zlib.h revision 1.6
1 /* $NetBSD: zlib.h,v 1.6 2022/10/15 19:49:32 christos Exp $ */ 2 3 /* zlib.h -- interface of the 'zlib' general purpose compression library 4 version 1.2.13, October 13th, 2022 5 6 Copyright (C) 1995-2022 Jean-loup Gailly and Mark Adler 7 8 This software is provided 'as-is', without any express or implied 9 warranty. In no event will the authors be held liable for any damages 10 arising from the use of this software. 11 12 Permission is granted to anyone to use this software for any purpose, 13 including commercial applications, and to alter it and redistribute it 14 freely, subject to the following restrictions: 15 16 1. The origin of this software must not be misrepresented; you must not 17 claim that you wrote the original software. If you use this software 18 in a product, an acknowledgment in the product documentation would be 19 appreciated but is not required. 20 2. Altered source versions must be plainly marked as such, and must not be 21 misrepresented as being the original software. 22 3. This notice may not be removed or altered from any source distribution. 23 24 Jean-loup Gailly Mark Adler 25 jloup (at) gzip.org madler (at) alumni.caltech.edu 26 27 28 The data format used by the zlib library is described by RFCs (Request for 29 Comments) 1950 to 1952 in the files http://tools.ietf.org/html/rfc1950 30 (zlib format), rfc1951 (deflate format) and rfc1952 (gzip format). 31 */ 32 33 #ifndef ZLIB_H 34 #define ZLIB_H 35 36 #include "zconf.h" 37 38 #ifdef __cplusplus 39 extern "C" { 40 #endif 41 42 #define ZLIB_VERSION "1.2.13" 43 #define ZLIB_VERNUM 0x12d0 44 #define ZLIB_VER_MAJOR 1 45 #define ZLIB_VER_MINOR 2 46 #define ZLIB_VER_REVISION 13 47 #define ZLIB_VER_SUBREVISION 0 48 49 /* 50 The 'zlib' compression library provides in-memory compression and 51 decompression functions, including integrity checks of the uncompressed data. 52 This version of the library supports only one compression method (deflation) 53 but other algorithms will be added later and will have the same stream 54 interface. 55 56 Compression can be done in a single step if the buffers are large enough, 57 or can be done by repeated calls of the compression function. In the latter 58 case, the application must provide more input and/or consume the output 59 (providing more output space) before each call. 60 61 The compressed data format used by default by the in-memory functions is 62 the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped 63 around a deflate stream, which is itself documented in RFC 1951. 64 65 The library also supports reading and writing files in gzip (.gz) format 66 with an interface similar to that of stdio using the functions that start 67 with "gz". The gzip format is different from the zlib format. gzip is a 68 gzip wrapper, documented in RFC 1952, wrapped around a deflate stream. 69 70 This library can optionally read and write gzip and raw deflate streams in 71 memory as well. 72 73 The zlib format was designed to be compact and fast for use in memory 74 and on communications channels. The gzip format was designed for single- 75 file compression on file systems, has a larger header than zlib to maintain 76 directory information, and uses a different, slower check method than zlib. 77 78 The library does not install any signal handler. The decoder checks 79 the consistency of the compressed data, so the library should never crash 80 even in the case of corrupted input. 81 */ 82 83 typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size)); 84 typedef void (*free_func) OF((voidpf opaque, voidpf address)); 85 86 struct internal_state; 87 88 typedef struct z_stream_s { 89 z_const Bytef *next_in; /* next input byte */ 90 uInt avail_in; /* number of bytes available at next_in */ 91 uLong total_in; /* total number of input bytes read so far */ 92 93 Bytef *next_out; /* next output byte will go here */ 94 uInt avail_out; /* remaining free space at next_out */ 95 uLong total_out; /* total number of bytes output so far */ 96 97 z_const char *msg; /* last error message, NULL if no error */ 98 struct internal_state FAR *state; /* not visible by applications */ 99 100 alloc_func zalloc; /* used to allocate the internal state */ 101 free_func zfree; /* used to free the internal state */ 102 voidpf opaque; /* private data object passed to zalloc and zfree */ 103 104 int data_type; /* best guess about the data type: binary or text 105 for deflate, or the decoding state for inflate */ 106 uLong adler; /* Adler-32 or CRC-32 value of the uncompressed data */ 107 uLong reserved; /* reserved for future use */ 108 } z_stream; 109 110 typedef z_stream FAR *z_streamp; 111 112 /* 113 gzip header information passed to and from zlib routines. See RFC 1952 114 for more details on the meanings of these fields. 115 */ 116 typedef struct gz_header_s { 117 int text; /* true if compressed data believed to be text */ 118 uLong time; /* modification time */ 119 int xflags; /* extra flags (not used when writing a gzip file) */ 120 int os; /* operating system */ 121 Bytef *extra; /* pointer to extra field or Z_NULL if none */ 122 uInt extra_len; /* extra field length (valid if extra != Z_NULL) */ 123 uInt extra_max; /* space at extra (only when reading header) */ 124 Bytef *name; /* pointer to zero-terminated file name or Z_NULL */ 125 uInt name_max; /* space at name (only when reading header) */ 126 Bytef *comment; /* pointer to zero-terminated comment or Z_NULL */ 127 uInt comm_max; /* space at comment (only when reading header) */ 128 int hcrc; /* true if there was or will be a header crc */ 129 int done; /* true when done reading gzip header (not used 130 when writing a gzip file) */ 131 } gz_header; 132 133 typedef gz_header FAR *gz_headerp; 134 135 /* 136 The application must update next_in and avail_in when avail_in has dropped 137 to zero. It must update next_out and avail_out when avail_out has dropped 138 to zero. The application must initialize zalloc, zfree and opaque before 139 calling the init function. All other fields are set by the compression 140 library and must not be updated by the application. 141 142 The opaque value provided by the application will be passed as the first 143 parameter for calls of zalloc and zfree. This can be useful for custom 144 memory management. The compression library attaches no meaning to the 145 opaque value. 146 147 zalloc must return Z_NULL if there is not enough memory for the object. 148 If zlib is used in a multi-threaded application, zalloc and zfree must be 149 thread safe. In that case, zlib is thread-safe. When zalloc and zfree are 150 Z_NULL on entry to the initialization function, they are set to internal 151 routines that use the standard library functions malloc() and free(). 152 153 On 16-bit systems, the functions zalloc and zfree must be able to allocate 154 exactly 65536 bytes, but will not be required to allocate more than this if 155 the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, pointers 156 returned by zalloc for objects of exactly 65536 bytes *must* have their 157 offset normalized to zero. The default allocation function provided by this 158 library ensures this (see zutil.c). To reduce memory requirements and avoid 159 any allocation of 64K objects, at the expense of compression ratio, compile 160 the library with -DMAX_WBITS=14 (see zconf.h). 161 162 The fields total_in and total_out can be used for statistics or progress 163 reports. After compression, total_in holds the total size of the 164 uncompressed data and may be saved for use by the decompressor (particularly 165 if the decompressor wants to decompress everything in a single step). 166 */ 167 168 /* constants */ 169 170 #define Z_NO_FLUSH 0 171 #define Z_PARTIAL_FLUSH 1 172 #define Z_SYNC_FLUSH 2 173 #define Z_FULL_FLUSH 3 174 #define Z_FINISH 4 175 #define Z_BLOCK 5 176 #define Z_TREES 6 177 /* Allowed flush values; see deflate() and inflate() below for details */ 178 179 #define Z_OK 0 180 #define Z_STREAM_END 1 181 #define Z_NEED_DICT 2 182 #define Z_ERRNO (-1) 183 #define Z_STREAM_ERROR (-2) 184 #define Z_DATA_ERROR (-3) 185 #define Z_MEM_ERROR (-4) 186 #define Z_BUF_ERROR (-5) 187 #define Z_VERSION_ERROR (-6) 188 /* Return codes for the compression/decompression functions. Negative values 189 * are errors, positive values are used for special but normal events. 190 */ 191 192 #define Z_NO_COMPRESSION 0 193 #define Z_BEST_SPEED 1 194 #define Z_BEST_COMPRESSION 9 195 #define Z_DEFAULT_COMPRESSION (-1) 196 /* compression levels */ 197 198 #define Z_FILTERED 1 199 #define Z_HUFFMAN_ONLY 2 200 #define Z_RLE 3 201 #define Z_FIXED 4 202 #define Z_DEFAULT_STRATEGY 0 203 /* compression strategy; see deflateInit2() below for details */ 204 205 #define Z_BINARY 0 206 #define Z_TEXT 1 207 #define Z_ASCII Z_TEXT /* for compatibility with 1.2.2 and earlier */ 208 #define Z_UNKNOWN 2 209 /* Possible values of the data_type field for deflate() */ 210 211 #define Z_DEFLATED 8 212 /* The deflate compression method (the only one supported in this version) */ 213 214 #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */ 215 216 #define zlib_version zlibVersion() 217 /* for compatibility with versions < 1.0.2 */ 218 219 220 /* basic functions */ 221 222 ZEXTERN const char * ZEXPORT zlibVersion OF((void)); 223 /* The application can compare zlibVersion and ZLIB_VERSION for consistency. 224 If the first character differs, the library code actually used is not 225 compatible with the zlib.h header file used by the application. This check 226 is automatically made by deflateInit and inflateInit. 227 */ 228 229 /* 230 ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level)); 231 232 Initializes the internal stream state for compression. The fields 233 zalloc, zfree and opaque must be initialized before by the caller. If 234 zalloc and zfree are set to Z_NULL, deflateInit updates them to use default 235 allocation functions. 236 237 The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9: 238 1 gives best speed, 9 gives best compression, 0 gives no compression at all 239 (the input data is simply copied a block at a time). Z_DEFAULT_COMPRESSION 240 requests a default compromise between speed and compression (currently 241 equivalent to level 6). 242 243 deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough 244 memory, Z_STREAM_ERROR if level is not a valid compression level, or 245 Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible 246 with the version assumed by the caller (ZLIB_VERSION). msg is set to null 247 if there is no error message. deflateInit does not perform any compression: 248 this will be done by deflate(). 249 */ 250 251 252 ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush)); 253 /* 254 deflate compresses as much data as possible, and stops when the input 255 buffer becomes empty or the output buffer becomes full. It may introduce 256 some output latency (reading input without producing any output) except when 257 forced to flush. 258 259 The detailed semantics are as follows. deflate performs one or both of the 260 following actions: 261 262 - Compress more input starting at next_in and update next_in and avail_in 263 accordingly. If not all input can be processed (because there is not 264 enough room in the output buffer), next_in and avail_in are updated and 265 processing will resume at this point for the next call of deflate(). 