1 /* $NetBSD: zlib.h,v 1.8 2024/09/22 19:12:27 christos Exp $ */ 2 3 /* zlib.h -- interface of the 'zlib' general purpose compression library 4 version 1.3.1, January 22nd, 2024 5 6 Copyright (C) 1995-2024 Jean-loup Gailly and Mark Adler 7 8 This software is provided 'as-is', without any express or implied 9 warranty. In no event will the authors be held liable for any damages 10 arising from the use of this software. 11 12 Permission is granted to anyone to use this software for any purpose, 13 including commercial applications, and to alter it and redistribute it 14 freely, subject to the following restrictions: 15 16 1. The origin of this software must not be misrepresented; you must not 17 claim that you wrote the original software. If you use this software 18 in a product, an acknowledgment in the product documentation would be 19 appreciated but is not required. 20 2. Altered source versions must be plainly marked as such, and must not be 21 misrepresented as being the original software. 22 3. This notice may not be removed or altered from any source distribution. 23 24 Jean-loup Gailly Mark Adler 25 jloup (at) gzip.org madler (at) alumni.caltech.edu 26 27 28 The data format used by the zlib library is described by RFCs (Request for 29 Comments) 1950 to 1952 in the files http://tools.ietf.org/html/rfc1950 30 (zlib format), rfc1951 (deflate format) and rfc1952 (gzip format). 31 */ 32 33 #ifndef ZLIB_H 34 #define ZLIB_H 35 36 #include "zconf.h" 37 38 #ifdef __cplusplus 39 extern "C" { 40 #endif 41 42 #define ZLIB_VERSION "1.3.1" 43 #define ZLIB_VERNUM 0x1310 44 #define ZLIB_VER_MAJOR 1 45 #define ZLIB_VER_MINOR 3 46 #define ZLIB_VER_REVISION 1 47 #define ZLIB_VER_SUBREVISION 0 48 49 /* 50 The 'zlib' compression library provides in-memory compression and 51 decompression functions, including integrity checks of the uncompressed data. 52 This version of the library supports only one compression method (deflation) 53 but other algorithms will be added later and will have the same stream 54 interface. 55 56 Compression can be done in a single step if the buffers are large enough, 57 or can be done by repeated calls of the compression function. In the latter 58 case, the application must provide more input and/or consume the output 59 (providing more output space) before each call. 60 61 The compressed data format used by default by the in-memory functions is 62 the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped 63 around a deflate stream, which is itself documented in RFC 1951. 64 65 The library also supports reading and writing files in gzip (.gz) format 66 with an interface similar to that of stdio using the functions that start 67 with "gz". The gzip format is different from the zlib format. gzip is a 68 gzip wrapper, documented in RFC 1952, wrapped around a deflate stream. 69 70 This library can optionally read and write gzip and raw deflate streams in 71 memory as well. 72 73 The zlib format was designed to be compact and fast for use in memory 74 and on communications channels. The gzip format was designed for single- 75 file compression on file systems, has a larger header than zlib to maintain 76 directory information, and uses a different, slower check method than zlib. 77 78 The library does not install any signal handler. The decoder checks 79 the consistency of the compressed data, so the library should never crash 80 even in the case of corrupted input. 81 */ 82 83 typedef voidpf (*alloc_func)(voidpf opaque, uInt items, uInt size); 84 typedef void (*free_func)(voidpf opaque, voidpf address); 85 86 struct internal_state; 87 88 typedef struct z_stream_s { 89 z_const Bytef *next_in; /* next input byte */ 90 uInt avail_in; /* number of bytes available at next_in */ 91 uLong total_in; /* total number of input bytes read so far */ 92 93 Bytef *next_out; /* next output byte will go here */ 94 uInt avail_out; /* remaining free space at next_out */ 95 uLong total_out; /* total number of bytes output so far */ 96 97 z_const char *msg; /* last error message, NULL if no error */ 98 struct internal_state FAR *state; /* not visible by applications */ 99 100 alloc_func zalloc; /* used to allocate the internal state */ 101 free_func zfree; /* used to free the internal state */ 102 voidpf opaque; /* private data object passed to zalloc and zfree */ 103 104 int data_type; /* best guess about the data type: binary or text 105 for deflate, or the decoding state for inflate */ 106 uLong adler; /* Adler-32 or CRC-32 value of the uncompressed data */ 107 uLong reserved; /* reserved for future use */ 108 } z_stream; 109 110 typedef z_stream FAR *z_streamp; 111 112 /* 113 gzip header information passed to and from zlib routines. See RFC 1952 114 for more details on the meanings of these fields. 115 */ 116 typedef struct gz_header_s { 117 int text; /* true if compressed data believed to be text */ 118 uLong time; /* modification time */ 119 int xflags; /* extra flags (not used when writing a gzip file) */ 120 int os; /* operating system */ 121 Bytef *extra; /* pointer to extra field or Z_NULL if none */ 122 uInt extra_len; /* extra field length (valid if extra != Z_NULL) */ 123 uInt extra_max; /* space at extra (only when reading header) */ 124 Bytef *name; /* pointer to zero-terminated file name or Z_NULL */ 125 uInt name_max; /* space at name (only when reading header) */ 126 Bytef *comment; /* pointer to zero-terminated comment or Z_NULL */ 127 uInt comm_max; /* space at comment (only when reading header) */ 128 int hcrc; /* true if there was or will be a header crc */ 129 int done; /* true when done reading gzip header (not used 130 when writing a gzip file) */ 131 } gz_header; 132 133 typedef gz_header FAR *gz_headerp; 134 135 /* 136 The application must update next_in and avail_in when avail_in has dropped 137 to zero. It must update next_out and avail_out when avail_out has dropped 138 to zero. The application must initialize zalloc, zfree and opaque before 139 calling the init function. All other fields are set by the compression 140 library and must not be updated by the application. 141 142 The opaque value provided by the application will be passed as the first 143 parameter for calls of zalloc and zfree. This can be useful for custom 144 memory management. The compression library attaches no meaning to the 145 opaque value. 146 147 zalloc must return Z_NULL if there is not enough memory for the object. 148 If zlib is used in a multi-threaded application, zalloc and zfree must be 149 thread safe. In that case, zlib is thread-safe. When zalloc and zfree are 150 Z_NULL on entry to the initialization function, they are set to internal 151 routines that use the standard library functions malloc() and free(). 152 153 On 16-bit systems, the functions zalloc and zfree must be able to allocate 154 exactly 65536 bytes, but will not be required to allocate more than this if 155 the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, pointers 156 returned by zalloc for objects of exactly 65536 bytes *must* have their 157 offset normalized to zero. The default allocation function provided by this 158 library ensures this (see zutil.c). To reduce memory requirements and avoid 159 any allocation of 64K objects, at the expense of compression ratio, compile 160 the library with -DMAX_WBITS=14 (see zconf.h). 161 162 The fields total_in and total_out can be used for statistics or progress 163 reports. After compression, total_in holds the total size of the 164 uncompressed data and may be saved for use by the decompressor (particularly 165 if the decompressor wants to decompress everything in a single step). 166 */ 167 168 /* constants */ 169 170 #define Z_NO_FLUSH 0 171 #define Z_PARTIAL_FLUSH 1 172 #define Z_SYNC_FLUSH 2 173 #define Z_FULL_FLUSH 3 174 #define Z_FINISH 4 175 #define Z_BLOCK 5 176 #define Z_TREES 6 177 /* Allowed flush values; see deflate() and inflate() below for details */ 178 179 #define Z_OK 0 180 #define Z_STREAM_END 1 181 #define Z_NEED_DICT 2 182 #define Z_ERRNO (-1) 183 #define Z_STREAM_ERROR (-2) 184 #define Z_DATA_ERROR (-3) 185 #define Z_MEM_ERROR (-4) 186 #define Z_BUF_ERROR (-5) 187 #define Z_VERSION_ERROR (-6) 188 /* Return codes for the compression/decompression functions. Negative values 189 * are errors, positive values are used for special but normal events. 190 */ 191 192 #define Z_NO_COMPRESSION 0 193 #define Z_BEST_SPEED 1 194 #define Z_BEST_COMPRESSION 9 195 #define Z_DEFAULT_COMPRESSION (-1) 196 /* compression levels */ 197 198 #define Z_FILTERED 1 199 #define Z_HUFFMAN_ONLY 2 200 #define Z_RLE 3 201 #define Z_FIXED 4 202 #define Z_DEFAULT_STRATEGY 0 203 /* compression strategy; see deflateInit2() below for details */ 204 205 #define Z_BINARY 0 206 #define Z_TEXT 1 207 #define Z_ASCII Z_TEXT /* for compatibility with 1.2.2 and earlier */ 208 #define Z_UNKNOWN 2 209 /* Possible values of the data_type field for deflate() */ 210 211 #define Z_DEFLATED 8 212 /* The deflate compression method (the only one supported in this version) */ 213 214 #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */ 215 216 #define zlib_version zlibVersion() 217 /* for compatibility with versions < 1.0.2 */ 218 219 220 /* basic functions */ 221 222 ZEXTERN const char * ZEXPORT zlibVersion(void); 223 /* The application can compare zlibVersion and ZLIB_VERSION for consistency. 224 If the first character differs, the library code actually used is not 225 compatible with the zlib.h header file used by the application. This check 226 is automatically made by deflateInit and inflateInit. 227 */ 228 229 /* 230 ZEXTERN int ZEXPORT deflateInit(z_streamp strm, int level); 231 232 Initializes the internal stream state for compression. The fields 233 zalloc, zfree and opaque must be initialized before by the caller. If 234 zalloc and zfree are set to Z_NULL, deflateInit updates them to use default 235 allocation functions. total_in, total_out, adler, and msg are initialized. 236 237 The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9: 238 1 gives best speed, 9 gives best compression, 0 gives no compression at all 239 (the input data is simply copied a block at a time). Z_DEFAULT_COMPRESSION 240 requests a default compromise between speed and compression (currently 241 equivalent to level 6). 242 243 deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough 244 memory, Z_STREAM_ERROR if level is not a valid compression level, or 245 Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible 246 with the version assumed by the caller (ZLIB_VERSION). msg is set to null 247 if there is no error message. deflateInit does not perform any compression: 248 this will be done by deflate(). 249 */ 250 251 252 ZEXTERN int ZEXPORT deflate(z_streamp strm, int flush); 253 /* 254 deflate compresses as much data as possible, and stops when the input 255 buffer becomes empty or the output buffer becomes full. It may introduce 256 some output latency (reading input without producing any output) except when 257 forced to flush. 258 259 The detailed semantics are as follows. deflate performs one or both of the 260 following actions: 261 262 - Compress more input starting at next_in and update next_in and avail_in 263 accordingly. If not all input can be processed (because there is not 264 enough room in the output buffer), next_in and avail_in are updated and 265 processing will resume at this point for the next call of deflate(). 266 267 - Generate more output starting at next_out and update next_out and avail_out 268 accordingly. This action is forced if the parameter flush is non zero. 269 Forcing flush frequently degrades the compression ratio, so this parameter 270 should be set only when necessary. Some output may be provided even if 271 flush is zero. 272 273 Before the call of deflate(), the application should ensure that at least 274 one of the actions is possible, by providing more input and/or consuming more 275 output, and updating avail_in or avail_out accordingly; avail_out should 276 never be zero before the call. The application can consume the compressed 277 output when it wants, for example when the output buffer is full (avail_out 278 == 0), or after each call of deflate(). If deflate returns Z_OK and with 279 zero avail_out, it must be called again after making room in the output 280 buffer because there might be more output pending. See deflatePending(), 281 which can be used if desired to determine whether or not there is more output 282 in that case. 283 284 Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to 285 decide how much data to accumulate before producing output, in order to 286 maximize compression. 