1 /* SPDX-License-Identifier: Zlib */ 2 /* zlib.h -- interface of the 'zlib' general purpose compression library 3 version 1.2.12, March 11th, 2022 4 5 Copyright (C) 1995-2022 Jean-loup Gailly and Mark Adler 6 7 This software is provided 'as-is', without any express or implied 8 warranty. In no event will the authors be held liable for any damages 9 arising from the use of this software. 10 11 Permission is granted to anyone to use this software for any purpose, 12 including commercial applications, and to alter it and redistribute it 13 freely, subject to the following restrictions: 14 15 1. The origin of this software must not be misrepresented; you must not 16 claim that you wrote the original software. If you use this software 17 in a product, an acknowledgment in the product documentation would be 18 appreciated but is not required. 19 2. Altered source versions must be plainly marked as such, and must not be 20 misrepresented as being the original software. 21 3. This notice may not be removed or altered from any source distribution. 22 23 Jean-loup Gailly Mark Adler 24 jloup@gzip.org madler@alumni.caltech.edu 25 26 27 The data format used by the zlib library is described by RFCs (Request for 28 Comments) 1950 to 1952 in the files http://tools.ietf.org/html/rfc1950 29 (zlib format), rfc1951 (deflate format) and rfc1952 (gzip format). 30 */ 31 32 #ifndef ZLIB_H 33 #define ZLIB_H 34 35 #include "zconf.h" 36 37 #ifdef __cplusplus 38 extern "C" { 39 #endif 40 41 #define ZLIB_VERSION "1.2.12" 42 #define ZLIB_VERNUM 0x12c0 43 #define ZLIB_VER_MAJOR 1 44 #define ZLIB_VER_MINOR 2 45 #define ZLIB_VER_REVISION 12 46 #define ZLIB_VER_SUBREVISION 0 47 48 /* 49 The 'zlib' compression library provides in-memory compression and 50 decompression functions, including integrity checks of the uncompressed data. 51 This version of the library supports only one compression method (deflation) 52 but other algorithms will be added later and will have the same stream 53 interface. 54 55 Compression can be done in a single step if the buffers are large enough, 56 or can be done by repeated calls of the compression function. In the latter 57 case, the application must provide more input and/or consume the output 58 (providing more output space) before each call. 59 60 The compressed data format used by default by the in-memory functions is 61 the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped 62 around a deflate stream, which is itself documented in RFC 1951. 63 64 The library also supports reading and writing files in gzip (.gz) format 65 with an interface similar to that of stdio using the functions that start 66 with "gz". The gzip format is different from the zlib format. gzip is a 67 gzip wrapper, documented in RFC 1952, wrapped around a deflate stream. 68 69 This library can optionally read and write gzip and raw deflate streams in 70 memory as well. 71 72 The zlib format was designed to be compact and fast for use in memory 73 and on communications channels. The gzip format was designed for single- 74 file compression on file systems, has a larger header than zlib to maintain 75 directory information, and uses a different, slower check method than zlib. 76 77 The library does not install any signal handler. The decoder checks 78 the consistency of the compressed data, so the library should never crash 79 even in the case of corrupted input. 80 */ 81 82 typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size)); 83 typedef void (*free_func) OF((voidpf opaque, voidpf address)); 84 85 struct internal_state; 86 87 typedef struct z_stream_s { 88 z_const Bytef *next_in; /* next input byte */ 89 uInt avail_in; /* number of bytes available at next_in */ 90 uLong total_in; /* total number of input bytes read so far */ 91 92 Bytef *next_out; /* next output byte will go here */ 93 uInt avail_out; /* remaining free space at next_out */ 94 uLong total_out; /* total number of bytes output so far */ 95 96 z_const char *msg; /* last error message, NULL if no error */ 97 struct internal_state FAR *state; /* not visible by applications */ 98 99 alloc_func zalloc; /* used to allocate the internal state */ 100 free_func zfree; /* used to free the internal state */ 101 voidpf opaque; /* private data object passed to zalloc and zfree */ 102 103 int data_type; /* best guess about the data type: binary or text 104 for deflate, or the decoding state for inflate */ 105 uLong adler; /* Adler-32 or CRC-32 value of the uncompressed data */ 106 uLong reserved; /* reserved for future use */ 107 } z_stream; 108 109 typedef z_stream FAR *z_streamp; 110 111 /* 112 gzip header information passed to and from zlib routines. See RFC 1952 113 for more details on the meanings of these fields. 114 */ 115 typedef struct gz_header_s { 116 int text; /* true if compressed data believed to be text */ 117 uLong time; /* modification time */ 118 int xflags; /* extra flags (not used when writing a gzip file) */ 119 int os; /* operating system */ 120 Bytef *extra; /* pointer to extra field or Z_NULL if none */ 121 uInt extra_len; /* extra field length (valid if extra != Z_NULL) */ 122 uInt extra_max; /* space at extra (only when reading header) */ 123 Bytef *name; /* pointer to zero-terminated file name or Z_NULL */ 124 uInt name_max; /* space at name (only when reading header) */ 125 Bytef *comment; /* pointer to zero-terminated comment or Z_NULL */ 126 uInt comm_max; /* space at comment (only when reading header) */ 127 int hcrc; /* true if there was or will be a header crc */ 128 int done; /* true when done reading gzip header (not used 129 when writing a gzip file) */ 130 } gz_header; 131 132 typedef gz_header FAR *gz_headerp; 133 134 /* 135 The application must update next_in and avail_in when avail_in has dropped 136 to zero. It must update next_out and avail_out when avail_out has dropped 137 to zero. The application must initialize zalloc, zfree and opaque before 138 calling the init function. All other fields are set by the compression 139 library and must not be updated by the application. 140 141 The opaque value provided by the application will be passed as the first 142 parameter for calls of zalloc and zfree. This can be useful for custom 143 memory management. The compression library attaches no meaning to the 144 opaque value. 145 146 zalloc must return Z_NULL if there is not enough memory for the object. 147 If zlib is used in a multi-threaded application, zalloc and zfree must be 148 thread safe. In that case, zlib is thread-safe. When zalloc and zfree are 149 Z_NULL on entry to the initialization function, they are set to internal 150 routines that use the standard library functions malloc() and free(). 151 152 On 16-bit systems, the functions zalloc and zfree must be able to allocate 153 exactly 65536 bytes, but will not be required to allocate more than this if 154 the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, pointers 155 returned by zalloc for objects of exactly 65536 bytes *must* have their 156 offset normalized to zero. The default allocation function provided by this 157 library ensures this (see zutil.c). To reduce memory requirements and avoid 158 any allocation of 64K objects, at the expense of compression ratio, compile 159 the library with -DMAX_WBITS=14 (see zconf.h). 160 161 The fields total_in and total_out can be used for statistics or progress 162 reports. After compression, total_in holds the total size of the 163 uncompressed data and may be saved for use by the decompressor (particularly 164 if the decompressor wants to decompress everything in a single step). 165 */ 166 167 /* constants */ 168 169 #define Z_NO_FLUSH 0 170 #define Z_PARTIAL_FLUSH 1 171 #define Z_SYNC_FLUSH 2 172 #define Z_FULL_FLUSH 3 173 #define Z_FINISH 4 174 #define Z_BLOCK 5 175 #define Z_TREES 6 176 /* Allowed flush values; see deflate() and inflate() below for details */ 177 178 #define Z_OK 0 179 #define Z_STREAM_END 1 180 #define Z_NEED_DICT 2 181 #define Z_ERRNO (-1) 182 #define Z_STREAM_ERROR (-2) 183 #define Z_DATA_ERROR (-3) 184 #define Z_MEM_ERROR (-4) 185 #define Z_BUF_ERROR (-5) 186 #define Z_VERSION_ERROR (-6) 187 /* Return codes for the compression/decompression functions. Negative values 188 * are errors, positive values are used for special but normal events. 189 */ 190 191 #define Z_NO_COMPRESSION 0 192 #define Z_BEST_SPEED 1 193 #define Z_BEST_COMPRESSION 9 194 #define Z_DEFAULT_COMPRESSION (-1) 195 /* compression levels */ 196 197 #define Z_FILTERED 1 198 #define Z_HUFFMAN_ONLY 2 199 #define Z_RLE 3 200 #define Z_FIXED 4 201 #define Z_DEFAULT_STRATEGY 0 202 /* compression strategy; see deflateInit2() below for details */ 203 204 #define Z_BINARY 0 205 #define Z_TEXT 1 206 #define Z_ASCII Z_TEXT /* for compatibility with 1.2.2 and earlier */ 207 #define Z_UNKNOWN 2 208 /* Possible values of the data_type field for deflate() */ 209 210 #define Z_DEFLATED 8 211 /* The deflate compression method (the only one supported in this version) */ 212 213 #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */ 214 215 #define zlib_version zlibVersion() 216 /* for compatibility with versions < 1.0.2 */ 217 218 219 /* basic functions */ 220 221 ZEXTERN const char * ZEXPORT zlibVersion OF((void)); 222 /* The application can compare zlibVersion and ZLIB_VERSION for consistency. 223 If the first character differs, the library code actually used is not 224 compatible with the zlib.h header file used by the application. This check 225 is automatically made by deflateInit and inflateInit. 226 */ 227 228 /* 229 ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level)); 230 231 Initializes the internal stream state for compression. The fields 232 zalloc, zfree and opaque must be initialized before by the caller. If 233 zalloc and zfree are set to Z_NULL, deflateInit updates them to use default 234 allocation functions. 235 236 The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9: 237 1 gives best speed, 9 gives best compression, 0 gives no compression at all 238 (the input data is simply copied a block at a time). Z_DEFAULT_COMPRESSION 239 requests a default compromise between speed and compression (currently 240 equivalent to level 6). 241 242 deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough 243 memory, Z_STREAM_ERROR if level is not a valid compression level, or 244 Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible 245 with the version assumed by the caller (ZLIB_VERSION). msg is set to null 246 if there is no error message. deflateInit does not perform any compression: 247 this will be done by deflate(). 248 */ 249 250 251 ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush)); 252 /* 253 deflate compresses as much data as possible, and stops when the input 254 buffer becomes empty or the output buffer becomes full. It may introduce 255 some output latency (reading input without producing any output) except when 256 forced to flush. 257 258 The detailed semantics are as follows. deflate performs one or both of the 259 following actions: 260 261 - Compress more input starting at next_in and update next_in and avail_in 262 accordingly. If not all input can be processed (because there is not 263 enough room in the output buffer), next_in and avail_in are updated and 264 processing will resume at this point for the next call of deflate(). 265 266 - Generate more output starting at next_out and update next_out and avail_out 267 accordingly. This action is forced if the parameter flush is non zero. 268 Forcing flush frequently degrades the compression ratio, so this parameter 269 should be set only when necessary. Some output may be provided even if 270 flush is zero. 271 272 Before the call of deflate(), the application should ensure that at least 273 one of the actions is possible, by providing more input and/or consuming more 274 output, and updating avail_in or avail_out accordingly; avail_out should 275 never be zero before the call. The application can consume the compressed 276 output when it wants, for example when the output buffer is full (avail_out 277 == 0), or after each call of deflate(). If deflate returns Z_OK and with 278 zero avail_out, it must be called again after making room in the output 279 buffer because there might be more output pending. See deflatePending(), 280 which can be used if desired to determine whether or not there is more ouput 281 in that case. 282 283 Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to 284 decide how much data to accumulate before producing output, in order to 285 maximize compression. 