modernc.org/cc@v1.0.1/v2/headers/linux_arm/usr/include/zlib.h (about) 1 /* zlib.h -- interface of the 'zlib' general purpose compression library 2 version 1.2.8, April 28th, 2013 3 4 Copyright (C) 1995-2013 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 The data format used by the zlib library is described by RFCs (Request for 26 Comments) 1950 to 1952 in the files http://tools.ietf.org/html/rfc1950 27 (zlib format), rfc1951 (deflate format) and rfc1952 (gzip format). 28 */ 29 30 #ifndef ZLIB_H 31 #define ZLIB_H 32 33 #include "zconf.h" 34 35 #ifdef __cplusplus 36 extern "C" { 37 #endif 38 39 #define ZLIB_VERSION "1.2.8" 40 #define ZLIB_VERNUM 0x1280 41 #define ZLIB_VER_MAJOR 1 42 #define ZLIB_VER_MINOR 2 43 #define ZLIB_VER_REVISION 8 44 #define ZLIB_VER_SUBREVISION 0 45 46 /* 47 The 'zlib' compression library provides in-memory compression and 48 decompression functions, including integrity checks of the uncompressed data. 49 This version of the library supports only one compression method (deflation) 50 but other algorithms will be added later and will have the same stream 51 interface. 52 53 Compression can be done in a single step if the buffers are large enough, 54 or can be done by repeated calls of the compression function. In the latter 55 case, the application must provide more input and/or consume the output 56 (providing more output space) before each call. 57 58 The compressed data format used by default by the in-memory functions is 59 the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped 60 around a deflate stream, which is itself documented in RFC 1951. 61 62 The library also supports reading and writing files in gzip (.gz) format 63 with an interface similar to that of stdio using the functions that start 64 with "gz". The gzip format is different from the zlib format. gzip is a 65 gzip wrapper, documented in RFC 1952, wrapped around a deflate stream. 66 67 This library can optionally read and write gzip streams in memory as well. 68 69 The zlib format was designed to be compact and fast for use in memory 70 and on communications channels. The gzip format was designed for single- 71 file compression on file systems, has a larger header than zlib to maintain 72 directory information, and uses a different, slower check method than zlib. 73 74 The library does not install any signal handler. The decoder checks 75 the consistency of the compressed data, so the library should never crash 76 even in case of corrupted input. 77 */ 78 79 typedef voidpf(*alloc_func) OF((voidpf opaque, uInt items, uInt size)); 80 typedef void (*free_func) OF((voidpf opaque, voidpf address)); 81 82 struct internal_state; 83 84 typedef struct z_stream_s { 85 z_const Bytef *next_in; /* next input byte */ 86 uInt avail_in; /* number of bytes available at next_in */ 87 uLong total_in; /* total number of input bytes read so far */ 88 89 Bytef *next_out; /* next output byte should be put there */ 90 uInt avail_out; /* remaining free space at next_out */ 91 uLong total_out; /* total number of bytes output so far */ 92 93 z_const char *msg; /* last error message, NULL if no error */ 94 struct internal_state FAR *state; /* not visible by applications */ 95 96 alloc_func zalloc; /* used to allocate the internal state */ 97 free_func zfree; /* used to free the internal state */ 98 voidpf opaque; /* private data object passed to zalloc and zfree */ 99 100 int data_type; /* best guess about the data type: binary or text */ 101 uLong adler; /* adler32 value of the uncompressed data */ 102 uLong reserved; /* reserved for future use */ 103 } z_stream; 104 105 typedef z_stream FAR *z_streamp; 106 107 /* 108 gzip header information passed to and from zlib routines. See RFC 1952 109 for more details on the meanings of these fields. 110 */ 111 typedef struct gz_header_s { 112 int text; /* true if compressed data believed to be text */ 113 uLong time; /* modification time */ 114 int xflags; /* extra flags (not used when writing a gzip file) */ 115 int os; /* operating system */ 116 Bytef *extra; /* pointer to extra field or Z_NULL if none */ 117 uInt extra_len; /* extra field length (valid if extra != Z_NULL) */ 118 uInt extra_max; /* space at extra (only when reading header) */ 119 Bytef *name; /* pointer to zero-terminated file name or Z_NULL */ 120 uInt name_max; /* space at name (only when reading header) */ 121 Bytef *comment; /* pointer to zero-terminated comment or Z_NULL */ 122 uInt comm_max; /* space at comment (only when reading header) */ 123 int hcrc; /* true if there was or will be a header crc */ 124 int done; /* true when done reading gzip header (not used 125 when writing a gzip file) */ 126 } gz_header; 127 128 typedef gz_header FAR *gz_headerp; 129 130 /* 131 The application must update next_in and avail_in when avail_in has dropped 132 to zero. It must update next_out and avail_out when avail_out has dropped 133 to zero. The application must initialize zalloc, zfree and opaque before 134 calling the init function. All other fields are set by the compression 135 library and must not be updated by the application. 136 137 The opaque value provided by the application will be passed as the first 138 parameter for calls of zalloc and zfree. This can be useful for custom 139 memory management. The compression library attaches no meaning to the 140 opaque value. 141 142 zalloc must return Z_NULL if there is not enough memory for the object. 143 If zlib is used in a multi-threaded application, zalloc and zfree must be 144 thread safe. 145 146 On 16-bit systems, the functions zalloc and zfree must be able to allocate 147 exactly 65536 bytes, but will not be required to allocate more than this if 148 the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, pointers 149 returned by zalloc for objects of exactly 65536 bytes *must* have their 150 offset normalized to zero. The default allocation function provided by this 151 library ensures this (see zutil.c). To reduce memory requirements and avoid 152 any allocation of 64K objects, at the expense of compression ratio, compile 153 the library with -DMAX_WBITS=14 (see zconf.h). 154 155 The fields total_in and total_out can be used for statistics or progress 156 reports. After compression, total_in holds the total size of the 157 uncompressed data and may be saved for use in the decompressor (particularly 158 if the decompressor wants to decompress everything in a single step). 159 */ 160 161 /* constants */ 162 163 #define Z_NO_FLUSH 0 164 #define Z_PARTIAL_FLUSH 1 165 #define Z_SYNC_FLUSH 2 166 #define Z_FULL_FLUSH 3 167 #define Z_FINISH 4 168 #define Z_BLOCK 5 169 #define Z_TREES 6 170 /* Allowed flush values; see deflate() and inflate() below for details */ 171 172 #define Z_OK 0 173 #define Z_STREAM_END 1 174 #define Z_NEED_DICT 2 175 #define Z_ERRNO (-1) 176 #define Z_STREAM_ERROR (-2) 177 #define Z_DATA_ERROR (-3) 178 #define Z_MEM_ERROR (-4) 179 #define Z_BUF_ERROR (-5) 180 #define Z_VERSION_ERROR (-6) 181 /* Return codes for the compression/decompression functions. Negative values 182 * are errors, positive values are used for special but normal events. 183 */ 184 185 #define Z_NO_COMPRESSION 0 186 #define Z_BEST_SPEED 1 187 #define Z_BEST_COMPRESSION 9 188 #define Z_DEFAULT_COMPRESSION (-1) 189 /* compression levels */ 190 191 #define Z_FILTERED 1 192 #define Z_HUFFMAN_ONLY 2 193 #define Z_RLE 3 194 #define Z_FIXED 4 195 #define Z_DEFAULT_STRATEGY 0 196 /* compression strategy; see deflateInit2() below for details */ 197 198 #define Z_BINARY 0 199 #define Z_TEXT 1 200 #define Z_ASCII Z_TEXT /* for compatibility with 1.2.2 and earlier */ 201 #define Z_UNKNOWN 2 202 /* Possible values of the data_type field (though see inflate()) */ 203 204 #define Z_DEFLATED 8 205 /* The deflate compression method (the only one supported in this version) */ 206 207 #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */ 208 209 #define zlib_version zlibVersion() 210 /* for compatibility with versions < 1.0.2 */ 211 212 /* basic functions */ 213 214 ZEXTERN const char *ZEXPORT zlibVersion OF((void)); 215 /* The application can compare zlibVersion and ZLIB_VERSION for consistency. 216 If the first character differs, the library code actually used is not 217 compatible with the zlib.h header file used by the application. This check 218 is automatically made by deflateInit and inflateInit. 219 */ 220 221 /* 222 ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level)); 223 224 Initializes the internal stream state for compression. The fields 225 zalloc, zfree and opaque must be initialized before by the caller. If 226 zalloc and zfree are set to Z_NULL, deflateInit updates them to use default 227 allocation functions. 228 229 The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9: 230 1 gives best speed, 9 gives best compression, 0 gives no compression at all 231 (the input data is simply copied a block at a time). Z_DEFAULT_COMPRESSION 232 requests a default compromise between speed and compression (currently 233 equivalent to level 6). 234 235 deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough 236 memory, Z_STREAM_ERROR if level is not a valid compression level, or 237 Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible 238 with the version assumed by the caller (ZLIB_VERSION). msg is set to null 239 if there is no error message. deflateInit does not perform any compression: 240 this will be done by deflate(). 241 */ 242 243 ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush)); 244 /* 245 deflate compresses as much data as possible, and stops when the input 246 buffer becomes empty or the output buffer becomes full. It may introduce 247 some output latency (reading input without producing any output) except when 248 forced to flush. 249 250 The detailed semantics are as follows. deflate performs one or both of the 251 following actions: 252 253 - Compress more input starting at next_in and update next_in and avail_in 254 accordingly. If not all input can be processed (because there is not 255 enough room in the output buffer), next_in and avail_in are updated and 256 processing will resume at this point for the next call of deflate(). 257 258 - Provide more output starting at next_out and update next_out and avail_out 259 accordingly. This action is forced if the parameter flush is non zero. 260 Forcing flush frequently degrades the compression ratio, so this parameter 261 should be set only when necessary (in interactive applications). Some 262 output may be provided even if flush is not set. 263 264 Before the call of deflate(), the application should ensure that at least 265 one of the actions is possible, by providing more input and/or consuming more 266 output, and updating avail_in or avail_out accordingly; avail_out should 267 never be zero before the call. The application can consume the compressed 268 output when it wants, for example when the output buffer is full (avail_out 269 == 0), or after each call of deflate(). If deflate returns Z_OK and with 270 zero avail_out, it must be called again after making room in the output 271 buffer because there might be more output pending. 