287 288 If the parameter flush is set to Z_SYNC_FLUSH, all pending output is 289 flushed to the output buffer and the output is aligned on a byte boundary, so 290 that the decompressor can get all input data available so far. (In 291 particular avail_in is zero after the call if enough output space has been 292 provided before the call.) Flushing may degrade compression for some 293 compression algorithms and so it should be used only when necessary. This 294 completes the current deflate block and follows it with an empty stored block 295 that is three bits plus filler bits to the next byte, followed by four bytes 296 (00 00 ff ff). 297 298 If flush is set to Z_PARTIAL_FLUSH, all pending output is flushed to the 299 output buffer, but the output is not aligned to a byte boundary. All of the 300 input data so far will be available to the decompressor, as for Z_SYNC_FLUSH. 301 This completes the current deflate block and follows it with an empty fixed 302 codes block that is 10 bits long. This assures that enough bytes are output 303 in order for the decompressor to finish the block before the empty fixed 304 codes block. 305 306 If flush is set to Z_BLOCK, a deflate block is completed and emitted, as 307 for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to 308 seven bits of the current block are held to be written as the next byte after 309 the next deflate block is completed. In this case, the decompressor may not 310 be provided enough bits at this point in order to complete decompression of 311 the data provided so far to the compressor. It may need to wait for the next 312 block to be emitted. This is for advanced applications that need to control 313 the emission of deflate blocks. 314 315 If flush is set to Z_FULL_FLUSH, all output is flushed as with 316 Z_SYNC_FLUSH, and the compression state is reset so that decompression can 317 restart from this point if previous compressed data has been damaged or if 318 random access is desired. Using Z_FULL_FLUSH too often can seriously degrade 319 compression. 320 321 If deflate returns with avail_out == 0, this function must be called again 322 with the same value of the flush parameter and more output space (updated 323 avail_out), until the flush is complete (deflate returns with non-zero 324 avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that 325 avail_out is greater than six when the flush marker begins, in order to avoid 326 repeated flush markers upon calling deflate() again when avail_out == 0. 327 328 If the parameter flush is set to Z_FINISH, pending input is processed, 329 pending output is flushed and deflate returns with Z_STREAM_END if there was 330 enough output space. If deflate returns with Z_OK or Z_BUF_ERROR, this 331 function must be called again with Z_FINISH and more output space (updated 332 avail_out) but no more input data, until it returns with Z_STREAM_END or an 333 error. After deflate has returned Z_STREAM_END, the only possible operations 334 on the stream are deflateReset or deflateEnd. 335 336 Z_FINISH can be used in the first deflate call after deflateInit if all the 337 compression is to be done in a single step. In order to complete in one 338 call, avail_out must be at least the value returned by deflateBound (see 339 below). Then deflate is guaranteed to return Z_STREAM_END. If not enough 340 output space is provided, deflate will not return Z_STREAM_END, and it must 341 be called again as described above. 342 343 deflate() sets strm->adler to the Adler-32 checksum of all input read 344 so far (that is, total_in bytes). If a gzip stream is being generated, then 345 strm->adler will be the CRC-32 checksum of the input read so far. (See 346 deflateInit2 below.) 347 348 deflate() may update strm->data_type if it can make a good guess about 349 the input data type (Z_BINARY or Z_TEXT). If in doubt, the data is 350 considered binary. This field is only for information purposes and does not 351 affect the compression algorithm in any manner. 352 353 deflate() returns Z_OK if some progress has been made (more input 354 processed or more output produced), Z_STREAM_END if all input has been 355 consumed and all output has been produced (only when flush is set to 356 Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example 357 if next_in or next_out was Z_NULL or the state was inadvertently written over 358 by the application), or Z_BUF_ERROR if no progress is possible (for example 359 avail_in or avail_out was zero). Note that Z_BUF_ERROR is not fatal, and 360 deflate() can be called again with more input and more output space to 361 continue compressing. 362 */ 363 364 365 ZEXTERN int ZEXPORT deflateEnd(z_streamp strm); 366 /* 367 All dynamically allocated data structures for this stream are freed. 368 This function discards any unprocessed input and does not flush any pending 369 output. 370 371 deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the 372 stream state was inconsistent, Z_DATA_ERROR if the stream was freed 373 prematurely (some input or output was discarded). In the error case, msg 374 may be set but then points to a static string (which must not be 375 deallocated). 376 */ 377 378 379 /* 380 ZEXTERN int ZEXPORT inflateInit(z_streamp strm); 381 382 Initializes the internal stream state for decompression. The fields 383 next_in, avail_in, zalloc, zfree and opaque must be initialized before by 384 the caller. In the current version of inflate, the provided input is not 385 read or consumed. The allocation of a sliding window will be deferred to 386 the first call of inflate (if the decompression does not complete on the 387 first call). If zalloc and zfree are set to Z_NULL, inflateInit updates 388 them to use default allocation functions. total_in, total_out, adler, and 389 msg are initialized. 390 391 inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough 392 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the 393 version assumed by the caller, or Z_STREAM_ERROR if the parameters are 394 invalid, such as a null pointer to the structure. msg is set to null if 395 there is no error message. inflateInit does not perform any decompression. 396 Actual decompression will be done by inflate(). So next_in, and avail_in, 397 next_out, and avail_out are unused and unchanged. The current 398 implementation of inflateInit() does not process any header information -- 399 that is deferred until inflate() is called. 400 */ 401 402 403 ZEXTERN int ZEXPORT inflate(z_streamp strm, int flush); 404 /* 405 inflate decompresses as much data as possible, and stops when the input 406 buffer becomes empty or the output buffer becomes full. It may introduce 407 some output latency (reading input without producing any output) except when 408 forced to flush. 409 410 The detailed semantics are as follows. inflate performs one or both of the 411 following actions: 412 413 - Decompress more input starting at next_in and update next_in and avail_in 414 accordingly. If not all input can be processed (because there is not 415 enough room in the output buffer), then next_in and avail_in are updated 416 accordingly, and processing will resume at this point for the next call of 417 inflate(). 418 419 - Generate more output starting at next_out and update next_out and avail_out 420 accordingly. inflate() provides as much output as possible, until there is 421 no more input data or no more space in the output buffer (see below about 422 the flush parameter). 423 424 Before the call of inflate(), the application should ensure that at least 425 one of the actions is possible, by providing more input and/or consuming more 426 output, and updating the next_* and avail_* values accordingly. If the 427 caller of inflate() does not provide both available input and available 428 output space, it is possible that there will be no progress made. The 429 application can consume the uncompressed output when it wants, for example 430 when the output buffer is full (avail_out == 0), or after each call of 431 inflate(). If inflate returns Z_OK and with zero avail_out, it must be 432 called again after making room in the output buffer because there might be 433 more output pending. 434 435 The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, Z_FINISH, 436 Z_BLOCK, or Z_TREES. Z_SYNC_FLUSH requests that inflate() flush as much 437 output as possible to the output buffer. Z_BLOCK requests that inflate() 438 stop if and when it gets to the next deflate block boundary. When decoding 439 the zlib or gzip format, this will cause inflate() to return immediately 440 after the header and before the first block. When doing a raw inflate, 441 inflate() will go ahead and process the first block, and will return when it 442 gets to the end of that block, or when it runs out of data. 443 444 The Z_BLOCK option assists in appending to or combining deflate streams. 445 To assist in this, on return inflate() always sets strm->data_type to the 446 number of unused bits in the last byte taken from strm->next_in, plus 64 if 447 inflate() is currently decoding the last block in the deflate stream, plus 448 128 if inflate() returned immediately after decoding an end-of-block code or 449 decoding the complete header up to just before the first byte of the deflate 450 stream. The end-of-block will not be indicated until all of the uncompressed 451 data from that block has been written to strm->next_out. The number of 452 unused bits may in general be greater than seven, except when bit 7 of 453 data_type is set, in which case the number of unused bits will be less than 454 eight. data_type is set as noted here every time inflate() returns for all 455 flush options, and so can be used to determine the amount of currently 456 consumed input in bits. 457 458 The Z_TREES option behaves as Z_BLOCK does, but it also returns when the 459 end of each deflate block header is reached, before any actual data in that 460 block is decoded. This allows the caller to determine the length of the 461 deflate block header for later use in random access within a deflate block. 462 256 is added to the value of strm->data_type when inflate() returns 463 immediately after reaching the end of the deflate block header. 464 465 inflate() should normally be called until it returns Z_STREAM_END or an 466 error. However if all decompression is to be performed in a single step (a 467 single call of inflate), the parameter flush should be set to Z_FINISH. In 468 this case all pending input is processed and all pending output is flushed; 469 avail_out must be large enough to hold all of the uncompressed data for the 470 operation to complete. (The size of the uncompressed data may have been 471 saved by the compressor for this purpose.) The use of Z_FINISH is not 472 required to perform an inflation in one step. However it may be used to 473 inform inflate that a faster approach can be used for the single inflate() 474 call. Z_FINISH also informs inflate to not maintain a sliding window if the 475 stream completes, which reduces inflate's memory footprint. If the stream 476 does not complete, either because not all of the stream is provided or not 477 enough output space is provided, then a sliding window will be allocated and 478 inflate() can be called again to continue the operation as if Z_NO_FLUSH had 479 been used. 480 481 In this implementation, inflate() always flushes as much output as 482 possible to the output buffer, and always uses the faster approach on the 483 first call. So the effects of the flush parameter in this implementation are 484 on the return value of inflate() as noted below, when inflate() returns early 485 when Z_BLOCK or Z_TREES is used, and when inflate() avoids the allocation of 486 memory for a sliding window when Z_FINISH is used. 487 488 If a preset dictionary is needed after this call (see inflateSetDictionary 489 below), inflate sets strm->adler to the Adler-32 checksum of the dictionary 490 chosen by the compressor and returns Z_NEED_DICT; otherwise it sets 491 strm->adler to the Adler-32 checksum of all output produced so far (that is, 492 total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described 493 below. At the end of the stream, inflate() checks that its computed Adler-32 494 checksum is equal to that saved by the compressor and returns Z_STREAM_END 495 only if the checksum is correct. 