1 /* zlib.h -- interface of the 'zlib' general purpose compression library 2 version 1.2.5, April 19th, 2010 3 4 Copyright (C) 1995-2010 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 (at) gzip.org madler (at) 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://www.ietf.org/rfc/rfc1950.txt 28 (zlib format), rfc1951.txt (deflate format) and rfc1952.txt (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 "1.2.5" 41 #define ZLIB_VERNUM 0x1250 42 #define ZLIB_VER_MAJOR 1 43 #define ZLIB_VER_MINOR 2 44 #define ZLIB_VER_REVISION 5 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 streams in memory as well. 69 70 The zlib format was designed to be compact and fast for use in memory 71 and on communications channels. The gzip format was designed for single- 72 file compression on file systems, has a larger header than zlib to maintain 73 directory information, and uses a different, slower check method than zlib. 74 75 The library does not install any signal handler. The decoder checks 76 the consistency of the compressed data, so the library should never crash 77 even in case of corrupted input. 78 */ 79 80 typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size)); 81 typedef void (*free_func) OF((voidpf opaque, voidpf address)); 82 83 struct internal_state; 84 85 typedef struct z_stream_s { 86 Bytef *next_in; /* next input byte */ 87 uInt avail_in; /* number of bytes available at next_in */ 88 uLong total_in; /* total nb of input bytes read so far */ 89 90 Bytef *next_out; /* next output byte should be put there */ 91 uInt avail_out; /* remaining free space at next_out */ 92 uLong total_out; /* total nb of bytes output so far */ 93 94 char *msg; /* last error message, NULL if no error */ 95 struct internal_state FAR *state; /* not visible by applications */ 96 97 alloc_func zalloc; /* used to allocate the internal state */ 98 free_func zfree; /* used to free the internal state */ 99 voidpf opaque; /* private data object passed to zalloc and zfree */ 100 101 int data_type; /* best guess about the data type: binary or text */ 102 uLong adler; /* adler32 value of the uncompressed data */ 103 uLong reserved; /* reserved for future use */ 104 } z_stream; 105 106 typedef z_stream FAR *z_streamp; 107 108 /* 109 gzip header information passed to and from zlib routines. See RFC 1952 110 for more details on the meanings of these fields. 111 */ 112 typedef struct gz_header_s { 113 int text; /* true if compressed data believed to be text */ 114 uLong time; /* modification time */ 115 int xflags; /* extra flags (not used when writing a gzip file) */ 116 int os; /* operating system */ 117 Bytef *extra; /* pointer to extra field or Z_NULL if none */ 118 uInt extra_len; /* extra field length (valid if extra != Z_NULL) */ 119 uInt extra_max; /* space at extra (only when reading header) */ 120 Bytef *name; /* pointer to zero-terminated file name or Z_NULL */ 121 uInt name_max; /* space at name (only when reading header) */ 122 Bytef *comment; /* pointer to zero-terminated comment or Z_NULL */ 123 uInt comm_max; /* space at comment (only when reading header) */ 124 int hcrc; /* true if there was or will be a header crc */ 125 int done; /* true when done reading gzip header (not used 126 when writing a gzip file) */ 127 } gz_header; 128 129 typedef gz_header FAR *gz_headerp; 130 131 /* 132 The application must update next_in and avail_in when avail_in has dropped 133 to zero. It must update next_out and avail_out when avail_out has dropped 134 to zero. The application must initialize zalloc, zfree and opaque before 135 calling the init function. All other fields are set by the compression 136 library and must not be updated by the application. 137 138 The opaque value provided by the application will be passed as the first 139 parameter for calls of zalloc and zfree. This can be useful for custom 140 memory management. The compression library attaches no meaning to the 141 opaque value. 142 143 zalloc must return Z_NULL if there is not enough memory for the object. 144 If zlib is used in a multi-threaded application, zalloc and zfree must be 145 thread safe. 146 147 On 16-bit systems, the functions zalloc and zfree must be able to allocate 148 exactly 65536 bytes, but will not be required to allocate more than this if 149 the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, pointers 150 returned by zalloc for objects of exactly 65536 bytes *must* have their 151 offset normalized to zero. The default allocation function provided by this 152 library ensures this (see zutil.c). To reduce memory requirements and avoid 153 any allocation of 64K objects, at the expense of compression ratio, compile 154 the library with -DMAX_WBITS=14 (see zconf.h). 155 156 The fields total_in and total_out can be used for statistics or progress 157 reports. After compression, total_in holds the total size of the 158 uncompressed data and may be saved for use in the decompressor (particularly 159 if the decompressor wants to decompress everything in a single step). 160 */ 161 162 /* constants */ 163 164 #define Z_NO_FLUSH 0 165 #define Z_PARTIAL_FLUSH 1 166 #define Z_SYNC_FLUSH 2 167 #define Z_FULL_FLUSH 3 168 #define Z_FINISH 4 169 #define Z_BLOCK 5 170 #define Z_TREES 6 171 /* Allowed flush values; see deflate() and inflate() below for details */ 172 173 #define Z_OK 0 174 #define Z_STREAM_END 1 175 #define Z_NEED_DICT 2 176 #define Z_ERRNO (-1) 177 #define Z_STREAM_ERROR (-2) 178 #define Z_DATA_ERROR (-3) 179 #define Z_MEM_ERROR (-4) 180 #define Z_BUF_ERROR (-5) 181 #define Z_VERSION_ERROR (-6) 182 /* Return codes for the compression/decompression functions. Negative values 183 * are errors, positive values are used for special but normal events. 184 */ 185 186 #define Z_NO_COMPRESSION 0 187 #define Z_BEST_SPEED 1 188 #define Z_BEST_COMPRESSION 9 189 #define Z_DEFAULT_COMPRESSION (-1) 190 /* compression levels */ 191 192 #define Z_FILTERED 1 193 #define Z_HUFFMAN_ONLY 2 194 #define Z_RLE 3 195 #define Z_FIXED 4 196 #define Z_DEFAULT_STRATEGY 0 197 /* compression strategy; see deflateInit2() below for details */ 198 199 #define Z_BINARY 0 200 #define Z_TEXT 1 201 #define Z_ASCII Z_TEXT /* for compatibility with 1.2.2 and earlier */ 202 #define Z_UNKNOWN 2 203 /* Possible values of the data_type field (though see inflate()) */ 204 205 #define Z_DEFLATED 8 206 /* The deflate compression method (the only one supported in this version) */ 207 208 #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */ 209 210 #define zlib_version zlibVersion() 211 /* for compatibility with versions < 1.0.2 */ 212 213 214 /* basic functions */ 215 216 ZEXTERN const char * ZEXPORT zlibVersion OF((void)); 217 /* The application can compare zlibVersion and ZLIB_VERSION for consistency. 218 If the first character differs, the library code actually used is not 219 compatible with the zlib.h header file used by the application. This check 220 is automatically made by deflateInit and inflateInit. 221 */ 222 223 /* 224 ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level)); 225 226 Initializes the internal stream state for compression. The fields 227 zalloc, zfree and opaque must be initialized before by the caller. If 228 zalloc and zfree are set to Z_NULL, deflateInit updates them to use default 229 allocation functions. 230 231 The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9: 232 1 gives best speed, 9 gives best compression, 0 gives no compression at all 233 (the input data is simply copied a block at a time). Z_DEFAULT_COMPRESSION 234 requests a default compromise between speed and compression (currently 235 equivalent to level 6). 236 237 deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough 238 memory, Z_STREAM_ERROR if level is not a valid compression level, or 239 Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible 240 with the version assumed by the caller (ZLIB_VERSION). msg is set to null 241 if there is no error message. deflateInit does not perform any compression: 242 this will be done by deflate(). 243 */ 244 245 246 ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush)); 247 /* 248 deflate compresses as much data as possible, and stops when the input 249 buffer becomes empty or the output buffer becomes full. It may introduce 250 some output latency (reading input without producing any output) except when 251 forced to flush. 252 253 The detailed semantics are as follows. deflate performs one or both of the 254 following actions: 255 256 - Compress more input starting at next_in and update next_in and avail_in 257 accordingly. If not all input can be processed (because there is not 258 enough room in the output buffer), next_in and avail_in are updated and 259 processing will resume at this point for the next call of deflate(). 260 261 - Provide more output starting at next_out and update next_out and avail_out 262 accordingly. This action is forced if the parameter flush is non zero. 263 Forcing flush frequently degrades the compression ratio, so this parameter 264 should be set only when necessary (in interactive applications). Some 265 output may be provided even if flush is not set. 266 267 Before the call of deflate(), the application should ensure that at least 268 one of the actions is possible, by providing more input and/or consuming more 269 output, and updating avail_in or avail_out accordingly; avail_out should 270 never be zero before the call. The application can consume the compressed 271 output when it wants, for example when the output buffer is full (avail_out 272 == 0), or after each call of deflate(). If deflate returns Z_OK and with 273 zero avail_out, it must be called again after making room in the output 274 buffer because there might be more output pending. 