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 #ifdef _MSC_VER 35 #define _CRT_SECURE_NO_WARNINGS 36 #endif 37 38 #define deflate_copyright FPDFAPI_deflate_copyright 39 #define adler32 FPDFAPI_adler32 40 #define compress2 FPDFAPI_compress2 41 #define compress FPDFAPI_compress 42 #define compressBound FPDFAPI_compressBound 43 #define get_crc_table FPDFAPI_get_crc_table 44 #define crc32 FPDFAPI_crc32 45 #define deflateInit_ FPDFAPI_deflateInit_ 46 #define deflateInit2_ FPDFAPI_deflateInit2_ 47 #define deflateSetDictionary FPDFAPI_deflateSetDictionary 48 #define deflateReset FPDFAPI_deflateReset 49 #define deflatePending FPDFAPI_deflatePending 50 #define deflatePrime FPDFAPI_deflatePrime 51 #define deflateParams FPDFAPI_deflateParams 52 #define deflateBound FPDFAPI_deflateBound 53 #define deflateSetHeader FPDFAPI_deflateSetHeader 54 #define deflateTune FPDFAPI_deflateTune 55 #define deflate FPDFAPI_deflate 56 #define deflateEnd FPDFAPI_deflateEnd 57 #define deflateCopy FPDFAPI_deflateCopy 58 #define inflateBackInit_ FPDFAPI_inflateBackInit_ 59 #define inflateBack FPDFAPI_inflateBack 60 #define inflateBackEnd FPDFAPI_inflateBackEnd 61 #define inflateReset FPDFAPI_inflateReset 62 #define inflateInit2_ FPDFAPI_inflateInit2_ 63 #define inflateInit_ FPDFAPI_inflateInit_ 64 #define inflate FPDFAPI_inflate 65 #define inflateEnd FPDFAPI_inflateEnd 66 #define inflateSetDictionary FPDFAPI_inflateSetDictionary 67 #define inflateSync FPDFAPI_inflateSync 68 #define inflateSyncPoint FPDFAPI_inflateSyncPoint 69 #define inflateCopy FPDFAPI_inflateCopy 70 #define uncompress FPDFAPI_uncompress 71 #define zlibVersion FPDFAPI_zlibVersion 72 #define zlibCompileFlags FPDFAPI_zlibCompileFlags 73 #define zError FPDFAPI_zError 74 #define z_errmsg FPDFAPI_z_errmsg 75 #define zcfree FPDFAPI_zcfree 76 #define zcalloc FPDFAPI_zcalloc 77 #define inflate_fast FPDFAPI_inflate_fast 78 #define inflate_table FPDFAPI_inflate_table 79 #define inflate_copyright FPDFAPI_inflate_copyright 80 #define _length_code FPDFAPI_length_code 81 #define _tr_flush_block FPDFAPI_tr_flush_block 82 #define _dist_code FPDFAPI_dist_code 83 #define _tr_stored_block FPDFAPI_tr_stored_block 84 #define _tr_init FPDFAPI_tr_init 85 #define _tr_align FPDFAPI_tr_align 86 #define _tr_tally FPDFAPI_tr_tally 87 #define _tr_flush_bits FPDFAPI_tr_flush_bits 88 #define adler32_combine FPDFAPI_adler32_combine 89 #define inflatePrime FPDFAPI_inflatePrime 90 #define inflateGetDictionary FPDFAPI_inflateGetDictionary 91 #define inflateGetHeader FPDFAPI_inflateGetHeader 92 #define crc32_combine FPDFAPI_crc32_combine 93 #define inflateReset2 FPDFAPI_inflateReset2 94 #define inflateUndermine FPDFAPI_inflateUndermine 95 #define inflateMark FPDFAPI_inflateMark 96 #define adler32_combine64 FPDFAPI_adler32_combine64 97 #define inflateResetKeep FPDFAPI_inflateResetKeep 98 #define deflateResetKeep FPDFAPI_deflateResetKeep 99 100 #include "zconf.h" 101 102 /* Sunliang.Liu 20100908 sync the config to the old revision. NO_GZIP */ 103 #define NO_GZIP /* XYQ */ 104 105 #ifdef __cplusplus 106 extern "C" { 107 #endif 108 109 #define ZLIB_VERSION "1.2.8" 110 #define ZLIB_VERNUM 0x1280 111 #define ZLIB_VER_MAJOR 1 112 #define ZLIB_VER_MINOR 2 113 #define ZLIB_VER_REVISION 8 114 #define ZLIB_VER_SUBREVISION 0 115 116 /* 117 The 'zlib' compression library provides in-memory compression and 118 decompression functions, including integrity checks of the uncompressed data. 119 This version of the library supports only one compression method (deflation) 120 but other algorithms will be added later and will have the same stream 121 interface. 122 123 Compression can be done in a single step if the buffers are large enough, 124 or can be done by repeated calls of the compression function. In the latter 125 case, the application must provide more input and/or consume the output 126 (providing more output space) before each call. 127 128 The compressed data format used by default by the in-memory functions is 129 the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped 130 around a deflate stream, which is itself documented in RFC 1951. 131 132 The library also supports reading and writing files in gzip (.gz) format 133 with an interface similar to that of stdio using the functions that start 134 with "gz". The gzip format is different from the zlib format. gzip is a 135 gzip wrapper, documented in RFC 1952, wrapped around a deflate stream. 136 137 This library can optionally read and write gzip streams in memory as well. 138 139 The zlib format was designed to be compact and fast for use in memory 140 and on communications channels. The gzip format was designed for single- 141 file compression on file systems, has a larger header than zlib to maintain 142 directory information, and uses a different, slower check method than zlib. 143 144 The library does not install any signal handler. The decoder checks 145 the consistency of the compressed data, so the library should never crash 146 even in case of corrupted input. 147 */ 148 149 typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size)); 150 typedef void (*free_func) OF((voidpf opaque, voidpf address)); 151 152 struct internal_state; 153 154 typedef struct z_stream_s { 155 z_const Bytef *next_in; /* next input byte */ 156 uInt avail_in; /* number of bytes available at next_in */ 157 uLong total_in; /* total number of input bytes read so far */ 158 159 Bytef *next_out; /* next output byte should be put there */ 160 uInt avail_out; /* remaining free space at next_out */ 161 uLong total_out; /* total number of bytes output so far */ 162 163 z_const char *msg; /* last error message, NULL if no error */ 164 struct internal_state FAR *state; /* not visible by applications */ 165 166 alloc_func zalloc; /* used to allocate the internal state */ 167 free_func zfree; /* used to free the internal state */ 168 voidpf opaque; /* private data object passed to zalloc and zfree */ 169 170 int data_type; /* best guess about the data type: binary or text */ 171 uLong adler; /* adler32 value of the uncompressed data */ 172 uLong reserved; /* reserved for future use */ 173 } z_stream; 174 175 typedef z_stream FAR *z_streamp; 176 177 /* 178 gzip header information passed to and from zlib routines. See RFC 1952 179 for more details on the meanings of these fields. 180 */ 181 typedef struct gz_header_s { 182 int text; /* true if compressed data believed to be text */ 183 uLong time; /* modification time */ 184 int xflags; /* extra flags (not used when writing a gzip file) */ 185 int os; /* operating system */ 186 Bytef *extra; /* pointer to extra field or Z_NULL if none */ 187 uInt extra_len; /* extra field length (valid if extra != Z_NULL) */ 188 uInt extra_max; /* space at extra (only when reading header) */ 189 Bytef *name; /* pointer to zero-terminated file name or Z_NULL */ 190 uInt name_max; /* space at name (only when reading header) */ 191 Bytef *comment; /* pointer to zero-terminated comment or Z_NULL */ 192 uInt comm_max; /* space at comment (only when reading header) */ 193 int hcrc; /* true if there was or will be a header crc */ 194 int done; /* true when done reading gzip header (not used 195 when writing a gzip file) */ 196 } gz_header; 197 198 typedef gz_header FAR *gz_headerp; 199 200 /* 201 The application must update next_in and avail_in when avail_in has dropped 202 to zero. It must update next_out and avail_out when avail_out has dropped 203 to zero. The application must initialize zalloc, zfree and opaque before 204 calling the init function. All other fields are set by the compression 205 library and must not be updated by the application. 206 207 The opaque value provided by the application will be passed as the first 208 parameter for calls of zalloc and zfree. This can be useful for custom 209 memory management. The compression library attaches no meaning to the 210 opaque value. 211 212 zalloc must return Z_NULL if there is not enough memory for the object. 213 If zlib is used in a multi-threaded application, zalloc and zfree must be 214 thread safe. 215 216 On 16-bit systems, the functions zalloc and zfree must be able to allocate 217 exactly 65536 bytes, but will not be required to allocate more than this if 218 the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, pointers 219 returned by zalloc for objects of exactly 65536 bytes *must* have their 220 offset normalized to zero. The default allocation function provided by this 221 library ensures this (see zutil.c). To reduce memory requirements and avoid 222 any allocation of 64K objects, at the expense of compression ratio, compile 223 the library with -DMAX_WBITS=14 (see zconf.h). 224 225 The fields total_in and total_out can be used for statistics or progress 226 reports. After compression, total_in holds the total size of the 227 uncompressed data and may be saved for use in the decompressor (particularly 228 if the decompressor wants to decompress everything in a single step). 229 */ 230 231 /* constants */ 232 233 #define Z_NO_FLUSH 0 234 #define Z_PARTIAL_FLUSH 1 235 #define Z_SYNC_FLUSH 2 236 #define Z_FULL_FLUSH 3 237 #define Z_FINISH 4 238 #define Z_BLOCK 5 239 #define Z_TREES 6 240 /* Allowed flush values; see deflate() and inflate() below for details */ 241 242 #define Z_OK 0 243 #define Z_STREAM_END 1 244 #define Z_NEED_DICT 2 245 #define Z_ERRNO (-1) 246 #define Z_STREAM_ERROR (-2) 247 #define Z_DATA_ERROR (-3) 248 #define Z_MEM_ERROR (-4) 249 #define Z_BUF_ERROR (-5) 250 #define Z_VERSION_ERROR (-6) 251 /* Return codes for the compression/decompression functions. Negative values 252 * are errors, positive values are used for special but normal events. 253 */ 254 255 #define Z_NO_COMPRESSION 0 256 #define Z_BEST_SPEED 1 257 #define Z_BEST_COMPRESSION 9 258 #define Z_DEFAULT_COMPRESSION (-1) 259 /* compression levels */ 260 261 #define Z_FILTERED 1 262 #define Z_HUFFMAN_ONLY 2 263 #define Z_RLE 3 264 #define Z_FIXED 4 265 #define Z_DEFAULT_STRATEGY 0 266 /* compression strategy; see deflateInit2() below for details */ 267 268 #define Z_BINARY 0 269 #define Z_TEXT 1 270 #define Z_ASCII Z_TEXT /* for compatibility with 1.2.2 and earlier */ 271 #define Z_UNKNOWN 2 272 /* Possible values of the data_type field (though see inflate()) */ 273 274 #define Z_DEFLATED 8 275 /* The deflate compression method (the only one supported in this version) */ 276 277 #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */ 278 279 #define zlib_version zlibVersion() 280 /* for compatibility with versions < 1.0.2 */ 281 282 283 /* basic functions */ 284 285 ZEXTERN const char * ZEXPORT zlibVersion OF((void)); 286 /* The application can compare zlibVersion and ZLIB_VERSION for consistency. 287 If the first character differs, the library code actually used is not 288 compatible with the zlib.h header file used by the application. This check 289 is automatically made by deflateInit and inflateInit. 290 */ 291 292 /* 293 ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level)); 294 295 Initializes the internal stream state for compression. The fields 296 zalloc, zfree and opaque must be initialized before by the caller. If 297 zalloc and zfree are set to Z_NULL, deflateInit updates them to use default 298 allocation functions. 