272 273 Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to 274 decide how much data to accumulate before producing output, in order to 275 maximize compression. 276 277 If the parameter flush is set to Z_SYNC_FLUSH, all pending output is 278 flushed to the output buffer and the output is aligned on a byte boundary, so 279 that the decompressor can get all input data available so far. (In 280 particular avail_in is zero after the call if enough output space has been 281 provided before the call.) Flushing may degrade compression for some 282 compression algorithms and so it should be used only when necessary. This 283 completes the current deflate block and follows it with an empty stored block 284 that is three bits plus filler bits to the next byte, followed by four bytes 285 (00 00 ff ff). 286 287 If flush is set to Z_PARTIAL_FLUSH, all pending output is flushed to the 288 output buffer, but the output is not aligned to a byte boundary. All of the 289 input data so far will be available to the decompressor, as for Z_SYNC_FLUSH. 290 This completes the current deflate block and follows it with an empty fixed 291 codes block that is 10 bits long. This assures that enough bytes are output 292 in order for the decompressor to finish the block before the empty fixed code 293 block. 294 295 If flush is set to Z_BLOCK, a deflate block is completed and emitted, as 296 for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to 297 seven bits of the current block are held to be written as the next byte after 298 the next deflate block is completed. In this case, the decompressor may not 299 be provided enough bits at this point in order to complete decompression of 300 the data provided so far to the compressor. It may need to wait for the next 301 block to be emitted. This is for advanced applications that need to control 302 the emission of deflate blocks. 303 304 If flush is set to Z_FULL_FLUSH, all output is flushed as with 305 Z_SYNC_FLUSH, and the compression state is reset so that decompression can 306 restart from this point if previous compressed data has been damaged or if 307 random access is desired. Using Z_FULL_FLUSH too often can seriously degrade 308 compression. 309 310 If deflate returns with avail_out == 0, this function must be called again 311 with the same value of the flush parameter and more output space (updated 312 avail_out), until the flush is complete (deflate returns with non-zero 313 avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that 314 avail_out is greater than six to avoid repeated flush markers due to 315 avail_out == 0 on return. 316 317 If the parameter flush is set to Z_FINISH, pending input is processed, 318 pending output is flushed and deflate returns with Z_STREAM_END if there was 319 enough output space; if deflate returns with Z_OK, this function must be 320 called again with Z_FINISH and more output space (updated avail_out) but no 321 more input data, until it returns with Z_STREAM_END or an error. After 322 deflate has returned Z_STREAM_END, the only possible operations on the stream 323 are deflateReset or deflateEnd. 324 325 Z_FINISH can be used immediately after deflateInit if all the compression 326 is to be done in a single step. In this case, avail_out must be at least the 327 value returned by deflateBound (see below). Then deflate is guaranteed to 328 return Z_STREAM_END. If not enough output space is provided, deflate will 329 not return Z_STREAM_END, and it must be called again as described above. 330 331 deflate() sets strm->adler to the adler32 checksum of all input read 332 so far (that is, total_in bytes). 333 334 deflate() may update strm->data_type if it can make a good guess about 335 the input data type (Z_BINARY or Z_TEXT). In doubt, the data is considered 336 binary. This field is only for information purposes and does not affect the 337 compression algorithm in any manner. 338 339 deflate() returns Z_OK if some progress has been made (more input 340 processed or more output produced), Z_STREAM_END if all input has been 341 consumed and all output has been produced (only when flush is set to 342 Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example 343 if next_in or next_out was Z_NULL), Z_BUF_ERROR if no progress is possible 344 (for example avail_in or avail_out was zero). Note that Z_BUF_ERROR is not 345 fatal, and deflate() can be called again with more input and more output 346 space to continue compressing. 347 */ 348 349 ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm)); 350 /* 351 All dynamically allocated data structures for this stream are freed. 352 This function discards any unprocessed input and does not flush any pending 353 output. 354 355 deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the 356 stream state was inconsistent, Z_DATA_ERROR if the stream was freed 357 prematurely (some input or output was discarded). In the error case, msg 358 may be set but then points to a static string (which must not be 359 deallocated). 360 */ 361 362 /* 363 ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm)); 364 365 Initializes the internal stream state for decompression. The fields 366 next_in, avail_in, zalloc, zfree and opaque must be initialized before by 367 the caller. If next_in is not Z_NULL and avail_in is large enough (the 368 exact value depends on the compression method), inflateInit determines the 369 compression method from the zlib header and allocates all data structures 370 accordingly; otherwise the allocation will be deferred to the first call of 371 inflate. If zalloc and zfree are set to Z_NULL, inflateInit updates them to 372 use default allocation functions. 373 374 inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough 375 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the 376 version assumed by the caller, or Z_STREAM_ERROR if the parameters are 377 invalid, such as a null pointer to the structure. msg is set to null if 378 there is no error message. inflateInit does not perform any decompression 379 apart from possibly reading the zlib header if present: actual decompression 380 will be done by inflate(). (So next_in and avail_in may be modified, but 381 next_out and avail_out are unused and unchanged.) The current implementation 382 of inflateInit() does not process any header information -- that is deferred 383 until inflate() is called. 384 */ 385 386 ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush)); 387 /* 388 inflate decompresses as much data as possible, and stops when the input 389 buffer becomes empty or the output buffer becomes full. It may introduce 390 some output latency (reading input without producing any output) except when 391 forced to flush. 392 393 The detailed semantics are as follows. inflate performs one or both of the 394 following actions: 395 396 - Decompress more input starting at next_in and update next_in and avail_in 397 accordingly. If not all input can be processed (because there is not 398 enough room in the output buffer), next_in is updated and processing will 399 resume at this point for the next call of inflate(). 400 401 - Provide more output starting at next_out and update next_out and avail_out 402 accordingly. inflate() provides as much output as possible, until there is 403 no more input data or no more space in the output buffer (see below about 404 the flush parameter). 405 406 Before the call of inflate(), the application should ensure that at least 407 one of the actions is possible, by providing more input and/or consuming more 408 output, and updating the next_* and avail_* values accordingly. The 409 application can consume the uncompressed output when it wants, for example 410 when the output buffer is full (avail_out == 0), or after each call of 411 inflate(). If inflate returns Z_OK and with zero avail_out, it must be 412 called again after making room in the output buffer because there might be 413 more output pending. 414 415 The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, Z_FINISH, 416 Z_BLOCK, or Z_TREES. Z_SYNC_FLUSH requests that inflate() flush as much 417 output as possible to the output buffer. Z_BLOCK requests that inflate() 418 stop if and when it gets to the next deflate block boundary. When decoding 419 the zlib or gzip format, this will cause inflate() to return immediately 420 after the header and before the first block. When doing a raw inflate, 421 inflate() will go ahead and process the first block, and will return when it 422 gets to the end of that block, or when it runs out of data. 423 424 The Z_BLOCK option assists in appending to or combining deflate streams. 425 Also to assist in this, on return inflate() will set strm->data_type to the 426 number of unused bits in the last byte taken from strm->next_in, plus 64 if 427 inflate() is currently decoding the last block in the deflate stream, plus 428 128 if inflate() returned immediately after decoding an end-of-block code or 429 decoding the complete header up to just before the first byte of the deflate 430 stream. The end-of-block will not be indicated until all of the uncompressed 431 data from that block has been written to strm->next_out. The number of 432 unused bits may in general be greater than seven, except when bit 7 of 433 data_type is set, in which case the number of unused bits will be less than 434 eight. data_type is set as noted here every time inflate() returns for all 435 flush options, and so can be used to determine the amount of currently 436 consumed input in bits. 437 438 The Z_TREES option behaves as Z_BLOCK does, but it also returns when the 439 end of each deflate block header is reached, before any actual data in that 440 block is decoded. This allows the caller to determine the length of the 441 deflate block header for later use in random access within a deflate block. 442 256 is added to the value of strm->data_type when inflate() returns 443 immediately after reaching the end of the deflate block header. 