266 267 - Generate more output starting at next_out and update next_out and avail_out 268 accordingly. This action is forced if the parameter flush is non zero. 269 Forcing flush frequently degrades the compression ratio, so this parameter 270 should be set only when necessary. Some output may be provided even if 271 flush is zero. 272 273 Before the call of deflate(), the application should ensure that at least 274 one of the actions is possible, by providing more input and/or consuming more 275 output, and updating avail_in or avail_out accordingly; avail_out should 276 never be zero before the call. The application can consume the compressed 277 output when it wants, for example when the output buffer is full (avail_out 278 == 0), or after each call of deflate(). If deflate returns Z_OK and with 279 zero avail_out, it must be called again after making room in the output 280 buffer because there might be more output pending. See deflatePending(), 281 which can be used if desired to determine whether or not there is more output 282 in that case. 283 284 Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to 285 decide how much data to accumulate before producing output, in order to 286 maximize compression. 287 288 If the parameter flush is set to Z_SYNC_FLUSH, all pending output is 289 flushed to the output buffer and the output is aligned on a byte boundary, so 290 that the decompressor can get all input data available so far. (In 291 particular avail_in is zero after the call if enough output space has been 292 provided before the call.) Flushing may degrade compression for some 293 compression algorithms and so it should be used only when necessary. This 294 completes the current deflate block and follows it with an empty stored block 295 that is three bits plus filler bits to the next byte, followed by four bytes 296 (00 00 ff ff). 297 298 If flush is set to Z_PARTIAL_FLUSH, all pending output is flushed to the 299 output buffer, but the output is not aligned to a byte boundary. All of the 300 input data so far will be available to the decompressor, as for Z_SYNC_FLUSH. 301 This completes the current deflate block and follows it with an empty fixed 302 codes block that is 10 bits long. This assures that enough bytes are output 303 in order for the decompressor to finish the block before the empty fixed 304 codes block. 305 306 If flush is set to Z_BLOCK, a deflate block is completed and emitted, as 307 for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to 308 seven bits of the current block are held to be written as the next byte after 309 the next deflate block is completed. In this case, the decompressor may not 310 be provided enough bits at this point in order to complete decompression of 311 the data provided so far to the compressor. It may need to wait for the next 312 block to be emitted. This is for advanced applications that need to control 313 the emission of deflate blocks. 314 315 If flush is set to Z_FULL_FLUSH, all output is flushed as with 316 Z_SYNC_FLUSH, and the compression state is reset so that decompression can 317 restart from this point if previous compressed data has been damaged or if 318 random access is desired. Using Z_FULL_FLUSH too often can seriously degrade 319 compression. 320 321 If deflate returns with avail_out == 0, this function must be called again 322 with the same value of the flush parameter and more output space (updated 323 avail_out), until the flush is complete (deflate returns with non-zero 324 avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that 325 avail_out is greater than six to avoid repeated flush markers due to 326 avail_out == 0 on return. 327 328 If the parameter flush is set to Z_FINISH, pending input is processed, 329 pending output is flushed and deflate returns with Z_STREAM_END if there was 330 enough output space. If deflate returns with Z_OK or Z_BUF_ERROR, this 331 function must be called again with Z_FINISH and more output space (updated 332 avail_out) but no more input data, until it returns with Z_STREAM_END or an 333 error. After deflate has returned Z_STREAM_END, the only possible operations 334 on the stream are deflateReset or deflateEnd. 335 336 Z_FINISH can be used in the first deflate call after deflateInit if all the 337 compression is to be done in a single step. In order to complete in one 338 call, avail_out must be at least the value returned by deflateBound (see 339 below). Then deflate is guaranteed to return Z_STREAM_END. If not enough 340 output space is provided, deflate will not return Z_STREAM_END, and it must 341 be called again as described above. 342 343 deflate() sets strm->adler to the Adler-32 checksum of all input read 344 so far (that is, total_in bytes). If a gzip stream is being generated, then 345 strm->adler will be the CRC-32 checksum of the input read so far. (See 346 deflateInit2 below.) 347 348 deflate() may update strm->data_type if it can make a good guess about 349 the input data type (Z_BINARY or Z_TEXT). If in doubt, the data is 350 considered binary. This field is only for information purposes and does not 351 affect the compression algorithm in any manner. 352 353 deflate() returns Z_OK if some progress has been made (more input 354 processed or more output produced), Z_STREAM_END if all input has been 355 consumed and all output has been produced (only when flush is set to 356 Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example 357 if next_in or next_out was Z_NULL or the state was inadvertently written over 358 by the application), or Z_BUF_ERROR if no progress is possible (for example 359 avail_in or avail_out was zero). Note that Z_BUF_ERROR is not fatal, and 360 deflate() can be called again with more input and more output space to 361 continue compressing. 362 */ 363 364 365 ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm)); 366 /* 367 All dynamically allocated data structures for this stream are freed. 368 This function discards any unprocessed input and does not flush any pending 369 output. 370 371 deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the 372 stream state was inconsistent, Z_DATA_ERROR if the stream was freed 373 prematurely (some input or output was discarded). In the error case, msg 374 may be set but then points to a static string (which must not be 375 deallocated). 376 */ 377 378 379 /* 380 ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm)); 381 382 Initializes the internal stream state for decompression. The fields 383 next_in, avail_in, zalloc, zfree and opaque must be initialized before by 384 the caller. In the current version of inflate, the provided input is not 385 read or consumed. The allocation of a sliding window will be deferred to 386 the first call of inflate (if the decompression does not complete on the 387 first call). If zalloc and zfree are set to Z_NULL, inflateInit updates 388 them to use default allocation functions. 389 390 inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough 391 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the 392 version assumed by the caller, or Z_STREAM_ERROR if the parameters are 393 invalid, such as a null pointer to the structure. msg is set to null if 394 there is no error message. inflateInit does not perform any decompression. 395 Actual decompression will be done by inflate(). So next_in, and avail_in, 396 next_out, and avail_out are unused and unchanged. The current 397 implementation of inflateInit() does not process any header information -- 398 that is deferred until inflate() is called. 399 */ 400 401 402 ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush)); 403 /* 404 inflate decompresses as much data as possible, and stops when the input 405 buffer becomes empty or the output buffer becomes full. It may introduce 406 some output latency (reading input without producing any output) except when 407 forced to flush. 408 409 The detailed semantics are as follows. inflate performs one or both of the 410 following actions: 411 412 - Decompress more input starting at next_in and update next_in and avail_in 413 accordingly. If not all input can be processed (because there is not 414 enough room in the output buffer), then next_in and avail_in are updated 415 accordingly, and processing will resume at this point for the next call of 416 inflate(). 417 418 - Generate more output starting at next_out and update next_out and avail_out 419 accordingly. inflate() provides as much output as possible, until there is 420 no more input data or no more space in the output buffer (see below about 421 the flush parameter). 422 423 Before the call of inflate(), the application should ensure that at least 424 one of the actions is possible, by providing more input and/or consuming more 425 output, and updating the next_* and avail_* values accordingly. If the 426 caller of inflate() does not provide both available input and available 427 output space, it is possible that there will be no progress made. The 428 application can consume the uncompressed output when it wants, for example 429 when the output buffer is full (avail_out == 0), or after each call of 430 inflate(). If inflate returns Z_OK and with zero avail_out, it must be 431 called again after making room in the output buffer because there might be 432 more output pending. 433 434 The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, Z_FINISH, 435 Z_BLOCK, or Z_TREES. Z_SYNC_FLUSH requests that inflate() flush as much 436 output as possible to the output buffer. Z_BLOCK requests that inflate() 437 stop if and when it gets to the next deflate block boundary. When decoding 438 the zlib or gzip format, this will cause inflate() to return immediately 439 after the header and before the first block. When doing a raw inflate, 440 inflate() will go ahead and process the first block, and will return when it 441 gets to the end of that block, or when it runs out of data. 442 443 The Z_BLOCK option assists in appending to or combining deflate streams. 444 To assist in this, on return inflate() always sets strm->data_type to the 445 number of unused bits in the last byte taken from strm->next_in, plus 64 if 446 inflate() is currently decoding the last block in the deflate stream, plus 447 128 if inflate() returned immediately after decoding an end-of-block code or 448 decoding the complete header up to just before the first byte of the deflate 449 stream. The end-of-block will not be indicated until all of the uncompressed 450 data from that block has been written to strm->next_out. The number of 451 unused bits may in general be greater than seven, except when bit 7 of 452 data_type is set, in which case the number of unused bits will be less than 453 eight. data_type is set as noted here every time inflate() returns for all 454 flush options, and so can be used to determine the amount of currently 455 consumed input in bits. 456 457 The Z_TREES option behaves as Z_BLOCK does, but it also returns when the 458 end of each deflate block header is reached, before any actual data in that 459 block is decoded. This allows the caller to determine the length of the 460 deflate block header for later use in random access within a deflate block. 461 256 is added to the value of strm->data_type when inflate() returns 462 immediately after reaching the end of the deflate block header. 