1/* zlib.h -- interface of the 'zlib' general purpose compression library 2 3 Copyright (C) 1995-2005 Jean-loup Gailly and Mark Adler 4 5 This software is provided 'as-is', without any express or implied 6 warranty. In no event will the authors be held liable for any damages 7 arising from the use of this software. 8 9 Permission is granted to anyone to use this software for any purpose, 10 including commercial applications, and to alter it and redistribute it 11 freely, subject to the following restrictions: 12 13 1. The origin of this software must not be misrepresented; you must not 14 claim that you wrote the original software. If you use this software 15 in a product, an acknowledgment in the product documentation would be 16 appreciated but is not required. 17 2. Altered source versions must be plainly marked as such, and must not be 18 misrepresented as being the original software. 19 3. This notice may not be removed or altered from any source distribution. 20 21 Jean-loup Gailly Mark Adler 22 jloup@gzip.org madler@alumni.caltech.edu 23 24 25 The data format used by the zlib library is described by RFCs (Request for 26 Comments) 1950 to 1952 in the files https://www.ietf.org/rfc/rfc1950.txt 27 (zlib format), rfc1951.txt (deflate format) and rfc1952.txt (gzip format). 28*/ 29 30#ifndef _ZLIB_H 31#define _ZLIB_H 32 33#include <linux/zconf.h> 34 35/* zlib deflate based on ZLIB_VERSION "1.1.3" */ 36/* zlib inflate based on ZLIB_VERSION "1.2.3" */ 37 38/* 39 This is a modified version of zlib for use inside the Linux kernel. 40 The main changes are to perform all memory allocation in advance. 41 42 Inflation Changes: 43 * Z_PACKET_FLUSH is added and used by ppp_deflate. Before returning 44 this checks there is no more input data available and the next data 45 is a STORED block. It also resets the mode to be read for the next 46 data, all as per PPP requirements. 47 * Addition of zlib_inflateIncomp which copies incompressible data into 48 the history window and adjusts the accoutning without calling 49 zlib_inflate itself to inflate the data. 50*/ 51 52/* 53 The 'zlib' compression library provides in-memory compression and 54 decompression functions, including integrity checks of the uncompressed 55 data. This version of the library supports only one compression method 56 (deflation) but other algorithms will be added later and will have the same 57 stream interface. 58 59 Compression can be done in a single step if the buffers are large 60 enough (for example if an input file is mmap'ed), or can be done by 61 repeated calls of the compression function. In the latter case, the 62 application must provide more input and/or consume the output 63 (providing more output space) before each call. 64 65 The compressed data format used by default by the in-memory functions is 66 the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped 67 around a deflate stream, which is itself documented in RFC 1951. 68 69 The library also supports reading and writing files in gzip (.gz) format 70 with an interface similar to that of stdio. 71 72 The zlib format was designed to be compact and fast for use in memory 73 and on communications channels. The gzip format was designed for single- 74 file compression on file systems, has a larger header than zlib to maintain 75 directory information, and uses a different, slower check method than zlib. 76 77 The library does not install any signal handler. The decoder checks 78 the consistency of the compressed data, so the library should never 79 crash even in case of corrupted input. 80*/ 81 82struct internal_state; 83 84typedef struct z_stream_s { 85 const Byte *next_in; /* next input byte */ 86 uLong avail_in; /* number of bytes available at next_in */ 87 uLong total_in; /* total nb of input bytes read so far */ 88 89 Byte *next_out; /* next output byte should be put there */ 90 uLong avail_out; /* remaining free space at next_out */ 91 uLong total_out; /* total nb of bytes output so far */ 92 93 char *msg; /* last error message, NULL if no error */ 94 struct internal_state *state; /* not visible by applications */ 95 96 void *workspace; /* memory allocated for this stream */ 97 98 int data_type; /* best guess about the data type: ascii or binary */ 99 uLong adler; /* adler32 value of the uncompressed data */ 100 uLong reserved; /* reserved for future use */ 101} z_stream; 102 103typedef z_stream *z_streamp; 104 105/* 106 The application must update next_in and avail_in when avail_in has 107 dropped to zero. It must update next_out and avail_out when avail_out 108 has dropped to zero. The application must initialize zalloc, zfree and 109 opaque before calling the init function. All other fields are set by the 110 compression library and must not be updated by the application. 