444 445 inflate() should normally be called until it returns Z_STREAM_END or an 446 error. However if all decompression is to be performed in a single step (a 447 single call of inflate), the parameter flush should be set to Z_FINISH. In 448 this case all pending input is processed and all pending output is flushed; 449 avail_out must be large enough to hold all of the uncompressed data for the 450 operation to complete. (The size of the uncompressed data may have been 451 saved by the compressor for this purpose.) The use of Z_FINISH is not 452 required to perform an inflation in one step. However it may be used to 453 inform inflate that a faster approach can be used for the single inflate() 454 call. Z_FINISH also informs inflate to not maintain a sliding window if the 455 stream completes, which reduces inflate's memory footprint. If the stream 456 does not complete, either because not all of the stream is provided or not 457 enough output space is provided, then a sliding window will be allocated and 458 inflate() can be called again to continue the operation as if Z_NO_FLUSH had 459 been used. 460 461 In this implementation, inflate() always flushes as much output as 462 possible to the output buffer, and always uses the faster approach on the 463 first call. So the effects of the flush parameter in this implementation are 464 on the return value of inflate() as noted below, when inflate() returns early 465 when Z_BLOCK or Z_TREES is used, and when inflate() avoids the allocation of 466 memory for a sliding window when Z_FINISH is used. 467 468 If a preset dictionary is needed after this call (see inflateSetDictionary 469 below), inflate sets strm->adler to the Adler-32 checksum of the dictionary 470 chosen by the compressor and returns Z_NEED_DICT; otherwise it sets 471 strm->adler to the Adler-32 checksum of all output produced so far (that is, 472 total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described 473 below. At the end of the stream, inflate() checks that its computed adler32 474 checksum is equal to that saved by the compressor and returns Z_STREAM_END 475 only if the checksum is correct. 476 477 inflate() can decompress and check either zlib-wrapped or gzip-wrapped 478 deflate data. The header type is detected automatically, if requested when 479 initializing with inflateInit2(). Any information contained in the gzip 480 header is not retained, so applications that need that information should 481 instead use raw inflate, see inflateInit2() below, or inflateBack() and 482 perform their own processing of the gzip header and trailer. When processing 483 gzip-wrapped deflate data, strm->adler32 is set to the CRC-32 of the output 484 producted so far. The CRC-32 is checked against the gzip trailer. 485 486 inflate() returns Z_OK if some progress has been made (more input processed 487 or more output produced), Z_STREAM_END if the end of the compressed data has 488 been reached and all uncompressed output has been produced, Z_NEED_DICT if a 489 preset dictionary is needed at this point, Z_DATA_ERROR if the input data was 490 corrupted (input stream not conforming to the zlib format or incorrect check 491 value), Z_STREAM_ERROR if the stream structure was inconsistent (for example 492 next_in or next_out was Z_NULL), Z_MEM_ERROR if there was not enough memory, 493 Z_BUF_ERROR if no progress is possible or if there was not enough room in the 494 output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and 495 inflate() can be called again with more input and more output space to 496 continue decompressing. If Z_DATA_ERROR is returned, the application may 497 then call inflateSync() to look for a good compression block if a partial 498 recovery of the data is desired. 499 */ 500 501 ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm)); 502 /* 503 All dynamically allocated data structures for this stream are freed. 504 This function discards any unprocessed input and does not flush any pending 505 output. 506 507 inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state 508 was inconsistent. In the error case, msg may be set but then points to a 509 static string (which must not be deallocated). 510 */ 511 512 /* Advanced functions */ 513 514 /* 515 The following functions are needed only in some special applications. 516 */ 517 518 /* 519 ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm, 520 int level, 521 int method, 522 int windowBits, 523 int memLevel, 524 int strategy)); 525 526 This is another version of deflateInit with more compression options. The 527 fields next_in, zalloc, zfree and opaque must be initialized before by the 528 caller. 529 530 The method parameter is the compression method. It must be Z_DEFLATED in 531 this version of the library. 532 533 The windowBits parameter is the base two logarithm of the window size 534 (the size of the history buffer). It should be in the range 8..15 for this 535 version of the library. Larger values of this parameter result in better 536 compression at the expense of memory usage. The default value is 15 if 537 deflateInit is used instead. 538 539 windowBits can also be -8..-15 for raw deflate. In this case, -windowBits 540 determines the window size. deflate() will then generate raw deflate data 541 with no zlib header or trailer, and will not compute an adler32 check value. 542 543 windowBits can also be greater than 15 for optional gzip encoding. Add 544 16 to windowBits to write a simple gzip header and trailer around the 545 compressed data instead of a zlib wrapper. The gzip header will have no 546 file name, no extra data, no comment, no modification time (set to zero), no 547 header crc, and the operating system will be set to 255 (unknown). If a 548 gzip stream is being written, strm->adler is a crc32 instead of an adler32. 549 550 The memLevel parameter specifies how much memory should be allocated 551 for the internal compression state. memLevel=1 uses minimum memory but is 552 slow and reduces compression ratio; memLevel=9 uses maximum memory for 553 optimal speed. The default value is 8. See zconf.h for total memory usage 554 as a function of windowBits and memLevel. 555 556 The strategy parameter is used to tune the compression algorithm. Use the 557 value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a 558 filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no 559 string match), or Z_RLE to limit match distances to one (run-length 560 encoding). Filtered data consists mostly of small values with a somewhat 561 random distribution. In this case, the compression algorithm is tuned to 562 compress them better. The effect of Z_FILTERED is to force more Huffman 563 coding and less string matching; it is somewhat intermediate between 564 Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as 565 fast as Z_HUFFMAN_ONLY, but give better compression for PNG image data. The 566 strategy parameter only affects the compression ratio but not the 567 correctness of the compressed output even if it is not set appropriately. 568 Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler 569 decoder for special applications. 570 571 deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 572 memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid 573 method), or Z_VERSION_ERROR if the zlib library version (zlib_version) is 574 incompatible with the version assumed by the caller (ZLIB_VERSION). msg is 575 set to null if there is no error message. deflateInit2 does not perform any 576 compression: this will be done by deflate(). 577 */ 578 579 ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm, const Bytef * dictionary, uInt dictLength)); 580 /* 581 Initializes the compression dictionary from the given byte sequence 582 without producing any compressed output. When using the zlib format, this 583 function must be called immediately after deflateInit, deflateInit2 or 584 deflateReset, and before any call of deflate. When doing raw deflate, this 585 function must be called either before any call of deflate, or immediately 586 after the completion of a deflate block, i.e. after all input has been 587 consumed and all output has been delivered when using any of the flush 588 options Z_BLOCK, Z_PARTIAL_FLUSH, Z_SYNC_FLUSH, or Z_FULL_FLUSH. The 589 compressor and decompressor must use exactly the same dictionary (see 590 inflateSetDictionary). 591 592 The dictionary should consist of strings (byte sequences) that are likely 593 to be encountered later in the data to be compressed, with the most commonly 594 used strings preferably put towards the end of the dictionary. Using a 595 dictionary is most useful when the data to be compressed is short and can be 596 predicted with good accuracy; the data can then be compressed better than 597 with the default empty dictionary. 598 599 Depending on the size of the compression data structures selected by 600 deflateInit or deflateInit2, a part of the dictionary may in effect be 601 discarded, for example if the dictionary is larger than the window size 602 provided in deflateInit or deflateInit2. Thus the strings most likely to be 603 useful should be put at the end of the dictionary, not at the front. In 604 addition, the current implementation of deflate will use at most the window 605 size minus 262 bytes of the provided dictionary. 606 607 Upon return of this function, strm->adler is set to the adler32 value 608 of the dictionary; the decompressor may later use this value to determine 609 which dictionary has been used by the compressor. (The adler32 value 610 applies to the whole dictionary even if only a subset of the dictionary is 611 actually used by the compressor.) If a raw deflate was requested, then the 612 adler32 value is not computed and strm->adler is not set. 613 614 deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a 615 parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is 616 inconsistent (for example if deflate has already been called for this stream 617 or if not at a block boundary for raw deflate). deflateSetDictionary does 618 not perform any compression: this will be done by deflate(). 619 */ 620 621 ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest, z_streamp source)); 622 /* 623 Sets the destination stream as a complete copy of the source stream. 624 625 This function can be useful when several compression strategies will be 626 tried, for example when there are several ways of pre-processing the input 627 data with a filter. The streams that will be discarded should then be freed 628 by calling deflateEnd. Note that deflateCopy duplicates the internal 629 compression state which can be quite large, so this strategy is slow and can 630 consume lots of memory. 631 632 deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not 633 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent 634 (such as zalloc being Z_NULL). msg is left unchanged in both source and 635 destination. 636 */ 637 638 ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm)); 639 /* 640 This function is equivalent to deflateEnd followed by deflateInit, 641 but does not free and reallocate all the internal compression state. The 642 stream will keep the same compression level and any other attributes that 643 may have been set by deflateInit2. 