299 300 The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9: 301 1 gives best speed, 9 gives best compression, 0 gives no compression at all 302 (the input data is simply copied a block at a time). Z_DEFAULT_COMPRESSION 303 requests a default compromise between speed and compression (currently 304 equivalent to level 6). 305 306 deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough 307 memory, Z_STREAM_ERROR if level is not a valid compression level, or 308 Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible 309 with the version assumed by the caller (ZLIB_VERSION). msg is set to null 310 if there is no error message. deflateInit does not perform any compression: 311 this will be done by deflate(). 312 */ 313 314 315 ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush)); 316 /* 317 deflate compresses as much data as possible, and stops when the input 318 buffer becomes empty or the output buffer becomes full. It may introduce 319 some output latency (reading input without producing any output) except when 320 forced to flush. 321 322 The detailed semantics are as follows. deflate performs one or both of the 323 following actions: 324 325 - Compress more input starting at next_in and update next_in and avail_in 326 accordingly. If not all input can be processed (because there is not 327 enough room in the output buffer), next_in and avail_in are updated and 328 processing will resume at this point for the next call of deflate(). 329 330 - Provide more output starting at next_out and update next_out and avail_out 331 accordingly. This action is forced if the parameter flush is non zero. 332 Forcing flush frequently degrades the compression ratio, so this parameter 333 should be set only when necessary (in interactive applications). Some 334 output may be provided even if flush is not set. 335 336 Before the call of deflate(), the application should ensure that at least 337 one of the actions is possible, by providing more input and/or consuming more 338 output, and updating avail_in or avail_out accordingly; avail_out should 339 never be zero before the call. The application can consume the compressed 340 output when it wants, for example when the output buffer is full (avail_out 341 == 0), or after each call of deflate(). If deflate returns Z_OK and with 342 zero avail_out, it must be called again after making room in the output 343 buffer because there might be more output pending. 344 345 Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to 346 decide how much data to accumulate before producing output, in order to 347 maximize compression. 348 349 If the parameter flush is set to Z_SYNC_FLUSH, all pending output is 350 flushed to the output buffer and the output is aligned on a byte boundary, so 351 that the decompressor can get all input data available so far. (In 352 particular avail_in is zero after the call if enough output space has been 353 provided before the call.) Flushing may degrade compression for some 354 compression algorithms and so it should be used only when necessary. This 355 completes the current deflate block and follows it with an empty stored block 356 that is three bits plus filler bits to the next byte, followed by four bytes 357 (00 00 ff ff). 358 359 If flush is set to Z_PARTIAL_FLUSH, all pending output is flushed to the 360 output buffer, but the output is not aligned to a byte boundary. All of the 361 input data so far will be available to the decompressor, as for Z_SYNC_FLUSH. 362 This completes the current deflate block and follows it with an empty fixed 363 codes block that is 10 bits long. This assures that enough bytes are output 364 in order for the decompressor to finish the block before the empty fixed code 365 block. 366 367 If flush is set to Z_BLOCK, a deflate block is completed and emitted, as 368 for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to 369 seven bits of the current block are held to be written as the next byte after 370 the next deflate block is completed. In this case, the decompressor may not 371 be provided enough bits at this point in order to complete decompression of 372 the data provided so far to the compressor. It may need to wait for the next 373 block to be emitted. This is for advanced applications that need to control 374 the emission of deflate blocks. 375 376 If flush is set to Z_FULL_FLUSH, all output is flushed as with 377 Z_SYNC_FLUSH, and the compression state is reset so that decompression can 378 restart from this point if previous compressed data has been damaged or if 379 random access is desired. Using Z_FULL_FLUSH too often can seriously degrade 380 compression. 381 382 If deflate returns with avail_out == 0, this function must be called again 383 with the same value of the flush parameter and more output space (updated 384 avail_out), until the flush is complete (deflate returns with non-zero 385 avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that 386 avail_out is greater than six to avoid repeated flush markers due to 387 avail_out == 0 on return. 388 389 If the parameter flush is set to Z_FINISH, pending input is processed, 390 pending output is flushed and deflate returns with Z_STREAM_END if there was 391 enough output space; if deflate returns with Z_OK, this function must be 392 called again with Z_FINISH and more output space (updated avail_out) but no 393 more input data, until it returns with Z_STREAM_END or an error. After 394 deflate has returned Z_STREAM_END, the only possible operations on the stream 395 are deflateReset or deflateEnd. 396 397 Z_FINISH can be used immediately after deflateInit if all the compression 398 is to be done in a single step. In this case, avail_out must be at least the 399 value returned by deflateBound (see below). Then deflate is guaranteed to 400 return Z_STREAM_END. If not enough output space is provided, deflate will 401 not return Z_STREAM_END, and it must be called again as described above. 402 403 deflate() sets strm->adler to the adler32 checksum of all input read 404 so far (that is, total_in bytes). 405 406 deflate() may update strm->data_type if it can make a good guess about 407 the input data type (Z_BINARY or Z_TEXT). In doubt, the data is considered 408 binary. This field is only for information purposes and does not affect the 409 compression algorithm in any manner. 410 411 deflate() returns Z_OK if some progress has been made (more input 412 processed or more output produced), Z_STREAM_END if all input has been 413 consumed and all output has been produced (only when flush is set to 414 Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example 415 if next_in or next_out was Z_NULL), Z_BUF_ERROR if no progress is possible 416 (for example avail_in or avail_out was zero). Note that Z_BUF_ERROR is not 417 fatal, and deflate() can be called again with more input and more output 418 space to continue compressing. 419 */ 420 421 422 ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm)); 423 /* 424 All dynamically allocated data structures for this stream are freed. 425 This function discards any unprocessed input and does not flush any pending 426 output. 427 428 deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the 429 stream state was inconsistent, Z_DATA_ERROR if the stream was freed 430 prematurely (some input or output was discarded). In the error case, msg 431 may be set but then points to a static string (which must not be 432 deallocated). 433 */ 434 435 436 /* 437 ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm)); 438 439 Initializes the internal stream state for decompression. The fields 440 next_in, avail_in, zalloc, zfree and opaque must be initialized before by 441 the caller. If next_in is not Z_NULL and avail_in is large enough (the 442 exact value depends on the compression method), inflateInit determines the 443 compression method from the zlib header and allocates all data structures 444 accordingly; otherwise the allocation will be deferred to the first call of 445 inflate. If zalloc and zfree are set to Z_NULL, inflateInit updates them to 446 use default allocation functions. 447 448 inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough 449 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the 450 version assumed by the caller, or Z_STREAM_ERROR if the parameters are 451 invalid, such as a null pointer to the structure. msg is set to null if 452 there is no error message. inflateInit does not perform any decompression 453 apart from possibly reading the zlib header if present: actual decompression 454 will be done by inflate(). (So next_in and avail_in may be modified, but 455 next_out and avail_out are unused and unchanged.) The current implementation 456 of inflateInit() does not process any header information -- that is deferred 457 until inflate() is called. 458 */ 459 460 461 ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush)); 462 /* 463 inflate decompresses as much data as possible, and stops when the input 464 buffer becomes empty or the output buffer becomes full. It may introduce 465 some output latency (reading input without producing any output) except when 466 forced to flush. 467 468 The detailed semantics are as follows. inflate performs one or both of the 469 following actions: 470 471 - Decompress more input starting at next_in and update next_in and avail_in 472 accordingly. If not all input can be processed (because there is not 473 enough room in the output buffer), next_in is updated and processing will 474 resume at this point for the next call of inflate(). 475 476 - Provide more output starting at next_out and update next_out and avail_out 477 accordingly. inflate() provides as much output as possible, until there is 478 no more input data or no more space in the output buffer (see below about 479 the flush parameter). 480 481 Before the call of inflate(), the application should ensure that at least 482 one of the actions is possible, by providing more input and/or consuming more 483 output, and updating the next_* and avail_* values accordingly. The 484 application can consume the uncompressed output when it wants, for example 485 when the output buffer is full (avail_out == 0), or after each call of 486 inflate(). If inflate returns Z_OK and with zero avail_out, it must be 487 called again after making room in the output buffer because there might be 488 more output pending. 489 490 The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, Z_FINISH, 491 Z_BLOCK, or Z_TREES. Z_SYNC_FLUSH requests that inflate() flush as much 492 output as possible to the output buffer. Z_BLOCK requests that inflate() 493 stop if and when it gets to the next deflate block boundary. When decoding 494 the zlib or gzip format, this will cause inflate() to return immediately 495 after the header and before the first block. When doing a raw inflate, 496 inflate() will go ahead and process the first block, and will return when it 497 gets to the end of that block, or when it runs out of data. 498 499 The Z_BLOCK option assists in appending to or combining deflate streams. 