286 287 If the parameter flush is set to Z_SYNC_FLUSH, all pending output is 288 flushed to the output buffer and the output is aligned on a byte boundary, so 289 that the decompressor can get all input data available so far. (In 290 particular avail_in is zero after the call if enough output space has been 291 provided before the call.) Flushing may degrade compression for some 292 compression algorithms and so it should be used only when necessary. This 293 completes the current deflate block and follows it with an empty stored block 294 that is three bits plus filler bits to the next byte, followed by four bytes 295 (00 00 ff ff). 296 297 If flush is set to Z_PARTIAL_FLUSH, all pending output is flushed to the 298 output buffer, but the output is not aligned to a byte boundary. All of the 299 input data so far will be available to the decompressor, as for Z_SYNC_FLUSH. 300 This completes the current deflate block and follows it with an empty fixed 301 codes block that is 10 bits long. This assures that enough bytes are output 302 in order for the decompressor to finish the block before the empty fixed 303 codes block. 304 305 If flush is set to Z_BLOCK, a deflate block is completed and emitted, as 306 for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to 307 seven bits of the current block are held to be written as the next byte after 308 the next deflate block is completed. In this case, the decompressor may not 309 be provided enough bits at this point in order to complete decompression of 310 the data provided so far to the compressor. It may need to wait for the next 311 block to be emitted. This is for advanced applications that need to control 312 the emission of deflate blocks. 313 314 If flush is set to Z_FULL_FLUSH, all output is flushed as with 315 Z_SYNC_FLUSH, and the compression state is reset so that decompression can 316 restart from this point if previous compressed data has been damaged or if 317 random access is desired. Using Z_FULL_FLUSH too often can seriously degrade 318 compression. 319 320 If deflate returns with avail_out == 0, this function must be called again 321 with the same value of the flush parameter and more output space (updated 322 avail_out), until the flush is complete (deflate returns with non-zero 323 avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that 324 avail_out is greater than six to avoid repeated flush markers due to 325 avail_out == 0 on return. 326 327 If the parameter flush is set to Z_FINISH, pending input is processed, 328 pending output is flushed and deflate returns with Z_STREAM_END if there was 329 enough output space. If deflate returns with Z_OK or Z_BUF_ERROR, this 330 function must be called again with Z_FINISH and more output space (updated 331 avail_out) but no more input data, until it returns with Z_STREAM_END or an 332 error. After deflate has returned Z_STREAM_END, the only possible operations 333 on the stream are deflateReset or deflateEnd. 334 335 Z_FINISH can be used in the first deflate call after deflateInit if all the 336 compression is to be done in a single step. In order to complete in one 337 call, avail_out must be at least the value returned by deflateBound (see 338 below). Then deflate is guaranteed to return Z_STREAM_END. If not enough 339 output space is provided, deflate will not return Z_STREAM_END, and it must 340 be called again as described above. 341 342 deflate() sets strm->adler to the Adler-32 checksum of all input read 343 so far (that is, total_in bytes). If a gzip stream is being generated, then 344 strm->adler will be the CRC-32 checksum of the input read so far. (See 345 deflateInit2 below.) 346 347 deflate() may update strm->data_type if it can make a good guess about 348 the input data type (Z_BINARY or Z_TEXT). If in doubt, the data is 349 considered binary. This field is only for information purposes and does not 350 affect the compression algorithm in any manner. 351 352 deflate() returns Z_OK if some progress has been made (more input 353 processed or more output produced), Z_STREAM_END if all input has been 354 consumed and all output has been produced (only when flush is set to 355 Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example 356 if next_in or next_out was Z_NULL or the state was inadvertently written over 357 by the application), or Z_BUF_ERROR if no progress is possible (for example 358 avail_in or avail_out was zero). Note that Z_BUF_ERROR is not fatal, and 359 deflate() can be called again with more input and more output space to 360 continue compressing. 361 */ 362 363 364 ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm)); 365 /* 366 All dynamically allocated data structures for this stream are freed. 367 This function discards any unprocessed input and does not flush any pending 368 output. 369 370 deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the 371 stream state was inconsistent, Z_DATA_ERROR if the stream was freed 372 prematurely (some input or output was discarded). In the error case, msg 373 may be set but then points to a static string (which must not be 374 deallocated). 375 */ 376 377 378 /* 379 ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm)); 380 381 Initializes the internal stream state for decompression. The fields 382 next_in, avail_in, zalloc, zfree and opaque must be initialized before by 383 the caller. In the current version of inflate, the provided input is not 384 read or consumed. The allocation of a sliding window will be deferred to 385 the first call of inflate (if the decompression does not complete on the 386 first call). If zalloc and zfree are set to Z_NULL, inflateInit updates 387 them to use default allocation functions. 388 389 inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough 390 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the 391 version assumed by the caller, or Z_STREAM_ERROR if the parameters are 392 invalid, such as a null pointer to the structure. msg is set to null if 393 there is no error message. inflateInit does not perform any decompression. 394 Actual decompression will be done by inflate(). So next_in, and avail_in, 395 next_out, and avail_out are unused and unchanged. The current 396 implementation of inflateInit() does not process any header information -- 397 that is deferred until inflate() is called. 398 */ 399 400 401 ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush)); 402 /* 403 inflate decompresses as much data as possible, and stops when the input 404 buffer becomes empty or the output buffer becomes full. It may introduce 405 some output latency (reading input without producing any output) except when 406 forced to flush. 407 408 The detailed semantics are as follows. inflate performs one or both of the 409 following actions: 410 411 - Decompress more input starting at next_in and update next_in and avail_in 412 accordingly. If not all input can be processed (because there is not 413 enough room in the output buffer), then next_in and avail_in are updated 414 accordingly, and processing will resume at this point for the next call of 415 inflate(). 416 417 - Generate more output starting at next_out and update next_out and avail_out 418 accordingly. inflate() provides as much output as possible, until there is 419 no more input data or no more space in the output buffer (see below about 420 the flush parameter). 421 422 Before the call of inflate(), the application should ensure that at least 423 one of the actions is possible, by providing more input and/or consuming more 424 output, and updating the next_* and avail_* values accordingly. If the 425 caller of inflate() does not provide both available input and available 426 output space, it is possible that there will be no progress made. The 427 application can consume the uncompressed output when it wants, for example 428 when the output buffer is full (avail_out == 0), or after each call of 429 inflate(). If inflate returns Z_OK and with zero avail_out, it must be 430 called again after making room in the output buffer because there might be 431 more output pending. 432 433 The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, Z_FINISH, 434 Z_BLOCK, or Z_TREES. Z_SYNC_FLUSH requests that inflate() flush as much 435 output as possible to the output buffer. Z_BLOCK requests that inflate() 436 stop if and when it gets to the next deflate block boundary. When decoding 437 the zlib or gzip format, this will cause inflate() to return immediately 438 after the header and before the first block. When doing a raw inflate, 439 inflate() will go ahead and process the first block, and will return when it 440 gets to the end of that block, or when it runs out of data. 441 442 The Z_BLOCK option assists in appending to or combining deflate streams. 443 To assist in this, on return inflate() always sets strm->data_type to the 444 number of unused bits in the last byte taken from strm->next_in, plus 64 if 445 inflate() is currently decoding the last block in the deflate stream, plus 446 128 if inflate() returned immediately after decoding an end-of-block code or 447 decoding the complete header up to just before the first byte of the deflate 448 stream. The end-of-block will not be indicated until all of the uncompressed 449 data from that block has been written to strm->next_out. The number of 450 unused bits may in general be greater than seven, except when bit 7 of 451 data_type is set, in which case the number of unused bits will be less than 452 eight. data_type is set as noted here every time inflate() returns for all 453 flush options, and so can be used to determine the amount of currently 454 consumed input in bits. 455 456 The Z_TREES option behaves as Z_BLOCK does, but it also returns when the 457 end of each deflate block header is reached, before any actual data in that 458 block is decoded. This allows the caller to determine the length of the 459 deflate block header for later use in random access within a deflate block. 460 256 is added to the value of strm->data_type when inflate() returns 461 immediately after reaching the end of the deflate block header. 462 463 inflate() should normally be called until it returns Z_STREAM_END or an 464 error. However if all decompression is to be performed in a single step (a 465 single call of inflate), the parameter flush should be set to Z_FINISH. In 466 this case all pending input is processed and all pending output is flushed; 467 avail_out must be large enough to hold all of the uncompressed data for the 468 operation to complete. (The size of the uncompressed data may have been 469 saved by the compressor for this purpose.) The use of Z_FINISH is not 470 required to perform an inflation in one step. However it may be used to 471 inform inflate that a faster approach can be used for the single inflate() 472 call. Z_FINISH also informs inflate to not maintain a sliding window if the 473 stream completes, which reduces inflate's memory footprint. If the stream 474 does not complete, either because not all of the stream is provided or not 475 enough output space is provided, then a sliding window will be allocated and 476 inflate() can be called again to continue the operation as if Z_NO_FLUSH had 477 been used. 478 479 In this implementation, inflate() always flushes as much output as 480 possible to the output buffer, and always uses the faster approach on the 481 first call. So the effects of the flush parameter in this implementation are 482 on the return value of inflate() as noted below, when inflate() returns early 483 when Z_BLOCK or Z_TREES is used, and when inflate() avoids the allocation of 484 memory for a sliding window when Z_FINISH is used. 485 486 If a preset dictionary is needed after this call (see inflateSetDictionary 487 below), inflate sets strm->adler to the Adler-32 checksum of the dictionary 488 chosen by the compressor and returns Z_NEED_DICT; otherwise it sets 489 strm->adler to the Adler-32 checksum of all output produced so far (that is, 490 total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described 491 below. At the end of the stream, inflate() checks that its computed Adler-32 492 checksum is equal to that saved by the compressor and returns Z_STREAM_END 493 only if the checksum is correct. 