463 464 inflate() should normally be called until it returns Z_STREAM_END or an 465 error. However if all decompression is to be performed in a single step (a 466 single call of inflate), the parameter flush should be set to Z_FINISH. In 467 this case all pending input is processed and all pending output is flushed; 468 avail_out must be large enough to hold all of the uncompressed data for the 469 operation to complete. (The size of the uncompressed data may have been 470 saved by the compressor for this purpose.) The use of Z_FINISH is not 471 required to perform an inflation in one step. However it may be used to 472 inform inflate that a faster approach can be used for the single inflate() 473 call. Z_FINISH also informs inflate to not maintain a sliding window if the 474 stream completes, which reduces inflate's memory footprint. If the stream 475 does not complete, either because not all of the stream is provided or not 476 enough output space is provided, then a sliding window will be allocated and 477 inflate() can be called again to continue the operation as if Z_NO_FLUSH had 478 been used. 479 480 In this implementation, inflate() always flushes as much output as 481 possible to the output buffer, and always uses the faster approach on the 482 first call. So the effects of the flush parameter in this implementation are 483 on the return value of inflate() as noted below, when inflate() returns early 484 when Z_BLOCK or Z_TREES is used, and when inflate() avoids the allocation of 485 memory for a sliding window when Z_FINISH is used. 486 487 If a preset dictionary is needed after this call (see inflateSetDictionary 488 below), inflate sets strm->adler to the Adler-32 checksum of the dictionary 489 chosen by the compressor and returns Z_NEED_DICT; otherwise it sets 490 strm->adler to the Adler-32 checksum of all output produced so far (that is, 491 total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described 492 below. At the end of the stream, inflate() checks that its computed Adler-32 493 checksum is equal to that saved by the compressor and returns Z_STREAM_END 494 only if the checksum is correct. 495 496 inflate() can decompress and check either zlib-wrapped or gzip-wrapped 497 deflate data. The header type is detected automatically, if requested when 498 initializing with inflateInit2(). Any information contained in the gzip 499 header is not retained unless inflateGetHeader() is used. When processing 500 gzip-wrapped deflate data, strm->adler32 is set to the CRC-32 of the output 501 produced so far. The CRC-32 is checked against the gzip trailer, as is the 502 uncompressed length, modulo 2^32. 503 504 inflate() returns Z_OK if some progress has been made (more input processed 505 or more output produced), Z_STREAM_END if the end of the compressed data has 506 been reached and all uncompressed output has been produced, Z_NEED_DICT if a 507 preset dictionary is needed at this point, Z_DATA_ERROR if the input data was 508 corrupted (input stream not conforming to the zlib format or incorrect check 509 value, in which case strm->msg points to a string with a more specific 510 error), Z_STREAM_ERROR if the stream structure was inconsistent (for example 511 next_in or next_out was Z_NULL, or the state was inadvertently written over 512 by the application), Z_MEM_ERROR if there was not enough memory, Z_BUF_ERROR 513 if no progress was possible or if there was not enough room in the output 514 buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and 515 inflate() can be called again with more input and more output space to 516 continue decompressing. If Z_DATA_ERROR is returned, the application may 517 then call inflateSync() to look for a good compression block if a partial 518 recovery of the data is to be attempted. 519 */ 520 521 522 ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm)); 523 /* 524 All dynamically allocated data structures for this stream are freed. 525 This function discards any unprocessed input and does not flush any pending 526 output. 527 528 inflateEnd returns Z_OK if success, or Z_STREAM_ERROR if the stream state 529 was inconsistent. 530 */ 531 532 533 /* Advanced functions */ 534 535 /* 536 The following functions are needed only in some special applications. 537 */ 538 539 /* 540 ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm, 541 int level, 542 int method, 543 int windowBits, 544 int memLevel, 545 int strategy)); 546 547 This is another version of deflateInit with more compression options. The 548 fields zalloc, zfree and opaque must be initialized before by the caller. 549 550 The method parameter is the compression method. It must be Z_DEFLATED in 551 this version of the library. 552 553 The windowBits parameter is the base two logarithm of the window size 554 (the size of the history buffer). It should be in the range 8..15 for this 555 version of the library. Larger values of this parameter result in better 556 compression at the expense of memory usage. The default value is 15 if 557 deflateInit is used instead. 558 559 For the current implementation of deflate(), a windowBits value of 8 (a 560 window size of 256 bytes) is not supported. As a result, a request for 8 561 will result in 9 (a 512-byte window). In that case, providing 8 to 562 inflateInit2() will result in an error when the zlib header with 9 is 563 checked against the initialization of inflate(). The remedy is to not use 8 564 with deflateInit2() with this initialization, or at least in that case use 9 565 with inflateInit2(). 566 567 windowBits can also be -8..-15 for raw deflate. In this case, -windowBits 568 determines the window size. deflate() will then generate raw deflate data 569 with no zlib header or trailer, and will not compute a check value. 570 571 windowBits can also be greater than 15 for optional gzip encoding. Add 572 16 to windowBits to write a simple gzip header and trailer around the 573 compressed data instead of a zlib wrapper. The gzip header will have no 574 file name, no extra data, no comment, no modification time (set to zero), no 575 header crc, and the operating system will be set to the appropriate value, 576 if the operating system was determined at compile time. If a gzip stream is 577 being written, strm->adler is a CRC-32 instead of an Adler-32. 578 579 For raw deflate or gzip encoding, a request for a 256-byte window is 580 rejected as invalid, since only the zlib header provides a means of 581 transmitting the window size to the decompressor. 582 583 The memLevel parameter specifies how much memory should be allocated 584 for the internal compression state. memLevel=1 uses minimum memory but is 585 slow and reduces compression ratio; memLevel=9 uses maximum memory for 586 optimal speed. The default value is 8. See zconf.h for total memory usage 587 as a function of windowBits and memLevel. 588 589 The strategy parameter is used to tune the compression algorithm. Use the 590 value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a 591 filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no 592 string match), or Z_RLE to limit match distances to one (run-length 593 encoding). Filtered data consists mostly of small values with a somewhat 594 random distribution. In this case, the compression algorithm is tuned to 595 compress them better. The effect of Z_FILTERED is to force more Huffman 596 coding and less string matching; it is somewhat intermediate between 597 Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as 598 fast as Z_HUFFMAN_ONLY, but give better compression for PNG image data. The 599 strategy parameter only affects the compression ratio but not the 600 correctness of the compressed output even if it is not set appropriately. 601 Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler 602 decoder for special applications. 603 604 deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 605 memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid 606 method), or Z_VERSION_ERROR if the zlib library version (zlib_version) is 607 incompatible with the version assumed by the caller (ZLIB_VERSION). msg is 608 set to null if there is no error message. deflateInit2 does not perform any 609 compression: this will be done by deflate(). 610 */ 611 612 ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm, 613 const Bytef *dictionary, 614 uInt dictLength)); 615 /* 616 Initializes the compression dictionary from the given byte sequence 617 without producing any compressed output. When using the zlib format, this 618 function must be called immediately after deflateInit, deflateInit2 or 619 deflateReset, and before any call of deflate. When doing raw deflate, this 620 function must be called either before any call of deflate, or immediately 621 after the completion of a deflate block, i.e. after all input has been 622 consumed and all output has been delivered when using any of the flush 623 options Z_BLOCK, Z_PARTIAL_FLUSH, Z_SYNC_FLUSH, or Z_FULL_FLUSH. The 624 compressor and decompressor must use exactly the same dictionary (see 625 inflateSetDictionary). 626 627 The dictionary should consist of strings (byte sequences) that are likely 628 to be encountered later in the data to be compressed, with the most commonly 629 used strings preferably put towards the end of the dictionary. Using a 630 dictionary is most useful when the data to be compressed is short and can be 631 predicted with good accuracy; the data can then be compressed better than 632 with the default empty dictionary. 633 634 Depending on the size of the compression data structures selected by 635 deflateInit or deflateInit2, a part of the dictionary may in effect be 636 discarded, for example if the dictionary is larger than the window size 637 provided in deflateInit or deflateInit2. Thus the strings most likely to be 638 useful should be put at the end of the dictionary, not at the front. In 639 addition, the current implementation of deflate will use at most the window 640 size minus 262 bytes of the provided dictionary. 641 642 Upon return of this function, strm->adler is set to the Adler-32 value 643 of the dictionary; the decompressor may later use this value to determine 644 which dictionary has been used by the compressor. (The Adler-32 value 645 applies to the whole dictionary even if only a subset of the dictionary is 646 actually used by the compressor.) If a raw deflate was requested, then the 647 Adler-32 value is not computed and strm->adler is not set. 648 649 deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a 650 parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is 651 inconsistent (for example if deflate has already been called for this stream 652 or if not at a block boundary for raw deflate). deflateSetDictionary does 653 not perform any compression: this will be done by deflate(). 654 */ 655 656 ZEXTERN int ZEXPORT deflateGetDictionary OF((z_streamp strm, 657 Bytef *dictionary, 658 uInt *dictLength)); 659 /* 660 Returns the sliding dictionary being maintained by deflate. dictLength is 661 set to the number of bytes in the dictionary, and that many bytes are copied 662 to dictionary. dictionary must have enough space, where 32768 bytes is 663 always enough. If deflateGetDictionary() is called with dictionary equal to 664 Z_NULL, then only the dictionary length is returned, and nothing is copied. 665 Similarly, if dictLength is Z_NULL, then it is not set. 666 667 deflateGetDictionary() may return a length less than the window size, even 668 when more than the window size in input has been provided. It may return up 669 to 258 bytes less in that case, due to how zlib's implementation of deflate 670 manages the sliding window and lookahead for matches, where matches can be 671 up to 258 bytes long. If the application needs the last window-size bytes of 672 input, then that would need to be saved by the application outside of zlib. 673 674 deflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the 675 stream state is inconsistent. 