500 Also to assist in this, on return inflate() will set strm->data_type to the 501 number of unused bits in the last byte taken from strm->next_in, plus 64 if 502 inflate() is currently decoding the last block in the deflate stream, plus 503 128 if inflate() returned immediately after decoding an end-of-block code or 504 decoding the complete header up to just before the first byte of the deflate 505 stream. The end-of-block will not be indicated until all of the uncompressed 506 data from that block has been written to strm->next_out. The number of 507 unused bits may in general be greater than seven, except when bit 7 of 508 data_type is set, in which case the number of unused bits will be less than 509 eight. data_type is set as noted here every time inflate() returns for all 510 flush options, and so can be used to determine the amount of currently 511 consumed input in bits. 512 513 The Z_TREES option behaves as Z_BLOCK does, but it also returns when the 514 end of each deflate block header is reached, before any actual data in that 515 block is decoded. This allows the caller to determine the length of the 516 deflate block header for later use in random access within a deflate block. 517 256 is added to the value of strm->data_type when inflate() returns 518 immediately after reaching the end of the deflate block header. 519 520 inflate() should normally be called until it returns Z_STREAM_END or an 521 error. However if all decompression is to be performed in a single step (a 522 single call of inflate), the parameter flush should be set to Z_FINISH. In 523 this case all pending input is processed and all pending output is flushed; 524 avail_out must be large enough to hold all of the uncompressed data for the 525 operation to complete. (The size of the uncompressed data may have been 526 saved by the compressor for this purpose.) The use of Z_FINISH is not 527 required to perform an inflation in one step. However it may be used to 528 inform inflate that a faster approach can be used for the single inflate() 529 call. Z_FINISH also informs inflate to not maintain a sliding window if the 530 stream completes, which reduces inflate's memory footprint. If the stream 531 does not complete, either because not all of the stream is provided or not 532 enough output space is provided, then a sliding window will be allocated and 533 inflate() can be called again to continue the operation as if Z_NO_FLUSH had 534 been used. 535 536 In this implementation, inflate() always flushes as much output as 537 possible to the output buffer, and always uses the faster approach on the 538 first call. So the effects of the flush parameter in this implementation are 539 on the return value of inflate() as noted below, when inflate() returns early 540 when Z_BLOCK or Z_TREES is used, and when inflate() avoids the allocation of 541 memory for a sliding window when Z_FINISH is used. 542 543 If a preset dictionary is needed after this call (see inflateSetDictionary 544 below), inflate sets strm->adler to the Adler-32 checksum of the dictionary 545 chosen by the compressor and returns Z_NEED_DICT; otherwise it sets 546 strm->adler to the Adler-32 checksum of all output produced so far (that is, 547 total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described 548 below. At the end of the stream, inflate() checks that its computed adler32 549 checksum is equal to that saved by the compressor and returns Z_STREAM_END 550 only if the checksum is correct. 551 552 inflate() can decompress and check either zlib-wrapped or gzip-wrapped 553 deflate data. The header type is detected automatically, if requested when 554 initializing with inflateInit2(). Any information contained in the gzip 555 header is not retained, so applications that need that information should 556 instead use raw inflate, see inflateInit2() below, or inflateBack() and 557 perform their own processing of the gzip header and trailer. When processing 558 gzip-wrapped deflate data, strm->adler32 is set to the CRC-32 of the output 559 producted so far. The CRC-32 is checked against the gzip trailer. 560 561 inflate() returns Z_OK if some progress has been made (more input processed 562 or more output produced), Z_STREAM_END if the end of the compressed data has 563 been reached and all uncompressed output has been produced, Z_NEED_DICT if a 564 preset dictionary is needed at this point, Z_DATA_ERROR if the input data was 565 corrupted (input stream not conforming to the zlib format or incorrect check 566 value), Z_STREAM_ERROR if the stream structure was inconsistent (for example 567 next_in or next_out was Z_NULL), Z_MEM_ERROR if there was not enough memory, 568 Z_BUF_ERROR if no progress is possible or if there was not enough room in the 569 output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and 570 inflate() can be called again with more input and more output space to 571 continue decompressing. If Z_DATA_ERROR is returned, the application may 572 then call inflateSync() to look for a good compression block if a partial 573 recovery of the data is desired. 574 */ 575 576 577 ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm)); 578 /* 579 All dynamically allocated data structures for this stream are freed. 580 This function discards any unprocessed input and does not flush any pending 581 output. 582 583 inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state 584 was inconsistent. In the error case, msg may be set but then points to a 585 static string (which must not be deallocated). 586 */ 587 588 589 /* Advanced functions */ 590 591 /* 592 The following functions are needed only in some special applications. 593 */ 594 595 /* 596 ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm, 597 int level, 598 int method, 599 int windowBits, 600 int memLevel, 601 int strategy)); 602 603 This is another version of deflateInit with more compression options. The 604 fields next_in, zalloc, zfree and opaque must be initialized before by the 605 caller. 606 607 The method parameter is the compression method. It must be Z_DEFLATED in 608 this version of the library. 609 610 The windowBits parameter is the base two logarithm of the window size 611 (the size of the history buffer). It should be in the range 8..15 for this 612 version of the library. Larger values of this parameter result in better 613 compression at the expense of memory usage. The default value is 15 if 614 deflateInit is used instead. 615 616 windowBits can also be -8..-15 for raw deflate. In this case, -windowBits 617 determines the window size. deflate() will then generate raw deflate data 618 with no zlib header or trailer, and will not compute an adler32 check value. 619 620 windowBits can also be greater than 15 for optional gzip encoding. Add 621 16 to windowBits to write a simple gzip header and trailer around the 622 compressed data instead of a zlib wrapper. The gzip header will have no 623 file name, no extra data, no comment, no modification time (set to zero), no 624 header crc, and the operating system will be set to 255 (unknown). If a 625 gzip stream is being written, strm->adler is a crc32 instead of an adler32. 626 627 The memLevel parameter specifies how much memory should be allocated 628 for the internal compression state. memLevel=1 uses minimum memory but is 629 slow and reduces compression ratio; memLevel=9 uses maximum memory for 630 optimal speed. The default value is 8. See zconf.h for total memory usage 631 as a function of windowBits and memLevel. 632 633 The strategy parameter is used to tune the compression algorithm. Use the 634 value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a 635 filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no 636 string match), or Z_RLE to limit match distances to one (run-length 637 encoding). Filtered data consists mostly of small values with a somewhat 638 random distribution. In this case, the compression algorithm is tuned to 639 compress them better. The effect of Z_FILTERED is to force more Huffman 640 coding and less string matching; it is somewhat intermediate between 641 Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as 642 fast as Z_HUFFMAN_ONLY, but give better compression for PNG image data. The 643 strategy parameter only affects the compression ratio but not the 644 correctness of the compressed output even if it is not set appropriately. 645 Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler 646 decoder for special applications. 647 648 deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 649 memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid 650 method), or Z_VERSION_ERROR if the zlib library version (zlib_version) is 651 incompatible with the version assumed by the caller (ZLIB_VERSION). msg is 652 set to null if there is no error message. deflateInit2 does not perform any 653 compression: this will be done by deflate(). 654 */ 655 656 ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm, 657 const Bytef *dictionary, 658 uInt dictLength)); 659 /* 660 Initializes the compression dictionary from the given byte sequence 661 without producing any compressed output. When using the zlib format, this 662 function must be called immediately after deflateInit, deflateInit2 or 663 deflateReset, and before any call of deflate. When doing raw deflate, this 664 function must be called either before any call of deflate, or immediately 665 after the completion of a deflate block, i.e. after all input has been 666 consumed and all output has been delivered when using any of the flush 667 options Z_BLOCK, Z_PARTIAL_FLUSH, Z_SYNC_FLUSH, or Z_FULL_FLUSH. The 668 compressor and decompressor must use exactly the same dictionary (see 669 inflateSetDictionary). 670 671 The dictionary should consist of strings (byte sequences) that are likely 672 to be encountered later in the data to be compressed, with the most commonly 673 used strings preferably put towards the end of the dictionary. Using a 674 dictionary is most useful when the data to be compressed is short and can be 675 predicted with good accuracy; the data can then be compressed better than 676 with the default empty dictionary. 677 678 Depending on the size of the compression data structures selected by 679 deflateInit or deflateInit2, a part of the dictionary may in effect be 680 discarded, for example if the dictionary is larger than the window size 681 provided in deflateInit or deflateInit2. Thus the strings most likely to be 682 useful should be put at the end of the dictionary, not at the front. In 683 addition, the current implementation of deflate will use at most the window 684 size minus 262 bytes of the provided dictionary. 685 686 Upon return of this function, strm->adler is set to the adler32 value 687 of the dictionary; the decompressor may later use this value to determine 688 which dictionary has been used by the compressor. (The adler32 value 689 applies to the whole dictionary even if only a subset of the dictionary is 690 actually used by the compressor.) If a raw deflate was requested, then the 691 adler32 value is not computed and strm->adler is not set. 692 693 deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a 694 parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is 695 inconsistent (for example if deflate has already been called for this stream 696 or if not at a block boundary for raw deflate). deflateSetDictionary does 697 not perform any compression: this will be done by deflate(). 