496 497 inflate() can decompress and check either zlib-wrapped or gzip-wrapped 498 deflate data. The header type is detected automatically, if requested when 499 initializing with inflateInit2(). Any information contained in the gzip 500 header is not retained unless inflateGetHeader() is used. When processing 501 gzip-wrapped deflate data, strm->adler32 is set to the CRC-32 of the output 502 produced so far. The CRC-32 is checked against the gzip trailer, as is the 503 uncompressed length, modulo 2^32. 504 505 inflate() returns Z_OK if some progress has been made (more input processed 506 or more output produced), Z_STREAM_END if the end of the compressed data has 507 been reached and all uncompressed output has been produced, Z_NEED_DICT if a 508 preset dictionary is needed at this point, Z_DATA_ERROR if the input data was 509 corrupted (input stream not conforming to the zlib format or incorrect check 510 value, in which case strm->msg points to a string with a more specific 511 error), Z_STREAM_ERROR if the stream structure was inconsistent (for example 512 next_in or next_out was Z_NULL, or the state was inadvertently written over 513 by the application), Z_MEM_ERROR if there was not enough memory, Z_BUF_ERROR 514 if no progress was possible or if there was not enough room in the output 515 buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and 516 inflate() can be called again with more input and more output space to 517 continue decompressing. If Z_DATA_ERROR is returned, the application may 518 then call inflateSync() to look for a good compression block if a partial 519 recovery of the data is to be attempted. 520 */ 521 522 523 ZEXTERN int ZEXPORT inflateEnd(z_streamp strm); 524 /* 525 All dynamically allocated data structures for this stream are freed. 526 This function discards any unprocessed input and does not flush any pending 527 output. 528 529 inflateEnd returns Z_OK if success, or Z_STREAM_ERROR if the stream state 530 was inconsistent. 531 */ 532 533 534 /* Advanced functions */ 535 536 /* 537 The following functions are needed only in some special applications. 538 */ 539 540 /* 541 ZEXTERN int ZEXPORT deflateInit2(z_streamp strm, 542 int level, 543 int method, 544 int windowBits, 545 int memLevel, 546 int strategy); 547 548 This is another version of deflateInit with more compression options. The 549 fields zalloc, zfree and opaque must be initialized before by the caller. 550 551 The method parameter is the compression method. It must be Z_DEFLATED in 552 this version of the library. 553 554 The windowBits parameter is the base two logarithm of the window size 555 (the size of the history buffer). It should be in the range 8..15 for this 556 version of the library. Larger values of this parameter result in better 557 compression at the expense of memory usage. The default value is 15 if 558 deflateInit is used instead. 559 560 For the current implementation of deflate(), a windowBits value of 8 (a 561 window size of 256 bytes) is not supported. As a result, a request for 8 562 will result in 9 (a 512-byte window). In that case, providing 8 to 563 inflateInit2() will result in an error when the zlib header with 9 is 564 checked against the initialization of inflate(). The remedy is to not use 8 565 with deflateInit2() with this initialization, or at least in that case use 9 566 with inflateInit2(). 567 568 windowBits can also be -8..-15 for raw deflate. In this case, -windowBits 569 determines the window size. deflate() will then generate raw deflate data 570 with no zlib header or trailer, and will not compute a check value. 571 572 windowBits can also be greater than 15 for optional gzip encoding. Add 573 16 to windowBits to write a simple gzip header and trailer around the 574 compressed data instead of a zlib wrapper. The gzip header will have no 575 file name, no extra data, no comment, no modification time (set to zero), no 576 header crc, and the operating system will be set to the appropriate value, 577 if the operating system was determined at compile time. If a gzip stream is 578 being written, strm->adler is a CRC-32 instead of an Adler-32. 579 580 For raw deflate or gzip encoding, a request for a 256-byte window is 581 rejected as invalid, since only the zlib header provides a means of 582 transmitting the window size to the decompressor. 583 584 The memLevel parameter specifies how much memory should be allocated 585 for the internal compression state. memLevel=1 uses minimum memory but is 586 slow and reduces compression ratio; memLevel=9 uses maximum memory for 587 optimal speed. The default value is 8. See zconf.h for total memory usage 588 as a function of windowBits and memLevel. 589 590 The strategy parameter is used to tune the compression algorithm. Use the 591 value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a 592 filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no 593 string match), or Z_RLE to limit match distances to one (run-length 594 encoding). Filtered data consists mostly of small values with a somewhat 595 random distribution. In this case, the compression algorithm is tuned to 596 compress them better. The effect of Z_FILTERED is to force more Huffman 597 coding and less string matching; it is somewhat intermediate between 598 Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as 599 fast as Z_HUFFMAN_ONLY, but give better compression for PNG image data. The 600 strategy parameter only affects the compression ratio but not the 601 correctness of the compressed output even if it is not set appropriately. 602 Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler 603 decoder for special applications. 604 605 deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 606 memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid 607 method), or Z_VERSION_ERROR if the zlib library version (zlib_version) is 608 incompatible with the version assumed by the caller (ZLIB_VERSION). msg is 609 set to null if there is no error message. deflateInit2 does not perform any 610 compression: this will be done by deflate(). 611 */ 612 613 ZEXTERN int ZEXPORT deflateSetDictionary(z_streamp strm, 614 const Bytef *dictionary, 615 uInt dictLength); 616 /* 617 Initializes the compression dictionary from the given byte sequence 618 without producing any compressed output. When using the zlib format, this 619 function must be called immediately after deflateInit, deflateInit2 or 620 deflateReset, and before any call of deflate. When doing raw deflate, this 621 function must be called either before any call of deflate, or immediately 622 after the completion of a deflate block, i.e. after all input has been 623 consumed and all output has been delivered when using any of the flush 624 options Z_BLOCK, Z_PARTIAL_FLUSH, Z_SYNC_FLUSH, or Z_FULL_FLUSH. The 625 compressor and decompressor must use exactly the same dictionary (see 626 inflateSetDictionary). 627 628 The dictionary should consist of strings (byte sequences) that are likely 629 to be encountered later in the data to be compressed, with the most commonly 630 used strings preferably put towards the end of the dictionary. Using a 631 dictionary is most useful when the data to be compressed is short and can be 632 predicted with good accuracy; the data can then be compressed better than 633 with the default empty dictionary. 634 635 Depending on the size of the compression data structures selected by 636 deflateInit or deflateInit2, a part of the dictionary may in effect be 637 discarded, for example if the dictionary is larger than the window size 638 provided in deflateInit or deflateInit2. Thus the strings most likely to be 639 useful should be put at the end of the dictionary, not at the front. In 640 addition, the current implementation of deflate will use at most the window 641 size minus 262 bytes of the provided dictionary. 642 643 Upon return of this function, strm->adler is set to the Adler-32 value 644 of the dictionary; the decompressor may later use this value to determine 645 which dictionary has been used by the compressor. (The Adler-32 value 646 applies to the whole dictionary even if only a subset of the dictionary is 647 actually used by the compressor.) If a raw deflate was requested, then the 648 Adler-32 value is not computed and strm->adler is not set. 649 650 deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a 651 parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is 652 inconsistent (for example if deflate has already been called for this stream 653 or if not at a block boundary for raw deflate). deflateSetDictionary does 654 not perform any compression: this will be done by deflate(). 655 */ 656 657 ZEXTERN int ZEXPORT deflateGetDictionary(z_streamp strm, 658 Bytef *dictionary, 659 uInt *dictLength); 660 /* 661 Returns the sliding dictionary being maintained by deflate. dictLength is 662 set to the number of bytes in the dictionary, and that many bytes are copied 663 to dictionary. dictionary must have enough space, where 32768 bytes is 664 always enough. If deflateGetDictionary() is called with dictionary equal to 665 Z_NULL, then only the dictionary length is returned, and nothing is copied. 666 Similarly, if dictLength is Z_NULL, then it is not set. 667 668 deflateGetDictionary() may return a length less than the window size, even 669 when more than the window size in input has been provided. It may return up 670 to 258 bytes less in that case, due to how zlib's implementation of deflate 671 manages the sliding window and lookahead for matches, where matches can be 672 up to 258 bytes long. If the application needs the last window-size bytes of 673 input, then that would need to be saved by the application outside of zlib. 674 675 deflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the 676 stream state is inconsistent. 677 */ 678 679 ZEXTERN int ZEXPORT deflateCopy(z_streamp dest, 680 z_streamp source); 681 /* 682 Sets the destination stream as a complete copy of the source stream. 683 684 This function can be useful when several compression strategies will be 685 tried, for example when there are several ways of pre-processing the input 686 data with a filter. The streams that will be discarded should then be freed 687 by calling deflateEnd. Note that deflateCopy duplicates the internal 688 compression state which can be quite large, so this strategy is slow and can 689 consume lots of memory. 690 691 deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not 692 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent 693 (such as zalloc being Z_NULL). msg is left unchanged in both source and 694 destination. 695 */ 696 697 ZEXTERN int ZEXPORT deflateReset(z_streamp strm); 698 /* 699 This function is equivalent to deflateEnd followed by deflateInit, but 700 does not free and reallocate the internal compression state. The stream 701 will leave the compression level and any other attributes that may have been 702 set unchanged. total_in, total_out, adler, and msg are initialized. 703 704 deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source 705 stream state was inconsistent (such as zalloc or state being Z_NULL). 706 */ 707 708 ZEXTERN int ZEXPORT deflateParams(z_streamp strm, 709 int level, 710 int strategy); 711 /* 712 Dynamically update the compression level and compression strategy. The 713 interpretation of level and strategy is as in deflateInit2(). This can be 714 used to switch between compression and straight copy of the input data, or 715 to switch to a different kind of input data requiring a different strategy. 