111 112 The opaque value provided by the application will be passed as the first 113 parameter for calls of zalloc and zfree. This can be useful for custom 114 memory management. The compression library attaches no meaning to the 115 opaque value. 116 117 zalloc must return NULL if there is not enough memory for the object. 118 If zlib is used in a multi-threaded application, zalloc and zfree must be 119 thread safe. 120 121 On 16-bit systems, the functions zalloc and zfree must be able to allocate 122 exactly 65536 bytes, but will not be required to allocate more than this 123 if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS, 124 pointers returned by zalloc for objects of exactly 65536 bytes *must* 125 have their offset normalized to zero. The default allocation function 126 provided by this library ensures this (see zutil.c). To reduce memory 127 requirements and avoid any allocation of 64K objects, at the expense of 128 compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h). 129 130 The fields total_in and total_out can be used for statistics or 131 progress reports. After compression, total_in holds the total size of 132 the uncompressed data and may be saved for use in the decompressor 133 (particularly if the decompressor wants to decompress everything in 134 a single step). 135*/ 136 137 /* constants */ 138 139#define Z_NO_FLUSH 0 140#define Z_PARTIAL_FLUSH 1 /* will be removed, use Z_SYNC_FLUSH instead */ 141#define Z_PACKET_FLUSH 2 142#define Z_SYNC_FLUSH 3 143#define Z_FULL_FLUSH 4 144#define Z_FINISH 5 145#define Z_BLOCK 6 /* Only for inflate at present */ 146/* Allowed flush values; see deflate() and inflate() below for details */ 147 148#define Z_OK 0 149#define Z_STREAM_END 1 150#define Z_NEED_DICT 2 151#define Z_ERRNO (-1) 152#define Z_STREAM_ERROR (-2) 153#define Z_DATA_ERROR (-3) 154#define Z_MEM_ERROR (-4) 155#define Z_BUF_ERROR (-5) 156#define Z_VERSION_ERROR (-6) 157/* Return codes for the compression/decompression functions. Negative 158 * values are errors, positive values are used for special but normal events. 159 */ 160 161#define Z_NO_COMPRESSION 0 162#define Z_BEST_SPEED 1 163#define Z_BEST_COMPRESSION 9 164#define Z_DEFAULT_COMPRESSION (-1) 165/* compression levels */ 166 167#define Z_FILTERED 1 168#define Z_HUFFMAN_ONLY 2 169#define Z_DEFAULT_STRATEGY 0 170/* compression strategy; see deflateInit2() below for details */ 171 172#define Z_BINARY 0 173#define Z_ASCII 1 174#define Z_UNKNOWN 2 175/* Possible values of the data_type field */ 176 177#define Z_DEFLATED 8 178/* The deflate compression method (the only one supported in this version) */ 179 180 /* basic functions */ 181 182extern int zlib_deflate_workspacesize (int windowBits, int memLevel); 183/* 184 Returns the number of bytes that needs to be allocated for a per- 185 stream workspace with the specified parameters. A pointer to this 186 number of bytes should be returned in stream->workspace before 187 you call zlib_deflateInit() or zlib_deflateInit2(). If you call 188 zlib_deflateInit(), specify windowBits = MAX_WBITS and memLevel = 189 MAX_MEM_LEVEL here. If you call zlib_deflateInit2(), the windowBits 190 and memLevel parameters passed to zlib_deflateInit2() must not 191 exceed those passed here. 192*/ 193 194extern int zlib_deflate_dfltcc_enabled (void); 195/* 196 Returns 1 if Deflate-Conversion facility is installed and enabled, 197 otherwise 0. 198*/ 199 200/* 201extern int deflateInit (z_streamp strm, int level); 202 203 Initializes the internal stream state for compression. The fields 204 zalloc, zfree and opaque must be initialized before by the caller. 205 If zalloc and zfree are set to NULL, deflateInit updates them to 206 use default allocation functions. 207 208 The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9: 209 1 gives best speed, 9 gives best compression, 0 gives no compression at 210 all (the input data is simply copied a block at a time). 211 Z_DEFAULT_COMPRESSION requests a default compromise between speed and 212 compression (currently equivalent to level 6). 213 214 deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not 215 enough memory, Z_STREAM_ERROR if level is not a valid compression level, 216 Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible 217 with the version assumed by the caller (ZLIB_VERSION). 218 msg is set to null if there is no error message. deflateInit does not 219 perform any compression: this will be done by deflate(). 220*/ 221 222 223extern int zlib_deflate (z_streamp strm, int flush); 224/* 225 deflate compresses as much data as possible, and stops when the input 226 buffer becomes empty or the output buffer becomes full. It may introduce some 227 output latency (reading input without producing any output) except when 228 forced to flush. 