1 /* zlib.h -- interface of the 'zlib' general purpose compression library 2 version 1.2.11, January 15th, 2017 3 4 Copyright (C) 1995-2017 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 #include "zconf.h" 35 36 #ifdef __cplusplus 37 extern "C" { 38 #endif 39 40 #define ZLIB_VERSION "1.2.11" 41 #define ZLIB_VERNUM 0x12b0 42 #define ZLIB_VER_MAJOR 1 43 #define ZLIB_VER_MINOR 2 44 #define ZLIB_VER_REVISION 11 45 #define ZLIB_VER_SUBREVISION 0 46 47 /* 48 The 'zlib' compression library provides in-memory compression and 49 decompression functions, including integrity checks of the uncompressed data. 50 This version of the library supports only one compression method (deflation) 51 but other algorithms will be added later and will have the same stream 52 interface. 53 54 Compression can be done in a single step if the buffers are large enough, 55 or can be done by repeated calls of the compression function. In the latter 56 case, the application must provide more input and/or consume the output 57 (providing more output space) before each call. 58 59 The compressed data format used by default by the in-memory functions is 60 the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped 61 around a deflate stream, which is itself documented in RFC 1951. 62 63 The library also supports reading and writing files in gzip (.gz) format 64 with an interface similar to that of stdio using the functions that start 65 with "gz". The gzip format is different from the zlib format. gzip is a 66 gzip wrapper, documented in RFC 1952, wrapped around a deflate stream. 67 68 This library can optionally read and write gzip and raw deflate streams in 69 memory as well. 70 71 The zlib format was designed to be compact and fast for use in memory 72 and on communications channels. The gzip format was designed for single- 73 file compression on file systems, has a larger header than zlib to maintain 74 directory information, and uses a different, slower check method than zlib. 75 76 The library does not install any signal handler. The decoder checks 77 the consistency of the compressed data, so the library should never crash 78 even in the case of corrupted input. 79 */ 80 81 typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size)); 82 typedef void (*free_func) OF((voidpf opaque, voidpf address)); 83 84 struct internal_state; 85 86 typedef struct z_stream_s { 87 z_const Bytef *next_in; /* next input byte */ 88 uInt avail_in; /* number of bytes available at next_in */ 89 uLong total_in; /* total number of input bytes read so far */ 90 91 Bytef *next_out; /* next output byte will go here */ 92 uInt avail_out; /* remaining free space at next_out */ 93 uLong total_out; /* total number of bytes output so far */ 94 95 z_const char *msg; /* last error message, NULL if no error */ 96 struct internal_state FAR *state; /* not visible by applications */ 97 98 alloc_func zalloc; /* used to allocate the internal state */ 99 free_func zfree; /* used to free the internal state */ 100 voidpf opaque; /* private data object passed to zalloc and zfree */ 101 102 int data_type; /* best guess about the data type: binary or text 103 for deflate, or the decoding state for inflate */ 104 uLong adler; /* Adler-32 or CRC-32 value of the uncompressed data */ 105 uLong reserved; /* reserved for future use */ 106 107 #define VGZ_EXTENSIONS 1 108 uLong start_bit; /* Bit pos of first deflate block */ 109 uLong stop_bit; /* Bit pos after last deflate block */ 110 uLong last_bit; /* Bit pos of 'last' bit */ 111 } z_stream; 112 113 typedef z_stream FAR *z_streamp; 114 115 /* 116 gzip header information passed to and from zlib routines. See RFC 1952 117 for more details on the meanings of these fields. 118 */ 119 typedef struct gz_header_s { 120 int text; /* true if compressed data believed to be text */ 121 uLong time; /* modification time */ 122 int xflags; /* extra flags (not used when writing a gzip file) */ 123 int os; /* operating system */ 124 Bytef *extra; /* pointer to extra field or Z_NULL if none */ 125 uInt extra_len; /* extra field length (valid if extra != Z_NULL) */ 126 uInt extra_max; /* space at extra (only when reading header) */ 127 Bytef *name; /* pointer to zero-terminated file name or Z_NULL */ 128 uInt name_max; /* space at name (only when reading header) */ 129 Bytef *comment; /* pointer to zero-terminated comment or Z_NULL */ 130 uInt comm_max; /* space at comment (only when reading header) */ 131 int hcrc; /* true if there was or will be a header crc */ 132 int done; /* true when done reading gzip header (not used 133 when writing a gzip file) */ 134 } gz_header; 135 136 typedef gz_header FAR *gz_headerp; 137 138 /* 139 The application must update next_in and avail_in when avail_in has dropped 140 to zero. It must update next_out and avail_out when avail_out has dropped 141 to zero. The application must initialize zalloc, zfree and opaque before 142 calling the init function. All other fields are set by the compression 143 library and must not be updated by the application. 144 145 The opaque value provided by the application will be passed as the first 146 parameter for calls of zalloc and zfree. This can be useful for custom 147 memory management. The compression library attaches no meaning to the 148 opaque value. 149 150 zalloc must return Z_NULL if there is not enough memory for the object. 151 If zlib is used in a multi-threaded application, zalloc and zfree must be 152 thread safe. In that case, zlib is thread-safe. When zalloc and zfree are 153 Z_NULL on entry to the initialization function, they are set to internal 154 routines that use the standard library functions malloc() and free(). 155 156 On 16-bit systems, the functions zalloc and zfree must be able to allocate 157 exactly 65536 bytes, but will not be required to allocate more than this if 158 the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, pointers 159 returned by zalloc for objects of exactly 65536 bytes *must* have their 160 offset normalized to zero. The default allocation function provided by this 161 library ensures this (see zutil.c). To reduce memory requirements and avoid 162 any allocation of 64K objects, at the expense of compression ratio, compile 163 the library with -DMAX_WBITS=14 (see zconf.h). 164 165 The fields total_in and total_out can be used for statistics or progress 166 reports. After compression, total_in holds the total size of the 167 uncompressed data and may be saved for use by the decompressor (particularly 168 if the decompressor wants to decompress everything in a single step). 169 */ 170 171 /* constants */ 172 173 #define Z_NO_FLUSH 0 174 #define Z_PARTIAL_FLUSH 1 175 #define Z_SYNC_FLUSH 2 176 #define Z_FULL_FLUSH 3 177 #define Z_FINISH 4 178 #define Z_BLOCK 5 179 #define Z_TREES 6 180 /* Allowed flush values; see deflate() and inflate() below for details */ 181 182 #define Z_OK 0 183 #define Z_STREAM_END 1 184 #define Z_NEED_DICT 2 185 #define Z_ERRNO (-1) 186 #define Z_STREAM_ERROR (-2) 187 #define Z_DATA_ERROR (-3) 188 #define Z_MEM_ERROR (-4) 189 #define Z_BUF_ERROR (-5) 190 #define Z_VERSION_ERROR (-6) 191 /* Return codes for the compression/decompression functions. Negative values 192 * are errors, positive values are used for special but normal events. 193 */ 194 195 #define Z_NO_COMPRESSION 0 196 #define Z_BEST_SPEED 1 197 #define Z_BEST_COMPRESSION 9 198 #define Z_DEFAULT_COMPRESSION (-1) 199 /* compression levels */ 200 201 #define Z_FILTERED 1 202 #define Z_HUFFMAN_ONLY 2 203 #define Z_RLE 3 204 #define Z_FIXED 4 205 #define Z_DEFAULT_STRATEGY 0 206 /* compression strategy; see deflateInit2() below for details */ 207 208 #define Z_BINARY 0 209 #define Z_TEXT 1 210 #define Z_ASCII Z_TEXT /* for compatibility with 1.2.2 and earlier */ 211 #define Z_UNKNOWN 2 212 /* Possible values of the data_type field for deflate() */ 213 214 #define Z_DEFLATED 8 215 /* The deflate compression method (the only one supported in this version) */ 216 217 #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */ 218 219 #define zlib_version zlibVersion() 220 /* for compatibility with versions < 1.0.2 */ 221 222 223 /* basic functions */ 224 225 ZEXTERN const char * ZEXPORT zlibVersion OF((void)); 226 /* The application can compare zlibVersion and ZLIB_VERSION for consistency. 227 If the first character differs, the library code actually used is not 228 compatible with the zlib.h header file used by the application. This check 229 is automatically made by deflateInit and inflateInit. 230 */ 231 232 /* 233 ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level)); 234 235 Initializes the internal stream state for compression. The fields 236 zalloc, zfree and opaque must be initialized before by the caller. If 237 zalloc and zfree are set to Z_NULL, deflateInit updates them to use default 238 allocation functions. 239 240 The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9: 241 1 gives best speed, 9 gives best compression, 0 gives no compression at all 242 (the input data is simply copied a block at a time). Z_DEFAULT_COMPRESSION 243 requests a default compromise between speed and compression (currently 244 equivalent to level 6). 245 246 deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough 247 memory, Z_STREAM_ERROR if level is not a valid compression level, or 248 Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible 249 with the version assumed by the caller (ZLIB_VERSION). msg is set to null 250 if there is no error message. deflateInit does not perform any compression: 251 this will be done by deflate(). 252 */ 253 254 255 ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush)); 256 /* 257 deflate compresses as much data as possible, and stops when the input 258 buffer becomes empty or the output buffer becomes full. It may introduce 259 some output latency (reading input without producing any output) except when 260 forced to flush. 261 262 The detailed semantics are as follows. deflate performs one or both of the 263 following actions: 264 265 - Compress more input starting at next_in and update next_in and avail_in 266 accordingly. If not all input can be processed (because there is not 267 enough room in the output buffer), next_in and avail_in are updated and 268 processing will resume at this point for the next call of deflate(). 