698 */ 699 700 ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest, 701 z_streamp source)); 702 /* 703 Sets the destination stream as a complete copy of the source stream. 704 705 This function can be useful when several compression strategies will be 706 tried, for example when there are several ways of pre-processing the input 707 data with a filter. The streams that will be discarded should then be freed 708 by calling deflateEnd. Note that deflateCopy duplicates the internal 709 compression state which can be quite large, so this strategy is slow and can 710 consume lots of memory. 711 712 deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not 713 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent 714 (such as zalloc being Z_NULL). msg is left unchanged in both source and 715 destination. 716 */ 717 718 ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm)); 719 /* 720 This function is equivalent to deflateEnd followed by deflateInit, 721 but does not free and reallocate all the internal compression state. The 722 stream will keep the same compression level and any other attributes that 723 may have been set by deflateInit2. 724 725 deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source 726 stream state was inconsistent (such as zalloc or state being Z_NULL). 727 */ 728 729 ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm, 730 int level, 731 int strategy)); 732 /* 733 Dynamically update the compression level and compression strategy. The 734 interpretation of level and strategy is as in deflateInit2. This can be 735 used to switch between compression and straight copy of the input data, or 736 to switch to a different kind of input data requiring a different strategy. 737 If the compression level is changed, the input available so far is 738 compressed with the old level (and may be flushed); the new level will take 739 effect only at the next call of deflate(). 740 741 Before the call of deflateParams, the stream state must be set as for 742 a call of deflate(), since the currently available input may have to be 743 compressed and flushed. In particular, strm->avail_out must be non-zero. 744 745 deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source 746 stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR if 747 strm->avail_out was zero. 748 */ 749 750 ZEXTERN int ZEXPORT deflateTune OF((z_streamp strm, 751 int good_length, 752 int max_lazy, 753 int nice_length, 754 int max_chain)); 755 /* 756 Fine tune deflate's internal compression parameters. This should only be 757 used by someone who understands the algorithm used by zlib's deflate for 758 searching for the best matching string, and even then only by the most 759 fanatic optimizer trying to squeeze out the last compressed bit for their 760 specific input data. Read the deflate.c source code for the meaning of the 761 max_lazy, good_length, nice_length, and max_chain parameters. 762 763 deflateTune() can be called after deflateInit() or deflateInit2(), and 764 returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream. 765 */ 766 767 ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm, 768 uLong sourceLen)); 769 /* 770 deflateBound() returns an upper bound on the compressed size after 771 deflation of sourceLen bytes. It must be called after deflateInit() or 772 deflateInit2(), and after deflateSetHeader(), if used. This would be used 773 to allocate an output buffer for deflation in a single pass, and so would be 774 called before deflate(). If that first deflate() call is provided the 775 sourceLen input bytes, an output buffer allocated to the size returned by 776 deflateBound(), and the flush value Z_FINISH, then deflate() is guaranteed 777 to return Z_STREAM_END. Note that it is possible for the compressed size to 778 be larger than the value returned by deflateBound() if flush options other 779 than Z_FINISH or Z_NO_FLUSH are used. 780 */ 781 782 ZEXTERN int ZEXPORT deflatePending OF((z_streamp strm, 783 unsigned *pending, 784 int *bits)); 785 /* 786 deflatePending() returns the number of bytes and bits of output that have 787 been generated, but not yet provided in the available output. The bytes not 788 provided would be due to the available output space having being consumed. 789 The number of bits of output not provided are between 0 and 7, where they 790 await more bits to join them in order to fill out a full byte. If pending 791 or bits are Z_NULL, then those values are not set. 792 793 deflatePending returns Z_OK if success, or Z_STREAM_ERROR if the source 794 stream state was inconsistent. 795 */ 796 797 ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm, 798 int bits, 799 int value)); 800 /* 801 deflatePrime() inserts bits in the deflate output stream. The intent 802 is that this function is used to start off the deflate output with the bits 803 leftover from a previous deflate stream when appending to it. As such, this 804 function can only be used for raw deflate, and must be used before the first 805 deflate() call after a deflateInit2() or deflateReset(). bits must be less 806 than or equal to 16, and that many of the least significant bits of value 807 will be inserted in the output. 808 809 deflatePrime returns Z_OK if success, Z_BUF_ERROR if there was not enough 810 room in the internal buffer to insert the bits, or Z_STREAM_ERROR if the 811 source stream state was inconsistent. 812 */ 813 814 ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm, 815 gz_headerp head)); 816 /* 817 deflateSetHeader() provides gzip header information for when a gzip 818 stream is requested by deflateInit2(). deflateSetHeader() may be called 819 after deflateInit2() or deflateReset() and before the first call of 820 deflate(). The text, time, os, extra field, name, and comment information 821 in the provided gz_header structure are written to the gzip header (xflag is 822 ignored -- the extra flags are set according to the compression level). The 823 caller must assure that, if not Z_NULL, name and comment are terminated with 824 a zero byte, and that if extra is not Z_NULL, that extra_len bytes are 825 available there. If hcrc is true, a gzip header crc is included. Note that 826 the current versions of the command-line version of gzip (up through version 827 1.3.x) do not support header crc's, and will report that it is a "multi-part 828 gzip file" and give up. 829 830 If deflateSetHeader is not used, the default gzip header has text false, 831 the time set to zero, and os set to 255, with no extra, name, or comment 832 fields. The gzip header is returned to the default state by deflateReset(). 833 834 deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source 835 stream state was inconsistent. 836 */ 837 838 /* 839 ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm, 840 int windowBits)); 841 842 This is another version of inflateInit with an extra parameter. The 843 fields next_in, avail_in, zalloc, zfree and opaque must be initialized 844 before by the caller. 845 846 The windowBits parameter is the base two logarithm of the maximum window 847 size (the size of the history buffer). It should be in the range 8..15 for 848 this version of the library. The default value is 15 if inflateInit is used 849 instead. windowBits must be greater than or equal to the windowBits value 850 provided to deflateInit2() while compressing, or it must be equal to 15 if 851 deflateInit2() was not used. If a compressed stream with a larger window 852 size is given as input, inflate() will return with the error code 853 Z_DATA_ERROR instead of trying to allocate a larger window. 854 855 windowBits can also be zero to request that inflate use the window size in 856 the zlib header of the compressed stream. 857 858 windowBits can also be -8..-15 for raw inflate. In this case, -windowBits 859 determines the window size. inflate() will then process raw deflate data, 860 not looking for a zlib or gzip header, not generating a check value, and not 861 looking for any check values for comparison at the end of the stream. This 862 is for use with other formats that use the deflate compressed data format 863 such as zip. Those formats provide their own check values. If a custom 864 format is developed using the raw deflate format for compressed data, it is 865 recommended that a check value such as an adler32 or a crc32 be applied to 866 the uncompressed data as is done in the zlib, gzip, and zip formats. For 867 most applications, the zlib format should be used as is. Note that comments 868 above on the use in deflateInit2() applies to the magnitude of windowBits. 869 870 windowBits can also be greater than 15 for optional gzip decoding. Add 871 32 to windowBits to enable zlib and gzip decoding with automatic header 872 detection, or add 16 to decode only the gzip format (the zlib format will 873 return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is a 874 crc32 instead of an adler32. 875 876 inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 877 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the 878 version assumed by the caller, or Z_STREAM_ERROR if the parameters are 879 invalid, such as a null pointer to the structure. msg is set to null if 880 there is no error message. inflateInit2 does not perform any decompression 881 apart from possibly reading the zlib header if present: actual decompression 882 will be done by inflate(). (So next_in and avail_in may be modified, but 883 next_out and avail_out are unused and unchanged.) The current implementation 884 of inflateInit2() does not process any header information -- that is 885 deferred until inflate() is called. 886 */ 887 888 ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm, 889 const Bytef *dictionary, 890 uInt dictLength)); 891 /* 892 Initializes the decompression dictionary from the given uncompressed byte 893 sequence. This function must be called immediately after a call of inflate, 894 if that call returned Z_NEED_DICT. The dictionary chosen by the compressor 895 can be determined from the adler32 value returned by that call of inflate. 896 The compressor and decompressor must use exactly the same dictionary (see 897 deflateSetDictionary). For raw inflate, this function can be called at any 898 time to set the dictionary. If the provided dictionary is smaller than the 899 window and there is already data in the window, then the provided dictionary 900 will amend what's there. The application must insure that the dictionary 901 that was used for compression is provided. 902 903 inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a 904 parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is 905 inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the 906 expected one (incorrect adler32 value). inflateSetDictionary does not 907 perform any decompression: this will be done by subsequent calls of 908 inflate(). 