229 230 The detailed semantics are as follows. deflate performs one or both of the 231 following actions: 232 233 - Compress more input starting at next_in and update next_in and avail_in 234 accordingly. If not all input can be processed (because there is not 235 enough room in the output buffer), next_in and avail_in are updated and 236 processing will resume at this point for the next call of deflate(). 237 238 - Provide more output starting at next_out and update next_out and avail_out 239 accordingly. This action is forced if the parameter flush is non zero. 240 Forcing flush frequently degrades the compression ratio, so this parameter 241 should be set only when necessary (in interactive applications). 242 Some output may be provided even if flush is not set. 243 244 Before the call of deflate(), the application should ensure that at least 245 one of the actions is possible, by providing more input and/or consuming 246 more output, and updating avail_in or avail_out accordingly; avail_out 247 should never be zero before the call. The application can consume the 248 compressed output when it wants, for example when the output buffer is full 249 (avail_out == 0), or after each call of deflate(). If deflate returns Z_OK 250 and with zero avail_out, it must be called again after making room in the 251 output buffer because there might be more output pending. 252 253 If the parameter flush is set to Z_SYNC_FLUSH, all pending output is 254 flushed to the output buffer and the output is aligned on a byte boundary, so 255 that the decompressor can get all input data available so far. (In particular 256 avail_in is zero after the call if enough output space has been provided 257 before the call.) Flushing may degrade compression for some compression 258 algorithms and so it should be used only when necessary. 259 260 If flush is set to Z_FULL_FLUSH, all output is flushed as with 261 Z_SYNC_FLUSH, and the compression state is reset so that decompression can 262 restart from this point if previous compressed data has been damaged or if 263 random access is desired. Using Z_FULL_FLUSH too often can seriously degrade 264 the compression. 265 266 If deflate returns with avail_out == 0, this function must be called again 267 with the same value of the flush parameter and more output space (updated 268 avail_out), until the flush is complete (deflate returns with non-zero 269 avail_out). 270 271 If the parameter flush is set to Z_FINISH, pending input is processed, 272 pending output is flushed and deflate returns with Z_STREAM_END if there 273 was enough output space; if deflate returns with Z_OK, this function must be 274 called again with Z_FINISH and more output space (updated avail_out) but no 275 more input data, until it returns with Z_STREAM_END or an error. After 276 deflate has returned Z_STREAM_END, the only possible operations on the 277 stream are deflateReset or deflateEnd. 278 279 Z_FINISH can be used immediately after deflateInit if all the compression 280 is to be done in a single step. In this case, avail_out must be at least 281 0.1% larger than avail_in plus 12 bytes. If deflate does not return 282 Z_STREAM_END, then it must be called again as described above. 283 284 deflate() sets strm->adler to the adler32 checksum of all input read 285 so far (that is, total_in bytes). 286 287 deflate() may update data_type if it can make a good guess about 288 the input data type (Z_ASCII or Z_BINARY). In doubt, the data is considered 289 binary. This field is only for information purposes and does not affect 290 the compression algorithm in any manner. 291 292 deflate() returns Z_OK if some progress has been made (more input 293 processed or more output produced), Z_STREAM_END if all input has been 294 consumed and all output has been produced (only when flush is set to 295 Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example 296 if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible 297 (for example avail_in or avail_out was zero). 298*/ 299 300 301extern int zlib_deflateEnd (z_streamp strm); 302/* 303 All dynamically allocated data structures for this stream are freed. 304 This function discards any unprocessed input and does not flush any 305 pending output. 306 307 deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the 308 stream state was inconsistent, Z_DATA_ERROR if the stream was freed 309 prematurely (some input or output was discarded). In the error case, 310 msg may be set but then points to a static string (which must not be 311 deallocated). 312*/ 313 314 315extern int zlib_inflate_workspacesize (void); 316/* 317 Returns the number of bytes that needs to be allocated for a per- 318 stream workspace. A pointer to this number of bytes should be 319 returned in stream->workspace before calling zlib_inflateInit(). 