269 270 - Generate more output starting at next_out and update next_out and avail_out 271 accordingly. This action is forced if the parameter flush is non zero. 272 Forcing flush frequently degrades the compression ratio, so this parameter 273 should be set only when necessary. Some output may be provided even if 274 flush is zero. 275 276 Before the call of deflate(), the application should ensure that at least 277 one of the actions is possible, by providing more input and/or consuming more 278 output, and updating avail_in or avail_out accordingly; avail_out should 279 never be zero before the call. The application can consume the compressed 280 output when it wants, for example when the output buffer is full (avail_out 281 == 0), or after each call of deflate(). If deflate returns Z_OK and with 282 zero avail_out, it must be called again after making room in the output 283 buffer because there might be more output pending. See deflatePending(), 284 which can be used if desired to determine whether or not there is more ouput 285 in that case. 286 287 Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to 288 decide how much data to accumulate before producing output, in order to 289 maximize compression. 290 291 If the parameter flush is set to Z_SYNC_FLUSH, all pending output is 292 flushed to the output buffer and the output is aligned on a byte boundary, so 293 that the decompressor can get all input data available so far. (In 294 particular avail_in is zero after the call if enough output space has been 295 provided before the call.) Flushing may degrade compression for some 296 compression algorithms and so it should be used only when necessary. This 297 completes the current deflate block and follows it with an empty stored block 298 that is three bits plus filler bits to the next byte, followed by four bytes 299 (00 00 ff ff). 300 301 If flush is set to Z_PARTIAL_FLUSH, all pending output is flushed to the 302 output buffer, but the output is not aligned to a byte boundary. All of the 303 input data so far will be available to the decompressor, as for Z_SYNC_FLUSH. 304 This completes the current deflate block and follows it with an empty fixed 305 codes block that is 10 bits long. This assures that enough bytes are output 306 in order for the decompressor to finish the block before the empty fixed 307 codes block. 308 309 If flush is set to Z_BLOCK, a deflate block is completed and emitted, as 310 for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to 311 seven bits of the current block are held to be written as the next byte after 312 the next deflate block is completed. In this case, the decompressor may not 313 be provided enough bits at this point in order to complete decompression of 314 the data provided so far to the compressor. It may need to wait for the next 315 block to be emitted. This is for advanced applications that need to control 316 the emission of deflate blocks. 317 318 If flush is set to Z_FULL_FLUSH, all output is flushed as with 319 Z_SYNC_FLUSH, and the compression state is reset so that decompression can 320 restart from this point if previous compressed data has been damaged or if 321 random access is desired. Using Z_FULL_FLUSH too often can seriously degrade 322 compression. 323 324 If deflate returns with avail_out == 0, this function must be called again 325 with the same value of the flush parameter and more output space (updated 326 avail_out), until the flush is complete (deflate returns with non-zero 327 avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that 328 avail_out is greater than six to avoid repeated flush markers due to 329 avail_out == 0 on return. 330 331 If the parameter flush is set to Z_FINISH, pending input is processed, 332 pending output is flushed and deflate returns with Z_STREAM_END if there was 333 enough output space. If deflate returns with Z_OK or Z_BUF_ERROR, this 334 function must be called again with Z_FINISH and more output space (updated 335 avail_out) but no more input data, until it returns with Z_STREAM_END or an 336 error. After deflate has returned Z_STREAM_END, the only possible operations 337 on the stream are deflateReset or deflateEnd. 338 339 Z_FINISH can be used in the first deflate call after deflateInit if all the 340 compression is to be done in a single step. In order to complete in one 341 call, avail_out must be at least the value returned by deflateBound (see 342 below). Then deflate is guaranteed to return Z_STREAM_END. If not enough 343 output space is provided, deflate will not return Z_STREAM_END, and it must 344 be called again as described above. 345 346 deflate() sets strm->adler to the Adler-32 checksum of all input read 347 so far (that is, total_in bytes). If a gzip stream is being generated, then 348 strm->adler will be the CRC-32 checksum of the input read so far. (See 349 deflateInit2 below.) 350 351 deflate() may update strm->data_type if it can make a good guess about 352 the input data type (Z_BINARY or Z_TEXT). If in doubt, the data is 353 considered binary. This field is only for information purposes and does not 354 affect the compression algorithm in any manner. 355 356 deflate() returns Z_OK if some progress has been made (more input 357 processed or more output produced), Z_STREAM_END if all input has been 358 consumed and all output has been produced (only when flush is set to 359 Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example 360 if next_in or next_out was Z_NULL or the state was inadvertently written over 361 by the application), or Z_BUF_ERROR if no progress is possible (for example 362 avail_in or avail_out was zero). Note that Z_BUF_ERROR is not fatal, and 363 deflate() can be called again with more input and more output space to 364 continue compressing. 365 */ 366 367 368 ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm)); 369 /* 370 All dynamically allocated data structures for this stream are freed. 371 This function discards any unprocessed input and does not flush any pending 372 output. 373 374 deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the 375 stream state was inconsistent, Z_DATA_ERROR if the stream was freed 376 prematurely (some input or output was discarded). In the error case, msg 377 may be set but then points to a static string (which must not be 378 deallocated). 379 */ 380 381 382 /* 383 ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm)); 384 385 Initializes the internal stream state for decompression. The fields 386 next_in, avail_in, zalloc, zfree and opaque must be initialized before by 387 the caller. In the current version of inflate, the provided input is not 388 read or consumed. The allocation of a sliding window will be deferred to 389 the first call of inflate (if the decompression does not complete on the 390 first call). If zalloc and zfree are set to Z_NULL, inflateInit updates 391 them to use default allocation functions. 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 OF((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 OF((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 OF((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 next_in, zalloc, zfree and opaque must be initialized before by the 552 caller. 553 554 The method parameter is the compression method. It must be Z_DEFLATED in 555 this version of the library. 556 557 The windowBits parameter is the base two logarithm of the window size 558 (the size of the history buffer). It should be in the range 8..15 for this 559 version of the library. Larger values of this parameter result in better 560 compression at the expense of memory usage. The default value is 15 if 561 deflateInit is used instead. 562 563 For the current implementation of deflate(), a windowBits value of 8 (a 564 window size of 256 bytes) is not supported. As a result, a request for 8 565 will result in 9 (a 512-byte window). In that case, providing 8 to 566 inflateInit2() will result in an error when the zlib header with 9 is 567 checked against the initialization of inflate(). The remedy is to not use 8 568 with deflateInit2() with this initialization, or at least in that case use 9 569 with inflateInit2(). 570 571 windowBits can also be -8..-15 for raw deflate. In this case, -windowBits 572 determines the window size. deflate() will then generate raw deflate data 573 with no zlib header or trailer, and will not compute a check value. 574 575 windowBits can also be greater than 15 for optional gzip encoding. Add 576 16 to windowBits to write a simple gzip header and trailer around the 577 compressed data instead of a zlib wrapper. The gzip header will have no 578 file name, no extra data, no comment, no modification time (set to zero), no 579 header crc, and the operating system will be set to the appropriate value, 580 if the operating system was determined at compile time. If a gzip stream is 581 being written, strm->adler is a CRC-32 instead of an Adler-32. 582 583 For raw deflate or gzip encoding, a request for a 256-byte window is 584 rejected as invalid, since only the zlib header provides a means of 585 transmitting the window size to the decompressor. 586 587 The memLevel parameter specifies how much memory should be allocated 588 for the internal compression state. memLevel=1 uses minimum memory but is 589 slow and reduces compression ratio; memLevel=9 uses maximum memory for 590 optimal speed. The default value is 8. See zconf.h for total memory usage 591 as a function of windowBits and memLevel. 592 593 The strategy parameter is used to tune the compression algorithm. Use the 594 value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a 595 filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no 596 string match), or Z_RLE to limit match distances to one (run-length 597 encoding). Filtered data consists mostly of small values with a somewhat 598 random distribution. In this case, the compression algorithm is tuned to 599 compress them better. The effect of Z_FILTERED is to force more Huffman 600 coding and less string matching; it is somewhat intermediate between 601 Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as 602 fast as Z_HUFFMAN_ONLY, but give better compression for PNG image data. The 603 strategy parameter only affects the compression ratio but not the 604 correctness of the compressed output even if it is not set appropriately. 605 Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler 606 decoder for special applications. 607 608 deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 609 memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid 610 method), or Z_VERSION_ERROR if the zlib library version (zlib_version) is 611 incompatible with the version assumed by the caller (ZLIB_VERSION). msg is 612 set to null if there is no error message. deflateInit2 does not perform any 613 compression: this will be done by deflate(). 