676 */ 677 678 ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest, 679 z_streamp source)); 680 /* 681 Sets the destination stream as a complete copy of the source stream. 682 683 This function can be useful when several compression strategies will be 684 tried, for example when there are several ways of pre-processing the input 685 data with a filter. The streams that will be discarded should then be freed 686 by calling deflateEnd. Note that deflateCopy duplicates the internal 687 compression state which can be quite large, so this strategy is slow and can 688 consume lots of memory. 689 690 deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not 691 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent 692 (such as zalloc being Z_NULL). msg is left unchanged in both source and 693 destination. 694 */ 695 696 ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm)); 697 /* 698 This function is equivalent to deflateEnd followed by deflateInit, but 699 does not free and reallocate the internal compression state. The stream 700 will leave the compression level and any other attributes that may have been 701 set unchanged. 702 703 deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source 704 stream state was inconsistent (such as zalloc or state being Z_NULL). 705 */ 706 707 ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm, 708 int level, 709 int strategy)); 710 /* 711 Dynamically update the compression level and compression strategy. The 712 interpretation of level and strategy is as in deflateInit2(). This can be 713 used to switch between compression and straight copy of the input data, or 714 to switch to a different kind of input data requiring a different strategy. 715 If the compression approach (which is a function of the level) or the 716 strategy is changed, and if there have been any deflate() calls since the 717 state was initialized or reset, then the input available so far is 718 compressed with the old level and strategy using deflate(strm, Z_BLOCK). 719 There are three approaches for the compression levels 0, 1..3, and 4..9 720 respectively. The new level and strategy will take effect at the next call 721 of deflate(). 722 723 If a deflate(strm, Z_BLOCK) is performed by deflateParams(), and it does 724 not have enough output space to complete, then the parameter change will not 725 take effect. In this case, deflateParams() can be called again with the 726 same parameters and more output space to try again. 727 728 In order to assure a change in the parameters on the first try, the 729 deflate stream should be flushed using deflate() with Z_BLOCK or other flush 730 request until strm.avail_out is not zero, before calling deflateParams(). 731 Then no more input data should be provided before the deflateParams() call. 732 If this is done, the old level and strategy will be applied to the data 733 compressed before deflateParams(), and the new level and strategy will be 734 applied to the data compressed after deflateParams(). 735 736 deflateParams returns Z_OK on success, Z_STREAM_ERROR if the source stream 737 state was inconsistent or if a parameter was invalid, or Z_BUF_ERROR if 738 there was not enough output space to complete the compression of the 739 available input data before a change in the strategy or approach. Note that 740 in the case of a Z_BUF_ERROR, the parameters are not changed. A return 741 value of Z_BUF_ERROR is not fatal, in which case deflateParams() can be 742 retried with more output space. 743 */ 744 745 ZEXTERN int ZEXPORT deflateTune OF((z_streamp strm, 746 int good_length, 747 int max_lazy, 748 int nice_length, 749 int max_chain)); 750 /* 751 Fine tune deflate's internal compression parameters. This should only be 752 used by someone who understands the algorithm used by zlib's deflate for 753 searching for the best matching string, and even then only by the most 754 fanatic optimizer trying to squeeze out the last compressed bit for their 755 specific input data. Read the deflate.c source code for the meaning of the 756 max_lazy, good_length, nice_length, and max_chain parameters. 757 758 deflateTune() can be called after deflateInit() or deflateInit2(), and 759 returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream. 760 */ 761 762 ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm, 763 uLong sourceLen)); 764 /* 765 deflateBound() returns an upper bound on the compressed size after 766 deflation of sourceLen bytes. It must be called after deflateInit() or 767 deflateInit2(), and after deflateSetHeader(), if used. This would be used 768 to allocate an output buffer for deflation in a single pass, and so would be 769 called before deflate(). If that first deflate() call is provided the 770 sourceLen input bytes, an output buffer allocated to the size returned by 771 deflateBound(), and the flush value Z_FINISH, then deflate() is guaranteed 772 to return Z_STREAM_END. Note that it is possible for the compressed size to 773 be larger than the value returned by deflateBound() if flush options other 774 than Z_FINISH or Z_NO_FLUSH are used. 775 */ 776 777 ZEXTERN int ZEXPORT deflatePending OF((z_streamp strm, 778 unsigned *pending, 779 int *bits)); 780 /* 781 deflatePending() returns the number of bytes and bits of output that have 782 been generated, but not yet provided in the available output. The bytes not 783 provided would be due to the available output space having being consumed. 784 The number of bits of output not provided are between 0 and 7, where they 785 await more bits to join them in order to fill out a full byte. If pending 786 or bits are Z_NULL, then those values are not set. 787 788 deflatePending returns Z_OK if success, or Z_STREAM_ERROR if the source 789 stream state was inconsistent. 790 */ 791 792 ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm, 793 int bits, 794 int value)); 795 /* 796 deflatePrime() inserts bits in the deflate output stream. The intent 797 is that this function is used to start off the deflate output with the bits 798 leftover from a previous deflate stream when appending to it. As such, this 799 function can only be used for raw deflate, and must be used before the first 800 deflate() call after a deflateInit2() or deflateReset(). bits must be less 801 than or equal to 16, and that many of the least significant bits of value 802 will be inserted in the output. 803 804 deflatePrime returns Z_OK if success, Z_BUF_ERROR if there was not enough 805 room in the internal buffer to insert the bits, or Z_STREAM_ERROR if the 806 source stream state was inconsistent. 807 */ 808 809 ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm, 810 gz_headerp head)); 811 /* 812 deflateSetHeader() provides gzip header information for when a gzip 813 stream is requested by deflateInit2(). deflateSetHeader() may be called 814 after deflateInit2() or deflateReset() and before the first call of 815 deflate(). The text, time, os, extra field, name, and comment information 816 in the provided gz_header structure are written to the gzip header (xflag is 817 ignored -- the extra flags are set according to the compression level). The 818 caller must assure that, if not Z_NULL, name and comment are terminated with 819 a zero byte, and that if extra is not Z_NULL, that extra_len bytes are 820 available there. If hcrc is true, a gzip header crc is included. Note that 821 the current versions of the command-line version of gzip (up through version 822 1.3.x) do not support header crc's, and will report that it is a "multi-part 823 gzip file" and give up. 824 825 If deflateSetHeader is not used, the default gzip header has text false, 826 the time set to zero, and os set to 255, with no extra, name, or comment 827 fields. The gzip header is returned to the default state by deflateReset(). 828 829 deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source 830 stream state was inconsistent. 831 */ 832 833 /* 834 ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm, 835 int windowBits)); 836 837 This is another version of inflateInit with an extra parameter. The 838 fields next_in, avail_in, zalloc, zfree and opaque must be initialized 839 before by the caller. 840 841 The windowBits parameter is the base two logarithm of the maximum window 842 size (the size of the history buffer). It should be in the range 8..15 for 843 this version of the library. The default value is 15 if inflateInit is used 844 instead. windowBits must be greater than or equal to the windowBits value 845 provided to deflateInit2() while compressing, or it must be equal to 15 if 846 deflateInit2() was not used. If a compressed stream with a larger window 847 size is given as input, inflate() will return with the error code 848 Z_DATA_ERROR instead of trying to allocate a larger window. 849 850 windowBits can also be zero to request that inflate use the window size in 851 the zlib header of the compressed stream. 852 853 windowBits can also be -8..-15 for raw inflate. In this case, -windowBits 854 determines the window size. inflate() will then process raw deflate data, 855 not looking for a zlib or gzip header, not generating a check value, and not 856 looking for any check values for comparison at the end of the stream. This 857 is for use with other formats that use the deflate compressed data format 858 such as zip. Those formats provide their own check values. If a custom 859 format is developed using the raw deflate format for compressed data, it is 860 recommended that a check value such as an Adler-32 or a CRC-32 be applied to 861 the uncompressed data as is done in the zlib, gzip, and zip formats. For 862 most applications, the zlib format should be used as is. Note that comments 863 above on the use in deflateInit2() applies to the magnitude of windowBits. 864 865 windowBits can also be greater than 15 for optional gzip decoding. Add 866 32 to windowBits to enable zlib and gzip decoding with automatic header 867 detection, or add 16 to decode only the gzip format (the zlib format will 868 return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is a 869 CRC-32 instead of an Adler-32. Unlike the gunzip utility and gzread() (see 870 below), inflate() will *not* automatically decode concatenated gzip members. 871 inflate() will return Z_STREAM_END at the end of the gzip member. The state 872 would need to be reset to continue decoding a subsequent gzip member. This 873 *must* be done if there is more data after a gzip member, in order for the 874 decompression to be compliant with the gzip standard (RFC 1952). 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 Adler-32 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 Adler-32 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 Similarly, 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 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. If the window size is changed, then the 977 memory allocated for the window is freed, and the window will be reallocated 978 by inflate() if needed. 979 980 inflateReset2 returns Z_OK if success, or Z_STREAM_ERROR if the source 981 stream state was inconsistent (such as zalloc or state being Z_NULL), or if 982 the windowBits parameter is invalid. 