320*/ 321 322/* 323extern int zlib_inflateInit (z_streamp strm); 324 325 Initializes the internal stream state for decompression. The fields 326 next_in, avail_in, and workspace must be initialized before by 327 the caller. If next_in is not NULL and avail_in is large enough (the exact 328 value depends on the compression method), inflateInit determines the 329 compression method from the zlib header and allocates all data structures 330 accordingly; otherwise the allocation will be deferred to the first call of 331 inflate. If zalloc and zfree are set to NULL, inflateInit updates them to 332 use default allocation functions. 333 334 inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough 335 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the 336 version assumed by the caller. msg is set to null if there is no error 337 message. inflateInit does not perform any decompression apart from reading 338 the zlib header if present: this will be done by inflate(). (So next_in and 339 avail_in may be modified, but next_out and avail_out are unchanged.) 340*/ 341 342 343extern int zlib_inflate (z_streamp strm, int flush); 344/* 345 inflate decompresses as much data as possible, and stops when the input 346 buffer becomes empty or the output buffer becomes full. It may introduce 347 some output latency (reading input without producing any output) except when 348 forced to flush. 349 350 The detailed semantics are as follows. inflate performs one or both of the 351 following actions: 352 353 - Decompress more input starting at next_in and update next_in and avail_in 354 accordingly. If not all input can be processed (because there is not 355 enough room in the output buffer), next_in is updated and processing 356 will resume at this point for the next call of inflate(). 357 358 - Provide more output starting at next_out and update next_out and avail_out 359 accordingly. inflate() provides as much output as possible, until there 360 is no more input data or no more space in the output buffer (see below 361 about the flush parameter). 362 363 Before the call of inflate(), the application should ensure that at least 364 one of the actions is possible, by providing more input and/or consuming 365 more output, and updating the next_* and avail_* values accordingly. 366 The application can consume the uncompressed output when it wants, for 367 example when the output buffer is full (avail_out == 0), or after each 368 call of inflate(). If inflate returns Z_OK and with zero avail_out, it 369 must be called again after making room in the output buffer because there 370 might be more output pending. 371 372 The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, 373 Z_FINISH, or Z_BLOCK. Z_SYNC_FLUSH requests that inflate() flush as much 374 output as possible to the output buffer. Z_BLOCK requests that inflate() stop 375 if and when it gets to the next deflate block boundary. When decoding the 376 zlib or gzip format, this will cause inflate() to return immediately after 377 the header and before the first block. When doing a raw inflate, inflate() 378 will go ahead and process the first block, and will return when it gets to 379 the end of that block, or when it runs out of data. 380 381 The Z_BLOCK option assists in appending to or combining deflate streams. 382 Also to assist in this, on return inflate() will set strm->data_type to the 383 number of unused bits in the last byte taken from strm->next_in, plus 64 384 if inflate() is currently decoding the last block in the deflate stream, 385 plus 128 if inflate() returned immediately after decoding an end-of-block 386 code or decoding the complete header up to just before the first byte of the 387 deflate stream. The end-of-block will not be indicated until all of the 388 uncompressed data from that block has been written to strm->next_out. The 389 number of unused bits may in general be greater than seven, except when 390 bit 7 of data_type is set, in which case the number of unused bits will be 391 less than eight. 392 393 inflate() should normally be called until it returns Z_STREAM_END or an 394 error. However if all decompression is to be performed in a single step 395 (a single call of inflate), the parameter flush should be set to 396 Z_FINISH. In this case all pending input is processed and all pending 397 output is flushed; avail_out must be large enough to hold all the 398 uncompressed data. (The size of the uncompressed data may have been saved 399 by the compressor for this purpose.) The next operation on this stream must 400 be inflateEnd to deallocate the decompression state. The use of Z_FINISH 401 is never required, but can be used to inform inflate that a faster approach 402 may be used for the single inflate() call. 403 404 In this implementation, inflate() always flushes as much output as 405 possible to the output buffer, and