716 If the compression approach (which is a function of the level) or the 717 strategy is changed, and if there have been any deflate() calls since the 718 state was initialized or reset, then the input available so far is 719 compressed with the old level and strategy using deflate(strm, Z_BLOCK). 720 There are three approaches for the compression levels 0, 1..3, and 4..9 721 respectively. The new level and strategy will take effect at the next call 722 of deflate(). 723 724 If a deflate(strm, Z_BLOCK) is performed by deflateParams(), and it does 725 not have enough output space to complete, then the parameter change will not 726 take effect. In this case, deflateParams() can be called again with the 727 same parameters and more output space to try again. 728 729 In order to assure a change in the parameters on the first try, the 730 deflate stream should be flushed using deflate() with Z_BLOCK or other flush 731 request until strm.avail_out is not zero, before calling deflateParams(). 732 Then no more input data should be provided before the deflateParams() call. 733 If this is done, the old level and strategy will be applied to the data 734 compressed before deflateParams(), and the new level and strategy will be 735 applied to the data compressed after deflateParams(). 736 737 deflateParams returns Z_OK on success, Z_STREAM_ERROR if the source stream 738 state was inconsistent or if a parameter was invalid, or Z_BUF_ERROR if 739 there was not enough output space to complete the compression of the 740 available input data before a change in the strategy or approach. Note that 741 in the case of a Z_BUF_ERROR, the parameters are not changed. A return 742 value of Z_BUF_ERROR is not fatal, in which case deflateParams() can be 743 retried with more output space. 744 */ 745 746 ZEXTERN int ZEXPORT deflateTune(z_streamp strm, 747 int good_length, 748 int max_lazy, 749 int nice_length, 750 int max_chain); 751 /* 752 Fine tune deflate's internal compression parameters. This should only be 753 used by someone who understands the algorithm used by zlib's deflate for 754 searching for the best matching string, and even then only by the most 755 fanatic optimizer trying to squeeze out the last compressed bit for their 756 specific input data. Read the deflate.c source code for the meaning of the 757 max_lazy, good_length, nice_length, and max_chain parameters. 758 759 deflateTune() can be called after deflateInit() or deflateInit2(), and 760 returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream. 761 */ 762 763 ZEXTERN uLong ZEXPORT deflateBound(z_streamp strm, 764 uLong sourceLen); 765 /* 766 deflateBound() returns an upper bound on the compressed size after 767 deflation of sourceLen bytes. It must be called after deflateInit() or 768 deflateInit2(), and after deflateSetHeader(), if used. This would be used 769 to allocate an output buffer for deflation in a single pass, and so would be 770 called before deflate(). If that first deflate() call is provided the 771 sourceLen input bytes, an output buffer allocated to the size returned by 772 deflateBound(), and the flush value Z_FINISH, then deflate() is guaranteed 773 to return Z_STREAM_END. Note that it is possible for the compressed size to 774 be larger than the value returned by deflateBound() if flush options other 775 than Z_FINISH or Z_NO_FLUSH are used. 776 */ 777 778 ZEXTERN int ZEXPORT deflatePending(z_streamp strm, 779 unsigned *pending, 780 int *bits); 781 /* 782 deflatePending() returns the number of bytes and bits of output that have 783 been generated, but not yet provided in the available output. The bytes not 784 provided would be due to the available output space having being consumed. 785 The number of bits of output not provided are between 0 and 7, where they 786 await more bits to join them in order to fill out a full byte. If pending 787 or bits are Z_NULL, then those values are not set. 788 789 deflatePending returns Z_OK if success, or Z_STREAM_ERROR if the source 790 stream state was inconsistent. 791 */ 792 793 ZEXTERN int ZEXPORT deflatePrime(z_streamp strm, 794 int bits, 795 int value); 796 /* 797 deflatePrime() inserts bits in the deflate output stream. The intent 798 is that this function is used to start off the deflate output with the bits 799 leftover from a previous deflate stream when appending to it. As such, this 800 function can only be used for raw deflate, and must be used before the first 801 deflate() call after a deflateInit2() or deflateReset(). bits must be less 802 than or equal to 16, and that many of the least significant bits of value 803 will be inserted in the output. 804 805 deflatePrime returns Z_OK if success, Z_BUF_ERROR if there was not enough 806 room in the internal buffer to insert the bits, or Z_STREAM_ERROR if the 807 source stream state was inconsistent. 808 */ 809 810 ZEXTERN int ZEXPORT deflateSetHeader(z_streamp strm, 811 gz_headerp head); 812 /* 813 deflateSetHeader() provides gzip header information for when a gzip 814 stream is requested by deflateInit2(). deflateSetHeader() may be called 815 after deflateInit2() or deflateReset() and before the first call of 816 deflate(). The text, time, os, extra field, name, and comment information 817 in the provided gz_header structure are written to the gzip header (xflag is 818 ignored -- the extra flags are set according to the compression level). The 819 caller must assure that, if not Z_NULL, name and comment are terminated with 820 a zero byte, and that if extra is not Z_NULL, that extra_len bytes are 821 available there. If hcrc is true, a gzip header crc is included. Note that 822 the current versions of the command-line version of gzip (up through version 823 1.3.x) do not support header crc's, and will report that it is a "multi-part 824 gzip file" and give up. 825 826 If deflateSetHeader is not used, the default gzip header has text false, 827 the time set to zero, and os set to the current operating system, with no 828 extra, name, or comment fields. The gzip header is returned to the default 829 state by deflateReset(). 830 831 deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source 832 stream state was inconsistent. 833 */ 834 835 /* 836 ZEXTERN int ZEXPORT inflateInit2(z_streamp strm, 837 int windowBits); 838 839 This is another version of inflateInit with an extra parameter. The 840 fields next_in, avail_in, zalloc, zfree and opaque must be initialized 841 before by the caller. 842 843 The windowBits parameter is the base two logarithm of the maximum window 844 size (the size of the history buffer). It should be in the range 8..15 for 845 this version of the library. The default value is 15 if inflateInit is used 846 instead. windowBits must be greater than or equal to the windowBits value 847 provided to deflateInit2() while compressing, or it must be equal to 15 if 848 deflateInit2() was not used. If a compressed stream with a larger window 849 size is given as input, inflate() will return with the error code 850 Z_DATA_ERROR instead of trying to allocate a larger window. 851 852 windowBits can also be zero to request that inflate use the window size in 853 the zlib header of the compressed stream. 854 855 windowBits can also be -8..-15 for raw inflate. In this case, -windowBits 856 determines the window size. inflate() will then process raw deflate data, 857 not looking for a zlib or gzip header, not generating a check value, and not 858 looking for any check values for comparison at the end of the stream. This 859 is for use with other formats that use the deflate compressed data format 860 such as zip. Those formats provide their own check values. If a custom 861 format is developed using the raw deflate format for compressed data, it is 862 recommended that a check value such as an Adler-32 or a CRC-32 be applied to 863 the uncompressed data as is done in the zlib, gzip, and zip formats. For 864 most applications, the zlib format should be used as is. Note that comments 865 above on the use in deflateInit2() applies to the magnitude of windowBits. 866 867 windowBits can also be greater than 15 for optional gzip decoding. Add 868 32 to windowBits to enable zlib and gzip decoding with automatic header 869 detection, or add 16 to decode only the gzip format (the zlib format will 870 return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is a 871 CRC-32 instead of an Adler-32. Unlike the gunzip utility and gzread() (see 872 below), inflate() will *not* automatically decode concatenated gzip members. 873 inflate() will return Z_STREAM_END at the end of the gzip member. The state 874 would need to be reset to continue decoding a subsequent gzip member. This 875 *must* be done if there is more data after a gzip member, in order for the 876 decompression to be compliant with the gzip standard (RFC 1952). 877 878 inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 879 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the 880 version assumed by the caller, or Z_STREAM_ERROR if the parameters are 881 invalid, such as a null pointer to the structure. msg is set to null if 882 there is no error message. inflateInit2 does not perform any decompression 883 apart from possibly reading the zlib header if present: actual decompression 884 will be done by inflate(). (So next_in and avail_in may be modified, but 885 next_out and avail_out are unused and unchanged.) The current implementation 886 of inflateInit2() does not process any header information -- that is 887 deferred until inflate() is called. 888 */ 889 890 ZEXTERN int ZEXPORT inflateSetDictionary(z_streamp strm, 891 const Bytef *dictionary, 892 uInt dictLength); 893 /* 894 Initializes the decompression dictionary from the given uncompressed byte 895 sequence. This function must be called immediately after a call of inflate, 896 if that call returned Z_NEED_DICT. The dictionary chosen by the compressor 897 can be determined from the Adler-32 value returned by that call of inflate. 898 The compressor and decompressor must use exactly the same dictionary (see 899 deflateSetDictionary). For raw inflate, this function can be called at any 900 time to set the dictionary. If the provided dictionary is smaller than the 901 window and there is already data in the window, then the provided dictionary 902 will amend what's there. The application must insure that the dictionary 903 that was used for compression is provided. 904 905 inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a 906 parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is 907 inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the 908 expected one (incorrect Adler-32 value). inflateSetDictionary does not 909 perform any decompression: this will be done by subsequent calls of 910 inflate(). 911 */ 912 913 ZEXTERN int ZEXPORT inflateGetDictionary(z_streamp strm, 914 Bytef *dictionary, 915 uInt *dictLength); 916 /* 917 Returns the sliding dictionary being maintained by inflate. dictLength is 918 set to the number of bytes in the dictionary, and that many bytes are copied 919 to dictionary. dictionary must have enough space, where 32768 bytes is 920 always enough. If inflateGetDictionary() is called with dictionary equal to 921 Z_NULL, then only the dictionary length is returned, and nothing is copied. 922 Similarly, if dictLength is Z_NULL, then it is not set. 923 924 inflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the 925 stream state is inconsistent. 926 */ 927 928 ZEXTERN int ZEXPORT inflateSync(z_streamp strm); 929 /* 930 Skips invalid compressed data until a possible full flush point (see above 931 for the description of deflate with Z_FULL_FLUSH) can be found, or until all 932 available input is skipped. No output is provided. 933 934 inflateSync searches for a 00 00 FF FF pattern in the compressed data. 935 All full flush points have this pattern, but not all occurrences of this 936 pattern are full flush points. 