644 645 deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source 646 stream state was inconsistent (such as zalloc or state being Z_NULL). 647 */ 648 649 ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm, int level, int strategy)); 650 /* 651 Dynamically update the compression level and compression strategy. The 652 interpretation of level and strategy is as in deflateInit2. This can be 653 used to switch between compression and straight copy of the input data, or 654 to switch to a different kind of input data requiring a different strategy. 655 If the compression level is changed, the input available so far is 656 compressed with the old level (and may be flushed); the new level will take 657 effect only at the next call of deflate(). 658 659 Before the call of deflateParams, the stream state must be set as for 660 a call of deflate(), since the currently available input may have to be 661 compressed and flushed. In particular, strm->avail_out must be non-zero. 662 663 deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source 664 stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR if 665 strm->avail_out was zero. 666 */ 667 668 ZEXTERN int ZEXPORT deflateTune OF((z_streamp strm, int good_length, int max_lazy, int nice_length, int max_chain)); 669 /* 670 Fine tune deflate's internal compression parameters. This should only be 671 used by someone who understands the algorithm used by zlib's deflate for 672 searching for the best matching string, and even then only by the most 673 fanatic optimizer trying to squeeze out the last compressed bit for their 674 specific input data. Read the deflate.c source code for the meaning of the 675 max_lazy, good_length, nice_length, and max_chain parameters. 676 677 deflateTune() can be called after deflateInit() or deflateInit2(), and 678 returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream. 679 */ 680 681 ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm, uLong sourceLen)); 682 /* 683 deflateBound() returns an upper bound on the compressed size after 684 deflation of sourceLen bytes. It must be called after deflateInit() or 685 deflateInit2(), and after deflateSetHeader(), if used. This would be used 686 to allocate an output buffer for deflation in a single pass, and so would be 687 called before deflate(). If that first deflate() call is provided the 688 sourceLen input bytes, an output buffer allocated to the size returned by 689 deflateBound(), and the flush value Z_FINISH, then deflate() is guaranteed 690 to return Z_STREAM_END. Note that it is possible for the compressed size to 691 be larger than the value returned by deflateBound() if flush options other 692 than Z_FINISH or Z_NO_FLUSH are used. 693 */ 694 695 ZEXTERN int ZEXPORT deflatePending OF((z_streamp strm, unsigned *pending, int *bits)); 696 /* 697 deflatePending() returns the number of bytes and bits of output that have 698 been generated, but not yet provided in the available output. The bytes not 699 provided would be due to the available output space having being consumed. 700 The number of bits of output not provided are between 0 and 7, where they 701 await more bits to join them in order to fill out a full byte. If pending 702 or bits are Z_NULL, then those values are not set. 703 704 deflatePending returns Z_OK if success, or Z_STREAM_ERROR if the source 705 stream state was inconsistent. 706 */ 707 708 ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm, int bits, int value)); 709 /* 710 deflatePrime() inserts bits in the deflate output stream. The intent 711 is that this function is used to start off the deflate output with the bits 712 leftover from a previous deflate stream when appending to it. As such, this 713 function can only be used for raw deflate, and must be used before the first 714 deflate() call after a deflateInit2() or deflateReset(). bits must be less 715 than or equal to 16, and that many of the least significant bits of value 716 will be inserted in the output. 717 718 deflatePrime returns Z_OK if success, Z_BUF_ERROR if there was not enough 719 room in the internal buffer to insert the bits, or Z_STREAM_ERROR if the 720 source stream state was inconsistent. 721 */ 722 723 ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm, gz_headerp head)); 724 /* 725 deflateSetHeader() provides gzip header information for when a gzip 726 stream is requested by deflateInit2(). deflateSetHeader() may be called 727 after deflateInit2() or deflateReset() and before the first call of 728 deflate(). The text, time, os, extra field, name, and comment information 729 in the provided gz_header structure are written to the gzip header (xflag is 730 ignored -- the extra flags are set according to the compression level). The 731 caller must assure that, if not Z_NULL, name and comment are terminated with 732 a zero byte, and that if extra is not Z_NULL, that extra_len bytes are 733 available there. If hcrc is true, a gzip header crc is included. Note that 734 the current versions of the command-line version of gzip (up through version 735 1.3.x) do not support header crc's, and will report that it is a "multi-part 736 gzip file" and give up. 737 738 If deflateSetHeader is not used, the default gzip header has text false, 739 the time set to zero, and os set to 255, with no extra, name, or comment 740 fields. The gzip header is returned to the default state by deflateReset(). 741 742 deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source 743 stream state was inconsistent. 744 */ 745 746 /* 747 ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm, 748 int windowBits)); 749 750 This is another version of inflateInit with an extra parameter. The 751 fields next_in, avail_in, zalloc, zfree and opaque must be initialized 752 before by the caller. 753 754 The windowBits parameter is the base two logarithm of the maximum window 755 size (the size of the history buffer). It should be in the range 8..15 for 756 this version of the library. The default value is 15 if inflateInit is used 757 instead. windowBits must be greater than or equal to the windowBits value 758 provided to deflateInit2() while compressing, or it must be equal to 15 if 759 deflateInit2() was not used. If a compressed stream with a larger window 760 size is given as input, inflate() will return with the error code 761 Z_DATA_ERROR instead of trying to allocate a larger window. 762 763 windowBits can also be zero to request that inflate use the window size in 764 the zlib header of the compressed stream. 765 766 windowBits can also be -8..-15 for raw inflate. In this case, -windowBits 767 determines the window size. inflate() will then process raw deflate data, 768 not looking for a zlib or gzip header, not generating a check value, and not 769 looking for any check values for comparison at the end of the stream. This 770 is for use with other formats that use the deflate compressed data format 771 such as zip. Those formats provide their own check values. If a custom 772 format is developed using the raw deflate format for compressed data, it is 773 recommended that a check value such as an adler32 or a crc32 be applied to 774 the uncompressed data as is done in the zlib, gzip, and zip formats. For 775 most applications, the zlib format should be used as is. Note that comments 776 above on the use in deflateInit2() applies to the magnitude of windowBits. 777 778 windowBits can also be greater than 15 for optional gzip decoding. Add 779 32 to windowBits to enable zlib and gzip decoding with automatic header 780 detection, or add 16 to decode only the gzip format (the zlib format will 781 return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is a 782 crc32 instead of an adler32. 783 784 inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 785 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the 786 version assumed by the caller, or Z_STREAM_ERROR if the parameters are 787 invalid, such as a null pointer to the structure. msg is set to null if 788 there is no error message. inflateInit2 does not perform any decompression 789 apart from possibly reading the zlib header if present: actual decompression 790 will be done by inflate(). (So next_in and avail_in may be modified, but 791 next_out and avail_out are unused and unchanged.) The current implementation 792 of inflateInit2() does not process any header information -- that is 793 deferred until inflate() is called. 794 */ 795 796 ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm, const Bytef * dictionary, uInt dictLength)); 797 /* 798 Initializes the decompression dictionary from the given uncompressed byte 799 sequence. This function must be called immediately after a call of inflate, 800 if that call returned Z_NEED_DICT. The dictionary chosen by the compressor 801 can be determined from the adler32 value returned by that call of inflate. 802 The compressor and decompressor must use exactly the same dictionary (see 803 deflateSetDictionary). For raw inflate, this function can be called at any 804 time to set the dictionary. If the provided dictionary is smaller than the 805 window and there is already data in the window, then the provided dictionary 806 will amend what's there. The application must insure that the dictionary 807 that was used for compression is provided. 808 809 inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a 810 parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is 811 inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the 812 expected one (incorrect adler32 value). inflateSetDictionary does not 813 perform any decompression: this will be done by subsequent calls of 814 inflate(). 815 */ 816 817 ZEXTERN int ZEXPORT inflateGetDictionary OF((z_streamp strm, Bytef * dictionary, uInt * dictLength)); 818 /* 819 Returns the sliding dictionary being maintained by inflate. dictLength is 820 set to the number of bytes in the dictionary, and that many bytes are copied 821 to dictionary. dictionary must have enough space, where 32768 bytes is 822 always enough. If inflateGetDictionary() is called with dictionary equal to 823 Z_NULL, then only the dictionary length is returned, and nothing is copied. 824 Similary, if dictLength is Z_NULL, then it is not set. 825 826 inflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the 827 stream state is inconsistent. 828 */ 829 830 ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm)); 831 /* 832 Skips invalid compressed data until a possible full flush point (see above 833 for the description of deflate with Z_FULL_FLUSH) can be found, or until all 834 available input is skipped. No output is provided. 835 836 inflateSync searches for a 00 00 FF FF pattern in the compressed data. 837 All full flush points have this pattern, but not all occurrences of this 838 pattern are full flush points. 