494 495 inflate() can decompress and check either zlib-wrapped or gzip-wrapped 496 deflate data. The header type is detected automatically, if requested when 497 initializing with inflateInit2(). Any information contained in the gzip 498 header is not retained unless inflateGetHeader() is used. When processing 499 gzip-wrapped deflate data, strm->adler32 is set to the CRC-32 of the output 500 produced so far. The CRC-32 is checked against the gzip trailer, as is the 501 uncompressed length, modulo 2^32. 502 503 inflate() returns Z_OK if some progress has been made (more input processed 504 or more output produced), Z_STREAM_END if the end of the compressed data has 505 been reached and all uncompressed output has been produced, Z_NEED_DICT if a 506 preset dictionary is needed at this point, Z_DATA_ERROR if the input data was 507 corrupted (input stream not conforming to the zlib format or incorrect check 508 value, in which case strm->msg points to a string with a more specific 509 error), Z_STREAM_ERROR if the stream structure was inconsistent (for example 510 next_in or next_out was Z_NULL, or the state was inadvertently written over 511 by the application), Z_MEM_ERROR if there was not enough memory, Z_BUF_ERROR 512 if no progress was possible or if there was not enough room in the output 513 buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and 514 inflate() can be called again with more input and more output space to 515 continue decompressing. If Z_DATA_ERROR is returned, the application may 516 then call inflateSync() to look for a good compression block if a partial 517 recovery of the data is to be attempted. 518 */ 519 520 521 ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm)); 522 /* 523 All dynamically allocated data structures for this stream are freed. 524 This function discards any unprocessed input and does not flush any pending 525 output. 526 527 inflateEnd returns Z_OK if success, or Z_STREAM_ERROR if the stream state 528 was inconsistent. 529 */ 530 531 532 /* Advanced functions */ 533 534 /* 535 The following functions are needed only in some special applications. 536 */ 537 538 /* 539 ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm, 540 int level, 541 int method, 542 int windowBits, 543 int memLevel, 544 int strategy)); 545 546 This is another version of deflateInit with more compression options. The 547 fields zalloc, zfree and opaque must be initialized before by the caller. 548 549 The method parameter is the compression method. It must be Z_DEFLATED in 550 this version of the library. 551 552 The windowBits parameter is the base two logarithm of the window size 553 (the size of the history buffer). It should be in the range 8..15 for this 554 version of the library. Larger values of this parameter result in better 555 compression at the expense of memory usage. The default value is 15 if 556 deflateInit is used instead. 557 558 For the current implementation of deflate(), a windowBits value of 8 (a 559 window size of 256 bytes) is not supported. As a result, a request for 8 560 will result in 9 (a 512-byte window). In that case, providing 8 to 561 inflateInit2() will result in an error when the zlib header with 9 is 562 checked against the initialization of inflate(). The remedy is to not use 8 563 with deflateInit2() with this initialization, or at least in that case use 9 564 with inflateInit2(). 565 566 windowBits can also be -8..-15 for raw deflate. In this case, -windowBits 567 determines the window size. deflate() will then generate raw deflate data 568 with no zlib header or trailer, and will not compute a check value. 569 570 windowBits can also be greater than 15 for optional gzip encoding. Add 571 16 to windowBits to write a simple gzip header and trailer around the 572 compressed data instead of a zlib wrapper. The gzip header will have no 573 file name, no extra data, no comment, no modification time (set to zero), no 574 header crc, and the operating system will be set to the appropriate value, 575 if the operating system was determined at compile time. If a gzip stream is 576 being written, strm->adler is a CRC-32 instead of an Adler-32. 577 578 For raw deflate or gzip encoding, a request for a 256-byte window is 579 rejected as invalid, since only the zlib header provides a means of 580 transmitting the window size to the decompressor. 581 582 The memLevel parameter specifies how much memory should be allocated 583 for the internal compression state. memLevel=1 uses minimum memory but is 584 slow and reduces compression ratio; memLevel=9 uses maximum memory for 585 optimal speed. The default value is 8. See zconf.h for total memory usage 586 as a function of windowBits and memLevel. 587 588 The strategy parameter is used to tune the compression algorithm. Use the 589 value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a 590 filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no 591 string match), or Z_RLE to limit match distances to one (run-length 592 encoding). Filtered data consists mostly of small values with a somewhat 593 random distribution. In this case, the compression algorithm is tuned to 594 compress them better. The effect of Z_FILTERED is to force more Huffman 595 coding and less string matching; it is somewhat intermediate between 596 Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as 597 fast as Z_HUFFMAN_ONLY, but give better compression for PNG image data. The 598 strategy parameter only affects the compression ratio but not the 599 correctness of the compressed output even if it is not set appropriately. 600 Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler 601 decoder for special applications. 602 603 deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 604 memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid 605 method), or Z_VERSION_ERROR if the zlib library version (zlib_version) is 606 incompatible with the version assumed by the caller (ZLIB_VERSION). msg is 607 set to null if there is no error message. deflateInit2 does not perform any 608 compression: this will be done by deflate(). 609 */ 610 611 ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm, 612 const Bytef *dictionary, 613 uInt dictLength)); 614 /* 615 Initializes the compression dictionary from the given byte sequence 616 without producing any compressed output. When using the zlib format, this 617 function must be called immediately after deflateInit, deflateInit2 or 618 deflateReset, and before any call of deflate. When doing raw deflate, this 619 function must be called either before any call of deflate, or immediately 620 after the completion of a deflate block, i.e. after all input has been 621 consumed and all output has been delivered when using any of the flush 622 options Z_BLOCK, Z_PARTIAL_FLUSH, Z_SYNC_FLUSH, or Z_FULL_FLUSH. The 623 compressor and decompressor must use exactly the same dictionary (see 624 inflateSetDictionary). 625 626 The dictionary should consist of strings (byte sequences) that are likely 627 to be encountered later in the data to be compressed, with the most commonly 628 used strings preferably put towards the end of the dictionary. Using a 629 dictionary is most useful when the data to be compressed is short and can be 630 predicted with good accuracy; the data can then be compressed better than 631 with the default empty dictionary. 632 633 Depending on the size of the compression data structures selected by 634 deflateInit or deflateInit2, a part of the dictionary may in effect be 635 discarded, for example if the dictionary is larger than the window size 636 provided in deflateInit or deflateInit2. Thus the strings most likely to be 637 useful should be put at the end of the dictionary, not at the front. In 638 addition, the current implementation of deflate will use at most the window 639 size minus 262 bytes of the provided dictionary. 640 641 Upon return of this function, strm->adler is set to the Adler-32 value 642 of the dictionary; the decompressor may later use this value to determine 643 which dictionary has been used by the compressor. (The Adler-32 value 644 applies to the whole dictionary even if only a subset of the dictionary is 645 actually used by the compressor.) If a raw deflate was requested, then the 646 Adler-32 value is not computed and strm->adler is not set. 647 648 deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a 649 parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is 650 inconsistent (for example if deflate has already been called for this stream 651 or if not at a block boundary for raw deflate). deflateSetDictionary does 652 not perform any compression: this will be done by deflate(). 653 */ 654 655 ZEXTERN int ZEXPORT deflateGetDictionary OF((z_streamp strm, 656 Bytef *dictionary, 657 uInt *dictLength)); 658 /* 659 Returns the sliding dictionary being maintained by deflate. dictLength is 660 set to the number of bytes in the dictionary, and that many bytes are copied 661 to dictionary. dictionary must have enough space, where 32768 bytes is 662 always enough. If deflateGetDictionary() is called with dictionary equal to 663 Z_NULL, then only the dictionary length is returned, and nothing is copied. 664 Similary, if dictLength is Z_NULL, then it is not set. 665 666 deflateGetDictionary() may return a length less than the window size, even 667 when more than the window size in input has been provided. It may return up 668 to 258 bytes less in that case, due to how zlib's implementation of deflate 669 manages the sliding window and lookahead for matches, where matches can be 670 up to 258 bytes long. If the application needs the last window-size bytes of 671 input, then that would need to be saved by the application outside of zlib. 672 673 deflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the 674 stream state is inconsistent. 675 */ 676 677 ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest, 678 z_streamp source)); 679 /* 680 Sets the destination stream as a complete copy of the source stream. 681 682 This function can be useful when several compression strategies will be 683 tried, for example when there are several ways of pre-processing the input 684 data with a filter. The streams that will be discarded should then be freed 685 by calling deflateEnd. Note that deflateCopy duplicates the internal 686 compression state which can be quite large, so this strategy is slow and can 687 consume lots of memory. 688 689 deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not 690 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent 691 (such as zalloc being Z_NULL). msg is left unchanged in both source and 692 destination. 693 */ 694 695 ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm)); 696 /* 697 This function is equivalent to deflateEnd followed by deflateInit, but 698 does not free and reallocate the internal compression state. The stream 699 will leave the compression level and any other attributes that may have been 700 set unchanged. 701 702 deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source 703 stream state was inconsistent (such as zalloc or state being Z_NULL). 704 */ 705 706 ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm, 707 int level, 708 int strategy)); 709 /* 710 Dynamically update the compression level and compression strategy. The 711 interpretation of level and strategy is as in deflateInit2(). This can be 712 used to switch between compression and straight copy of the input data, or 713 to switch to a different kind of input data requiring a different strategy. 