1 #ifndef ZLIB_H_ 2 #define ZLIB_H_ 3 /* zlib.h -- interface of the 'zlib-ng' compression library 4 Forked from and compatible with zlib 1.2.11 5 6 Copyright (C) 1995-2016 Jean-loup Gailly and Mark Adler 7 8 This software is provided 'as-is', without any express or implied 9 warranty. In no event will the authors be held liable for any damages 10 arising from the use of this software. 11 12 Permission is granted to anyone to use this software for any purpose, 13 including commercial applications, and to alter it and redistribute it 14 freely, subject to the following restrictions: 15 16 1. The origin of this software must not be misrepresented; you must not 17 claim that you wrote the original software. If you use this software 18 in a product, an acknowledgment in the product documentation would be 19 appreciated but is not required. 20 2. Altered source versions must be plainly marked as such, and must not be 21 misrepresented as being the original software. 22 3. This notice may not be removed or altered from any source distribution. 23 24 Jean-loup Gailly Mark Adler 25 jloup@gzip.org madler@alumni.caltech.edu 26 27 28 The data format used by the zlib library is described by RFCs (Request for 29 Comments) 1950 to 1952 in the files https://tools.ietf.org/html/rfc1950 30 (zlib format), rfc1951 (deflate format) and rfc1952 (gzip format). 31 */ 32 33 #ifdef ZNGLIB_H_ 34 # error Include zlib-ng.h for zlib-ng API or zlib.h for zlib-compat API but not both 35 #endif 36 37 #include <stdint.h> 38 #include <stdarg.h> 39 #include "zconf.h" 40 41 #ifndef ZCONF_H 42 # error Missing zconf.h add binary output directory to include directories 43 #endif 44 45 #ifdef __cplusplus 46 extern "C" { 47 #endif 48 49 #define ZLIBNG_VERSION "2.0.5" 50 #define ZLIBNG_VERNUM 0x2050 51 #define ZLIBNG_VER_MAJOR 2 52 #define ZLIBNG_VER_MINOR 0 53 #define ZLIBNG_VER_REVISION 5 54 #define ZLIBNG_VER_SUBREVISION 0 55 56 #define ZLIB_VERSION "1.2.11.zlib-ng" 57 #define ZLIB_VERNUM 0x12bf 58 #define ZLIB_VER_MAJOR 1 59 #define ZLIB_VER_MINOR 2 60 #define ZLIB_VER_REVISION 11 61 #define ZLIB_VER_SUBREVISION 0 62 63 /* 64 The 'zlib' compression library provides in-memory compression and 65 decompression functions, including integrity checks of the uncompressed data. 66 This version of the library supports only one compression method (deflation) 67 but other algorithms will be added later and will have the same stream 68 interface. 69 70 Compression can be done in a single step if the buffers are large enough, 71 or can be done by repeated calls of the compression function. In the latter 72 case, the application must provide more input and/or consume the output 73 (providing more output space) before each call. 74 75 The compressed data format used by default by the in-memory functions is 76 the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped 77 around a deflate stream, which is itself documented in RFC 1951. 78 79 The library also supports reading and writing files in gzip (.gz) format 80 with an interface similar to that of stdio using the functions that start 81 with "gz". The gzip format is different from the zlib format. gzip is a 82 gzip wrapper, documented in RFC 1952, wrapped around a deflate stream. 83 84 This library can optionally read and write gzip and raw deflate streams in 85 memory as well. 86 87 The zlib format was designed to be compact and fast for use in memory 88 and on communications channels. The gzip format was designed for single- 89 file compression on file systems, has a larger header than zlib to maintain 90 directory information, and uses a different, slower check method than zlib. 91 92 The library does not install any signal handler. The decoder checks 93 the consistency of the compressed data, so the library should never crash 94 even in the case of corrupted input. 95 */ 96 97 typedef void *(*alloc_func) (void *opaque, unsigned int items, unsigned int size); 98 typedef void (*free_func) (void *opaque, void *address); 99 100 struct internal_state; 101 102 typedef struct z_stream_s { 103 z_const unsigned char *next_in; /* next input byte */ 104 uint32_t avail_in; /* number of bytes available at next_in */ 105 unsigned long total_in; /* total number of input bytes read so far */ 106 107 unsigned char *next_out; /* next output byte will go here */ 108 uint32_t avail_out; /* remaining free space at next_out */ 109 unsigned long total_out; /* total number of bytes output so far */ 110 111 z_const char *msg; /* last error message, NULL if no error */ 112 struct internal_state *state; /* not visible by applications */ 113 114 alloc_func zalloc; /* used to allocate the internal state */ 115 free_func zfree; /* used to free the internal state */ 116 void *opaque; /* private data object passed to zalloc and zfree */ 117 118 int data_type; /* best guess about the data type: binary or text 119 for deflate, or the decoding state for inflate */ 120 unsigned long adler; /* Adler-32 or CRC-32 value of the uncompressed data */ 121 unsigned long reserved; /* reserved for future use */ 122 } z_stream; 123 124 typedef z_stream *z_streamp; /* Obsolete type, retained for compatibility only */ 125 126 /* 127 gzip header information passed to and from zlib routines. See RFC 1952 128 for more details on the meanings of these fields. 129 */ 130 typedef struct gz_header_s { 131 int text; /* true if compressed data believed to be text */ 132 unsigned long time; /* modification time */ 133 int xflags; /* extra flags (not used when writing a gzip file) */ 134 int os; /* operating system */ 135 unsigned char *extra; /* pointer to extra field or NULL if none */ 136 unsigned int extra_len; /* extra field length (valid if extra != NULL) */ 137 unsigned int extra_max; /* space at extra (only when reading header) */ 138 unsigned char *name; /* pointer to zero-terminated file name or NULL */ 139 unsigned int name_max; /* space at name (only when reading header) */ 140 unsigned char *comment; /* pointer to zero-terminated comment or NULL */ 141 unsigned int comm_max; /* space at comment (only when reading header) */ 142 int hcrc; /* true if there was or will be a header crc */ 143 int done; /* true when done reading gzip header (not used when writing a gzip file) */ 144 } gz_header; 145 146 typedef gz_header *gz_headerp; 147 148 /* 149 The application must update next_in and avail_in when avail_in has dropped 150 to zero. It must update next_out and avail_out when avail_out has dropped 151 to zero. The application must initialize zalloc, zfree and opaque before 152 calling the init function. All other fields are set by the compression 153 library and must not be updated by the application. 154 155 The opaque value provided by the application will be passed as the first 156 parameter for calls of zalloc and zfree. This can be useful for custom 157 memory management. The compression library attaches no meaning to the 158 opaque value. 159 160 zalloc must return NULL if there is not enough memory for the object. 