1 /* zlib.h -- interface of the 'zlib' general purpose compression library 2 version 1.3.1.1, January xxth, 2024 3 4 Copyright (C) 1995-2024 Jean-loup Gailly and Mark Adler 5 6 This software is provided 'as-is', without any express or implied 7 warranty. In no event will the authors be held liable for any damages 8 arising from the use of this software. 9 10 Permission is granted to anyone to use this software for any purpose, 11 including commercial applications, and to alter it and redistribute it 12 freely, subject to the following restrictions: 13 14 1. The origin of this software must not be misrepresented; you must not 15 claim that you wrote the original software. If you use this software 16 in a product, an acknowledgment in the product documentation would be 17 appreciated but is not required. 18 2. Altered source versions must be plainly marked as such, and must not be 19 misrepresented as being the original software. 20 3. This notice may not be removed or altered from any source distribution. 21 22 Jean-loup Gailly Mark Adler 23 jloup@gzip.org madler@alumni.caltech.edu 24 25 26 The data format used by the zlib library is described by RFCs (Request for 27 Comments) 1950 to 1952 in the files http://tools.ietf.org/html/rfc1950 28 (zlib format), rfc1951 (deflate format) and rfc1952 (gzip format). 29 */ 30 31 #ifndef ZLIB_H 32 #define ZLIB_H 33 34 #ifdef ZLIB_BUILD 35 # include <zconf.h> 36 #else 37 # include "zconf.h" 38 #endif 39 40 #ifdef __cplusplus 41 extern "C" { 42 #endif 43 44 #define ZLIB_VERSION "1.3.1.1-motley" 45 #define ZLIB_VERNUM 0x1311 46 #define ZLIB_VER_MAJOR 1 47 #define ZLIB_VER_MINOR 3 48 #define ZLIB_VER_REVISION 1 49 #define ZLIB_VER_SUBREVISION 1 50 51 /* 52 The 'zlib' compression library provides in-memory compression and 53 decompression functions, including integrity checks of the uncompressed data. 54 This version of the library supports only one compression method (deflation) 55 but other algorithms will be added later and will have the same stream 56 interface. 57 58 Compression can be done in a single step if the buffers are large enough, 59 or can be done by repeated calls of the compression function. In the latter 60 case, the application must provide more input and/or consume the output 61 (providing more output space) before each call. 62 63 The compressed data format used by default by the in-memory functions is 64 the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped 65 around a deflate stream, which is itself documented in RFC 1951. 66 67 The library also supports reading and writing files in gzip (.gz) format 68 with an interface similar to that of stdio using the functions that start 69 with "gz". The gzip format is different from the zlib format. gzip is a 70 gzip wrapper, documented in RFC 1952, wrapped around a deflate stream. 71 72 This library can optionally read and write gzip and raw deflate streams in 73 memory as well. 74 75 The zlib format was designed to be compact and fast for use in memory 76 and on communications channels. The gzip format was designed for single- 77 file compression on file systems, has a larger header than zlib to maintain 78 directory information, and uses a different, slower check method than zlib. 79 80 The library does not install any signal handler. The decoder checks 81 the consistency of the compressed data, so the library should never crash 82 even in the case of corrupted input. 83 */ 84 85 typedef voidpf (*alloc_func)(voidpf opaque, uInt items, uInt size); 86 typedef void (*free_func)(voidpf opaque, voidpf address); 87 88 struct internal_state; 89 90 typedef struct z_stream_s { 91 z_const Bytef *next_in; /* next input byte */ 92 uInt avail_in; /* number of bytes available at next_in */ 93 uLong total_in; /* total number of input bytes read so far */ 94 95 Bytef *next_out; /* next output byte will go here */ 96 uInt avail_out; /* remaining free space at next_out */ 97 uLong total_out; /* total number of bytes output so far */ 98 99 z_const char *msg; /* last error message, NULL if no error */ 100 struct internal_state FAR *state; /* not visible by applications */ 101 102 alloc_func zalloc; /* used to allocate the internal state */ 103 free_func zfree; /* used to free the internal state */ 104 voidpf opaque; /* private data object passed to zalloc and zfree */ 105 106 int data_type; /* best guess about the data type: binary or text 107 for deflate, or the decoding state for inflate */ 108 uLong adler; /* Adler-32 or CRC-32 value of the uncompressed data */ 109 uLong reserved; /* reserved for future use */ 110 } z_stream; 111 112 typedef z_stream FAR *z_streamp; 113 114 /* 115 gzip header information passed to and from zlib routines. See RFC 1952 116 for more details on the meanings of these fields. 117 */ 118 typedef struct gz_header_s { 119 int text; /* true if compressed data believed to be text */ 120 uLong time; /* modification time */ 121 int xflags; /* extra flags (not used when writing a gzip file) */ 122 int os; /* operating system */ 123 Bytef *extra; /* pointer to extra field or Z_NULL if none */ 124 uInt extra_len; /* extra field length (valid if extra != Z_NULL) */ 125 uInt extra_max; /* space at extra (only when reading header) */ 126 Bytef *name; /* pointer to zero-terminated file name or Z_NULL */ 127 uInt name_max; /* space at name (only when reading header) */ 128 Bytef *comment; /* pointer to zero-terminated comment or Z_NULL */ 129 uInt comm_max; /* space at comment (only when reading header) */ 130 int hcrc; /* true if there was or will be a header crc */ 131 int done; /* true when done reading gzip header (not used 132 when writing a gzip file) */ 133 } gz_header; 134 135 typedef gz_header FAR *gz_headerp; 136 137 /* 138 The application must update next_in and avail_in when avail_in has dropped 139 to zero. It must update next_out and avail_out when avail_out has dropped 140 to zero. The application must initialize zalloc, zfree and opaque before 141 calling the init function. All other fields are set by the compression 142 library and must not be updated by the application. 143 144 The opaque value provided by the application will be passed as the first 145 parameter for calls of zalloc and zfree. This can be useful for custom 146 memory management. The compression library attaches no meaning to the 147 opaque value. 148 149 zalloc must return Z_NULL if there is not enough memory for the object. 150 If zlib is used in a multi-threaded application, zalloc and zfree must be 151 thread safe. In that case, zlib is thread-safe. When zalloc and zfree are 152 Z_NULL on entry to the initialization function, they are set to internal 153 routines that use the standard library functions malloc() and free(). 154 155 On 16-bit systems, the functions zalloc and zfree must be able to allocate 156 exactly 65536 bytes, but will not be required to allocate more than this if 157 the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, pointers 158 returned by zalloc for objects of exactly 65536 bytes *must* have their 159 offset normalized to zero. The default allocation function provided by this 160 library ensures this (see zutil.c). To reduce memory requirements and avoid 161 any allocation of 64K objects, at the expense of compression ratio, compile 162 the library with -DMAX_WBITS=14 (see zconf.h). 163 164 The fields total_in and total_out can be used for statistics or progress 165 reports. After compression, total_in holds the total size of the 166 uncompressed data and may be saved for use by the decompressor (particularly 167 if the decompressor wants to decompress everything in a single step). 168 */ 169 170 /* constants */ 171 172 #define Z_NO_FLUSH 0 173 #define Z_PARTIAL_FLUSH 1 174 #define Z_SYNC_FLUSH 2 175 #define Z_FULL_FLUSH 3 176 #define Z_FINISH 4 177 #define Z_BLOCK 5 178 #define Z_TREES 6 179 /* Allowed flush values; see deflate() and inflate() below for details */ 180 181 #define Z_OK 0 182 #define Z_STREAM_END 1 183 #define Z_NEED_DICT 2 184 #define Z_ERRNO (-1) 185 #define Z_STREAM_ERROR (-2) 186 #define Z_DATA_ERROR (-3) 187 #define Z_MEM_ERROR (-4) 188 #define Z_BUF_ERROR (-5) 189 #define Z_VERSION_ERROR (-6) 190 /* Return codes for the compression/decompression functions. Negative values 191 * are errors, positive values are used for special but normal events. 192 */ 193 194 #define Z_NO_COMPRESSION 0 195 #define Z_BEST_SPEED 1 196 #define Z_BEST_COMPRESSION 9 197 #define Z_DEFAULT_COMPRESSION (-1) 198 /* compression levels */ 199 200 #define Z_FILTERED 1 201 #define Z_HUFFMAN_ONLY 2 202 #define Z_RLE 3 203 #define Z_FIXED 4 204 #define Z_DEFAULT_STRATEGY 0 205 /* compression strategy; see deflateInit2() below for details */ 206 207 #define Z_BINARY 0 208 #define Z_TEXT 1 209 #define Z_ASCII Z_TEXT /* for compatibility with 1.2.2 and earlier */ 210 #define Z_UNKNOWN 2 211 /* Possible values of the data_type field for deflate() */ 212 213 #define Z_DEFLATED 8 214 /* The deflate compression method (the only one supported in this version) */ 215 216 #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */ 217 218 #define zlib_version zlibVersion() 219 /* for compatibility with versions < 1.0.2 */ 220 221 222 /* basic functions */ 223 224 ZEXTERN const char * ZEXPORT zlibVersion(void); 225 /* The application can compare zlibVersion and ZLIB_VERSION for consistency. 226 If the first character differs, the library code actually used is not 227 compatible with the zlib.h header file used by the application. This check 228 is automatically made by deflateInit and inflateInit. 229 */ 230 231 /* 232 ZEXTERN int ZEXPORT deflateInit(z_streamp strm, int level); 233 234 Initializes the internal stream state for compression. The fields 235 zalloc, zfree and opaque must be initialized before by the caller. If 236 zalloc and zfree are set to Z_NULL, deflateInit updates them to use default 237 allocation functions. total_in, total_out, adler, and msg are initialized. 238 239 The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9: 240 1 gives best speed, 9 gives best compression, 0 gives no compression at all 241 (the input data is simply copied a block at a time). Z_DEFAULT_COMPRESSION 242 requests a default compromise between speed and compression (currently 243 equivalent to level 6). 244 245 deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough 246 memory, Z_STREAM_ERROR if level is not a valid compression level, or 247 Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible 248 with the version assumed by the caller (ZLIB_VERSION). msg is set to null 249 if there is no error message. deflateInit does not perform any compression: 250 this will be done by deflate(). 251 */ 252 253 254 ZEXTERN int ZEXPORT deflate(z_streamp strm, int flush); 255 /* 256 deflate compresses as much data as possible, and stops when the input 257 buffer becomes empty or the output buffer becomes full. It may introduce 258 some output latency (reading input without producing any output) except when 259 forced to flush. 260 261 The detailed semantics are as follows. deflate performs one or both of the 262 following actions: 263 264 - Compress more input starting at next_in and update next_in and avail_in 265 accordingly. If not all input can be processed (because there is not 266 enough room in the output buffer), next_in and avail_in are updated and 267 processing will resume at this point for the next call of deflate(). 268 269 - Generate more output starting at next_out and update next_out and avail_out 270 accordingly. This action is forced if the parameter flush is non zero. 271 Forcing flush frequently degrades the compression ratio, so this parameter 272 should be set only when necessary. Some output may be provided even if 273 flush is zero. 274 275 Before the call of deflate(), the application should ensure that at least 276 one of the actions is possible, by providing more input and/or consuming more 277 output, and updating avail_in or avail_out accordingly; avail_out should 278 never be zero before the call. The application can consume the compressed 279 output when it wants, for example when the output buffer is full (avail_out 280 == 0), or after each call of deflate(). If deflate returns Z_OK and with 281 zero avail_out, it must be called again after making room in the output 282 buffer because there might be more output pending. See deflatePending(), 283 which can be used if desired to determine whether or not there is more output 284 in that case. 285 286 Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to 287 decide how much data to accumulate before producing output, in order to 288 maximize compression. 