1 /* $NetBSD: zlib.h,v 1.3 1997/05/17 21:12:17 christos Exp $ */ 2 /* Id: zlib.h,v 1.5 1997/04/30 05:41:20 paulus Exp */ 3 4 /* 5 * This file is derived from zlib.h and zconf.h from the zlib-0.95 6 * distribution by Jean-loup Gailly and Mark Adler, with some additions 7 * by Paul Mackerras to aid in implementing Deflate compression and 8 * decompression for PPP packets. 9 */ 10 11 /* 12 * ==FILEVERSION 970421== 13 * 14 * This marker is used by the Linux installation script to determine 15 * whether an up-to-date version of this file is already installed. 16 */ 17 18 /* zlib.h -- interface of the 'zlib' general purpose compression library 19 version 0.95, Aug 16th, 1995. 20 21 Copyright (C) 1995 Jean-loup Gailly and Mark Adler 22 23 This software is provided 'as-is', without any express or implied 24 warranty. In no event will the authors be held liable for any damages 25 arising from the use of this software. 26 27 Permission is granted to anyone to use this software for any purpose, 28 including commercial applications, and to alter it and redistribute it 29 freely, subject to the following restrictions: 30 31 1. The origin of this software must not be misrepresented; you must not 32 claim that you wrote the original software. If you use this software 33 in a product, an acknowledgment in the product documentation would be 34 appreciated but is not required. 35 2. Altered source versions must be plainly marked as such, and must not be 36 misrepresented as being the original software. 37 3. This notice may not be removed or altered from any source distribution. 38 39 Jean-loup Gailly Mark Adler 40 gzip@prep.ai.mit.edu madler@alumni.caltech.edu 41 */ 42 43 #ifndef _ZLIB_H 44 #define _ZLIB_H 45 46 /* #include "zconf.h" */ /* included directly here */ 47 48 /* zconf.h -- configuration of the zlib compression library 49 * Copyright (C) 1995 Jean-loup Gailly. 50 * For conditions of distribution and use, see copyright notice in zlib.h 51 */ 52 53 /* From: zconf.h,v 1.12 1995/05/03 17:27:12 jloup Exp */ 54 55 /* 56 The library does not install any signal handler. It is recommended to 57 add at least a handler for SIGSEGV when decompressing; the library checks 58 the consistency of the input data whenever possible but may go nuts 59 for some forms of corrupted input. 60 */ 61 62 /* 63 * Compile with -DMAXSEG_64K if the alloc function cannot allocate more 64 * than 64k bytes at a time (needed on systems with 16-bit int). 65 * Compile with -DUNALIGNED_OK if it is OK to access shorts or ints 66 * at addresses which are not a multiple of their size. 67 * Under DOS, -DFAR=far or -DFAR=__far may be needed. 68 */ 69 70 #ifndef STDC 71 # if defined(MSDOS) || defined(__STDC__) || defined(__cplusplus) 72 # define STDC 73 # endif 74 #endif 75 76 #ifdef __MWERKS__ /* Metrowerks CodeWarrior declares fileno() in unix.h */ 77 # include <unix.h> 78 #endif 79 80 /* Maximum value for memLevel in deflateInit2 */ 81 #ifndef MAX_MEM_LEVEL 82 # ifdef MAXSEG_64K 83 # define MAX_MEM_LEVEL 8 84 # else 85 # define MAX_MEM_LEVEL 9 86 # endif 87 #endif 88 89 #ifndef FAR 90 # define FAR 91 #endif 92 93 /* Maximum value for windowBits in deflateInit2 and inflateInit2 */ 94 #ifndef MAX_WBITS 95 # define MAX_WBITS 15 /* 32K LZ77 window */ 96 #endif 97 98 /* The memory requirements for deflate are (in bytes): 99 1 << (windowBits+2) + 1 << (memLevel+9) 100 that is: 128K for windowBits=15 + 128K for memLevel = 8 (default values) 101 plus a few kilobytes for small objects. For example, if you want to reduce 102 the default memory requirements from 256K to 128K, compile with 103 make CFLAGS="-O -DMAX_WBITS=14 -DMAX_MEM_LEVEL=7" 104 Of course this will generally degrade compression (there's no free lunch). 105 106 The memory requirements for inflate are (in bytes) 1 << windowBits 107 that is, 32K for windowBits=15 (default value) plus a few kilobytes 108 for small objects. 109 */ 110 111 /* Type declarations */ 112 113 #ifndef OF /* function prototypes */ 114 # ifdef STDC 115 # define OF(args) args 116 # else 117 # define OF(args) () 118 # endif 119 #endif 120 121 typedef unsigned char Byte; /* 8 bits */ 122 typedef unsigned int uInt; /* 16 bits or more */ 123 typedef unsigned long uLong; /* 32 bits or more */ 124 125 typedef Byte FAR Bytef; 126 typedef char FAR charf; 127 typedef int FAR intf; 128 typedef uInt FAR uIntf; 129 typedef uLong FAR uLongf; 130 131 #ifdef STDC 132 typedef void FAR *voidpf; 133 typedef void *voidp; 134 #else 135 typedef Byte FAR *voidpf; 136 typedef Byte *voidp; 137 #endif 138 139 /* end of original zconf.h */ 140 141 #define ZLIB_VERSION "0.95P" 142 143 /* 144 The 'zlib' compression library provides in-memory compression and 145 decompression functions, including integrity checks of the uncompressed 146 data. This version of the library supports only one compression method 147 (deflation) but other algorithms may be added later and will have the same 148 stream interface. 