161 If zlib is used in a multi-threaded application, zalloc and zfree must be 162 thread safe. In that case, zlib is thread-safe. When zalloc and zfree are 163 Z_NULL on entry to the initialization function, they are set to internal 164 routines that use the standard library functions malloc() and free(). 165 166 The fields total_in and total_out can be used for statistics or progress 167 reports. After compression, total_in holds the total size of the 168 uncompressed data and may be saved for use by the decompressor (particularly 169 if the decompressor wants to decompress everything in a single step). 170 */ 171 172 /* constants */ 173 174 #define Z_NO_FLUSH 0 175 #define Z_PARTIAL_FLUSH 1 176 #define Z_SYNC_FLUSH 2 177 #define Z_FULL_FLUSH 3 178 #define Z_FINISH 4 179 #define Z_BLOCK 5 180 #define Z_TREES 6 181 /* Allowed flush values; see deflate() and inflate() below for details */ 182 183 #define Z_OK 0 184 #define Z_STREAM_END 1 185 #define Z_NEED_DICT 2 186 #define Z_ERRNO (-1) 187 #define Z_STREAM_ERROR (-2) 188 #define Z_DATA_ERROR (-3) 189 #define Z_MEM_ERROR (-4) 190 #define Z_BUF_ERROR (-5) 191 #define Z_VERSION_ERROR (-6) 192 /* Return codes for the compression/decompression functions. Negative values 193 * are errors, positive values are used for special but normal events. 194 */ 195 196 #define Z_NO_COMPRESSION 0 197 #define Z_BEST_SPEED 1 198 #define Z_BEST_COMPRESSION 9 199 #define Z_DEFAULT_COMPRESSION (-1) 200 /* compression levels */ 201 202 #define Z_FILTERED 1 203 #define Z_HUFFMAN_ONLY 2 204 #define Z_RLE 3 205 #define Z_FIXED 4 206 #define Z_DEFAULT_STRATEGY 0 207 /* compression strategy; see deflateInit2() below for details */ 208 209 #define Z_BINARY 0 210 #define Z_TEXT 1 211 #define Z_ASCII Z_TEXT /* for compatibility with 1.2.2 and earlier */ 212 #define Z_UNKNOWN 2 213 /* Possible values of the data_type field for deflate() */ 214 215 #define Z_DEFLATED 8 216 /* The deflate compression method (the only one supported in this version) */ 217 218 #define Z_NULL NULL /* for compatibility with zlib, was for initializing zalloc, zfree, opaque */ 219 220 #define zlib_version zlibVersion() 221 /* for compatibility with versions < 1.0.2 */ 222 223 224 /* basic functions */ 225 226 Z_EXTERN const char * Z_EXPORT zlibVersion(void); 227 /* The application can compare zlibVersion and ZLIB_VERSION for consistency. 228 If the first character differs, the library code actually used is not 229 compatible with the zlib.h header file used by the application. This check 230 is automatically made by deflateInit and inflateInit. 231 */ 232 233 /* 234 Z_EXTERN int Z_EXPORT deflateInit (z_stream *strm, int level); 235 236 Initializes the internal stream state for compression. The fields 237 zalloc, zfree and opaque must be initialized before by the caller. If 238 zalloc and zfree are set to NULL, deflateInit updates them to use default 239 allocation functions. 240 241 The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9: 242 1 gives best speed, 9 gives best compression, 0 gives no compression at all 243 (the input data is simply copied a block at a time). Z_DEFAULT_COMPRESSION 244 requests a default compromise between speed and compression (currently 245 equivalent to level 6). 246 247 deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough 248 memory, Z_STREAM_ERROR if level is not a valid compression level, or 249 Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible 250 with the version assumed by the caller (ZLIB_VERSION). msg is set to null 251 if there is no error message. deflateInit does not perform any compression: 252 this will be done by deflate(). 253 */ 254 255 256 Z_EXTERN int Z_EXPORT deflate(z_stream *strm, int flush); 257 /* 258 deflate compresses as much data as possible, and stops when the input 259 buffer becomes empty or the output buffer becomes full. It may introduce 260 some output latency (reading input without producing any output) except when 261 forced to flush. 262 263 The detailed semantics are as follows. deflate performs one or both of the 264 following actions: 265 266 - Compress more input starting at next_in and update next_in and avail_in 267 accordingly. If not all input can be processed (because there is not 268 enough room in the output buffer), next_in and avail_in are updated and 269 processing will resume at this point for the next call of deflate(). 270 271 - Generate more output starting at next_out and update next_out and avail_out 272 accordingly. This action is forced if the parameter flush is non zero. 273 Forcing flush frequently degrades the compression ratio, so this parameter 274 should be set only when necessary. Some output may be provided even if 275 flush is zero. 276 277 Before the call of deflate(), the application should ensure that at least 278 one of the actions is possible, by providing more input and/or consuming more 279 output, and updating avail_in or avail_out accordingly; avail_out should 280 never be zero before the call. The application can consume the compressed 281 output when it wants, for example when the output buffer is full (avail_out 282 == 0), or after each call of deflate(). If deflate returns Z_OK and with 283 zero avail_out, it must be called again after making room in the output 284 buffer because there might be more output pending. See deflatePending(), 285 which can be used if desired to determine whether or not there is more output 286 in that case. 287 288 Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to 289 decide how much data to accumulate before producing output, in order to 290 maximize compression. 291 292 If the parameter flush is set to Z_SYNC_FLUSH, all pending output is 293 flushed to the output buffer and the output is aligned on a byte boundary, so 294 that the decompressor can get all input data available so far. (In 295 particular avail_in is zero after the call if enough output space has been 296 provided before the call.) Flushing may degrade compression for some 297 compression algorithms and so it should be used only when necessary. This 298 completes the current deflate block and follows it with an empty stored block 299 that is three bits plus filler bits to the next byte, followed by four bytes 300 (00 00 ff ff). 301 302 If flush is set to Z_PARTIAL_FLUSH, all pending output is flushed to the 303 output buffer, but the output is not aligned to a byte boundary. All of the 304 input data so far will be available to the decompressor, as for Z_SYNC_FLUSH. 305 This completes the current deflate block and follows it with an empty fixed 306 codes block that is 10 bits long. This assures that enough bytes are output 307 in order for the decompressor to finish the block before the empty fixed 308 codes block. 309 310 If flush is set to Z_BLOCK, a deflate block is completed and emitted, as 311 for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to 312 seven bits of the current block are held to be written as the next byte after 313 the next deflate block is completed. In this case, the decompressor may not 314 be provided enough bits at this point in order to complete decompression of 315 the data provided so far to the compressor. It may need to wait for the next 316 block to be emitted. This is for advanced applications that need to control 317 the emission of deflate blocks. 