289 290 If the parameter flush is set to Z_SYNC_FLUSH, all pending output is 291 flushed to the output buffer and the output is aligned on a byte boundary, so 292 that the decompressor can get all input data available so far. (In 293 particular avail_in is zero after the call if enough output space has been 294 provided before the call.) Flushing may degrade compression for some 295 compression algorithms and so it should be used only when necessary. This 296 completes the current deflate block and follows it with an empty stored block 297 that is three bits plus filler bits to the next byte, followed by four bytes 298 (00 00 ff ff). 299 300 If flush is set to Z_PARTIAL_FLUSH, all pending output is flushed to the 301 output buffer, but the output is not aligned to a byte boundary. All of the 302 input data so far will be available to the decompressor, as for Z_SYNC_FLUSH. 303 This completes the current deflate block and follows it with an empty fixed 304 codes block that is 10 bits long. This assures that enough bytes are output 305 in order for the decompressor to finish the block before the empty fixed 306 codes block. 307 308 If flush is set to Z_BLOCK, a deflate block is completed and emitted, as 309 for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to 310 seven bits of the current block are held to be written as the next byte after 311 the next deflate block is completed. In this case, the decompressor may not 312 be provided enough bits at this point in order to complete decompression of 313 the data provided so far to the compressor. It may need to wait for the next 314 block to be emitted. This is for advanced applications that need to control 315 the emission of deflate blocks. 316 317 If flush is set to Z_FULL_FLUSH, all output is flushed as with 318 Z_SYNC_FLUSH, and the compression state is reset so that decompression can 319 restart from this point if previous compressed data has been damaged or if 320 random access is desired. Using Z_FULL_FLUSH too often can seriously degrade 321 compression. 322 323 If deflate returns with avail_out == 0, this function must be called again 324 with the same value of the flush parameter and more output space (updated 325 avail_out), until the flush is complete (deflate returns with non-zero 326 avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that 327 avail_out is greater than six when the flush marker begins, in order to avoid 328 repeated flush markers upon calling deflate() again when avail_out == 0. 329 330 If the parameter flush is set to Z_FINISH, pending input is processed, 331 pending output is flushed and deflate returns with Z_STREAM_END if there was 332 enough output space. If deflate returns with Z_OK or Z_BUF_ERROR, this 333 function must be called again with Z_FINISH and more output space (updated 334 avail_out) but no more input data, until it returns with Z_STREAM_END or an 335 error. After deflate has returned Z_STREAM_END, the only possible operations 336 on the stream are deflateReset or deflateEnd. 337 338 Z_FINISH can be used in the first deflate call after deflateInit if all the 339 compression is to be done in a single step. In order to complete in one 340 call, avail_out must be at least the value returned by deflateBound (see 341 below). Then deflate is guaranteed to return Z_STREAM_END. If not enough 342 output space is provided, deflate will not return Z_STREAM_END, and it must 343 be called again as described above. 344 345 deflate() sets strm->adler to the Adler-32 checksum of all input read 346 so far (that is, total_in bytes). If a gzip stream is being generated, then 347 strm->adler will be the CRC-32 checksum of the input read so far. (See 348 deflateInit2 below.) 349 350 deflate() may update strm->data_type if it can make a good guess about 351 the input data type (Z_BINARY or Z_TEXT). If in doubt, the data is 352 considered binary. This field is only for information purposes and does not 353 affect the compression algorithm in any manner. 354 355 deflate() returns Z_OK if some progress has been made (more input 356 processed or more output produced), Z_STREAM_END if all input has been 357 consumed and all output has been produced (only when flush is set to 358 Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example 359 if next_in or next_out was Z_NULL or the state was inadvertently written over 360 by the application), or Z_BUF_ERROR if no progress is possible (for example 361 avail_in or avail_out was zero). Note that Z_BUF_ERROR is not fatal, and 362 deflate() can be called again with more input and more output space to 363 continue compressing. 364 */ 365 366 367 ZEXTERN int ZEXPORT deflateEnd(z_streamp strm); 368 /* 369 All dynamically allocated data structures for this stream are freed. 370 This function discards any unprocessed input and does not flush any pending 371 output. 372 373 deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the 374 stream state was inconsistent, Z_DATA_ERROR if the stream was freed 375 prematurely (some input or output was discarded). In the error case, msg 376 may be set but then points to a static string (which must not be 377 deallocated). 378 */ 379 380 381 /* 382 ZEXTERN int ZEXPORT inflateInit(z_streamp strm); 383 384 Initializes the internal stream state for decompression. The fields 385 next_in, avail_in, zalloc, zfree and opaque must be initialized before by 386 the caller. In the current version of inflate, the provided input is not 387 read or consumed. The allocation of a sliding window will be deferred to 388 the first call of inflate (if the decompression does not complete on the 389 first call). If zalloc and zfree are set to Z_NULL, inflateInit updates 390 them to use default allocation functions. total_in, total_out, adler, and 391 msg are initialized. 392 393 inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough 394 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the 395 version assumed by the caller, or Z_STREAM_ERROR if the parameters are 396 invalid, such as a null pointer to the structure. msg is set to null if 397 there is no error message. inflateInit does not perform any decompression. 398 Actual decompression will be done by inflate(). So next_in, and avail_in, 399 next_out, and avail_out are unused and unchanged. The current 400 implementation of inflateInit() does not process any header information -- 401 that is deferred until inflate() is called. 402 */ 403 404 405 ZEXTERN int ZEXPORT inflate(z_streamp strm, int flush); 406 /* 407 inflate decompresses as much data as possible, and stops when the input 408 buffer becomes empty or the output buffer becomes full. It may introduce 409 some output latency (reading input without producing any output) except when 410 forced to flush. 411 412 The detailed semantics are as follows. inflate performs one or both of the 413 following actions: 414 415 - Decompress more input starting at next_in and update next_in and avail_in 416 accordingly. If not all input can be processed (because there is not 417 enough room in the output buffer), then next_in and avail_in are updated 418 accordingly, and processing will resume at this point for the next call of 419 inflate(). 420 421 - Generate more output starting at next_out and update next_out and avail_out 422 accordingly. inflate() provides as much output as possible, until there is 423 no more input data or no more space in the output buffer (see below about 424 the flush parameter). 425 426 Before the call of inflate(), the application should ensure that at least 427 one of the actions is possible, by providing more input and/or consuming more 428 output, and updating the next_* and avail_* values accordingly. If the 429 caller of inflate() does not provide both available input and available 430 output space, it is possible that there will be no progress made. The 431 application can consume the uncompressed output when it wants, for example 432 when the output buffer is full (avail_out == 0), or after each call of 433 inflate(). If inflate returns Z_OK and with zero avail_out, it must be 434 called again after making room in the output buffer because there might be 435 more output pending. 436 437 The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, Z_FINISH, 438 Z_BLOCK, or Z_TREES. Z_SYNC_FLUSH requests that inflate() flush as much 439 output as possible to the output buffer. Z_BLOCK requests that inflate() 440 stop if and when it gets to the next deflate block boundary. When decoding 441 the zlib or gzip format, this will cause inflate() to return immediately 442 after the header and before the first block. When doing a raw inflate, 443 inflate() will go ahead and process the first block, and will return when it 444 gets to the end of that block, or when it runs out of data. 445 446 The Z_BLOCK option assists in appending to or combining deflate streams. 447 To assist in this, on return inflate() always sets strm->data_type to the 448 number of unused bits in the last byte taken from strm->next_in, plus 64 if 449 inflate() is currently decoding the last block in the deflate stream, plus 450 128 if inflate() returned immediately after decoding an end-of-block code or 451 decoding the complete header up to just before the first byte of the deflate 452 stream. The end-of-block will not be indicated until all of the uncompressed 453 data from that block has been written to strm->next_out. The number of 454 unused bits may in general be greater than seven, except when bit 7 of 455 data_type is set, in which case the number of unused bits will be less than 456 eight. data_type is set as noted here every time inflate() returns for all 457 flush options, and so can be used to determine the amount of currently 458 consumed input in bits. 459 460 The Z_TREES option behaves as Z_BLOCK does, but it also returns when the 461 end of each deflate block header is reached, before any actual data in that 462 block is decoded. This allows the caller to determine the length of the 463 deflate block header for later use in random access within a deflate block. 464 256 is added to the value of strm->data_type when inflate() returns 465 immediately after reaching the end of the deflate block header. 466 467 inflate() should normally be called until it returns Z_STREAM_END or an 468 error. However if all decompression is to be performed in a single step (a 469 single call of inflate), the parameter flush should be set to Z_FINISH. In 470 this case all pending input is processed and all pending output is flushed; 471 avail_out must be large enough to hold all of the uncompressed data for the 472 operation to complete. (The size of the uncompressed data may have been 473 saved by the compressor for this purpose.) The use of Z_FINISH is not 474 required to perform an inflation in one step. However it may be used to 475 inform inflate that a faster approach can be used for the single inflate() 476 call. Z_FINISH also informs inflate to not maintain a sliding window if the 477 stream completes, which reduces inflate's memory footprint. If the stream 478 does not complete, either because not all of the stream is provided or not 479 enough output space is provided, then a sliding window will be allocated and 480 inflate() can be called again to continue the operation as if Z_NO_FLUSH had 481 been used. 482 483 In this implementation, inflate() always flushes as much output as 484 possible to the output buffer, and always uses the faster approach on the 485 first call. So the effects of the flush parameter in this implementation are 486 on the return value of inflate() as noted below, when inflate() returns early 487 when Z_BLOCK or Z_TREES is used, and when inflate() avoids the allocation of 488 memory for a sliding window when Z_FINISH is used. 489 490 If a preset dictionary is needed after this call (see inflateSetDictionary 491 below), inflate sets strm->adler to the Adler-32 checksum of the dictionary 492 chosen by the compressor and returns Z_NEED_DICT; otherwise it sets 493 strm->adler to the Adler-32 checksum of all output produced so far (that is, 494 total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described 495 below. At the end of the stream, inflate() checks that its computed Adler-32 496 checksum is equal to that saved by the compressor and returns Z_STREAM_END 497 only if the checksum is correct. 