983 */ 984 985 ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm, 986 int bits, 987 int value)); 988 /* 989 This function inserts bits in the inflate input stream. The intent is 990 that this function is used to start inflating at a bit position in the 991 middle of a byte. The provided bits will be used before any bytes are used 992 from next_in. This function should only be used with raw inflate, and 993 should be used before the first inflate() call after inflateInit2() or 994 inflateReset(). bits must be less than or equal to 16, and that many of the 995 least significant bits of value will be inserted in the input. 996 997 If bits is negative, then the input stream bit buffer is emptied. Then 998 inflatePrime() can be called again to put bits in the buffer. This is used 999 to clear out bits leftover after feeding inflate a block description prior 1000 to feeding inflate codes. 1001 1002 inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source 1003 stream state was inconsistent. 1004 */ 1005 1006 ZEXTERN long ZEXPORT inflateMark OF((z_streamp strm)); 1007 /* 1008 This function returns two values, one in the lower 16 bits of the return 1009 value, and the other in the remaining upper bits, obtained by shifting the 1010 return value down 16 bits. If the upper value is -1 and the lower value is 1011 zero, then inflate() is currently decoding information outside of a block. 1012 If the upper value is -1 and the lower value is non-zero, then inflate is in 1013 the middle of a stored block, with the lower value equaling the number of 1014 bytes from the input remaining to copy. If the upper value is not -1, then 1015 it is the number of bits back from the current bit position in the input of 1016 the code (literal or length/distance pair) currently being processed. In 1017 that case the lower value is the number of bytes already emitted for that 1018 code. 1019 1020 A code is being processed if inflate is waiting for more input to complete 1021 decoding of the code, or if it has completed decoding but is waiting for 1022 more output space to write the literal or match data. 1023 1024 inflateMark() is used to mark locations in the input data for random 1025 access, which may be at bit positions, and to note those cases where the 1026 output of a code may span boundaries of random access blocks. The current 1027 location in the input stream can be determined from avail_in and data_type 1028 as noted in the description for the Z_BLOCK flush parameter for inflate. 1029 1030 inflateMark returns the value noted above, or -65536 if the provided 1031 source stream state was inconsistent. 1032 */ 1033 1034 ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm, 1035 gz_headerp head)); 1036 /* 1037 inflateGetHeader() requests that gzip header information be stored in the 1038 provided gz_header structure. inflateGetHeader() may be called after 1039 inflateInit2() or inflateReset(), and before the first call of inflate(). 1040 As inflate() processes the gzip stream, head->done is zero until the header 1041 is completed, at which time head->done is set to one. If a zlib stream is 1042 being decoded, then head->done is set to -1 to indicate that there will be 1043 no gzip header information forthcoming. Note that Z_BLOCK or Z_TREES can be 1044 used to force inflate() to return immediately after header processing is 1045 complete and before any actual data is decompressed. 1046 1047 The text, time, xflags, and os fields are filled in with the gzip header 1048 contents. hcrc is set to true if there is a header CRC. (The header CRC 1049 was valid if done is set to one.) If extra is not Z_NULL, then extra_max 1050 contains the maximum number of bytes to write to extra. Once done is true, 1051 extra_len contains the actual extra field length, and extra contains the 1052 extra field, or that field truncated if extra_max is less than extra_len. 1053 If name is not Z_NULL, then up to name_max characters are written there, 1054 terminated with a zero unless the length is greater than name_max. If 1055 comment is not Z_NULL, then up to comm_max characters are written there, 1056 terminated with a zero unless the length is greater than comm_max. When any 1057 of extra, name, or comment are not Z_NULL and the respective field is not 1058 present in the header, then that field is set to Z_NULL to signal its 1059 absence. This allows the use of deflateSetHeader() with the returned 1060 structure to duplicate the header. However if those fields are set to 1061 allocated memory, then the application will need to save those pointers 1062 elsewhere so that they can be eventually freed. 1063 1064 If inflateGetHeader is not used, then the header information is simply 1065 discarded. The header is always checked for validity, including the header 1066 CRC if present. inflateReset() will reset the process to discard the header 1067 information. The application would need to call inflateGetHeader() again to 1068 retrieve the header from the next gzip stream. 1069 1070 inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source 1071 stream state was inconsistent. 1072 */ 1073 1074 /* 1075 ZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits, 1076 unsigned char FAR *window)); 1077 1078 Initialize the internal stream state for decompression using inflateBack() 1079 calls. The fields zalloc, zfree and opaque in strm must be initialized 1080 before the call. If zalloc and zfree are Z_NULL, then the default library- 1081 derived memory allocation routines are used. windowBits is the base two 1082 logarithm of the window size, in the range 8..15. window is a caller 1083 supplied buffer of that size. Except for special applications where it is 1084 assured that deflate was used with small window sizes, windowBits must be 15 1085 and a 32K byte window must be supplied to be able to decompress general 1086 deflate streams. 1087 1088 See inflateBack() for the usage of these routines. 1089 1090 inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of 1091 the parameters are invalid, Z_MEM_ERROR if the internal state could not be 1092 allocated, or Z_VERSION_ERROR if the version of the library does not match 1093 the version of the header file. 1094 */ 1095 1096 typedef unsigned (*in_func) OF((void FAR *, 1097 z_const unsigned char FAR * FAR *)); 1098 typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned)); 1099 1100 ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm, 1101 in_func in, void FAR *in_desc, 1102 out_func out, void FAR *out_desc)); 1103 /* 1104 inflateBack() does a raw inflate with a single call using a call-back 1105 interface for input and output. This is potentially more efficient than 1106 inflate() for file i/o applications, in that it avoids copying between the 1107 output and the sliding window by simply making the window itself the output 1108 buffer. inflate() can be faster on modern CPUs when used with large 1109 buffers. inflateBack() trusts the application to not change the output 1110 buffer passed by the output function, at least until inflateBack() returns. 1111 1112 inflateBackInit() must be called first to allocate the internal state 1113 and to initialize the state with the user-provided window buffer. 1114 inflateBack() may then be used multiple times to inflate a complete, raw 1115 deflate stream with each call. inflateBackEnd() is then called to free the 1116 allocated state. 1117 1118 A raw deflate stream is one with no zlib or gzip header or trailer. 1119 This routine would normally be used in a utility that reads zip or gzip 1120 files and writes out uncompressed files. The utility would decode the 1121 header and process the trailer on its own, hence this routine expects only 1122 the raw deflate stream to decompress. This is different from the default 1123 behavior of inflate(), which expects a zlib header and trailer around the 1124 deflate stream. 1125 1126 inflateBack() uses two subroutines supplied by the caller that are then 1127 called by inflateBack() for input and output. inflateBack() calls those 1128 routines until it reads a complete deflate stream and writes out all of the 1129 uncompressed data, or until it encounters an error. The function's 1130 parameters and return types are defined above in the in_func and out_func 1131 typedefs. inflateBack() will call in(in_desc, &buf) which should return the 1132 number of bytes of provided input, and a pointer to that input in buf. If 1133 there is no input available, in() must return zero -- buf is ignored in that 1134 case -- and inflateBack() will return a buffer error. inflateBack() will 1135 call out(out_desc, buf, len) to write the uncompressed data buf[0..len-1]. 1136 out() should return zero on success, or non-zero on failure. If out() 1137 returns non-zero, inflateBack() will return with an error. Neither in() nor 1138 out() are permitted to change the contents of the window provided to 1139 inflateBackInit(), which is also the buffer that out() uses to write from. 1140 The length written by out() will be at most the window size. Any non-zero 1141 amount of input may be provided by in(). 1142 1143 For convenience, inflateBack() can be provided input on the first call by 1144 setting strm->next_in and strm->avail_in. If that input is exhausted, then 1145 in() will be called. Therefore strm->next_in must be initialized before 1146 calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called 1147 immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in 1148 must also be initialized, and then if strm->avail_in is not zero, input will 1149 initially be taken from strm->next_in[0 .. strm->avail_in - 1]. 1150 1151 The in_desc and out_desc parameters of inflateBack() is passed as the 1152 first parameter of in() and out() respectively when they are called. These 1153 descriptors can be optionally used to pass any information that the caller- 1154 supplied in() and out() functions need to do their job. 1155 1156 On return, inflateBack() will set strm->next_in and strm->avail_in to 1157 pass back any unused input that was provided by the last in() call. The 1158 return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR 1159 if in() or out() returned an error, Z_DATA_ERROR if there was a format error 1160 in the deflate stream (in which case strm->msg is set to indicate the nature 1161 of the error), or Z_STREAM_ERROR if the stream was not properly initialized. 1162 In the case of Z_BUF_ERROR, an input or output error can be distinguished 1163 using strm->next_in which will be Z_NULL only if in() returned an error. If 1164 strm->next_in is not Z_NULL, then the Z_BUF_ERROR was due to out() returning 1165 non-zero. (in() will always be called before out(), so strm->next_in is 1166 assured to be defined if out() returns non-zero.) Note that inflateBack() 1167 cannot return Z_OK. 1168 */ 1169 1170 ZEXTERN int ZEXPORT inflateBackEnd OF((z_streamp strm)); 1171 /* 1172 All memory allocated by inflateBackInit() is freed. 1173 1174 inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream 1175 state was inconsistent. 1176 */ 1177 1178 ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void)); 1179 /* Return flags indicating compile-time options. 