714 If the compression approach (which is a function of the level) or the 715 strategy is changed, and if there have been any deflate() calls since the 716 state was initialized or reset, then the input available so far is 717 compressed with the old level and strategy using deflate(strm, Z_BLOCK). 718 There are three approaches for the compression levels 0, 1..3, and 4..9 719 respectively. The new level and strategy will take effect at the next call 720 of deflate(). 721 722 If a deflate(strm, Z_BLOCK) is performed by deflateParams(), and it does 723 not have enough output space to complete, then the parameter change will not 724 take effect. In this case, deflateParams() can be called again with the 725 same parameters and more output space to try again. 726 727 In order to assure a change in the parameters on the first try, the 728 deflate stream should be flushed using deflate() with Z_BLOCK or other flush 729 request until strm.avail_out is not zero, before calling deflateParams(). 730 Then no more input data should be provided before the deflateParams() call. 731 If this is done, the old level and strategy will be applied to the data 732 compressed before deflateParams(), and the new level and strategy will be 733 applied to the the data compressed after deflateParams(). 734 735 deflateParams returns Z_OK on success, Z_STREAM_ERROR if the source stream 736 state was inconsistent or if a parameter was invalid, or Z_BUF_ERROR if 737 there was not enough output space to complete the compression of the 738 available input data before a change in the strategy or approach. Note that 739 in the case of a Z_BUF_ERROR, the parameters are not changed. A return 740 value of Z_BUF_ERROR is not fatal, in which case deflateParams() can be 741 retried with more output space. 742 */ 743 744 ZEXTERN int ZEXPORT deflateTune OF((z_streamp strm, 745 int good_length, 746 int max_lazy, 747 int nice_length, 748 int max_chain)); 749 /* 750 Fine tune deflate's internal compression parameters. This should only be 751 used by someone who understands the algorithm used by zlib's deflate for 752 searching for the best matching string, and even then only by the most 753 fanatic optimizer trying to squeeze out the last compressed bit for their 754 specific input data. Read the deflate.c source code for the meaning of the 755 max_lazy, good_length, nice_length, and max_chain parameters. 756 757 deflateTune() can be called after deflateInit() or deflateInit2(), and 758 returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream. 759 */ 760 761 ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm, 762 uLong sourceLen)); 763 /* 764 deflateBound() returns an upper bound on the compressed size after 765 deflation of sourceLen bytes. It must be called after deflateInit() or 766 deflateInit2(), and after deflateSetHeader(), if used. This would be used 767 to allocate an output buffer for deflation in a single pass, and so would be 768 called before deflate(). If that first deflate() call is provided the 769 sourceLen input bytes, an output buffer allocated to the size returned by 770 deflateBound(), and the flush value Z_FINISH, then deflate() is guaranteed 771 to return Z_STREAM_END. Note that it is possible for the compressed size to 772 be larger than the value returned by deflateBound() if flush options other 773 than Z_FINISH or Z_NO_FLUSH are used. 774 */ 775 776 ZEXTERN int ZEXPORT deflatePending OF((z_streamp strm, 777 unsigned *pending, 778 int *bits)); 779 /* 780 deflatePending() returns the number of bytes and bits of output that have 781 been generated, but not yet provided in the available output. The bytes not 782 provided would be due to the available output space having being consumed. 783 The number of bits of output not provided are between 0 and 7, where they 784 await more bits to join them in order to fill out a full byte. If pending 785 or bits are Z_NULL, then those values are not set. 786 787 deflatePending returns Z_OK if success, or Z_STREAM_ERROR if the source 788 stream state was inconsistent. 789 */ 790 791 ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm, 792 int bits, 793 int value)); 794 /* 795 deflatePrime() inserts bits in the deflate output stream. The intent 796 is that this function is used to start off the deflate output with the bits 797 leftover from a previous deflate stream when appending to it. As such, this 798 function can only be used for raw deflate, and must be used before the first 799 deflate() call after a deflateInit2() or deflateReset(). bits must be less 800 than or equal to 16, and that many of the least significant bits of value 801 will be inserted in the output. 802 803 deflatePrime returns Z_OK if success, Z_BUF_ERROR if there was not enough 804 room in the internal buffer to insert the bits, or Z_STREAM_ERROR if the 805 source stream state was inconsistent. 806 */ 807 808 ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm, 809 gz_headerp head)); 810 /* 811 deflateSetHeader() provides gzip header information for when a gzip 812 stream is requested by deflateInit2(). deflateSetHeader() may be called 813 after deflateInit2() or deflateReset() and before the first call of 814 deflate(). The text, time, os, extra field, name, and comment information 815 in the provided gz_header structure are written to the gzip header (xflag is 816 ignored -- the extra flags are set according to the compression level). The 817 caller must assure that, if not Z_NULL, name and comment are terminated with 818 a zero byte, and that if extra is not Z_NULL, that extra_len bytes are 819 available there. If hcrc is true, a gzip header crc is included. Note that 820 the current versions of the command-line version of gzip (up through version 821 1.3.x) do not support header crc's, and will report that it is a "multi-part 822 gzip file" and give up. 823 824 If deflateSetHeader is not used, the default gzip header has text false, 825 the time set to zero, and os set to 255, with no extra, name, or comment 826 fields. The gzip header is returned to the default state by deflateReset(). 827 828 deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source 829 stream state was inconsistent. 830 */ 831 832 /* 833 ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm, 834 int windowBits)); 835 836 This is another version of inflateInit with an extra parameter. The 837 fields next_in, avail_in, zalloc, zfree and opaque must be initialized 838 before by the caller. 839 840 The windowBits parameter is the base two logarithm of the maximum window 841 size (the size of the history buffer). It should be in the range 8..15 for 842 this version of the library. The default value is 15 if inflateInit is used 843 instead. windowBits must be greater than or equal to the windowBits value 844 provided to deflateInit2() while compressing, or it must be equal to 15 if 845 deflateInit2() was not used. If a compressed stream with a larger window 846 size is given as input, inflate() will return with the error code 847 Z_DATA_ERROR instead of trying to allocate a larger window. 848 849 windowBits can also be zero to request that inflate use the window size in 850 the zlib header of the compressed stream. 851 852 windowBits can also be -8..-15 for raw inflate. In this case, -windowBits 853 determines the window size. inflate() will then process raw deflate data, 854 not looking for a zlib or gzip header, not generating a check value, and not 855 looking for any check values for comparison at the end of the stream. This 856 is for use with other formats that use the deflate compressed data format 857 such as zip. Those formats provide their own check values. If a custom 858 format is developed using the raw deflate format for compressed data, it is 859 recommended that a check value such as an Adler-32 or a CRC-32 be applied to 860 the uncompressed data as is done in the zlib, gzip, and zip formats. For 861 most applications, the zlib format should be used as is. Note that comments 862 above on the use in deflateInit2() applies to the magnitude of windowBits. 863 864 windowBits can also be greater than 15 for optional gzip decoding. Add 865 32 to windowBits to enable zlib and gzip decoding with automatic header 866 detection, or add 16 to decode only the gzip format (the zlib format will 867 return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is a 868 CRC-32 instead of an Adler-32. Unlike the gunzip utility and gzread() (see 869 below), inflate() will *not* automatically decode concatenated gzip members. 870 inflate() will return Z_STREAM_END at the end of the gzip member. The state 871 would need to be reset to continue decoding a subsequent gzip member. This 872 *must* be done if there is more data after a gzip member, in order for the 873 decompression to be compliant with the gzip standard (RFC 1952). 874 875 inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 876 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the 877 version assumed by the caller, or Z_STREAM_ERROR if the parameters are 878 invalid, such as a null pointer to the structure. msg is set to null if 879 there is no error message. inflateInit2 does not perform any decompression 880 apart from possibly reading the zlib header if present: actual decompression 881 will be done by inflate(). (So next_in and avail_in may be modified, but 882 next_out and avail_out are unused and unchanged.) The current implementation 883 of inflateInit2() does not process any header information -- that is 884 deferred until inflate() is called. 885 */ 886 887 ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm, 888 const Bytef *dictionary, 889 uInt dictLength)); 890 /* 891 Initializes the decompression dictionary from the given uncompressed byte 892 sequence. This function must be called immediately after a call of inflate, 893 if that call returned Z_NEED_DICT. The dictionary chosen by the compressor 894 can be determined from the Adler-32 value returned by that call of inflate. 895 The compressor and decompressor must use exactly the same dictionary (see 896 deflateSetDictionary). For raw inflate, this function can be called at any 897 time to set the dictionary. If the provided dictionary is smaller than the 898 window and there is already data in the window, then the provided dictionary 899 will amend what's there. The application must insure that the dictionary 900 that was used for compression is provided. 901 902 inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a 903 parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is 904 inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the 905 expected one (incorrect Adler-32 value). inflateSetDictionary does not 906 perform any decompression: this will be done by subsequent calls of 907 inflate(). 908 */ 909 910 ZEXTERN int ZEXPORT inflateGetDictionary OF((z_streamp strm, 911 Bytef *dictionary, 912 uInt *dictLength)); 913 /* 914 Returns the sliding dictionary being maintained by inflate. dictLength is 915 set to the number of bytes in the dictionary, and that many bytes are copied 916 to dictionary. dictionary must have enough space, where 32768 bytes is 917 always enough. If inflateGetDictionary() is called with dictionary equal to 918 Z_NULL, then only the dictionary length is returned, and nothing is copied. 919 Similary, if dictLength is Z_NULL, then it is not set. 920 921 inflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the 922 stream state is inconsistent. 923 */ 924 925 ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm)); 926 /* 927 Skips invalid compressed data until a possible full flush point (see above 928 for the description of deflate with Z_FULL_FLUSH) can be found, or until all 929 available input is skipped. No output is provided. 930 931 inflateSync searches for a 00 00 FF FF pattern in the compressed data. 932 All full flush points have this pattern, but not all occurrences of this 933 pattern are full flush points. 