318 319 If flush is set to Z_FULL_FLUSH, all output is flushed as with 320 Z_SYNC_FLUSH, and the compression state is reset so that decompression can 321 restart from this point if previous compressed data has been damaged or if 322 random access is desired. Using Z_FULL_FLUSH too often can seriously degrade 323 compression. 324 325 If deflate returns with avail_out == 0, this function must be called again 326 with the same value of the flush parameter and more output space (updated 327 avail_out), until the flush is complete (deflate returns with non-zero 328 avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that 329 avail_out is greater than six to avoid repeated flush markers due to 330 avail_out == 0 on return. 331 332 If the parameter flush is set to Z_FINISH, pending input is processed, 333 pending output is flushed and deflate returns with Z_STREAM_END if there was 334 enough output space. If deflate returns with Z_OK or Z_BUF_ERROR, this 335 function must be called again with Z_FINISH and more output space (updated 336 avail_out) but no more input data, until it returns with Z_STREAM_END or an 337 error. After deflate has returned Z_STREAM_END, the only possible operations 338 on the stream are deflateReset or deflateEnd. 339 340 Z_FINISH can be used in the first deflate call after deflateInit if all the 341 compression is to be done in a single step. In order to complete in one 342 call, avail_out must be at least the value returned by deflateBound (see 343 below). Then deflate is guaranteed to return Z_STREAM_END. If not enough 344 output space is provided, deflate will not return Z_STREAM_END, and it must 345 be called again as described above. 346 347 deflate() sets strm->adler to the Adler-32 checksum of all input read 348 so far (that is, total_in bytes). If a gzip stream is being generated, then 349 strm->adler will be the CRC-32 checksum of the input read so far. (See 350 deflateInit2 below.) 351 352 deflate() may update strm->data_type if it can make a good guess about 353 the input data type (Z_BINARY or Z_TEXT). If in doubt, the data is 354 considered binary. This field is only for information purposes and does not 355 affect the compression algorithm in any manner. 356 357 deflate() returns Z_OK if some progress has been made (more input 358 processed or more output produced), Z_STREAM_END if all input has been 359 consumed and all output has been produced (only when flush is set to 360 Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example 361 if next_in or next_out was NULL) or the state was inadvertently written over 362 by the application), or Z_BUF_ERROR if no progress is possible (for example 363 avail_in or avail_out was zero). Note that Z_BUF_ERROR is not fatal, and 364 deflate() can be called again with more input and more output space to 365 continue compressing. 366 */ 367 368 369 Z_EXTERN int Z_EXPORT deflateEnd(z_stream *strm); 370 /* 371 All dynamically allocated data structures for this stream are freed. 372 This function discards any unprocessed input and does not flush any pending 373 output. 374 375 deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the 376 stream state was inconsistent, Z_DATA_ERROR if the stream was freed 377 prematurely (some input or output was discarded). In the error case, msg 378 may be set but then points to a static string (which must not be 379 deallocated). 380 */ 381 382 383 /* 384 Z_EXTERN int Z_EXPORT inflateInit (z_stream *strm); 385 386 Initializes the internal stream state for decompression. The fields 387 next_in, avail_in, zalloc, zfree and opaque must be initialized before by 388 the caller. In the current version of inflate, the provided input is not 389 read or consumed. The allocation of a sliding window will be deferred to 390 the first call of inflate (if the decompression does not complete on the 391 first call). If zalloc and zfree are set to NULL, inflateInit updates 392 them to use default allocation functions. 393 394 inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough 395 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the 396 version assumed by the caller, or Z_STREAM_ERROR if the parameters are 397 invalid, such as a null pointer to the structure. msg is set to null if 398 there is no error message. inflateInit does not perform any decompression. 399 Actual decompression will be done by inflate(). So next_in, and avail_in, 400 next_out, and avail_out are unused and unchanged. The current 401 implementation of inflateInit() does not process any header information -- 402 that is deferred until inflate() is called. 403 */ 404 405 406 Z_EXTERN int Z_EXPORT inflate(z_stream *strm, int flush); 407 /* 408 inflate decompresses as much data as possible, and stops when the input 409 buffer becomes empty or the output buffer becomes full. It may introduce 410 some output latency (reading input without producing any output) except when 411 forced to flush. 412 413 The detailed semantics are as follows. inflate performs one or both of the 414 following actions: 415 416 - Decompress more input starting at next_in and update next_in and avail_in 417 accordingly. If not all input can be processed (because there is not 418 enough room in the output buffer), then next_in and avail_in are updated 419 accordingly, and processing will resume at this point for the next call of 420 inflate(). 421 422 - Generate more output starting at next_out and update next_out and avail_out 423 accordingly. inflate() provides as much output as possible, until there is 424 no more input data or no more space in the output buffer (see below about 425 the flush parameter). 426 427 Before the call of inflate(), the application should ensure that at least 428 one of the actions is possible, by providing more input and/or consuming more 429 output, and updating the next_* and avail_* values accordingly. If the 430 caller of inflate() does not provide both available input and available 431 output space, it is possible that there will be no progress made. The 432 application can consume the uncompressed output when it wants, for example 433 when the output buffer is full (avail_out == 0), or after each call of 434 inflate(). If inflate returns Z_OK and with zero avail_out, it must be 435 called again after making room in the output buffer because there might be 436 more output pending. 437 438 The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, Z_FINISH, 439 Z_BLOCK, or Z_TREES. Z_SYNC_FLUSH requests that inflate() flush as much 440 output as possible to the output buffer. Z_BLOCK requests that inflate() 441 stop if and when it gets to the next deflate block boundary. When decoding 442 the zlib or gzip format, this will cause inflate() to return immediately 443 after the header and before the first block. When doing a raw inflate, 444 inflate() will go ahead and process the first block, and will return when it 445 gets to the end of that block, or when it runs out of data. 446 447 The Z_BLOCK option assists in appending to or combining deflate streams. 