always uses the faster approach on the 406 first call. So the only effect of the flush parameter in this implementation 407 is on the return value of inflate(), as noted below, or when it returns early 408 because Z_BLOCK is used. 409 410 If a preset dictionary is needed after this call (see inflateSetDictionary 411 below), inflate sets strm->adler to the adler32 checksum of the dictionary 412 chosen by the compressor and returns Z_NEED_DICT; otherwise it sets 413 strm->adler to the adler32 checksum of all output produced so far (that is, 414 total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described 415 below. At the end of the stream, inflate() checks that its computed adler32 416 checksum is equal to that saved by the compressor and returns Z_STREAM_END 417 only if the checksum is correct. 418 419 inflate() will decompress and check either zlib-wrapped or gzip-wrapped 420 deflate data. The header type is detected automatically. Any information 421 contained in the gzip header is not retained, so applications that need that 422 information should instead use raw inflate, see inflateInit2() below, or 423 inflateBack() and perform their own processing of the gzip header and 424 trailer. 425 426 inflate() returns Z_OK if some progress has been made (more input processed 427 or more output produced), Z_STREAM_END if the end of the compressed data has 428 been reached and all uncompressed output has been produced, Z_NEED_DICT if a 429 preset dictionary is needed at this point, Z_DATA_ERROR if the input data was 430 corrupted (input stream not conforming to the zlib format or incorrect check 431 value), Z_STREAM_ERROR if the stream structure was inconsistent (for example 432 if next_in or next_out was NULL), Z_MEM_ERROR if there was not enough memory, 433 Z_BUF_ERROR if no progress is possible or if there was not enough room in the 434 output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and 435 inflate() can be called again with more input and more output space to 436 continue decompressing. If Z_DATA_ERROR is returned, the application may then 437 call inflateSync() to look for a good compression block if a partial recovery 438 of the data is desired. 439*/ 440 441 442extern int zlib_inflateEnd (z_streamp strm); 443/* 444 All dynamically allocated data structures for this stream are freed. 445 This function discards any unprocessed input and does not flush any 446 pending output. 447 448 inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state 449 was inconsistent. In the error case, msg may be set but then points to a 450 static string (which must not be deallocated). 451*/ 452 453 /* Advanced functions */ 454 455/* 456 The following functions are needed only in some special applications. 457*/ 458 459/* 460extern int deflateInit2 (z_streamp strm, 461 int level, 462 int method, 463 int windowBits, 464 int memLevel, 465 int strategy); 466 467 This is another version of deflateInit with more compression options. The 468 fields next_in, zalloc, zfree and opaque must be initialized before by 469 the caller. 470 471 The method parameter is the compression method. It must be Z_DEFLATED in 472 this version of the library. 473 474 The windowBits parameter is the base two logarithm of the window size 475 (the size of the history buffer). It should be in the range 8..15 for this 476 version of the library. Larger values of this parameter result in better 477 compression at the expense of memory usage. The default value is 15 if 478 deflateInit is used instead. 479 480 The memLevel parameter specifies how much memory should be allocated 481 for the internal compression state. memLevel=1 uses minimum memory but 482 is slow and reduces compression ratio; memLevel=9 uses maximum memory 483 for optimal speed. The default value is 8. See zconf.h for total memory 484 usage as a function of windowBits and memLevel. 485 486 The strategy parameter is used to tune the compression algorithm. Use the 487 value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a 488 filter (or predictor), or Z_HUFFMAN_ONLY to force Huffman encoding only (no 489 string match). Filtered data consists mostly of small values with a 490 somewhat random distribution. In this case, the compression algorithm is 491 tuned to compress them better. The effect of Z_FILTERED is to force more 492 Huffman coding and less string matching; it is somewhat intermediate 493 between Z_DEFAULT and Z_HUFFMAN_ONLY. The strategy parameter only affects 494 the compression ratio but not the correctness of the compressed output even 495 if it is not set appropriately. 496 497 deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 498 memory, Z_STREAM_ERROR if a parameter is invalid (such as an invalid 499 method). msg is set to null if there is no error message. deflateInit2 does 500 not perform any compression: this will be done by deflate(). 