an execve() call. 1244 1245 These functions, as well as gzip, will read and decode a sequence of gzip 1246 streams in a file. The append function of gzopen() can be used to create 1247 such a file. (Also see gzflush() for another way to do this.) When 1248 appending, gzopen does not test whether the file begins with a gzip stream, 1249 nor does it look for the end of the gzip streams to begin appending. gzopen 1250 will simply append a gzip stream to the existing file. 1251 1252 gzopen can be used to read a file which is not in gzip format; in this 1253 case gzread will directly read from the file without decompression. When 1254 reading, this will be detected automatically by looking for the magic two- 1255 byte gzip header. 1256 1257 gzopen returns NULL if the file could not be opened, if there was 1258 insufficient memory to allocate the gzFile state, or if an invalid mode was 1259 specified (an 'r', 'w', or 'a' was not provided, or '+' was provided). 1260 errno can be checked to determine if the reason gzopen failed was that the 1261 file could not be opened. 1262 */ 1263 1264 ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode)); 1265 /* 1266 gzdopen associates a gzFile with the file descriptor fd. File descriptors 1267 are obtained from calls like open, dup, creat, pipe or fileno (if the file 1268 has been previously opened with fopen). The mode parameter is as in gzopen. 1269 1270 The next call of gzclose on the returned gzFile will also close the file 1271 descriptor fd, just like fclose(fdopen(fd, mode)) closes the file descriptor 1272 fd. If you want to keep fd open, use fd = dup(fd_keep); gz = gzdopen(fd, 1273 mode);. The duplicated descriptor should be saved to avoid a leak, since 1274 gzdopen does not close fd if it fails. If you are using fileno() to get the 1275 file descriptor from a FILE *, then you will have to use dup() to avoid 1276 double-close()ing the file descriptor. Both gzclose() and fclose() will 1277 close the associated file descriptor, so they need to have different file 1278 descriptors. 1279 1280 gzdopen returns NULL if there was insufficient memory to allocate the 1281 gzFile state, if an invalid mode was specified (an 'r', 'w', or 'a' was not 1282 provided, or '+' was provided), or if fd is -1. The file descriptor is not 1283 used until the next gz* read, write, seek, or close operation, so gzdopen 1284 will not detect if fd is invalid (unless fd is -1). 1285 */ 1286 1287 ZEXTERN int ZEXPORT gzbuffer OF((gzFile file, unsigned size)); 1288 /* 1289 Set the internal buffer size used by this library's functions. The 1290 default buffer size is 8192 bytes. This function must be called after 1291 gzopen() or gzdopen(), and before any other calls that read or write the 1292 file. The buffer memory allocation is always deferred to the first read or 1293 write. Two buffers are allocated, either both of the specified size when 1294 writing, or one of the specified size and the other twice that size when 1295 reading. A larger buffer size of, for example, 64K or 128K bytes will 1296 noticeably increase the speed of decompression (reading). 1297 1298 The new buffer size also affects the maximum length for gzprintf(). 1299 1300 gzbuffer() returns 0 on success, or -1 on failure, such as being called 1301 too late. 1302 */ 1303 1304 ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy)); 1305 /* 1306 Dynamically update the compression level or strategy. See the description 1307 of deflateInit2 for the meaning of these parameters. 1308 1309 gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not 1310 opened for writing. 1311 */ 1312 1313 ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len)); 1314 /* 1315 Reads the given number of uncompressed bytes from the compressed file. If 1316 the input file is not in gzip format, gzread copies the given number of 1317 bytes into the buffer directly from the file. 1318 1319 After reaching the end of a gzip stream in the input, gzread will continue 1320 to read, looking for another gzip stream. Any number of gzip streams may be 1321 concatenated in the input file, and will all be decompressed by gzread(). 1322 If something other than a gzip stream is encountered after a gzip stream, 1323 that remaining trailing garbage is ignored (and no error is returned). 1324 1325 gzread can be used to read a gzip file that is being concurrently written. 