498 499 inflate() can decompress and check either zlib-wrapped or gzip-wrapped 500 deflate data. The header type is detected automatically, if requested when 501 initializing with inflateInit2(). Any information contained in the gzip 502 header is not retained unless inflateGetHeader() is used. When processing 503 gzip-wrapped deflate data, strm->adler32 is set to the CRC-32 of the output 504 produced so far. The CRC-32 is checked against the gzip trailer, as is the 505 uncompressed length, modulo 2^32. 506 507 inflate() returns Z_OK if some progress has been made (more input processed 508 or more output produced), Z_STREAM_END if the end of the compressed data has 509 been reached and all uncompressed output has been produced, Z_NEED_DICT if a 510 preset dictionary is needed at this point, Z_DATA_ERROR if the input data was 511 corrupted (input stream not conforming to the zlib format or incorrect check 512 value, in which case strm->msg points to a string with a more specific 513 error), Z_STREAM_ERROR if the stream structure was inconsistent (for example 514 next_in or next_out was Z_NULL, or the state was inadvertently written over 515 by the application), Z_MEM_ERROR if there was not enough memory, Z_BUF_ERROR 516 if no progress was possible or if there was not enough room in the output 517 buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and 518 inflate() can be called again with more input and more output space to 519 continue decompressing. If Z_DATA_ERROR is returned, the application may 520 then call inflateSync() to look for a good compression block if a partial 521 recovery of the data is to be attempted. 522 */ 523 524 525 ZEXTERN int ZEXPORT inflateEnd(z_streamp strm); 526 /* 527 All dynamically allocated data structures for this stream are freed. 528 This function discards any unprocessed input and does not flush any pending 529 output. 530 531 inflateEnd returns Z_OK if success, or Z_STREAM_ERROR if the stream state 532 was inconsistent. 533 */ 534 535 536 /* Advanced functions */ 537 538 /* 539 The following functions are needed only in some special applications. 540 */ 541 542 /* 543 ZEXTERN int ZEXPORT deflateInit2(z_streamp strm, 544 int level, 545 int method, 546 int windowBits, 547 int memLevel, 548 int strategy); 549 550 This is another version of deflateInit with more compression options. The 551 fields zalloc, zfree and opaque must be initialized before by the caller. 552 553 The method parameter is the compression method. It must be Z_DEFLATED in 554 this version of the library. 555 556 The windowBits parameter is the base two logarithm of the window size 557 (the size of the history buffer). It should be in the range 8..15 for this 558 version of the library. Larger values of this parameter result in better 559 compression at the expense of memory usage. The default value is 15 if 560 deflateInit is used instead. 561 562 For the current implementation of deflate(), a windowBits value of 8 (a 563 window size of 256 bytes) is not supported. As a result, a request for 8 564 will result in 9 (a 512-byte window). In that case, providing 8 to 565 inflateInit2() will result in an error when the zlib header with 9 is 566 checked against the initialization of inflate(). The remedy is to not use 8 567 with deflateInit2() with this initialization, or at least in that case use 9 568 with inflateInit2(). 569 570 windowBits can also be -8..-15 for raw deflate. In this case, -windowBits 571 determines the window size. deflate() will then generate raw deflate data 572 with no zlib header or trailer, and will not compute a check value. 573 574 windowBits can also be greater than 15 for optional gzip encoding. Add 575 16 to windowBits to write a simple gzip header and trailer around the 576 compressed data instead of a zlib wrapper. The gzip header will have no 577 file name, no extra data, no comment, no modification time (set to zero), no 578 header crc, and the operating system will be set to the appropriate value, 579 if the operating system was determined at compile time. If a gzip stream is 580 being written, strm->adler is a CRC-32 instead of an Adler-32. 581 582 For raw deflate or gzip encoding, a request for a 256-byte window is 583 rejected as invalid, since only the zlib header provides a means of 584 transmitting the window size to the decompressor. 585 586 The memLevel parameter specifies how much memory should be allocated 587 for the internal compression state. memLevel=1 uses minimum memory but is 588 slow and reduces compression ratio; memLevel=9 uses maximum memory for 589 optimal speed. The default value is 8. See zconf.h for total memory usage 590 as a function of windowBits and memLevel. 591 592 The strategy parameter is used to tune the compression algorithm. Use the 593 value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a 594 filter (or predictor), Z_RLE to limit match distances to one (run-length 595 encoding), or Z_HUFFMAN_ONLY to force Huffman encoding only (no string 596 matching). Filtered data consists mostly of small values with a somewhat 597 random distribution, as produced by the PNG filters. In this case, the 598 compression algorithm is tuned to compress them better. The effect of 599 Z_FILTERED is to force more Huffman coding and less string matching than the 600 default; it is intermediate between Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY. 601 Z_RLE is almost as fast as Z_HUFFMAN_ONLY, but should give better 602 compression for PNG image data than Huffman only. The degree of string 603 matching from most to none is: Z_DEFAULT_STRATEGY, Z_FILTERED, Z_RLE, then 604 Z_HUFFMAN_ONLY. The strategy parameter affects the compression ratio but 605 never the correctness of the compressed output, even if it is not set 606 optimally for the given data. Z_FIXED uses the default string matching, but 607 prevents the use of dynamic Huffman codes, allowing for a simpler decoder 608 for special applications. 609 610 deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 611 memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid 612 method), or Z_VERSION_ERROR if the zlib library version (zlib_version) is 613 incompatible with the version assumed by the caller (ZLIB_VERSION). msg is 614 set to null if there is no error message. deflateInit2 does not perform any 615 compression: this will be done by deflate(). 616 */ 617 618 ZEXTERN int ZEXPORT deflateSetDictionary(z_streamp strm, 619 const Bytef *dictionary, 620 uInt dictLength); 621 /* 622 Initializes the compression dictionary from the given byte sequence 623 without producing any compressed output. When using the zlib format, this 624 function must be called immediately after deflateInit, deflateInit2 or 625 deflateReset, and before any call of deflate. When doing raw deflate, this 626 function must be called either before any call of deflate, or immediately 627 after the completion of a deflate block, i.e. after all input has been 628 consumed and all output has been delivered when using any of the flush 629 options Z_BLOCK, Z_PARTIAL_FLUSH, Z_SYNC_FLUSH, or Z_FULL_FLUSH. The 630 compressor and decompressor must use exactly the same dictionary (see 631 inflateSetDictionary). 632 633 The dictionary should consist of strings (byte sequences) that are likely 634 to be encountered later in the data to be compressed, with the most commonly 635 used strings preferably put towards the end of the dictionary. Using a 636 dictionary is most useful when the data to be compressed is short and can be 637 predicted with good accuracy; the data can then be compressed better than 638 with the default empty dictionary. 639 640 Depending on the size of the compression data structures selected by 641 deflateInit or deflateInit2, a part of the dictionary may in effect be 642 discarded, for example if the dictionary is larger than the window size 643 provided in deflateInit or deflateInit2. Thus the strings most likely to be 644 useful should be put at the end of the dictionary, not at the front. In 645 addition, the current implementation of deflate will use at most the window 646 size minus 262 bytes of the provided dictionary. 647 648 Upon return of this function, strm->adler is set to the Adler-32 value 649 of the dictionary; the decompressor may later use this value to determine 650 which dictionary has been used by the compressor. (The Adler-32 value 651 applies to the whole dictionary even if only a subset of the dictionary is 652 actually used by the compressor.) If a raw deflate was requested, then the 653 Adler-32 value is not computed and strm->adler is not set. 654 655 deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a 656 parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is 657 inconsistent (for example if deflate has already been called for this stream 658 or if not at a block boundary for raw deflate). deflateSetDictionary does 659 not perform any compression: this will be done by deflate(). 660 */ 661 662 ZEXTERN int ZEXPORT deflateGetDictionary(z_streamp strm, 663 Bytef *dictionary, 664 uInt *dictLength); 665 /* 666 Returns the sliding dictionary being maintained by deflate. dictLength is 667 set to the number of bytes in the dictionary, and that many bytes are copied 668 to dictionary. dictionary must have enough space, where 32768 bytes is 669 always enough. If deflateGetDictionary() is called with dictionary equal to 670 Z_NULL, then only the dictionary length is returned, and nothing is copied. 671 Similarly, if dictLength is Z_NULL, then it is not set. 672 673 deflateGetDictionary() may return a length less than the window size, even 674 when more than the window size in input has been provided. It may return up 675 to 258 bytes less in that case, due to how zlib's implementation of deflate 676 manages the sliding window and lookahead for matches, where matches can be 677 up to 258 bytes long. If the application needs the last window-size bytes of 678 input, then that would need to be saved by the application outside of zlib. 679 680 deflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the 681 stream state is inconsistent. 682 */ 683 684 ZEXTERN int ZEXPORT deflateCopy(z_streamp dest, 685 z_streamp source); 686 /* 687 Sets the destination stream as a complete copy of the source stream. 688 689 This function can be useful when several compression strategies will be 690 tried, for example when there are several ways of pre-processing the input 691 data with a filter. The streams that will be discarded should then be freed 692 by calling deflateEnd. Note that deflateCopy duplicates the internal 693 compression state which can be quite large, so this strategy is slow and can 694 consume lots of memory. 695 696 deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not 697 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent 698 (such as zalloc being Z_NULL). msg is left unchanged in both source and 699 destination. 700 */ 701 702 ZEXTERN int ZEXPORT deflateReset(z_streamp strm); 703 /* 704 This function is equivalent to deflateEnd followed by deflateInit, but 705 does not free and reallocate the internal compression state. The stream 706 will leave the compression level and any other attributes that may have been 707 set unchanged. total_in, total_out, adler, and msg are initialized. 708 709 deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source 710 stream state was inconsistent (such as zalloc or state being Z_NULL). 