149 150 For compression the application must provide the output buffer and 151 may optionally provide the input buffer for optimization. For decompression, 152 the application must provide the input buffer and may optionally provide 153 the output buffer for optimization. 154 155 Compression can be done in a single step if the buffers are large 156 enough (for example if an input file is mmap'ed), or can be done by 157 repeated calls of the compression function. In the latter case, the 158 application must provide more input and/or consume the output 159 (providing more output space) before each call. 160 */ 161 162 typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size)); 163 typedef void (*free_func) OF((voidpf opaque, voidpf address, uInt nbytes)); 164 165 struct internal_state; 166 167 typedef struct z_stream_s { 168 Bytef *next_in; /* next input byte */ 169 uInt avail_in; /* number of bytes available at next_in */ 170 uLong total_in; /* total nb of input bytes read so far */ 171 172 Bytef *next_out; /* next output byte should be put there */ 173 uInt avail_out; /* remaining free space at next_out */ 174 uLong total_out; /* total nb of bytes output so far */ 175 176 char *msg; /* last error message, NULL if no error */ 177 struct internal_state FAR *state; /* not visible by applications */ 178 179 alloc_func zalloc; /* used to allocate the internal state */ 180 alloc_func zalloc_init; /* used to allocate the internal state during initialization */ 181 free_func zfree; /* used to free the internal state */ 182 voidp opaque; /* private data object passed to zalloc and zfree */ 183 184 Byte data_type; /* best guess about the data type: ascii or binary */ 185 186 } z_stream; 187 188 /* 189 The application must update next_in and avail_in when avail_in has 190 dropped to zero. It must update next_out and avail_out when avail_out 191 has dropped to zero. The application must initialize zalloc, zfree and 192 opaque before calling the init function. All other fields are set by the 193 compression library and must not be updated by the application. 194 195 The opaque value provided by the application will be passed as the first 196 parameter for calls of zalloc and zfree. This can be useful for custom 197 memory management. The compression library attaches no meaning to the 198 opaque value. 199 200 zalloc must return Z_NULL if there is not enough memory for the object. 201 On 16-bit systems, the functions zalloc and zfree must be able to allocate 202 exactly 65536 bytes, but will not be required to allocate more than this 203 if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, 204 pointers returned by zalloc for objects of exactly 65536 bytes *must* 205 have their offset normalized to zero. The default allocation function 206 provided by this library ensures this (see zutil.c). To reduce memory 207 requirements and avoid any allocation of 64K objects, at the expense of 208 compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h). 209 210 The fields total_in and total_out can be used for statistics or 211 progress reports. After compression, total_in holds the total size of 212 the uncompressed data and may be saved for use in the decompressor 213 (particularly if the decompressor wants to decompress everything in 214 a single step). 215 */ 216 217 /* constants */ 218 219 #define Z_NO_FLUSH 0 220 #define Z_PARTIAL_FLUSH 1 221 #define Z_FULL_FLUSH 2 222 #define Z_SYNC_FLUSH 3 /* experimental: partial_flush + byte align */ 223 #define Z_FINISH 4 224 #define Z_PACKET_FLUSH 5 225 /* See deflate() below for the usage of these constants */ 226 227 #define Z_OK 0 228 #define Z_STREAM_END 1 229 #define Z_ERRNO (-1) 230 #define Z_STREAM_ERROR (-2) 231 #define Z_DATA_ERROR (-3) 232 #define Z_MEM_ERROR (-4) 233 #define Z_BUF_ERROR (-5) 234 /* error codes for the compression/decompression functions */ 235 236 #define Z_BEST_SPEED 1 237 #define Z_BEST_COMPRESSION 9 238 #define Z_DEFAULT_COMPRESSION (-1) 239 /* compression levels */ 240 241 #define Z_FILTERED 1 242 #define Z_HUFFMAN_ONLY 2 243 #define Z_DEFAULT_STRATEGY 0 244 245 #define Z_BINARY 0 246 #define Z_ASCII 1 247 #define Z_UNKNOWN 2 248 /* Used to set the data_type field */ 249 250 #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */ 251 252 extern char *zlib_version; 253 /* The application can compare zlib_version and ZLIB_VERSION for consistency. 254 If the first character differs, the library code actually used is 255 not compatible with the zlib.h header file used by the application. 