909 */ 910 911 ZEXTERN int ZEXPORT inflateGetDictionary OF((z_streamp strm, 912 Bytef *dictionary, 913 uInt *dictLength)); 914 /* 915 Returns the sliding dictionary being maintained by inflate. dictLength is 916 set to the number of bytes in the dictionary, and that many bytes are copied 917 to dictionary. dictionary must have enough space, where 32768 bytes is 918 always enough. If inflateGetDictionary() is called with dictionary equal to 919 Z_NULL, then only the dictionary length is returned, and nothing is copied. 920 Similary, if dictLength is Z_NULL, then it is not set. 921 922 inflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the 923 stream state is inconsistent. 924 */ 925 926 ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm)); 927 /* 928 Skips invalid compressed data until a possible full flush point (see above 929 for the description of deflate with Z_FULL_FLUSH) can be found, or until all 930 available input is skipped. No output is provided. 931 932 inflateSync searches for a 00 00 FF FF pattern in the compressed data. 933 All full flush points have this pattern, but not all occurrences of this 934 pattern are full flush points. 935 936 inflateSync returns Z_OK if a possible full flush point has been found, 937 Z_BUF_ERROR if no more input was provided, Z_DATA_ERROR if no flush point 938 has been found, or Z_STREAM_ERROR if the stream structure was inconsistent. 939 In the success case, the application may save the current current value of 940 total_in which indicates where valid compressed data was found. In the 941 error case, the application may repeatedly call inflateSync, providing more 942 input each time, until success or end of the input data. 943 */ 944 945 ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest, 946 z_streamp source)); 947 /* 948 Sets the destination stream as a complete copy of the source stream. 949 950 This function can be useful when randomly accessing a large stream. The 951 first pass through the stream can periodically record the inflate state, 952 allowing restarting inflate at those points when randomly accessing the 953 stream. 954 955 inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not 956 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent 957 (such as zalloc being Z_NULL). msg is left unchanged in both source and 958 destination. 959 */ 960 961 ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm)); 962 /* 963 This function is equivalent to inflateEnd followed by inflateInit, 964 but does not free and reallocate all the internal decompression state. The 965 stream will keep attributes that may have been set by inflateInit2. 966 967 inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source 968 stream state was inconsistent (such as zalloc or state being Z_NULL). 969 */ 970 971 ZEXTERN int ZEXPORT inflateReset2 OF((z_streamp strm, 972 int windowBits)); 973 /* 974 This function is the same as inflateReset, but it also permits changing 975 the wrap and window size requests. The windowBits parameter is interpreted 976 the same as it is for inflateInit2. 977 978 inflateReset2 returns Z_OK if success, or Z_STREAM_ERROR if the source 979 stream state was inconsistent (such as zalloc or state being Z_NULL), or if 980 the windowBits parameter is invalid. 981 */ 982 983 ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm, 984 int bits, 985 int value)); 986 /* 987 This function inserts bits in the inflate input stream. The intent is 988 that this function is used to start inflating at a bit position in the 989 middle of a byte. The provided bits will be used before any bytes are used 990 from next_in. This function should only be used with raw inflate, and 991 should be used before the first inflate() call after inflateInit2() or 992 inflateReset(). bits must be less than or equal to 16, and that many of the 993 least significant bits of value will be inserted in the input. 994 995 If bits is negative, then the input stream bit buffer is emptied. Then 996 inflatePrime() can be called again to put bits in the buffer. This is used 997 to clear out bits leftover after feeding inflate a block description prior 998 to feeding inflate codes. 999 1000 inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source 1001 stream state was inconsistent. 1002 */ 1003 1004 ZEXTERN long ZEXPORT inflateMark OF((z_streamp strm)); 1005 /* 1006 This function returns two values, one in the lower 16 bits of the return 1007 value, and the other in the remaining upper bits, obtained by shifting the 1008 return value down 16 bits. If the upper value is -1 and the lower value is 1009 zero, then inflate() is currently decoding information outside of a block. 1010 If the upper value is -1 and the lower value is non-zero, then inflate is in 1011 the middle of a stored block, with the lower value equaling the number of 1012 bytes from the input remaining to copy. If the upper value is not -1, then 1013 it is the number of bits back from the current bit position in the input of 1014 the code (literal or length/distance pair) currently being processed. In 1015 that case the lower value is the number of bytes already emitted for that 1016 code. 1017 1018 A code is being processed if inflate is waiting for more input to complete 1019 decoding of the code, or if it has completed decoding but is waiting for 1020 more output space to write the literal or match data. 1021 1022 inflateMark() is used to mark locations in the input data for random 1023 access, which may be at bit positions, and to note those cases where the 1024 output of a code may span boundaries of random access blocks. The current 1025 location in the input stream can be determined from avail_in and data_type 1026 as noted in the description for the Z_BLOCK flush parameter for inflate. 1027 1028 inflateMark returns the value noted above or -1 << 16 if the provided 1029 source stream state was inconsistent. 1030 */ 1031 1032 ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm, 1033 gz_headerp head)); 1034 /* 1035 inflateGetHeader() requests that gzip header information be stored in the 1036 provided gz_header structure. inflateGetHeader() may be called after 1037 inflateInit2() or inflateReset(), and before the first call of inflate(). 1038 As inflate() processes the gzip stream, head->done is zero until the header 1039 is completed, at which time head->done is set to one. If a zlib stream is 1040 being decoded, then head->done is set to -1 to indicate that there will be 1041 no gzip header information forthcoming. Note that Z_BLOCK or Z_TREES can be 1042 used to force inflate() to return immediately after header processing is 1043 complete and before any actual data is decompressed. 1044 1045 The text, time, xflags, and os fields are filled in with the gzip header 1046 contents. hcrc is set to true if there is a header CRC. (The header CRC 1047 was valid if done is set to one.) If extra is not Z_NULL, then extra_max 1048 contains the maximum number of bytes to write to extra. Once done is true, 1049 extra_len contains the actual extra field length, and extra contains the 1050 extra field, or that field truncated if extra_max is less than extra_len. 1051 If name is not Z_NULL, then up to name_max characters are written there, 1052 terminated with a zero unless the length is greater than name_max. If 1053 comment is not Z_NULL, then up to comm_max characters are written there, 1054 terminated with a zero unless the length is greater than comm_max. When any 1055 of extra, name, or comment are not Z_NULL and the respective field is not 1056 present in the header, then that field is set to Z_NULL to signal its 1057 absence. This allows the use of deflateSetHeader() with the returned 1058 structure to duplicate the header. However if those fields are set to 1059 allocated memory, then the application will need to save those pointers 1060 elsewhere so that they can be eventually freed. 1061 1062 If inflateGetHeader is not used, then the header information is simply 1063 discarded. The header is always checked for validity, including the header 1064 CRC if present. inflateReset() will reset the process to discard the header 1065 information. The application would need to call inflateGetHeader() again to 1066 retrieve the header from the next gzip stream. 1067 1068 inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source 1069 stream state was inconsistent. 1070 */ 1071 1072 /* 1073 ZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits, 1074 unsigned char FAR *window)); 1075 1076 Initialize the internal stream state for decompression using inflateBack() 1077 calls. The fields zalloc, zfree and opaque in strm must be initialized 1078 before the call. If zalloc and zfree are Z_NULL, then the default library- 1079 derived memory allocation routines are used. windowBits is the base two 1080 logarithm of the window size, in the range 8..15. window is a caller 1081 supplied buffer of that size. Except for special applications where it is 1082 assured that deflate was used with small window sizes, windowBits must be 15 1083 and a 32K byte window must be supplied to be able to decompress general 1084 deflate streams. 1085 1086 See inflateBack() for the usage of these routines. 1087 1088 inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of 1089 the parameters are invalid, Z_MEM_ERROR if the internal state could not be 1090 allocated, or Z_VERSION_ERROR if the version of the library does not match 1091 the version of the header file. 1092 */ 1093 1094 typedef unsigned (*in_func) OF((void FAR *, 1095 z_const unsigned char FAR * FAR *)); 1096 typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned)); 1097 1098 ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm, 1099 in_func in, void FAR *in_desc, 1100 out_func out, void FAR *out_desc)); 1101 /* 1102 inflateBack() does a raw inflate with a single call using a call-back 1103 interface for input and output. This is potentially more efficient than 1104 inflate() for file i/o applications, in that it avoids copying between the 1105 output and the sliding window by simply making the window itself the output 1106 buffer. inflate() can be faster on modern CPUs when used with large 1107 buffers. inflateBack() trusts the application to not change the output 1108 buffer passed by the output function, at least until inflateBack() returns. 1109 1110 inflateBackInit() must be called first to allocate the internal state 1111 and to initialize the state with the user-provided window buffer. 1112 inflateBack() may then be used multiple times to inflate a complete, raw 1113 deflate stream with each call. inflateBackEnd() is then called to free the 1114 allocated state. 1115 1116 A raw deflate stream is one with no zlib or gzip header or trailer. 1117 This routine would normally be used in a utility that reads zip or gzip 1118 files and writes out uncompressed files. The utility would decode the 1119 header and process the trailer on its own, hence this routine expects only 1120 the raw deflate stream to decompress. This is different from the normal 1121 behavior of inflate(), which expects either a zlib or gzip header and 1122 trailer around the deflate stream. 