1326 Upon reaching the end of the input, gzread will return with the available 1327 data. If the error code returned by gzerror is Z_OK or Z_BUF_ERROR, then 1328 gzclearerr can be used to clear the end of file indicator in order to permit 1329 gzread to be tried again. Z_OK indicates that a gzip stream was completed 1330 on the last gzread. Z_BUF_ERROR indicates that the input file ended in the 1331 middle of a gzip stream. Note that gzread does not return -1 in the event 1332 of an incomplete gzip stream. This error is deferred until gzclose(), which 1333 will return Z_BUF_ERROR if the last gzread ended in the middle of a gzip 1334 stream. Alternatively, gzerror can be used before gzclose to detect this 1335 case. 1336 1337 gzread returns the number of uncompressed bytes actually read, less than 1338 len for end of file, or -1 for error. 1339 */ 1340 1341 ZEXTERN int ZEXPORT gzwrite OF((gzFile file, 1342 voidpc buf, unsigned len)); 1343 /* 1344 Writes the given number of uncompressed bytes into the compressed file. 1345 gzwrite returns the number of uncompressed bytes written or 0 in case of 1346 error. 1347 */ 1348 1349 ZEXTERN int ZEXPORTVA gzprintf Z_ARG((gzFile file, const char *format, ...)); 1350 /* 1351 Converts, formats, and writes the arguments to the compressed file under 1352 control of the format string, as in fprintf. gzprintf returns the number of 1353 uncompressed bytes actually written, or 0 in case of error. The number of 1354 uncompressed bytes written is limited to 8191, or one less than the buffer 1355 size given to gzbuffer(). The caller should assure that this limit is not 1356 exceeded. If it is exceeded, then gzprintf() will return an error (0) with 1357 nothing written. In this case, there may also be a buffer overflow with 1358 unpredictable consequences, which is possible only if zlib was compiled with 1359 the insecure functions sprintf() or vsprintf() because the secure snprintf() 1360 or vsnprintf() functions were not available. This can be determined using 1361 zlibCompileFlags(). 1362 */ 1363 1364 ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s)); 1365 /* 1366 Writes the given null-terminated string to the compressed file, excluding 1367 the terminating null character. 1368 1369 gzputs returns the number of characters written, or -1 in case of error. 1370 */ 1371 1372 ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len)); 1373 /* 1374 Reads bytes from the compressed file until len-1 characters are read, or a 1375 newline character is read and transferred to buf, or an end-of-file 1376 condition is encountered. If any characters are read or if len == 1, the 1377 string is terminated with a null character. If no characters are read due 1378 to an end-of-file or len < 1, then the buffer is left untouched. 1379 1380 gzgets returns buf which is a null-terminated string, or it returns NULL 1381 for end-of-file or in case of error. If there was an error, the contents at 1382 buf are indeterminate. 1383 */ 1384 1385 ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c)); 1386 /* 1387 Writes c, converted to an unsigned char, into the compressed file. gzputc 1388 returns the value that was written, or -1 in case of error. 1389 */ 1390 1391 ZEXTERN int ZEXPORT gzgetc OF((gzFile file)); 1392 /* 1393 Reads one byte from the compressed file. gzgetc returns this byte or -1 1394 in case of end of file or error. This is implemented as a macro for speed. 1395 As such, it does not do all of the checking the other functions do. I.e. 1396 it does not check to see if file is NULL, nor whether the structure file 1397 points to has been clobbered or not. 1398 */ 1399 1400 ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file)); 1401 /* 1402 Push one character back onto the stream to be read as the first character 1403 on the next read. At least one character of push-back is allowed. 1404 gzungetc() returns the character pushed, or -1 on failure. gzungetc() will 1405 fail if c is -1, and may fail if a character has been pushed but not read 1406 yet. If gzungetc is used immediately after gzopen or gzdopen, at least the 1407 output buffer size of pushed characters is allowed. (See gzbuffer above.) 1408 The pushed character will be discarded if the stream is repositioned with 1409 gzseek() or gzrewind(). 1410 */ 1411 1412 ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush)); 1413 /* 1414 Flushes all pending output into the compressed file. The parameter flush 1415 is as in the deflate() function. The return value is the zlib error number 1416 (see function gzerror below). gzflush is only permitted when writing. 1417 1418 If the flush parameter is Z_FINISH, the remaining data is written and the 1419 gzip stream is completed in the output. If gzwrite() is called again, a new 1420 gzip stream will be started in the output. gzread() is able to read such 1421 concatented gzip streams. 1422 1423 gzflush should be called only when strictly necessary because it will 1424 degrade compression if called too often. 