711 */ 712 713 ZEXTERN int ZEXPORT deflateParams(z_streamp strm, 714 int level, 715 int strategy); 716 /* 717 Dynamically update the compression level and compression strategy. The 718 interpretation of level and strategy is as in deflateInit2(). This can be 719 used to switch between compression and straight copy of the input data, or 720 to switch to a different kind of input data requiring a different strategy. 721 If the compression approach (which is a function of the level) or the 722 strategy is changed, and if there have been any deflate() calls since the 723 state was initialized or reset, then the input available so far is 724 compressed with the old level and strategy using deflate(strm, Z_BLOCK). 725 There are three approaches for the compression levels 0, 1..3, and 4..9 726 respectively. The new level and strategy will take effect at the next call 727 of deflate(). 728 729 If a deflate(strm, Z_BLOCK) is performed by deflateParams(), and it does 730 not have enough output space to complete, then the parameter change will not 731 take effect. In this case, deflateParams() can be called again with the 732 same parameters and more output space to try again. 733 734 In order to assure a change in the parameters on the first try, the 735 deflate stream should be flushed using deflate() with Z_BLOCK or other flush 736 request until strm.avail_out is not zero, before calling deflateParams(). 737 Then no more input data should be provided before the deflateParams() call. 738 If this is done, the old level and strategy will be applied to the data 739 compressed before deflateParams(), and the new level and strategy will be 740 applied to the data compressed after deflateParams(). 741 742 deflateParams returns Z_OK on success, Z_STREAM_ERROR if the source stream 743 state was inconsistent or if a parameter was invalid, or Z_BUF_ERROR if 744 there was not enough output space to complete the compression of the 745 available input data before a change in the strategy or approach. Note that 746 in the case of a Z_BUF_ERROR, the parameters are not changed. A return 747 value of Z_BUF_ERROR is not fatal, in which case deflateParams() can be 748 retried with more output space. 749 */ 750 751 ZEXTERN int ZEXPORT deflateTune(z_streamp strm, 752 int good_length, 753 int max_lazy, 754 int nice_length, 755 int max_chain); 756 /* 757 Fine tune deflate's internal compression parameters. This should only be 758 used by someone who understands the algorithm used by zlib's deflate for 759 searching for the best matching string, and even then only by the most 760 fanatic optimizer trying to squeeze out the last compressed bit for their 761 specific input data. Read the deflate.c source code for the meaning of the 762 max_lazy, good_length, nice_length, and max_chain parameters. 763 764 deflateTune() can be called after deflateInit() or deflateInit2(), and 765 returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream. 766 */ 767 768 ZEXTERN uLong ZEXPORT deflateBound(z_streamp strm, 769 uLong sourceLen); 770 /* 771 deflateBound() returns an upper bound on the compressed size after 772 deflation of sourceLen bytes. It must be called after deflateInit() or 773 deflateInit2(), and after deflateSetHeader(), if used. This would be used 774 to allocate an output buffer for deflation in a single pass, and so would be 775 called before deflate(). If that first deflate() call is provided the 776 sourceLen input bytes, an output buffer allocated to the size returned by 777 deflateBound(), and the flush value Z_FINISH, then deflate() is guaranteed 778 to return Z_STREAM_END. Note that it is possible for the compressed size to 779 be larger than the value returned by deflateBound() if flush options other 780 than Z_FINISH or Z_NO_FLUSH are used. 781 */ 782 783 ZEXTERN int ZEXPORT deflatePending(z_streamp strm, 784 unsigned *pending, 785 int *bits); 786 /* 787 deflatePending() returns the number of bytes and bits of output that have 788 been generated, but not yet provided in the available output. The bytes not 789 provided would be due to the available output space having being consumed. 790 The number of bits of output not provided are between 0 and 7, where they 791 await more bits to join them in order to fill out a full byte. If pending 792 or bits are Z_NULL, then those values are not set. 793 794 deflatePending returns Z_OK if success, or Z_STREAM_ERROR if the source 795 stream state was inconsistent. 796 */ 797 798 ZEXTERN int ZEXPORT deflateUsed(z_streamp strm, 799 int *bits); 800 /* 801 deflateUsed() returns in *bits the most recent number of deflate bits used 802 in the last byte when flushing to a byte boundary. The result is in 1..8, or 803 0 if there has not yet been a flush. This helps determine the location of 804 the last bit of a deflate stream. 805 806 deflateUsed returns Z_OK if success, or Z_STREAM_ERROR if the source 807 stream state was inconsistent. 808 */ 809 810 ZEXTERN int ZEXPORT deflatePrime(z_streamp strm, 811 int bits, 812 int value); 813 /* 814 deflatePrime() inserts bits in the deflate output stream. The intent 815 is that this function is used to start off the deflate output with the bits 816 leftover from a previous deflate stream when appending to it. As such, this 817 function can only be used for raw deflate, and must be used before the first 818 deflate() call after a deflateInit2() or deflateReset(). bits must be less 819 than or equal to 16, and that many of the least significant bits of value 820 will be inserted in the output. 821 822 deflatePrime returns Z_OK if success, Z_BUF_ERROR if there was not enough 823 room in the internal buffer to insert the bits, or Z_STREAM_ERROR if the 824 source stream state was inconsistent. 825 */ 826 827 ZEXTERN int ZEXPORT deflateSetHeader(z_streamp strm, 828 gz_headerp head); 829 /* 830 deflateSetHeader() provides gzip header information for when a gzip 831 stream is requested by deflateInit2(). deflateSetHeader() may be called 832 after deflateInit2() or deflateReset() and before the first call of 833 deflate(). The text, time, os, extra field, name, and comment information 834 in the provided gz_header structure are written to the gzip header (xflag is 835 ignored -- the extra flags are set according to the compression level). The 836 caller must assure that, if not Z_NULL, name and comment are terminated with 837 a zero byte, and that if extra is not Z_NULL, that extra_len bytes are 838 available there. If hcrc is true, a gzip header crc is included. Note that 839 the current versions of the command-line version of gzip (up through version 840 1.3.x) do not support header crc's, and will report that it is a "multi-part 841 gzip file" and give up. 842 843 If deflateSetHeader is not used, the default gzip header has text false, 844 the time set to zero, and os set to the current operating system, with no 845 extra, name, or comment fields. The gzip header is returned to the default 846 state by deflateReset(). 847 848 deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source 849 stream state was inconsistent. 850 */ 851 852 /* 853 ZEXTERN int ZEXPORT inflateInit2(z_streamp strm, 854 int windowBits); 855 856 This is another version of inflateInit with an extra parameter. The 857 fields next_in, avail_in, zalloc, zfree and opaque must be initialized 858 before by the caller. 859 860 The windowBits parameter is the base two logarithm of the maximum window 861 size (the size of the history buffer). It should be in the range 8..15 for 862 this version of the library. The default value is 15 if inflateInit is used 863 instead. windowBits must be greater than or equal to the windowBits value 864 provided to deflateInit2() while compressing, or it must be equal to 15 if 865 deflateInit2() was not used. If a compressed stream with a larger window 866 size is given as input, inflate() will return with the error code 867 Z_DATA_ERROR instead of trying to allocate a larger window. 868 869 windowBits can also be zero to request that inflate use the window size in 870 the zlib header of the compressed stream. 871 872 windowBits can also be -8..-15 for raw inflate. In this case, -windowBits 873 determines the window size. inflate() will then process raw deflate data, 874 not looking for a zlib or gzip header, not generating a check value, and not 875 looking for any check values for comparison at the end of the stream. This 876 is for use with other formats that use the deflate compressed data format 877 such as zip. Those formats provide their own check values. If a custom 878 format is developed using the raw deflate format for compressed data, it is 879 recommended that a check value such as an Adler-32 or a CRC-32 be applied to 880 the uncompressed data as is done in the zlib, gzip, and zip formats. For 881 most applications, the zlib format should be used as is. Note that comments 882 above on the use in deflateInit2() applies to the magnitude of windowBits. 883 884 windowBits can also be greater than 15 for optional gzip decoding. Add 885 32 to windowBits to enable zlib and gzip decoding with automatic header 886 detection, or add 16 to decode only the gzip format (the zlib format will 887 return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is a 888 CRC-32 instead of an Adler-32. Unlike the gunzip utility and gzread() (see 889 below), inflate() will *not* automatically decode concatenated gzip members. 890 inflate() will return Z_STREAM_END at the end of the gzip member. The state 891 would need to be reset to continue decoding a subsequent gzip member. This 892 *must* be done if there is more data after a gzip member, in order for the 893 decompression to be compliant with the gzip standard (RFC 1952). 894 895 inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 896 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the 897 version assumed by the caller, or Z_STREAM_ERROR if the parameters are 898 invalid, such as a null pointer to the structure. msg is set to null if 899 there is no error message. inflateInit2 does not perform any decompression 900 apart from possibly reading the zlib header if present: actual decompression 901 will be done by inflate(). (So next_in and avail_in may be modified, but 902 next_out and avail_out are unused and unchanged.) The current implementation 903 of inflateInit2() does not process any header information -- that is 904 deferred until inflate() is called. 905 */ 906 907 ZEXTERN int ZEXPORT inflateSetDictionary(z_streamp strm, 908 const Bytef *dictionary, 909 uInt dictLength); 910 /* 911 Initializes the decompression dictionary from the given uncompressed byte 912 sequence. This function must be called immediately after a call of inflate, 913 if that call returned Z_NEED_DICT. The dictionary chosen by the compressor 914 can be determined from the Adler-32 value returned by that call of inflate. 915 The compressor and decompressor must use exactly the same dictionary (see 916 deflateSetDictionary). For raw inflate, this function can be called at any 917 time to set the dictionary. If the provided dictionary is smaller than the 918 window and there is already data in the window, then the provided dictionary 919 will amend what's there. The application must insure that the dictionary 920 that was used for compression is provided. 921 922 inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a 923 parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is 924 inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the 925 expected one (incorrect Adler-32 value). inflateSetDictionary does not 926 perform any decompression: this will be done by subsequent calls of 927 inflate(). 928 */ 929 930 ZEXTERN int ZEXPORT inflateGetDictionary(z_streamp strm, 931 Bytef *dictionary, 932 uInt *dictLength); 933 /* 934 Returns the sliding dictionary being maintained by inflate. dictLength is 935 set to the number of bytes in the dictionary, and that many bytes are copied 936 to dictionary. dictionary must have enough space, where 32768 bytes is 937 always enough. If inflateGetDictionary() is called with dictionary equal to 938 Z_NULL, then only the dictionary length is returned, and nothing is copied. 939 Similarly, if dictLength is Z_NULL, then it is not set. 940 941 inflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the 942 stream state is inconsistent. 