934 935 inflateSync returns Z_OK if a possible full flush point has been found, 936 Z_BUF_ERROR if no more input was provided, Z_DATA_ERROR if no flush point 937 has been found, or Z_STREAM_ERROR if the stream structure was inconsistent. 938 In the success case, the application may save the current current value of 939 total_in which indicates where valid compressed data was found. In the 940 error case, the application may repeatedly call inflateSync, providing more 941 input each time, until success or end of the input data. 942 */ 943 944 ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest, 945 z_streamp source)); 946 /* 947 Sets the destination stream as a complete copy of the source stream. 948 949 This function can be useful when randomly accessing a large stream. The 950 first pass through the stream can periodically record the inflate state, 951 allowing restarting inflate at those points when randomly accessing the 952 stream. 953 954 inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not 955 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent 956 (such as zalloc being Z_NULL). msg is left unchanged in both source and 957 destination. 958 */ 959 960 ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm)); 961 /* 962 This function is equivalent to inflateEnd followed by inflateInit, 963 but does not free and reallocate the internal decompression state. The 964 stream will keep attributes that may have been set by inflateInit2. 965 966 inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source 967 stream state was inconsistent (such as zalloc or state being Z_NULL). 968 */ 969 970 ZEXTERN int ZEXPORT inflateReset2 OF((z_streamp strm, 971 int windowBits)); 972 /* 973 This function is the same as inflateReset, but it also permits changing 974 the wrap and window size requests. The windowBits parameter is interpreted 975 the same as it is for inflateInit2. If the window size is changed, then the 976 memory allocated for the window is freed, and the window will be reallocated 977 by inflate() if needed. 978 979 inflateReset2 returns Z_OK if success, or Z_STREAM_ERROR if the source 980 stream state was inconsistent (such as zalloc or state being Z_NULL), or if 981 the windowBits parameter is invalid. 982 */ 983 984 ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm, 985 int bits, 986 int value)); 987 /* 988 This function inserts bits in the inflate input stream. The intent is 989 that this function is used to start inflating at a bit position in the 990 middle of a byte. The provided bits will be used before any bytes are used 991 from next_in. This function should only be used with raw inflate, and 992 should be used before the first inflate() call after inflateInit2() or 993 inflateReset(). bits must be less than or equal to 16, and that many of the 994 least significant bits of value will be inserted in the input. 995 996 If bits is negative, then the input stream bit buffer is emptied. Then 997 inflatePrime() can be called again to put bits in the buffer. This is used 998 to clear out bits leftover after feeding inflate a block description prior 999 to feeding inflate codes. 1000 1001 inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source 1002 stream state was inconsistent. 1003 */ 1004 1005 ZEXTERN long ZEXPORT inflateMark OF((z_streamp strm)); 1006 /* 1007 This function returns two values, one in the lower 16 bits of the return 1008 value, and the other in the remaining upper bits, obtained by shifting the 1009 return value down 16 bits. If the upper value is -1 and the lower value is 1010 zero, then inflate() is currently decoding information outside of a block. 1011 If the upper value is -1 and the lower value is non-zero, then inflate is in 1012 the middle of a stored block, with the lower value equaling the number of 1013 bytes from the input remaining to copy. If the upper value is not -1, then 1014 it is the number of bits back from the current bit position in the input of 1015 the code (literal or length/distance pair) currently being processed. In 1016 that case the lower value is the number of bytes already emitted for that 1017 code. 1018 1019 A code is being processed if inflate is waiting for more input to complete 1020 decoding of the code, or if it has completed decoding but is waiting for 1021 more output space to write the literal or match data. 1022 1023 inflateMark() is used to mark locations in the input data for random 1024 access, which may be at bit positions, and to note those cases where the 1025 output of a code may span boundaries of random access blocks. The current 1026 location in the input stream can be determined from avail_in and data_type 1027 as noted in the description for the Z_BLOCK flush parameter for inflate. 1028 1029 inflateMark returns the value noted above, or -65536 if the provided 1030 source stream state was inconsistent. 1031 */ 1032 1033 ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm, 1034 gz_headerp head)); 1035 /* 1036 inflateGetHeader() requests that gzip header information be stored in the 1037 provided gz_header structure. inflateGetHeader() may be called after 1038 inflateInit2() or inflateReset(), and before the first call of inflate(). 1039 As inflate() processes the gzip stream, head->done is zero until the header 1040 is completed, at which time head->done is set to one. If a zlib stream is 1041 being decoded, then head->done is set to -1 to indicate that there will be 1042 no gzip header information forthcoming. Note that Z_BLOCK or Z_TREES can be 1043 used to force inflate() to return immediately after header processing is 1044 complete and before any actual data is decompressed. 1045 1046 The text, time, xflags, and os fields are filled in with the gzip header 1047 contents. hcrc is set to true if there is a header CRC. (The header CRC 1048 was valid if done is set to one.) If extra is not Z_NULL, then extra_max 1049 contains the maximum number of bytes to write to extra. Once done is true, 1050 extra_len contains the actual extra field length, and extra contains the 1051 extra field, or that field truncated if extra_max is less than extra_len. 1052 If name is not Z_NULL, then up to name_max characters are written there, 1053 terminated with a zero unless the length is greater than name_max. If 1054 comment is not Z_NULL, then up to comm_max characters are written there, 1055 terminated with a zero unless the length is greater than comm_max. When any 1056 of extra, name, or comment are not Z_NULL and the respective field is not 1057 present in the header, then that field is set to Z_NULL to signal its 1058 absence. This allows the use of deflateSetHeader() with the returned 1059 structure to duplicate the header. However if those fields are set to 1060 allocated memory, then the application will need to save those pointers 1061 elsewhere so that they can be eventually freed. 1062 1063 If inflateGetHeader is not used, then the header information is simply 1064 discarded. The header is always checked for validity, including the header 1065 CRC if present. inflateReset() will reset the process to discard the header 1066 information. The application would need to call inflateGetHeader() again to 1067 retrieve the header from the next gzip stream. 1068 1069 inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source 1070 stream state was inconsistent. 1071 */ 1072 1073 /* 1074 ZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits, 1075 unsigned char FAR *window)); 1076 1077 Initialize the internal stream state for decompression using inflateBack() 1078 calls. The fields zalloc, zfree and opaque in strm must be initialized 1079 before the call. If zalloc and zfree are Z_NULL, then the default library- 1080 derived memory allocation routines are used. windowBits is the base two 1081 logarithm of the window size, in the range 8..15. window is a caller 1082 supplied buffer of that size. Except for special applications where it is 1083 assured that deflate was used with small window sizes, windowBits must be 15 1084 and a 32K byte window must be supplied to be able to decompress general 1085 deflate streams. 1086 1087 See inflateBack() for the usage of these routines. 1088 1089 inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of 1090 the parameters are invalid, Z_MEM_ERROR if the internal state could not be 1091 allocated, or Z_VERSION_ERROR if the version of the library does not match 1092 the version of the header file. 1093 */ 1094 1095 typedef unsigned (*in_func) OF((void FAR *, 1096 z_const unsigned char FAR * FAR *)); 1097 typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned)); 1098 1099 ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm, 1100 in_func in, void FAR *in_desc, 1101 out_func out, void FAR *out_desc)); 1102 /* 1103 inflateBack() does a raw inflate with a single call using a call-back 1104 interface for input and output. This is potentially more efficient than 1105 inflate() for file i/o applications, in that it avoids copying between the 1106 output and the sliding window by simply making the window itself the output 1107 buffer. inflate() can be faster on modern CPUs when used with large 1108 buffers. inflateBack() trusts the application to not change the output 1109 buffer passed by the output function, at least until inflateBack() returns. 1110 1111 inflateBackInit() must be called first to allocate the internal state 1112 and to initialize the state with the user-provided window buffer. 1113 inflateBack() may then be used multiple times to inflate a complete, raw 1114 deflate stream with each call. inflateBackEnd() is then called to free the 1115 allocated state. 1116 1117 A raw deflate stream is one with no zlib or gzip header or trailer. 1118 This routine would normally be used in a utility that reads zip or gzip 1119 files and writes out uncompressed files. The utility would decode the 1120 header and process the trailer on its own, hence this routine expects only 1121 the raw deflate stream to decompress. This is different from the default 1122 behavior of inflate(), which expects a zlib header and trailer around the 1123 deflate stream. 1124 1125 inflateBack() uses two subroutines supplied by the caller that are then 1126 called by inflateBack() for input and output. inflateBack() calls those 1127 routines until it reads a complete deflate stream and writes out all of the 1128 uncompressed data, or until it encounters an error. The function's 1129 parameters and return types are defined above in the in_func and out_func 1130 typedefs. inflateBack() will call in(in_desc, &buf) which should return the 1131 number of bytes of provided input, and a pointer to that input in buf. If 1132 there is no input available, in() must return zero -- buf is ignored in that 1133 case -- and inflateBack() will return a buffer error. inflateBack() will 1134 call out(out_desc, buf, len) to write the uncompressed data buf[0..len-1]. 1135 out() should return zero on success, or non-zero on failure. If out() 1136 returns non-zero, inflateBack() will return with an error. Neither in() nor 1137 out() are permitted to change the contents of the window provided to 1138 inflateBackInit(), which is also the buffer that out() uses to write from. 1139 The length written by out() will be at most the window size. Any non-zero 1140 amount of input may be provided by in(). 1141 1142 For convenience, inflateBack() can be provided input on the first call by 1143 setting strm->next_in and strm->avail_in. If that input is exhausted, then 1144 in() will be called. Therefore strm->next_in must be initialized before 1145 calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called 1146 immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in 1147 must also be initialized, and then if strm->avail_in is not zero, input will 1148 initially be taken from strm->next_in[0 .. strm->avail_in - 1]. 