1425 */ 1426 1427 /* 1428 ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file, 1429 z_off_t offset, int whence)); 1430 1431 Sets the starting position for the next gzread or gzwrite on the given 1432 compressed file. The offset represents a number of bytes in the 1433 uncompressed data stream. The whence parameter is defined as in lseek(2); 1434 the value SEEK_END is not supported. 1435 1436 If the file is opened for reading, this function is emulated but can be 1437 extremely slow. If the file is opened for writing, only forward seeks are 1438 supported; gzseek then compresses a sequence of zeroes up to the new 1439 starting position. 1440 1441 gzseek returns the resulting offset location as measured in bytes from 1442 the beginning of the uncompressed stream, or -1 in case of error, in 1443 particular if the file is opened for writing and the new starting position 1444 would be before the current position. 1445 */ 1446 1447 ZEXTERN int ZEXPORT gzrewind OF((gzFile file)); 1448 /* 1449 Rewinds the given file. This function is supported only for reading. 1450 1451 gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET) 1452 */ 1453 1454 /* 1455 ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file)); 1456 1457 Returns the starting position for the next gzread or gzwrite on the given 1458 compressed file. This position represents a number of bytes in the 1459 uncompressed data stream, and is zero when starting, even if appending or 1460 reading a gzip stream from the middle of a file using gzdopen(). 1461 1462 gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR) 1463 */ 1464 1465 /* 1466 ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile file)); 1467 1468 Returns the current offset in the file being read or written. This offset 1469 includes the count of bytes that precede the gzip stream, for example when 1470 appending or when using gzdopen() for reading. When reading, the offset 1471 does not include as yet unused buffered input. This information can be used 1472 for a progress indicator. On error, gzoffset() returns -1. 1473 */ 1474 1475 ZEXTERN int ZEXPORT gzeof OF((gzFile file)); 1476 /* 1477 Returns true (1) if the end-of-file indicator has been set while reading, 1478 false (0) otherwise. Note that the end-of-file indicator is set only if the 1479 read tried to go past the end of the input, but came up short. Therefore, 1480 just like feof(), gzeof() may return false even if there is no more data to 1481 read, in the event that the last read request was for the exact number of 1482 bytes remaining in the input file. This will happen if the input file size 1483 is an exact multiple of the buffer size. 1484 1485 If gzeof() returns true, then the read functions will return no more data, 1486 unless the end-of-file indicator is reset by gzclearerr() and the input file 1487 has grown since the previous end of file was detected. 1488 */ 1489 1490 ZEXTERN int ZEXPORT gzdirect OF((gzFile file)); 1491 /* 1492 Returns true (1) if file is being copied directly while reading, or false 1493 (0) if file is a gzip stream being decompressed. 1494 1495 If the input file is empty, gzdirect() will return true, since the input 1496 does not contain a gzip stream. 1497 1498 If gzdirect() is used immediately after gzopen() or gzdopen() it will 1499 cause buffers to be allocated to allow reading the file to determine if it 1500 is a gzip file. Therefore if gzbuffer() is used, it should be called before 1501 gzdirect(). 1502 1503 When writing, gzdirect() returns true (1) if transparent writing was 1504 requested ("wT" for the gzopen() mode), or false (0) otherwise. (Note: 1505 gzdirect() is not needed when writing. Transparent writing must be 1506 explicitly requested, so the application already knows the answer. When 1507 linking statically, using gzdirect() will include all of the zlib code for 1508 gzip file reading and decompression, which may not be desired.) 1509 */ 1510 1511 ZEXTERN int ZEXPORT gzclose OF((gzFile file)); 1512 /* 1513 Flushes all pending output if necessary, closes the compressed file and 1514 deallocates the (de)compression state. Note that once file is closed, you 1515 cannot call gzerror with file, since its structures have been deallocated. 1516 gzclose must not be called more than once on the same file, just as free 1517 must not be called more than once on the same allocation. 1518 1519 gzclose will return Z_STREAM_ERROR if file is not valid, Z_ERRNO on a 1520 file operation error, Z_MEM_ERROR if out of memory, Z_BUF_ERROR if the 1521 last read ended in the middle of a gzip stream, or Z_OK on success. 1522 */ 1523 1524 ZEXTERN int ZEXPORT gzclose_r OF((gzFile file)); 1525 ZEXTERN int ZEXPORT gzclose_w OF((gzFile file)); 1526 /* 1527 Same as gzclose(), but gzclose_r() is only for use when reading, and 1528 gzclose_w() is only for use when writing or appending. The advantage to 1529 using these instead of gzclose() is that they avoid linking in zlib 1530 compression or decompression code that is not used when only reading or only 1531 writing respectively. If gzclose() is used, then both compression and 1532 decompression code will be included the application when linking to a static 1533 zlib library. 