943 */ 944 945 ZEXTERN int ZEXPORT inflateSync(z_streamp strm); 946 /* 947 Skips invalid compressed data until a possible full flush point (see above 948 for the description of deflate with Z_FULL_FLUSH) can be found, or until all 949 available input is skipped. No output is provided. 950 951 inflateSync searches for a 00 00 FF FF pattern in the compressed data. 952 All full flush points have this pattern, but not all occurrences of this 953 pattern are full flush points. 954 955 inflateSync returns Z_OK if a possible full flush point has been found, 956 Z_BUF_ERROR if no more input was provided, Z_DATA_ERROR if no flush point 957 has been found, or Z_STREAM_ERROR if the stream structure was inconsistent. 958 In the success case, the application may save the current value of total_in 959 which indicates where valid compressed data was found. In the error case, 960 the application may repeatedly call inflateSync, providing more input each 961 time, until success or end of the input data. 962 */ 963 964 ZEXTERN int ZEXPORT inflateCopy(z_streamp dest, 965 z_streamp source); 966 /* 967 Sets the destination stream as a complete copy of the source stream. 968 969 This function can be useful when randomly accessing a large stream. The 970 first pass through the stream can periodically record the inflate state, 971 allowing restarting inflate at those points when randomly accessing the 972 stream. 973 974 inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not 975 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent 976 (such as zalloc being Z_NULL). msg is left unchanged in both source and 977 destination. 978 */ 979 980 ZEXTERN int ZEXPORT inflateReset(z_streamp strm); 981 /* 982 This function is equivalent to inflateEnd followed by inflateInit, 983 but does not free and reallocate the internal decompression state. The 984 stream will keep attributes that may have been set by inflateInit2. 985 total_in, total_out, adler, and msg are initialized. 986 987 inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source 988 stream state was inconsistent (such as zalloc or state being Z_NULL). 989 */ 990 991 ZEXTERN int ZEXPORT inflateReset2(z_streamp strm, 992 int windowBits); 993 /* 994 This function is the same as inflateReset, but it also permits changing 995 the wrap and window size requests. The windowBits parameter is interpreted 996 the same as it is for inflateInit2. If the window size is changed, then the 997 memory allocated for the window is freed, and the window will be reallocated 998 by inflate() if needed. 999 1000 inflateReset2 returns Z_OK if success, or Z_STREAM_ERROR if the source 1001 stream state was inconsistent (such as zalloc or state being Z_NULL), or if 1002 the windowBits parameter is invalid. 1003 */ 1004 1005 ZEXTERN int ZEXPORT inflatePrime(z_streamp strm, 1006 int bits, 1007 int value); 1008 /* 1009 This function inserts bits in the inflate input stream. The intent is 1010 that this function is used to start inflating at a bit position in the 1011 middle of a byte. The provided bits will be used before any bytes are used 1012 from next_in. This function should only be used with raw inflate, and 1013 should be used before the first inflate() call after inflateInit2() or 1014 inflateReset(). bits must be less than or equal to 16, and that many of the 1015 least significant bits of value will be inserted in the input. 1016 1017 If bits is negative, then the input stream bit buffer is emptied. Then 1018 inflatePrime() can be called again to put bits in the buffer. This is used 1019 to clear out bits leftover after feeding inflate a block description prior 1020 to feeding inflate codes. 1021 1022 inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source 1023 stream state was inconsistent. 1024 */ 1025 1026 ZEXTERN long ZEXPORT inflateMark(z_streamp strm); 1027 /* 1028 This function returns two values, one in the lower 16 bits of the return 1029 value, and the other in the remaining upper bits, obtained by shifting the 1030 return value down 16 bits. If the upper value is -1 and the lower value is 1031 zero, then inflate() is currently decoding information outside of a block. 1032 If the upper value is -1 and the lower value is non-zero, then inflate is in 1033 the middle of a stored block, with the lower value equaling the number of 1034 bytes from the input remaining to copy. If the upper value is not -1, then 1035 it is the number of bits back from the current bit position in the input of 1036 the code (literal or length/distance pair) currently being processed. In 1037 that case the lower value is the number of bytes already emitted for that 1038 code. 1039 1040 A code is being processed if inflate is waiting for more input to complete 1041 decoding of the code, or if it has completed decoding but is waiting for 1042 more output space to write the literal or match data. 1043 1044 inflateMark() is used to mark locations in the input data for random 1045 access, which may be at bit positions, and to note those cases where the 1046 output of a code may span boundaries of random access blocks. The current 1047 location in the input stream can be determined from avail_in and data_type 1048 as noted in the description for the Z_BLOCK flush parameter for inflate. 1049 1050 inflateMark returns the value noted above, or -65536 if the provided 1051 source stream state was inconsistent. 1052 */ 1053 1054 ZEXTERN int ZEXPORT inflateGetHeader(z_streamp strm, 1055 gz_headerp head); 1056 /* 1057 inflateGetHeader() requests that gzip header information be stored in the 1058 provided gz_header structure. inflateGetHeader() may be called after 1059 inflateInit2() or inflateReset(), and before the first call of inflate(). 1060 As inflate() processes the gzip stream, head->done is zero until the header 1061 is completed, at which time head->done is set to one. If a zlib stream is 1062 being decoded, then head->done is set to -1 to indicate that there will be 1063 no gzip header information forthcoming. Note that Z_BLOCK or Z_TREES can be 1064 used to force inflate() to return immediately after header processing is 1065 complete and before any actual data is decompressed. 1066 1067 The text, time, xflags, and os fields are filled in with the gzip header 1068 contents. hcrc is set to true if there is a header CRC. (The header CRC 1069 was valid if done is set to one.) If extra is not Z_NULL, then extra_max 1070 contains the maximum number of bytes to write to extra. Once done is true, 1071 extra_len contains the actual extra field length, and extra contains the 1072 extra field, or that field truncated if extra_max is less than extra_len. 1073 If name is not Z_NULL, then up to name_max characters are written there, 1074 terminated with a zero unless the length is greater than name_max. If 1075 comment is not Z_NULL, then up to comm_max characters are written there, 1076 terminated with a zero unless the length is greater than comm_max. When any 1077 of extra, name, or comment are not Z_NULL and the respective field is not 1078 present in the header, then that field is set to Z_NULL to signal its 1079 absence. This allows the use of deflateSetHeader() with the returned 1080 structure to duplicate the header. However if those fields are set to 1081 allocated memory, then the application will need to save those pointers 1082 elsewhere so that they can be eventually freed. 1083 1084 If inflateGetHeader is not used, then the header information is simply 1085 discarded. The header is always checked for validity, including the header 1086 CRC if present. inflateReset() will reset the process to discard the header 1087 information. The application would need to call inflateGetHeader() again to 1088 retrieve the header from the next gzip stream. 1089 1090 inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source 1091 stream state was inconsistent. 1092 */ 1093 1094 /* 1095 ZEXTERN int ZEXPORT inflateBackInit(z_streamp strm, int windowBits, 1096 unsigned char FAR *window); 1097 1098 Initialize the internal stream state for decompression using inflateBack() 1099 calls. The fields zalloc, zfree and opaque in strm must be initialized 1100 before the call. If zalloc and zfree are Z_NULL, then the default library- 1101 derived memory allocation routines are used. windowBits is the base two 1102 logarithm of the window size, in the range 8..15. window is a caller 1103 supplied buffer of that size. Except for special applications where it is 1104 assured that deflate was used with small window sizes, windowBits must be 15 1105 and a 32K byte window must be supplied to be able to decompress general 1106 deflate streams. 1107 1108 See inflateBack() for the usage of these routines. 1109 1110 inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of 1111 the parameters are invalid, Z_MEM_ERROR if the internal state could not be 1112 allocated, or Z_VERSION_ERROR if the version of the library does not match 1113 the version of the header file. 1114 */ 1115 1116 typedef unsigned (*in_func)(void FAR *, 1117 z_const unsigned char FAR * FAR *); 1118 typedef int (*out_func)(void FAR *, unsigned char FAR *, unsigned); 1119 1120 ZEXTERN int ZEXPORT inflateBack(z_streamp strm, 1121 in_func in, void FAR *in_desc, 1122 out_func out, void FAR *out_desc); 1123 /* 1124 inflateBack() does a raw inflate with a single call using a call-back 1125 interface for input and output. This is potentially more efficient than 1126 inflate() for file i/o applications, in that it avoids copying between the 1127 output and the sliding window by simply making the window itself the output 1128 buffer. inflate() can be faster on modern CPUs when used with large 1129 buffers. inflateBack() trusts the application to not change the output 1130 buffer passed by the output function, at least until inflateBack() returns. 1131 1132 inflateBackInit() must be called first to allocate the internal state 1133 and to initialize the state with the user-provided window buffer. 1134 inflateBack() may then be used multiple times to inflate a complete, raw 1135 deflate stream with each call. inflateBackEnd() is then called to free the 1136 allocated state. 1137 1138 A raw deflate stream is one with no zlib or gzip header or trailer. 1139 This routine would normally be used in a utility that reads zip or gzip 1140 files and writes out uncompressed files. The utility would decode the 1141 header and process the trailer on its own, hence this routine expects only 1142 the raw deflate stream to decompress. This is different from the default 1143 behavior of inflate(), which expects a zlib header and trailer around the 1144 deflate stream. 1145 1146 inflateBack() uses two subroutines supplied by the caller that are then 1147 called by inflateBack() for input and output. inflateBack() calls those 1148 routines until it reads a complete deflate stream and writes out all of the 1149 uncompressed data, or until it encounters an error. The function's 1150 parameters and return types are defined above in the in_func and out_func 1151 typedefs. inflateBack() will call in(in_desc, &buf) which should return the 1152 number of bytes of provided input, and a pointer to that input in buf. If 1153 there is no input available, in() must return zero -- buf is ignored in that 1154 case -- and inflateBack() will return a buffer error. inflateBack() will 1155 call out(out_desc, buf, len) to write the uncompressed data buf[0..len-1]. 1156 out() should return zero on success, or non-zero on failure. If out() 1157 returns non-zero, inflateBack() will return with an error. Neither in() nor 1158 out() are permitted to change the contents of the window provided to 1159 inflateBackInit(), which is also the buffer that out() uses to write from. 1160 The length written by out() will be at most the window size. Any non-zero 1161 amount of input may be provided by in(). 1162 1163 For convenience, inflateBack() can be provided input on the first call by 1164 setting strm->next_in and strm->avail_in. If that input is exhausted, then 1165 in() will be called. Therefore strm->next_in must be initialized before 1166 calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called 1167 immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in 1168 must also be initialized, and then if strm->avail_in is not zero, input will 1169 initially be taken from strm->next_in[0 .. strm->avail_in - 1]. 