839 840 inflateSync returns Z_OK if a possible full flush point has been found, 841 Z_BUF_ERROR if no more input was provided, Z_DATA_ERROR if no flush point 842 has been found, or Z_STREAM_ERROR if the stream structure was inconsistent. 843 In the success case, the application may save the current current value of 844 total_in which indicates where valid compressed data was found. In the 845 error case, the application may repeatedly call inflateSync, providing more 846 input each time, until success or end of the input data. 847 */ 848 849 ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest, z_streamp source)); 850 /* 851 Sets the destination stream as a complete copy of the source stream. 852 853 This function can be useful when randomly accessing a large stream. The 854 first pass through the stream can periodically record the inflate state, 855 allowing restarting inflate at those points when randomly accessing the 856 stream. 857 858 inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not 859 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent 860 (such as zalloc being Z_NULL). msg is left unchanged in both source and 861 destination. 862 */ 863 864 ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm)); 865 /* 866 This function is equivalent to inflateEnd followed by inflateInit, 867 but does not free and reallocate all the internal decompression state. The 868 stream will keep attributes that may have been set by inflateInit2. 869 870 inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source 871 stream state was inconsistent (such as zalloc or state being Z_NULL). 872 */ 873 874 ZEXTERN int ZEXPORT inflateReset2 OF((z_streamp strm, int windowBits)); 875 /* 876 This function is the same as inflateReset, but it also permits changing 877 the wrap and window size requests. The windowBits parameter is interpreted 878 the same as it is for inflateInit2. 879 880 inflateReset2 returns Z_OK if success, or Z_STREAM_ERROR if the source 881 stream state was inconsistent (such as zalloc or state being Z_NULL), or if 882 the windowBits parameter is invalid. 883 */ 884 885 ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm, int bits, int value)); 886 /* 887 This function inserts bits in the inflate input stream. The intent is 888 that this function is used to start inflating at a bit position in the 889 middle of a byte. The provided bits will be used before any bytes are used 890 from next_in. This function should only be used with raw inflate, and 891 should be used before the first inflate() call after inflateInit2() or 892 inflateReset(). bits must be less than or equal to 16, and that many of the 893 least significant bits of value will be inserted in the input. 894 895 If bits is negative, then the input stream bit buffer is emptied. Then 896 inflatePrime() can be called again to put bits in the buffer. This is used 897 to clear out bits leftover after feeding inflate a block description prior 898 to feeding inflate codes. 899 900 inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source 901 stream state was inconsistent. 902 */ 903 904 ZEXTERN long ZEXPORT inflateMark OF((z_streamp strm)); 905 /* 906 This function returns two values, one in the lower 16 bits of the return 907 value, and the other in the remaining upper bits, obtained by shifting the 908 return value down 16 bits. If the upper value is -1 and the lower value is 909 zero, then inflate() is currently decoding information outside of a block. 910 If the upper value is -1 and the lower value is non-zero, then inflate is in 911 the middle of a stored block, with the lower value equaling the number of 912 bytes from the input remaining to copy. If the upper value is not -1, then 913 it is the number of bits back from the current bit position in the input of 914 the code (literal or length/distance pair) currently being processed. In 915 that case the lower value is the number of bytes already emitted for that 916 code. 917 918 A code is being processed if inflate is waiting for more input to complete 919 decoding of the code, or if it has completed decoding but is waiting for 920 more output space to write the literal or match data. 921 922 inflateMark() is used to mark locations in the input data for random 923 access, which may be at bit positions, and to note those cases where the 924 output of a code may span boundaries of random access blocks. The current 925 location in the input stream can be determined from avail_in and data_type 926 as noted in the description for the Z_BLOCK flush parameter for inflate. 927 928 inflateMark returns the value noted above or -1 << 16 if the provided 929 source stream state was inconsistent. 930 */ 931 932 ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm, gz_headerp head)); 933 /* 934 inflateGetHeader() requests that gzip header information be stored in the 935 provided gz_header structure. inflateGetHeader() may be called after 936 inflateInit2() or inflateReset(), and before the first call of inflate(). 937 As inflate() processes the gzip stream, head->done is zero until the header 938 is completed, at which time head->done is set to one. If a zlib stream is 939 being decoded, then head->done is set to -1 to indicate that there will be 940 no gzip header information forthcoming. Note that Z_BLOCK or Z_TREES can be 941 used to force inflate() to return immediately after header processing is 942 complete and before any actual data is decompressed. 943 944 The text, time, xflags, and os fields are filled in with the gzip header 945 contents. hcrc is set to true if there is a header CRC. (The header CRC 946 was valid if done is set to one.) If extra is not Z_NULL, then extra_max 947 contains the maximum number of bytes to write to extra. Once done is true, 948 extra_len contains the actual extra field length, and extra contains the 949 extra field, or that field truncated if extra_max is less than extra_len. 950 If name is not Z_NULL, then up to name_max characters are written there, 951 terminated with a zero unless the length is greater than name_max. If 952 comment is not Z_NULL, then up to comm_max characters are written there, 953 terminated with a zero unless the length is greater than comm_max. When any 954 of extra, name, or comment are not Z_NULL and the respective field is not 955 present in the header, then that field is set to Z_NULL to signal its 956 absence. This allows the use of deflateSetHeader() with the returned 957 structure to duplicate the header. However if those fields are set to 958 allocated memory, then the application will need to save those pointers 959 elsewhere so that they can be eventually freed. 960 961 If inflateGetHeader is not used, then the header information is simply 962 discarded. The header is always checked for validity, including the header 963 CRC if present. inflateReset() will reset the process to discard the header 964 information. The application would need to call inflateGetHeader() again to 965 retrieve the header from the next gzip stream. 966 967 inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source 968 stream state was inconsistent. 969 */ 970 971 /* 972 ZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits, 973 unsigned char FAR *window)); 974 975 Initialize the internal stream state for decompression using inflateBack() 976 calls. The fields zalloc, zfree and opaque in strm must be initialized 977 before the call. If zalloc and zfree are Z_NULL, then the default library- 978 derived memory allocation routines are used. windowBits is the base two 979 logarithm of the window size, in the range 8..15. window is a caller 980 supplied buffer of that size. Except for special applications where it is 981 assured that deflate was used with small window sizes, windowBits must be 15 982 and a 32K byte window must be supplied to be able to decompress general 983 deflate streams. 984 985 See inflateBack() for the usage of these routines. 986 987 inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of 988 the parameters are invalid, Z_MEM_ERROR if the internal state could not be 989 allocated, or Z_VERSION_ERROR if the version of the library does not match 990 the version of the header file. 991 */ 992 993 typedef unsigned (*in_func) OF((void FAR *, z_const unsigned char FAR * FAR *)); 994 typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned)); 995 996 ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm, in_func in, void FAR * in_desc, out_func out, void FAR * out_desc)); 997 /* 998 inflateBack() does a raw inflate with a single call using a call-back 999 interface for input and output. This is potentially more efficient than 1000 inflate() for file i/o applications, in that it avoids copying between the 1001 output and the sliding window by simply making the window itself the output 1002 buffer. inflate() can be faster on modern CPUs when used with large 1003 buffers. inflateBack() trusts the application to not change the output 1004 buffer passed by the output function, at least until inflateBack() returns. 1005 1006 inflateBackInit() must be called first to allocate the internal state 1007 and to initialize the state with the user-provided window buffer. 1008 inflateBack() may then be used multiple times to inflate a complete, raw 1009 deflate stream with each call. inflateBackEnd() is then called to free the 1010 allocated state. 1011 1012 A raw deflate stream is one with no zlib or gzip header or trailer. 1013 This routine would normally be used in a utility that reads zip or gzip 1014 files and writes out uncompressed files. The utility would decode the 1015 header and process the trailer on its own, hence this routine expects only 1016 the raw deflate stream to decompress. This is different from the normal 1017 behavior of inflate(), which expects either a zlib or gzip header and 1018 trailer around the deflate stream. 1019 1020 inflateBack() uses two subroutines supplied by the caller that are then 1021 called by inflateBack() for input and output. inflateBack() calls those 1022 routines until it reads a complete deflate stream and writes out all of the 1023 uncompressed data, or until it encounters an error. The function's 1024 parameters and return types are defined above in the in_func and out_func 1025 typedefs. inflateBack() will call in(in_desc, &buf) which should return the 1026 number of bytes of provided input, and a pointer to that input in buf. If 1027 there is no input available, in() must return zero--buf is ignored in that 1028 case--and inflateBack() will return a buffer error. inflateBack() will call 1029 out(out_desc, buf, len) to write the uncompressed data buf[0..len-1]. out() 1030 should return zero on success, or non-zero on failure. If out() returns 1031 non-zero, inflateBack() will return with an error. Neither in() nor out() 1032 are permitted to change the contents of the window provided to 1033 inflateBackInit(), which is also the buffer that out() uses to write from. 1034 The length written by out() will be at most the window size. Any non-zero 1035 amount of input may be provided by in(). 