1534 */ 1535 1536 ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum)); 1537 /* 1538 Returns the error message for the last error which occurred on the given 1539 compressed file. errnum is set to zlib error number. If an error occurred 1540 in the file system and not in the compression library, errnum is set to 1541 Z_ERRNO and the application may consult errno to get the exact error code. 1542 1543 The application must not modify the returned string. Future calls to 1544 this function may invalidate the previously returned string. If file is 1545 closed, then the string previously returned by gzerror will no longer be 1546 available. 1547 1548 gzerror() should be used to distinguish errors from end-of-file for those 1549 functions above that do not distinguish those cases in their return values. 1550 */ 1551 1552 ZEXTERN void ZEXPORT gzclearerr OF((gzFile file)); 1553 /* 1554 Clears the error and end-of-file flags for file. This is analogous to the 1555 clearerr() function in stdio. This is useful for continuing to read a gzip 1556 file that is being written concurrently. 1557 */ 1558 1559 #endif /* !Z_SOLO */ 1560 1561 /* checksum functions */ 1562 1563 /* 1564 These functions are not related to compression but are exported 1565 anyway because they might be useful in applications using the compression 1566 library. 1567 */ 1568 1569 ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len)); 1570 /* 1571 Update a running Adler-32 checksum with the bytes buf[0..len-1] and 1572 return the updated checksum. If buf is Z_NULL, this function returns the 1573 required initial value for the checksum. 1574 1575 An Adler-32 checksum is almost as reliable as a CRC32 but can be computed 1576 much faster. 1577 1578 Usage example: 1579 1580 uLong adler = adler32(0L, Z_NULL, 0); 1581 1582 while (read_buffer(buffer, length) != EOF) { 1583 adler = adler32(adler, buffer, length); 1584 } 1585 if (adler != original_adler) error(); 1586 */ 1587 1588 /* 1589 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong adler1, uLong adler2, 1590 z_off_t len2)); 1591 1592 Combine two Adler-32 checksums into one. For two sequences of bytes, seq1 1593 and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for 1594 each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of 1595 seq1 and seq2 concatenated, requiring only adler1, adler2, and len2. Note 1596 that the z_off_t type (like off_t) is a signed integer. If len2 is 1597 negative, the result has no meaning or utility. 1598 */ 1599 1600 ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len)); 1601 /* 1602 Update a running CRC-32 with the bytes buf[0..len-1] and return the 1603 updated CRC-32. If buf is Z_NULL, this function returns the required 1604 initial value for the crc. Pre- and post-conditioning (one's complement) is 1605 performed within this function so it shouldn't be done by the application. 1606 1607 Usage example: 1608 1609 uLong crc = crc32(0L, Z_NULL, 0); 1610 1611 while (read_buffer(buffer, length) != EOF) { 1612 crc = crc32(crc, buffer, length); 1613 } 1614 if (crc != original_crc) error(); 1615 */ 1616 1617 /* 1618 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2)); 1619 1620 Combine two CRC-32 check values into one. For two sequences of bytes, 1621 seq1 and seq2 with lengths len1 and len2, CRC-32 check values were 1622 calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32 1623 check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and 1624 len2. 1625 */ 1626 1627 1628 /* various hacks, don't look :) */ 1629 1630 /* deflateInit and inflateInit are macros to allow checking the zlib version 1631 * and the compiler's view of z_stream: 1632 */ 1633 ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level, 1634 const char *version, int stream_size)); 1635 ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm, 1636 const char *version, int stream_size)); 1637 ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method, 1638 int windowBits, int memLevel, 1639 int strategy, const char *version, 1640 int stream_size)); 1641 ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits, 1642 const char *version, int stream_size)); 1643 ZEXTERN int ZEXPORT inflateBackInit_ OF((z_streamp strm, int windowBits, 1644 unsigned char FAR *window, 1645 const char *version, 1646 int stream_size)); 1647 #define deflateInit(strm, level) \ 1648 deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream)) 1649 #define inflateInit(strm) \ 1650 inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream)) 1651 #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \ 1652 deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\ 1653 (strategy), ZLIB_VERSION, (int)sizeof(z_stream)) 1654 #define inflateInit2(strm, windowBits) \ 1655 inflateInit2_((strm), (windowBits), ZLIB_VERSION, \ 1656 (int)sizeof(z_stream)) 1657 #define inflateBackInit(strm, windowBits, window) \ 1658 inflateBackInit_((strm), (windowBits), (window), \ 1659 ZLIB_VERSION, (int)sizeof(z_stream)) 1660 1661 #ifndef Z_SOLO 1662 1663 /* gzgetc() macro and its supporting function and exposed data structure. Note 1664 * that the real internal state is much larger than the exposed structure. 