614 */ 615 616 ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm, 617 const Bytef *dictionary, 618 uInt dictLength)); 619 /* 620 Initializes the compression dictionary from the given byte sequence 621 without producing any compressed output. When using the zlib format, this 622 function must be called immediately after deflateInit, deflateInit2 or 623 deflateReset, and before any call of deflate. When doing raw deflate, this 624 function must be called either before any call of deflate, or immediately 625 after the completion of a deflate block, i.e. after all input has been 626 consumed and all output has been delivered when using any of the flush 627 options Z_BLOCK, Z_PARTIAL_FLUSH, Z_SYNC_FLUSH, or Z_FULL_FLUSH. The 628 compressor and decompressor must use exactly the same dictionary (see 629 inflateSetDictionary). 630 631 The dictionary should consist of strings (byte sequences) that are likely 632 to be encountered later in the data to be compressed, with the most commonly 633 used strings preferably put towards the end of the dictionary. Using a 634 dictionary is most useful when the data to be compressed is short and can be 635 predicted with good accuracy; the data can then be compressed better than 636 with the default empty dictionary. 637 638 Depending on the size of the compression data structures selected by 639 deflateInit or deflateInit2, a part of the dictionary may in effect be 640 discarded, for example if the dictionary is larger than the window size 641 provided in deflateInit or deflateInit2. Thus the strings most likely to be 642 useful should be put at the end of the dictionary, not at the front. In 643 addition, the current implementation of deflate will use at most the window 644 size minus 262 bytes of the provided dictionary. 645 646 Upon return of this function, strm->adler is set to the Adler-32 value 647 of the dictionary; the decompressor may later use this value to determine 648 which dictionary has been used by the compressor. (The Adler-32 value 649 applies to the whole dictionary even if only a subset of the dictionary is 650 actually used by the compressor.) If a raw deflate was requested, then the 651 Adler-32 value is not computed and strm->adler is not set. 652 653 deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a 654 parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is 655 inconsistent (for example if deflate has already been called for this stream 656 or if not at a block boundary for raw deflate). deflateSetDictionary does 657 not perform any compression: this will be done by deflate(). 658 */ 659 660 ZEXTERN int ZEXPORT deflateGetDictionary OF((z_streamp strm, 661 Bytef *dictionary, 662 uInt *dictLength)); 663 /* 664 Returns the sliding dictionary being maintained by deflate. dictLength is 665 set to the number of bytes in the dictionary, and that many bytes are copied 666 to dictionary. dictionary must have enough space, where 32768 bytes is 667 always enough. If deflateGetDictionary() is called with dictionary equal to 668 Z_NULL, then only the dictionary length is returned, and nothing is copied. 669 Similary, if dictLength is Z_NULL, then it is not set. 670 671 deflateGetDictionary() may return a length less than the window size, even 672 when more than the window size in input has been provided. It may return up 673 to 258 bytes less in that case, due to how zlib's implementation of deflate 674 manages the sliding window and lookahead for matches, where matches can be 675 up to 258 bytes long. If the application needs the last window-size bytes of 676 input, then that would need to be saved by the application outside of zlib. 677 678 deflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the 679 stream state is inconsistent. 680 */ 681 682 ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest, 683 z_streamp source)); 684 /* 685 Sets the destination stream as a complete copy of the source stream. 686 687 This function can be useful when several compression strategies will be 688 tried, for example when there are several ways of pre-processing the input 689 data with a filter. The streams that will be discarded should then be freed 690 by calling deflateEnd. Note that deflateCopy duplicates the internal 691 compression state which can be quite large, so this strategy is slow and can 692 consume lots of memory. 693 694 deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not 695 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent 696 (such as zalloc being Z_NULL). msg is left unchanged in both source and 697 destination. 698 */ 699 700 ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm)); 701 /* 702 This function is equivalent to deflateEnd followed by deflateInit, but 703 does not free and reallocate the internal compression state. The stream 704 will leave the compression level and any other attributes that may have been 705 set unchanged. 706 707 deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source 708 stream state was inconsistent (such as zalloc or state being Z_NULL). 709 */ 710 711 ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm, 712 int level, 713 int strategy)); 714 /* 715 Dynamically update the compression level and compression strategy. The 716 interpretation of level and strategy is as in deflateInit2(). This can be 717 used to switch between compression and straight copy of the input data, or 718 to switch to a different kind of input data requiring a different strategy. 719 If the compression approach (which is a function of the level) or the 720 strategy is changed, and if any input has been consumed in a previous 721 deflate() call, then the input available so far is compressed with the old 722 level and strategy using deflate(strm, Z_BLOCK). There are three approaches 723 for the compression levels 0, 1..3, and 4..9 respectively. The new level 724 and strategy will take effect at the next call of deflate(). 725 726 If a deflate(strm, Z_BLOCK) is performed by deflateParams(), and it does 727 not have enough output space to complete, then the parameter change will not 728 take effect. In this case, deflateParams() can be called again with the 729 same parameters and more output space to try again. 730 731 In order to assure a change in the parameters on the first try, the 732 deflate stream should be flushed using deflate() with Z_BLOCK or other flush 733 request until strm.avail_out is not zero, before calling deflateParams(). 734 Then no more input data should be provided before the deflateParams() call. 735 If this is done, the old level and strategy will be applied to the data 736 compressed before deflateParams(), and the new level and strategy will be 737 applied to the the data compressed after deflateParams(). 738 739 deflateParams returns Z_OK on success, Z_STREAM_ERROR if the source stream 740 state was inconsistent or if a parameter was invalid, or Z_BUF_ERROR if 741 there was not enough output space to complete the compression of the 742 available input data before a change in the strategy or approach. Note that 743 in the case of a Z_BUF_ERROR, the parameters are not changed. A return 744 value of Z_BUF_ERROR is not fatal, in which case deflateParams() can be 745 retried with more output space. 746 */ 747 748 ZEXTERN int ZEXPORT deflateTune OF((z_streamp strm, 749 int good_length, 750 int max_lazy, 751 int nice_length, 752 int max_chain)); 753 /* 754 Fine tune deflate's internal compression parameters. This should only be 755 used by someone who understands the algorithm used by zlib's deflate for 756 searching for the best matching string, and even then only by the most 757 fanatic optimizer trying to squeeze out the last compressed bit for their 758 specific input data. Read the deflate.c source code for the meaning of the 759 max_lazy, good_length, nice_length, and max_chain parameters. 760 761 deflateTune() can be called after deflateInit() or deflateInit2(), and 762 returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream. 763 */ 764 765 ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm, 766 uLong sourceLen)); 767 /* 768 deflateBound() returns an upper bound on the compressed size after 769 deflation of sourceLen bytes. It must be called after deflateInit() or 770 deflateInit2(), and after deflateSetHeader(), if used. This would be used 771 to allocate an output buffer for deflation in a single pass, and so would be 772 called before deflate(). If that first deflate() call is provided the 773 sourceLen input bytes, an output buffer allocated to the size returned by 774 deflateBound(), and the flush value Z_FINISH, then deflate() is guaranteed 775 to return Z_STREAM_END. Note that it is possible for the compressed size to 776 be larger than the value returned by deflateBound() if flush options other 777 than Z_FINISH or Z_NO_FLUSH are used. 778 */ 779 780 ZEXTERN int ZEXPORT deflatePending OF((z_streamp strm, 781 unsigned *pending, 782 int *bits)); 783 /* 784 deflatePending() returns the number of bytes and bits of output that have 785 been generated, but not yet provided in the available output. The bytes not 786 provided would be due to the available output space having being consumed. 787 The number of bits of output not provided are between 0 and 7, where they 788 await more bits to join them in order to fill out a full byte. If pending 789 or bits are Z_NULL, then those values are not set. 790 791 deflatePending returns Z_OK if success, or Z_STREAM_ERROR if the source 792 stream state was inconsistent. 793 */ 794 795 ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm, 796 int bits, 797 int value)); 798 /* 799 deflatePrime() inserts bits in the deflate output stream. The intent 800 is that this function is used to start off the deflate output with the bits 801 leftover from a previous deflate stream when appending to it. As such, this 802 function can only be used for raw deflate, and must be used before the first 803 deflate() call after a deflateInit2() or deflateReset(). bits must be less 804 than or equal to 16, and that many of the least significant bits of value 805 will be inserted in the output. 806 807 deflatePrime returns Z_OK if success, Z_BUF_ERROR if there was not enough 808 room in the internal buffer to insert the bits, or Z_STREAM_ERROR if the 809 source stream state was inconsistent. 810 */ 811 812 ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm, 813 gz_headerp head)); 814 /* 815 deflateSetHeader() provides gzip header information for when a gzip 816 stream is requested by deflateInit2(). deflateSetHeader() may be called 817 after deflateInit2() or deflateReset() and before the first call of 818 deflate(). The text, time, os, extra field, name, and comment information 819 in the provided gz_header structure are written to the gzip header (xflag is 820 ignored -- the extra flags are set according to the compression level). The 821 caller must assure that, if not Z_NULL, name and comment are terminated with 822 a zero byte, and that if extra is not Z_NULL, that extra_len bytes are 823 available there. If hcrc is true, a gzip header crc is included. Note that 824 the current versions of the command-line version of gzip (up through version 825 1.3.x) do not support header crc's, and will report that it is a "multi-part 826 gzip file" and give up. 827 828 If deflateSetHeader is not used, the default gzip header has text false, 829 the time set to zero, and os set to 255, with no extra, name, or comment 830 fields. The gzip header is returned to the default state by deflateReset(). 