501*/ 502 503extern int zlib_deflateReset (z_streamp strm); 504/* 505 This function is equivalent to deflateEnd followed by deflateInit, 506 but does not free and reallocate all the internal compression state. 507 The stream will keep the same compression level and any other attributes 508 that may have been set by deflateInit2. 509 510 deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source 511 stream state was inconsistent (such as zalloc or state being NULL). 512*/ 513 514static inline unsigned long deflateBound(unsigned long s) 515{ 516 return s + ((s + 7) >> 3) + ((s + 63) >> 6) + 11; 517} 518 519/* 520extern int inflateInit2 (z_streamp strm, int windowBits); 521 522 This is another version of inflateInit with an extra parameter. The 523 fields next_in, avail_in, zalloc, zfree and opaque must be initialized 524 before by the caller. 525 526 The windowBits parameter is the base two logarithm of the maximum window 527 size (the size of the history buffer). It should be in the range 8..15 for 528 this version of the library. The default value is 15 if inflateInit is used 529 instead. windowBits must be greater than or equal to the windowBits value 530 provided to deflateInit2() while compressing, or it must be equal to 15 if 531 deflateInit2() was not used. If a compressed stream with a larger window 532 size is given as input, inflate() will return with the error code 533 Z_DATA_ERROR instead of trying to allocate a larger window. 534 535 windowBits can also be -8..-15 for raw inflate. In this case, -windowBits 536 determines the window size. inflate() will then process raw deflate data, 537 not looking for a zlib or gzip header, not generating a check value, and not 538 looking for any check values for comparison at the end of the stream. This 539 is for use with other formats that use the deflate compressed data format 540 such as zip. Those formats provide their own check values. If a custom 541 format is developed using the raw deflate format for compressed data, it is 542 recommended that a check value such as an adler32 or a crc32 be applied to 543 the uncompressed data as is done in the zlib, gzip, and zip formats. For 544 most applications, the zlib format should be used as is. Note that comments 545 above on the use in deflateInit2() applies to the magnitude of windowBits. 546 547 windowBits can also be greater than 15 for optional gzip decoding. Add 548 32 to windowBits to enable zlib and gzip decoding with automatic header 549 detection, or add 16 to decode only the gzip format (the zlib format will 550 return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is 551 a crc32 instead of an adler32. 552 553 inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 554 memory, Z_STREAM_ERROR if a parameter is invalid (such as a null strm). msg 555 is set to null if there is no error message. inflateInit2 does not perform 556 any decompression apart from reading the zlib header if present: this will 557 be done by inflate(). (So next_in and avail_in may be modified, but next_out 558 and avail_out are unchanged.) 559*/ 560 561extern int zlib_inflateReset (z_streamp strm); 562/* 563 This function is equivalent to inflateEnd followed by inflateInit, 564 but does not free and reallocate all the internal decompression state. 565 The stream will keep attributes that may have been set by inflateInit2. 566 567 inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source 568 stream state was inconsistent (such as zalloc or state being NULL). 569*/ 570 571extern int zlib_inflateIncomp (z_stream *strm); 572/* 573 This function adds the data at next_in (avail_in bytes) to the output 574 history without performing any output. There must be no pending output, 575 and the decompressor must be expecting to see the start of a block. 576 Calling this function is equivalent to decompressing a stored block 577 containing the data at next_in (except that the data is not output). 578*/ 579 580#define zlib_deflateInit(strm, level) \ 581 zlib_deflateInit2((strm), (level), Z_DEFLATED, MAX_WBITS, \ 582 DEF_MEM_LEVEL, Z_DEFAULT_STRATEGY) 583#define zlib_inflateInit(strm) \ 584 zlib_inflateInit2((strm), DEF_WBITS) 585 586extern int zlib_deflateInit2(z_streamp strm, int level, int method, 587 int windowBits, int memLevel, 588 int strategy); 589extern int zlib_inflateInit2(z_streamp strm, int windowBits); 590 591#if !defined(_Z_UTIL_H) && !defined(NO_DUMMY_DECL) 592 struct internal_state {int dummy;}; /* hack for buggy compilers */ 593#endif 594 595/* Utility function: initialize zlib, unpack binary blob, clean up zlib, 596 * return len or negative error code. */ 597extern int zlib_inflate_blob(void *dst, unsigned dst_sz, const void *src, unsigned src_sz); 598 599#endif /* _ZLIB_H */ 600