448 To assist in this, on return inflate() always sets strm->data_type to the 449 number of unused bits in the last byte taken from strm->next_in, plus 64 if 450 inflate() is currently decoding the last block in the deflate stream, plus 451 128 if inflate() returned immediately after decoding an end-of-block code or 452 decoding the complete header up to just before the first byte of the deflate 453 stream. The end-of-block will not be indicated until all of the uncompressed 454 data from that block has been written to strm->next_out. The number of 455 unused bits may in general be greater than seven, except when bit 7 of 456 data_type is set, in which case the number of unused bits will be less than 457 eight. data_type is set as noted here every time inflate() returns for all 458 flush options, and so can be used to determine the amount of currently 459 consumed input in bits. 460 461 The Z_TREES option behaves as Z_BLOCK does, but it also returns when the 462 end of each deflate block header is reached, before any actual data in that 463 block is decoded. This allows the caller to determine the length of the 464 deflate block header for later use in random access within a deflate block. 465 256 is added to the value of strm->data_type when inflate() returns 466 immediately after reaching the end of the deflate block header. 467 468 inflate() should normally be called until it returns Z_STREAM_END or an 469 error. However if all decompression is to be performed in a single step (a 470 single call of inflate), the parameter flush should be set to Z_FINISH. In 471 this case all pending input is processed and all pending output is flushed; 472 avail_out must be large enough to hold all of the uncompressed data for the 473 operation to complete. (The size of the uncompressed data may have been 474 saved by the compressor for this purpose.) The use of Z_FINISH is not 475 required to perform an inflation in one step. However it may be used to 476 inform inflate that a faster approach can be used for the single inflate() 477 call. Z_FINISH also informs inflate to not maintain a sliding window if the 478 stream completes, which reduces inflate's memory footprint. If the stream 479 does not complete, either because not all of the stream is provided or not 480 enough output space is provided, then a sliding window will be allocated and 481 inflate() can be called again to continue the operation as if Z_NO_FLUSH had 482 been used. 483 484 In this implementation, inflate() always flushes as much output as 485 possible to the output buffer, and always uses the faster approach on the 486 first call. So the effects of the flush parameter in this implementation are 487 on the return value of inflate() as noted below, when inflate() returns early 488 when Z_BLOCK or Z_TREES is used, and when inflate() avoids the allocation of 489 memory for a sliding window when Z_FINISH is used. 490 491 If a preset dictionary is needed after this call (see inflateSetDictionary 492 below), inflate sets strm->adler to the Adler-32 checksum of the dictionary 493 chosen by the compressor and returns Z_NEED_DICT; otherwise it sets 494 strm->adler to the Adler-32 checksum of all output produced so far (that is, 495 total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described 496 below. At the end of the stream, inflate() checks that its computed Adler-32 497 checksum is equal to that saved by the compressor and returns Z_STREAM_END 498 only if the checksum is correct. 499 500 inflate() can decompress and check either zlib-wrapped or gzip-wrapped 501 deflate data. The header type is detected automatically, if requested when 502 initializing with inflateInit2(). Any information contained in the gzip 503 header is not retained unless inflateGetHeader() is used. When processing 504 gzip-wrapped deflate data, strm->adler32 is set to the CRC-32 of the output 505 produced so far. The CRC-32 is checked against the gzip trailer, as is the 506 uncompressed length, modulo 2^32. 507 508 inflate() returns Z_OK if some progress has been made (more input processed 509 or more output produced), Z_STREAM_END if the end of the compressed data has 510 been reached and all uncompressed output has been produced, Z_NEED_DICT if a 511 preset dictionary is needed at this point, Z_DATA_ERROR if the input data was 512 corrupted (input stream not conforming to the zlib format or incorrect check 513 value, in which case strm->msg points to a string with a more specific 514 error), Z_STREAM_ERROR if the stream structure was inconsistent (for example 515 next_in or next_out was NULL, or the state was inadvertently written over 516 by the application), Z_MEM_ERROR if there was not enough memory, Z_BUF_ERROR 517 if no progress is possible or if there was not enough room in the output 518 buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and 519 inflate() can be called again with more input and more output space to 520 continue decompressing. If Z_DATA_ERROR is returned, the application may 521 then call inflateSync() to look for a good compression block if a partial 522 recovery of the data is to be attempted. 523 */ 524 525 526 Z_EXTERN int Z_EXPORT inflateEnd(z_stream *strm); 527 /* 528 All dynamically allocated data structures for this stream are freed. 529 This function discards any unprocessed input and does not flush any pending 530 output. 531 532 inflateEnd returns Z_OK if success, or Z_STREAM_ERROR if the stream state 533 was inconsistent. 534 */ 535 536 537 /* Advanced functions */ 538 539 /* 540 The following functions are needed only in some special applications. 541 */ 542 543 /* 544 Z_EXTERN int Z_EXPORT deflateInit2 (z_stream *strm, 545 int level, 546 int method, 547 int windowBits, 548 int memLevel, 549 int strategy); 550 551 This is another version of deflateInit with more compression options. The 552 fields zalloc, zfree and opaque must be initialized before by the caller. 553 554 The method parameter is the compression method. It must be Z_DEFLATED in 555 this version of the library. 556 557 The windowBits parameter is the base two logarithm of the window size 558 (the size of the history buffer). It should be in the range 8..15 for this 559 version of the library. Larger values of this parameter result in better 560 compression at the expense of memory usage. The default value is 15 if 561 deflateInit is used instead. 562 563 For the current implementation of deflate(), a windowBits value of 8 (a 564 window size of 256 bytes) is not supported. As a result, a request for 8 565 will result in 9 (a 512-byte window). In that case, providing 8 to 566 inflateInit2() will result in an error when the zlib header with 9 is 567 checked against the initialization of inflate(). The remedy is to not use 8 568 with deflateInit2() with this initialization, or at least in that case use 9 569 with inflateInit2(). 570 571 windowBits can also be -8..-15 for raw deflate. In this case, -windowBits 572 determines the window size. deflate() will then generate raw deflate data 573 with no zlib header or trailer, and will not compute a check value. 