275 276 Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to 277 decide how much data to accumulate before producing output, in order to 278 maximize compression. 279 280 If the parameter flush is set to Z_SYNC_FLUSH, all pending output is 281 flushed to the output buffer and the output is aligned on a byte boundary, so 282 that the decompressor can get all input data available so far. (In 283 particular avail_in is zero after the call if enough output space has been 284 provided before the call.) Flushing may degrade compression for some 285 compression algorithms and so it should be used only when necessary. This 286 completes the current deflate block and follows it with an empty stored block 287 that is three bits plus filler bits to the next byte, followed by four bytes 288 (00 00 ff ff). 289 290 If flush is set to Z_PARTIAL_FLUSH, all pending output is flushed to the 291 output buffer, but the output is not aligned to a byte boundary. All of the 292 input data so far will be available to the decompressor, as for Z_SYNC_FLUSH. 293 This completes the current deflate block and follows it with an empty fixed 294 codes block that is 10 bits long. This assures that enough bytes are output 295 in order for the decompressor to finish the block before the empty fixed code 296 block. 297 298 If flush is set to Z_BLOCK, a deflate block is completed and emitted, as 299 for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to 300 seven bits of the current block are held to be written as the next byte after 301 the next deflate block is completed. In this case, the decompressor may not 302 be provided enough bits at this point in order to complete decompression of 303 the data provided so far to the compressor. It may need to wait for the next 304 block to be emitted. This is for advanced applications that need to control 305 the emission of deflate blocks. 306 307 If flush is set to Z_FULL_FLUSH, all output is flushed as with 308 Z_SYNC_FLUSH, and the compression state is reset so that decompression can 309 restart from this point if previous compressed data has been damaged or if 310 random access is desired. Using Z_FULL_FLUSH too often can seriously degrade 311 compression. 312 313 If deflate returns with avail_out == 0, this function must be called again 314 with the same value of the flush parameter and more output space (updated 315 avail_out), until the flush is complete (deflate returns with non-zero 316 avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that 317 avail_out is greater than six to avoid repeated flush markers due to 318 avail_out == 0 on return. 319 320 If the parameter flush is set to Z_FINISH, pending input is processed, 321 pending output is flushed and deflate returns with Z_STREAM_END if there was 322 enough output space; if deflate returns with Z_OK, this function must be 323 called again with Z_FINISH and more output space (updated avail_out) but no 324 more input data, until it returns with Z_STREAM_END or an error. After 325 deflate has returned Z_STREAM_END, the only possible operations on the stream 326 are deflateReset or deflateEnd. 327 328 Z_FINISH can be used immediately after deflateInit if all the compression 329 is to be done in a single step. In this case, avail_out must be at least the 330 value returned by deflateBound (see below). If deflate does not return 331 Z_STREAM_END, then it must be called again as described above. 332 333 deflate() sets strm->adler to the adler32 checksum of all input read 334 so far (that is, total_in bytes). 335 336 deflate() may update strm->data_type if it can make a good guess about 337 the input data type (Z_BINARY or Z_TEXT). In doubt, the data is considered 338 binary. This field is only for information purposes and does not affect the 339 compression algorithm in any manner. 340 341 deflate() returns Z_OK if some progress has been made (more input 342 processed or more output produced), Z_STREAM_END if all input has been 343 consumed and all output has been produced (only when flush is set to 344 Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example 345 if next_in or next_out was Z_NULL), Z_BUF_ERROR if no progress is possible 346 (for example avail_in or avail_out was zero). Note that Z_BUF_ERROR is not 347 fatal, and deflate() can be called again with more input and more output 348 space to continue compressing. 349 */ 350 351 352 ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm)); 353 /* 354 All dynamically allocated data structures for this stream are freed. 355 This function discards any unprocessed input and does not flush any pending 356 output. 357 358 deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the 359 stream state was inconsistent, Z_DATA_ERROR if the stream was freed 360 prematurely (some input or output was discarded). In the error case, msg 361 may be set but then points to a static string (which must not be 362 deallocated). 363 */ 364 365 366 /* 367 ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm)); 368 369 Initializes the internal stream state for decompression. The fields 370 next_in, avail_in, zalloc, zfree and opaque must be initialized before by 371 the caller. If next_in is not Z_NULL and avail_in is large enough (the 372 exact value depends on the compression method), inflateInit determines the 373 compression method from the zlib header and allocates all data structures 374 accordingly; otherwise the allocation will be deferred to the first call of 375 inflate. If zalloc and zfree are set to Z_NULL, inflateInit updates them to 376 use default allocation functions. 377 378 inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough 379 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the 380 version assumed by the caller, or Z_STREAM_ERROR if the parameters are 381 invalid, such as a null pointer to the structure. msg is set to null if 382 there is no error message. inflateInit does not perform any decompression 383 apart from possibly reading the zlib header if present: actual decompression 384 will be done by inflate(). (So next_in and avail_in may be modified, but 385 next_out and avail_out are unused and unchanged.) The current implementation 386 of inflateInit() does not process any header information -- that is deferred 387 until inflate() is called. 388 */ 389 390 391 ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush)); 392 /* 393 inflate decompresses as much data as possible, and stops when the input 394 buffer becomes empty or the output buffer becomes full. It may introduce 395 some output latency (reading input without producing any output) except when 396 forced to flush. 397 398 The detailed semantics are as follows. inflate performs one or both of the 399 following actions: 400 401 - Decompress more input starting at next_in and update next_in and avail_in 402 accordingly. If not all input can be processed (because there is not 403 enough room in the output buffer), next_in is updated and processing will 404 resume at this point for the next call of inflate(). 405 406 - Provide more output starting at next_out and update next_out and avail_out 407 accordingly. inflate() provides as much output as possible, until there is 408 no more input data or no more space in the output buffer (see below about 409 the flush parameter). 410 411 Before the call of inflate(), the application should ensure that at least 412 one of the actions is possible, by providing more input and/or consuming more 413 output, and updating the next_* and avail_* values accordingly. The 414 application can consume the uncompressed output when it wants, for example 415 when the output buffer is full (avail_out == 0), or after each call of 416 inflate(). If inflate returns Z_OK and with zero avail_out, it must be 417 called again after making room in the output buffer because there might be 418 more output pending. 419 420 The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, Z_FINISH, 421 Z_BLOCK, or Z_TREES. Z_SYNC_FLUSH requests that inflate() flush as much 422 output as possible to the output buffer. Z_BLOCK requests that inflate() 423 stop if and when it gets to the next deflate block boundary. When decoding 424 the zlib or gzip format, this will cause inflate() to return immediately 425 after the header and before the first block. When doing a raw inflate, 426 inflate() will go ahead and process the first block, and will return when it 427 gets to the end of that block, or when it runs out of data. 428 429 The Z_BLOCK option assists in appending to or combining deflate streams. 430 Also to assist in this, on return inflate() will set strm->data_type to the 431 number of unused bits in the last byte taken from strm->next_in, plus 64 if 432 inflate() is currently decoding the last block in the deflate stream, plus 433 128 if inflate() returned immediately after decoding an end-of-block code or 434 decoding the complete header up to just before the first byte of the deflate 435 stream. The end-of-block will not be indicated until all of the uncompressed 436 data from that block has been written to strm->next_out. The number of 437 unused bits may in general be greater than seven, except when bit 7 of 438 data_type is set, in which case the number of unused bits will be less than 439 eight. data_type is set as noted here every time inflate() returns for all 440 flush options, and so can be used to determine the amount of currently 441 consumed input in bits. 442 443 The Z_TREES option behaves as Z_BLOCK does, but it also returns when the 444 end of each deflate block header is reached, before any actual data in that 445 block is decoded. This allows the caller to determine the length of the 446 deflate block header for later use in random access within a deflate block. 