1036 1037 For convenience, inflateBack() can be provided input on the first call by 1038 setting strm->next_in and strm->avail_in. If that input is exhausted, then 1039 in() will be called. Therefore strm->next_in must be initialized before 1040 calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called 1041 immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in 1042 must also be initialized, and then if strm->avail_in is not zero, input will 1043 initially be taken from strm->next_in[0 .. strm->avail_in - 1]. 1044 1045 The in_desc and out_desc parameters of inflateBack() is passed as the 1046 first parameter of in() and out() respectively when they are called. These 1047 descriptors can be optionally used to pass any information that the caller- 1048 supplied in() and out() functions need to do their job. 1049 1050 On return, inflateBack() will set strm->next_in and strm->avail_in to 1051 pass back any unused input that was provided by the last in() call. The 1052 return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR 1053 if in() or out() returned an error, Z_DATA_ERROR if there was a format error 1054 in the deflate stream (in which case strm->msg is set to indicate the nature 1055 of the error), or Z_STREAM_ERROR if the stream was not properly initialized. 1056 In the case of Z_BUF_ERROR, an input or output error can be distinguished 1057 using strm->next_in which will be Z_NULL only if in() returned an error. If 1058 strm->next_in is not Z_NULL, then the Z_BUF_ERROR was due to out() returning 1059 non-zero. (in() will always be called before out(), so strm->next_in is 1060 assured to be defined if out() returns non-zero.) Note that inflateBack() 1061 cannot return Z_OK. 1062 */ 1063 1064 ZEXTERN int ZEXPORT inflateBackEnd OF((z_streamp strm)); 1065 /* 1066 All memory allocated by inflateBackInit() is freed. 1067 1068 inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream 1069 state was inconsistent. 1070 */ 1071 1072 ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void)); 1073 /* Return flags indicating compile-time options. 1074 1075 Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other: 1076 1.0: size of uInt 1077 3.2: size of uLong 1078 5.4: size of voidpf (pointer) 1079 7.6: size of z_off_t 1080 1081 Compiler, assembler, and debug options: 1082 8: DEBUG 1083 9: ASMV or ASMINF -- use ASM code 1084 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention 1085 11: 0 (reserved) 1086 1087 One-time table building (smaller code, but not thread-safe if true): 1088 12: BUILDFIXED -- build static block decoding tables when needed 1089 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed 1090 14,15: 0 (reserved) 1091 1092 Library content (indicates missing functionality): 1093 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking 1094 deflate code when not needed) 1095 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect 1096 and decode gzip streams (to avoid linking crc code) 1097 18-19: 0 (reserved) 1098 1099 Operation variations (changes in library functionality): 1100 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate 1101 21: FASTEST -- deflate algorithm with only one, lowest compression level 1102 22,23: 0 (reserved) 1103 1104 The sprintf variant used by gzprintf (zero is best): 1105 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format 1106 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure! 1107 26: 0 = returns value, 1 = void -- 1 means inferred string length returned 1108 1109 Remainder: 1110 27-31: 0 (reserved) 1111 */ 1112 1113 #ifndef Z_SOLO 1114 1115 /* utility functions */ 1116 1117 /* 1118 The following utility functions are implemented on top of the basic 1119 stream-oriented functions. To simplify the interface, some default options 1120 are assumed (compression level and memory usage, standard memory allocation 1121 functions). The source code of these utility functions can be modified if 1122 you need special options. 1123 */ 1124 1125 ZEXTERN int ZEXPORT compress OF((Bytef * dest, uLongf * destLen, const Bytef * source, uLong sourceLen)); 1126 /* 1127 Compresses the source buffer into the destination buffer. sourceLen is 1128 the byte length of the source buffer. Upon entry, destLen is the total size 1129 of the destination buffer, which must be at least the value returned by 1130 compressBound(sourceLen). Upon exit, destLen is the actual size of the 1131 compressed buffer. 1132 1133 compress returns Z_OK if success, Z_MEM_ERROR if there was not 1134 enough memory, Z_BUF_ERROR if there was not enough room in the output 1135 buffer. 1136 */ 1137 1138 ZEXTERN int ZEXPORT compress2 OF((Bytef * dest, uLongf * destLen, const Bytef * source, uLong sourceLen, int level)); 1139 /* 1140 Compresses the source buffer into the destination buffer. The level 1141 parameter has the same meaning as in deflateInit. sourceLen is the byte 1142 length of the source buffer. Upon entry, destLen is the total size of the 1143 destination buffer, which must be at least the value returned by 1144 compressBound(sourceLen). Upon exit, destLen is the actual size of the 1145 compressed buffer. 1146 1147 compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 1148 memory, Z_BUF_ERROR if there was not enough room in the output buffer, 1149 Z_STREAM_ERROR if the level parameter is invalid. 1150 */ 1151 1152 ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen)); 1153 /* 1154 compressBound() returns an upper bound on the compressed size after 1155 compress() or compress2() on sourceLen bytes. It would be used before a 1156 compress() or compress2() call to allocate the destination buffer. 1157 */ 1158 1159 ZEXTERN int ZEXPORT uncompress OF((Bytef * dest, uLongf * destLen, const Bytef * source, uLong sourceLen)); 1160 /* 1161 Decompresses the source buffer into the destination buffer. sourceLen is 1162 the byte length of the source buffer. Upon entry, destLen is the total size 1163 of the destination buffer, which must be large enough to hold the entire 1164 uncompressed data. (The size of the uncompressed data must have been saved 1165 previously by the compressor and transmitted to the decompressor by some 1166 mechanism outside the scope of this compression library.) Upon exit, destLen 1167 is the actual size of the uncompressed buffer. 1168 1169 uncompress returns Z_OK if success, Z_MEM_ERROR if there was not 1170 enough memory, Z_BUF_ERROR if there was not enough room in the output 1171 buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete. In 1172 the case where there is not enough room, uncompress() will fill the output 1173 buffer with the uncompressed data up to that point. 1174 */ 1175 1176 /* gzip file access functions */ 1177 1178 /* 1179 This library supports reading and writing files in gzip (.gz) format with 1180 an interface similar to that of stdio, using the functions that start with 1181 "gz". The gzip format is different from the zlib format. gzip is a gzip 1182 wrapper, documented in RFC 1952, wrapped around a deflate stream. 1183 */ 1184 1185 typedef struct gzFile_s *gzFile; /* semi-opaque gzip file descriptor */ 1186 1187 /* 1188 ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode)); 1189 1190 Opens a gzip (.gz) file for reading or writing. The mode parameter is as 1191 in fopen ("rb" or "wb") but can also include a compression level ("wb9") or 1192 a strategy: 'f' for filtered data as in "wb6f", 'h' for Huffman-only 1193 compression as in "wb1h", 'R' for run-length encoding as in "wb1R", or 'F' 1194 for fixed code compression as in "wb9F". (See the description of 1195 deflateInit2 for more information about the strategy parameter.) 'T' will 1196 request transparent writing or appending with no compression and not using 1197 the gzip format. 1198 1199 "a" can be used instead of "w" to request that the gzip stream that will 1200 be written be appended to the file. "+" will result in an error, since 1201 reading and writing to the same gzip file is not supported. The addition of 1202 "x" when writing will create the file exclusively, which fails if the file 1203 already exists. On systems that support it, the addition of "e" when 1204 reading or writing will set the flag to close the file on an execve() call. 1205 1206 These functions, as well as gzip, will read and decode a sequence of gzip 1207 streams in a file. The append function of gzopen() can be used to create 1208 such a file. (Also see gzflush() for another way to do this.) When 1209 appending, gzopen does not test whether the file begins with a gzip stream, 1210 nor does it look for the end of the gzip streams to begin appending. gzopen 1211 will simply append a gzip stream to the existing file. 1212 1213 gzopen can be used to read a file which is not in gzip format; in this 1214 case gzread will directly read from the file without decompression. When 1215 reading, this will be detected automatically by looking for the magic two- 1216 byte gzip header. 1217 1218 gzopen returns NULL if the file could not be opened, if there was 1219 insufficient memory to allocate the gzFile state, or if an invalid mode was 1220 specified (an 'r', 'w', or 'a' was not provided, or '+' was provided). 1221 errno can be checked to determine if the reason gzopen failed was that the 1222 file could not be opened. 1223 */ 1224 1225 ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode)); 1226 /* 1227 gzdopen associates a gzFile with the file descriptor fd. File descriptors 1228 are obtained from calls like open, dup, creat, pipe or fileno (if the file 1229 has been previously opened with fopen). The mode parameter is as in gzopen. 1230 1231 The next call of gzclose on the returned gzFile will also close the file 1232 descriptor fd, just like fclose(fdopen(fd, mode)) closes the file descriptor 1233 fd. If you want to keep fd open, use fd = dup(fd_keep); gz = gzdopen(fd, 1234 mode);. The duplicated descriptor should be saved to avoid a leak, since 1235 gzdopen does not close fd if it fails. If you are using fileno() to get the 1236 file descriptor from a FILE *, then you will have to use dup() to avoid 1237 double-close()ing the file descriptor. Both gzclose() and fclose() will 1238 close the associated file descriptor, so they need to have different file 1239 descriptors. 1240 1241 gzdopen returns NULL if there was insufficient memory to allocate the 1242 gzFile state, if an invalid mode was specified (an 'r', 'w', or 'a' was not 1243 provided, or '+' was provided), or if fd is -1. The file descriptor is not 1244 used until the next gz* read, write, seek, or close operation, so gzdopen 1245 will not detect if fd is invalid (unless fd is -1). 