1180 1181 Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other: 1182 1.0: size of uInt 1183 3.2: size of uLong 1184 5.4: size of voidpf (pointer) 1185 7.6: size of z_off_t 1186 1187 Compiler, assembler, and debug options: 1188 8: ZLIB_DEBUG 1189 9: ASMV or ASMINF -- use ASM code 1190 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention 1191 11: 0 (reserved) 1192 1193 One-time table building (smaller code, but not thread-safe if true): 1194 12: BUILDFIXED -- build static block decoding tables when needed 1195 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed 1196 14,15: 0 (reserved) 1197 1198 Library content (indicates missing functionality): 1199 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking 1200 deflate code when not needed) 1201 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect 1202 and decode gzip streams (to avoid linking crc code) 1203 18-19: 0 (reserved) 1204 1205 Operation variations (changes in library functionality): 1206 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate 1207 21: FASTEST -- deflate algorithm with only one, lowest compression level 1208 22,23: 0 (reserved) 1209 1210 The sprintf variant used by gzprintf (zero is best): 1211 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format 1212 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure! 1213 26: 0 = returns value, 1 = void -- 1 means inferred string length returned 1214 1215 Remainder: 1216 27-31: 0 (reserved) 1217 */ 1218 1219 #ifndef Z_SOLO 1220 1221 /* utility functions */ 1222 1223 /* 1224 The following utility functions are implemented on top of the basic 1225 stream-oriented functions. To simplify the interface, some default options 1226 are assumed (compression level and memory usage, standard memory allocation 1227 functions). The source code of these utility functions can be modified if 1228 you need special options. 1229 */ 1230 1231 ZEXTERN int ZEXPORT compress OF((Bytef *dest, uLongf *destLen, 1232 const Bytef *source, uLong sourceLen)); 1233 /* 1234 Compresses the source buffer into the destination buffer. sourceLen is 1235 the byte length of the source buffer. Upon entry, destLen is the total size 1236 of the destination buffer, which must be at least the value returned by 1237 compressBound(sourceLen). Upon exit, destLen is the actual size of the 1238 compressed data. compress() is equivalent to compress2() with a level 1239 parameter of Z_DEFAULT_COMPRESSION. 1240 1241 compress returns Z_OK if success, Z_MEM_ERROR if there was not 1242 enough memory, Z_BUF_ERROR if there was not enough room in the output 1243 buffer. 1244 */ 1245 1246 ZEXTERN int ZEXPORT compress2 OF((Bytef *dest, uLongf *destLen, 1247 const Bytef *source, uLong sourceLen, 1248 int level)); 1249 /* 1250 Compresses the source buffer into the destination buffer. The level 1251 parameter has the same meaning as in deflateInit. sourceLen is the byte 1252 length of the source buffer. Upon entry, destLen is the total size of the 1253 destination buffer, which must be at least the value returned by 1254 compressBound(sourceLen). Upon exit, destLen is the actual size of the 1255 compressed data. 1256 1257 compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 1258 memory, Z_BUF_ERROR if there was not enough room in the output buffer, 1259 Z_STREAM_ERROR if the level parameter is invalid. 1260 */ 1261 1262 ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen)); 1263 /* 1264 compressBound() returns an upper bound on the compressed size after 1265 compress() or compress2() on sourceLen bytes. It would be used before a 1266 compress() or compress2() call to allocate the destination buffer. 1267 */ 1268 1269 ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen, 1270 const Bytef *source, uLong sourceLen)); 1271 /* 1272 Decompresses the source buffer into the destination buffer. sourceLen is 1273 the byte length of the source buffer. Upon entry, destLen is the total size 1274 of the destination buffer, which must be large enough to hold the entire 1275 uncompressed data. (The size of the uncompressed data must have been saved 1276 previously by the compressor and transmitted to the decompressor by some 1277 mechanism outside the scope of this compression library.) Upon exit, destLen 1278 is the actual size of the uncompressed data. 1279 1280 uncompress returns Z_OK if success, Z_MEM_ERROR if there was not 1281 enough memory, Z_BUF_ERROR if there was not enough room in the output 1282 buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete. In 1283 the case where there is not enough room, uncompress() will fill the output 1284 buffer with the uncompressed data up to that point. 1285 */ 1286 1287 ZEXTERN int ZEXPORT uncompress2 OF((Bytef *dest, uLongf *destLen, 1288 const Bytef *source, uLong *sourceLen)); 1289 /* 1290 Same as uncompress, except that sourceLen is a pointer, where the 1291 length of the source is *sourceLen. On return, *sourceLen is the number of 1292 source bytes consumed. 1293 */ 1294 1295 /* gzip file access functions */ 1296 1297 /* 1298 This library supports reading and writing files in gzip (.gz) format with 1299 an interface similar to that of stdio, using the functions that start with 1300 "gz". The gzip format is different from the zlib format. gzip is a gzip 1301 wrapper, documented in RFC 1952, wrapped around a deflate stream. 1302 */ 1303 1304 typedef struct gzFile_s *gzFile; /* semi-opaque gzip file descriptor */ 1305 1306 /* 1307 ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode)); 1308 1309 Open the gzip (.gz) file at path for reading and decompressing, or 1310 compressing and writing. The mode parameter is as in fopen ("rb" or "wb") 1311 but can also include a compression level ("wb9") or a strategy: 'f' for 1312 filtered data as in "wb6f", 'h' for Huffman-only compression as in "wb1h", 1313 'R' for run-length encoding as in "wb1R", or 'F' for fixed code compression 1314 as in "wb9F". (See the description of deflateInit2 for more information 1315 about the strategy parameter.) 'T' will request transparent writing or 1316 appending with no compression and not using the gzip format. 1317 1318 "a" can be used instead of "w" to request that the gzip stream that will 1319 be written be appended to the file. "+" will result in an error, since 1320 reading and writing to the same gzip file is not supported. The addition of 1321 "x" when writing will create the file exclusively, which fails if the file 1322 already exists. On systems that support it, the addition of "e" when 1323 reading or writing will set the flag to close the file on an execve() call. 1324 1325 These functions, as well as gzip, will read and decode a sequence of gzip 1326 streams in a file. The append function of gzopen() can be used to create 1327 such a file. (Also see gzflush() for another way to do this.) When 1328 appending, gzopen does not test whether the file begins with a gzip stream, 1329 nor does it look for the end of the gzip streams to begin appending. gzopen 1330 will simply append a gzip stream to the existing file. 1331 1332 gzopen can be used to read a file which is not in gzip format; in this 1333 case gzread will directly read from the file without decompression. When 1334 reading, this will be detected automatically by looking for the magic two- 1335 byte gzip header. 1336 1337 gzopen returns NULL if the file could not be opened, if there was 1338 insufficient memory to allocate the gzFile state, or if an invalid mode was 1339 specified (an 'r', 'w', or 'a' was not provided, or '+' was provided). 1340 errno can be checked to determine if the reason gzopen failed was that the 1341 file could not be opened. 1342 */ 1343 1344 ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode)); 1345 /* 1346 Associate a gzFile with the file descriptor fd. File descriptors are 1347 obtained from calls like open, dup, creat, pipe or fileno (if the file has 1348 been previously opened with fopen). The mode parameter is as in gzopen. 1349 1350 The next call of gzclose on the returned gzFile will also close the file 1351 descriptor fd, just like fclose(fdopen(fd, mode)) closes the file descriptor 1352 fd. If you want to keep fd open, use fd = dup(fd_keep); gz = gzdopen(fd, 1353 mode);. The duplicated descriptor should be saved to avoid a leak, since 1354 gzdopen does not close fd if it fails. If you are using fileno() to get the 1355 file descriptor from a FILE *, then you will have to use dup() to avoid 1356 double-close()ing the file descriptor. Both gzclose() and fclose() will 1357 close the associated file descriptor, so they need to have different file 1358 descriptors. 1359 1360 gzdopen returns NULL if there was insufficient memory to allocate the 1361 gzFile state, if an invalid mode was specified (an 'r', 'w', or 'a' was not 1362 provided, or '+' was provided), or if fd is -1. The file descriptor is not 1363 used until the next gz* read, write, seek, or close operation, so gzdopen 1364 will not detect if fd is invalid (unless fd is -1). 1365 */ 1366 1367 ZEXTERN int ZEXPORT gzbuffer OF((gzFile file, unsigned size)); 1368 /* 1369 Set the internal buffer size used by this library's functions for file to 1370 size. The default buffer size is 8192 bytes. This function must be called 1371 after gzopen() or gzdopen(), and before any other calls that read or write 1372 the file. The buffer memory allocation is always deferred to the first read 1373 or write. Three times that size in buffer space is allocated. A larger 1374 buffer size of, for example, 64K or 128K bytes will noticeably increase the 1375 speed of decompression (reading). 1376 1377 The new buffer size also affects the maximum length for gzprintf(). 1378 1379 gzbuffer() returns 0 on success, or -1 on failure, such as being called 1380 too late. 1381 */ 1382 1383 ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy)); 1384 /* 1385 Dynamically update the compression level and strategy for file. See the 1386 description of deflateInit2 for the meaning of these parameters. Previously 1387 provided data is flushed before applying the parameter changes. 1388 1389 gzsetparams returns Z_OK if success, Z_STREAM_ERROR if the file was not 1390 opened for writing, Z_ERRNO if there is an error writing the flushed data, 1391 or Z_MEM_ERROR if there is a memory allocation error. 1392 */ 1393 1394 ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len)); 1395 /* 1396 Read and decompress up to len uncompressed bytes from file into buf. If 1397 the input file is not in gzip format, gzread copies the given number of 1398 bytes into the buffer directly from the file. 1399 1400 After reaching the end of a gzip stream in the input, gzread will continue 1401 to read, looking for another gzip stream. Any number of gzip streams may be 1402 concatenated in the input file, and will all be decompressed by gzread(). 1403 If something other than a gzip stream is encountered after a gzip stream, 1404 that remaining trailing garbage is ignored (and no error is returned). 1405 1406 gzread can be used to read a gzip file that is being concurrently written. 1407 Upon reaching the end of the input, gzread will return with the available 1408 data. If the error code returned by gzerror is Z_OK or Z_BUF_ERROR, then 1409 gzclearerr can be used to clear the end of file indicator in order to permit 1410 gzread to be tried again. Z_OK indicates that a gzip stream was completed 1411 on the last gzread. Z_BUF_ERROR indicates that the input file ended in the 1412 middle of a gzip stream. Note that gzread does not return -1 in the event 1413 of an incomplete gzip stream. This error is deferred until gzclose(), which 1414 will return Z_BUF_ERROR if the last gzread ended in the middle of a gzip 1415 stream. Alternatively, gzerror can be used before gzclose to detect this 1416 case. 1417 1418 gzread returns the number of uncompressed bytes actually read, less than 1419 len for end of file, or -1 for error. If len is too large to fit in an int, 1420 then nothing is read, -1 is returned, and the error state is set to 1421 Z_STREAM_ERROR. 