447 256 is added to the value of strm->data_type when inflate() returns 448 immediately after reaching the end of the deflate block header. 449 450 inflate() should normally be called until it returns Z_STREAM_END or an 451 error. However if all decompression is to be performed in a single step (a 452 single call of inflate), the parameter flush should be set to Z_FINISH. In 453 this case all pending input is processed and all pending output is flushed; 454 avail_out must be large enough to hold all the uncompressed data. (The size 455 of the uncompressed data may have been saved by the compressor for this 456 purpose.) The next operation on this stream must be inflateEnd to deallocate 457 the decompression state. The use of Z_FINISH is never required, but can be 458 used to inform inflate that a faster approach may be used for the single 459 inflate() call. 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 only effect of the flush parameter in this implementation 464 is on the return value of inflate(), as noted below, or when it returns early 465 because Z_BLOCK or Z_TREES is used. 466 467 If a preset dictionary is needed after this call (see inflateSetDictionary 468 below), inflate sets strm->adler to the adler32 checksum of the dictionary 469 chosen by the compressor and returns Z_NEED_DICT; otherwise it sets 470 strm->adler to the adler32 checksum of all output produced so far (that is, 471 total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described 472 below. At the end of the stream, inflate() checks that its computed adler32 473 checksum is equal to that saved by the compressor and returns Z_STREAM_END 474 only if the checksum is correct. 475 476 inflate() can decompress and check either zlib-wrapped or gzip-wrapped 477 deflate data. The header type is detected automatically, if requested when 478 initializing with inflateInit2(). Any information contained in the gzip 479 header is not retained, so applications that need that information should 480 instead use raw inflate, see inflateInit2() below, or inflateBack() and 481 perform their own processing of the gzip header and trailer. 482 483 inflate() returns Z_OK if some progress has been made (more input processed 484 or more output produced), Z_STREAM_END if the end of the compressed data has 485 been reached and all uncompressed output has been produced, Z_NEED_DICT if a 486 preset dictionary is needed at this point, Z_DATA_ERROR if the input data was 487 corrupted (input stream not conforming to the zlib format or incorrect check 488 value), Z_STREAM_ERROR if the stream structure was inconsistent (for example 489 next_in or next_out was Z_NULL), Z_MEM_ERROR if there was not enough memory, 490 Z_BUF_ERROR if no progress is possible or if there was not enough room in the 491 output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and 492 inflate() can be called again with more input and more output space to 493 continue decompressing. If Z_DATA_ERROR is returned, the application may 494 then call inflateSync() to look for a good compression block if a partial 495 recovery of the data is desired. 496 */ 497 498 499 ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm)); 500 /* 501 All dynamically allocated data structures for this stream are freed. 502 This function discards any unprocessed input and does not flush any pending 503 output. 504 505 inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state 506 was inconsistent. In the error case, msg may be set but then points to a 507 static string (which must not be deallocated). 508 */ 509 510 511 /* Advanced functions */ 512 513 /* 514 The following functions are needed only in some special applications. 515 */ 516 517 /* 518 ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm, 519 int level, 520 int method, 521 int windowBits, 522 int memLevel, 523 int strategy)); 524 525 This is another version of deflateInit with more compression options. The 526 fields next_in, zalloc, zfree and opaque must be initialized before by the 527 caller. 528 529 The method parameter is the compression method. It must be Z_DEFLATED in 530 this version of the library. 531 532 The windowBits parameter is the base two logarithm of the window size 533 (the size of the history buffer). It should be in the range 8..15 for this 534 version of the library. Larger values of this parameter result in better 535 compression at the expense of memory usage. The default value is 15 if 536 deflateInit is used instead. 537 538 windowBits can also be -8..-15 for raw deflate. In this case, -windowBits 539 determines the window size. deflate() will then generate raw deflate data 540 with no zlib header or trailer, and will not compute an adler32 check value. 541 542 windowBits can also be greater than 15 for optional gzip encoding. Add 543 16 to windowBits to write a simple gzip header and trailer around the 544 compressed data instead of a zlib wrapper. The gzip header will have no 545 file name, no extra data, no comment, no modification time (set to zero), no 546 header crc, and the operating system will be set to 255 (unknown). If a 547 gzip stream is being written, strm->adler is a crc32 instead of an adler32. 548 549 The memLevel parameter specifies how much memory should be allocated 550 for the internal compression state. memLevel=1 uses minimum memory but is 551 slow and reduces compression ratio; memLevel=9 uses maximum memory for 552 optimal speed. The default value is 8. See zconf.h for total memory usage 553 as a function of windowBits and memLevel. 554 555 The strategy parameter is used to tune the compression algorithm. Use the 556 value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a 557 filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no 558 string match), or Z_RLE to limit match distances to one (run-length 559 encoding). Filtered data consists mostly of small values with a somewhat 560 random distribution. In this case, the compression algorithm is tuned to 561 compress them better. The effect of Z_FILTERED is to force more Huffman 562 coding and less string matching; it is somewhat intermediate between 563 Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as 564 fast as Z_HUFFMAN_ONLY, but give better compression for PNG image data. The 565 strategy parameter only affects the compression ratio but not the 566 correctness of the compressed output even if it is not set appropriately. 567 Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler 568 decoder for special applications. 569 570 deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 571 memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid 572 method), or Z_VERSION_ERROR if the zlib library version (zlib_version) is 573 incompatible with the version assumed by the caller (ZLIB_VERSION). msg is 574 set to null if there is no error message. deflateInit2 does not perform any 575 compression: this will be done by deflate(). 576 */ 577 578 ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm, 579 const Bytef *dictionary, 580 uInt dictLength)); 581 /* 582 Initializes the compression dictionary from the given byte sequence 583 without producing any compressed output. This function must be called 584 immediately after deflateInit, deflateInit2 or deflateReset, before any call 585 of deflate. The compressor and decompressor must use exactly the same 586 dictionary (see inflateSetDictionary). 587 588 The dictionary should consist of strings (byte sequences) that are likely 589 to be encountered later in the data to be compressed, with the most commonly 590 used strings preferably put towards the end of the dictionary. Using a 591 dictionary is most useful when the data to be compressed is short and can be 592 predicted with good accuracy; the data can then be compressed better than 593 with the default empty dictionary. 594 595 Depending on the size of the compression data structures selected by 596 deflateInit or deflateInit2, a part of the dictionary may in effect be 597 discarded, for example if the dictionary is larger than the window size 598 provided in deflateInit or deflateInit2. Thus the strings most likely to be 599 useful should be put at the end of the dictionary, not at the front. In 600 addition, the current implementation of deflate will use at most the window 601 size minus 262 bytes of the provided dictionary. 602 603 Upon return of this function, strm->adler is set to the adler32 value 604 of the dictionary; the decompressor may later use this value to determine 605 which dictionary has been used by the compressor. (The adler32 value 606 applies to the whole dictionary even if only a subset of the dictionary is 607 actually used by the compressor.) If a raw deflate was requested, then the 608 adler32 value is not computed and strm->adler is not set. 609 610 deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a 611 parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is 612 inconsistent (for example if deflate has already been called for this stream 613 or if the compression method is bsort). deflateSetDictionary does not 614 perform any compression: this will be done by deflate(). 615 */ 616 617 ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest, 618 z_streamp source)); 619 /* 620 Sets the destination stream as a complete copy of the source stream. 