1246 */ 1247 1248 ZEXTERN int ZEXPORT gzbuffer OF((gzFile file, unsigned size)); 1249 /* 1250 Set the internal buffer size used by this library's functions. The 1251 default buffer size is 8192 bytes. This function must be called after 1252 gzopen() or gzdopen(), and before any other calls that read or write the 1253 file. The buffer memory allocation is always deferred to the first read or 1254 write. Two buffers are allocated, either both of the specified size when 1255 writing, or one of the specified size and the other twice that size when 1256 reading. A larger buffer size of, for example, 64K or 128K bytes will 1257 noticeably increase the speed of decompression (reading). 1258 1259 The new buffer size also affects the maximum length for gzprintf(). 1260 1261 gzbuffer() returns 0 on success, or -1 on failure, such as being called 1262 too late. 1263 */ 1264 1265 ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy)); 1266 /* 1267 Dynamically update the compression level or strategy. See the description 1268 of deflateInit2 for the meaning of these parameters. 1269 1270 gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not 1271 opened for writing. 1272 */ 1273 1274 ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len)); 1275 /* 1276 Reads the given number of uncompressed bytes from the compressed file. If 1277 the input file is not in gzip format, gzread copies the given number of 1278 bytes into the buffer directly from the file. 1279 1280 After reaching the end of a gzip stream in the input, gzread will continue 1281 to read, looking for another gzip stream. Any number of gzip streams may be 1282 concatenated in the input file, and will all be decompressed by gzread(). 1283 If something other than a gzip stream is encountered after a gzip stream, 1284 that remaining trailing garbage is ignored (and no error is returned). 1285 1286 gzread can be used to read a gzip file that is being concurrently written. 1287 Upon reaching the end of the input, gzread will return with the available 1288 data. If the error code returned by gzerror is Z_OK or Z_BUF_ERROR, then 1289 gzclearerr can be used to clear the end of file indicator in order to permit 1290 gzread to be tried again. Z_OK indicates that a gzip stream was completed 1291 on the last gzread. Z_BUF_ERROR indicates that the input file ended in the 1292 middle of a gzip stream. Note that gzread does not return -1 in the event 1293 of an incomplete gzip stream. This error is deferred until gzclose(), which 1294 will return Z_BUF_ERROR if the last gzread ended in the middle of a gzip 1295 stream. Alternatively, gzerror can be used before gzclose to detect this 1296 case. 1297 1298 gzread returns the number of uncompressed bytes actually read, less than 1299 len for end of file, or -1 for error. 1300 */ 1301 1302 ZEXTERN int ZEXPORT gzwrite OF((gzFile file, voidpc buf, unsigned len)); 1303 /* 1304 Writes the given number of uncompressed bytes into the compressed file. 1305 gzwrite returns the number of uncompressed bytes written or 0 in case of 1306 error. 1307 */ 1308 1309 ZEXTERN int ZEXPORTVA gzprintf Z_ARG((gzFile file, const char *format, ...)); 1310 /* 1311 Converts, formats, and writes the arguments to the compressed file under 1312 control of the format string, as in fprintf. gzprintf returns the number of 1313 uncompressed bytes actually written, or 0 in case of error. The number of 1314 uncompressed bytes written is limited to 8191, or one less than the buffer 1315 size given to gzbuffer(). The caller should assure that this limit is not 1316 exceeded. If it is exceeded, then gzprintf() will return an error (0) with 1317 nothing written. In this case, there may also be a buffer overflow with 1318 unpredictable consequences, which is possible only if zlib was compiled with 1319 the insecure functions sprintf() or vsprintf() because the secure snprintf() 1320 or vsnprintf() functions were not available. This can be determined using 1321 zlibCompileFlags(). 1322 */ 1323 1324 ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s)); 1325 /* 1326 Writes the given null-terminated string to the compressed file, excluding 1327 the terminating null character. 1328 1329 gzputs returns the number of characters written, or -1 in case of error. 1330 */ 1331 1332 ZEXTERN char *ZEXPORT gzgets OF((gzFile file, char *buf, int len)); 1333 /* 1334 Reads bytes from the compressed file until len-1 characters are read, or a 1335 newline character is read and transferred to buf, or an end-of-file 1336 condition is encountered. If any characters are read or if len == 1, the 1337 string is terminated with a null character. If no characters are read due 1338 to an end-of-file or len < 1, then the buffer is left untouched. 1339 1340 gzgets returns buf which is a null-terminated string, or it returns NULL 1341 for end-of-file or in case of error. If there was an error, the contents at 1342 buf are indeterminate. 1343 */ 1344 1345 ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c)); 1346 /* 1347 Writes c, converted to an unsigned char, into the compressed file. gzputc 1348 returns the value that was written, or -1 in case of error. 1349 */ 1350 1351 ZEXTERN int ZEXPORT gzgetc OF((gzFile file)); 1352 /* 1353 Reads one byte from the compressed file. gzgetc returns this byte or -1 1354 in case of end of file or error. This is implemented as a macro for speed. 1355 As such, it does not do all of the checking the other functions do. I.e. 1356 it does not check to see if file is NULL, nor whether the structure file 1357 points to has been clobbered or not. 1358 */ 1359 1360 ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file)); 1361 /* 1362 Push one character back onto the stream to be read as the first character 1363 on the next read. At least one character of push-back is allowed. 1364 gzungetc() returns the character pushed, or -1 on failure. gzungetc() will 1365 fail if c is -1, and may fail if a character has been pushed but not read 1366 yet. If gzungetc is used immediately after gzopen or gzdopen, at least the 1367 output buffer size of pushed characters is allowed. (See gzbuffer above.) 1368 The pushed character will be discarded if the stream is repositioned with 1369 gzseek() or gzrewind(). 1370 */ 1371 1372 ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush)); 1373 /* 1374 Flushes all pending output into the compressed file. The parameter flush 1375 is as in the deflate() function. The return value is the zlib error number 1376 (see function gzerror below). gzflush is only permitted when writing. 1377 1378 If the flush parameter is Z_FINISH, the remaining data is written and the 1379 gzip stream is completed in the output. If gzwrite() is called again, a new 1380 gzip stream will be started in the output. gzread() is able to read such 1381 concatented gzip streams. 1382 1383 gzflush should be called only when strictly necessary because it will 1384 degrade compression if called too often. 1385 */ 1386 1387 /* 1388 ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file, 1389 z_off_t offset, int whence)); 1390 1391 Sets the starting position for the next gzread or gzwrite on the given 1392 compressed file. The offset represents a number of bytes in the 1393 uncompressed data stream. The whence parameter is defined as in lseek(2); 1394 the value SEEK_END is not supported. 1395 1396 If the file is opened for reading, this function is emulated but can be 1397 extremely slow. If the file is opened for writing, only forward seeks are 1398 supported; gzseek then compresses a sequence of zeroes up to the new 1399 starting position. 1400 1401 gzseek returns the resulting offset location as measured in bytes from 1402 the beginning of the uncompressed stream, or -1 in case of error, in 1403 particular if the file is opened for writing and the new starting position 1404 would be before the current position. 1405 */ 1406 1407 ZEXTERN int ZEXPORT gzrewind OF((gzFile file)); 1408 /* 1409 Rewinds the given file. This function is supported only for reading. 1410 1411 gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET) 1412 */ 1413 1414 /* 1415 ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file)); 1416 1417 Returns the starting position for the next gzread or gzwrite on the given 1418 compressed file. This position represents a number of bytes in the 1419 uncompressed data stream, and is zero when starting, even if appending or 1420 reading a gzip stream from the middle of a file using gzdopen(). 1421 1422 gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR) 1423 */ 1424 1425 /* 1426 ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile file)); 1427 1428 Returns the current offset in the file being read or written. This offset 1429 includes the count of bytes that precede the gzip stream, for example when 1430 appending or when using gzdopen() for reading. When reading, the offset 1431 does not include as yet unused buffered input. This information can be used 1432 for a progress indicator. On error, gzoffset() returns -1. 1433 */ 1434 1435 ZEXTERN int ZEXPORT gzeof OF((gzFile file)); 1436 /* 1437 Returns true (1) if the end-of-file indicator has been set while reading, 1438 false (0) otherwise. Note that the end-of-file indicator is set only if the 1439 read tried to go past the end of the input, but came up short. Therefore, 1440 just like feof(), gzeof() may return false even if there is no more data to 1441 read, in the event that the last read request was for the exact number of 1442 bytes remaining in the input file. This will happen if the input file size 1443 is an exact multiple of the buffer size. 1444 1445 If gzeof() returns true, then the read functions will return no more data, 1446 unless the end-of-file indicator is reset by gzclearerr() and the input file 1447 has grown since the previous end of file was detected. 1448 */ 1449 1450 ZEXTERN int ZEXPORT gzdirect OF((gzFile file)); 1451 /* 1452 Returns true (1) if file is being copied directly while reading, or false 1453 (0) if file is a gzip stream being decompressed. 1454 1455 If the input file is empty, gzdirect() will return true, since the input 1456 does not contain a gzip stream. 1457 1458 If gzdirect() is used immediately after gzopen() or gzdopen() it will 1459 cause buffers to be allocated to allow reading the file to determine if it 1460 is a gzip file. Therefore if gzbuffer() is used, it should be called before 1461 gzdirect(). 