574 575 windowBits can also be greater than 15 for optional gzip encoding. Add 576 16 to windowBits to write a simple gzip header and trailer around the 577 compressed data instead of a zlib wrapper. The gzip header will have no 578 file name, no extra data, no comment, no modification time (set to zero), no 579 header crc, and the operating system will be set to the appropriate value, 580 if the operating system was determined at compile time. If a gzip stream is 581 being written, strm->adler is a CRC-32 instead of an Adler-32. 582 583 For raw deflate or gzip encoding, a request for a 256-byte window is 584 rejected as invalid, since only the zlib header provides a means of 585 transmitting the window size to the decompressor. 586 587 The memLevel parameter specifies how much memory should be allocated 588 for the internal compression state. memLevel=1 uses minimum memory but is 589 slow and reduces compression ratio; memLevel=9 uses maximum memory for 590 optimal speed. The default value is 8. See zconf.h for total memory usage 591 as a function of windowBits and memLevel. 592 593 The strategy parameter is used to tune the compression algorithm. Use the 594 value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a 595 filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no 596 string match), or Z_RLE to limit match distances to one (run-length 597 encoding). Filtered data consists mostly of small values with a somewhat 598 random distribution. In this case, the compression algorithm is tuned to 599 compress them better. The effect of Z_FILTERED is to force more Huffman 600 coding and less string matching; it is somewhat intermediate between 601 Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as 602 fast as Z_HUFFMAN_ONLY, but give better compression for PNG image data. The 603 strategy parameter only affects the compression ratio but not the 604 correctness of the compressed output even if it is not set appropriately. 605 Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler 606 decoder for special applications. 607 608 deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 609 memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid 610 method), or Z_VERSION_ERROR if the zlib library version (zlib_version) is 611 incompatible with the version assumed by the caller (ZLIB_VERSION). msg is 612 set to null if there is no error message. deflateInit2 does not perform any 613 compression: this will be done by deflate(). 614 */ 615 616 Z_EXTERN int Z_EXPORT deflateSetDictionary(z_stream *strm, 617 const unsigned char *dictionary, 618 unsigned int dictLength); 619 /* 620 Initializes the compression dictionary from the given byte sequence 621 without producing any compressed output. When using the zlib format, this 622 function must be called immediately after deflateInit, deflateInit2 or 623 deflateReset, and before any call of deflate. When doing raw deflate, this 624 function must be called either before any call of deflate, or immediately 625 after the completion of a deflate block, i.e. after all input has been 626 consumed and all output has been delivered when using any of the flush 627 options Z_BLOCK, Z_PARTIAL_FLUSH, Z_SYNC_FLUSH, or Z_FULL_FLUSH. The 628 compressor and decompressor must use exactly the same dictionary (see 629 inflateSetDictionary). 630 631 The dictionary should consist of strings (byte sequences) that are likely 632 to be encountered later in the data to be compressed, with the most commonly 633 used strings preferably put towards the end of the dictionary. Using a 634 dictionary is most useful when the data to be compressed is short and can be 635 predicted with good accuracy; the data can then be compressed better than 636 with the default empty dictionary. 637 638 Depending on the size of the compression data structures selected by 639 deflateInit or deflateInit2, a part of the dictionary may in effect be 640 discarded, for example if the dictionary is larger than the window size 641 provided in deflateInit or deflateInit2. Thus the strings most likely to be 642 useful should be put at the end of the dictionary, not at the front. In 643 addition, the current implementation of deflate will use at most the window 644 size minus 262 bytes of the provided dictionary. 645 646 Upon return of this function, strm->adler is set to the Adler-32 value 647 of the dictionary; the decompressor may later use this value to determine 648 which dictionary has been used by the compressor. (The Adler-32 value 649 applies to the whole dictionary even if only a subset of the dictionary is 650 actually used by the compressor.) If a raw deflate was requested, then the 651 Adler-32 value is not computed and strm->adler is not set. 652 653 deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a 654 parameter is invalid (e.g. dictionary being NULL) or the stream state is 655 inconsistent (for example if deflate has already been called for this stream 656 or if not at a block boundary for raw deflate). deflateSetDictionary does 657 not perform any compression: this will be done by deflate(). 658 */ 659 660 Z_EXTERN int Z_EXPORT deflateGetDictionary (z_stream *strm, unsigned char *dictionary, unsigned int *dictLength); 661 /* 662 Returns the sliding dictionary being maintained by deflate. dictLength is 663 set to the number of bytes in the dictionary, and that many bytes are copied 664 to dictionary. dictionary must have enough space, where 32768 bytes is 665 always enough. If deflateGetDictionary() is called with dictionary equal to 666 Z_NULL, then only the dictionary length is returned, and nothing is copied. 667 Similarly, if dictLength is Z_NULL, then it is not set. 668 669 deflateGetDictionary() may return a length less than the window size, even 670 when more than the window size in input has been provided. It may return up 671 to 258 bytes less in that case, due to how zlib's implementation of deflate 672 manages the sliding window and lookahead for matches, where matches can be 673 up to 258 bytes long. If the application needs the last window-size bytes of 674 input, then that would need to be saved by the application outside of zlib. 675 676 deflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the 677 stream state is inconsistent. 678 */ 679 680 Z_EXTERN int Z_EXPORT deflateCopy(z_stream *dest, z_stream *source); 681 /* 682 Sets the destination stream as a complete copy of the source stream. 683 684 This function can be useful when several compression strategies will be 685 tried, for example when there are several ways of pre-processing the input 686 data with a filter. The streams that will be discarded should then be freed 687 by calling deflateEnd. Note that deflateCopy duplicates the internal 688 compression state which can be quite large, so this strategy is slow and can 689 consume lots of memory. 690 691 deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not 692 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent 693 (such as zalloc being NULL). msg is left unchanged in both source and 694 destination. 