621 622 This function can be useful when several compression strategies will be 623 tried, for example when there are several ways of pre-processing the input 624 data with a filter. The streams that will be discarded should then be freed 625 by calling deflateEnd. Note that deflateCopy duplicates the internal 626 compression state which can be quite large, so this strategy is slow and can 627 consume lots of memory. 628 629 deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not 630 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent 631 (such as zalloc being Z_NULL). msg is left unchanged in both source and 632 destination. 633 */ 634 635 ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm)); 636 /* 637 This function is equivalent to deflateEnd followed by deflateInit, 638 but does not free and reallocate all the internal compression state. The 639 stream will keep the same compression level and any other attributes that 640 may have been set by deflateInit2. 641 642 deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source 643 stream state was inconsistent (such as zalloc or state being Z_NULL). 644 */ 645 646 ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm, 647 int level, 648 int strategy)); 649 /* 650 Dynamically update the compression level and compression strategy. The 651 interpretation of level and strategy is as in deflateInit2. This can be 652 used to switch between compression and straight copy of the input data, or 653 to switch to a different kind of input data requiring a different strategy. 654 If the compression level is changed, the input available so far is 655 compressed with the old level (and may be flushed); the new level will take 656 effect only at the next call of deflate(). 657 658 Before the call of deflateParams, the stream state must be set as for 659 a call of deflate(), since the currently available input may have to be 660 compressed and flushed. In particular, strm->avail_out must be non-zero. 661 662 deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source 663 stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR if 664 strm->avail_out was zero. 665 */ 666 667 ZEXTERN int ZEXPORT deflateTune OF((z_streamp strm, 668 int good_length, 669 int max_lazy, 670 int nice_length, 671 int max_chain)); 672 /* 673 Fine tune deflate's internal compression parameters. This should only be 674 used by someone who understands the algorithm used by zlib's deflate for 675 searching for the best matching string, and even then only by the most 676 fanatic optimizer trying to squeeze out the last compressed bit for their 677 specific input data. Read the deflate.c source code for the meaning of the 678 max_lazy, good_length, nice_length, and max_chain parameters. 679 680 deflateTune() can be called after deflateInit() or deflateInit2(), and 681 returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream. 682 */ 683 684 ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm, 685 uLong sourceLen)); 686 /* 687 deflateBound() returns an upper bound on the compressed size after 688 deflation of sourceLen bytes. It must be called after deflateInit() or 689 deflateInit2(), and after deflateSetHeader(), if used. This would be used 690 to allocate an output buffer for deflation in a single pass, and so would be 691 called before deflate(). 692 */ 693 694 ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm, 695 int bits, 696 int value)); 697 /* 698 deflatePrime() inserts bits in the deflate output stream. The intent 699 is that this function is used to start off the deflate output with the bits 700 leftover from a previous deflate stream when appending to it. As such, this 701 function can only be used for raw deflate, and must be used before the first 702 deflate() call after a deflateInit2() or deflateReset(). bits must be less 703 than or equal to 16, and that many of the least significant bits of value 704 will be inserted in the output. 705 706 deflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source 707 stream state was inconsistent. 708 */ 709 710 ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm, 711 gz_headerp head)); 712 /* 713 deflateSetHeader() provides gzip header information for when a gzip 714 stream is requested by deflateInit2(). deflateSetHeader() may be called 715 after deflateInit2() or deflateReset() and before the first call of 716 deflate(). The text, time, os, extra field, name, and comment information 717 in the provided gz_header structure are written to the gzip header (xflag is 718 ignored -- the extra flags are set according to the compression level). The 719 caller must assure that, if not Z_NULL, name and comment are terminated with 720 a zero byte, and that if extra is not Z_NULL, that extra_len bytes are 721 available there. If hcrc is true, a gzip header crc is included. Note that 722 the current versions of the command-line version of gzip (up through version 723 1.3.x) do not support header crc's, and will report that it is a "multi-part 724 gzip file" and give up. 725 726 If deflateSetHeader is not used, the default gzip header has text false, 727 the time set to zero, and os set to 255, with no extra, name, or comment 728 fields. The gzip header is returned to the default state by deflateReset(). 729 730 deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source 731 stream state was inconsistent. 732 */ 733 734 /* 735 ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm, 736 int windowBits)); 737 738 This is another version of inflateInit with an extra parameter. The 739 fields next_in, avail_in, zalloc, zfree and opaque must be initialized 740 before by the caller. 741 742 The windowBits parameter is the base two logarithm of the maximum window 743 size (the size of the history buffer). It should be in the range 8..15 for 744 this version of the library. The default value is 15 if inflateInit is used 745 instead. windowBits must be greater than or equal to the windowBits value 746 provided to deflateInit2() while compressing, or it must be equal to 15 if 747 deflateInit2() was not used. If a compressed stream with a larger window 748 size is given as input, inflate() will return with the error code 749 Z_DATA_ERROR instead of trying to allocate a larger window. 750 751 windowBits can also be zero to request that inflate use the window size in 752 the zlib header of the compressed stream. 753 754 windowBits can also be -8..-15 for raw inflate. In this case, -windowBits 755 determines the window size. inflate() will then process raw deflate data, 756 not looking for a zlib or gzip header, not generating a check value, and not 757 looking for any check values for comparison at the end of the stream. This 758 is for use with other formats that use the deflate compressed data format 759 such as zip. Those formats provide their own check values. If a custom 760 format is developed using the raw deflate format for compressed data, it is 761 recommended that a check value such as an adler32 or a crc32 be applied to 762 the uncompressed data as is done in the zlib, gzip, and zip formats. For 763 most applications, the zlib format should be used as is. Note that comments 764 above on the use in deflateInit2() applies to the magnitude of windowBits. 765 766 windowBits can also be greater than 15 for optional gzip decoding. Add 767 32 to windowBits to enable zlib and gzip decoding with automatic header 768 detection, or add 16 to decode only the gzip format (the zlib format will 769 return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is a 770 crc32 instead of an adler32. 771 772 inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 773 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the 774 version assumed by the caller, or Z_STREAM_ERROR if the parameters are 775 invalid, such as a null pointer to the structure. msg is set to null if 776 there is no error message. inflateInit2 does not perform any decompression 777 apart from possibly reading the zlib header if present: actual decompression 778 will be done by inflate(). (So next_in and avail_in may be modified, but 779 next_out and avail_out are unused and unchanged.) The current implementation 780 of inflateInit2() does not process any header information -- that is 781 deferred until inflate() is called. 782 */ 783 784 ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm, 785 const Bytef *dictionary, 786 uInt dictLength)); 787 /* 788 Initializes the decompression dictionary from the given uncompressed byte 789 sequence. This function must be called immediately after a call of inflate, 790 if that call returned Z_NEED_DICT. The dictionary chosen by the compressor 791 can be determined from the adler32 value returned by that call of inflate. 792 The compressor and decompressor must use exactly the same dictionary (see 793 deflateSetDictionary). For raw inflate, this function can be called 794 immediately after inflateInit2() or inflateReset() and before any call of 795 inflate() to set the dictionary. The application must insure that the 796 dictionary that was used for compression is provided. 797 798 inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a 799 parameter is invalid (e.g. dictionary being Z_NULL) or the stream state is 800 inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the 801 expected one (incorrect adler32 value). inflateSetDictionary does not 802 perform any decompression: this will be done by subsequent calls of 803 inflate(). 