831 832 deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source 833 stream state was inconsistent. 834 */ 835 836 /* 837 ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm, 838 int windowBits)); 839 840 This is another version of inflateInit with an extra parameter. The 841 fields next_in, avail_in, zalloc, zfree and opaque must be initialized 842 before by the caller. 843 844 The windowBits parameter is the base two logarithm of the maximum window 845 size (the size of the history buffer). It should be in the range 8..15 for 846 this version of the library. The default value is 15 if inflateInit is used 847 instead. windowBits must be greater than or equal to the windowBits value 848 provided to deflateInit2() while compressing, or it must be equal to 15 if 849 deflateInit2() was not used. If a compressed stream with a larger window 850 size is given as input, inflate() will return with the error code 851 Z_DATA_ERROR instead of trying to allocate a larger window. 852 853 windowBits can also be zero to request that inflate use the window size in 854 the zlib header of the compressed stream. 855 856 windowBits can also be -8..-15 for raw inflate. In this case, -windowBits 857 determines the window size. inflate() will then process raw deflate data, 858 not looking for a zlib or gzip header, not generating a check value, and not 859 looking for any check values for comparison at the end of the stream. This 860 is for use with other formats that use the deflate compressed data format 861 such as zip. Those formats provide their own check values. If a custom 862 format is developed using the raw deflate format for compressed data, it is 863 recommended that a check value such as an Adler-32 or a CRC-32 be applied to 864 the uncompressed data as is done in the zlib, gzip, and zip formats. For 865 most applications, the zlib format should be used as is. Note that comments 866 above on the use in deflateInit2() applies to the magnitude of windowBits. 867 868 windowBits can also be greater than 15 for optional gzip decoding. Add 869 32 to windowBits to enable zlib and gzip decoding with automatic header 870 detection, or add 16 to decode only the gzip format (the zlib format will 871 return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is a 872 CRC-32 instead of an Adler-32. Unlike the gunzip utility and gzread() (see 873 below), inflate() will not automatically decode concatenated gzip streams. 874 inflate() will return Z_STREAM_END at the end of the gzip stream. The state 875 would need to be reset to continue decoding a subsequent gzip stream. 876 877 inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 878 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the 879 version assumed by the caller, or Z_STREAM_ERROR if the parameters are 880 invalid, such as a null pointer to the structure. msg is set to null if 881 there is no error message. inflateInit2 does not perform any decompression 882 apart from possibly reading the zlib header if present: actual decompression 883 will be done by inflate(). (So next_in and avail_in may be modified, but 884 next_out and avail_out are unused and unchanged.) The current implementation 885 of inflateInit2() does not process any header information -- that is 886 deferred until inflate() is called. 887 */ 888 889 ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm, 890 const Bytef *dictionary, 891 uInt dictLength)); 892 /* 893 Initializes the decompression dictionary from the given uncompressed byte 894 sequence. This function must be called immediately after a call of inflate, 895 if that call returned Z_NEED_DICT. The dictionary chosen by the compressor 896 can be determined from the Adler-32 value returned by that call of inflate. 897 The compressor and decompressor must use exactly the same dictionary (see 898 deflateSetDictionary). For raw inflate, this function can be called at any 899 time to set the dictionary. If the provided dictionary is smaller than the 900 window and there is already data in the window, then the provided dictionary 901 will amend what's there. The application must insure that the dictionary 902 that was used for compression is provided. 903 904 inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a 905 parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is 906 inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the 907 expected one (incorrect Adler-32 value). inflateSetDictionary does not 908 perform any decompression: this will be done by subsequent calls of 909 inflate(). 910 */ 911 912 ZEXTERN int ZEXPORT inflateGetDictionary OF((z_streamp strm, 913 Bytef *dictionary, 914 uInt *dictLength)); 915 /* 916 Returns the sliding dictionary being maintained by inflate. dictLength is 917 set to the number of bytes in the dictionary, and that many bytes are copied 918 to dictionary. dictionary must have enough space, where 32768 bytes is 919 always enough. If inflateGetDictionary() is called with dictionary equal to 920 Z_NULL, then only the dictionary length is returned, and nothing is copied. 921 Similary, if dictLength is Z_NULL, then it is not set. 922 923 inflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the 924 stream state is inconsistent. 925 */ 926 927 ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm)); 928 /* 929 Skips invalid compressed data until a possible full flush point (see above 930 for the description of deflate with Z_FULL_FLUSH) can be found, or until all 931 available input is skipped. No output is provided. 932 933 inflateSync searches for a 00 00 FF FF pattern in the compressed data. 934 All full flush points have this pattern, but not all occurrences of this 935 pattern are full flush points. 936 937 inflateSync returns Z_OK if a possible full flush point has been found, 938 Z_BUF_ERROR if no more input was provided, Z_DATA_ERROR if no flush point 939 has been found, or Z_STREAM_ERROR if the stream structure was inconsistent. 940 In the success case, the application may save the current current value of 941 total_in which indicates where valid compressed data was found. In the 942 error case, the application may repeatedly call inflateSync, providing more 943 input each time, until success or end of the input data. 944 */ 945 946 ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest, 947 z_streamp source)); 948 /* 949 Sets the destination stream as a complete copy of the source stream. 950 951 This function can be useful when randomly accessing a large stream. The 952 first pass through the stream can periodically record the inflate state, 953 allowing restarting inflate at those points when randomly accessing the 954 stream. 955 956 inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not 957 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent 958 (such as zalloc being Z_NULL). msg is left unchanged in both source and 959 destination. 960 */ 961 962 ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm)); 963 /* 964 This function is equivalent to inflateEnd followed by inflateInit, 965 but does not free and reallocate the internal decompression state. The 966 stream will keep attributes that may have been set by inflateInit2. 967 968 inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source 969 stream state was inconsistent (such as zalloc or state being Z_NULL). 970 */ 971 972 ZEXTERN int ZEXPORT inflateReset2 OF((z_streamp strm, 973 int windowBits)); 974 /* 975 This function is the same as inflateReset, but it also permits changing 976 the wrap and window size requests. The windowBits parameter is interpreted 977 the same as it is for inflateInit2. If the window size is changed, then the 978 memory allocated for the window is freed, and the window will be reallocated 979 by inflate() if needed. 980 981 inflateReset2 returns Z_OK if success, or Z_STREAM_ERROR if the source 982 stream state was inconsistent (such as zalloc or state being Z_NULL), or if 983 the windowBits parameter is invalid. 984 */ 985 986 ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm, 987 int bits, 988 int value)); 989 /* 990 This function inserts bits in the inflate input stream. The intent is 991 that this function is used to start inflating at a bit position in the 992 middle of a byte. The provided bits will be used before any bytes are used 993 from next_in. This function should only be used with raw inflate, and 994 should be used before the first inflate() call after inflateInit2() or 995 inflateReset(). bits must be less than or equal to 16, and that many of the 996 least significant bits of value will be inserted in the input. 997 998 If bits is negative, then the input stream bit buffer is emptied. Then 999 inflatePrime() can be called again to put bits in the buffer. This is used 1000 to clear out bits leftover after feeding inflate a block description prior 1001 to feeding inflate codes. 1002 1003 inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source 1004 stream state was inconsistent. 1005 */ 1006 1007 ZEXTERN long ZEXPORT inflateMark OF((z_streamp strm)); 1008 /* 1009 This function returns two values, one in the lower 16 bits of the return 1010 value, and the other in the remaining upper bits, obtained by shifting the 1011 return value down 16 bits. If the upper value is -1 and the lower value is 1012 zero, then inflate() is currently decoding information outside of a block. 1013 If the upper value is -1 and the lower value is non-zero, then inflate is in 1014 the middle of a stored block, with the lower value equaling the number of 1015 bytes from the input remaining to copy. If the upper value is not -1, then 1016 it is the number of bits back from the current bit position in the input of 1017 the code (literal or length/distance pair) currently being processed. In 1018 that case the lower value is the number of bytes already emitted for that 1019 code. 1020 1021 A code is being processed if inflate is waiting for more input to complete 1022 decoding of the code, or if it has completed decoding but is waiting for 1023 more output space to write the literal or match data. 1024 1025 inflateMark() is used to mark locations in the input data for random 1026 access, which may be at bit positions, and to note those cases where the 1027 output of a code may span boundaries of random access blocks. The current 1028 location in the input stream can be determined from avail_in and data_type 1029 as noted in the description for the Z_BLOCK flush parameter for inflate. 