256 */ 257 258 /* basic functions */ 259 260 extern int deflateInit OF((z_stream *strm, int level)); 261 /* 262 Initializes the internal stream state for compression. The fields 263 zalloc, zfree and opaque must be initialized before by the caller. 264 If zalloc and zfree are set to Z_NULL, deflateInit updates them to 265 use default allocation functions. 266 267 The compression level must be Z_DEFAULT_COMPRESSION, or between 1 and 9: 268 1 gives best speed, 9 gives best compression. Z_DEFAULT_COMPRESSION requests 269 a default compromise between speed and compression (currently equivalent 270 to level 6). 271 272 deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not 273 enough memory, Z_STREAM_ERROR if level is not a valid compression level. 274 msg is set to null if there is no error message. deflateInit does not 275 perform any compression: this will be done by deflate(). 276 */ 277 278 279 extern int deflate OF((z_stream *strm, int flush)); 280 /* 281 Performs one or both of the following actions: 282 283 - Compress more input starting at next_in and update next_in and avail_in 284 accordingly. If not all input can be processed (because there is not 285 enough room in the output buffer), next_in and avail_in are updated and 286 processing will resume at this point for the next call of deflate(). 287 288 - Provide more output starting at next_out and update next_out and avail_out 289 accordingly. This action is forced if the parameter flush is non zero. 290 Forcing flush frequently degrades the compression ratio, so this parameter 291 should be set only when necessary (in interactive applications). 292 Some output may be provided even if flush is not set. 293 294 Before the call of deflate(), the application should ensure that at least 295 one of the actions is possible, by providing more input and/or consuming 296 more output, and updating avail_in or avail_out accordingly; avail_out 297 should never be zero before the call. The application can consume the 298 compressed output when it wants, for example when the output buffer is full 299 (avail_out == 0), or after each call of deflate(). 300 301 If the parameter flush is set to Z_PARTIAL_FLUSH, the current compression 302 block is terminated and flushed to the output buffer so that the 303 decompressor can get all input data available so far. For method 9, a future 304 variant on method 8, the current block will be flushed but not terminated. 305 If flush is set to Z_FULL_FLUSH, the compression block is terminated, a 306 special marker is output and the compression dictionary is discarded; this 307 is useful to allow the decompressor to synchronize if one compressed block 308 has been damaged (see inflateSync below). Flushing degrades compression and 309 so should be used only when necessary. Using Z_FULL_FLUSH too often can 310 seriously degrade the compression. If deflate returns with avail_out == 0, 311 this function must be called again with the same value of the flush 312 parameter and more output space (updated avail_out), until the flush is 313 complete (deflate returns with non-zero avail_out). 314 315 If the parameter flush is set to Z_PACKET_FLUSH, the compression 316 block is terminated, and a zero-length stored block is output, 317 omitting the length bytes (the effect of this is that the 3-bit type 318 code 000 for a stored block is output, and the output is then 319 byte-aligned). This is designed for use at the end of a PPP packet. 320 In addition, if the current compression block contains all the data 321 since the last Z_PACKET_FLUSH, it is never output as a stored block. 322 If the current compression block output as a static or dynamic block 323 would not be at least `minCompression' bytes smaller than the 324 original data, then nothing is output for that block. (The type 325 code for the zero-length stored block is still output, resulting in 326 a single zero byte being output for the whole packet.) 327 `MinCompression' is a parameter to deflateInit2, or 0 if deflateInit 328 is used. 329 330 If the parameter flush is set to Z_FINISH, all pending input is processed, 331 all pending output is flushed and deflate returns with Z_STREAM_END if there 332 was enough output space; if deflate returns with Z_OK, this function must be 333 called again with Z_FINISH and more output space (updated avail_out) but no 334 more input data, until it returns with Z_STREAM_END or an error. After 335 deflate has returned Z_STREAM_END, the only possible operations on the 336 stream are deflateReset or deflateEnd. 337 338 Z_FINISH can be used immediately after deflateInit if all the compression 339 is to be done in a single step. In this case, avail_out must be at least 340 0.1% larger than avail_in plus 12 bytes. If deflate does not return 341 Z_STREAM_END, then it must be called again as described above. 