695 */ 696 697 Z_EXTERN int Z_EXPORT deflateReset(z_stream *strm); 698 /* 699 This function is equivalent to deflateEnd followed by deflateInit, but 700 does not free and reallocate the internal compression state. The stream 701 will leave the compression level and any other attributes that may have been 702 set unchanged. 703 704 deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source 705 stream state was inconsistent (such as zalloc or state being NULL). 706 */ 707 708 Z_EXTERN int Z_EXPORT deflateParams(z_stream *strm, int level, int strategy); 709 /* 710 Dynamically update the compression level and compression strategy. The 711 interpretation of level and strategy is as in deflateInit2(). This can be 712 used to switch between compression and straight copy of the input data, or 713 to switch to a different kind of input data requiring a different strategy. 714 If the compression approach (which is a function of the level) or the 715 strategy is changed, and if there have been any deflate() calls since the 716 state was initialized or reset, then the input available so far is 717 compressed with the old level and strategy using deflate(strm, Z_BLOCK). 718 There are three approaches for the compression levels 0, 1..3, and 4..9 719 respectively. The new level and strategy will take effect at the next call 720 of deflate(). 721 722 If a deflate(strm, Z_BLOCK) is performed by deflateParams(), and it does 723 not have enough output space to complete, then the parameter change will not 724 take effect. In this case, deflateParams() can be called again with the 725 same parameters and more output space to try again. 726 727 In order to assure a change in the parameters on the first try, the 728 deflate stream should be flushed using deflate() with Z_BLOCK or other flush 729 request until strm.avail_out is not zero, before calling deflateParams(). 730 Then no more input data should be provided before the deflateParams() call. 731 If this is done, the old level and strategy will be applied to the data 732 compressed before deflateParams(), and the new level and strategy will be 733 applied to the the data compressed after deflateParams(). 734 735 deflateParams returns Z_OK on success, Z_STREAM_ERROR if the source stream 736 state was inconsistent or if a parameter was invalid, or Z_BUF_ERROR if 737 there was not enough output space to complete the compression of the 738 available input data before a change in the strategy or approach. Note that 739 in the case of a Z_BUF_ERROR, the parameters are not changed. A return 740 value of Z_BUF_ERROR is not fatal, in which case deflateParams() can be 741 retried with more output space. 742 */ 743 744 Z_EXTERN int Z_EXPORT deflateTune(z_stream *strm, int good_length, int max_lazy, int nice_length, int max_chain); 745 /* 746 Fine tune deflate's internal compression parameters. This should only be 747 used by someone who understands the algorithm used by zlib's deflate for 748 searching for the best matching string, and even then only by the most 749 fanatic optimizer trying to squeeze out the last compressed bit for their 750 specific input data. Read the deflate.c source code for the meaning of the 751 max_lazy, good_length, nice_length, and max_chain parameters. 752 753 deflateTune() can be called after deflateInit() or deflateInit2(), and 754 returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream. 755 */ 756 757 Z_EXTERN unsigned long Z_EXPORT deflateBound(z_stream *strm, unsigned long sourceLen); 758 /* 759 deflateBound() returns an upper bound on the compressed size after 760 deflation of sourceLen bytes. It must be called after deflateInit() or 761 deflateInit2(), and after deflateSetHeader(), if used. This would be used 762 to allocate an output buffer for deflation in a single pass, and so would be 763 called before deflate(). If that first deflate() call is provided the 764 sourceLen input bytes, an output buffer allocated to the size returned by 765 deflateBound(), and the flush value Z_FINISH, then deflate() is guaranteed 766 to return Z_STREAM_END. Note that it is possible for the compressed size to 767 be larger than the value returned by deflateBound() if flush options other 768 than Z_FINISH or Z_NO_FLUSH are used. 769 */ 770 771 Z_EXTERN int Z_EXPORT deflatePending(z_stream *strm, uint32_t *pending, int *bits); 772 /* 773 deflatePending() returns the number of bytes and bits of output that have 774 been generated, but not yet provided in the available output. The bytes not 775 provided would be due to the available output space having being consumed. 776 The number of bits of output not provided are between 0 and 7, where they 777 await more bits to join them in order to fill out a full byte. If pending 778 or bits are NULL, then those values are not set. 779 780 deflatePending returns Z_OK if success, or Z_STREAM_ERROR if the source 781 stream state was inconsistent. 782 */ 783 784 Z_EXTERN int Z_EXPORT deflatePrime(z_stream *strm, int bits, int value); 785 /* 786 deflatePrime() inserts bits in the deflate output stream. The intent 787 is that this function is used to start off the deflate output with the bits 788 leftover from a previous deflate stream when appending to it. As such, this 789 function can only be used for raw deflate, and must be used before the first 790 deflate() call after a deflateInit2() or deflateReset(). bits must be less 791 than or equal to 16, and that many of the least significant bits of value 792 will be inserted in the output. 793 794 deflatePrime returns Z_OK if success, Z_BUF_ERROR if there was not enough 795 room in the internal buffer to insert the bits, or Z_STREAM_ERROR if the 796 source stream state was inconsistent. 797 */ 798 799 Z_EXTERN int Z_EXPORT deflateSetHeader(z_stream *strm, gz_headerp head); 800 /* 801 deflateSetHeader() provides gzip header information for when a gzip 802 stream is requested by deflateInit2(). deflateSetHeader() may be called 803 after deflateInit2() or deflateReset() and before the first call of 804 deflate(). The text, time, os, extra field, name, and comment information 805 in the provided gz_header structure are written to the gzip header (xflag is 806 ignored -- the extra flags are set according to the compression level). The 807 caller must assure that, if not NULL, name and comment are terminated with 808 a zero byte, and that if extra is not NULL, that extra_len bytes are 809 available there. If hcrc is true, a gzip header crc is included. Note that 810 the current versions of the command-line version of gzip (up through version 811 1.3.x) do not support header crc's, and will report that it is a "multi-part 812 gzip file" and give up. 813 814 If deflateSetHeader is not used, the default gzip header has text false, 815 the time set to zero, and os set to 255, with no extra, name, or comment 816 fields. The gzip header is returned to the default state by deflateReset(). 817 818 deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source 819 stream state was inconsistent. 