1170 1171 The in_desc and out_desc parameters of inflateBack() is passed as the 1172 first parameter of in() and out() respectively when they are called. These 1173 descriptors can be optionally used to pass any information that the caller- 1174 supplied in() and out() functions need to do their job. 1175 1176 On return, inflateBack() will set strm->next_in and strm->avail_in to 1177 pass back any unused input that was provided by the last in() call. The 1178 return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR 1179 if in() or out() returned an error, Z_DATA_ERROR if there was a format error 1180 in the deflate stream (in which case strm->msg is set to indicate the nature 1181 of the error), or Z_STREAM_ERROR if the stream was not properly initialized. 1182 In the case of Z_BUF_ERROR, an input or output error can be distinguished 1183 using strm->next_in which will be Z_NULL only if in() returned an error. If 1184 strm->next_in is not Z_NULL, then the Z_BUF_ERROR was due to out() returning 1185 non-zero. (in() will always be called before out(), so strm->next_in is 1186 assured to be defined if out() returns non-zero.) Note that inflateBack() 1187 cannot return Z_OK. 1188 */ 1189 1190 ZEXTERN int ZEXPORT inflateBackEnd(z_streamp strm); 1191 /* 1192 All memory allocated by inflateBackInit() is freed. 1193 1194 inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream 1195 state was inconsistent. 1196 */ 1197 1198 ZEXTERN uLong ZEXPORT zlibCompileFlags(void); 1199 /* Return flags indicating compile-time options. 1200 1201 Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other: 1202 1.0: size of uInt 1203 3.2: size of uLong 1204 5.4: size of voidpf (pointer) 1205 7.6: size of z_off_t 1206 1207 Compiler, assembler, and debug options: 1208 8: ZLIB_DEBUG 1209 9: ASMV or ASMINF -- use ASM code 1210 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention 1211 11: 0 (reserved) 1212 1213 One-time table building (smaller code, but not thread-safe if true): 1214 12: BUILDFIXED -- build static block decoding tables when needed 1215 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed 1216 14,15: 0 (reserved) 1217 1218 Library content (indicates missing functionality): 1219 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking 1220 deflate code when not needed) 1221 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect 1222 and decode gzip streams (to avoid linking crc code) 1223 18-19: 0 (reserved) 1224 1225 Operation variations (changes in library functionality): 1226 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate 1227 21: FASTEST -- deflate algorithm with only one, lowest compression level 1228 22,23: 0 (reserved) 1229 1230 The sprintf variant used by gzprintf (zero is best): 1231 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format 1232 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure! 1233 26: 0 = returns value, 1 = void -- 1 means inferred string length returned 1234 1235 Remainder: 1236 27-31: 0 (reserved) 1237 */ 1238 1239 #ifndef Z_SOLO 1240 1241 /* utility functions */ 1242 1243 /* 1244 The following utility functions are implemented on top of the basic 1245 stream-oriented functions. To simplify the interface, some default options 1246 are assumed (compression level and memory usage, standard memory allocation 1247 functions). The source code of these utility functions can be modified if 1248 you need special options. 1249 */ 1250 1251 ZEXTERN int ZEXPORT compress(Bytef *dest, uLongf *destLen, 1252 const Bytef *source, uLong sourceLen); 1253 /* 1254 Compresses the source buffer into the destination buffer. sourceLen is 1255 the byte length of the source buffer. Upon entry, destLen is the total size 1256 of the 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. compress() is equivalent to compress2() with a level 1259 parameter of Z_DEFAULT_COMPRESSION. 1260 1261 compress returns Z_OK if success, Z_MEM_ERROR if there was not 1262 enough memory, Z_BUF_ERROR if there was not enough room in the output 1263 buffer. 1264 */ 1265 1266 ZEXTERN int ZEXPORT compress2(Bytef *dest, uLongf *destLen, 1267 const Bytef *source, uLong sourceLen, 1268 int level); 1269 /* 1270 Compresses the source buffer into the destination buffer. The level 1271 parameter has the same meaning as in deflateInit. sourceLen is the byte 1272 length of the source buffer. Upon entry, destLen is the total size of the 1273 destination buffer, which must be at least the value returned by 1274 compressBound(sourceLen). Upon exit, destLen is the actual size of the 1275 compressed data. 1276 1277 compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 1278 memory, Z_BUF_ERROR if there was not enough room in the output buffer, 1279 Z_STREAM_ERROR if the level parameter is invalid. 1280 */ 1281 1282 ZEXTERN uLong ZEXPORT compressBound(uLong sourceLen); 1283 /* 1284 compressBound() returns an upper bound on the compressed size after 1285 compress() or compress2() on sourceLen bytes. It would be used before a 1286 compress() or compress2() call to allocate the destination buffer. 1287 */ 1288 1289 ZEXTERN int ZEXPORT uncompress(Bytef *dest, uLongf *destLen, 1290 const Bytef *source, uLong sourceLen); 1291 /* 1292 Decompresses the source buffer into the destination buffer. sourceLen is 1293 the byte length of the source buffer. Upon entry, destLen is the total size 1294 of the destination buffer, which must be large enough to hold the entire 1295 uncompressed data. (The size of the uncompressed data must have been saved 1296 previously by the compressor and transmitted to the decompressor by some 1297 mechanism outside the scope of this compression library.) Upon exit, destLen 1298 is the actual size of the uncompressed data. 1299 1300 uncompress returns Z_OK if success, Z_MEM_ERROR if there was not 1301 enough memory, Z_BUF_ERROR if there was not enough room in the output 1302 buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete. In 1303 the case where there is not enough room, uncompress() will fill the output 1304 buffer with the uncompressed data up to that point. 1305 */ 1306 1307 ZEXTERN int ZEXPORT uncompress2(Bytef *dest, uLongf *destLen, 1308 const Bytef *source, uLong *sourceLen); 1309 /* 1310 Same as uncompress, except that sourceLen is a pointer, where the 1311 length of the source is *sourceLen. On return, *sourceLen is the number of 1312 source bytes consumed. 1313 */ 1314 1315 /* gzip file access functions */ 1316 1317 /* 1318 This library supports reading and writing files in gzip (.gz) format with 1319 an interface similar to that of stdio, using the functions that start with 1320 "gz". The gzip format is different from the zlib format. gzip is a gzip 1321 wrapper, documented in RFC 1952, wrapped around a deflate stream. 1322 */ 1323 1324 typedef struct gzFile_s *gzFile; /* semi-opaque gzip file descriptor */ 1325 1326 /* 1327 ZEXTERN gzFile ZEXPORT gzopen(const char *path, const char *mode); 1328 1329 Open the gzip (.gz) file at path for reading and decompressing, or 1330 compressing and writing. The mode parameter is as in fopen ("rb" or "wb") 1331 but can also include a compression level ("wb9") or a strategy: 'f' for 1332 filtered data as in "wb6f", 'h' for Huffman-only compression as in "wb1h", 1333 'R' for run-length encoding as in "wb1R", or 'F' for fixed code compression 1334 as in "wb9F". (See the description of deflateInit2 for more information 1335 about the strategy parameter.) 'T' will request transparent writing or 1336 appending with no compression and not using the gzip format. 1337 1338 "a" can be used instead of "w" to request that the gzip stream that will 1339 be written be appended to the file. "+" will result in an error, since 1340 reading and writing to the same gzip file is not supported. The addition of 1341 "x" when writing will create the file exclusively, which fails if the file 1342 already exists. On systems that support it, the addition of "e" when 1343 reading or writing will set the flag to close the file on an execve() call. 1344 1345 These functions, as well as gzip, will read and decode a sequence of gzip 1346 streams in a file. The append function of gzopen() can be used to create 1347 such a file. (Also see gzflush() for another way to do this.) When 1348 appending, gzopen does not test whether the file begins with a gzip stream, 1349 nor does it look for the end of the gzip streams to begin appending. gzopen 1350 will simply append a gzip stream to the existing file. 1351 1352 gzopen can be used to read a file which is not in gzip format; in this 1353 case gzread will directly read from the file without decompression. When 1354 reading, this will be detected automatically by looking for the magic two- 1355 byte gzip header. 1356 1357 gzopen returns NULL if the file could not be opened, if there was 1358 insufficient memory to allocate the gzFile state, or if an invalid mode was 1359 specified (an 'r', 'w', or 'a' was not provided, or '+' was provided). 1360 errno can be checked to determine if the reason gzopen failed was that the 1361 file could not be opened. 1362 */ 1363 1364 ZEXTERN gzFile ZEXPORT gzdopen(int fd, const char *mode); 1365 /* 1366 Associate a gzFile with the file descriptor fd. File descriptors are 1367 obtained from calls like open, dup, creat, pipe or fileno (if the file has 1368 been previously opened with fopen). The mode parameter is as in gzopen. 1369 1370 The next call of gzclose on the returned gzFile will also close the file 1371 descriptor fd, just like fclose(fdopen(fd, mode)) closes the file descriptor 1372 fd. If you want to keep fd open, use fd = dup(fd_keep); gz = gzdopen(fd, 1373 mode);. The duplicated descriptor should be saved to avoid a leak, since 1374 gzdopen does not close fd if it fails. If you are using fileno() to get the 1375 file descriptor from a FILE *, then you will have to use dup() to avoid 1376 double-close()ing the file descriptor. Both gzclose() and fclose() will 1377 close the associated file descriptor, so they need to have different file 1378 descriptors. 1379 1380 gzdopen returns NULL if there was insufficient memory to allocate the 1381 gzFile state, if an invalid mode was specified (an 'r', 'w', or 'a' was not 1382 provided, or '+' was provided), or if fd is -1. The file descriptor is not 1383 used until the next gz* read, write, seek, or close operation, so gzdopen 1384 will not detect if fd is invalid (unless fd is -1). 1385 */ 1386 1387 ZEXTERN int ZEXPORT gzbuffer(gzFile file, unsigned size); 1388 /* 1389 Set the internal buffer size used by this library's functions for file to 1390 size. The default buffer size is 8192 bytes. This function must be called 1391 after gzopen() or gzdopen(), and before any other calls that read or write 1392 the file. The buffer memory allocation is always deferred to the first read 1393 or write. Three times that size in buffer space is allocated. A larger 1394 buffer size of, for example, 64K or 128K bytes will noticeably increase the 1395 speed of decompression (reading). 1396 1397 The new buffer size also affects the maximum length for gzprintf(). 1398 1399 gzbuffer() returns 0 on success, or -1 on failure, such as being called 1400 too late. 1401 */ 1402 1403 ZEXTERN int ZEXPORT gzsetparams(gzFile file, int level, int strategy); 1404 /* 1405 Dynamically update the compression level and strategy for file. See the 1406 description of deflateInit2 for the meaning of these parameters. Previously 1407 provided data is flushed before applying the parameter changes. 1408 1409 gzsetparams returns Z_OK if success, Z_STREAM_ERROR if the file was not 1410 opened for writing, Z_ERRNO if there is an error writing the flushed data, 1411 or Z_MEM_ERROR if there is a memory allocation error. 