804 */ 805 806 ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm)); 807 /* 808 Skips invalid compressed data until a full flush point (see above the 809 description of deflate with Z_FULL_FLUSH) can be found, or until all 810 available input is skipped. No output is provided. 811 812 inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR 813 if no more input was provided, Z_DATA_ERROR if no flush point has been 814 found, or Z_STREAM_ERROR if the stream structure was inconsistent. In the 815 success case, the application may save the current current value of total_in 816 which indicates where valid compressed data was found. In the error case, 817 the application may repeatedly call inflateSync, providing more input each 818 time, until success or end of the input data. 819 */ 820 821 ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest, 822 z_streamp source)); 823 /* 824 Sets the destination stream as a complete copy of the source stream. 825 826 This function can be useful when randomly accessing a large stream. The 827 first pass through the stream can periodically record the inflate state, 828 allowing restarting inflate at those points when randomly accessing the 829 stream. 830 831 inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not 832 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent 833 (such as zalloc being Z_NULL). msg is left unchanged in both source and 834 destination. 835 */ 836 837 ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm)); 838 /* 839 This function is equivalent to inflateEnd followed by inflateInit, 840 but does not free and reallocate all the internal decompression state. The 841 stream will keep attributes that may have been set by inflateInit2. 842 843 inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source 844 stream state was inconsistent (such as zalloc or state being Z_NULL). 845 */ 846 847 ZEXTERN int ZEXPORT inflateReset2 OF((z_streamp strm, 848 int windowBits)); 849 /* 850 This function is the same as inflateReset, but it also permits changing 851 the wrap and window size requests. The windowBits parameter is interpreted 852 the same as it is for inflateInit2. 853 854 inflateReset2 returns Z_OK if success, or Z_STREAM_ERROR if the source 855 stream state was inconsistent (such as zalloc or state being Z_NULL), or if 856 the windowBits parameter is invalid. 857 */ 858 859 ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm, 860 int bits, 861 int value)); 862 /* 863 This function inserts bits in the inflate input stream. The intent is 864 that this function is used to start inflating at a bit position in the 865 middle of a byte. The provided bits will be used before any bytes are used 866 from next_in. This function should only be used with raw inflate, and 867 should be used before the first inflate() call after inflateInit2() or 868 inflateReset(). bits must be less than or equal to 16, and that many of the 869 least significant bits of value will be inserted in the input. 870 871 If bits is negative, then the input stream bit buffer is emptied. Then 872 inflatePrime() can be called again to put bits in the buffer. This is used 873 to clear out bits leftover after feeding inflate a block description prior 874 to feeding inflate codes. 875 876 inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source 877 stream state was inconsistent. 878 */ 879 880 ZEXTERN long ZEXPORT inflateMark OF((z_streamp strm)); 881 /* 882 This function returns two values, one in the lower 16 bits of the return 883 value, and the other in the remaining upper bits, obtained by shifting the 884 return value down 16 bits. If the upper value is -1 and the lower value is 885 zero, then inflate() is currently decoding information outside of a block. 886 If the upper value is -1 and the lower value is non-zero, then inflate is in 887 the middle of a stored block, with the lower value equaling the number of 888 bytes from the input remaining to copy. If the upper value is not -1, then 889 it is the number of bits back from the current bit position in the input of 890 the code (literal or length/distance pair) currently being processed. In 891 that case the lower value is the number of bytes already emitted for that 892 code. 893 894 A code is being processed if inflate is waiting for more input to complete 895 decoding of the code, or if it has completed decoding but is waiting for 896 more output space to write the literal or match data. 897 898 inflateMark() is used to mark locations in the input data for random 899 access, which may be at bit positions, and to note those cases where the 900 output of a code may span boundaries of random access blocks. The current 901 location in the input stream can be determined from avail_in and data_type 902 as noted in the description for the Z_BLOCK flush parameter for inflate. 903 904 inflateMark returns the value noted above or -1 << 16 if the provided 905 source stream state was inconsistent. 906 */ 907 908 ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm, 909 gz_headerp head)); 910 /* 911 inflateGetHeader() requests that gzip header information be stored in the 912 provided gz_header structure. inflateGetHeader() may be called after 913 inflateInit2() or inflateReset(), and before the first call of inflate(). 914 As inflate() processes the gzip stream, head->done is zero until the header 915 is completed, at which time head->done is set to one. If a zlib stream is 916 being decoded, then head->done is set to -1 to indicate that there will be 917 no gzip header information forthcoming. Note that Z_BLOCK or Z_TREES can be 918 used to force inflate() to return immediately after header processing is 919 complete and before any actual data is decompressed. 920 921 The text, time, xflags, and os fields are filled in with the gzip header 922 contents. hcrc is set to true if there is a header CRC. (The header CRC 923 was valid if done is set to one.) If extra is not Z_NULL, then extra_max 924 contains the maximum number of bytes to write to extra. Once done is true, 925 extra_len contains the actual extra field length, and extra contains the 926 extra field, or that field truncated if extra_max is less than extra_len. 927 If name is not Z_NULL, then up to name_max characters are written there, 928 terminated with a zero unless the length is greater than name_max. If 929 comment is not Z_NULL, then up to comm_max characters are written there, 930 terminated with a zero unless the length is greater than comm_max. When any 931 of extra, name, or comment are not Z_NULL and the respective field is not 932 present in the header, then that field is set to Z_NULL to signal its 933 absence. This allows the use of deflateSetHeader() with the returned 934 structure to duplicate the header. However if those fields are set to 935 allocated memory, then the application will need to save those pointers 936 elsewhere so that they can be eventually freed. 937 938 If inflateGetHeader is not used, then the header information is simply 939 discarded. The header is always checked for validity, including the header 940 CRC if present. inflateReset() will reset the process to discard the header 941 information. The application would need to call inflateGetHeader() again to 942 retrieve the header from the next gzip stream. 943 944 inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source 945 stream state was inconsistent. 946 */ 947 948 /* 949 ZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits, 950 unsigned char FAR *window)); 951 952 Initialize the internal stream state for decompression using inflateBack() 953 calls. The fields zalloc, zfree and opaque in strm must be initialized 954 before the call. If zalloc and zfree are Z_NULL, then the default library- 955 derived memory allocation routines are used. windowBits is the base two 956 logarithm of the window size, in the range 8..15. window is a caller 957 supplied buffer of that size. Except for special applications where it is 958 assured that deflate was used with small window sizes, windowBits must be 15 959 and a 32K byte window must be supplied to be able to decompress general 960 deflate streams. 961 962 See inflateBack() for the usage of these routines. 963 964 inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of 965 the paramaters are invalid, Z_MEM_ERROR if the internal state could not be 966 allocated, or Z_VERSION_ERROR if the version of the library does not match 967 the version of the header file. 968 */ 969 970 typedef unsigned (*in_func) OF((void FAR *, unsigned char FAR * FAR *)); 971 typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned)); 972 973 ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm, 974 in_func in, void FAR *in_desc, 975 out_func out, void FAR *out_desc)); 976 /* 977 inflateBack() does a raw inflate with a single call using a call-back 978 interface for input and output. This is more efficient than inflate() for 979 file i/o applications in that it avoids copying between the output and the 980 sliding window by simply making the window itself the output buffer. This 981 function trusts the application to not change the output buffer passed by 982 the output function, at least until inflateBack() returns. 983 984 inflateBackInit() must be called first to allocate the internal state 985 and to initialize the state with the user-provided window buffer. 986 inflateBack() may then be used multiple times to inflate a complete, raw 987 deflate stream with each call. inflateBackEnd() is then called to free the 988 allocated state. 989 990 A raw deflate stream is one with no zlib or gzip header or trailer. 