342 343 deflate() may update data_type if it can make a good guess about 344 the input data type (Z_ASCII or Z_BINARY). In doubt, the data is considered 345 binary. This field is only for information purposes and does not affect 346 the compression algorithm in any manner. 347 348 deflate() returns Z_OK if some progress has been made (more input 349 processed or more output produced), Z_STREAM_END if all input has been 350 consumed and all output has been produced (only when flush is set to 351 Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example 352 if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible. 353 */ 354 355 356 extern int deflateEnd OF((z_stream *strm)); 357 /* 358 All dynamically allocated data structures for this stream are freed. 359 This function discards any unprocessed input and does not flush any 360 pending output. 361 362 deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the 363 stream state was inconsistent. In the error case, msg may be set 364 but then points to a static string (which must not be deallocated). 365 */ 366 367 368 extern int inflateInit OF((z_stream *strm)); 369 /* 370 Initializes the internal stream state for decompression. The fields 371 zalloc and zfree must be initialized before by the caller. If zalloc and 372 zfree are set to Z_NULL, inflateInit updates them to use default allocation 373 functions. 374 375 inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not 376 enough memory. msg is set to null if there is no error message. 377 inflateInit does not perform any decompression: this will be done by 378 inflate(). 379 */ 380 381 382 #if defined(__FreeBSD__) && (defined(KERNEL) || defined(_KERNEL)) 383 #define inflate inflate_ppp /* FreeBSD already has an inflate :-( */ 384 #endif 385 386 extern int inflate OF((z_stream *strm, int flush)); 387 /* 388 Performs one or both of the following actions: 389 390 - Decompress more input starting at next_in and update next_in and avail_in 391 accordingly. If not all input can be processed (because there is not 392 enough room in the output buffer), next_in is updated and processing 393 will resume at this point for the next call of inflate(). 394 395 - Provide more output starting at next_out and update next_out and avail_out 396 accordingly. inflate() always provides as much output as possible 397 (until there is no more input data or no more space in the output buffer). 398 399 Before the call of inflate(), the application should ensure that at least 400 one of the actions is possible, by providing more input and/or consuming 401 more output, and updating the next_* and avail_* values accordingly. 402 The application can consume the uncompressed output when it wants, for 403 example when the output buffer is full (avail_out == 0), or after each 404 call of inflate(). 405 406 If the parameter flush is set to Z_PARTIAL_FLUSH or Z_PACKET_FLUSH, 407 inflate flushes as much output as possible to the output buffer. The 408 flushing behavior of inflate is not specified for values of the flush 409 parameter other than Z_PARTIAL_FLUSH, Z_PACKET_FLUSH or Z_FINISH, but the 410 current implementation actually flushes as much output as possible 411 anyway. For Z_PACKET_FLUSH, inflate checks that once all the input data 412 has been consumed, it is expecting to see the length field of a stored 413 block; if not, it returns Z_DATA_ERROR. 414 415 inflate() should normally be called until it returns Z_STREAM_END or an 416 error. However if all decompression is to be performed in a single step 417 (a single call of inflate), the parameter flush should be set to 418 Z_FINISH. In this case all pending input is processed and all pending 419 output is flushed; avail_out must be large enough to hold all the 420 uncompressed data. (The size of the uncompressed data may have been saved 421 by the compressor for this purpose.) The next operation on this stream must 422 be inflateEnd to deallocate the decompression state. The use of Z_FINISH 423 is never required, but can be used to inform inflate that a faster routine 424 may be used for the single inflate() call. 425 426 inflate() returns Z_OK if some progress has been made (more input 427 processed or more output produced), Z_STREAM_END if the end of the 428 compressed data has been reached and all uncompressed output has been 429 produced, Z_DATA_ERROR if the input data was corrupted, Z_STREAM_ERROR if 430 the stream structure was inconsistent (for example if next_in or next_out 431 was NULL), Z_MEM_ERROR if there was not enough memory, Z_BUF_ERROR if no 432 progress is possible or if there was not enough room in the output buffer 433 when Z_FINISH is used. In the Z_DATA_ERROR case, the application may then 434 call inflateSync to look for a good compression block. */ 435 436 437 extern int inflateEnd OF((z_stream *strm)); 438 /* 439 All dynamically allocated data structures for this stream are freed. 