1123 1124 inflateBack() uses two subroutines supplied by the caller that are then 1125 called by inflateBack() for input and output. inflateBack() calls those 1126 routines until it reads a complete deflate stream and writes out all of the 1127 uncompressed data, or until it encounters an error. The function's 1128 parameters and return types are defined above in the in_func and out_func 1129 typedefs. inflateBack() will call in(in_desc, &buf) which should return the 1130 number of bytes of provided input, and a pointer to that input in buf. If 1131 there is no input available, in() must return zero--buf is ignored in that 1132 case--and inflateBack() will return a buffer error. inflateBack() will call 1133 out(out_desc, buf, len) to write the uncompressed data buf[0..len-1]. out() 1134 should return zero on success, or non-zero on failure. If out() returns 1135 non-zero, inflateBack() will return with an error. Neither in() nor out() 1136 are permitted to change the contents of the window provided to 1137 inflateBackInit(), which is also the buffer that out() uses to write from. 1138 The length written by out() will be at most the window size. Any non-zero 1139 amount of input may be provided by in(). 1140 1141 For convenience, inflateBack() can be provided input on the first call by 1142 setting strm->next_in and strm->avail_in. If that input is exhausted, then 1143 in() will be called. Therefore strm->next_in must be initialized before 1144 calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called 1145 immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in 1146 must also be initialized, and then if strm->avail_in is not zero, input will 1147 initially be taken from strm->next_in[0 .. strm->avail_in - 1]. 1148 1149 The in_desc and out_desc parameters of inflateBack() is passed as the 1150 first parameter of in() and out() respectively when they are called. These 1151 descriptors can be optionally used to pass any information that the caller- 1152 supplied in() and out() functions need to do their job. 1153 1154 On return, inflateBack() will set strm->next_in and strm->avail_in to 1155 pass back any unused input that was provided by the last in() call. The 1156 return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR 1157 if in() or out() returned an error, Z_DATA_ERROR if there was a format error 1158 in the deflate stream (in which case strm->msg is set to indicate the nature 1159 of the error), or Z_STREAM_ERROR if the stream was not properly initialized. 1160 In the case of Z_BUF_ERROR, an input or output error can be distinguished 1161 using strm->next_in which will be Z_NULL only if in() returned an error. If 1162 strm->next_in is not Z_NULL, then the Z_BUF_ERROR was due to out() returning 1163 non-zero. (in() will always be called before out(), so strm->next_in is 1164 assured to be defined if out() returns non-zero.) Note that inflateBack() 1165 cannot return Z_OK. 1166 */ 1167 1168 ZEXTERN int ZEXPORT inflateBackEnd OF((z_streamp strm)); 1169 /* 1170 All memory allocated by inflateBackInit() is freed. 1171 1172 inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream 1173 state was inconsistent. 1174 */ 1175 1176 ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void)); 1177 /* Return flags indicating compile-time options. 1178 1179 Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other: 1180 1.0: size of uInt 1181 3.2: size of uLong 1182 5.4: size of voidpf (pointer) 1183 7.6: size of z_off_t 1184 1185 Compiler, assembler, and debug options: 1186 8: DEBUG 1187 9: ASMV or ASMINF -- use ASM code 1188 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention 1189 11: 0 (reserved) 1190 1191 One-time table building (smaller code, but not thread-safe if true): 1192 12: BUILDFIXED -- build static block decoding tables when needed 1193 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed 1194 14,15: 0 (reserved) 1195 1196 Library content (indicates missing functionality): 1197 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking 1198 deflate code when not needed) 1199 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect 1200 and decode gzip streams (to avoid linking crc code) 1201 18-19: 0 (reserved) 1202 1203 Operation variations (changes in library functionality): 1204 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate 1205 21: FASTEST -- deflate algorithm with only one, lowest compression level 1206 22,23: 0 (reserved) 1207 1208 The sprintf variant used by gzprintf (zero is best): 1209 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format 1210 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure! 1211 26: 0 = returns value, 1 = void -- 1 means inferred string length returned 1212 1213 Remainder: 1214 27-31: 0 (reserved) 1215 */ 1216 1217 #ifndef Z_SOLO 1218 1219 /* utility functions */ 1220 1221 /* 1222 The following utility functions are implemented on top of the basic 1223 stream-oriented functions. To simplify the interface, some default options 1224 are assumed (compression level and memory usage, standard memory allocation 1225 functions). The source code of these utility functions can be modified if 1226 you need special options. 1227 */ 1228 1229 ZEXTERN int ZEXPORT compress OF((Bytef *dest, uLongf *destLen, 1230 const Bytef *source, uLong sourceLen)); 1231 /* 1232 Compresses the source buffer into the destination buffer. sourceLen is 1233 the byte length of the source buffer. Upon entry, destLen is the total size 1234 of the destination buffer, which must be at least the value returned by 1235 compressBound(sourceLen). Upon exit, destLen is the actual size of the 1236 compressed buffer. 1237 1238 compress returns Z_OK if success, Z_MEM_ERROR if there was not 1239 enough memory, Z_BUF_ERROR if there was not enough room in the output 1240 buffer. 1241 */ 1242 1243 ZEXTERN int ZEXPORT compress2 OF((Bytef *dest, uLongf *destLen, 1244 const Bytef *source, uLong sourceLen, 1245 int level)); 1246 /* 1247 Compresses the source buffer into the destination buffer. The level 1248 parameter has the same meaning as in deflateInit. sourceLen is the byte 1249 length of the source buffer. Upon entry, destLen is the total size of the 1250 destination buffer, which must be at least the value returned by 1251 compressBound(sourceLen). Upon exit, destLen is the actual size of the 1252 compressed buffer. 1253 1254 compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 1255 memory, Z_BUF_ERROR if there was not enough room in the output buffer, 1256 Z_STREAM_ERROR if the level parameter is invalid. 1257 */ 1258 1259 ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen)); 1260 /* 1261 compressBound() returns an upper bound on the compressed size after 1262 compress() or compress2() on sourceLen bytes. It would be used before a 1263 compress() or compress2() call to allocate the destination buffer. 1264 */ 1265 1266 ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen, 1267 const Bytef *source, uLong sourceLen)); 1268 /* 1269 Decompresses the source buffer into the destination buffer. sourceLen is 1270 the byte length of the source buffer. Upon entry, destLen is the total size 1271 of the destination buffer, which must be large enough to hold the entire 1272 uncompressed data. (The size of the uncompressed data must have been saved 1273 previously by the compressor and transmitted to the decompressor by some 1274 mechanism outside the scope of this compression library.) Upon exit, destLen 1275 is the actual size of the uncompressed buffer. 1276 1277 uncompress returns Z_OK if success, Z_MEM_ERROR if there was not 1278 enough memory, Z_BUF_ERROR if there was not enough room in the output 1279 buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete. In 1280 the case where there is not enough room, uncompress() will fill the output 1281 buffer with the uncompressed data up to that point. 1282 */ 1283 1284 /* gzip file access functions */ 1285 1286 /* 1287 This library supports reading and writing files in gzip (.gz) format with 1288 an interface similar to that of stdio, using the functions that start with 1289 "gz". The gzip format is different from the zlib format. gzip is a gzip 1290 wrapper, documented in RFC 1952, wrapped around a deflate stream. 1291 */ 1292 1293 typedef struct gzFile_s *gzFile; /* semi-opaque gzip file descriptor */ 1294 1295 /* 1296 ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode)); 1297 1298 Opens a gzip (.gz) file for reading or writing. The mode parameter is as 1299 in fopen ("rb" or "wb") but can also include a compression level ("wb9") or 1300 a strategy: 'f' for filtered data as in "wb6f", 'h' for Huffman-only 1301 compression as in "wb1h", 'R' for run-length encoding as in "wb1R", or 'F' 1302 for fixed code compression as in "wb9F". (See the description of 1303 deflateInit2 for more information about the strategy parameter.) 'T' will 1304 request transparent writing or appending with no compression and not using 1305 the gzip format. 1306 1307 "a" can be used instead of "w" to request that the gzip stream that will 1308 be written be appended to the file. "+" will result in an error, since 1309 reading and writing to the same gzip file is not supported. The addition of 1310 "x" when writing will create the file exclusively, which fails if the file 1311 already exists. On systems that support it, the addition of "e" when 1312 reading or writing will set the flag to close the file on an execve() call. 1313 1314 These functions, as well as gzip, will read and decode a sequence of gzip 1315 streams in a file. The append function of gzopen() can be used to create 1316 such a file. (Also see gzflush() for another way to do this.) When 1317 appending, gzopen does not test whether the file begins with a gzip stream, 1318 nor does it look for the end of the gzip streams to begin appending. gzopen 1319 will simply append a gzip stream to the existing file. 1320 1321 gzopen can be used to read a file which is not in gzip format; in this 1322 case gzread will directly read from the file without decompression. When 1323 reading, this will be detected automatically by looking for the magic two- 1324 byte gzip header. 1325 1326 gzopen returns NULL if the file could not be opened, if there was 1327 insufficient memory to allocate the gzFile state, or if an invalid mode was 1328 specified (an 'r', 'w', or 'a' was not provided, or '+' was provided). 1329 errno can be checked to determine if the reason gzopen failed was that the 1330 file could not be opened. 1331 */ 1332 1333 ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode)); 1334 /* 1335 gzdopen associates a gzFile with the file descriptor fd. File descriptors 1336 are obtained from calls like open, dup, creat, pipe or fileno (if the file 1337 has been previously opened with fopen). The mode parameter is as in gzopen. 