1412 */ 1413 1414 ZEXTERN int ZEXPORT gzread(gzFile file, voidp buf, unsigned len); 1415 /* 1416 Read and decompress up to len uncompressed bytes from file into buf. If 1417 the input file is not in gzip format, gzread copies the given number of 1418 bytes into the buffer directly from the file. 1419 1420 After reaching the end of a gzip stream in the input, gzread will continue 1421 to read, looking for another gzip stream. Any number of gzip streams may be 1422 concatenated in the input file, and will all be decompressed by gzread(). 1423 If something other than a gzip stream is encountered after a gzip stream, 1424 that remaining trailing garbage is ignored (and no error is returned). 1425 1426 gzread can be used to read a gzip file that is being concurrently written. 1427 Upon reaching the end of the input, gzread will return with the available 1428 data. If the error code returned by gzerror is Z_OK or Z_BUF_ERROR, then 1429 gzclearerr can be used to clear the end of file indicator in order to permit 1430 gzread to be tried again. Z_OK indicates that a gzip stream was completed 1431 on the last gzread. Z_BUF_ERROR indicates that the input file ended in the 1432 middle of a gzip stream. Note that gzread does not return -1 in the event 1433 of an incomplete gzip stream. This error is deferred until gzclose(), which 1434 will return Z_BUF_ERROR if the last gzread ended in the middle of a gzip 1435 stream. Alternatively, gzerror can be used before gzclose to detect this 1436 case. 1437 1438 gzread returns the number of uncompressed bytes actually read, less than 1439 len for end of file, or -1 for error. If len is too large to fit in an int, 1440 then nothing is read, -1 is returned, and the error state is set to 1441 Z_STREAM_ERROR. 1442 */ 1443 1444 ZEXTERN z_size_t ZEXPORT gzfread(voidp buf, z_size_t size, z_size_t nitems, 1445 gzFile file); 1446 /* 1447 Read and decompress up to nitems items of size size from file into buf, 1448 otherwise operating as gzread() does. This duplicates the interface of 1449 stdio's fread(), with size_t request and return types. If the library 1450 defines size_t, then z_size_t is identical to size_t. If not, then z_size_t 1451 is an unsigned integer type that can contain a pointer. 1452 1453 gzfread() returns the number of full items read of size size, or zero if 1454 the end of the file was reached and a full item could not be read, or if 1455 there was an error. gzerror() must be consulted if zero is returned in 1456 order to determine if there was an error. If the multiplication of size and 1457 nitems overflows, i.e. the product does not fit in a z_size_t, then nothing 1458 is read, zero is returned, and the error state is set to Z_STREAM_ERROR. 1459 1460 In the event that the end of file is reached and only a partial item is 1461 available at the end, i.e. the remaining uncompressed data length is not a 1462 multiple of size, then the final partial item is nevertheless read into buf 1463 and the end-of-file flag is set. The length of the partial item read is not 1464 provided, but could be inferred from the result of gztell(). This behavior 1465 is the same as the behavior of fread() implementations in common libraries, 1466 but it prevents the direct use of gzfread() to read a concurrently written 1467 file, resetting and retrying on end-of-file, when size is not 1. 1468 */ 1469 1470 ZEXTERN int ZEXPORT gzwrite(gzFile file, voidpc buf, unsigned len); 1471 /* 1472 Compress and write the len uncompressed bytes at buf to file. gzwrite 1473 returns the number of uncompressed bytes written or 0 in case of error. 1474 */ 1475 1476 ZEXTERN z_size_t ZEXPORT gzfwrite(voidpc buf, z_size_t size, 1477 z_size_t nitems, gzFile file); 1478 /* 1479 Compress and write nitems items of size size from buf to file, duplicating 1480 the interface of stdio's fwrite(), with size_t request and return types. If 1481 the library defines size_t, then z_size_t is identical to size_t. If not, 1482 then z_size_t is an unsigned integer type that can contain a pointer. 1483 1484 gzfwrite() returns the number of full items written of size size, or zero 1485 if there was an error. If the multiplication of size and nitems overflows, 1486 i.e. the product does not fit in a z_size_t, then nothing is written, zero 1487 is returned, and the error state is set to Z_STREAM_ERROR. 1488 */ 1489 1490 ZEXTERN int ZEXPORTVA gzprintf(gzFile file, const char *format, ...); 1491 /* 1492 Convert, format, compress, and write the arguments (...) to file under 1493 control of the string format, as in fprintf. gzprintf returns the number of 1494 uncompressed bytes actually written, or a negative zlib error code in case 1495 of error. The number of uncompressed bytes written is limited to 8191, or 1496 one less than the buffer size given to gzbuffer(). The caller should assure 1497 that this limit is not exceeded. If it is exceeded, then gzprintf() will 1498 return an error (0) with nothing written. In this case, there may also be a 1499 buffer overflow with unpredictable consequences, which is possible only if 1500 zlib was compiled with the insecure functions sprintf() or vsprintf(), 1501 because the secure snprintf() or vsnprintf() functions were not available. 1502 This can be determined using zlibCompileFlags(). 1503 */ 1504 1505 ZEXTERN int ZEXPORT gzputs(gzFile file, const char *s); 1506 /* 1507 Compress and write the given null-terminated string s to file, excluding 1508 the terminating null character. 1509 1510 gzputs returns the number of characters written, or -1 in case of error. 1511 */ 1512 1513 ZEXTERN char * ZEXPORT gzgets(gzFile file, char *buf, int len); 1514 /* 1515 Read and decompress bytes from file into buf, until len-1 characters are 1516 read, or until a newline character is read and transferred to buf, or an 1517 end-of-file condition is encountered. If any characters are read or if len 1518 is one, the string is terminated with a null character. If no characters 1519 are read due to an end-of-file or len is less than one, then the buffer is 1520 left untouched. 1521 1522 gzgets returns buf which is a null-terminated string, or it returns NULL 1523 for end-of-file or in case of error. If there was an error, the contents at 1524 buf are indeterminate. 1525 */ 1526 1527 ZEXTERN int ZEXPORT gzputc(gzFile file, int c); 1528 /* 1529 Compress and write c, converted to an unsigned char, into file. gzputc 1530 returns the value that was written, or -1 in case of error. 1531 */ 1532 1533 ZEXTERN int ZEXPORT gzgetc(gzFile file); 1534 /* 1535 Read and decompress one byte from file. gzgetc returns this byte or -1 1536 in case of end of file or error. This is implemented as a macro for speed. 1537 As such, it does not do all of the checking the other functions do. I.e. 1538 it does not check to see if file is NULL, nor whether the structure file 1539 points to has been clobbered or not. 1540 */ 1541 1542 ZEXTERN int ZEXPORT gzungetc(int c, gzFile file); 1543 /* 1544 Push c back onto the stream for file to be read as the first character on 1545 the next read. At least one character of push-back is always allowed. 1546 gzungetc() returns the character pushed, or -1 on failure. gzungetc() will 1547 fail if c is -1, and may fail if a character has been pushed but not read 1548 yet. If gzungetc is used immediately after gzopen or gzdopen, at least the 1549 output buffer size of pushed characters is allowed. (See gzbuffer above.) 1550 The pushed character will be discarded if the stream is repositioned with 1551 gzseek() or gzrewind(). 1552 */ 1553 1554 ZEXTERN int ZEXPORT gzflush(gzFile file, int flush); 1555 /* 1556 Flush all pending output to file. The parameter flush is as in the 1557 deflate() function. The return value is the zlib error number (see function 1558 gzerror below). gzflush is only permitted when writing. 1559 1560 If the flush parameter is Z_FINISH, the remaining data is written and the 1561 gzip stream is completed in the output. If gzwrite() is called again, a new 1562 gzip stream will be started in the output. gzread() is able to read such 1563 concatenated gzip streams. 1564 1565 gzflush should be called only when strictly necessary because it will 1566 degrade compression if called too often. 1567 */ 1568 1569 /* 1570 ZEXTERN z_off_t ZEXPORT gzseek(gzFile file, 1571 z_off_t offset, int whence); 1572 1573 Set the starting position to offset relative to whence for the next gzread 1574 or gzwrite on file. The offset represents a number of bytes in the 1575 uncompressed data stream. The whence parameter is defined as in lseek(2); 1576 the value SEEK_END is not supported. 1577 1578 If the file is opened for reading, this function is emulated but can be 1579 extremely slow. If the file is opened for writing, only forward seeks are 1580 supported; gzseek then compresses a sequence of zeroes up to the new 1581 starting position. 1582 1583 gzseek returns the resulting offset location as measured in bytes from 1584 the beginning of the uncompressed stream, or -1 in case of error, in 1585 particular if the file is opened for writing and the new starting position 1586 would be before the current position. 1587 */ 1588 1589 ZEXTERN int ZEXPORT gzrewind(gzFile file); 1590 /* 1591 Rewind file. This function is supported only for reading. 1592 1593 gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET). 1594 */ 1595 1596 /* 1597 ZEXTERN z_off_t ZEXPORT gztell(gzFile file); 1598 1599 Return the starting position for the next gzread or gzwrite on file. 1600 This position represents a number of bytes in the uncompressed data stream, 1601 and is zero when starting, even if appending or reading a gzip stream from 1602 the middle of a file using gzdopen(). 1603 1604 gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR) 1605 */ 1606 1607 /* 1608 ZEXTERN z_off_t ZEXPORT gzoffset(gzFile file); 1609 1610 Return the current compressed (actual) read or write offset of file. This 1611 offset includes the count of bytes that precede the gzip stream, for example 1612 when appending or when using gzdopen() for reading. When reading, the 1613 offset does not include as yet unused buffered input. This information can 1614 be used for a progress indicator. On error, gzoffset() returns -1. 1615 */ 1616 1617 ZEXTERN int ZEXPORT gzeof(gzFile file); 1618 /* 1619 Return true (1) if the end-of-file indicator for file has been set while 1620 reading, false (0) otherwise. Note that the end-of-file indicator is set 1621 only if the read tried to go past the end of the input, but came up short. 1622 Therefore, just like feof(), gzeof() may return false even if there is no 1623 more data to read, in the event that the last read request was for the exact 1624 number of bytes remaining in the input file. This will happen if the input 1625 file size is an exact multiple of the buffer size. 1626 1627 If gzeof() returns true, then the read functions will return no more data, 1628 unless the end-of-file indicator is reset by gzclearerr() and the input file 1629 has grown since the previous end of file was detected. 1630 */ 1631 1632 ZEXTERN int ZEXPORT gzdirect(gzFile file); 1633 /* 1634 Return true (1) if file is being copied directly while reading, or false 1635 (0) if file is a gzip stream being decompressed. 1636 1637 If the input file is empty, gzdirect() will return true, since the input 1638 does not contain a gzip stream. 1639 1640 If gzdirect() is used immediately after gzopen() or gzdopen() it will 1641 cause buffers to be allocated to allow reading the file to determine if it 1642 is a gzip file. Therefore if gzbuffer() is used, it should be called before 1643 gzdirect(). 1644 1645 When writing, gzdirect() returns true (1) if transparent writing was 1646 requested ("wT" for the gzopen() mode), or false (0) otherwise. (Note: 1647 gzdirect() is not needed when writing. Transparent writing must be 1648 explicitly requested, so the application already knows the answer. When 1649 linking statically, using gzdirect() will include all of the zlib code for 1650 gzip file reading and decompression, which may not be desired.) 1651 */ 1652 1653 ZEXTERN int ZEXPORT gzclose(gzFile file); 1654 /* 1655 Flush all pending output for file, if necessary, close file and 1656 deallocate the (de)compression state. Note that once file is closed, you 1657 cannot call gzerror with file, since its structures have been deallocated. 