1149 1150 The in_desc and out_desc parameters of inflateBack() is passed as the 1151 first parameter of in() and out() respectively when they are called. These 1152 descriptors can be optionally used to pass any information that the caller- 1153 supplied in() and out() functions need to do their job. 1154 1155 On return, inflateBack() will set strm->next_in and strm->avail_in to 1156 pass back any unused input that was provided by the last in() call. The 1157 return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR 1158 if in() or out() returned an error, Z_DATA_ERROR if there was a format error 1159 in the deflate stream (in which case strm->msg is set to indicate the nature 1160 of the error), or Z_STREAM_ERROR if the stream was not properly initialized. 1161 In the case of Z_BUF_ERROR, an input or output error can be distinguished 1162 using strm->next_in which will be Z_NULL only if in() returned an error. If 1163 strm->next_in is not Z_NULL, then the Z_BUF_ERROR was due to out() returning 1164 non-zero. (in() will always be called before out(), so strm->next_in is 1165 assured to be defined if out() returns non-zero.) Note that inflateBack() 1166 cannot return Z_OK. 1167 */ 1168 1169 ZEXTERN int ZEXPORT inflateBackEnd OF((z_streamp strm)); 1170 /* 1171 All memory allocated by inflateBackInit() is freed. 1172 1173 inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream 1174 state was inconsistent. 1175 */ 1176 1177 ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void)); 1178 /* Return flags indicating compile-time options. 1179 1180 Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other: 1181 1.0: size of uInt 1182 3.2: size of uLong 1183 5.4: size of voidpf (pointer) 1184 7.6: size of z_off_t 1185 1186 Compiler, assembler, and debug options: 1187 8: ZLIB_DEBUG 1188 9: ASMV or ASMINF -- use ASM code 1189 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention 1190 11: 0 (reserved) 1191 1192 One-time table building (smaller code, but not thread-safe if true): 1193 12: BUILDFIXED -- build static block decoding tables when needed 1194 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed 1195 14,15: 0 (reserved) 1196 1197 Library content (indicates missing functionality): 1198 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking 1199 deflate code when not needed) 1200 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect 1201 and decode gzip streams (to avoid linking crc code) 1202 18-19: 0 (reserved) 1203 1204 Operation variations (changes in library functionality): 1205 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate 1206 21: FASTEST -- deflate algorithm with only one, lowest compression level 1207 22,23: 0 (reserved) 1208 1209 The sprintf variant used by gzprintf (zero is best): 1210 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format 1211 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure! 1212 26: 0 = returns value, 1 = void -- 1 means inferred string length returned 1213 1214 Remainder: 1215 27-31: 0 (reserved) 1216 */ 1217 1218 #ifndef Z_SOLO 1219 1220 /* utility functions */ 1221 1222 /* 1223 The following utility functions are implemented on top of the basic 1224 stream-oriented functions. To simplify the interface, some default options 1225 are assumed (compression level and memory usage, standard memory allocation 1226 functions). The source code of these utility functions can be modified if 1227 you need special options. 1228 */ 1229 1230 ZEXTERN int ZEXPORT compress OF((Bytef *dest, uLongf *destLen, 1231 const Bytef *source, uLong sourceLen)); 1232 /* 1233 Compresses the source buffer into the destination buffer. sourceLen is 1234 the byte length of the source buffer. Upon entry, destLen is the total size 1235 of the destination buffer, which must be at least the value returned by 1236 compressBound(sourceLen). Upon exit, destLen is the actual size of the 1237 compressed data. compress() is equivalent to compress2() with a level 1238 parameter of Z_DEFAULT_COMPRESSION. 1239 1240 compress returns Z_OK if success, Z_MEM_ERROR if there was not 1241 enough memory, Z_BUF_ERROR if there was not enough room in the output 1242 buffer. 1243 */ 1244 1245 ZEXTERN int ZEXPORT compress2 OF((Bytef *dest, uLongf *destLen, 1246 const Bytef *source, uLong sourceLen, 1247 int level)); 1248 /* 1249 Compresses the source buffer into the destination buffer. The level 1250 parameter has the same meaning as in deflateInit. sourceLen is the byte 1251 length of the source buffer. Upon entry, destLen is the total size of the 1252 destination buffer, which must be at least the value returned by 1253 compressBound(sourceLen). Upon exit, destLen is the actual size of the 1254 compressed data. 1255 1256 compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 1257 memory, Z_BUF_ERROR if there was not enough room in the output buffer, 1258 Z_STREAM_ERROR if the level parameter is invalid. 1259 */ 1260 1261 ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen)); 1262 /* 1263 compressBound() returns an upper bound on the compressed size after 1264 compress() or compress2() on sourceLen bytes. It would be used before a 1265 compress() or compress2() call to allocate the destination buffer. 1266 */ 1267 1268 ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen, 1269 const Bytef *source, uLong sourceLen)); 1270 /* 1271 Decompresses the source buffer into the destination buffer. sourceLen is 1272 the byte length of the source buffer. Upon entry, destLen is the total size 1273 of the destination buffer, which must be large enough to hold the entire 1274 uncompressed data. (The size of the uncompressed data must have been saved 1275 previously by the compressor and transmitted to the decompressor by some 1276 mechanism outside the scope of this compression library.) Upon exit, destLen 1277 is the actual size of the uncompressed data. 1278 1279 uncompress returns Z_OK if success, Z_MEM_ERROR if there was not 1280 enough memory, Z_BUF_ERROR if there was not enough room in the output 1281 buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete. In 1282 the case where there is not enough room, uncompress() will fill the output 1283 buffer with the uncompressed data up to that point. 1284 */ 1285 1286 ZEXTERN int ZEXPORT uncompress2 OF((Bytef *dest, uLongf *destLen, 1287 const Bytef *source, uLong *sourceLen)); 1288 /* 1289 Same as uncompress, except that sourceLen is a pointer, where the 1290 length of the source is *sourceLen. On return, *sourceLen is the number of 1291 source bytes consumed. 1292 */ 1293 1294 /* gzip file access functions */ 1295 1296 /* 1297 This library supports reading and writing files in gzip (.gz) format with 1298 an interface similar to that of stdio, using the functions that start with 1299 "gz". The gzip format is different from the zlib format. gzip is a gzip 1300 wrapper, documented in RFC 1952, wrapped around a deflate stream. 1301 */ 1302 1303 typedef struct gzFile_s *gzFile; /* semi-opaque gzip file descriptor */ 1304 1305 /* 1306 ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode)); 1307 1308 Open the gzip (.gz) file at path for reading and decompressing, or 1309 compressing and writing. The mode parameter is as in fopen ("rb" or "wb") 1310 but can also include a compression level ("wb9") or a strategy: 'f' for 1311 filtered data as in "wb6f", 'h' for Huffman-only compression as in "wb1h", 1312 'R' for run-length encoding as in "wb1R", or 'F' for fixed code compression 1313 as in "wb9F". (See the description of deflateInit2 for more information 1314 about the strategy parameter.) 'T' will request transparent writing or 1315 appending with no compression and not using the gzip format. 1316 1317 "a" can be used instead of "w" to request that the gzip stream that will 1318 be written be appended to the file. "+" will result in an error, since 1319 reading and writing to the same gzip file is not supported. The addition of 1320 "x" when writing will create the file exclusively, which fails if the file 1321 already exists. On systems that support it, the addition of "e" when 1322 reading or writing will set the flag to close the file on an execve() call. 1323 1324 These functions, as well as gzip, will read and decode a sequence of gzip 1325 streams in a file. The append function of gzopen() can be used to create 1326 such a file. (Also see gzflush() for another way to do this.) When 1327 appending, gzopen does not test whether the file begins with a gzip stream, 1328 nor does it look for the end of the gzip streams to begin appending. gzopen 1329 will simply append a gzip stream to the existing file. 1330 1331 gzopen can be used to read a file which is not in gzip format; in this 1332 case gzread will directly read from the file without decompression. When 1333 reading, this will be detected automatically by looking for the magic two- 1334 byte gzip header. 1335 1336 gzopen returns NULL if the file could not be opened, if there was 1337 insufficient memory to allocate the gzFile state, or if an invalid mode was 1338 specified (an 'r', 'w', or 'a' was not provided, or '+' was provided). 1339 errno can be checked to determine if the reason gzopen failed was that the 1340 file could not be opened. 1341 */ 1342 1343 ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode)); 1344 /* 1345 Associate a gzFile with the file descriptor fd. File descriptors are 1346 obtained from calls like open, dup, creat, pipe or fileno (if the file has 1347 been previously opened with fopen). The mode parameter is as in gzopen. 1348 1349 The next call of gzclose on the returned gzFile will also close the file 1350 descriptor fd, just like fclose(fdopen(fd, mode)) closes the file descriptor 1351 fd. If you want to keep fd open, use fd = dup(fd_keep); gz = gzdopen(fd, 1352 mode);. The duplicated descriptor should be saved to avoid a leak, since 1353 gzdopen does not close fd if it fails. If you are using fileno() to get the 1354 file descriptor from a FILE *, then you will have to use dup() to avoid 1355 double-close()ing the file descriptor. Both gzclose() and fclose() will 1356 close the associated file descriptor, so they need to have different file 1357 descriptors. 1358 1359 gzdopen returns NULL if there was insufficient memory to allocate the 1360 gzFile state, if an invalid mode was specified (an 'r', 'w', or 'a' was not 1361 provided, or '+' was provided), or if fd is -1. The file descriptor is not 1362 used until the next gz* read, write, seek, or close operation, so gzdopen 1363 will not detect if fd is invalid (unless fd is -1). 1364 */ 1365 1366 ZEXTERN int ZEXPORT gzbuffer OF((gzFile file, unsigned size)); 1367 /* 1368 Set the internal buffer size used by this library's functions for file to 1369 size. The default buffer size is 8192 bytes. This function must be called 1370 after gzopen() or gzdopen(), and before any other calls that read or write 1371 the file. The buffer memory allocation is always deferred to the first read 1372 or write. Three times that size in buffer space is allocated. A larger 1373 buffer size of, for example, 64K or 128K bytes will noticeably increase the 1374 speed of decompression (reading). 1375 1376 The new buffer size also affects the maximum length for gzprintf(). 1377 1378 gzbuffer() returns 0 on success, or -1 on failure, such as being called 1379 too late. 1380 */ 1381 1382 ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy)); 1383 /* 1384 Dynamically update the compression level and strategy for file. See the 1385 description of deflateInit2 for the meaning of these parameters. Previously 1386 provided data is flushed before applying the parameter changes. 1387 1388 gzsetparams returns Z_OK if success, Z_STREAM_ERROR if the file was not 1389 opened for writing, Z_ERRNO if there is an error writing the flushed data, 1390 or Z_MEM_ERROR if there is a memory allocation error. 1391 */ 1392 1393 ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len)); 1394 /* 1395 Read and decompress up to len uncompressed bytes from file into buf. If 1396 the input file is not in gzip format, gzread copies the given number of 1397 bytes into the buffer directly from the file. 1398 1399 After reaching the end of a gzip stream in the input, gzread will continue 1400 to read, looking for another gzip stream. Any number of gzip streams may be 1401 concatenated in the input file, and will all be decompressed by gzread(). 