1338 1339 The next call of gzclose on the returned gzFile will also close the file 1340 descriptor fd, just like fclose(fdopen(fd, mode)) closes the file descriptor 1341 fd. If you want to keep fd open, use fd = dup(fd_keep); gz = gzdopen(fd, 1342 mode);. The duplicated descriptor should be saved to avoid a leak, since 1343 gzdopen does not close fd if it fails. If you are using fileno() to get the 1344 file descriptor from a FILE *, then you will have to use dup() to avoid 1345 double-close()ing the file descriptor. Both gzclose() and fclose() will 1346 close the associated file descriptor, so they need to have different file 1347 descriptors. 1348 1349 gzdopen returns NULL if there was insufficient memory to allocate the 1350 gzFile state, if an invalid mode was specified (an 'r', 'w', or 'a' was not 1351 provided, or '+' was provided), or if fd is -1. The file descriptor is not 1352 used until the next gz* read, write, seek, or close operation, so gzdopen 1353 will not detect if fd is invalid (unless fd is -1). 1354 */ 1355 1356 ZEXTERN int ZEXPORT gzbuffer OF((gzFile file, unsigned size)); 1357 /* 1358 Set the internal buffer size used by this library's functions. The 1359 default buffer size is 8192 bytes. This function must be called after 1360 gzopen() or gzdopen(), and before any other calls that read or write the 1361 file. The buffer memory allocation is always deferred to the first read or 1362 write. Two buffers are allocated, either both of the specified size when 1363 writing, or one of the specified size and the other twice that size when 1364 reading. A larger buffer size of, for example, 64K or 128K bytes will 1365 noticeably increase the speed of decompression (reading). 1366 1367 The new buffer size also affects the maximum length for gzprintf(). 1368 1369 gzbuffer() returns 0 on success, or -1 on failure, such as being called 1370 too late. 1371 */ 1372 1373 ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy)); 1374 /* 1375 Dynamically update the compression level or strategy. See the description 1376 of deflateInit2 for the meaning of these parameters. 1377 1378 gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not 1379 opened for writing. 1380 */ 1381 1382 ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len)); 1383 /* 1384 Reads the given number of uncompressed bytes from the compressed file. If 1385 the input file is not in gzip format, gzread copies the given number of 1386 bytes into the buffer directly from the file. 1387 1388 After reaching the end of a gzip stream in the input, gzread will continue 1389 to read, looking for another gzip stream. Any number of gzip streams may be 1390 concatenated in the input file, and will all be decompressed by gzread(). 1391 If something other than a gzip stream is encountered after a gzip stream, 1392 that remaining trailing garbage is ignored (and no error is returned). 1393 1394 gzread can be used to read a gzip file that is being concurrently written. 1395 Upon reaching the end of the input, gzread will return with the available 1396 data. If the error code returned by gzerror is Z_OK or Z_BUF_ERROR, then 1397 gzclearerr can be used to clear the end of file indicator in order to permit 1398 gzread to be tried again. Z_OK indicates that a gzip stream was completed 1399 on the last gzread. Z_BUF_ERROR indicates that the input file ended in the 1400 middle of a gzip stream. Note that gzread does not return -1 in the event 1401 of an incomplete gzip stream. This error is deferred until gzclose(), which 1402 will return Z_BUF_ERROR if the last gzread ended in the middle of a gzip 1403 stream. Alternatively, gzerror can be used before gzclose to detect this 1404 case. 1405 1406 gzread returns the number of uncompressed bytes actually read, less than 1407 len for end of file, or -1 for error. 1408 */ 1409 1410 ZEXTERN int ZEXPORT gzwrite OF((gzFile file, 1411 voidpc buf, unsigned len)); 1412 /* 1413 Writes the given number of uncompressed bytes into the compressed file. 1414 gzwrite returns the number of uncompressed bytes written or 0 in case of 1415 error. 1416 */ 1417 1418 ZEXTERN int ZEXPORTVA gzprintf Z_ARG((gzFile file, const char *format, ...)); 1419 /* 1420 Converts, formats, and writes the arguments to the compressed file under 1421 control of the format string, as in fprintf. gzprintf returns the number of 1422 uncompressed bytes actually written, or 0 in case of error. The number of 1423 uncompressed bytes written is limited to 8191, or one less than the buffer 1424 size given to gzbuffer(). The caller should assure that this limit is not 1425 exceeded. If it is exceeded, then gzprintf() will return an error (0) with 1426 nothing written. In this case, there may also be a buffer overflow with 1427 unpredictable consequences, which is possible only if zlib was compiled with 1428 the insecure functions sprintf() or vsprintf() because the secure snprintf() 1429 or vsnprintf() functions were not available. This can be determined using 1430 zlibCompileFlags(). 1431 */ 1432 1433 ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s)); 1434 /* 1435 Writes the given null-terminated string to the compressed file, excluding 1436 the terminating null character. 1437 1438 gzputs returns the number of characters written, or -1 in case of error. 1439 */ 1440 1441 ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len)); 1442 /* 1443 Reads bytes from the compressed file until len-1 characters are read, or a 1444 newline character is read and transferred to buf, or an end-of-file 1445 condition is encountered. If any characters are read or if len == 1, the 1446 string is terminated with a null character. If no characters are read due 1447 to an end-of-file or len < 1, then the buffer is left untouched. 1448 1449 gzgets returns buf which is a null-terminated string, or it returns NULL 1450 for end-of-file or in case of error. If there was an error, the contents at 1451 buf are indeterminate. 1452 */ 1453 1454 ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c)); 1455 /* 1456 Writes c, converted to an unsigned char, into the compressed file. gzputc 1457 returns the value that was written, or -1 in case of error. 1458 */ 1459 1460 ZEXTERN int ZEXPORT gzgetc OF((gzFile file)); 1461 /* 1462 Reads one byte from the compressed file. gzgetc returns this byte or -1 1463 in case of end of file or error. This is implemented as a macro for speed. 1464 As such, it does not do all of the checking the other functions do. I.e. 1465 it does not check to see if file is NULL, nor whether the structure file 1466 points to has been clobbered or not. 1467 */ 1468 1469 ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file)); 1470 /* 1471 Push one character back onto the stream to be read as the first character 1472 on the next read. At least one character of push-back is allowed. 1473 gzungetc() returns the character pushed, or -1 on failure. gzungetc() will 1474 fail if c is -1, and may fail if a character has been pushed but not read 1475 yet. If gzungetc is used immediately after gzopen or gzdopen, at least the 1476 output buffer size of pushed characters is allowed. (See gzbuffer above.) 1477 The pushed character will be discarded if the stream is repositioned with 1478 gzseek() or gzrewind(). 1479 */ 1480 1481 ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush)); 1482 /* 1483 Flushes all pending output into the compressed file. The parameter flush 1484 is as in the deflate() function. The return value is the zlib error number 1485 (see function gzerror below). gzflush is only permitted when writing. 1486 1487 If the flush parameter is Z_FINISH, the remaining data is written and the 1488 gzip stream is completed in the output. If gzwrite() is called again, a new 1489 gzip stream will be started in the output. gzread() is able to read such 1490 concatented gzip streams. 1491 1492 gzflush should be called only when strictly necessary because it will 1493 degrade compression if called too often. 1494 */ 1495 1496 /* 1497 ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file, 1498 z_off_t offset, int whence)); 1499 1500 Sets the starting position for the next gzread or gzwrite on the given 1501 compressed file. The offset represents a number of bytes in the 1502 uncompressed data stream. The whence parameter is defined as in lseek(2); 1503 the value SEEK_END is not supported. 1504 1505 If the file is opened for reading, this function is emulated but can be 1506 extremely slow. If the file is opened for writing, only forward seeks are 1507 supported; gzseek then compresses a sequence of zeroes up to the new 1508 starting position. 1509 1510 gzseek returns the resulting offset location as measured in bytes from 1511 the beginning of the uncompressed stream, or -1 in case of error, in 1512 particular if the file is opened for writing and the new starting position 1513 would be before the current position. 1514 */ 1515 1516 ZEXTERN int ZEXPORT gzrewind OF((gzFile file)); 1517 /* 1518 Rewinds the given file. This function is supported only for reading. 1519 1520 gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET) 1521 */ 1522 1523 /* 1524 ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file)); 1525 1526 Returns the starting position for the next gzread or gzwrite on the given 1527 compressed file. This position represents a number of bytes in the 1528 uncompressed data stream, and is zero when starting, even if appending or 1529 reading a gzip stream from the middle of a file using gzdopen(). 1530 1531 gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR) 1532 */ 1533 1534 /* 1535 ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile file)); 1536 1537 Returns the current offset in the file being read or written. This offset 1538 includes the count of bytes that precede the gzip stream, for example when 1539 appending or when using gzdopen() for reading. When reading, the offset 1540 does not include as yet unused buffered input. This information can be used 1541 for a progress indicator. On error, gzoffset() returns -1. 1542 */ 1543 1544 ZEXTERN int ZEXPORT gzeof OF((gzFile file)); 1545 /* 1546 Returns true (1) if the end-of-file indicator has been set while reading, 1547 false (0) otherwise. Note that the end-of-file indicator is set only if the 1548 read tried to go past the end of the input, but came up short. Therefore, 1549 just like feof(), gzeof() may return false even if there is no more data to 1550 read, in the event that the last read request was for the exact number of 1551 bytes remaining in the input file. This will happen if the input file size 1552 is an exact multiple of the buffer size. 1553 1554 If gzeof() returns true, then the read functions will return no more data, 1555 unless the end-of-file indicator is reset by gzclearerr() and the input file 1556 has grown since the previous end of file was detected. 1557 */ 1558 1559 ZEXTERN int ZEXPORT gzdirect OF((gzFile file)); 1560 /* 1561 Returns true (1) if file is being copied directly while reading, or false 1562 (0) if file is a gzip stream being decompressed. 1563 1564 If the input file is empty, gzdirect() will return true, since the input 1565 does not contain a gzip stream. 1566 1567 If gzdirect() is used immediately after gzopen() or gzdopen() it will 1568 cause buffers to be allocated to allow reading the file to determine if it 1569 is a gzip file. Therefore if gzbuffer() is used, it should be called before 1570 gzdirect(). 