1658 gzclose must not be called more than once on the same file, just as free 1659 must not be called more than once on the same allocation. 1660 1661 gzclose will return Z_STREAM_ERROR if file is not valid, Z_ERRNO on a 1662 file operation error, Z_MEM_ERROR if out of memory, Z_BUF_ERROR if the 1663 last read ended in the middle of a gzip stream, or Z_OK on success. 1664 */ 1665 1666 ZEXTERN int ZEXPORT gzclose_r(gzFile file); 1667 ZEXTERN int ZEXPORT gzclose_w(gzFile file); 1668 /* 1669 Same as gzclose(), but gzclose_r() is only for use when reading, and 1670 gzclose_w() is only for use when writing or appending. The advantage to 1671 using these instead of gzclose() is that they avoid linking in zlib 1672 compression or decompression code that is not used when only reading or only 1673 writing respectively. If gzclose() is used, then both compression and 1674 decompression code will be included the application when linking to a static 1675 zlib library. 1676 */ 1677 1678 ZEXTERN const char * ZEXPORT gzerror(gzFile file, int *errnum); 1679 /* 1680 Return the error message for the last error which occurred on file. 1681 errnum is set to zlib error number. If an error occurred in the file system 1682 and not in the compression library, errnum is set to Z_ERRNO and the 1683 application may consult errno to get the exact error code. 1684 1685 The application must not modify the returned string. Future calls to 1686 this function may invalidate the previously returned string. If file is 1687 closed, then the string previously returned by gzerror will no longer be 1688 available. 1689 1690 gzerror() should be used to distinguish errors from end-of-file for those 1691 functions above that do not distinguish those cases in their return values. 1692 */ 1693 1694 ZEXTERN void ZEXPORT gzclearerr(gzFile file); 1695 /* 1696 Clear the error and end-of-file flags for file. This is analogous to the 1697 clearerr() function in stdio. This is useful for continuing to read a gzip 1698 file that is being written concurrently. 1699 */ 1700 1701 #endif /* !Z_SOLO */ 1702 1703 /* checksum functions */ 1704 1705 /* 1706 These functions are not related to compression but are exported 1707 anyway because they might be useful in applications using the compression 1708 library. 1709 */ 1710 1711 ZEXTERN uLong ZEXPORT adler32(uLong adler, const Bytef *buf, uInt len); 1712 /* 1713 Update a running Adler-32 checksum with the bytes buf[0..len-1] and 1714 return the updated checksum. An Adler-32 value is in the range of a 32-bit 1715 unsigned integer. If buf is Z_NULL, this function returns the required 1716 initial value for the checksum. 1717 1718 An Adler-32 checksum is almost as reliable as a CRC-32 but can be computed 1719 much faster. 1720 1721 Usage example: 1722 1723 uLong adler = adler32(0L, Z_NULL, 0); 1724 1725 while (read_buffer(buffer, length) != EOF) { 1726 adler = adler32(adler, buffer, length); 1727 } 1728 if (adler != original_adler) error(); 1729 */ 1730 1731 ZEXTERN uLong ZEXPORT adler32_z(uLong adler, const Bytef *buf, 1732 z_size_t len); 1733 /* 1734 Same as adler32(), but with a size_t length. 1735 */ 1736 1737 /* 1738 ZEXTERN uLong ZEXPORT adler32_combine(uLong adler1, uLong adler2, 1739 z_off_t len2); 1740 1741 Combine two Adler-32 checksums into one. For two sequences of bytes, seq1 1742 and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for 1743 each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of 1744 seq1 and seq2 concatenated, requiring only adler1, adler2, and len2. Note 1745 that the z_off_t type (like off_t) is a signed integer. If len2 is 1746 negative, the result has no meaning or utility. 1747 */ 1748 1749 ZEXTERN uLong ZEXPORT crc32(uLong crc, const Bytef *buf, uInt len); 1750 /* 1751 Update a running CRC-32 with the bytes buf[0..len-1] and return the 1752 updated CRC-32. A CRC-32 value is in the range of a 32-bit unsigned integer. 1753 If buf is Z_NULL, this function returns the required initial value for the 1754 crc. Pre- and post-conditioning (one's complement) is performed within this 1755 function so it shouldn't be done by the application. 1756 1757 Usage example: 1758 1759 uLong crc = crc32(0L, Z_NULL, 0); 1760 1761 while (read_buffer(buffer, length) != EOF) { 1762 crc = crc32(crc, buffer, length); 1763 } 1764 if (crc != original_crc) error(); 1765 */ 1766 1767 ZEXTERN uLong ZEXPORT crc32_z(uLong crc, const Bytef *buf, 1768 z_size_t len); 1769 /* 1770 Same as crc32(), but with a size_t length. 1771 */ 1772 1773 /* 1774 ZEXTERN uLong ZEXPORT crc32_combine(uLong crc1, uLong crc2, z_off_t len2); 1775 1776 Combine two CRC-32 check values into one. For two sequences of bytes, 1777 seq1 and seq2 with lengths len1 and len2, CRC-32 check values were 1778 calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32 1779 check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and 1780 len2. len2 must be non-negative. 1781 */ 1782 1783 /* 1784 ZEXTERN uLong ZEXPORT crc32_combine_gen(z_off_t len2); 1785 1786 Return the operator corresponding to length len2, to be used with 1787 crc32_combine_op(). len2 must be non-negative. 1788 */ 1789 1790 ZEXTERN uLong ZEXPORT crc32_combine_op(uLong crc1, uLong crc2, uLong op); 1791 /* 1792 Give the same result as crc32_combine(), using op in place of len2. op is 1793 is generated from len2 by crc32_combine_gen(). This will be faster than 1794 crc32_combine() if the generated op is used more than once. 1795 */ 1796 1797 1798 /* various hacks, don't look :) */ 1799 1800 /* deflateInit and inflateInit are macros to allow checking the zlib version 1801 * and the compiler's view of z_stream: 1802 */ 1803 ZEXTERN int ZEXPORT deflateInit_(z_streamp strm, int level, 1804 const char *version, int stream_size); 1805 ZEXTERN int ZEXPORT inflateInit_(z_streamp strm, 1806 const char *version, int stream_size); 1807 ZEXTERN int ZEXPORT deflateInit2_(z_streamp strm, int level, int method, 1808 int windowBits, int memLevel, 1809 int strategy, const char *version, 1810 int stream_size); 1811 ZEXTERN int ZEXPORT inflateInit2_(z_streamp strm, int windowBits, 1812 const char *version, int stream_size); 1813 ZEXTERN int ZEXPORT inflateBackInit_(z_streamp strm, int windowBits, 1814 unsigned char FAR *window, 1815 const char *version, 1816 int stream_size); 1817 #ifdef Z_PREFIX_SET 1818 # define z_deflateInit(strm, level) \ 1819 deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream)) 1820 # define z_inflateInit(strm) \ 1821 inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream)) 1822 # define z_deflateInit2(strm, level, method, windowBits, memLevel, strategy) \ 1823 deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\ 1824 (strategy), ZLIB_VERSION, (int)sizeof(z_stream)) 1825 # define z_inflateInit2(strm, windowBits) \ 1826 inflateInit2_((strm), (windowBits), ZLIB_VERSION, \ 1827 (int)sizeof(z_stream)) 1828 # define z_inflateBackInit(strm, windowBits, window) \ 1829 inflateBackInit_((strm), (windowBits), (window), \ 1830 ZLIB_VERSION, (int)sizeof(z_stream)) 1831 #else 1832 # define deflateInit(strm, level) \ 1833 deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream)) 1834 # define inflateInit(strm) \ 1835 inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream)) 1836 # define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \ 1837 deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\ 1838 (strategy), ZLIB_VERSION, (int)sizeof(z_stream)) 1839 # define inflateInit2(strm, windowBits) \ 1840 inflateInit2_((strm), (windowBits), ZLIB_VERSION, \ 1841 (int)sizeof(z_stream)) 1842 # define inflateBackInit(strm, windowBits, window) \ 1843 inflateBackInit_((strm), (windowBits), (window), \ 1844 ZLIB_VERSION, (int)sizeof(z_stream)) 1845 #endif 1846 1847 #ifndef Z_SOLO 1848 1849 /* gzgetc() macro and its supporting function and exposed data structure. Note 1850 * that the real internal state is much larger than the exposed structure. 1851 * This abbreviated structure exposes just enough for the gzgetc() macro. The 1852 * user should not mess with these exposed elements, since their names or 1853 * behavior could change in the future, perhaps even capriciously. They can 1854 * only be used by the gzgetc() macro. You have been warned. 1855 */ 1856 struct gzFile_s { 1857 unsigned have; 1858 unsigned char *next; 1859 z_off64_t pos; 1860 }; 1861 ZEXTERN int ZEXPORT gzgetc_(gzFile file); /* backward compatibility */ 1862 #ifdef Z_PREFIX_SET 1863 # undef z_gzgetc 1864 # define z_gzgetc(g) \ 1865 ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : (gzgetc)(g)) 1866 #else 1867 # define gzgetc(g) \ 1868 ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : (gzgetc)(g)) 1869 #endif 1870 1871 /* provide 64-bit offset functions if _LARGEFILE64_SOURCE defined, and/or 1872 * change the regular functions to 64 bits if _FILE_OFFSET_BITS is 64 (if 1873 * both are true, the application gets the *64 functions, and the regular 1874 * functions are changed to 64 bits) -- in case these are set on systems 1875 * without large file support, _LFS64_LARGEFILE must also be true 1876 */ 1877 #ifdef Z_LARGE64 1878 ZEXTERN gzFile ZEXPORT gzopen64(const char *, const char *); 1879 ZEXTERN z_off64_t ZEXPORT gzseek64(gzFile, z_off64_t, int); 1880 ZEXTERN z_off64_t ZEXPORT gztell64(gzFile); 1881 ZEXTERN z_off64_t ZEXPORT gzoffset64(gzFile); 1882 ZEXTERN uLong ZEXPORT adler32_combine64(uLong, uLong, z_off64_t); 1883 ZEXTERN uLong ZEXPORT crc32_combine64(uLong, uLong, z_off64_t); 1884 ZEXTERN uLong ZEXPORT crc32_combine_gen64(z_off64_t); 1885 #endif 1886 1887 #if !defined(ZLIB_INTERNAL) && defined(Z_WANT64) 1888 # ifdef Z_PREFIX_SET 1889 # define z_gzopen z_gzopen64 1890 # define z_gzseek z_gzseek64 1891 # define z_gztell z_gztell64 1892 # define z_gzoffset z_gzoffset64 1893 # define z_adler32_combine z_adler32_combine64 1894 # define z_crc32_combine z_crc32_combine64 1895 # define z_crc32_combine_gen z_crc32_combine_gen64 1896 # else 1897 # define gzopen gzopen64 1898 # define gzseek gzseek64 1899 # define gztell gztell64 1900 # define gzoffset gzoffset64 1901 # define adler32_combine adler32_combine64 1902 # define crc32_combine crc32_combine64 1903 # define crc32_combine_gen crc32_combine_gen64 1904 # endif 1905 # ifndef Z_LARGE64 1906 ZEXTERN gzFile ZEXPORT gzopen64(const char *, const char *); 1907 ZEXTERN z_off_t ZEXPORT gzseek64(gzFile, z_off_t, int); 1908 ZEXTERN z_off_t ZEXPORT gztell64(gzFile); 1909 ZEXTERN z_off_t ZEXPORT gzoffset64(gzFile); 1910 ZEXTERN uLong ZEXPORT adler32_combine64(uLong, uLong, z_off64_t); 1911 ZEXTERN uLong ZEXPORT crc32_combine64(uLong, uLong, z_off64_t); 1912 ZEXTERN uLong ZEXPORT crc32_combine_gen64(z_off64_t); 1913 # endif 1914 #else 1915 ZEXTERN gzFile ZEXPORT gzopen(const char *, const char *); 1916 ZEXTERN z_off_t ZEXPORT gzseek(gzFile, z_off_t, int); 1917 ZEXTERN z_off_t ZEXPORT gztell(gzFile); 1918 ZEXTERN z_off_t ZEXPORT gzoffset(gzFile); 1919 ZEXTERN uLong ZEXPORT adler32_combine(uLong, uLong, z_off_t); 1920 ZEXTERN uLong ZEXPORT crc32_combine(uLong, uLong, z_off_t); 1921 ZEXTERN uLong ZEXPORT crc32_combine_gen(z_off_t); 1922 #endif 1923 1924 #else /* Z_SOLO */ 1925 1926 ZEXTERN uLong ZEXPORT adler32_combine(uLong, uLong, z_off_t); 1927 ZEXTERN uLong ZEXPORT crc32_combine(uLong, uLong, z_off_t); 1928 ZEXTERN uLong ZEXPORT crc32_combine_gen(z_off_t); 1929 1930 #endif /* !Z_SOLO */ 1931 1932 /* undocumented functions */ 1933 ZEXTERN const char * ZEXPORT zError(int); 1934 ZEXTERN int ZEXPORT inflateSyncPoint(z_streamp); 1935 ZEXTERN const z_crc_t FAR * ZEXPORT get_crc_table(void); 1936 ZEXTERN int ZEXPORT inflateUndermine(z_streamp, int); 1937 ZEXTERN int ZEXPORT inflateValidate(z_streamp, int); 1938 ZEXTERN unsigned long ZEXPORT inflateCodesUsed(z_streamp); 1939 ZEXTERN int ZEXPORT inflateResetKeep(z_streamp); 1940 ZEXTERN int ZEXPORT deflateResetKeep(z_streamp); 1941 #if defined(_WIN32) && !defined(Z_SOLO) 1942 ZEXTERN gzFile ZEXPORT gzopen_w(const wchar_t *path, 1943 const char *mode); 1944 #endif 1945 #if defined(STDC) || defined(Z_HAVE_STDARG_H) 1946 # ifndef Z_SOLO 1947 ZEXTERN int ZEXPORTVA gzvprintf(gzFile file, 1948 const char *format, 1949 va_list va); 1950 # endif 1951 #endif 1952 1953 #ifdef __cplusplus 1954 } 1955 #endif 1956 1957 #endif /* ZLIB_H */ 1958