991 This routine would normally be used in a utility that reads zip or gzip 992 files and writes out uncompressed files. The utility would decode the 993 header and process the trailer on its own, hence this routine expects only 994 the raw deflate stream to decompress. This is different from the normal 995 behavior of inflate(), which expects either a zlib or gzip header and 996 trailer around the deflate stream. 997 998 inflateBack() uses two subroutines supplied by the caller that are then 999 called by inflateBack() for input and output. inflateBack() calls those 1000 routines until it reads a complete deflate stream and writes out all of the 1001 uncompressed data, or until it encounters an error. The function's 1002 parameters and return types are defined above in the in_func and out_func 1003 typedefs. inflateBack() will call in(in_desc, &buf) which should return the 1004 number of bytes of provided input, and a pointer to that input in buf. If 1005 there is no input available, in() must return zero--buf is ignored in that 1006 case--and inflateBack() will return a buffer error. inflateBack() will call 1007 out(out_desc, buf, len) to write the uncompressed data buf[0..len-1]. out() 1008 should return zero on success, or non-zero on failure. If out() returns 1009 non-zero, inflateBack() will return with an error. Neither in() nor out() 1010 are permitted to change the contents of the window provided to 1011 inflateBackInit(), which is also the buffer that out() uses to write from. 1012 The length written by out() will be at most the window size. Any non-zero 1013 amount of input may be provided by in(). 1014 1015 For convenience, inflateBack() can be provided input on the first call by 1016 setting strm->next_in and strm->avail_in. If that input is exhausted, then 1017 in() will be called. Therefore strm->next_in must be initialized before 1018 calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called 1019 immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in 1020 must also be initialized, and then if strm->avail_in is not zero, input will 1021 initially be taken from strm->next_in[0 .. strm->avail_in - 1]. 1022 1023 The in_desc and out_desc parameters of inflateBack() is passed as the 1024 first parameter of in() and out() respectively when they are called. These 1025 descriptors can be optionally used to pass any information that the caller- 1026 supplied in() and out() functions need to do their job. 1027 1028 On return, inflateBack() will set strm->next_in and strm->avail_in to 1029 pass back any unused input that was provided by the last in() call. The 1030 return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR 1031 if in() or out() returned an error, Z_DATA_ERROR if there was a format error 1032 in the deflate stream (in which case strm->msg is set to indicate the nature 1033 of the error), or Z_STREAM_ERROR if the stream was not properly initialized. 1034 In the case of Z_BUF_ERROR, an input or output error can be distinguished 1035 using strm->next_in which will be Z_NULL only if in() returned an error. If 1036 strm->next_in is not Z_NULL, then the Z_BUF_ERROR was due to out() returning 1037 non-zero. (in() will always be called before out(), so strm->next_in is 1038 assured to be defined if out() returns non-zero.) Note that inflateBack() 1039 cannot return Z_OK. 1040 */ 1041 1042 ZEXTERN int ZEXPORT inflateBackEnd OF((z_streamp strm)); 1043 /* 1044 All memory allocated by inflateBackInit() is freed. 1045 1046 inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream 1047 state was inconsistent. 1048 */ 1049 1050 ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void)); 1051 /* Return flags indicating compile-time options. 1052 1053 Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other: 1054 1.0: size of uInt 1055 3.2: size of uLong 1056 5.4: size of voidpf (pointer) 1057 7.6: size of z_off_t 1058 1059 Compiler, assembler, and debug options: 1060 8: DEBUG 1061 9: ASMV or ASMINF -- use ASM code 1062 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention 1063 11: 0 (reserved) 1064 1065 One-time table building (smaller code, but not thread-safe if true): 1066 12: BUILDFIXED -- build static block decoding tables when needed 1067 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed 1068 14,15: 0 (reserved) 1069 1070 Library content (indicates missing functionality): 1071 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking 1072 deflate code when not needed) 1073 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect 1074 and decode gzip streams (to avoid linking crc code) 1075 18-19: 0 (reserved) 1076 1077 Operation variations (changes in library functionality): 1078 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate 1079 21: FASTEST -- deflate algorithm with only one, lowest compression level 1080 22,23: 0 (reserved) 1081 1082 The sprintf variant used by gzprintf (zero is best): 1083 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format 1084 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure! 1085 26: 0 = returns value, 1 = void -- 1 means inferred string length returned 1086 1087 Remainder: 1088 27-31: 0 (reserved) 1089 */ 1090 1091 1092 /* utility functions */ 1093 1094 /* 1095 The following utility functions are implemented on top of the basic 1096 stream-oriented functions. To simplify the interface, some default options 1097 are assumed (compression level and memory usage, standard memory allocation 1098 functions). The source code of these utility functions can be modified if 1099 you need special options. 1100 */ 1101 1102 ZEXTERN int ZEXPORT compress OF((Bytef *dest, uLongf *destLen, 1103 const Bytef *source, uLong sourceLen)); 1104 /* 1105 Compresses the source buffer into the destination buffer. sourceLen is 1106 the byte length of the source buffer. Upon entry, destLen is the total size 1107 of the destination buffer, which must be at least the value returned by 1108 compressBound(sourceLen). Upon exit, destLen is the actual size of the 1109 compressed buffer. 1110 1111 compress returns Z_OK if success, Z_MEM_ERROR if there was not 1112 enough memory, Z_BUF_ERROR if there was not enough room in the output 1113 buffer. 1114 */ 1115 1116 ZEXTERN int ZEXPORT compress2 OF((Bytef *dest, uLongf *destLen, 1117 const Bytef *source, uLong sourceLen, 1118 int level)); 1119 /* 1120 Compresses the source buffer into the destination buffer. The level 1121 parameter has the same meaning as in deflateInit. sourceLen is the byte 1122 length of the source buffer. Upon entry, destLen is the total size of the 1123 destination buffer, which must be at least the value returned by 1124 compressBound(sourceLen). Upon exit, destLen is the actual size of the 1125 compressed buffer. 1126 1127 compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 1128 memory, Z_BUF_ERROR if there was not enough room in the output buffer, 1129 Z_STREAM_ERROR if the level parameter is invalid. 1130 */ 1131 1132 ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen)); 1133 /* 1134 compressBound() returns an upper bound on the compressed size after 1135 compress() or compress2() on sourceLen bytes. It would be used before a 1136 compress() or compress2() call to allocate the destination buffer. 1137 */ 1138 1139 ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen, 1140 const Bytef *source, uLong sourceLen)); 1141 /* 1142 Decompresses the source buffer into the destination buffer. sourceLen is 1143 the byte length of the source buffer. Upon entry, destLen is the total size 1144 of the destination buffer, which must be large enough to hold the entire 1145 uncompressed data. (The size of the uncompressed data must have been saved 1146 previously by the compressor and transmitted to the decompressor by some 1147 mechanism outside the scope of this compression library.) Upon exit, destLen 1148 is the actual size of the uncompressed buffer. 1149 1150 uncompress returns Z_OK if success, Z_MEM_ERROR if there was not 1151 enough memory, Z_BUF_ERROR if there was not enough room in the output 1152 buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete. 1153 */ 1154 1155 1156 /* gzip file access functions */ 1157 1158 /* 1159 This library supports reading and writing files in gzip (.gz) format with 1160 an interface similar to that of stdio, using the functions that start with 1161 "gz". The gzip format is different from the zlib format. gzip is a gzip 1162 wrapper, documented in RFC 1952, wrapped around a deflate stream. 1163 */ 1164 1165 typedef voidp gzFile; /* opaque gzip file descriptor */ 1166 1167 /* 1168 ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode)); 1169 1170 Opens a gzip (.gz) file for reading or writing. The mode parameter is as 1171 in fopen ("rb" or "wb") but can also include a compression level ("wb9") or 1172 a strategy: 'f' for filtered data as in "wb6f", 'h' for Huffman-only 1173 compression as in "wb1h", 'R' for run-length encoding as in "wb1R", or 'F' 1174 for fixed code compression as in "wb9F". (See the description of 1175 deflateInit2 for more information about the strategy parameter.) Also "a" 1176 can be used instead of "w" to request that the gzip stream that will be 1177 written be appended to the file. "+" will result in an error, since reading 1178 and writing to the same gzip file is not supported. 1179 1180 gzopen can be used to read a file which is not in gzip format; in this 1181 case gzread will directly read from the file without decompression. 1182 1183 gzopen returns NULL if the file could not be opened, if there was 1184 insufficient memory to allocate the gzFile state, or if an invalid mode was 1185 specified (an 'r', 'w', or 'a' was not provided, or '+' was provided). 