937 938 inflateSync returns Z_OK if a possible full flush point has been found, 939 Z_BUF_ERROR if no more input was provided, Z_DATA_ERROR if no flush point 940 has been found, or Z_STREAM_ERROR if the stream structure was inconsistent. 941 In the success case, the application may save the current value of total_in 942 which indicates where valid compressed data was found. In the error case, 943 the application may repeatedly call inflateSync, providing more input each 944 time, until success or end of the input data. 945 */ 946 947 ZEXTERN int ZEXPORT inflateCopy(z_streamp dest, 948 z_streamp source); 949 /* 950 Sets the destination stream as a complete copy of the source stream. 951 952 This function can be useful when randomly accessing a large stream. The 953 first pass through the stream can periodically record the inflate state, 954 allowing restarting inflate at those points when randomly accessing the 955 stream. 956 957 inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not 958 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent 959 (such as zalloc being Z_NULL). msg is left unchanged in both source and 960 destination. 961 */ 962 963 ZEXTERN int ZEXPORT inflateReset(z_streamp strm); 964 /* 965 This function is equivalent to inflateEnd followed by inflateInit, 966 but does not free and reallocate the internal decompression state. The 967 stream will keep attributes that may have been set by inflateInit2. 968 total_in, total_out, adler, and msg are initialized. 969 970 inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source 971 stream state was inconsistent (such as zalloc or state being Z_NULL). 972 */ 973 974 ZEXTERN int ZEXPORT inflateReset2(z_streamp strm, 975 int windowBits); 976 /* 977 This function is the same as inflateReset, but it also permits changing 978 the wrap and window size requests. The windowBits parameter is interpreted 979 the same as it is for inflateInit2. If the window size is changed, then the 980 memory allocated for the window is freed, and the window will be reallocated 981 by inflate() if needed. 982 983 inflateReset2 returns Z_OK if success, or Z_STREAM_ERROR if the source 984 stream state was inconsistent (such as zalloc or state being Z_NULL), or if 985 the windowBits parameter is invalid. 986 */ 987 988 ZEXTERN int ZEXPORT inflatePrime(z_streamp strm, 989 int bits, 990 int value); 991 /* 992 This function inserts bits in the inflate input stream. The intent is 993 that this function is used to start inflating at a bit position in the 994 middle of a byte. The provided bits will be used before any bytes are used 995 from next_in. This function should only be used with raw inflate, and 996 should be used before the first inflate() call after inflateInit2() or 997 inflateReset(). bits must be less than or equal to 16, and that many of the 998 least significant bits of value will be inserted in the input. 999 1000 If bits is negative, then the input stream bit buffer is emptied. Then 1001 inflatePrime() can be called again to put bits in the buffer. This is used 1002 to clear out bits leftover after feeding inflate a block description prior 1003 to feeding inflate codes. 1004 1005 inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source 1006 stream state was inconsistent. 1007 */ 1008 1009 ZEXTERN long ZEXPORT inflateMark(z_streamp strm); 1010 /* 1011 This function returns two values, one in the lower 16 bits of the return 1012 value, and the other in the remaining upper bits, obtained by shifting the 1013 return value down 16 bits. If the upper value is -1 and the lower value is 1014 zero, then inflate() is currently decoding information outside of a block. 1015 If the upper value is -1 and the lower value is non-zero, then inflate is in 1016 the middle of a stored block, with the lower value equaling the number of 1017 bytes from the input remaining to copy. If the upper value is not -1, then 1018 it is the number of bits back from the current bit position in the input of 1019 the code (literal or length/distance pair) currently being processed. In 1020 that case the lower value is the number of bytes already emitted for that 1021 code. 1022 1023 A code is being processed if inflate is waiting for more input to complete 1024 decoding of the code, or if it has completed decoding but is waiting for 1025 more output space to write the literal or match data. 1026 1027 inflateMark() is used to mark locations in the input data for random 1028 access, which may be at bit positions, and to note those cases where the 1029 output of a code may span boundaries of random access blocks. The current 1030 location in the input stream can be determined from avail_in and data_type 1031 as noted in the description for the Z_BLOCK flush parameter for inflate. 1032 1033 inflateMark returns the value noted above, or -65536 if the provided 1034 source stream state was inconsistent. 1035 */ 1036 1037 ZEXTERN int ZEXPORT inflateGetHeader(z_streamp strm, 1038 gz_headerp head); 1039 /* 1040 inflateGetHeader() requests that gzip header information be stored in the 1041 provided gz_header structure. inflateGetHeader() may be called after 1042 inflateInit2() or inflateReset(), and before the first call of inflate(). 1043 As inflate() processes the gzip stream, head->done is zero until the header 1044 is completed, at which time head->done is set to one. If a zlib stream is 1045 being decoded, then head->done is set to -1 to indicate that there will be 1046 no gzip header information forthcoming. Note that Z_BLOCK or Z_TREES can be 1047 used to force inflate() to return immediately after header processing is 1048 complete and before any actual data is decompressed. 1049 1050 The text, time, xflags, and os fields are filled in with the gzip header 1051 contents. hcrc is set to true if there is a header CRC. (The header CRC 1052 was valid if done is set to one.) If extra is not Z_NULL, then extra_max 1053 contains the maximum number of bytes to write to extra. Once done is true, 1054 extra_len contains the actual extra field length, and extra contains the 1055 extra field, or that field truncated if extra_max is less than extra_len. 1056 If name is not Z_NULL, then up to name_max characters are written there, 1057 terminated with a zero unless the length is greater than name_max. If 1058 comment is not Z_NULL, then up to comm_max characters are written there, 1059 terminated with a zero unless the length is greater than comm_max. When any 1060 of extra, name, or comment are not Z_NULL and the respective field is not 1061 present in the header, then that field is set to Z_NULL to signal its 1062 absence. This allows the use of deflateSetHeader() with the returned 1063 structure to duplicate the header. However if those fields are set to 1064 allocated memory, then the application will need to save those pointers 1065 elsewhere so that they can be eventually freed. 1066 1067 If inflateGetHeader is not used, then the header information is simply 1068 discarded. The header is always checked for validity, including the header 1069 CRC if present. inflateReset() will reset the process to discard the header 1070 information. The application would need to call inflateGetHeader() again to 1071 retrieve the header from the next gzip stream. 1072 1073 inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source 1074 stream state was inconsistent. 1075 */ 1076 1077 /* 1078 ZEXTERN int ZEXPORT inflateBackInit(z_streamp strm, int windowBits, 1079 unsigned char FAR *window); 1080 1081 Initialize the internal stream state for decompression using inflateBack() 1082 calls. The fields zalloc, zfree and opaque in strm must be initialized 1083 before the call. If zalloc and zfree are Z_NULL, then the default library- 1084 derived memory allocation routines are used. windowBits is the base two 1085 logarithm of the window size, in the range 8..15. window is a caller 1086 supplied buffer of that size. Except for special applications where it is 1087 assured that deflate was used with small window sizes, windowBits must be 15 1088 and a 32K byte window must be supplied to be able to decompress general 1089 deflate streams. 1090 1091 See inflateBack() for the usage of these routines. 1092 1093 inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of 1094 the parameters are invalid, Z_MEM_ERROR if the internal state could not be 1095 allocated, or Z_VERSION_ERROR if the version of the library does not match 1096 the version of the header file. 1097 */ 1098 1099 typedef unsigned (*in_func)(void FAR *, 1100 z_const unsigned char FAR * FAR *); 1101 typedef int (*out_func)(void FAR *, unsigned char FAR *, unsigned); 1102 1103 ZEXTERN int ZEXPORT inflateBack(z_streamp strm, 1104 in_func in, void FAR *in_desc, 1105 out_func out, void FAR *out_desc); 1106 /* 1107 inflateBack() does a raw inflate with a single call using a call-back 1108 interface for input and output. This is potentially more efficient than 1109 inflate() for file i/o applications, in that it avoids copying between the 1110 output and the sliding window by simply making the window itself the output 1111 buffer. inflate() can be faster on modern CPUs when used with large 1112 buffers. inflateBack() trusts the application to not change the output 1113 buffer passed by the output function, at least until inflateBack() returns. 1114 1115 inflateBackInit() must be called first to allocate the internal state 1116 and to initialize the state with the user-provided window buffer. 1117 inflateBack() may then be used multiple times to inflate a complete, raw 1118 deflate stream with each call. inflateBackEnd() is then called to free the 1119 allocated state. 1120 1121 A raw deflate stream is one with no zlib or gzip header or trailer. 1122 This routine would normally be used in a utility that reads zip or gzip 1123 files and writes out uncompressed files. The utility would decode the 1124 header and process the trailer on its own, hence this routine expects only 1125 the raw deflate stream to decompress. This is different from the default 1126 behavior of inflate(), which expects a zlib header and trailer around the 1127 deflate stream. 1128 1129 inflateBack() uses two subroutines supplied by the caller that are then 1130 called by inflateBack() for input and output. inflateBack() calls those 1131 routines until it reads a complete deflate stream and writes out all of the 1132 uncompressed data, or until it encounters an error. The function's 1133 parameters and return types are defined above in the in_func and out_func 1134 typedefs. inflateBack() will call in(in_desc, &buf) which should return the 1135 number of bytes of provided input, and a pointer to that input in buf. If 1136 there is no input available, in() must return zero -- buf is ignored in that 1137 case -- and inflateBack() will return a buffer error. inflateBack() will 1138 call out(out_desc, buf, len) to write the uncompressed data buf[0..len-1]. 1139 out() should return zero on success, or non-zero on failure. If out() 1140 returns non-zero, inflateBack() will return with an error. Neither in() nor 1141 out() are permitted to change the contents of the window provided to 1142 inflateBackInit(), which is also the buffer that out() uses to write from. 1143 The length written by out() will be at most the window size. Any non-zero 1144 amount of input may be provided by in(). 1145 1146 For convenience, inflateBack() can be provided input on the first call by 1147 setting strm->next_in and strm->avail_in. If that input is exhausted, then 1148 in() will be called. Therefore strm->next_in must be initialized before 1149 calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called 1150 immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in 1151 must also be initialized, and then if strm->avail_in is not zero, input will 1152 initially be taken from strm->next_in[0 .. strm->avail_in - 1]. 