820 */ 821 822 /* 823 Z_EXTERN int Z_EXPORT inflateInit2(z_stream *strm, int windowBits); 824 825 This is another version of inflateInit with an extra parameter. The 826 fields next_in, avail_in, zalloc, zfree and opaque must be initialized 827 before by the caller. 828 829 The windowBits parameter is the base two logarithm of the maximum window 830 size (the size of the history buffer). It should be in the range 8..15 for 831 this version of the library. The default value is 15 if inflateInit is used 832 instead. windowBits must be greater than or equal to the windowBits value 833 provided to deflateInit2() while compressing, or it must be equal to 15 if 834 deflateInit2() was not used. If a compressed stream with a larger window 835 size is given as input, inflate() will return with the error code 836 Z_DATA_ERROR instead of trying to allocate a larger window. 837 838 windowBits can also be zero to request that inflate use the window size in 839 the zlib header of the compressed stream. 840 841 windowBits can also be -8..-15 for raw inflate. In this case, -windowBits 842 determines the window size. inflate() will then process raw deflate data, 843 not looking for a zlib or gzip header, not generating a check value, and not 844 looking for any check values for comparison at the end of the stream. This 845 is for use with other formats that use the deflate compressed data format 846 such as zip. Those formats provide their own check values. If a custom 847 format is developed using the raw deflate format for compressed data, it is 848 recommended that a check value such as an Adler-32 or a CRC-32 be applied to 849 the uncompressed data as is done in the zlib, gzip, and zip formats. For 850 most applications, the zlib format should be used as is. Note that comments 851 above on the use in deflateInit2() applies to the magnitude of windowBits. 852 853 windowBits can also be greater than 15 for optional gzip decoding. Add 854 32 to windowBits to enable zlib and gzip decoding with automatic header 855 detection, or add 16 to decode only the gzip format (the zlib format will 856 return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is a 857 CRC-32 instead of an Adler-32. Unlike the gunzip utility and gzread() (see 858 below), inflate() will *not* automatically decode concatenated gzip members. 859 inflate() will return Z_STREAM_END at the end of the gzip member. The state 860 would need to be reset to continue decoding a subsequent gzip member. This 861 *must* be done if there is more data after a gzip member, in order for the 862 decompression to be compliant with the gzip standard (RFC 1952). 863 864 inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 865 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the 866 version assumed by the caller, or Z_STREAM_ERROR if the parameters are 867 invalid, such as a null pointer to the structure. msg is set to null if 868 there is no error message. inflateInit2 does not perform any decompression 869 apart from possibly reading the zlib header if present: actual decompression 870 will be done by inflate(). (So next_in and avail_in may be modified, but 871 next_out and avail_out are unused and unchanged.) The current implementation 872 of inflateInit2() does not process any header information -- that is 873 deferred until inflate() is called. 874 */ 875 876 Z_EXTERN int Z_EXPORT inflateSetDictionary(z_stream *strm, const unsigned char *dictionary, unsigned int dictLength); 877 /* 878 Initializes the decompression dictionary from the given uncompressed byte 879 sequence. This function must be called immediately after a call of inflate, 880 if that call returned Z_NEED_DICT. The dictionary chosen by the compressor 881 can be determined from the Adler-32 value returned by that call of inflate. 882 The compressor and decompressor must use exactly the same dictionary (see 883 deflateSetDictionary). For raw inflate, this function can be called at any 884 time to set the dictionary. If the provided dictionary is smaller than the 885 window and there is already data in the window, then the provided dictionary 886 will amend what's there. The application must insure that the dictionary 887 that was used for compression is provided. 888 889 inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a 890 parameter is invalid (e.g. dictionary being NULL) or the stream state is 891 inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the 892 expected one (incorrect Adler-32 value). inflateSetDictionary does not 893 perform any decompression: this will be done by subsequent calls of 894 inflate(). 895 */ 896 897 Z_EXTERN int Z_EXPORT inflateGetDictionary(z_stream *strm, unsigned char *dictionary, unsigned int *dictLength); 898 /* 899 Returns the sliding dictionary being maintained by inflate. dictLength is 900 set to the number of bytes in the dictionary, and that many bytes are copied 901 to dictionary. dictionary must have enough space, where 32768 bytes is 902 always enough. If inflateGetDictionary() is called with dictionary equal to 903 NULL, then only the dictionary length is returned, and nothing is copied. 904 Similarly, if dictLength is NULL, then it is not set. 905 906 inflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the 907 stream state is inconsistent. 908 */ 909 910 Z_EXTERN int Z_EXPORT inflateSync(z_stream *strm); 911 /* 912 Skips invalid compressed data until a possible full flush point (see above 913 for the description of deflate with Z_FULL_FLUSH) can be found, or until all 914 available input is skipped. No output is provided. 915 916 inflateSync searches for a 00 00 FF FF pattern in the compressed data. 917 All full flush points have this pattern, but not all occurrences of this 918 pattern are full flush points. 919 920 inflateSync returns Z_OK if a possible full flush point has been found, 921 Z_BUF_ERROR if no more input was provided, Z_DATA_ERROR if no flush point 922 has been found, or Z_STREAM_ERROR if the stream structure was inconsistent. 923 In the success case, the application may save the current current value of 924 total_in which indicates where valid compressed data was found. In the 925 error case, the application may repeatedly call inflateSync, providing more 926 input each time, until success or end of the input data. 927 */ 928 929 Z_EXTERN int Z_EXPORT inflateCopy(z_stream *dest, z_stream *source); 930 /* 931 Sets the destination stream as a complete copy of the source stream. 932 933 This function can be useful when randomly accessing a large stream. The 934 first pass through the stream can periodically record the inflate state, 935 allowing restarting inflate at those points when randomly accessing the 936 stream. 937 938 inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not 939 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent 940 (such as zalloc being NULL). msg is left unchanged in both source and 941 destination. 942 */ 943 944 Z_EXTERN int Z_EXPORT inflateReset(z_stream *strm); 945 /* 946 This function is equivalent to inflateEnd followed by inflateInit, 947 but does not free and reallocate the internal decompression state. The 948 stream will keep attributes that may have been set by inflateInit2. 