1665 * This abbreviated structure exposes just enough for the gzgetc() macro. The 1666 * user should not mess with these exposed elements, since their names or 1667 * behavior could change in the future, perhaps even capriciously. They can 1668 * only be used by the gzgetc() macro. You have been warned. 1669 */ 1670 struct gzFile_s { 1671 unsigned have; 1672 unsigned char *next; 1673 z_off64_t pos; 1674 }; 1675 ZEXTERN int ZEXPORT gzgetc_ OF((gzFile file)); /* backward compatibility */ 1676 #ifdef Z_PREFIX_SET 1677 # undef z_gzgetc 1678 # define z_gzgetc(g) \ 1679 ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : gzgetc(g)) 1680 #else 1681 # define gzgetc(g) \ 1682 ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : gzgetc(g)) 1683 #endif 1684 1685 /* provide 64-bit offset functions if _LARGEFILE64_SOURCE defined, and/or 1686 * change the regular functions to 64 bits if _FILE_OFFSET_BITS is 64 (if 1687 * both are true, the application gets the *64 functions, and the regular 1688 * functions are changed to 64 bits) -- in case these are set on systems 1689 * without large file support, _LFS64_LARGEFILE must also be true 1690 */ 1691 #ifdef Z_LARGE64 1692 ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *)); 1693 ZEXTERN z_off64_t ZEXPORT gzseek64 OF((gzFile, z_off64_t, int)); 1694 ZEXTERN z_off64_t ZEXPORT gztell64 OF((gzFile)); 1695 ZEXTERN z_off64_t ZEXPORT gzoffset64 OF((gzFile)); 1696 ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off64_t)); 1697 ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off64_t)); 1698 #endif 1699 1700 #if !defined(ZLIB_INTERNAL) && defined(Z_WANT64) 1701 # ifdef Z_PREFIX_SET 1702 # define z_gzopen z_gzopen64 1703 # define z_gzseek z_gzseek64 1704 # define z_gztell z_gztell64 1705 # define z_gzoffset z_gzoffset64 1706 # define z_adler32_combine z_adler32_combine64 1707 # define z_crc32_combine z_crc32_combine64 1708 # else 1709 # define gzopen gzopen64 1710 # define gzseek gzseek64 1711 # define gztell gztell64 1712 # define gzoffset gzoffset64 1713 # define adler32_combine adler32_combine64 1714 # define crc32_combine crc32_combine64 1715 # endif 1716 # ifndef Z_LARGE64 1717 ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *)); 1718 ZEXTERN z_off_t ZEXPORT gzseek64 OF((gzFile, z_off_t, int)); 1719 ZEXTERN z_off_t ZEXPORT gztell64 OF((gzFile)); 1720 ZEXTERN z_off_t ZEXPORT gzoffset64 OF((gzFile)); 1721 ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off_t)); 1722 ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off_t)); 1723 # endif 1724 #else 1725 ZEXTERN gzFile ZEXPORT gzopen OF((const char *, const char *)); 1726 ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile, z_off_t, int)); 1727 ZEXTERN z_off_t ZEXPORT gztell OF((gzFile)); 1728 ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile)); 1729 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t)); 1730 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t)); 1731 #endif 1732 1733 #else /* Z_SOLO */ 1734 1735 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t)); 1736 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t)); 1737 1738 #endif /* !Z_SOLO */ 1739 1740 /* hack for buggy compilers */ 1741 #if !defined(ZUTIL_H) && !defined(NO_DUMMY_DECL) 1742 struct internal_state {int dummy;}; 1743 #endif 1744 1745 /* undocumented functions */ 1746 ZEXTERN const char * ZEXPORT zError OF((int)); 1747 ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp)); 1748 ZEXTERN const z_crc_t FAR * ZEXPORT get_crc_table OF((void)); 1749 ZEXTERN int ZEXPORT inflateUndermine OF((z_streamp, int)); 1750 ZEXTERN int ZEXPORT inflateResetKeep OF((z_streamp)); 1751 ZEXTERN int ZEXPORT deflateResetKeep OF((z_streamp)); 1752 #if defined(_WIN32) && !defined(Z_SOLO) 1753 ZEXTERN gzFile ZEXPORT gzopen_w OF((const wchar_t *path, 1754 const char *mode)); 1755 #endif 1756 #if defined(STDC) || defined(Z_HAVE_STDARG_H) 1757 # ifndef Z_SOLO 1758 ZEXTERN int ZEXPORTVA gzvprintf Z_ARG((gzFile file, 1759 const char *format, 1760 va_list va)); 1761 # endif 1762 #endif 1763 1764 #ifdef __cplusplus 1765 } 1766 #endif 1767 1768 #endif /* ZLIB_H */ 1769