1030 1031 inflateMark returns the value noted above, or -65536 if the provided 1032 source stream state was inconsistent. 1033 */ 1034 1035 ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm, 1036 gz_headerp head)); 1037 /* 1038 inflateGetHeader() requests that gzip header information be stored in the 1039 provided gz_header structure. inflateGetHeader() may be called after 1040 inflateInit2() or inflateReset(), and before the first call of inflate(). 1041 As inflate() processes the gzip stream, head->done is zero until the header 1042 is completed, at which time head->done is set to one. If a zlib stream is 1043 being decoded, then head->done is set to -1 to indicate that there will be 1044 no gzip header information forthcoming. Note that Z_BLOCK or Z_TREES can be 1045 used to force inflate() to return immediately after header processing is 1046 complete and before any actual data is decompressed. 1047 1048 The text, time, xflags, and os fields are filled in with the gzip header 1049 contents. hcrc is set to true if there is a header CRC. (The header CRC 1050 was valid if done is set to one.) If extra is not Z_NULL, then extra_max 1051 contains the maximum number of bytes to write to extra. Once done is true, 1052 extra_len contains the actual extra field length, and extra contains the 1053 extra field, or that field truncated if extra_max is less than extra_len. 1054 If name is not Z_NULL, then up to name_max characters are written there, 1055 terminated with a zero unless the length is greater than name_max. If 1056 comment is not Z_NULL, then up to comm_max characters are written there, 1057 terminated with a zero unless the length is greater than comm_max. When any 1058 of extra, name, or comment are not Z_NULL and the respective field is not 1059 present in the header, then that field is set to Z_NULL to signal its 1060 absence. This allows the use of deflateSetHeader() with the returned 1061 structure to duplicate the header. However if those fields are set to 1062 allocated memory, then the application will need to save those pointers 1063 elsewhere so that they can be eventually freed. 1064 1065 If inflateGetHeader is not used, then the header information is simply 1066 discarded. The header is always checked for validity, including the header 1067 CRC if present. inflateReset() will reset the process to discard the header 1068 information. The application would need to call inflateGetHeader() again to 1069 retrieve the header from the next gzip stream. 1070 1071 inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source 1072 stream state was inconsistent. 1073 */ 1074 1075 /* 1076 ZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits, 1077 unsigned char FAR *window)); 1078 1079 Initialize the internal stream state for decompression using inflateBack() 1080 calls. The fields zalloc, zfree and opaque in strm must be initialized 1081 before the call. If zalloc and zfree are Z_NULL, then the default library- 1082 derived memory allocation routines are used. windowBits is the base two 1083 logarithm of the window size, in the range 8..15. window is a caller 1084 supplied buffer of that size. Except for special applications where it is 1085 assured that deflate was used with small window sizes, windowBits must be 15 1086 and a 32K byte window must be supplied to be able to decompress general 1087 deflate streams. 1088 1089 See inflateBack() for the usage of these routines. 1090 1091 inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of 1092 the parameters are invalid, Z_MEM_ERROR if the internal state could not be 1093 allocated, or Z_VERSION_ERROR if the version of the library does not match 1094 the version of the header file. 1095 */ 1096 1097 typedef unsigned (*in_func) OF((void FAR *, 1098 z_const unsigned char FAR * FAR *)); 1099 typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned)); 1100 1101 ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm, 1102 in_func in, void FAR *in_desc, 1103 out_func out, void FAR *out_desc)); 1104 /* 1105 inflateBack() does a raw inflate with a single call using a call-back 1106 interface for input and output. This is potentially more efficient than 1107 inflate() for file i/o applications, in that it avoids copying between the 1108 output and the sliding window by simply making the window itself the output 1109 buffer. inflate() can be faster on modern CPUs when used with large 1110 buffers. inflateBack() trusts the application to not change the output 1111 buffer passed by the output function, at least until inflateBack() returns. 1112 1113 inflateBackInit() must be called first to allocate the internal state 1114 and to initialize the state with the user-provided window buffer. 1115 inflateBack() may then be used multiple times to inflate a complete, raw 1116 deflate stream with each call. inflateBackEnd() is then called to free the 1117 allocated state. 1118 1119 A raw deflate stream is one with no zlib or gzip header or trailer. 1120 This routine would normally be used in a utility that reads zip or gzip 1121 files and writes out uncompressed files. The utility would decode the 1122 header and process the trailer on its own, hence this routine expects only 1123 the raw deflate stream to decompress. This is different from the default 1124 behavior of inflate(), which expects a zlib header and trailer around the 1125 deflate stream. 1126 1127 inflateBack() uses two subroutines supplied by the caller that are then 1128 called by inflateBack() for input and output. inflateBack() calls those 1129 routines until it reads a complete deflate stream and writes out all of the 1130 uncompressed data, or until it encounters an error. The function's 1131 parameters and return types are defined above in the in_func and out_func 1132 typedefs. inflateBack() will call in(in_desc, &buf) which should return the 1133 number of bytes of provided input, and a pointer to that input in buf. If 1134 there is no input available, in() must return zero -- buf is ignored in that 1135 case -- and inflateBack() will return a buffer error. inflateBack() will 1136 call out(out_desc, buf, len) to write the uncompressed data buf[0..len-1]. 1137 out() should return zero on success, or non-zero on failure. If out() 1138 returns non-zero, inflateBack() will return with an error. Neither in() nor 1139 out() are permitted to change the contents of the window provided to 1140 inflateBackInit(), which is also the buffer that out() uses to write from. 1141 The length written by out() will be at most the window size. Any non-zero 1142 amount of input may be provided by in(). 1143 1144 For convenience, inflateBack() can be provided input on the first call by 1145 setting strm->next_in and strm->avail_in. If that input is exhausted, then 1146 in() will be called. Therefore strm->next_in must be initialized before 1147 calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called 1148 immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in 1149 must also be initialized, and then if strm->avail_in is not zero, input will 1150 initially be taken from strm->next_in[0 .. strm->avail_in - 1]. 1151 1152 The in_desc and out_desc parameters of inflateBack() is passed as the 1153 first parameter of in() and out() respectively when they are called. These 1154 descriptors can be optionally used to pass any information that the caller- 1155 supplied in() and out() functions need to do their job. 1156 1157 On return, inflateBack() will set strm->next_in and strm->avail_in to 1158 pass back any unused input that was provided by the last in() call. The 1159 return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR 1160 if in() or out() returned an error, Z_DATA_ERROR if there was a format error 1161 in the deflate stream (in which case strm->msg is set to indicate the nature 1162 of the error), or Z_STREAM_ERROR if the stream was not properly initialized. 1163 In the case of Z_BUF_ERROR, an input or output error can be distinguished 1164 using strm->next_in which will be Z_NULL only if in() returned an error. If 1165 strm->next_in is not Z_NULL, then the Z_BUF_ERROR was due to out() returning 1166 non-zero. (in() will always be called before out(), so strm->next_in is 1167 assured to be defined if out() returns non-zero.) Note that inflateBack() 1168 cannot return Z_OK. 1169 */ 1170 1171 ZEXTERN int ZEXPORT inflateBackEnd OF((z_streamp strm)); 1172 /* 1173 All memory allocated by inflateBackInit() is freed. 1174 1175 inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream 1176 state was inconsistent. 1177 */ 1178 1179 ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void)); 1180 /* Return flags indicating compile-time options. 1181 1182 Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other: 1183 1.0: size of uInt 1184 3.2: size of uLong 1185 5.4: size of voidpf (pointer) 1186 7.6: size of z_off_t 1187 1188 Compiler, assembler, and debug options: 1189 8: ZLIB_DEBUG 1190 9: ASMV or ASMINF -- use ASM code 1191 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention 1192 11: 0 (reserved) 1193 1194 One-time table building (smaller code, but not thread-safe if true): 1195 12: BUILDFIXED -- build static block decoding tables when needed 1196 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed 1197 14,15: 0 (reserved) 1198 1199 Library content (indicates missing functionality): 1200 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking 1201 deflate code when not needed) 1202 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect 1203 and decode gzip streams (to avoid linking crc code) 1204 18-19: 0 (reserved) 1205 1206 Operation variations (changes in library functionality): 1207 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate 1208 21: FASTEST -- deflate algorithm with only one, lowest compression level 1209 22,23: 0 (reserved) 1210 1211 The sprintf variant used by gzprintf (zero is best): 1212 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format 1213 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure! 1214 26: 0 = returns value, 1 = void -- 1 means inferred string length returned 1215 1216 Remainder: 1217 27-31: 0 (reserved) 1218 */ 1219 1220 #ifndef Z_SOLO 1221 1222 /* utility functions */ 1223 1224 /* 1225 The following utility functions are implemented on top of the basic 1226 stream-oriented functions. To simplify the interface, some default options 1227 are assumed (compression level and memory usage, standard memory allocation 1228 functions). The source code of these utility functions can be modified if 1229 you need special options. 