1153 1154 The in_desc and out_desc parameters of inflateBack() is passed as the 1155 first parameter of in() and out() respectively when they are called. These 1156 descriptors can be optionally used to pass any information that the caller- 1157 supplied in() and out() functions need to do their job. 1158 1159 On return, inflateBack() will set strm->next_in and strm->avail_in to 1160 pass back any unused input that was provided by the last in() call. The 1161 return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR 1162 if in() or out() returned an error, Z_DATA_ERROR if there was a format error 1163 in the deflate stream (in which case strm->msg is set to indicate the nature 1164 of the error), or Z_STREAM_ERROR if the stream was not properly initialized. 1165 In the case of Z_BUF_ERROR, an input or output error can be distinguished 1166 using strm->next_in which will be Z_NULL only if in() returned an error. If 1167 strm->next_in is not Z_NULL, then the Z_BUF_ERROR was due to out() returning 1168 non-zero. (in() will always be called before out(), so strm->next_in is 1169 assured to be defined if out() returns non-zero.) Note that inflateBack() 1170 cannot return Z_OK. 1171 */ 1172 1173 ZEXTERN int ZEXPORT inflateBackEnd(z_streamp strm); 1174 /* 1175 All memory allocated by inflateBackInit() is freed. 1176 1177 inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream 1178 state was inconsistent. 1179 */ 1180 1181 ZEXTERN uLong ZEXPORT zlibCompileFlags(void); 1182 /* Return flags indicating compile-time options. 1183 1184 Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other: 1185 1.0: size of uInt 1186 3.2: size of uLong 1187 5.4: size of voidpf (pointer) 1188 7.6: size of z_off_t 1189 1190 Compiler, assembler, and debug options: 1191 8: ZLIB_DEBUG 1192 9: ASMV or ASMINF -- use ASM code 1193 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention 1194 11: 0 (reserved) 1195 1196 One-time table building (smaller code, but not thread-safe if true): 1197 12: BUILDFIXED -- build static block decoding tables when needed 1198 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed 1199 14,15: 0 (reserved) 1200 1201 Library content (indicates missing functionality): 1202 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking 1203 deflate code when not needed) 1204 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect 1205 and decode gzip streams (to avoid linking crc code) 1206 18-19: 0 (reserved) 1207 1208 Operation variations (changes in library functionality): 1209 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate 1210 21: FASTEST -- deflate algorithm with only one, lowest compression level 1211 22,23: 0 (reserved) 1212 1213 The sprintf variant used by gzprintf (zero is best): 1214 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format 1215 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure! 1216 26: 0 = returns value, 1 = void -- 1 means inferred string length returned 1217 1218 Remainder: 1219 27-31: 0 (reserved) 1220 */ 1221 1222 #ifndef Z_SOLO 1223 1224 /* utility functions */ 1225 1226 /* 1227 The following utility functions are implemented on top of the basic 1228 stream-oriented functions. To simplify the interface, some default options 1229 are assumed (compression level and memory usage, standard memory allocation 1230 functions). The source code of these utility functions can be modified if 1231 you need special options. 1232 */ 1233 1234 ZEXTERN int ZEXPORT compress(Bytef *dest, uLongf *destLen, 1235 const Bytef *source, uLong sourceLen); 1236 /* 1237 Compresses the source buffer into the destination buffer. sourceLen is 1238 the byte length of the source buffer. Upon entry, destLen is the total size 1239 of the destination buffer, which must be at least the value returned by 1240 compressBound(sourceLen). Upon exit, destLen is the actual size of the 1241 compressed data. compress() is equivalent to compress2() with a level 1242 parameter of Z_DEFAULT_COMPRESSION. 1243 1244 compress returns Z_OK if success, Z_MEM_ERROR if there was not 1245 enough memory, Z_BUF_ERROR if there was not enough room in the output 1246 buffer. 1247 */ 1248 1249 ZEXTERN int ZEXPORT compress2(Bytef *dest, uLongf *destLen, 1250 const Bytef *source, uLong sourceLen, 1251 int level); 1252 /* 1253 Compresses the source buffer into the destination buffer. The level 1254 parameter has the same meaning as in deflateInit. sourceLen is the byte 1255 length of the source buffer. Upon entry, destLen is the total size of the 1256 destination buffer, which must be at least the value returned by 1257 compressBound(sourceLen). Upon exit, destLen is the actual size of the 1258 compressed data. 1259 1260 compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 1261 memory, Z_BUF_ERROR if there was not enough room in the output buffer, 1262 Z_STREAM_ERROR if the level parameter is invalid. 1263 */ 1264 1265 ZEXTERN uLong ZEXPORT compressBound(uLong sourceLen); 1266 /* 1267 compressBound() returns an upper bound on the compressed size after 1268 compress() or compress2() on sourceLen bytes. It would be used before a 1269 compress() or compress2() call to allocate the destination buffer. 1270 */ 1271 1272 ZEXTERN int ZEXPORT uncompress(Bytef *dest, uLongf *destLen, 1273 const Bytef *source, uLong sourceLen); 1274 /* 1275 Decompresses the source buffer into the destination buffer. sourceLen is 1276 the byte length of the source buffer. Upon entry, destLen is the total size 1277 of the destination buffer, which must be large enough to hold the entire 1278 uncompressed data. (The size of the uncompressed data must have been saved 1279 previously by the compressor and transmitted to the decompressor by some 1280 mechanism outside the scope of this compression library.) Upon exit, destLen 1281 is the actual size of the uncompressed data. 1282 1283 uncompress returns Z_OK if success, Z_MEM_ERROR if there was not 1284 enough memory, Z_BUF_ERROR if there was not enough room in the output 1285 buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete. In 1286 the case where there is not enough room, uncompress() will fill the output 1287 buffer with the uncompressed data up to that point. 1288 */ 1289 1290 ZEXTERN int ZEXPORT uncompress2(Bytef *dest, uLongf *destLen, 1291 const Bytef *source, uLong *sourceLen); 1292 /* 1293 Same as uncompress, except that sourceLen is a pointer, where the 1294 length of the source is *sourceLen. On return, *sourceLen is the number of 1295 source bytes consumed. 1296 */ 1297 1298 /* gzip file access functions */ 1299 1300 /* 1301 This library supports reading and writing files in gzip (.gz) format with 1302 an interface similar to that of stdio, using the functions that start with 1303 "gz". The gzip format is different from the zlib format. gzip is a gzip 1304 wrapper, documented in RFC 1952, wrapped around a deflate stream. 1305 */ 1306 1307 typedef struct gzFile_s *gzFile; /* semi-opaque gzip file descriptor */ 1308 1309 /* 1310 ZEXTERN gzFile ZEXPORT gzopen(const char *path, const char *mode); 1311 1312 Open the gzip (.gz) file at path for reading and decompressing, or 1313 compressing and writing. The mode parameter is as in fopen ("rb" or "wb") 1314 but can also include a compression level ("wb9") or a strategy: 'f' for 1315 filtered data as in "wb6f", 'h' for Huffman-only compression as in "wb1h", 1316 'R' for run-length encoding as in "wb1R", or 'F' for fixed code compression 1317 as in "wb9F". (See the description of deflateInit2 for more information 1318 about the strategy parameter.) 'T' will request transparent writing or 1319 appending with no compression and not using the gzip format. 1320 1321 "a" can be used instead of "w" to request that the gzip stream that will 1322 be written be appended to the file. "+" will result in an error, since 1323 reading and writing to the same gzip file is not supported. The addition of 1324 "x" when writing will create the file exclusively, which fails if the file 1325 already exists. On systems that support it, the addition of "e" when 1326 reading or writing will set the flag to close the file on an execve() call. 1327 1328 These functions, as well as gzip, will read and decode a sequence of gzip 1329 streams in a file. The append function of gzopen() can be used to create 1330 such a file. (Also see gzflush() for another way to do this.) When 1331 appending, gzopen does not test whether the file begins with a gzip stream, 1332 nor does it look for the end of the gzip streams to begin appending. gzopen 1333 will simply append a gzip stream to the existing file. 1334 1335 gzopen can be used to read a file which is not in gzip format; in this 1336 case gzread will directly read from the file without decompression. When 1337 reading, this will be detected automatically by looking for the magic two- 1338 byte gzip header. 1339 1340 gzopen returns NULL if the file could not be opened, if there was 1341 insufficient memory to allocate the gzFile state, or if an invalid mode was 1342 specified (an 'r', 'w', or 'a' was not provided, or '+' was provided). 1343 errno can be checked to determine if the reason gzopen failed was that the 1344 file could not be opened. 1345 */ 1346 1347 ZEXTERN gzFile ZEXPORT gzdopen(int fd, const char *mode); 1348 /* 1349 Associate a gzFile with the file descriptor fd. File descriptors are 1350 obtained from calls like open, dup, creat, pipe or fileno (if the file has 1351 been previously opened with fopen). The mode parameter is as in gzopen. 1352 1353 The next call of gzclose on the returned gzFile will also close the file 1354 descriptor fd, just like fclose(fdopen(fd, mode)) closes the file descriptor 1355 fd. If you want to keep fd open, use fd = dup(fd_keep); gz = gzdopen(fd, 1356 mode);. The duplicated descriptor should be saved to avoid a leak, since 1357 gzdopen does not close fd if it fails. If you are using fileno() to get the 1358 file descriptor from a FILE *, then you will have to use dup() to avoid 1359 double-close()ing the file descriptor. Both gzclose() and fclose() will 1360 close the associated file descriptor, so they need to have different file 1361 descriptors. 1362 1363 gzdopen returns NULL if there was insufficient memory to allocate the 1364 gzFile state, if an invalid mode was specified (an 'r', 'w', or 'a' was not 1365 provided, or '+' was provided), or if fd is -1. The file descriptor is not 1366 used until the next gz* read, write, seek, or close operation, so gzdopen 1367 will not detect if fd is invalid (unless fd is -1). 1368 */ 1369 1370 ZEXTERN int ZEXPORT gzbuffer(gzFile file, unsigned size); 1371 /* 1372 Set the internal buffer size used by this library's functions for file to 1373 size. The default buffer size is 8192 bytes. This function must be called 1374 after gzopen() or gzdopen(), and before any other calls that read or write 1375 the file. The buffer memory allocation is always deferred to the first read 1376 or write. Three times that size in buffer space is allocated. A larger 1377 buffer size of, for example, 64K or 128K bytes will noticeably increase the 1378 speed of decompression (reading). 1379 1380 The new buffer size also affects the maximum length for gzprintf(). 1381 1382 gzbuffer() returns 0 on success, or -1 on failure, such as being called 1383 too late. 1384 */ 1385 1386 ZEXTERN int ZEXPORT gzsetparams(gzFile file, int level, int strategy); 1387 /* 1388 Dynamically update the compression level and strategy for file. See the 1389 description of deflateInit2 for the meaning of these parameters. Previously 1390 provided data is flushed before applying the parameter changes. 1391 1392 gzsetparams returns Z_OK if success, Z_STREAM_ERROR if the file was not 1393 opened for writing, Z_ERRNO if there is an error writing the flushed data, 1394 or Z_MEM_ERROR if there is a memory allocation error. 1395 */ 1396 1397 ZEXTERN int ZEXPORT gzread(gzFile file, voidp buf, unsigned len); 1398 /* 1399 Read and decompress up to len uncompressed bytes from file into buf. If 1400 the input file is not in gzip format, gzread copies the given number of 1401 bytes into the buffer directly from the file. 1402 1403 After reaching the end of a gzip stream in the input, gzread will continue 1404 to read, looking for another gzip stream. Any number of gzip streams may be 1405 concatenated in the input file, and will all be decompressed by gzread(). 