440 This function discards any unprocessed input and does not flush any 441 pending output. 442 443 inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state 444 was inconsistent. In the error case, msg may be set but then points to a 445 static string (which must not be deallocated). 446 */ 447 448 /* advanced functions */ 449 450 /* 451 The following functions are needed only in some special applications. 452 */ 453 454 extern int deflateInit2 OF((z_stream *strm, 455 int level, 456 int method, 457 int windowBits, 458 int memLevel, 459 int strategy, 460 int minCompression)); 461 /* 462 This is another version of deflateInit with more compression options. The 463 fields next_in, zalloc and zfree must be initialized before by the caller. 464 465 The method parameter is the compression method. It must be 8 in this 466 version of the library. (Method 9 will allow a 64K history buffer and 467 partial block flushes.) 468 469 The windowBits parameter is the base two logarithm of the window size 470 (the size of the history buffer). It should be in the range 8..15 for this 471 version of the library (the value 16 will be allowed for method 9). Larger 472 values of this parameter result in better compression at the expense of 473 memory usage. The default value is 15 if deflateInit is used instead. 474 475 The memLevel parameter specifies how much memory should be allocated 476 for the internal compression state. memLevel=1 uses minimum memory but 477 is slow and reduces compression ratio; memLevel=9 uses maximum memory 478 for optimal speed. The default value is 8. See zconf.h for total memory 479 usage as a function of windowBits and memLevel. 480 481 The strategy parameter is used to tune the compression algorithm. Use 482 the value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data 483 produced by a filter (or predictor), or Z_HUFFMAN_ONLY to force Huffman 484 encoding only (no string match). Filtered data consists mostly of small 485 values with a somewhat random distribution. In this case, the 486 compression algorithm is tuned to compress them better. The strategy 487 parameter only affects the compression ratio but not the correctness of 488 the compressed output even if it is not set appropriately. 489 490 The minCompression parameter specifies the minimum reduction in size 491 required for a compressed block to be output when Z_PACKET_FLUSH is 492 used (see the description of deflate above). 493 494 If next_in is not null, the library will use this buffer to hold also 495 some history information; the buffer must either hold the entire input 496 data, or have at least 1<<(windowBits+1) bytes and be writable. If next_in 497 is null, the library will allocate its own history buffer (and leave next_in 498 null). next_out need not be provided here but must be provided by the 499 application for the next call of deflate(). 500 501 If the history buffer is provided by the application, next_in must 502 must never be changed by the application since the compressor maintains 503 information inside this buffer from call to call; the application 504 must provide more input only by increasing avail_in. next_in is always 505 reset by the library in this case. 506 507 deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was 508 not enough memory, Z_STREAM_ERROR if a parameter is invalid (such as 509 an invalid method). msg is set to null if there is no error message. 510 deflateInit2 does not perform any compression: this will be done by 511 deflate(). 512 */ 513 514 extern int deflateCopy OF((z_stream *dest, 515 z_stream *source)); 516 /* 517 Sets the destination stream as a complete copy of the source stream. If 518 the source stream is using an application-supplied history buffer, a new 519 buffer is allocated for the destination stream. The compressed output 520 buffer is always application-supplied. It's the responsibility of the 521 application to provide the correct values of next_out and avail_out for the 522 next call of deflate. 523 524 This function is useful when several compression strategies will be 525 tried, for example when there are several ways of pre-processing the input 526 data with a filter. The streams that will be discarded should then be freed 527 by calling deflateEnd. Note that deflateCopy duplicates the internal 528 compression state which can be quite large, so this strategy is slow and 529 can consume lots of memory. 530 531 deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not 532 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent 533 (such as zalloc being NULL). msg is left unchanged in both source and 534 destination. 