1230 */ 1231 1232 ZEXTERN int ZEXPORT compress OF((Bytef *dest, uLongf *destLen, 1233 const Bytef *source, uLong sourceLen)); 1234 /* 1235 Compresses the source buffer into the destination buffer. sourceLen is 1236 the byte length of the source buffer. Upon entry, destLen is the total size 1237 of the destination buffer, which must be at least the value returned by 1238 compressBound(sourceLen). Upon exit, destLen is the actual size of the 1239 compressed data. compress() is equivalent to compress2() with a level 1240 parameter of Z_DEFAULT_COMPRESSION. 1241 1242 compress returns Z_OK if success, Z_MEM_ERROR if there was not 1243 enough memory, Z_BUF_ERROR if there was not enough room in the output 1244 buffer. 1245 */ 1246 1247 ZEXTERN int ZEXPORT compress2 OF((Bytef *dest, uLongf *destLen, 1248 const Bytef *source, uLong sourceLen, 1249 int level)); 1250 /* 1251 Compresses the source buffer into the destination buffer. The level 1252 parameter has the same meaning as in deflateInit. sourceLen is the byte 1253 length of the source buffer. Upon entry, destLen is the total size of the 1254 destination buffer, which must be at least the value returned by 1255 compressBound(sourceLen). Upon exit, destLen is the actual size of the 1256 compressed data. 1257 1258 compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 1259 memory, Z_BUF_ERROR if there was not enough room in the output buffer, 1260 Z_STREAM_ERROR if the level parameter is invalid. 1261 */ 1262 1263 ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen)); 1264 /* 1265 compressBound() returns an upper bound on the compressed size after 1266 compress() or compress2() on sourceLen bytes. It would be used before a 1267 compress() or compress2() call to allocate the destination buffer. 1268 */ 1269 1270 ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen, 1271 const Bytef *source, uLong sourceLen)); 1272 /* 1273 Decompresses the source buffer into the destination buffer. sourceLen is 1274 the byte length of the source buffer. Upon entry, destLen is the total size 1275 of the destination buffer, which must be large enough to hold the entire 1276 uncompressed data. (The size of the uncompressed data must have been saved 1277 previously by the compressor and transmitted to the decompressor by some 1278 mechanism outside the scope of this compression library.) Upon exit, destLen 1279 is the actual size of the uncompressed data. 1280 1281 uncompress returns Z_OK if success, Z_MEM_ERROR if there was not 1282 enough memory, Z_BUF_ERROR if there was not enough room in the output 1283 buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete. In 1284 the case where there is not enough room, uncompress() will fill the output 1285 buffer with the uncompressed data up to that point. 1286 */ 1287 1288 ZEXTERN int ZEXPORT uncompress2 OF((Bytef *dest, uLongf *destLen, 1289 const Bytef *source, uLong *sourceLen)); 1290 /* 1291 Same as uncompress, except that sourceLen is a pointer, where the 1292 length of the source is *sourceLen. On return, *sourceLen is the number of 1293 source bytes consumed. 1294 */ 1295 1296 /* gzip file access functions */ 1297 1298 /* 1299 This library supports reading and writing files in gzip (.gz) format with 1300 an interface similar to that of stdio, using the functions that start with 1301 "gz". The gzip format is different from the zlib format. gzip is a gzip 1302 wrapper, documented in RFC 1952, wrapped around a deflate stream. 1303 */ 1304 1305 typedef struct gzFile_s *gzFile; /* semi-opaque gzip file descriptor */ 1306 1307 /* 1308 ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode)); 1309 1310 Opens a gzip (.gz) file for reading or writing. The mode parameter is as 1311 in fopen ("rb" or "wb") but can also include a compression level ("wb9") or 1312 a strategy: 'f' for filtered data as in "wb6f", 'h' for Huffman-only 1313 compression as in "wb1h", 'R' for run-length encoding as in "wb1R", or 'F' 1314 for fixed code compression as in "wb9F". (See the description of 1315 deflateInit2 for more information about the strategy parameter.) 'T' will 1316 request transparent writing or appending with no compression and not using 1317 the gzip format. 1318 1319 "a" can be used instead of "w" to request that the gzip stream that will 1320 be written be appended to the file. "+" will result in an error, since 1321 reading and writing to the same gzip file is not supported. The addition of 1322 "x" when writing will create the file exclusively, which fails if the file 1323 already exists. On systems that support it, the addition of "e" when 1324 reading or writing will set the flag to close the file on an execve() call. 1325 1326 These functions, as well as gzip, will read and decode a sequence of gzip 1327 streams in a file. The append function of gzopen() can be used to create 1328 such a file. (Also see gzflush() for another way to do this.) When 1329 appending, gzopen does not test whether the file begins with a gzip stream, 1330 nor does it look for the end of the gzip streams to begin appending. gzopen 1331 will simply append a gzip stream to the existing file. 1332 1333 gzopen can be used to read a file which is not in gzip format; in this 1334 case gzread will directly read from the file without decompression. When 1335 reading, this will be detected automatically by looking for the magic two- 1336 byte gzip header. 1337 1338 gzopen returns NULL if the file could not be opened, if there was 1339 insufficient memory to allocate the gzFile state, or if an invalid mode was 1340 specified (an 'r', 'w', or 'a' was not provided, or '+' was provided). 1341 errno can be checked to determine if the reason gzopen failed was that the 1342 file could not be opened. 1343 */ 1344 1345 ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode)); 1346 /* 1347 gzdopen associates a gzFile with the file descriptor fd. File descriptors 1348 are obtained from calls like open, dup, creat, pipe or fileno (if the file 1349 has been previously opened with fopen). The mode parameter is as in gzopen. 1350 1351 The next call of gzclose on the returned gzFile will also close the file 1352 descriptor fd, just like fclose(fdopen(fd, mode)) closes the file descriptor 1353 fd. If you want to keep fd open, use fd = dup(fd_keep); gz = gzdopen(fd, 1354 mode);. The duplicated descriptor should be saved to avoid a leak, since 1355 gzdopen does not close fd if it fails. If you are using fileno() to get the 1356 file descriptor from a FILE *, then you will have to use dup() to avoid 1357 double-close()ing the file descriptor. Both gzclose() and fclose() will 1358 close the associated file descriptor, so they need to have different file 1359 descriptors. 1360 1361 gzdopen returns NULL if there was insufficient memory to allocate the 1362 gzFile state, if an invalid mode was specified (an 'r', 'w', or 'a' was not 1363 provided, or '+' was provided), or if fd is -1. The file descriptor is not 1364 used until the next gz* read, write, seek, or close operation, so gzdopen 1365 will not detect if fd is invalid (unless fd is -1). 1366 */ 1367 1368 ZEXTERN int ZEXPORT gzbuffer OF((gzFile file, unsigned size)); 1369 /* 1370 Set the internal buffer size used by this library's functions. The 1371 default buffer size is 8192 bytes. This function must be called after 1372 gzopen() or gzdopen(), and before any other calls that read or write the 1373 file. The buffer memory allocation is always deferred to the first read or 1374 write. Three times that size in buffer space is allocated. A larger buffer 1375 size of, for example, 64K or 128K bytes will noticeably increase the speed 1376 of decompression (reading). 1377 1378 The new buffer size also affects the maximum length for gzprintf(). 1379 1380 gzbuffer() returns 0 on success, or -1 on failure, such as being called 1381 too late. 1382 */ 1383 1384 ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy)); 1385 /* 1386 Dynamically update the compression level or strategy. See the description 1387 of deflateInit2 for the meaning of these parameters. Previously provided 1388 data is flushed before the parameter change. 1389 1390 gzsetparams returns Z_OK if success, Z_STREAM_ERROR if the file was not 1391 opened for writing, Z_ERRNO if there is an error writing the flushed data, 1392 or Z_MEM_ERROR if there is a memory allocation error. 1393 */ 1394 1395 ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len)); 1396 /* 1397 Reads the given number of uncompressed bytes from the compressed file. If 1398 the input file is not in gzip format, gzread copies the given number of 1399 bytes into the buffer directly from the file. 1400 1401 After reaching the end of a gzip stream in the input, gzread will continue 1402 to read, looking for another gzip stream. Any number of gzip streams may be 1403 concatenated in the input file, and will all be decompressed by gzread(). 1404 If something other than a gzip stream is encountered after a gzip stream, 1405 that remaining trailing garbage is ignored (and no error is returned). 1406 1407 gzread can be used to read a gzip file that is being concurrently written. 1408 Upon reaching the end of the input, gzread will return with the available 1409 data. If the error code returned by gzerror is Z_OK or Z_BUF_ERROR, then 1410 gzclearerr can be used to clear the end of file indicator in order to permit 1411 gzread to be tried again. Z_OK indicates that a gzip stream was completed 1412 on the last gzread. Z_BUF_ERROR indicates that the input file ended in the 1413 middle of a gzip stream. Note that gzread does not return -1 in the event 1414 of an incomplete gzip stream. This error is deferred until gzclose(), which 1415 will return Z_BUF_ERROR if the last gzread ended in the middle of a gzip 1416 stream. Alternatively, gzerror can be used before gzclose to detect this 1417 case. 1418 1419 gzread returns the number of uncompressed bytes actually read, less than 1420 len for end of file, or -1 for error. If len is too large to fit in an int, 1421 then nothing is read, -1 is returned, and the error state is set to 1422 Z_STREAM_ERROR. 1423 */ 1424 1425 ZEXTERN z_size_t ZEXPORT gzfread OF((voidp buf, z_size_t size, z_size_t nitems, 1426 gzFile file)); 1427 /* 1428 Read up to nitems items of size size from file to buf, otherwise operating 1429 as gzread() does. This duplicates the interface of stdio's fread(), with 1430 size_t request and return types. If the library defines size_t, then 1431 z_size_t is identical to size_t. If not, then z_size_t is an unsigned 1432 integer type that can contain a pointer. 