1462 1463 When writing, gzdirect() returns true (1) if transparent writing was 1464 requested ("wT" for the gzopen() mode), or false (0) otherwise. (Note: 1465 gzdirect() is not needed when writing. Transparent writing must be 1466 explicitly requested, so the application already knows the answer. When 1467 linking statically, using gzdirect() will include all of the zlib code for 1468 gzip file reading and decompression, which may not be desired.) 1469 */ 1470 1471 ZEXTERN int ZEXPORT gzclose OF((gzFile file)); 1472 /* 1473 Flushes all pending output if necessary, closes the compressed file and 1474 deallocates the (de)compression state. Note that once file is closed, you 1475 cannot call gzerror with file, since its structures have been deallocated. 1476 gzclose must not be called more than once on the same file, just as free 1477 must not be called more than once on the same allocation. 1478 1479 gzclose will return Z_STREAM_ERROR if file is not valid, Z_ERRNO on a 1480 file operation error, Z_MEM_ERROR if out of memory, Z_BUF_ERROR if the 1481 last read ended in the middle of a gzip stream, or Z_OK on success. 1482 */ 1483 1484 ZEXTERN int ZEXPORT gzclose_r OF((gzFile file)); 1485 ZEXTERN int ZEXPORT gzclose_w OF((gzFile file)); 1486 /* 1487 Same as gzclose(), but gzclose_r() is only for use when reading, and 1488 gzclose_w() is only for use when writing or appending. The advantage to 1489 using these instead of gzclose() is that they avoid linking in zlib 1490 compression or decompression code that is not used when only reading or only 1491 writing respectively. If gzclose() is used, then both compression and 1492 decompression code will be included the application when linking to a static 1493 zlib library. 1494 */ 1495 1496 ZEXTERN const char *ZEXPORT gzerror OF((gzFile file, int *errnum)); 1497 /* 1498 Returns the error message for the last error which occurred on the given 1499 compressed file. errnum is set to zlib error number. If an error occurred 1500 in the file system and not in the compression library, errnum is set to 1501 Z_ERRNO and the application may consult errno to get the exact error code. 1502 1503 The application must not modify the returned string. Future calls to 1504 this function may invalidate the previously returned string. If file is 1505 closed, then the string previously returned by gzerror will no longer be 1506 available. 1507 1508 gzerror() should be used to distinguish errors from end-of-file for those 1509 functions above that do not distinguish those cases in their return values. 1510 */ 1511 1512 ZEXTERN void ZEXPORT gzclearerr OF((gzFile file)); 1513 /* 1514 Clears the error and end-of-file flags for file. This is analogous to the 1515 clearerr() function in stdio. This is useful for continuing to read a gzip 1516 file that is being written concurrently. 1517 */ 1518 1519 #endif /* !Z_SOLO */ 1520 1521 /* checksum functions */ 1522 1523 /* 1524 These functions are not related to compression but are exported 1525 anyway because they might be useful in applications using the compression 1526 library. 1527 */ 1528 1529 ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef * buf, uInt len)); 1530 /* 1531 Update a running Adler-32 checksum with the bytes buf[0..len-1] and 1532 return the updated checksum. If buf is Z_NULL, this function returns the 1533 required initial value for the checksum. 1534 1535 An Adler-32 checksum is almost as reliable as a CRC32 but can be computed 1536 much faster. 1537 1538 Usage example: 1539 1540 uLong adler = adler32(0L, Z_NULL, 0); 1541 1542 while (read_buffer(buffer, length) != EOF) { 1543 adler = adler32(adler, buffer, length); 1544 } 1545 if (adler != original_adler) error(); 1546 */ 1547 1548 /* 1549 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong adler1, uLong adler2, 1550 z_off_t len2)); 1551 1552 Combine two Adler-32 checksums into one. For two sequences of bytes, seq1 1553 and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for 1554 each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of 1555 seq1 and seq2 concatenated, requiring only adler1, adler2, and len2. Note 1556 that the z_off_t type (like off_t) is a signed integer. If len2 is 1557 negative, the result has no meaning or utility. 1558 */ 1559 1560 ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef * buf, uInt len)); 1561 /* 1562 Update a running CRC-32 with the bytes buf[0..len-1] and return the 1563 updated CRC-32. If buf is Z_NULL, this function returns the required 1564 initial value for the crc. Pre- and post-conditioning (one's complement) is 1565 performed within this function so it shouldn't be done by the application. 1566 1567 Usage example: 1568 1569 uLong crc = crc32(0L, Z_NULL, 0); 1570 1571 while (read_buffer(buffer, length) != EOF) { 1572 crc = crc32(crc, buffer, length); 1573 } 1574 if (crc != original_crc) error(); 1575 */ 1576 1577 /* 1578 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2)); 1579 1580 Combine two CRC-32 check values into one. For two sequences of bytes, 1581 seq1 and seq2 with lengths len1 and len2, CRC-32 check values were 1582 calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32 1583 check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and 1584 len2. 1585 */ 1586 1587 /* various hacks, don't look :) */ 1588 1589 /* deflateInit and inflateInit are macros to allow checking the zlib version 1590 * and the compiler's view of z_stream: 1591 */ 1592 ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level, const char *version, int stream_size)); 1593 ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm, const char *version, int stream_size)); 1594 ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method, int windowBits, int memLevel, int strategy, const char *version, int stream_size)); 1595 ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits, const char *version, int stream_size)); 1596 ZEXTERN int ZEXPORT inflateBackInit_ OF((z_streamp strm, int windowBits, unsigned char FAR * window, const char *version, int stream_size)); 1597 #define deflateInit(strm, level) \ 1598 deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream)) 1599 #define inflateInit(strm) \ 1600 inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream)) 1601 #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \ 1602 deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\ 1603 (strategy), ZLIB_VERSION, (int)sizeof(z_stream)) 1604 #define inflateInit2(strm, windowBits) \ 1605 inflateInit2_((strm), (windowBits), ZLIB_VERSION, \ 1606 (int)sizeof(z_stream)) 1607 #define inflateBackInit(strm, windowBits, window) \ 1608 inflateBackInit_((strm), (windowBits), (window), \ 1609 ZLIB_VERSION, (int)sizeof(z_stream)) 1610 1611 #ifndef Z_SOLO 1612 1613 /* gzgetc() macro and its supporting function and exposed data structure. Note 1614 * that the real internal state is much larger than the exposed structure. 1615 * This abbreviated structure exposes just enough for the gzgetc() macro. The 1616 * user should not mess with these exposed elements, since their names or 1617 * behavior could change in the future, perhaps even capriciously. They can 1618 * only be used by the gzgetc() macro. You have been warned. 1619 */ 1620 struct gzFile_s { 1621 unsigned have; 1622 unsigned char *next; 1623 z_off64_t pos; 1624 }; 1625 ZEXTERN int ZEXPORT gzgetc_ OF((gzFile file)); /* backward compatibility */ 1626 #ifdef Z_PREFIX_SET 1627 #undef z_gzgetc 1628 #define z_gzgetc(g) \ 1629 ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : gzgetc(g)) 1630 #else 1631 #define gzgetc(g) \ 1632 ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : gzgetc(g)) 1633 #endif 1634 1635 /* provide 64-bit offset functions if _LARGEFILE64_SOURCE defined, and/or 1636 * change the regular functions to 64 bits if _FILE_OFFSET_BITS is 64 (if 1637 * both are true, the application gets the *64 functions, and the regular 1638 * functions are changed to 64 bits) -- in case these are set on systems 1639 * without large file support, _LFS64_LARGEFILE must also be true 1640 */ 1641 #ifdef Z_LARGE64 1642 ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *)); 1643 ZEXTERN z_off64_t ZEXPORT gzseek64 OF((gzFile, z_off64_t, int)); 1644 ZEXTERN z_off64_t ZEXPORT gztell64 OF((gzFile)); 1645 ZEXTERN z_off64_t ZEXPORT gzoffset64 OF((gzFile)); 1646 ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off64_t)); 1647 ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off64_t)); 1648 #endif 1649 1650 #if !defined(ZLIB_INTERNAL) && defined(Z_WANT64) 1651 #ifdef Z_PREFIX_SET 1652 #define z_gzopen z_gzopen64 1653 #define z_gzseek z_gzseek64 1654 #define z_gztell z_gztell64 1655 #define z_gzoffset z_gzoffset64 1656 #define z_adler32_combine z_adler32_combine64 1657 #define z_crc32_combine z_crc32_combine64 1658 #else 1659 #define gzopen gzopen64 1660 #define gzseek gzseek64 1661 #define gztell gztell64 1662 #define gzoffset gzoffset64 1663 #define adler32_combine adler32_combine64 1664 #define crc32_combine crc32_combine64 1665 #endif 1666 #ifndef Z_LARGE64 1667 ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *)); 1668 ZEXTERN z_off_t ZEXPORT gzseek64 OF((gzFile, z_off_t, int)); 1669 ZEXTERN z_off_t ZEXPORT gztell64 OF((gzFile)); 1670 ZEXTERN z_off_t ZEXPORT gzoffset64 OF((gzFile)); 1671 ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off_t)); 1672 ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off_t)); 1673 #endif 1674 #else 1675 ZEXTERN gzFile ZEXPORT gzopen OF((const char *, const char *)); 1676 ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile, z_off_t, int)); 1677 ZEXTERN z_off_t ZEXPORT gztell OF((gzFile)); 1678 ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile)); 1679 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t)); 1680 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t)); 1681 #endif 1682 1683 #else /* Z_SOLO */ 1684 1685 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t)); 1686 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t)); 1687 1688 #endif /* !Z_SOLO */ 1689 1690 /* hack for buggy compilers */ 1691 #if !defined(ZUTIL_H) && !defined(NO_DUMMY_DECL) 1692 struct internal_state { 1693 int dummy; 1694 }; 1695 #endif 1696 1697 /* undocumented functions */ 1698 ZEXTERN const char *ZEXPORT zError OF((int)); 1699 ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp)); 1700 ZEXTERN const z_crc_t FAR *ZEXPORT get_crc_table OF((void)); 1701 ZEXTERN int ZEXPORT inflateUndermine OF((z_streamp, int)); 1702 ZEXTERN int ZEXPORT inflateResetKeep OF((z_streamp)); 1703 ZEXTERN int ZEXPORT deflateResetKeep OF((z_streamp)); 1704 #if defined(_WIN32) && !defined(Z_SOLO) 1705 ZEXTERN gzFile ZEXPORT gzopen_w OF((const wchar_t * path, const char *mode)); 1706 #endif 1707 #if defined(STDC) || defined(Z_HAVE_STDARG_H) 1708 #ifndef Z_SOLO 1709 ZEXTERN int ZEXPORTVA gzvprintf Z_ARG((gzFile file, const char *format, va_list va)); 1710 #endif 1711 #endif 1712 1713 #ifdef __cplusplus 1714 } 1715 #endif 1716 #endif /* ZLIB_H */