1571 1572 When writing, gzdirect() returns true (1) if transparent writing was 1573 requested ("wT" for the gzopen() mode), or false (0) otherwise. (Note: 1574 gzdirect() is not needed when writing. Transparent writing must be 1575 explicitly requested, so the application already knows the answer. When 1576 linking statically, using gzdirect() will include all of the zlib code for 1577 gzip file reading and decompression, which may not be desired.) 1578 */ 1579 1580 ZEXTERN int ZEXPORT gzclose OF((gzFile file)); 1581 /* 1582 Flushes all pending output if necessary, closes the compressed file and 1583 deallocates the (de)compression state. Note that once file is closed, you 1584 cannot call gzerror with file, since its structures have been deallocated. 1585 gzclose must not be called more than once on the same file, just as free 1586 must not be called more than once on the same allocation. 1587 1588 gzclose will return Z_STREAM_ERROR if file is not valid, Z_ERRNO on a 1589 file operation error, Z_MEM_ERROR if out of memory, Z_BUF_ERROR if the 1590 last read ended in the middle of a gzip stream, or Z_OK on success. 1591 */ 1592 1593 ZEXTERN int ZEXPORT gzclose_r OF((gzFile file)); 1594 ZEXTERN int ZEXPORT gzclose_w OF((gzFile file)); 1595 /* 1596 Same as gzclose(), but gzclose_r() is only for use when reading, and 1597 gzclose_w() is only for use when writing or appending. The advantage to 1598 using these instead of gzclose() is that they avoid linking in zlib 1599 compression or decompression code that is not used when only reading or only 1600 writing respectively. If gzclose() is used, then both compression and 1601 decompression code will be included the application when linking to a static 1602 zlib library. 1603 */ 1604 1605 ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum)); 1606 /* 1607 Returns the error message for the last error which occurred on the given 1608 compressed file. errnum is set to zlib error number. If an error occurred 1609 in the file system and not in the compression library, errnum is set to 1610 Z_ERRNO and the application may consult errno to get the exact error code. 1611 1612 The application must not modify the returned string. Future calls to 1613 this function may invalidate the previously returned string. If file is 1614 closed, then the string previously returned by gzerror will no longer be 1615 available. 1616 1617 gzerror() should be used to distinguish errors from end-of-file for those 1618 functions above that do not distinguish those cases in their return values. 1619 */ 1620 1621 ZEXTERN void ZEXPORT gzclearerr OF((gzFile file)); 1622 /* 1623 Clears the error and end-of-file flags for file. This is analogous to the 1624 clearerr() function in stdio. This is useful for continuing to read a gzip 1625 file that is being written concurrently. 1626 */ 1627 1628 #endif /* !Z_SOLO */ 1629 1630 /* checksum functions */ 1631 1632 /* 1633 These functions are not related to compression but are exported 1634 anyway because they might be useful in applications using the compression 1635 library. 1636 */ 1637 1638 ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len)); 1639 /* 1640 Update a running Adler-32 checksum with the bytes buf[0..len-1] and 1641 return the updated checksum. If buf is Z_NULL, this function returns the 1642 required initial value for the checksum. 1643 1644 An Adler-32 checksum is almost as reliable as a CRC32 but can be computed 1645 much faster. 1646 1647 Usage example: 1648 1649 uLong adler = adler32(0L, Z_NULL, 0); 1650 1651 while (read_buffer(buffer, length) != EOF) { 1652 adler = adler32(adler, buffer, length); 1653 } 1654 if (adler != original_adler) error(); 1655 */ 1656 1657 /* 1658 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong adler1, uLong adler2, 1659 z_off_t len2)); 1660 1661 Combine two Adler-32 checksums into one. For two sequences of bytes, seq1 1662 and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for 1663 each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of 1664 seq1 and seq2 concatenated, requiring only adler1, adler2, and len2. Note 1665 that the z_off_t type (like off_t) is a signed integer. If len2 is 1666 negative, the result has no meaning or utility. 1667 */ 1668 1669 ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len)); 1670 /* 1671 Update a running CRC-32 with the bytes buf[0..len-1] and return the 1672 updated CRC-32. If buf is Z_NULL, this function returns the required 1673 initial value for the crc. Pre- and post-conditioning (one's complement) is 1674 performed within this function so it shouldn't be done by the application. 1675 1676 Usage example: 1677 1678 uLong crc = crc32(0L, Z_NULL, 0); 1679 1680 while (read_buffer(buffer, length) != EOF) { 1681 crc = crc32(crc, buffer, length); 1682 } 1683 if (crc != original_crc) error(); 1684 */ 1685 1686 /* 1687 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2)); 1688 1689 Combine two CRC-32 check values into one. For two sequences of bytes, 1690 seq1 and seq2 with lengths len1 and len2, CRC-32 check values were 1691 calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32 1692 check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and 1693 len2. 1694 */ 1695 1696 1697 /* various hacks, don't look :) */ 1698 1699 /* deflateInit and inflateInit are macros to allow checking the zlib version 1700 * and the compiler's view of z_stream: 1701 */ 1702 ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level, 1703 const char *version, int stream_size)); 1704 ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm, 1705 const char *version, int stream_size)); 1706 ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method, 1707 int windowBits, int memLevel, 1708 int strategy, const char *version, 1709 int stream_size)); 1710 ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits, 1711 const char *version, int stream_size)); 1712 ZEXTERN int ZEXPORT inflateBackInit_ OF((z_streamp strm, int windowBits, 1713 unsigned char FAR *window, 1714 const char *version, 1715 int stream_size)); 1716 #define deflateInit(strm, level) \ 1717 deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream)) 1718 #define inflateInit(strm) \ 1719 inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream)) 1720 #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \ 1721 deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\ 1722 (strategy), ZLIB_VERSION, (int)sizeof(z_stream)) 1723 #define inflateInit2(strm, windowBits) \ 1724 inflateInit2_((strm), (windowBits), ZLIB_VERSION, \ 1725 (int)sizeof(z_stream)) 1726 #define inflateBackInit(strm, windowBits, window) \ 1727 inflateBackInit_((strm), (windowBits), (window), \ 1728 ZLIB_VERSION, (int)sizeof(z_stream)) 1729 1730 #ifndef Z_SOLO 1731 1732 /* gzgetc() macro and its supporting function and exposed data structure. Note 1733 * that the real internal state is much larger than the exposed structure. 1734 * This abbreviated structure exposes just enough for the gzgetc() macro. The 1735 * user should not mess with these exposed elements, since their names or 1736 * behavior could change in the future, perhaps even capriciously. They can 1737 * only be used by the gzgetc() macro. You have been warned. 1738 */ 1739 struct gzFile_s { 1740 unsigned have; 1741 unsigned char *next; 1742 z_off64_t pos; 1743 }; 1744 ZEXTERN int ZEXPORT gzgetc_ OF((gzFile file)); /* backward compatibility */ 1745 #ifdef Z_PREFIX_SET 1746 # undef z_gzgetc 1747 # define z_gzgetc(g) \ 1748 ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : gzgetc(g)) 1749 #else 1750 # define gzgetc(g) \ 1751 ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : gzgetc(g)) 1752 #endif 1753 1754 /* provide 64-bit offset functions if _LARGEFILE64_SOURCE defined, and/or 1755 * change the regular functions to 64 bits if _FILE_OFFSET_BITS is 64 (if 1756 * both are true, the application gets the *64 functions, and the regular 1757 * functions are changed to 64 bits) -- in case these are set on systems 1758 * without large file support, _LFS64_LARGEFILE must also be true 1759 */ 1760 #ifdef Z_LARGE64 1761 ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *)); 1762 ZEXTERN z_off64_t ZEXPORT gzseek64 OF((gzFile, z_off64_t, int)); 1763 ZEXTERN z_off64_t ZEXPORT gztell64 OF((gzFile)); 1764 ZEXTERN z_off64_t ZEXPORT gzoffset64 OF((gzFile)); 1765 ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off64_t)); 1766 ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off64_t)); 1767 #endif 1768 1769 #if !defined(ZLIB_INTERNAL) && defined(Z_WANT64) 1770 # ifdef Z_PREFIX_SET 1771 # define z_gzopen z_gzopen64 1772 # define z_gzseek z_gzseek64 1773 # define z_gztell z_gztell64 1774 # define z_gzoffset z_gzoffset64 1775 # define z_adler32_combine z_adler32_combine64 1776 # define z_crc32_combine z_crc32_combine64 1777 # else 1778 # define gzopen gzopen64 1779 # define gzseek gzseek64 1780 # define gztell gztell64 1781 # define gzoffset gzoffset64 1782 # undef adler32_combine 1783 # undef crc32_combine 1784 # define adler32_combine adler32_combine64 1785 # define crc32_combine crc32_combine64 1786 # endif 1787 # ifndef Z_LARGE64 1788 ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *)); 1789 ZEXTERN off64_t ZEXPORT gzseek64 OF((gzFile, off64_t, int)); 1790 ZEXTERN off64_t ZEXPORT gztell64 OF((gzFile)); 1791 ZEXTERN z_off64_t ZEXPORT gzoffset64 OF((gzFile)); 1792 ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, off64_t)); 1793 ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, off64_t)); 1794 # endif 1795 #else 1796 ZEXTERN gzFile ZEXPORT gzopen OF((const char *, const char *)); 1797 ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile, z_off_t, int)); 1798 ZEXTERN z_off_t ZEXPORT gztell OF((gzFile)); 1799 ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile)); 1800 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t)); 1801 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t)); 1802 #endif 1803 1804 #else /* Z_SOLO */ 1805 1806 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t)); 1807 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t)); 1808 1809 #endif /* !Z_SOLO */ 1810 1811 /* hack for buggy compilers */ 1812 #if !defined(ZUTIL_H) && !defined(NO_DUMMY_DECL) 1813 struct internal_state {int dummy;}; 1814 #endif 1815 1816 /* undocumented functions */ 1817 ZEXTERN const char * ZEXPORT zError OF((int)); 1818 ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp)); 1819 ZEXTERN const z_crc_t FAR * ZEXPORT get_crc_table OF((void)); 1820 ZEXTERN int ZEXPORT inflateUndermine OF((z_streamp, int)); 1821 ZEXTERN int ZEXPORT inflateResetKeep OF((z_streamp)); 1822 ZEXTERN int ZEXPORT deflateResetKeep OF((z_streamp)); 1823 #if defined(_WIN32) && !defined(Z_SOLO) 1824 ZEXTERN gzFile ZEXPORT gzopen_w OF((const wchar_t *path, 1825 const char *mode)); 1826 #endif 1827 #if defined(STDC) || defined(Z_HAVE_STDARG_H) 1828 # ifndef Z_SOLO 1829 ZEXTERN int ZEXPORTVA gzvprintf Z_ARG((gzFile file, 1830 const char *format, 1831 va_list va)); 1832 # endif 1833 #endif 1834 1835 #ifdef __cplusplus 1836 } 1837 #endif 1838 1839 #endif /* ZLIB_H */ 1840