1422 */ 1423 1424 ZEXTERN z_size_t ZEXPORT gzfread OF((voidp buf, z_size_t size, z_size_t nitems, 1425 gzFile file)); 1426 /* 1427 Read and decompress up to nitems items of size size from file into buf, 1428 otherwise operating as gzread() does. This duplicates the interface of 1429 stdio's fread(), with size_t request and return types. If the library 1430 defines size_t, then z_size_t is identical to size_t. If not, then z_size_t 1431 is an unsigned integer type that can contain a pointer. 1432 1433 gzfread() returns the number of full items read of size size, or zero if 1434 the end of the file was reached and a full item could not be read, or if 1435 there was an error. gzerror() must be consulted if zero is returned in 1436 order to determine if there was an error. If the multiplication of size and 1437 nitems overflows, i.e. the product does not fit in a z_size_t, then nothing 1438 is read, zero is returned, and the error state is set to Z_STREAM_ERROR. 1439 1440 In the event that the end of file is reached and only a partial item is 1441 available at the end, i.e. the remaining uncompressed data length is not a 1442 multiple of size, then the final partial item is nevertheless read into buf 1443 and the end-of-file flag is set. The length of the partial item read is not 1444 provided, but could be inferred from the result of gztell(). This behavior 1445 is the same as the behavior of fread() implementations in common libraries, 1446 but it prevents the direct use of gzfread() to read a concurrently written 1447 file, resetting and retrying on end-of-file, when size is not 1. 1448 */ 1449 1450 ZEXTERN int ZEXPORT gzwrite OF((gzFile file, voidpc buf, unsigned len)); 1451 /* 1452 Compress and write the len uncompressed bytes at buf to file. gzwrite 1453 returns the number of uncompressed bytes written or 0 in case of error. 1454 */ 1455 1456 ZEXTERN z_size_t ZEXPORT gzfwrite OF((voidpc buf, z_size_t size, 1457 z_size_t nitems, gzFile file)); 1458 /* 1459 Compress and write nitems items of size size from buf to file, duplicating 1460 the interface of stdio's fwrite(), with size_t request and return types. If 1461 the library defines size_t, then z_size_t is identical to size_t. If not, 1462 then z_size_t is an unsigned integer type that can contain a pointer. 1463 1464 gzfwrite() returns the number of full items written of size size, or zero 1465 if there was an error. If the multiplication of size and nitems overflows, 1466 i.e. the product does not fit in a z_size_t, then nothing is written, zero 1467 is returned, and the error state is set to Z_STREAM_ERROR. 1468 */ 1469 1470 ZEXTERN int ZEXPORTVA gzprintf Z_ARG((gzFile file, const char *format, ...)); 1471 /* 1472 Convert, format, compress, and write the arguments (...) to file under 1473 control of the string format, as in fprintf. gzprintf returns the number of 1474 uncompressed bytes actually written, or a negative zlib error code in case 1475 of error. The number of uncompressed bytes written is limited to 8191, or 1476 one less than the buffer size given to gzbuffer(). The caller should assure 1477 that this limit is not exceeded. If it is exceeded, then gzprintf() will 1478 return an error (0) with nothing written. In this case, there may also be a 1479 buffer overflow with unpredictable consequences, which is possible only if 1480 zlib was compiled with the insecure functions sprintf() or vsprintf(), 1481 because the secure snprintf() or vsnprintf() functions were not available. 1482 This can be determined using zlibCompileFlags(). 1483 */ 1484 1485 ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s)); 1486 /* 1487 Compress and write the given null-terminated string s to file, excluding 1488 the terminating null character. 1489 1490 gzputs returns the number of characters written, or -1 in case of error. 1491 */ 1492 1493 ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len)); 1494 /* 1495 Read and decompress bytes from file into buf, until len-1 characters are 1496 read, or until a newline character is read and transferred to buf, or an 1497 end-of-file condition is encountered. If any characters are read or if len 1498 is one, the string is terminated with a null character. If no characters 1499 are read due to an end-of-file or len is less than one, then the buffer is 1500 left untouched. 1501 1502 gzgets returns buf which is a null-terminated string, or it returns NULL 1503 for end-of-file or in case of error. If there was an error, the contents at 1504 buf are indeterminate. 1505 */ 1506 1507 ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c)); 1508 /* 1509 Compress and write c, converted to an unsigned char, into file. gzputc 1510 returns the value that was written, or -1 in case of error. 1511 */ 1512 1513 ZEXTERN int ZEXPORT gzgetc OF((gzFile file)); 1514 /* 1515 Read and decompress one byte from file. gzgetc returns this byte or -1 1516 in case of end of file or error. This is implemented as a macro for speed. 1517 As such, it does not do all of the checking the other functions do. I.e. 1518 it does not check to see if file is NULL, nor whether the structure file 1519 points to has been clobbered or not. 1520 */ 1521 1522 ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file)); 1523 /* 1524 Push c back onto the stream for file to be read as the first character on 1525 the next read. At least one character of push-back is always allowed. 1526 gzungetc() returns the character pushed, or -1 on failure. gzungetc() will 1527 fail if c is -1, and may fail if a character has been pushed but not read 1528 yet. If gzungetc is used immediately after gzopen or gzdopen, at least the 1529 output buffer size of pushed characters is allowed. (See gzbuffer above.) 1530 The pushed character will be discarded if the stream is repositioned with 1531 gzseek() or gzrewind(). 1532 */ 1533 1534 ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush)); 1535 /* 1536 Flush all pending output to file. The parameter flush is as in the 1537 deflate() function. The return value is the zlib error number (see function 1538 gzerror below). gzflush is only permitted when writing. 1539 1540 If the flush parameter is Z_FINISH, the remaining data is written and the 1541 gzip stream is completed in the output. If gzwrite() is called again, a new 1542 gzip stream will be started in the output. gzread() is able to read such 1543 concatenated gzip streams. 1544 1545 gzflush should be called only when strictly necessary because it will 1546 degrade compression if called too often. 1547 */ 1548 1549 /* 1550 ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file, 1551 z_off_t offset, int whence)); 1552 1553 Set the starting position to offset relative to whence for the next gzread 1554 or gzwrite on file. The offset represents a number of bytes in the 1555 uncompressed data stream. The whence parameter is defined as in lseek(2); 1556 the value SEEK_END is not supported. 1557 1558 If the file is opened for reading, this function is emulated but can be 1559 extremely slow. If the file is opened for writing, only forward seeks are 1560 supported; gzseek then compresses a sequence of zeroes up to the new 1561 starting position. 1562 1563 gzseek returns the resulting offset location as measured in bytes from 1564 the beginning of the uncompressed stream, or -1 in case of error, in 1565 particular if the file is opened for writing and the new starting position 1566 would be before the current position. 1567 */ 1568 1569 ZEXTERN int ZEXPORT gzrewind OF((gzFile file)); 1570 /* 1571 Rewind file. This function is supported only for reading. 1572 1573 gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET). 1574 */ 1575 1576 /* 1577 ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file)); 1578 1579 Return the starting position for the next gzread or gzwrite on file. 1580 This position represents a number of bytes in the uncompressed data stream, 1581 and is zero when starting, even if appending or reading a gzip stream from 1582 the middle of a file using gzdopen(). 1583 1584 gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR) 1585 */ 1586 1587 /* 1588 ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile file)); 1589 1590 Return the current compressed (actual) read or write offset of file. This 1591 offset includes the count of bytes that precede the gzip stream, for example 1592 when appending or when using gzdopen() for reading. When reading, the 1593 offset does not include as yet unused buffered input. This information can 1594 be used for a progress indicator. On error, gzoffset() returns -1. 1595 */ 1596 1597 ZEXTERN int ZEXPORT gzeof OF((gzFile file)); 1598 /* 1599 Return true (1) if the end-of-file indicator for file has been set while 1600 reading, false (0) otherwise. Note that the end-of-file indicator is set 1601 only if the read tried to go past the end of the input, but came up short. 1602 Therefore, just like feof(), gzeof() may return false even if there is no 1603 more data to read, in the event that the last read request was for the exact 1604 number of bytes remaining in the input file. This will happen if the input 1605 file size is an exact multiple of the buffer size. 1606 1607 If gzeof() returns true, then the read functions will return no more data, 1608 unless the end-of-file indicator is reset by gzclearerr() and the input file 1609 has grown since the previous end of file was detected. 1610 */ 1611 1612 ZEXTERN int ZEXPORT gzdirect OF((gzFile file)); 1613 /* 1614 Return true (1) if file is being copied directly while reading, or false 1615 (0) if file is a gzip stream being decompressed. 1616 1617 If the input file is empty, gzdirect() will return true, since the input 1618 does not contain a gzip stream. 1619 1620 If gzdirect() is used immediately after gzopen() or gzdopen() it will 1621 cause buffers to be allocated to allow reading the file to determine if it 1622 is a gzip file. Therefore if gzbuffer() is used, it should be called before 1623 gzdirect(). 1624 1625 When writing, gzdirect() returns true (1) if transparent writing was 1626 requested ("wT" for the gzopen() mode), or false (0) otherwise. (Note: 1627 gzdirect() is not needed when writing. Transparent writing must be 1628 explicitly requested, so the application already knows the answer. When 1629 linking statically, using gzdirect() will include all of the zlib code for 1630 gzip file reading and decompression, which may not be desired.) 1631 */ 1632 1633 ZEXTERN int ZEXPORT gzclose OF((gzFile file)); 1634 /* 1635 Flush all pending output for file, if necessary, close file and 1636 deallocate the (de)compression state. Note that once file is closed, you 1637 cannot call gzerror with file, since its structures have been deallocated. 1638 gzclose must not be called more than once on the same file, just as free 1639 must not be called more than once on the same allocation. 1640 1641 gzclose will return Z_STREAM_ERROR if file is not valid, Z_ERRNO on a 1642 file operation error, Z_MEM_ERROR if out of memory, Z_BUF_ERROR if the 1643 last read ended in the middle of a gzip stream, or Z_OK on success. 1644 */ 1645 1646 ZEXTERN int ZEXPORT gzclose_r OF((gzFile file)); 1647 ZEXTERN int ZEXPORT gzclose_w OF((gzFile file)); 1648 /* 1649 Same as gzclose(), but gzclose_r() is only for use when reading, and 1650 gzclose_w() is only for use when writing or appending. The advantage to 1651 using these instead of gzclose() is that they avoid linking in zlib 1652 compression or decompression code that is not used when only reading or only 1653 writing respectively. If gzclose() is used, then both compression and 1654 decompression code will be included the application when linking to a static 1655 zlib library. 