1402 If something other than a gzip stream is encountered after a gzip stream, 1403 that remaining trailing garbage is ignored (and no error is returned). 1404 1405 gzread can be used to read a gzip file that is being concurrently written. 1406 Upon reaching the end of the input, gzread will return with the available 1407 data. If the error code returned by gzerror is Z_OK or Z_BUF_ERROR, then 1408 gzclearerr can be used to clear the end of file indicator in order to permit 1409 gzread to be tried again. Z_OK indicates that a gzip stream was completed 1410 on the last gzread. Z_BUF_ERROR indicates that the input file ended in the 1411 middle of a gzip stream. Note that gzread does not return -1 in the event 1412 of an incomplete gzip stream. This error is deferred until gzclose(), which 1413 will return Z_BUF_ERROR if the last gzread ended in the middle of a gzip 1414 stream. Alternatively, gzerror can be used before gzclose to detect this 1415 case. 1416 1417 gzread returns the number of uncompressed bytes actually read, less than 1418 len for end of file, or -1 for error. If len is too large to fit in an int, 1419 then nothing is read, -1 is returned, and the error state is set to 1420 Z_STREAM_ERROR. 1421 */ 1422 1423 ZEXTERN z_size_t ZEXPORT gzfread OF((voidp buf, z_size_t size, z_size_t nitems, 1424 gzFile file)); 1425 /* 1426 Read and decompress up to nitems items of size size from file into buf, 1427 otherwise operating as gzread() does. This duplicates the interface of 1428 stdio's fread(), with size_t request and return types. If the library 1429 defines size_t, then z_size_t is identical to size_t. If not, then z_size_t 1430 is an unsigned integer type that can contain a pointer. 1431 1432 gzfread() returns the number of full items read of size size, or zero if 1433 the end of the file was reached and a full item could not be read, or if 1434 there was an error. gzerror() must be consulted if zero is returned in 1435 order to determine if there was an error. If the multiplication of size and 1436 nitems overflows, i.e. the product does not fit in a z_size_t, then nothing 1437 is read, zero is returned, and the error state is set to Z_STREAM_ERROR. 1438 1439 In the event that the end of file is reached and only a partial item is 1440 available at the end, i.e. the remaining uncompressed data length is not a 1441 multiple of size, then the final partial item is nevetheless read into buf 1442 and the end-of-file flag is set. The length of the partial item read is not 1443 provided, but could be inferred from the result of gztell(). This behavior 1444 is the same as the behavior of fread() implementations in common libraries, 1445 but it prevents the direct use of gzfread() to read a concurrently written 1446 file, reseting and retrying on end-of-file, when size is not 1. 1447 */ 1448 1449 ZEXTERN int ZEXPORT gzwrite OF((gzFile file, voidpc buf, unsigned len)); 1450 /* 1451 Compress and write the len uncompressed bytes at buf to file. gzwrite 1452 returns the number of uncompressed bytes written or 0 in case of error. 1453 */ 1454 1455 ZEXTERN z_size_t ZEXPORT gzfwrite OF((voidpc buf, z_size_t size, 1456 z_size_t nitems, gzFile file)); 1457 /* 1458 Compress and write nitems items of size size from buf to file, duplicating 1459 the interface of stdio's fwrite(), with size_t request and return types. If 1460 the library defines size_t, then z_size_t is identical to size_t. If not, 1461 then z_size_t is an unsigned integer type that can contain a pointer. 1462 1463 gzfwrite() returns the number of full items written of size size, or zero 1464 if there was an error. If the multiplication of size and nitems overflows, 1465 i.e. the product does not fit in a z_size_t, then nothing is written, zero 1466 is returned, and the error state is set to Z_STREAM_ERROR. 1467 */ 1468 1469 ZEXTERN int ZEXPORTVA gzprintf Z_ARG((gzFile file, const char *format, ...)); 1470 /* 1471 Convert, format, compress, and write the arguments (...) to file under 1472 control of the string format, as in fprintf. gzprintf returns the number of 1473 uncompressed bytes actually written, or a negative zlib error code in case 1474 of error. The number of uncompressed bytes written is limited to 8191, or 1475 one less than the buffer size given to gzbuffer(). The caller should assure 1476 that this limit is not exceeded. If it is exceeded, then gzprintf() will 1477 return an error (0) with nothing written. In this case, there may also be a 1478 buffer overflow with unpredictable consequences, which is possible only if 1479 zlib was compiled with the insecure functions sprintf() or vsprintf(), 1480 because the secure snprintf() or vsnprintf() functions were not available. 1481 This can be determined using zlibCompileFlags(). 1482 */ 1483 1484 ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s)); 1485 /* 1486 Compress and write the given null-terminated string s to file, excluding 1487 the terminating null character. 1488 1489 gzputs returns the number of characters written, or -1 in case of error. 1490 */ 1491 1492 ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len)); 1493 /* 1494 Read and decompress bytes from file into buf, until len-1 characters are 1495 read, or until a newline character is read and transferred to buf, or an 1496 end-of-file condition is encountered. If any characters are read or if len 1497 is one, the string is terminated with a null character. If no characters 1498 are read due to an end-of-file or len is less than one, then the buffer is 1499 left untouched. 1500 1501 gzgets returns buf which is a null-terminated string, or it returns NULL 1502 for end-of-file or in case of error. If there was an error, the contents at 1503 buf are indeterminate. 1504 */ 1505 1506 ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c)); 1507 /* 1508 Compress and write c, converted to an unsigned char, into file. gzputc 1509 returns the value that was written, or -1 in case of error. 1510 */ 1511 1512 ZEXTERN int ZEXPORT gzgetc OF((gzFile file)); 1513 /* 1514 Read and decompress one byte from file. gzgetc returns this byte or -1 1515 in case of end of file or error. This is implemented as a macro for speed. 1516 As such, it does not do all of the checking the other functions do. I.e. 1517 it does not check to see if file is NULL, nor whether the structure file 1518 points to has been clobbered or not. 1519 */ 1520 1521 ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file)); 1522 /* 1523 Push c back onto the stream for file to be read as the first character on 1524 the next read. At least one character of push-back is always allowed. 1525 gzungetc() returns the character pushed, or -1 on failure. gzungetc() will 1526 fail if c is -1, and may fail if a character has been pushed but not read 1527 yet. If gzungetc is used immediately after gzopen or gzdopen, at least the 1528 output buffer size of pushed characters is allowed. (See gzbuffer above.) 1529 The pushed character will be discarded if the stream is repositioned with 1530 gzseek() or gzrewind(). 1531 */ 1532 1533 ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush)); 1534 /* 1535 Flush all pending output to file. The parameter flush is as in the 1536 deflate() function. The return value is the zlib error number (see function 1537 gzerror below). gzflush is only permitted when writing. 1538 1539 If the flush parameter is Z_FINISH, the remaining data is written and the 1540 gzip stream is completed in the output. If gzwrite() is called again, a new 1541 gzip stream will be started in the output. gzread() is able to read such 1542 concatenated gzip streams. 1543 1544 gzflush should be called only when strictly necessary because it will 1545 degrade compression if called too often. 1546 */ 1547 1548 /* 1549 ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file, 1550 z_off_t offset, int whence)); 1551 1552 Set the starting position to offset relative to whence for the next gzread 1553 or gzwrite on file. The offset represents a number of bytes in the 1554 uncompressed data stream. The whence parameter is defined as in lseek(2); 1555 the value SEEK_END is not supported. 1556 1557 If the file is opened for reading, this function is emulated but can be 1558 extremely slow. If the file is opened for writing, only forward seeks are 1559 supported; gzseek then compresses a sequence of zeroes up to the new 1560 starting position. 1561 1562 gzseek returns the resulting offset location as measured in bytes from 1563 the beginning of the uncompressed stream, or -1 in case of error, in 1564 particular if the file is opened for writing and the new starting position 1565 would be before the current position. 1566 */ 1567 1568 ZEXTERN int ZEXPORT gzrewind OF((gzFile file)); 1569 /* 1570 Rewind file. This function is supported only for reading. 1571 1572 gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET). 1573 */ 1574 1575 /* 1576 ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file)); 1577 1578 Return the starting position for the next gzread or gzwrite on file. 1579 This position represents a number of bytes in the uncompressed data stream, 1580 and is zero when starting, even if appending or reading a gzip stream from 1581 the middle of a file using gzdopen(). 1582 1583 gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR) 1584 */ 1585 1586 /* 1587 ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile file)); 1588 1589 Return the current compressed (actual) read or write offset of file. This 1590 offset includes the count of bytes that precede the gzip stream, for example 1591 when appending or when using gzdopen() for reading. When reading, the 1592 offset does not include as yet unused buffered input. This information can 1593 be used for a progress indicator. On error, gzoffset() returns -1. 1594 */ 1595 1596 ZEXTERN int ZEXPORT gzeof OF((gzFile file)); 1597 /* 1598 Return true (1) if the end-of-file indicator for file has been set while 1599 reading, false (0) otherwise. Note that the end-of-file indicator is set 1600 only if the read tried to go past the end of the input, but came up short. 1601 Therefore, just like feof(), gzeof() may return false even if there is no 1602 more data to read, in the event that the last read request was for the exact 1603 number of bytes remaining in the input file. This will happen if the input 1604 file size is an exact multiple of the buffer size. 1605 1606 If gzeof() returns true, then the read functions will return no more data, 1607 unless the end-of-file indicator is reset by gzclearerr() and the input file 1608 has grown since the previous end of file was detected. 1609 */ 1610 1611 ZEXTERN int ZEXPORT gzdirect OF((gzFile file)); 1612 /* 1613 Return true (1) if file is being copied directly while reading, or false 1614 (0) if file is a gzip stream being decompressed. 1615 1616 If the input file is empty, gzdirect() will return true, since the input 1617 does not contain a gzip stream. 1618 1619 If gzdirect() is used immediately after gzopen() or gzdopen() it will 1620 cause buffers to be allocated to allow reading the file to determine if it 1621 is a gzip file. Therefore if gzbuffer() is used, it should be called before 1622 gzdirect(). 1623 1624 When writing, gzdirect() returns true (1) if transparent writing was 1625 requested ("wT" for the gzopen() mode), or false (0) otherwise. (Note: 1626 gzdirect() is not needed when writing. Transparent writing must be 1627 explicitly requested, so the application already knows the answer. When 1628 linking statically, using gzdirect() will include all of the zlib code for 1629 gzip file reading and decompression, which may not be desired.) 1630 */ 1631 1632 ZEXTERN int ZEXPORT gzclose OF((gzFile file)); 1633 /* 1634 Flush all pending output for file, if necessary, close file and 1635 deallocate the (de)compression state. Note that once file is closed, you 1636 cannot call gzerror with file, since its structures have been deallocated. 1637 gzclose must not be called more than once on the same file, just as free 1638 must not be called more than once on the same allocation. 