535 */ 536 537 extern int deflateReset OF((z_stream *strm)); 538 /* 539 This function is equivalent to deflateEnd followed by deflateInit, 540 but does not free and reallocate all the internal compression state. 541 The stream will keep the same compression level and any other attributes 542 that may have been set by deflateInit2. 543 544 deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source 545 stream state was inconsistent (such as zalloc or state being NULL). 546 */ 547 548 extern int inflateInit2 OF((z_stream *strm, 549 int windowBits)); 550 /* 551 This is another version of inflateInit with more compression options. The 552 fields next_out, zalloc and zfree must be initialized before by the caller. 553 554 The windowBits parameter is the base two logarithm of the maximum window 555 size (the size of the history buffer). It should be in the range 8..15 for 556 this version of the library (the value 16 will be allowed soon). The 557 default value is 15 if inflateInit is used instead. If a compressed stream 558 with a larger window size is given as input, inflate() will return with 559 the error code Z_DATA_ERROR instead of trying to allocate a larger window. 560 561 If next_out is not null, the library will use this buffer for the history 562 buffer; the buffer must either be large enough to hold the entire output 563 data, or have at least 1<<windowBits bytes. If next_out is null, the 564 library will allocate its own buffer (and leave next_out null). next_in 565 need not be provided here but must be provided by the application for the 566 next call of inflate(). 567 568 If the history buffer is provided by the application, next_out must 569 never be changed by the application since the decompressor maintains 570 history information inside this buffer from call to call; the application 571 can only reset next_out to the beginning of the history buffer when 572 avail_out is zero and all output has been consumed. 573 574 inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was 575 not enough memory, Z_STREAM_ERROR if a parameter is invalid (such as 576 windowBits < 8). msg is set to null if there is no error message. 577 inflateInit2 does not perform any decompression: this will be done by 578 inflate(). 579 */ 580 581 extern int inflateSync OF((z_stream *strm)); 582 /* 583 Skips invalid compressed data until the special marker (see deflate() 584 above) can be found, or until all available input is skipped. No output 585 is provided. 586 587 inflateSync returns Z_OK if the special marker has been found, Z_BUF_ERROR 588 if no more input was provided, Z_DATA_ERROR if no marker has been found, 589 or Z_STREAM_ERROR if the stream structure was inconsistent. In the success 590 case, the application may save the current current value of total_in which 591 indicates where valid compressed data was found. In the error case, the 592 application may repeatedly call inflateSync, providing more input each time, 593 until success or end of the input data. 594 */ 595 596 extern int inflateReset OF((z_stream *strm)); 597 /* 598 This function is equivalent to inflateEnd followed by inflateInit, 599 but does not free and reallocate all the internal decompression state. 600 The stream will keep attributes that may have been set by inflateInit2. 601 602 inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source 603 stream state was inconsistent (such as zalloc or state being NULL). 604 */ 605 606 extern int inflateIncomp OF((z_stream *strm)); 607 /* 608 This function adds the data at next_in (avail_in bytes) to the output 609 history without performing any output. There must be no pending output, 610 and the decompressor must be expecting to see the start of a block. 611 Calling this function is equivalent to decompressing a stored block 612 containing the data at next_in (except that the data is not output). 613 */ 614 615 /* checksum functions */ 616 617 /* 618 This function is not related to compression but is exported 619 anyway because it might be useful in applications using the 620 compression library. 621 */ 622 623 extern uLong adler32 OF((uLong adler, Bytef *buf, uInt len)); 624 625 /* 626 Update a running Adler-32 checksum with the bytes buf[0..len-1] and 627 return the updated checksum. If buf is NULL, this function returns 628 the required initial value for the checksum. 629 An Adler-32 checksum is almost as reliable as a CRC32 but can be computed 630 much faster. Usage example: 631 632 uLong adler = adler32(0L, Z_NULL, 0); 633 634 while (read_buffer(buffer, length) != EOF) { 635 adler = adler32(adler, buffer, length); 636 } 637 if (adler != original_adler) error(); 638 */ 639 640 #ifndef _Z_UTIL_H 641 struct internal_state {int dummy;}; /* hack for buggy compilers */ 642 #endif 643 644 #endif /* _ZLIB_H */ 645