1406 If something other than a gzip stream is encountered after a gzip stream, 1407 that remaining trailing garbage is ignored (and no error is returned). 1408 1409 gzread can be used to read a gzip file that is being concurrently written. 1410 Upon reaching the end of the input, gzread will return with the available 1411 data. If the error code returned by gzerror is Z_OK or Z_BUF_ERROR, then 1412 gzclearerr can be used to clear the end of file indicator in order to permit 1413 gzread to be tried again. Z_OK indicates that a gzip stream was completed 1414 on the last gzread. Z_BUF_ERROR indicates that the input file ended in the 1415 middle of a gzip stream. Note that gzread does not return -1 in the event 1416 of an incomplete gzip stream. This error is deferred until gzclose(), which 1417 will return Z_BUF_ERROR if the last gzread ended in the middle of a gzip 1418 stream. Alternatively, gzerror can be used before gzclose to detect this 1419 case. 1420 1421 gzread returns the number of uncompressed bytes actually read, less than 1422 len for end of file, or -1 for error. If len is too large to fit in an int, 1423 then nothing is read, -1 is returned, and the error state is set to 1424 Z_STREAM_ERROR. 1425 */ 1426 1427 ZEXTERN z_size_t ZEXPORT gzfread(voidp buf, z_size_t size, z_size_t nitems, 1428 gzFile file); 1429 /* 1430 Read and decompress up to nitems items of size size from file into buf, 1431 otherwise operating as gzread() does. This duplicates the interface of 1432 stdio's fread(), with size_t request and return types. If the library 1433 defines size_t, then z_size_t is identical to size_t. If not, then z_size_t 1434 is an unsigned integer type that can contain a pointer. 1435 1436 gzfread() returns the number of full items read of size size, or zero if 1437 the end of the file was reached and a full item could not be read, or if 1438 there was an error. gzerror() must be consulted if zero is returned in 1439 order to determine if there was an error. If the multiplication of size and 1440 nitems overflows, i.e. the product does not fit in a z_size_t, then nothing 1441 is read, zero is returned, and the error state is set to Z_STREAM_ERROR. 1442 1443 In the event that the end of file is reached and only a partial item is 1444 available at the end, i.e. the remaining uncompressed data length is not a 1445 multiple of size, then the final partial item is nevertheless read into buf 1446 and the end-of-file flag is set. The length of the partial item read is not 1447 provided, but could be inferred from the result of gztell(). This behavior 1448 is the same as the behavior of fread() implementations in common libraries, 1449 but it prevents the direct use of gzfread() to read a concurrently written 1450 file, resetting and retrying on end-of-file, when size is not 1. 1451 */ 1452 1453 ZEXTERN int ZEXPORT gzwrite(gzFile file, voidpc buf, unsigned len); 1454 /* 1455 Compress and write the len uncompressed bytes at buf to file. gzwrite 1456 returns the number of uncompressed bytes written or 0 in case of error. 1457 */ 1458 1459 ZEXTERN z_size_t ZEXPORT gzfwrite(voidpc buf, z_size_t size, 1460 z_size_t nitems, gzFile file); 1461 /* 1462 Compress and write nitems items of size size from buf to file, duplicating 1463 the interface of stdio's fwrite(), with size_t request and return types. If 1464 the library defines size_t, then z_size_t is identical to size_t. If not, 1465 then z_size_t is an unsigned integer type that can contain a pointer. 1466 1467 gzfwrite() returns the number of full items written of size size, or zero 1468 if there was an error. If the multiplication of size and nitems overflows, 1469 i.e. the product does not fit in a z_size_t, then nothing is written, zero 1470 is returned, and the error state is set to Z_STREAM_ERROR. 1471 */ 1472 1473 ZEXTERN int ZEXPORTVA gzprintf(gzFile file, const char *format, ...); 1474 /* 1475 Convert, format, compress, and write the arguments (...) to file under 1476 control of the string format, as in fprintf. gzprintf returns the number of 1477 uncompressed bytes actually written, or a negative zlib error code in case 1478 of error. The number of uncompressed bytes written is limited to 8191, or 1479 one less than the buffer size given to gzbuffer(). The caller should assure 1480 that this limit is not exceeded. If it is exceeded, then gzprintf() will 1481 return an error (0) with nothing written. In this case, there may also be a 1482 buffer overflow with unpredictable consequences, which is possible only if 1483 zlib was compiled with the insecure functions sprintf() or vsprintf(), 1484 because the secure snprintf() or vsnprintf() functions were not available. 1485 This can be determined using zlibCompileFlags(). 1486 */ 1487 1488 ZEXTERN int ZEXPORT gzputs(gzFile file, const char *s); 1489 /* 1490 Compress and write the given null-terminated string s to file, excluding 1491 the terminating null character. 1492 1493 gzputs returns the number of characters written, or -1 in case of error. 1494 */ 1495 1496 ZEXTERN char * ZEXPORT gzgets(gzFile file, char *buf, int len); 1497 /* 1498 Read and decompress bytes from file into buf, until len-1 characters are 1499 read, or until a newline character is read and transferred to buf, or an 1500 end-of-file condition is encountered. If any characters are read or if len 1501 is one, the string is terminated with a null character. If no characters 1502 are read due to an end-of-file or len is less than one, then the buffer is 1503 left untouched. 1504 1505 gzgets returns buf which is a null-terminated string, or it returns NULL 1506 for end-of-file or in case of error. If there was an error, the contents at 1507 buf are indeterminate. 1508 */ 1509 1510 ZEXTERN int ZEXPORT gzputc(gzFile file, int c); 1511 /* 1512 Compress and write c, converted to an unsigned char, into file. gzputc 1513 returns the value that was written, or -1 in case of error. 1514 */ 1515 1516 ZEXTERN int ZEXPORT gzgetc(gzFile file); 1517 /* 1518 Read and decompress one byte from file. gzgetc returns this byte or -1 1519 in case of end of file or error. This is implemented as a macro for speed. 1520 As such, it does not do all of the checking the other functions do. I.e. 1521 it does not check to see if file is NULL, nor whether the structure file 1522 points to has been clobbered or not. 1523 */ 1524 1525 ZEXTERN int ZEXPORT gzungetc(int c, gzFile file); 1526 /* 1527 Push c back onto the stream for file to be read as the first character on 1528 the next read. At least one character of push-back is always allowed. 1529 gzungetc() returns the character pushed, or -1 on failure. gzungetc() will 1530 fail if c is -1, and may fail if a character has been pushed but not read 1531 yet. If gzungetc is used immediately after gzopen or gzdopen, at least the 1532 output buffer size of pushed characters is allowed. (See gzbuffer above.) 1533 The pushed character will be discarded if the stream is repositioned with 1534 gzseek() or gzrewind(). 1535 */ 1536 1537 ZEXTERN int ZEXPORT gzflush(gzFile file, int flush); 1538 /* 1539 Flush all pending output to file. The parameter flush is as in the 1540 deflate() function. The return value is the zlib error number (see function 1541 gzerror below). gzflush is only permitted when writing. 1542 1543 If the flush parameter is Z_FINISH, the remaining data is written and the 1544 gzip stream is completed in the output. If gzwrite() is called again, a new 1545 gzip stream will be started in the output. gzread() is able to read such 1546 concatenated gzip streams. 1547 1548 gzflush should be called only when strictly necessary because it will 1549 degrade compression if called too often. 1550 */ 1551 1552 /* 1553 ZEXTERN z_off_t ZEXPORT gzseek(gzFile file, 1554 z_off_t offset, int whence); 1555 1556 Set the starting position to offset relative to whence for the next gzread 1557 or gzwrite on file. The offset represents a number of bytes in the 1558 uncompressed data stream. The whence parameter is defined as in lseek(2); 1559 the value SEEK_END is not supported. 1560 1561 If the file is opened for reading, this function is emulated but can be 1562 extremely slow. If the file is opened for writing, only forward seeks are 1563 supported; gzseek then compresses a sequence of zeroes up to the new 1564 starting position. 1565 1566 gzseek returns the resulting offset location as measured in bytes from 1567 the beginning of the uncompressed stream, or -1 in case of error, in 1568 particular if the file is opened for writing and the new starting position 1569 would be before the current position. 1570 */ 1571 1572 ZEXTERN int ZEXPORT gzrewind(gzFile file); 1573 /* 1574 Rewind file. This function is supported only for reading. 1575 1576 gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET). 1577 */ 1578 1579 /* 1580 ZEXTERN z_off_t ZEXPORT gztell(gzFile file); 1581 1582 Return the starting position for the next gzread or gzwrite on file. 1583 This position represents a number of bytes in the uncompressed data stream, 1584 and is zero when starting, even if appending or reading a gzip stream from 1585 the middle of a file using gzdopen(). 1586 1587 gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR) 1588 */ 1589 1590 /* 1591 ZEXTERN z_off_t ZEXPORT gzoffset(gzFile file); 1592 1593 Return the current compressed (actual) read or write offset of file. This 1594 offset includes the count of bytes that precede the gzip stream, for example 1595 when appending or when using gzdopen() for reading. When reading, the 1596 offset does not include as yet unused buffered input. This information can 1597 be used for a progress indicator. On error, gzoffset() returns -1. 1598 */ 1599 1600 ZEXTERN int ZEXPORT gzeof(gzFile file); 1601 /* 1602 Return true (1) if the end-of-file indicator for file has been set while 1603 reading, false (0) otherwise. Note that the end-of-file indicator is set 1604 only if the read tried to go past the end of the input, but came up short. 1605 Therefore, just like feof(), gzeof() may return false even if there is no 1606 more data to read, in the event that the last read request was for the exact 1607 number of bytes remaining in the input file. This will happen if the input 1608 file size is an exact multiple of the buffer size. 1609 1610 If gzeof() returns true, then the read functions will return no more data, 1611 unless the end-of-file indicator is reset by gzclearerr() and the input file 1612 has grown since the previous end of file was detected. 1613 */ 1614 1615 ZEXTERN int ZEXPORT gzdirect(gzFile file); 1616 /* 1617 Return true (1) if file is being copied directly while reading, or false 1618 (0) if file is a gzip stream being decompressed. 1619 1620 If the input file is empty, gzdirect() will return true, since the input 1621 does not contain a gzip stream. 1622 1623 If gzdirect() is used immediately after gzopen() or gzdopen() it will 1624 cause buffers to be allocated to allow reading the file to determine if it 1625 is a gzip file. Therefore if gzbuffer() is used, it should be called before 1626 gzdirect(). 1627 1628 When writing, gzdirect() returns true (1) if transparent writing was 1629 requested ("wT" for the gzopen() mode), or false (0) otherwise. (Note: 1630 gzdirect() is not needed when writing. Transparent writing must be 1631 explicitly requested, so the application already knows the answer. When 1632 linking statically, using gzdirect() will include all of the zlib code for 1633 gzip file reading and decompression, which may not be desired.) 1634 */ 1635 1636 ZEXTERN int ZEXPORT gzclose(gzFile file); 1637 /* 1638 Flush all pending output for file, if necessary, close file and 1639 deallocate the (de)compression state. Note that once file is closed, you 1640 cannot call gzerror with file, since its structures have been deallocated. 1641 gzclose must not be called more than once on the same file, just as free 1642 must not be called more than once on the same allocation. 