1639 1640 gzclose will return Z_STREAM_ERROR if file is not valid, Z_ERRNO on a 1641 file operation error, Z_MEM_ERROR if out of memory, Z_BUF_ERROR if the 1642 last read ended in the middle of a gzip stream, or Z_OK on success. 1643 */ 1644 1645 ZEXTERN int ZEXPORT gzclose_r OF((gzFile file)); 1646 ZEXTERN int ZEXPORT gzclose_w OF((gzFile file)); 1647 /* 1648 Same as gzclose(), but gzclose_r() is only for use when reading, and 1649 gzclose_w() is only for use when writing or appending. The advantage to 1650 using these instead of gzclose() is that they avoid linking in zlib 1651 compression or decompression code that is not used when only reading or only 1652 writing respectively. If gzclose() is used, then both compression and 1653 decompression code will be included the application when linking to a static 1654 zlib library. 1655 */ 1656 1657 ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum)); 1658 /* 1659 Return the error message for the last error which occurred on file. 1660 errnum is set to zlib error number. If an error occurred in the file system 1661 and not in the compression library, errnum is set to Z_ERRNO and the 1662 application may consult errno to get the exact error code. 1663 1664 The application must not modify the returned string. Future calls to 1665 this function may invalidate the previously returned string. If file is 1666 closed, then the string previously returned by gzerror will no longer be 1667 available. 1668 1669 gzerror() should be used to distinguish errors from end-of-file for those 1670 functions above that do not distinguish those cases in their return values. 1671 */ 1672 1673 ZEXTERN void ZEXPORT gzclearerr OF((gzFile file)); 1674 /* 1675 Clear the error and end-of-file flags for file. This is analogous to the 1676 clearerr() function in stdio. This is useful for continuing to read a gzip 1677 file that is being written concurrently. 1678 */ 1679 1680 #endif /* !Z_SOLO */ 1681 1682 /* checksum functions */ 1683 1684 /* 1685 These functions are not related to compression but are exported 1686 anyway because they might be useful in applications using the compression 1687 library. 1688 */ 1689 1690 ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len)); 1691 /* 1692 Update a running Adler-32 checksum with the bytes buf[0..len-1] and 1693 return the updated checksum. An Adler-32 value is in the range of a 32-bit 1694 unsigned integer. If buf is Z_NULL, this function returns the required 1695 initial value for the checksum. 1696 1697 An Adler-32 checksum is almost as reliable as a CRC-32 but can be computed 1698 much faster. 1699 1700 Usage example: 1701 1702 uLong adler = adler32(0L, Z_NULL, 0); 1703 1704 while (read_buffer(buffer, length) != EOF) { 1705 adler = adler32(adler, buffer, length); 1706 } 1707 if (adler != original_adler) error(); 1708 */ 1709 1710 ZEXTERN uLong ZEXPORT adler32_z OF((uLong adler, const Bytef *buf, 1711 z_size_t len)); 1712 /* 1713 Same as adler32(), but with a size_t length. 1714 */ 1715 1716 /* 1717 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong adler1, uLong adler2, 1718 z_off_t len2)); 1719 1720 Combine two Adler-32 checksums into one. For two sequences of bytes, seq1 1721 and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for 1722 each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of 1723 seq1 and seq2 concatenated, requiring only adler1, adler2, and len2. Note 1724 that the z_off_t type (like off_t) is a signed integer. If len2 is 1725 negative, the result has no meaning or utility. 1726 */ 1727 1728 ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len)); 1729 /* 1730 Update a running CRC-32 with the bytes buf[0..len-1] and return the 1731 updated CRC-32. A CRC-32 value is in the range of a 32-bit unsigned integer. 1732 If buf is Z_NULL, this function returns the required initial value for the 1733 crc. Pre- and post-conditioning (one's complement) is performed within this 1734 function so it shouldn't be done by the application. 1735 1736 Usage example: 1737 1738 uLong crc = crc32(0L, Z_NULL, 0); 1739 1740 while (read_buffer(buffer, length) != EOF) { 1741 crc = crc32(crc, buffer, length); 1742 } 1743 if (crc != original_crc) error(); 1744 */ 1745 1746 ZEXTERN uLong ZEXPORT crc32_z OF((uLong crc, const Bytef *buf, 1747 z_size_t len)); 1748 /* 1749 Same as crc32(), but with a size_t length. 1750 */ 1751 1752 /* 1753 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2)); 1754 1755 Combine two CRC-32 check values into one. For two sequences of bytes, 1756 seq1 and seq2 with lengths len1 and len2, CRC-32 check values were 1757 calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32 1758 check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and 1759 len2. 1760 */ 1761 1762 /* 1763 ZEXTERN uLong ZEXPORT crc32_combine_gen OF((z_off_t len2)); 1764 1765 Return the operator corresponding to length len2, to be used with 1766 crc32_combine_op(). 1767 */ 1768 1769 ZEXTERN uLong ZEXPORT crc32_combine_op OF((uLong crc1, uLong crc2, uLong op)); 1770 /* 1771 Give the same result as crc32_combine(), using op in place of len2. op is 1772 is generated from len2 by crc32_combine_gen(). This will be faster than 1773 crc32_combine() if the generated op is used more than once. 1774 */ 1775 1776 1777 /* various hacks, don't look :) */ 1778 1779 /* deflateInit and inflateInit are macros to allow checking the zlib version 1780 * and the compiler's view of z_stream: 1781 */ 1782 ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level, 1783 const char *version, int stream_size)); 1784 ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm, 1785 const char *version, int stream_size)); 1786 ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method, 1787 int windowBits, int memLevel, 1788 int strategy, const char *version, 1789 int stream_size)); 1790 ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits, 1791 const char *version, int stream_size)); 1792 ZEXTERN int ZEXPORT inflateBackInit_ OF((z_streamp strm, int windowBits, 1793 unsigned char FAR *window, 1794 const char *version, 1795 int stream_size)); 1796 #ifdef Z_PREFIX_SET 1797 # define z_deflateInit(strm, level) \ 1798 deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream)) 1799 # define z_inflateInit(strm) \ 1800 inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream)) 1801 # define z_deflateInit2(strm, level, method, windowBits, memLevel, strategy) \ 1802 deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\ 1803 (strategy), ZLIB_VERSION, (int)sizeof(z_stream)) 1804 # define z_inflateInit2(strm, windowBits) \ 1805 inflateInit2_((strm), (windowBits), ZLIB_VERSION, \ 1806 (int)sizeof(z_stream)) 1807 # define z_inflateBackInit(strm, windowBits, window) \ 1808 inflateBackInit_((strm), (windowBits), (window), \ 1809 ZLIB_VERSION, (int)sizeof(z_stream)) 1810 #else 1811 # define deflateInit(strm, level) \ 1812 deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream)) 1813 # define inflateInit(strm) \ 1814 inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream)) 1815 # define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \ 1816 deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\ 1817 (strategy), ZLIB_VERSION, (int)sizeof(z_stream)) 1818 # define inflateInit2(strm, windowBits) \ 1819 inflateInit2_((strm), (windowBits), ZLIB_VERSION, \ 1820 (int)sizeof(z_stream)) 1821 # define inflateBackInit(strm, windowBits, window) \ 1822 inflateBackInit_((strm), (windowBits), (window), \ 1823 ZLIB_VERSION, (int)sizeof(z_stream)) 1824 #endif 1825 1826 #ifndef Z_SOLO 1827 1828 /* gzgetc() macro and its supporting function and exposed data structure. Note 1829 * that the real internal state is much larger than the exposed structure. 1830 * This abbreviated structure exposes just enough for the gzgetc() macro. The 1831 * user should not mess with these exposed elements, since their names or 1832 * behavior could change in the future, perhaps even capriciously. They can 1833 * only be used by the gzgetc() macro. You have been warned. 1834 */ 1835 struct gzFile_s { 1836 unsigned have; 1837 unsigned char *next; 1838 z_off64_t pos; 1839 }; 1840 ZEXTERN int ZEXPORT gzgetc_ OF((gzFile file)); /* backward compatibility */ 1841 #ifdef Z_PREFIX_SET 1842 # undef z_gzgetc 1843 # define z_gzgetc(g) \ 1844 ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : (gzgetc)(g)) 1845 #else 1846 # define gzgetc(g) \ 1847 ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : (gzgetc)(g)) 1848 #endif 1849 1850 /* provide 64-bit offset functions if _LARGEFILE64_SOURCE defined, and/or 1851 * change the regular functions to 64 bits if _FILE_OFFSET_BITS is 64 (if 1852 * both are true, the application gets the *64 functions, and the regular 1853 * functions are changed to 64 bits) -- in case these are set on systems 1854 * without large file support, _LFS64_LARGEFILE must also be true 1855 */ 1856 #ifdef Z_LARGE64 1857 ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *)); 1858 ZEXTERN z_off64_t ZEXPORT gzseek64 OF((gzFile, z_off64_t, int)); 1859 ZEXTERN z_off64_t ZEXPORT gztell64 OF((gzFile)); 1860 ZEXTERN z_off64_t ZEXPORT gzoffset64 OF((gzFile)); 1861 ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off64_t)); 1862 ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off64_t)); 1863 ZEXTERN uLong ZEXPORT crc32_combine_gen64 OF((z_off64_t)); 1864 #endif 1865 1866 #if !defined(ZLIB_INTERNAL) && defined(Z_WANT64) 1867 # ifdef Z_PREFIX_SET 1868 # define z_gzopen z_gzopen64 1869 # define z_gzseek z_gzseek64 1870 # define z_gztell z_gztell64 1871 # define z_gzoffset z_gzoffset64 1872 # define z_adler32_combine z_adler32_combine64 1873 # define z_crc32_combine z_crc32_combine64 1874 # define z_crc32_combine_gen z_crc32_combine_gen64 1875 # else 1876 # define gzopen gzopen64 1877 # define gzseek gzseek64 1878 # define gztell gztell64 1879 # define gzoffset gzoffset64 1880 # define adler32_combine adler32_combine64 1881 # define crc32_combine crc32_combine64 1882 # define crc32_combine_gen crc32_combine_gen64 1883 # endif 1884 # ifndef Z_LARGE64 1885 ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *)); 1886 ZEXTERN z_off_t ZEXPORT gzseek64 OF((gzFile, z_off_t, int)); 1887 ZEXTERN z_off_t ZEXPORT gztell64 OF((gzFile)); 1888 ZEXTERN z_off_t ZEXPORT gzoffset64 OF((gzFile)); 1889 ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off_t)); 1890 ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off_t)); 1891 ZEXTERN uLong ZEXPORT crc32_combine_gen64 OF((z_off_t)); 1892 # endif 1893 #else 1894 ZEXTERN gzFile ZEXPORT gzopen OF((const char *, const char *)); 1895 ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile, z_off_t, int)); 1896 ZEXTERN z_off_t ZEXPORT gztell OF((gzFile)); 1897 ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile)); 1898 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t)); 1899 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t)); 1900 ZEXTERN uLong ZEXPORT crc32_combine_gen OF((z_off_t)); 1901 #endif 1902 1903 #else /* Z_SOLO */ 1904 1905 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t)); 1906 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t)); 1907 ZEXTERN uLong ZEXPORT crc32_combine_gen OF((z_off_t)); 1908 1909 #endif /* !Z_SOLO */ 1910 1911 /* undocumented functions */ 1912 ZEXTERN const char * ZEXPORT zError OF((int)); 1913 ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp)); 1914 ZEXTERN const z_crc_t FAR * ZEXPORT get_crc_table OF((void)); 1915 ZEXTERN int ZEXPORT inflateUndermine OF((z_streamp, int)); 1916 ZEXTERN int ZEXPORT inflateValidate OF((z_streamp, int)); 1917 ZEXTERN unsigned long ZEXPORT inflateCodesUsed OF ((z_streamp)); 1918 ZEXTERN int ZEXPORT inflateResetKeep OF((z_streamp)); 1919 ZEXTERN int ZEXPORT deflateResetKeep OF((z_streamp)); 1920 #if defined(_WIN32) && !defined(Z_SOLO) 1921 ZEXTERN gzFile ZEXPORT gzopen_w OF((const wchar_t *path, 1922 const char *mode)); 1923 #endif 1924 #if defined(STDC) || defined(Z_HAVE_STDARG_H) 1925 # ifndef Z_SOLO 1926 ZEXTERN int ZEXPORTVA gzvprintf Z_ARG((gzFile file, 1927 const char *format, 1928 va_list va)); 1929 # endif 1930 #endif 1931 1932 #ifdef __cplusplus 1933 } 1934 #endif 1935 1936 #endif /* ZLIB_H */ 1937