1433 1434 gzfread() returns the number of full items read of size size, or zero if 1435 the end of the file was reached and a full item could not be read, or if 1436 there was an error. gzerror() must be consulted if zero is returned in 1437 order to determine if there was an error. If the multiplication of size and 1438 nitems overflows, i.e. the product does not fit in a z_size_t, then nothing 1439 is read, zero is returned, and the error state is set to Z_STREAM_ERROR. 1440 1441 In the event that the end of file is reached and only a partial item is 1442 available at the end, i.e. the remaining uncompressed data length is not a 1443 multiple of size, then the final partial item is nevetheless read into buf 1444 and the end-of-file flag is set. The length of the partial item read is not 1445 provided, but could be inferred from the result of gztell(). This behavior 1446 is the same as the behavior of fread() implementations in common libraries, 1447 but it prevents the direct use of gzfread() to read a concurrently written 1448 file, reseting and retrying on end-of-file, when size is not 1. 1449 */ 1450 1451 ZEXTERN int ZEXPORT gzwrite OF((gzFile file, 1452 voidpc buf, unsigned len)); 1453 /* 1454 Writes the given number of uncompressed bytes into the compressed file. 1455 gzwrite returns the number of uncompressed bytes written or 0 in case of 1456 error. 1457 */ 1458 1459 ZEXTERN z_size_t ZEXPORT gzfwrite OF((voidpc buf, z_size_t size, 1460 z_size_t nitems, gzFile file)); 1461 /* 1462 gzfwrite() writes nitems items of size size from buf to file, duplicating 1463 the interface of stdio's fwrite(), with size_t request and return types. If 1464 the library defines size_t, then z_size_t is identical to size_t. If not, 1465 then z_size_t is an unsigned integer type that can contain a pointer. 1466 1467 gzfwrite() returns the number of full items written of size size, or zero 1468 if there was an error. If the multiplication of size and nitems overflows, 1469 i.e. the product does not fit in a z_size_t, then nothing is written, zero 1470 is returned, and the error state is set to Z_STREAM_ERROR. 1471 */ 1472 1473 ZEXTERN int ZEXPORTVA gzprintf Z_ARG((gzFile file, const char *format, ...)); 1474 /* 1475 Converts, formats, and writes the arguments to the compressed file under 1476 control of the format string, as in fprintf. gzprintf returns the number of 1477 uncompressed bytes actually written, or a negative zlib error code in case 1478 of error. The number of uncompressed bytes written is limited to 8191, or 1479 one less than the buffer size given to gzbuffer(). The caller should assure 1480 that this limit is not exceeded. If it is exceeded, then gzprintf() will 1481 return an error (0) with nothing written. In this case, there may also be a 1482 buffer overflow with unpredictable consequences, which is possible only if 1483 zlib was compiled with the insecure functions sprintf() or vsprintf() 1484 because the secure snprintf() or vsnprintf() functions were not available. 1485 This can be determined using zlibCompileFlags(). 1486 */ 1487 1488 ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s)); 1489 /* 1490 Writes the given null-terminated string to the compressed file, excluding 1491 the terminating null character. 1492 1493 gzputs returns the number of characters written, or -1 in case of error. 1494 */ 1495 1496 ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len)); 1497 /* 1498 Reads bytes from the compressed file until len-1 characters are read, or a 1499 newline character is read and transferred to buf, or an end-of-file 1500 condition is encountered. If any characters are read or if len == 1, the 1501 string is terminated with a null character. If no characters are read due 1502 to an end-of-file or len < 1, then the buffer is left untouched. 1503 1504 gzgets returns buf which is a null-terminated string, or it returns NULL 1505 for end-of-file or in case of error. If there was an error, the contents at 1506 buf are indeterminate. 1507 */ 1508 1509 ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c)); 1510 /* 1511 Writes c, converted to an unsigned char, into the compressed file. gzputc 1512 returns the value that was written, or -1 in case of error. 1513 */ 1514 1515 ZEXTERN int ZEXPORT gzgetc OF((gzFile file)); 1516 /* 1517 Reads one byte from the compressed file. gzgetc returns this byte or -1 1518 in case of end of file or error. This is implemented as a macro for speed. 1519 As such, it does not do all of the checking the other functions do. I.e. 1520 it does not check to see if file is NULL, nor whether the structure file 1521 points to has been clobbered or not. 1522 */ 1523 1524 ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file)); 1525 /* 1526 Push one character back onto the stream to be read as the first character 1527 on the next read. At least one character of push-back is allowed. 1528 gzungetc() returns the character pushed, or -1 on failure. gzungetc() will 1529 fail if c is -1, and may fail if a character has been pushed but not read 1530 yet. If gzungetc is used immediately after gzopen or gzdopen, at least the 1531 output buffer size of pushed characters is allowed. (See gzbuffer above.) 1532 The pushed character will be discarded if the stream is repositioned with 1533 gzseek() or gzrewind(). 1534 */ 1535 1536 ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush)); 1537 /* 1538 Flushes all pending output into the compressed file. The parameter flush 1539 is as in the deflate() function. The return value is the zlib error number 1540 (see function gzerror below). gzflush is only permitted when writing. 1541 1542 If the flush parameter is Z_FINISH, the remaining data is written and the 1543 gzip stream is completed in the output. If gzwrite() is called again, a new 1544 gzip stream will be started in the output. gzread() is able to read such 1545 concatenated gzip streams. 1546 1547 gzflush should be called only when strictly necessary because it will 1548 degrade compression if called too often. 1549 */ 1550 1551 /* 1552 ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file, 1553 z_off_t offset, int whence)); 1554 1555 Sets the starting position for the next gzread or gzwrite on the given 1556 compressed file. The offset represents a number of bytes in the 1557 uncompressed data stream. The whence parameter is defined as in lseek(2); 1558 the value SEEK_END is not supported. 1559 1560 If the file is opened for reading, this function is emulated but can be 1561 extremely slow. If the file is opened for writing, only forward seeks are 1562 supported; gzseek then compresses a sequence of zeroes up to the new 1563 starting position. 1564 1565 gzseek returns the resulting offset location as measured in bytes from 1566 the beginning of the uncompressed stream, or -1 in case of error, in 1567 particular if the file is opened for writing and the new starting position 1568 would be before the current position. 1569 */ 1570 1571 ZEXTERN int ZEXPORT gzrewind OF((gzFile file)); 1572 /* 1573 Rewinds the given file. This function is supported only for reading. 1574 1575 gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET) 1576 */ 1577 1578 /* 1579 ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file)); 1580 1581 Returns the starting position for the next gzread or gzwrite on the given 1582 compressed file. This position represents a number of bytes in the 1583 uncompressed data stream, and is zero when starting, even if appending or 1584 reading a gzip stream from the middle of a file using gzdopen(). 1585 1586 gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR) 1587 */ 1588 1589 /* 1590 ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile file)); 1591 1592 Returns the current offset in the file being read or written. This offset 1593 includes the count of bytes that precede the gzip stream, for example when 1594 appending or when using gzdopen() for reading. When reading, the offset 1595 does not include as yet unused buffered input. This information can be used 1596 for a progress indicator. On error, gzoffset() returns -1. 1597 */ 1598 1599 ZEXTERN int ZEXPORT gzeof OF((gzFile file)); 1600 /* 1601 Returns true (1) if the end-of-file indicator has been set while reading, 1602 false (0) otherwise. Note that the end-of-file indicator is set only if the 1603 read tried to go past the end of the input, but came up short. Therefore, 1604 just like feof(), gzeof() may return false even if there is no more data to 1605 read, in the event that the last read request was for the exact number of 1606 bytes remaining in the input file. This will happen if the input file size 1607 is an exact multiple of the buffer size. 1608 1609 If gzeof() returns true, then the read functions will return no more data, 1610 unless the end-of-file indicator is reset by gzclearerr() and the input file 1611 has grown since the previous end of file was detected. 1612 */ 1613 1614 ZEXTERN int ZEXPORT gzdirect OF((gzFile file)); 1615 /* 1616 Returns true (1) if file is being copied directly while reading, or false 1617 (0) if file is a gzip stream being decompressed. 1618 1619 If the input file is empty, gzdirect() will return true, since the input 1620 does not contain a gzip stream. 1621 1622 If gzdirect() is used immediately after gzopen() or gzdopen() it will 1623 cause buffers to be allocated to allow reading the file to determine if it 1624 is a gzip file. Therefore if gzbuffer() is used, it should be called before 1625 gzdirect(). 1626 1627 When writing, gzdirect() returns true (1) if transparent writing was 1628 requested ("wT" for the gzopen() mode), or false (0) otherwise. (Note: 1629 gzdirect() is not needed when writing. Transparent writing must be 1630 explicitly requested, so the application already knows the answer. When 1631 linking statically, using gzdirect() will include all of the zlib code for 1632 gzip file reading and decompression, which may not be desired.) 1633 */ 1634 1635 ZEXTERN int ZEXPORT gzclose OF((gzFile file)); 1636 /* 1637 Flushes all pending output if necessary, closes the compressed file and 1638 deallocates the (de)compression state. Note that once file is closed, you 1639 cannot call gzerror with file, since its structures have been deallocated. 1640 gzclose must not be called more than once on the same file, just as free 1641 must not be called more than once on the same allocation. 1642 1643 gzclose will return Z_STREAM_ERROR if file is not valid, Z_ERRNO on a 1644 file operation error, Z_MEM_ERROR if out of memory, Z_BUF_ERROR if the 1645 last read ended in the middle of a gzip stream, or Z_OK on success. 