1643 1644 gzclose will return Z_STREAM_ERROR if file is not valid, Z_ERRNO on a 1645 file operation error, Z_MEM_ERROR if out of memory, Z_BUF_ERROR if the 1646 last read ended in the middle of a gzip stream, or Z_OK on success. 1647 */ 1648 1649 ZEXTERN int ZEXPORT gzclose_r(gzFile file); 1650 ZEXTERN int ZEXPORT gzclose_w(gzFile file); 1651 /* 1652 Same as gzclose(), but gzclose_r() is only for use when reading, and 1653 gzclose_w() is only for use when writing or appending. The advantage to 1654 using these instead of gzclose() is that they avoid linking in zlib 1655 compression or decompression code that is not used when only reading or only 1656 writing respectively. If gzclose() is used, then both compression and 1657 decompression code will be included the application when linking to a static 1658 zlib library. 1659 */ 1660 1661 ZEXTERN const char * ZEXPORT gzerror(gzFile file, int *errnum); 1662 /* 1663 Return the error message for the last error which occurred on file. 1664 errnum is set to zlib error number. If an error occurred in the file system 1665 and not in the compression library, errnum is set to Z_ERRNO and the 1666 application may consult errno to get the exact error code. 1667 1668 The application must not modify the returned string. Future calls to 1669 this function may invalidate the previously returned string. If file is 1670 closed, then the string previously returned by gzerror will no longer be 1671 available. 1672 1673 gzerror() should be used to distinguish errors from end-of-file for those 1674 functions above that do not distinguish those cases in their return values. 1675 */ 1676 1677 ZEXTERN void ZEXPORT gzclearerr(gzFile file); 1678 /* 1679 Clear the error and end-of-file flags for file. This is analogous to the 1680 clearerr() function in stdio. This is useful for continuing to read a gzip 1681 file that is being written concurrently. 1682 */ 1683 1684 #endif /* !Z_SOLO */ 1685 1686 /* checksum functions */ 1687 1688 /* 1689 These functions are not related to compression but are exported 1690 anyway because they might be useful in applications using the compression 1691 library. 1692 */ 1693 1694 ZEXTERN uLong ZEXPORT adler32(uLong adler, const Bytef *buf, uInt len); 1695 /* 1696 Update a running Adler-32 checksum with the bytes buf[0..len-1] and 1697 return the updated checksum. An Adler-32 value is in the range of a 32-bit 1698 unsigned integer. If buf is Z_NULL, this function returns the required 1699 initial value for the checksum. 1700 1701 An Adler-32 checksum is almost as reliable as a CRC-32 but can be computed 1702 much faster. 1703 1704 Usage example: 1705 1706 uLong adler = adler32(0L, Z_NULL, 0); 1707 1708 while (read_buffer(buffer, length) != EOF) { 1709 adler = adler32(adler, buffer, length); 1710 } 1711 if (adler != original_adler) error(); 1712 */ 1713 1714 ZEXTERN uLong ZEXPORT adler32_z(uLong adler, const Bytef *buf, 1715 z_size_t len); 1716 /* 1717 Same as adler32(), but with a size_t length. 1718 */ 1719 1720 /* 1721 ZEXTERN uLong ZEXPORT adler32_combine(uLong adler1, uLong adler2, 1722 z_off_t len2); 1723 1724 Combine two Adler-32 checksums into one. For two sequences of bytes, seq1 1725 and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for 1726 each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of 1727 seq1 and seq2 concatenated, requiring only adler1, adler2, and len2. Note 1728 that the z_off_t type (like off_t) is a signed integer. If len2 is 1729 negative, the result has no meaning or utility. 1730 */ 1731 1732 #if !defined(_KERNEL) && !defined(_STANDALONE) 1733 ZEXTERN uLong ZEXPORT crc32(uLong crc, const Bytef *buf, uInt len); 1734 #endif 1735 /* 1736 Update a running CRC-32 with the bytes buf[0..len-1] and return the 1737 updated CRC-32. A CRC-32 value is in the range of a 32-bit unsigned integer. 1738 If buf is Z_NULL, this function returns the required initial value for the 1739 crc. Pre- and post-conditioning (one's complement) is performed within this 1740 function so it shouldn't be done by the application. 1741 1742 Usage example: 1743 1744 uLong crc = crc32(0L, Z_NULL, 0); 1745 1746 while (read_buffer(buffer, length) != EOF) { 1747 crc = crc32(crc, buffer, length); 1748 } 1749 if (crc != original_crc) error(); 1750 */ 1751 1752 ZEXTERN uLong ZEXPORT crc32_z(uLong crc, const Bytef *buf, 1753 z_size_t len); 1754 /* 1755 Same as crc32(), but with a size_t length. 1756 */ 1757 1758 /* 1759 ZEXTERN uLong ZEXPORT crc32_combine(uLong crc1, uLong crc2, z_off_t len2); 1760 1761 Combine two CRC-32 check values into one. For two sequences of bytes, 1762 seq1 and seq2 with lengths len1 and len2, CRC-32 check values were 1763 calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32 1764 check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and 1765 len2. len2 must be non-negative. 1766 */ 1767 1768 /* 1769 ZEXTERN uLong ZEXPORT crc32_combine_gen(z_off_t len2); 1770 1771 Return the operator corresponding to length len2, to be used with 1772 crc32_combine_op(). len2 must be non-negative. 1773 */ 1774 1775 ZEXTERN uLong ZEXPORT crc32_combine_op(uLong crc1, uLong crc2, uLong op); 1776 /* 1777 Give the same result as crc32_combine(), using op in place of len2. op is 1778 is generated from len2 by crc32_combine_gen(). This will be faster than 1779 crc32_combine() if the generated op is used more than once. 1780 */ 1781 1782 1783 /* various hacks, don't look :) */ 1784 1785 /* deflateInit and inflateInit are macros to allow checking the zlib version 1786 * and the compiler's view of z_stream: 1787 */ 1788 ZEXTERN int ZEXPORT deflateInit_(z_streamp strm, int level, 1789 const char *version, int stream_size); 1790 ZEXTERN int ZEXPORT inflateInit_(z_streamp strm, 1791 const char *version, int stream_size); 1792 ZEXTERN int ZEXPORT deflateInit2_(z_streamp strm, int level, int method, 1793 int windowBits, int memLevel, 1794 int strategy, const char *version, 1795 int stream_size); 1796 ZEXTERN int ZEXPORT inflateInit2_(z_streamp strm, int windowBits, 1797 const char *version, int stream_size); 1798 ZEXTERN int ZEXPORT inflateBackInit_(z_streamp strm, int windowBits, 1799 unsigned char FAR *window, 1800 const char *version, 1801 int stream_size); 1802 #ifdef Z_PREFIX_SET 1803 # define z_deflateInit(strm, level) \ 1804 deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream)) 1805 # define z_inflateInit(strm) \ 1806 inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream)) 1807 # define z_deflateInit2(strm, level, method, windowBits, memLevel, strategy) \ 1808 deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\ 1809 (strategy), ZLIB_VERSION, (int)sizeof(z_stream)) 1810 # define z_inflateInit2(strm, windowBits) \ 1811 inflateInit2_((strm), (windowBits), ZLIB_VERSION, \ 1812 (int)sizeof(z_stream)) 1813 # define z_inflateBackInit(strm, windowBits, window) \ 1814 inflateBackInit_((strm), (windowBits), (window), \ 1815 ZLIB_VERSION, (int)sizeof(z_stream)) 1816 #else 1817 # define deflateInit(strm, level) \ 1818 deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream)) 1819 # define inflateInit(strm) \ 1820 inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream)) 1821 # define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \ 1822 deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\ 1823 (strategy), ZLIB_VERSION, (int)sizeof(z_stream)) 1824 # define inflateInit2(strm, windowBits) \ 1825 inflateInit2_((strm), (windowBits), ZLIB_VERSION, \ 1826 (int)sizeof(z_stream)) 1827 # define inflateBackInit(strm, windowBits, window) \ 1828 inflateBackInit_((strm), (windowBits), (window), \ 1829 ZLIB_VERSION, (int)sizeof(z_stream)) 1830 #endif 1831 1832 #ifndef Z_SOLO 1833 1834 /* gzgetc() macro and its supporting function and exposed data structure. Note 1835 * that the real internal state is much larger than the exposed structure. 1836 * This abbreviated structure exposes just enough for the gzgetc() macro. The 1837 * user should not mess with these exposed elements, since their names or 1838 * behavior could change in the future, perhaps even capriciously. They can 1839 * only be used by the gzgetc() macro. You have been warned. 1840 */ 1841 struct gzFile_s { 1842 unsigned have; 1843 unsigned char *next; 1844 z_off64_t pos; 1845 }; 1846 ZEXTERN int ZEXPORT gzgetc_(gzFile file); /* backward compatibility */ 1847 #ifdef Z_PREFIX_SET 1848 # undef z_gzgetc 1849 # define z_gzgetc(g) \ 1850 ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : (gzgetc)(g)) 1851 #else 1852 # define gzgetc(g) \ 1853 ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : (gzgetc)(g)) 1854 #endif 1855 1856 /* provide 64-bit offset functions if _LARGEFILE64_SOURCE defined, and/or 1857 * change the regular functions to 64 bits if _FILE_OFFSET_BITS is 64 (if 1858 * both are true, the application gets the *64 functions, and the regular 1859 * functions are changed to 64 bits) -- in case these are set on systems 1860 * without large file support, _LFS64_LARGEFILE must also be true 1861 */ 1862 #ifdef Z_LARGE64 1863 ZEXTERN gzFile ZEXPORT gzopen64(const char *, const char *); 1864 ZEXTERN z_off64_t ZEXPORT gzseek64(gzFile, z_off64_t, int); 1865 ZEXTERN z_off64_t ZEXPORT gztell64(gzFile); 1866 ZEXTERN z_off64_t ZEXPORT gzoffset64(gzFile); 1867 ZEXTERN uLong ZEXPORT adler32_combine64(uLong, uLong, z_off64_t); 1868 ZEXTERN uLong ZEXPORT crc32_combine64(uLong, uLong, z_off64_t); 1869 ZEXTERN uLong ZEXPORT crc32_combine_gen64(z_off64_t); 1870 #endif 1871 1872 #if !defined(ZLIB_INTERNAL) && defined(Z_WANT64) 1873 # ifdef Z_PREFIX_SET 1874 # define z_gzopen z_gzopen64 1875 # define z_gzseek z_gzseek64 1876 # define z_gztell z_gztell64 1877 # define z_gzoffset z_gzoffset64 1878 # define z_adler32_combine z_adler32_combine64 1879 # define z_crc32_combine z_crc32_combine64 1880 # define z_crc32_combine_gen z_crc32_combine_gen64 1881 # else 1882 # define gzopen gzopen64 1883 # define gzseek gzseek64 1884 # define gztell gztell64 1885 # define gzoffset gzoffset64 1886 # define adler32_combine adler32_combine64 1887 # define crc32_combine crc32_combine64 1888 # define crc32_combine_gen crc32_combine_gen64 1889 # endif 1890 # ifndef Z_LARGE64 1891 ZEXTERN gzFile ZEXPORT gzopen64(const char *, const char *); 1892 ZEXTERN z_off_t ZEXPORT gzseek64(gzFile, z_off_t, int); 1893 ZEXTERN z_off_t ZEXPORT gztell64(gzFile); 1894 ZEXTERN z_off_t ZEXPORT gzoffset64(gzFile); 1895 ZEXTERN uLong ZEXPORT adler32_combine64(uLong, uLong, z_off_t); 1896 ZEXTERN uLong ZEXPORT crc32_combine64(uLong, uLong, z_off_t); 1897 ZEXTERN uLong ZEXPORT crc32_combine_gen64(z_off_t); 1898 # endif 1899 #else 1900 ZEXTERN gzFile ZEXPORT gzopen(const char *, const char *); 1901 ZEXTERN z_off_t ZEXPORT gzseek(gzFile, z_off_t, int); 1902 ZEXTERN z_off_t ZEXPORT gztell(gzFile); 1903 ZEXTERN z_off_t ZEXPORT gzoffset(gzFile); 1904 ZEXTERN uLong ZEXPORT adler32_combine(uLong, uLong, z_off_t); 1905 ZEXTERN uLong ZEXPORT crc32_combine(uLong, uLong, z_off_t); 1906 ZEXTERN uLong ZEXPORT crc32_combine_gen(z_off_t); 1907 #endif 1908 1909 #else /* Z_SOLO */ 1910 1911 ZEXTERN uLong ZEXPORT adler32_combine(uLong, uLong, z_off_t); 1912 ZEXTERN uLong ZEXPORT crc32_combine(uLong, uLong, z_off_t); 1913 ZEXTERN uLong ZEXPORT crc32_combine_gen(z_off_t); 1914 1915 #endif /* !Z_SOLO */ 1916 1917 /* undocumented functions */ 1918 ZEXTERN const char * ZEXPORT zError(int); 1919 ZEXTERN int ZEXPORT inflateSyncPoint(z_streamp); 1920 ZEXTERN const z_crc_t FAR * ZEXPORT get_crc_table(void); 1921 ZEXTERN int ZEXPORT inflateUndermine(z_streamp, int); 1922 ZEXTERN int ZEXPORT inflateValidate(z_streamp, int); 1923 ZEXTERN unsigned long ZEXPORT inflateCodesUsed(z_streamp); 1924 ZEXTERN int ZEXPORT inflateResetKeep(z_streamp); 1925 ZEXTERN int ZEXPORT deflateResetKeep(z_streamp); 1926 #if defined(_WIN32) && !defined(Z_SOLO) 1927 ZEXTERN gzFile ZEXPORT gzopen_w(const wchar_t *path, 1928 const char *mode); 1929 #endif 1930 #if defined(STDC) || defined(Z_HAVE_STDARG_H) 1931 # ifndef Z_SOLO 1932 ZEXTERN int ZEXPORTVA gzvprintf(gzFile file, 1933 const char *format, 1934 va_list va); 1935 # endif 1936 #endif 1937 1938 #ifdef __cplusplus 1939 } 1940 #endif 1941 1942 #endif /* ZLIB_H */ 1943
Indexes created Sat Sep 20 22:09:52 GMT 2025