1656 */ 1657 1658 ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum)); 1659 /* 1660 Return the error message for the last error which occurred on file. 1661 errnum is set to zlib error number. If an error occurred in the file system 1662 and not in the compression library, errnum is set to Z_ERRNO and the 1663 application may consult errno to get the exact error code. 1664 1665 The application must not modify the returned string. Future calls to 1666 this function may invalidate the previously returned string. If file is 1667 closed, then the string previously returned by gzerror will no longer be 1668 available. 1669 1670 gzerror() should be used to distinguish errors from end-of-file for those 1671 functions above that do not distinguish those cases in their return values. 1672 */ 1673 1674 ZEXTERN void ZEXPORT gzclearerr OF((gzFile file)); 1675 /* 1676 Clear the error and end-of-file flags for file. This is analogous to the 1677 clearerr() function in stdio. This is useful for continuing to read a gzip 1678 file that is being written concurrently. 1679 */ 1680 1681 #endif /* !Z_SOLO */ 1682 1683 /* checksum functions */ 1684 1685 /* 1686 These functions are not related to compression but are exported 1687 anyway because they might be useful in applications using the compression 1688 library. 1689 */ 1690 1691 ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len)); 1692 /* 1693 Update a running Adler-32 checksum with the bytes buf[0..len-1] and 1694 return the updated checksum. An Adler-32 value is in the range of a 32-bit 1695 unsigned integer. If buf is Z_NULL, this function returns the required 1696 initial value for the checksum. 1697 1698 An Adler-32 checksum is almost as reliable as a CRC-32 but can be computed 1699 much faster. 1700 1701 Usage example: 1702 1703 uLong adler = adler32(0L, Z_NULL, 0); 1704 1705 while (read_buffer(buffer, length) != EOF) { 1706 adler = adler32(adler, buffer, length); 1707 } 1708 if (adler != original_adler) error(); 1709 */ 1710 1711 ZEXTERN uLong ZEXPORT adler32_z OF((uLong adler, const Bytef *buf, 1712 z_size_t len)); 1713 /* 1714 Same as adler32(), but with a size_t length. 1715 */ 1716 1717 /* 1718 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong adler1, uLong adler2, 1719 z_off_t len2)); 1720 1721 Combine two Adler-32 checksums into one. For two sequences of bytes, seq1 1722 and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for 1723 each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of 1724 seq1 and seq2 concatenated, requiring only adler1, adler2, and len2. Note 1725 that the z_off_t type (like off_t) is a signed integer. If len2 is 1726 negative, the result has no meaning or utility. 1727 */ 1728 1729 ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len)); 1730 /* 1731 Update a running CRC-32 with the bytes buf[0..len-1] and return the 1732 updated CRC-32. A CRC-32 value is in the range of a 32-bit unsigned integer. 1733 If buf is Z_NULL, this function returns the required initial value for the 1734 crc. Pre- and post-conditioning (one's complement) is performed within this 1735 function so it shouldn't be done by the application. 1736 1737 Usage example: 1738 1739 uLong crc = crc32(0L, Z_NULL, 0); 1740 1741 while (read_buffer(buffer, length) != EOF) { 1742 crc = crc32(crc, buffer, length); 1743 } 1744 if (crc != original_crc) error(); 1745 */ 1746 1747 ZEXTERN uLong ZEXPORT crc32_z OF((uLong crc, const Bytef *buf, 1748 z_size_t len)); 1749 /* 1750 Same as crc32(), but with a size_t length. 1751 */ 1752 1753 /* 1754 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2)); 1755 1756 Combine two CRC-32 check values into one. For two sequences of bytes, 1757 seq1 and seq2 with lengths len1 and len2, CRC-32 check values were 1758 calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32 1759 check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and 1760 len2. 1761 */ 1762 1763 /* 1764 ZEXTERN uLong ZEXPORT crc32_combine_gen OF((z_off_t len2)); 1765 1766 Return the operator corresponding to length len2, to be used with 1767 crc32_combine_op(). 1768 */ 1769 1770 ZEXTERN uLong ZEXPORT crc32_combine_op OF((uLong crc1, uLong crc2, uLong op)); 1771 /* 1772 Give the same result as crc32_combine(), using op in place of len2. op is 1773 is generated from len2 by crc32_combine_gen(). This will be faster than 1774 crc32_combine() if the generated op is used more than once. 1775 */ 1776 1777 1778 /* various hacks, don't look :) */ 1779 1780 /* deflateInit and inflateInit are macros to allow checking the zlib version 1781 * and the compiler's view of z_stream: 1782 */ 1783 ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level, 1784 const char *version, int stream_size)); 1785 ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm, 1786 const char *version, int stream_size)); 1787 ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method, 1788 int windowBits, int memLevel, 1789 int strategy, const char *version, 1790 int stream_size)); 1791 ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits, 1792 const char *version, int stream_size)); 1793 ZEXTERN int ZEXPORT inflateBackInit_ OF((z_streamp strm, int windowBits, 1794 unsigned char FAR *window, 1795 const char *version, 1796 int stream_size)); 1797 #ifdef Z_PREFIX_SET 1798 # define z_deflateInit(strm, level) \ 1799 deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream)) 1800 # define z_inflateInit(strm) \ 1801 inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream)) 1802 # define z_deflateInit2(strm, level, method, windowBits, memLevel, strategy) \ 1803 deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\ 1804 (strategy), ZLIB_VERSION, (int)sizeof(z_stream)) 1805 # define z_inflateInit2(strm, windowBits) \ 1806 inflateInit2_((strm), (windowBits), ZLIB_VERSION, \ 1807 (int)sizeof(z_stream)) 1808 # define z_inflateBackInit(strm, windowBits, window) \ 1809 inflateBackInit_((strm), (windowBits), (window), \ 1810 ZLIB_VERSION, (int)sizeof(z_stream)) 1811 #else 1812 # define deflateInit(strm, level) \ 1813 deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream)) 1814 # define inflateInit(strm) \ 1815 inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream)) 1816 # define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \ 1817 deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\ 1818 (strategy), ZLIB_VERSION, (int)sizeof(z_stream)) 1819 # define inflateInit2(strm, windowBits) \ 1820 inflateInit2_((strm), (windowBits), ZLIB_VERSION, \ 1821 (int)sizeof(z_stream)) 1822 # define inflateBackInit(strm, windowBits, window) \ 1823 inflateBackInit_((strm), (windowBits), (window), \ 1824 ZLIB_VERSION, (int)sizeof(z_stream)) 1825 #endif 1826 1827 #ifndef Z_SOLO 1828 1829 /* gzgetc() macro and its supporting function and exposed data structure. Note 1830 * that the real internal state is much larger than the exposed structure. 1831 * This abbreviated structure exposes just enough for the gzgetc() macro. The 1832 * user should not mess with these exposed elements, since their names or 1833 * behavior could change in the future, perhaps even capriciously. They can 1834 * only be used by the gzgetc() macro. You have been warned. 1835 */ 1836 struct gzFile_s { 1837 unsigned have; 1838 unsigned char *next; 1839 z_off64_t pos; 1840 }; 1841 ZEXTERN int ZEXPORT gzgetc_ OF((gzFile file)); /* backward compatibility */ 1842 #ifdef Z_PREFIX_SET 1843 # undef z_gzgetc 1844 # define z_gzgetc(g) \ 1845 ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : (gzgetc)(g)) 1846 #else 1847 # define gzgetc(g) \ 1848 ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : (gzgetc)(g)) 1849 #endif 1850 1851 /* provide 64-bit offset functions if _LARGEFILE64_SOURCE defined, and/or 1852 * change the regular functions to 64 bits if _FILE_OFFSET_BITS is 64 (if 1853 * both are true, the application gets the *64 functions, and the regular 1854 * functions are changed to 64 bits) -- in case these are set on systems 1855 * without large file support, _LFS64_LARGEFILE must also be true 1856 */ 1857 #ifdef Z_LARGE64 1858 ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *)); 1859 ZEXTERN z_off64_t ZEXPORT gzseek64 OF((gzFile, z_off64_t, int)); 1860 ZEXTERN z_off64_t ZEXPORT gztell64 OF((gzFile)); 1861 ZEXTERN z_off64_t ZEXPORT gzoffset64 OF((gzFile)); 1862 ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off64_t)); 1863 ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off64_t)); 1864 ZEXTERN uLong ZEXPORT crc32_combine_gen64 OF((z_off64_t)); 1865 #endif 1866 1867 #if !defined(ZLIB_INTERNAL) && defined(Z_WANT64) 1868 # ifdef Z_PREFIX_SET 1869 # define z_gzopen z_gzopen64 1870 # define z_gzseek z_gzseek64 1871 # define z_gztell z_gztell64 1872 # define z_gzoffset z_gzoffset64 1873 # define z_adler32_combine z_adler32_combine64 1874 # define z_crc32_combine z_crc32_combine64 1875 # define z_crc32_combine_gen z_crc32_combine_gen64 1876 # else 1877 # define gzopen gzopen64 1878 # define gzseek gzseek64 1879 # define gztell gztell64 1880 # define gzoffset gzoffset64 1881 # define adler32_combine adler32_combine64 1882 # define crc32_combine crc32_combine64 1883 # define crc32_combine_gen crc32_combine_gen64 1884 # endif 1885 # ifndef Z_LARGE64 1886 ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *)); 1887 ZEXTERN z_off_t ZEXPORT gzseek64 OF((gzFile, z_off_t, int)); 1888 ZEXTERN z_off_t ZEXPORT gztell64 OF((gzFile)); 1889 ZEXTERN z_off_t ZEXPORT gzoffset64 OF((gzFile)); 1890 ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off_t)); 1891 ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off_t)); 1892 ZEXTERN uLong ZEXPORT crc32_combine_gen64 OF((z_off_t)); 1893 # endif 1894 #else 1895 ZEXTERN gzFile ZEXPORT gzopen OF((const char *, const char *)); 1896 ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile, z_off_t, int)); 1897 ZEXTERN z_off_t ZEXPORT gztell OF((gzFile)); 1898 ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile)); 1899 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t)); 1900 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t)); 1901 ZEXTERN uLong ZEXPORT crc32_combine_gen OF((z_off_t)); 1902 #endif 1903 1904 #else /* Z_SOLO */ 1905 1906 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t)); 1907 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t)); 1908 ZEXTERN uLong ZEXPORT crc32_combine_gen OF((z_off_t)); 1909 1910 #endif /* !Z_SOLO */ 1911 1912 /* undocumented functions */ 1913 ZEXTERN const char * ZEXPORT zError OF((int)); 1914 ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp)); 1915 ZEXTERN const z_crc_t FAR * ZEXPORT get_crc_table OF((void)); 1916 ZEXTERN int ZEXPORT inflateUndermine OF((z_streamp, int)); 1917 ZEXTERN int ZEXPORT inflateValidate OF((z_streamp, int)); 1918 ZEXTERN unsigned long ZEXPORT inflateCodesUsed OF((z_streamp)); 1919 ZEXTERN int ZEXPORT inflateResetKeep OF((z_streamp)); 1920 ZEXTERN int ZEXPORT deflateResetKeep OF((z_streamp)); 1921 #if defined(_WIN32) && !defined(Z_SOLO) 1922 ZEXTERN gzFile ZEXPORT gzopen_w OF((const wchar_t *path, 1923 const char *mode)); 1924 #endif 1925 #if defined(STDC) || defined(Z_HAVE_STDARG_H) 1926 # ifndef Z_SOLO 1927 ZEXTERN int ZEXPORTVA gzvprintf Z_ARG((gzFile file, 1928 const char *format, 1929 va_list va)); 1930 # endif 1931 #endif 1932 1933 #ifdef __cplusplus 1934 } 1935 #endif 1936 1937 #endif /* ZLIB_H */ 1938
Indexes created Wed Sep 24 05:09:52 GMT 2025