1646 */ 1647 1648 ZEXTERN int ZEXPORT gzclose_r OF((gzFile file)); 1649 ZEXTERN int ZEXPORT gzclose_w OF((gzFile file)); 1650 /* 1651 Same as gzclose(), but gzclose_r() is only for use when reading, and 1652 gzclose_w() is only for use when writing or appending. The advantage to 1653 using these instead of gzclose() is that they avoid linking in zlib 1654 compression or decompression code that is not used when only reading or only 1655 writing respectively. If gzclose() is used, then both compression and 1656 decompression code will be included the application when linking to a static 1657 zlib library. 1658 */ 1659 1660 ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum)); 1661 /* 1662 Returns the error message for the last error which occurred on the given 1663 compressed file. errnum is set to zlib error number. If an error occurred 1664 in the file system and not in the compression library, errnum is set to 1665 Z_ERRNO and the application may consult errno to get the exact error code. 1666 1667 The application must not modify the returned string. Future calls to 1668 this function may invalidate the previously returned string. If file is 1669 closed, then the string previously returned by gzerror will no longer be 1670 available. 1671 1672 gzerror() should be used to distinguish errors from end-of-file for those 1673 functions above that do not distinguish those cases in their return values. 1674 */ 1675 1676 ZEXTERN void ZEXPORT gzclearerr OF((gzFile file)); 1677 /* 1678 Clears the error and end-of-file flags for file. This is analogous to the 1679 clearerr() function in stdio. This is useful for continuing to read a gzip 1680 file that is being written concurrently. 1681 */ 1682 1683 #endif /* !Z_SOLO */ 1684 1685 /* checksum functions */ 1686 1687 /* 1688 These functions are not related to compression but are exported 1689 anyway because they might be useful in applications using the compression 1690 library. 1691 */ 1692 1693 ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len)); 1694 /* 1695 Update a running Adler-32 checksum with the bytes buf[0..len-1] and 1696 return the updated checksum. If buf is Z_NULL, this function returns the 1697 required initial value for the checksum. 1698 1699 An Adler-32 checksum is almost as reliable as a CRC-32 but can be computed 1700 much faster. 1701 1702 Usage example: 1703 1704 uLong adler = adler32(0L, Z_NULL, 0); 1705 1706 while (read_buffer(buffer, length) != EOF) { 1707 adler = adler32(adler, buffer, length); 1708 } 1709 if (adler != original_adler) error(); 1710 */ 1711 1712 ZEXTERN uLong ZEXPORT adler32_z OF((uLong adler, const Bytef *buf, 1713 z_size_t len)); 1714 /* 1715 Same as adler32(), but with a size_t length. 1716 */ 1717 1718 /* 1719 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong adler1, uLong adler2, 1720 z_off_t len2)); 1721 1722 Combine two Adler-32 checksums into one. For two sequences of bytes, seq1 1723 and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for 1724 each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of 1725 seq1 and seq2 concatenated, requiring only adler1, adler2, and len2. Note 1726 that the z_off_t type (like off_t) is a signed integer. If len2 is 1727 negative, the result has no meaning or utility. 1728 */ 1729 1730 ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len)); 1731 /* 1732 Update a running CRC-32 with the bytes buf[0..len-1] and return the 1733 updated CRC-32. If buf is Z_NULL, this function returns the required 1734 initial value for the crc. Pre- and post-conditioning (one's complement) is 1735 performed within this function so it shouldn't be done by the application. 1736 1737 Usage example: 1738 1739 uLong crc = crc32(0L, Z_NULL, 0); 1740 1741 while (read_buffer(buffer, length) != EOF) { 1742 crc = crc32(crc, buffer, length); 1743 } 1744 if (crc != original_crc) error(); 1745 */ 1746 1747 ZEXTERN uLong ZEXPORT crc32_z OF((uLong adler, const Bytef *buf, 1748 z_size_t len)); 1749 /* 1750 Same as crc32(), but with a size_t length. 1751 */ 1752 1753 /* 1754 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2)); 1755 1756 Combine two CRC-32 check values into one. For two sequences of bytes, 1757 seq1 and seq2 with lengths len1 and len2, CRC-32 check values were 1758 calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32 1759 check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and 1760 len2. 1761 */ 1762 1763 1764 /* various hacks, don't look :) */ 1765 1766 /* deflateInit and inflateInit are macros to allow checking the zlib version 1767 * and the compiler's view of z_stream: 1768 */ 1769 ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level, 1770 const char *version, int stream_size)); 1771 ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm, 1772 const char *version, int stream_size)); 1773 ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method, 1774 int windowBits, int memLevel, 1775 int strategy, const char *version, 1776 int stream_size)); 1777 ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits, 1778 const char *version, int stream_size)); 1779 ZEXTERN int ZEXPORT inflateBackInit_ OF((z_streamp strm, int windowBits, 1780 unsigned char FAR *window, 1781 const char *version, 1782 int stream_size)); 1783 #ifdef Z_PREFIX_SET 1784 # define z_deflateInit(strm, level) \ 1785 deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream)) 1786 # define z_inflateInit(strm) \ 1787 inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream)) 1788 # define z_deflateInit2(strm, level, method, windowBits, memLevel, strategy) \ 1789 deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\ 1790 (strategy), ZLIB_VERSION, (int)sizeof(z_stream)) 1791 # define z_inflateInit2(strm, windowBits) \ 1792 inflateInit2_((strm), (windowBits), ZLIB_VERSION, \ 1793 (int)sizeof(z_stream)) 1794 # define z_inflateBackInit(strm, windowBits, window) \ 1795 inflateBackInit_((strm), (windowBits), (window), \ 1796 ZLIB_VERSION, (int)sizeof(z_stream)) 1797 #else 1798 # define deflateInit(strm, level) \ 1799 deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream)) 1800 # define inflateInit(strm) \ 1801 inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream)) 1802 # define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \ 1803 deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\ 1804 (strategy), ZLIB_VERSION, (int)sizeof(z_stream)) 1805 # define inflateInit2(strm, windowBits) \ 1806 inflateInit2_((strm), (windowBits), ZLIB_VERSION, \ 1807 (int)sizeof(z_stream)) 1808 # define inflateBackInit(strm, windowBits, window) \ 1809 inflateBackInit_((strm), (windowBits), (window), \ 1810 ZLIB_VERSION, (int)sizeof(z_stream)) 1811 #endif 1812 1813 #ifndef Z_SOLO 1814 1815 /* gzgetc() macro and its supporting function and exposed data structure. Note 1816 * that the real internal state is much larger than the exposed structure. 1817 * This abbreviated structure exposes just enough for the gzgetc() macro. The 1818 * user should not mess with these exposed elements, since their names or 1819 * behavior could change in the future, perhaps even capriciously. They can 1820 * only be used by the gzgetc() macro. You have been warned. 1821 */ 1822 struct gzFile_s { 1823 unsigned have; 1824 unsigned char *next; 1825 z_off64_t pos; 1826 }; 1827 ZEXTERN int ZEXPORT gzgetc_ OF((gzFile file)); /* backward compatibility */ 1828 #ifdef Z_PREFIX_SET 1829 # undef z_gzgetc 1830 # define z_gzgetc(g) \ 1831 ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : (gzgetc)(g)) 1832 #else 1833 # define gzgetc(g) \ 1834 ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : (gzgetc)(g)) 1835 #endif 1836 1837 /* provide 64-bit offset functions if _LARGEFILE64_SOURCE defined, and/or 1838 * change the regular functions to 64 bits if _FILE_OFFSET_BITS is 64 (if 1839 * both are true, the application gets the *64 functions, and the regular 1840 * functions are changed to 64 bits) -- in case these are set on systems 1841 * without large file support, _LFS64_LARGEFILE must also be true 1842 */ 1843 #ifdef Z_LARGE64 1844 ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *)); 1845 ZEXTERN z_off64_t ZEXPORT gzseek64 OF((gzFile, z_off64_t, int)); 1846 ZEXTERN z_off64_t ZEXPORT gztell64 OF((gzFile)); 1847 ZEXTERN z_off64_t ZEXPORT gzoffset64 OF((gzFile)); 1848 ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off64_t)); 1849 ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off64_t)); 1850 #endif 1851 1852 #if !defined(ZLIB_INTERNAL) && defined(Z_WANT64) 1853 # ifdef Z_PREFIX_SET 1854 # define z_gzopen z_gzopen64 1855 # define z_gzseek z_gzseek64 1856 # define z_gztell z_gztell64 1857 # define z_gzoffset z_gzoffset64 1858 # define z_adler32_combine z_adler32_combine64 1859 # define z_crc32_combine z_crc32_combine64 1860 # else 1861 # define gzopen gzopen64 1862 # define gzseek gzseek64 1863 # define gztell gztell64 1864 # define gzoffset gzoffset64 1865 # define adler32_combine adler32_combine64 1866 # define crc32_combine crc32_combine64 1867 # endif 1868 # ifndef Z_LARGE64 1869 ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *)); 1870 ZEXTERN z_off_t ZEXPORT gzseek64 OF((gzFile, z_off_t, int)); 1871 ZEXTERN z_off_t ZEXPORT gztell64 OF((gzFile)); 1872 ZEXTERN z_off_t ZEXPORT gzoffset64 OF((gzFile)); 1873 ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off_t)); 1874 ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off_t)); 1875 # endif 1876 #else 1877 ZEXTERN gzFile ZEXPORT gzopen OF((const char *, const char *)); 1878 ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile, z_off_t, int)); 1879 ZEXTERN z_off_t ZEXPORT gztell OF((gzFile)); 1880 ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile)); 1881 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t)); 1882 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t)); 1883 #endif 1884 1885 #else /* Z_SOLO */ 1886 1887 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t)); 1888 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t)); 1889 1890 #endif /* !Z_SOLO */ 1891 1892 /* undocumented functions */ 1893 ZEXTERN const char * ZEXPORT zError OF((int)); 1894 ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp)); 1895 ZEXTERN const z_crc_t FAR * ZEXPORT get_crc_table OF((void)); 1896 ZEXTERN int ZEXPORT inflateUndermine OF((z_streamp, int)); 1897 ZEXTERN int ZEXPORT inflateValidate OF((z_streamp, int)); 1898 ZEXTERN unsigned long ZEXPORT inflateCodesUsed OF ((z_streamp)); 1899 ZEXTERN int ZEXPORT inflateResetKeep OF((z_streamp)); 1900 ZEXTERN int ZEXPORT deflateResetKeep OF((z_streamp)); 1901 #if (defined(_WIN32) || defined(__CYGWIN__)) && !defined(Z_SOLO) 1902 ZEXTERN gzFile ZEXPORT gzopen_w OF((const wchar_t *path, 1903 const char *mode)); 1904 #endif 1905 #if defined(STDC) || defined(Z_HAVE_STDARG_H) 1906 # ifndef Z_SOLO 1907 ZEXTERN int ZEXPORTVA gzvprintf Z_ARG((gzFile file, 1908 const char *format, 1909 va_list va)); 1910 # endif 1911 #endif 1912 1913 #ifdef __cplusplus 1914 } 1915 #endif 1916 1917 #endif /* ZLIB_H */ 1918