1186 errno can be checked to determine if the reason gzopen failed was that the 1187 file could not be opened. 1188 */ 1189 1190 ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode)); 1191 /* 1192 gzdopen associates a gzFile with the file descriptor fd. File descriptors 1193 are obtained from calls like open, dup, creat, pipe or fileno (if the file 1194 has been previously opened with fopen). The mode parameter is as in gzopen. 1195 1196 The next call of gzclose on the returned gzFile will also close the file 1197 descriptor fd, just like fclose(fdopen(fd, mode)) closes the file descriptor 1198 fd. If you want to keep fd open, use fd = dup(fd_keep); gz = gzdopen(fd, 1199 mode);. The duplicated descriptor should be saved to avoid a leak, since 1200 gzdopen does not close fd if it fails. 1201 1202 gzdopen returns NULL if there was insufficient memory to allocate the 1203 gzFile state, if an invalid mode was specified (an 'r', 'w', or 'a' was not 1204 provided, or '+' was provided), or if fd is -1. The file descriptor is not 1205 used until the next gz* read, write, seek, or close operation, so gzdopen 1206 will not detect if fd is invalid (unless fd is -1). 1207 */ 1208 1209 ZEXTERN int ZEXPORT gzbuffer OF((gzFile file, unsigned size)); 1210 /* 1211 Set the internal buffer size used by this library's functions. The 1212 default buffer size is 8192 bytes. This function must be called after 1213 gzopen() or gzdopen(), and before any other calls that read or write the 1214 file. The buffer memory allocation is always deferred to the first read or 1215 write. Two buffers are allocated, either both of the specified size when 1216 writing, or one of the specified size and the other twice that size when 1217 reading. A larger buffer size of, for example, 64K or 128K bytes will 1218 noticeably increase the speed of decompression (reading). 1219 1220 The new buffer size also affects the maximum length for gzprintf(). 1221 1222 gzbuffer() returns 0 on success, or -1 on failure, such as being called 1223 too late. 1224 */ 1225 1226 ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy)); 1227 /* 1228 Dynamically update the compression level or strategy. See the description 1229 of deflateInit2 for the meaning of these parameters. 1230 1231 gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not 1232 opened for writing. 1233 */ 1234 1235 ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len)); 1236 /* 1237 Reads the given number of uncompressed bytes from the compressed file. If 1238 the input file was not in gzip format, gzread copies the given number of 1239 bytes into the buffer. 1240 1241 After reaching the end of a gzip stream in the input, gzread will continue 1242 to read, looking for another gzip stream, or failing that, reading the rest 1243 of the input file directly without decompression. The entire input file 1244 will be read if gzread is called until it returns less than the requested 1245 len. 1246 1247 gzread returns the number of uncompressed bytes actually read, less than 1248 len for end of file, or -1 for error. 1249 */ 1250 1251 ZEXTERN int ZEXPORT gzwrite OF((gzFile file, 1252 voidpc buf, unsigned len)); 1253 /* 1254 Writes the given number of uncompressed bytes into the compressed file. 1255 gzwrite returns the number of uncompressed bytes written or 0 in case of 1256 error. 1257 */ 1258 1259 ZEXTERN int ZEXPORTVA gzprintf OF((gzFile file, const char *format, ...)); 1260 /* 1261 Converts, formats, and writes the arguments to the compressed file under 1262 control of the format string, as in fprintf. gzprintf returns the number of 1263 uncompressed bytes actually written, or 0 in case of error. The number of 1264 uncompressed bytes written is limited to 8191, or one less than the buffer 1265 size given to gzbuffer(). The caller should assure that this limit is not 1266 exceeded. If it is exceeded, then gzprintf() will return an error (0) with 1267 nothing written. In this case, there may also be a buffer overflow with 1268 unpredictable consequences, which is possible only if zlib was compiled with 1269 the insecure functions sprintf() or vsprintf() because the secure snprintf() 1270 or vsnprintf() functions were not available. This can be determined using 1271 zlibCompileFlags(). 1272 */ 1273 1274 ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s)); 1275 /* 1276 Writes the given null-terminated string to the compressed file, excluding 1277 the terminating null character. 1278 1279 gzputs returns the number of characters written, or -1 in case of error. 1280 */ 1281 1282 ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len)); 1283 /* 1284 Reads bytes from the compressed file until len-1 characters are read, or a 1285 newline character is read and transferred to buf, or an end-of-file 1286 condition is encountered. If any characters are read or if len == 1, the 1287 string is terminated with a null character. If no characters are read due 1288 to an end-of-file or len < 1, then the buffer is left untouched. 1289 1290 gzgets returns buf which is a null-terminated string, or it returns NULL 1291 for end-of-file or in case of error. If there was an error, the contents at 1292 buf are indeterminate. 1293 */ 1294 1295 ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c)); 1296 /* 1297 Writes c, converted to an unsigned char, into the compressed file. gzputc 1298 returns the value that was written, or -1 in case of error. 1299 */ 1300 1301 ZEXTERN int ZEXPORT gzgetc OF((gzFile file)); 1302 /* 1303 Reads one byte from the compressed file. gzgetc returns this byte or -1 1304 in case of end of file or error. 1305 */ 1306 1307 ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file)); 1308 /* 1309 Push one character back onto the stream to be read as the first character 1310 on the next read. At least one character of push-back is allowed. 1311 gzungetc() returns the character pushed, or -1 on failure. gzungetc() will 1312 fail if c is -1, and may fail if a character has been pushed but not read 1313 yet. If gzungetc is used immediately after gzopen or gzdopen, at least the 1314 output buffer size of pushed characters is allowed. (See gzbuffer above.) 1315 The pushed character will be discarded if the stream is repositioned with 1316 gzseek() or gzrewind(). 1317 */ 1318 1319 ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush)); 1320 /* 1321 Flushes all pending output into the compressed file. The parameter flush 1322 is as in the deflate() function. The return value is the zlib error number 1323 (see function gzerror below). gzflush is only permitted when writing. 1324 1325 If the flush parameter is Z_FINISH, the remaining data is written and the 1326 gzip stream is completed in the output. If gzwrite() is called again, a new 1327 gzip stream will be started in the output. gzread() is able to read such 1328 concatented gzip streams. 1329 1330 gzflush should be called only when strictly necessary because it will 1331 degrade compression if called too often. 1332 */ 1333 1334 /* 1335 ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file, 1336 z_off_t offset, int whence)); 1337 1338 Sets the starting position for the next gzread or gzwrite on the given 1339 compressed file. The offset represents a number of bytes in the 1340 uncompressed data stream. The whence parameter is defined as in lseek(2); 1341 the value SEEK_END is not supported. 1342 1343 If the file is opened for reading, this function is emulated but can be 1344 extremely slow. If the file is opened for writing, only forward seeks are 1345 supported; gzseek then compresses a sequence of zeroes up to the new 1346 starting position. 1347 1348 gzseek returns the resulting offset location as measured in bytes from 1349 the beginning of the uncompressed stream, or -1 in case of error, in 1350 particular if the file is opened for writing and the new starting position 1351 would be before the current position. 1352 */ 1353 1354 ZEXTERN int ZEXPORT gzrewind OF((gzFile file)); 1355 /* 1356 Rewinds the given file. This function is supported only for reading. 1357 1358 gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET) 1359 */ 1360 1361 /* 1362 ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file)); 1363 1364 Returns the starting position for the next gzread or gzwrite on the given 1365 compressed file. This position represents a number of bytes in the 1366 uncompressed data stream, and is zero when starting, even if appending or 1367 reading a gzip stream from the middle of a file using gzdopen(). 1368 1369 gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR) 1370 */ 1371 1372 /* 1373 ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile file)); 1374 1375 Returns the current offset in the file being read or written. This offset 1376 includes the count of bytes that precede the gzip stream, for example when 1377 appending or when using gzdopen() for reading. When reading, the offset 1378 does not include as yet unused buffered input. This information can be used 1379 for a progress indicator. On error, gzoffset() returns -1. 1380 */ 1381 1382 ZEXTERN int ZEXPORT gzeof OF((gzFile file)); 1383 /* 1384 Returns true (1) if the end-of-file indicator has been set while reading, 1385 false (0) otherwise. Note that the end-of-file indicator is set only if the 1386 read tried to go past the end of the input, but came up short. Therefore, 1387 just like feof(), gzeof() may return false even if there is no more data to 1388 read, in the event that the last read request was for the exact number of 1389 bytes remaining in the input file. This will happen if the input file size 1390 is an exact multiple of the buffer size. 1391 1392 If gzeof() returns true, then the read functions will return no more data, 1393 unless the end-of-file indicator is reset by gzclearerr() and the input file 1394 has grown since the previous end of file was detected. 1395 */ 1396 1397 ZEXTERN int ZEXPORT gzdirect OF((gzFile file)); 1398 /* 1399 Returns true (1) if file is being copied directly while reading, or false 1400 (0) if file is a gzip stream being decompressed. This state can change from 1401 false to true while reading the input file if the end of a gzip stream is 1402 reached, but is followed by data that is not another gzip stream. 1403 1404 If the input file is empty, gzdirect() will return true, since the input 1405 does not contain a gzip stream. 1406 1407 If gzdirect() is used immediately after gzopen() or gzdopen() it will 1408 cause buffers to be allocated to allow reading the file to determine if it 1409 is a gzip file. Therefore if gzbuffer() is used, it should be called before 1410 gzdirect(). 1411 */ 1412 1413 ZEXTERN int ZEXPORT gzclose OF((gzFile file)); 1414 /* 1415 Flushes all pending output if necessary, closes the compressed file and 1416 deallocates the (de)compression state. Note that once file is closed, you 1417 cannot call gzerror with file, since its structures have been deallocated. 1418 gzclose must not be called more than once on the same file, just as free 1419 must not be called more than once on the same allocation. 1420 1421 gzclose will return Z_STREAM_ERROR if file is not valid, Z_ERRNO on a 1422 file operation error, or Z_OK on success. 1423 */ 1424 1425 ZEXTERN int ZEXPORT gzclose_r OF((gzFile file)); 1426 ZEXTERN int ZEXPORT gzclose_w OF((gzFile file)); 1427 /* 1428 Same as gzclose(), but gzclose_r() is only for use when reading, and 1429 gzclose_w() is only for use when writing or appending. The advantage to 1430 using these instead of gzclose() is that they avoid linking in zlib 1431 compression or decompression code that is not used when only reading or only 1432 writing respectively. If gzclose() is used, then both compression and 1433 decompression code will be included the application when linking to a static 1434 zlib library. 1435 */ 1436 1437 ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum)); 1438 /* 1439 Returns the error message for the last error which occurred on the given 1440 compressed file. errnum is set to zlib error number. If an error occurred 1441 in the file system and not in the compression library, errnum is set to 1442 Z_ERRNO and the application may consult errno to get the exact error code. 1443 1444 The application must not modify the returned string. Future calls to 1445 this function may invalidate the previously returned string. If file is 1446 closed, then the string previously returned by gzerror will no longer be 1447 available. 1448 1449 gzerror() should be used to distinguish errors from end-of-file for those 1450 functions above that do not distinguish those cases in their return values. 1451 */ 1452 1453 ZEXTERN void ZEXPORT gzclearerr OF((gzFile file)); 1454 /* 1455 Clears the error and end-of-file flags for file. This is analogous to the 1456 clearerr() function in stdio. This is useful for continuing to read a gzip 1457 file that is being written concurrently. 1458 */ 1459 1460 1461 /* checksum functions */ 1462 1463 /* 1464 These functions are not related to compression but are exported 1465 anyway because they might be useful in applications using the compression 1466 library. 1467 */ 1468 1469 ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len)); 1470 /* 1471 Update a running Adler-32 checksum with the bytes buf[0..len-1] and 1472 return the updated checksum. If buf is Z_NULL, this function returns the 1473 required initial value for the checksum. 1474 1475 An Adler-32 checksum is almost as reliable as a CRC32 but can be computed 1476 much faster. 1477 1478 Usage example: 1479 1480 uLong adler = adler32(0L, Z_NULL, 0); 1481 1482 while (read_buffer(buffer, length) != EOF) { 1483 adler = adler32(adler, buffer, length); 1484 } 1485 if (adler != original_adler) error(); 1486 */ 1487 1488 /* 1489 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong adler1, uLong adler2, 1490 z_off_t len2)); 1491 1492 Combine two Adler-32 checksums into one. For two sequences of bytes, seq1 1493 and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for 1494 each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of 1495 seq1 and seq2 concatenated, requiring only adler1, adler2, and len2. 1496 */ 1497 1498 ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len)); 1499 /* 1500 Update a running CRC-32 with the bytes buf[0..len-1] and return the 1501 updated CRC-32. If buf is Z_NULL, this function returns the required 1502 initial value for the for the crc. Pre- and post-conditioning (one's 1503 complement) is performed within this function so it shouldn't be done by the 1504 application. 1505 1506 Usage example: 1507 1508 uLong crc = crc32(0L, Z_NULL, 0); 1509 1510 while (read_buffer(buffer, length) != EOF) { 1511 crc = crc32(crc, buffer, length); 1512 } 1513 if (crc != original_crc) error(); 1514 */ 1515 1516 /* 1517 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2)); 1518 1519 Combine two CRC-32 check values into one. For two sequences of bytes, 1520 seq1 and seq2 with lengths len1 and len2, CRC-32 check values were 1521 calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32 1522 check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and 1523 len2. 1524 */ 1525 1526 1527 /* various hacks, don't look :) */ 1528 1529 /* deflateInit and inflateInit are macros to allow checking the zlib version 1530 * and the compiler's view of z_stream: 1531 */ 1532 ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level, 1533 const char *version, int stream_size)); 1534 ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm, 1535 const char *version, int stream_size)); 1536 ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method, 1537 int windowBits, int memLevel, 1538 int strategy, const char *version, 1539 int stream_size)); 1540 ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits, 1541 const char *version, int stream_size)); 1542 ZEXTERN int ZEXPORT inflateBackInit_ OF((z_streamp strm, int windowBits, 1543 unsigned char FAR *window, 1544 const char *version, 1545 int stream_size)); 1546 #define deflateInit(strm, level) \ 1547 deflateInit_((strm), (level), ZLIB_VERSION, sizeof(z_stream)) 1548 #define inflateInit(strm) \ 1549 inflateInit_((strm), ZLIB_VERSION, sizeof(z_stream)) 1550 #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \ 1551 deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\ 1552 (strategy), ZLIB_VERSION, sizeof(z_stream)) 1553 #define inflateInit2(strm, windowBits) \ 1554 inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream)) 1555 #define inflateBackInit(strm, windowBits, window) \ 1556 inflateBackInit_((strm), (windowBits), (window), \ 1557 ZLIB_VERSION, sizeof(z_stream)) 1558 1559 /* provide 64-bit offset functions if _LARGEFILE64_SOURCE defined, and/or 1560 * change the regular functions to 64 bits if _FILE_OFFSET_BITS is 64 (if 1561 * both are true, the application gets the *64 functions, and the regular 1562 * functions are changed to 64 bits) -- in case these are set on systems 1563 * without large file support, _LFS64_LARGEFILE must also be true 1564 */ 1565 #if defined(_LARGEFILE64_SOURCE) && _LFS64_LARGEFILE-0 1566 ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *)); 1567 ZEXTERN z_off64_t ZEXPORT gzseek64 OF((gzFile, z_off64_t, int)); 1568 ZEXTERN z_off64_t ZEXPORT gztell64 OF((gzFile)); 1569 ZEXTERN z_off64_t ZEXPORT gzoffset64 OF((gzFile)); 1570 ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off64_t)); 1571 ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off64_t)); 1572 #endif 1573 1574 #if !defined(ZLIB_INTERNAL) && _FILE_OFFSET_BITS-0 == 64 && _LFS64_LARGEFILE-0 1575 # define gzopen gzopen64 1576 # define gzseek gzseek64 1577 # define gztell gztell64 1578 # define gzoffset gzoffset64 1579 # define adler32_combine adler32_combine64 1580 # define crc32_combine crc32_combine64 1581 # ifdef _LARGEFILE64_SOURCE 1582 ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *)); 1583 ZEXTERN z_off_t ZEXPORT gzseek64 OF((gzFile, z_off_t, int)); 1584 ZEXTERN z_off_t ZEXPORT gztell64 OF((gzFile)); 1585 ZEXTERN z_off_t ZEXPORT gzoffset64 OF((gzFile)); 1586 ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off_t)); 1587 ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off_t)); 1588 # endif 1589 #else 1590 ZEXTERN gzFile ZEXPORT gzopen OF((const char *, const char *)); 1591 ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile, z_off_t, int)); 1592 ZEXTERN z_off_t ZEXPORT gztell OF((gzFile)); 1593 ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile)); 1594 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t)); 1595 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t)); 1596 #endif 1597 1598 /* hack for buggy compilers */ 1599 #if !defined(ZUTIL_H) && !defined(NO_DUMMY_DECL) 1600 struct internal_state {int dummy;}; 1601 #endif 1602 1603 /* undocumented functions */ 1604 ZEXTERN const char * ZEXPORT zError OF((int)); 1605 ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp)); 1606 ZEXTERN const uLongf * ZEXPORT get_crc_table OF((void)); 1607 ZEXTERN int ZEXPORT inflateUndermine OF((z_streamp, int)); 1608 1609 #ifdef __cplusplus 1610 } 1611 #endif 1612 1613 #endif /* ZLIB_H */ 1614