949 950 inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source 951 stream state was inconsistent (such as zalloc or state being NULL). 952 */ 953 954 Z_EXTERN int Z_EXPORT inflateReset2(z_stream *strm, int windowBits); 955 /* 956 This function is the same as inflateReset, but it also permits changing 957 the wrap and window size requests. The windowBits parameter is interpreted 958 the same as it is for inflateInit2. If the window size is changed, then the 959 memory allocated for the window is freed, and the window will be reallocated 960 by inflate() if needed. 961 962 inflateReset2 returns Z_OK if success, or Z_STREAM_ERROR if the source 963 stream state was inconsistent (such as zalloc or state being NULL), or if 964 the windowBits parameter is invalid. 965 */ 966 967 Z_EXTERN int Z_EXPORT inflatePrime(z_stream *strm, int bits, int value); 968 /* 969 This function inserts bits in the inflate input stream. The intent is 970 that this function is used to start inflating at a bit position in the 971 middle of a byte. The provided bits will be used before any bytes are used 972 from next_in. This function should only be used with raw inflate, and 973 should be used before the first inflate() call after inflateInit2() or 974 inflateReset(). bits must be less than or equal to 16, and that many of the 975 least significant bits of value will be inserted in the input. 976 977 If bits is negative, then the input stream bit buffer is emptied. Then 978 inflatePrime() can be called again to put bits in the buffer. This is used 979 to clear out bits leftover after feeding inflate a block description prior 980 to feeding inflate codes. 981 982 inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source 983 stream state was inconsistent. 984 */ 985 986 Z_EXTERN long Z_EXPORT inflateMark(z_stream *strm); 987 /* 988 This function returns two values, one in the lower 16 bits of the return 989 value, and the other in the remaining upper bits, obtained by shifting the 990 return value down 16 bits. If the upper value is -1 and the lower value is 991 zero, then inflate() is currently decoding information outside of a block. 992 If the upper value is -1 and the lower value is non-zero, then inflate is in 993 the middle of a stored block, with the lower value equaling the number of 994 bytes from the input remaining to copy. If the upper value is not -1, then 995 it is the number of bits back from the current bit position in the input of 996 the code (literal or length/distance pair) currently being processed. In 997 that case the lower value is the number of bytes already emitted for that 998 code. 999 1000 A code is being processed if inflate is waiting for more input to complete 1001 decoding of the code, or if it has completed decoding but is waiting for 1002 more output space to write the literal or match data. 1003 1004 inflateMark() is used to mark locations in the input data for random 1005 access, which may be at bit positions, and to note those cases where the 1006 output of a code may span boundaries of random access blocks. The current 1007 location in the input stream can be determined from avail_in and data_type 1008 as noted in the description for the Z_BLOCK flush parameter for inflate. 1009 1010 inflateMark returns the value noted above, or -65536 if the provided 1011 source stream state was inconsistent. 1012 */ 1013 1014 Z_EXTERN int Z_EXPORT inflateGetHeader(z_stream *strm, gz_headerp head); 1015 /* 1016 inflateGetHeader() requests that gzip header information be stored in the 1017 provided gz_header structure. inflateGetHeader() may be called after 1018 inflateInit2() or inflateReset(), and before the first call of inflate(). 1019 As inflate() processes the gzip stream, head->done is zero until the header 1020 is completed, at which time head->done is set to one. If a zlib stream is 1021 being decoded, then head->done is set to -1 to indicate that there will be 1022 no gzip header information forthcoming. Note that Z_BLOCK or Z_TREES can be 1023 used to force inflate() to return immediately after header processing is 1024 complete and before any actual data is decompressed. 1025 1026 The text, time, xflags, and os fields are filled in with the gzip header 1027 contents. hcrc is set to true if there is a header CRC. (The header CRC 1028 was valid if done is set to one.) If extra is not NULL, then extra_max 1029 contains the maximum number of bytes to write to extra. Once done is true, 1030 extra_len contains the actual extra field length, and extra contains the 1031 extra field, or that field truncated if extra_max is less than extra_len. 1032 If name is not NULL, then up to name_max characters are written there, 1033 terminated with a zero unless the length is greater than name_max. If 1034 comment is not NULL, then up to comm_max characters are written there, 1035 terminated with a zero unless the length is greater than comm_max. When any 1036 of extra, name, or comment are not NULL and the respective field is not 1037 present in the header, then that field is set to NULL to signal its 1038 absence. This allows the use of deflateSetHeader() with the returned 1039 structure to duplicate the header. However if those fields are set to 1040 allocated memory, then the application will need to save those pointers 1041 elsewhere so that they can be eventually freed. 1042 1043 If inflateGetHeader is not used, then the header information is simply 1044 discarded. The header is always checked for validity, including the header 1045 CRC if present. inflateReset() will reset the process to discard the header 1046 information. The application would need to call inflateGetHeader() again to 1047 retrieve the header from the next gzip stream. 1048 1049 inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source 1050 stream state was inconsistent. 1051 */ 1052 1053 /* 1054 Z_EXTERN int Z_EXPORT inflateBackInit (z_stream *strm, int windowBits, unsigned char *window); 1055 1056 Initialize the internal stream state for decompression using inflateBack() 1057 calls. The fields zalloc, zfree and opaque in strm must be initialized 1058 before the call. If zalloc and zfree are NULL, then the default library- 1059 derived memory allocation routines are used. windowBits is the base two 1060 logarithm of the window size, in the range 8..15. window is a caller 1061 supplied buffer of that size. Except for special applications where it is 1062 assured that deflate was used with small window sizes, windowBits must be 15 1063 and a 32K byte window must be supplied to be able to decompress general 1064 deflate streams. 1065 1066 See inflateBack() for the usage of these routines. 1067 1068 inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of 1069 the parameters are invalid, Z_MEM_ERROR if the internal state could not be 1070 allocated, or Z_VERSION_ERROR if the version of the library does not match 1071 the version of the header file. 1072 */ 1073 1074 typedef uint32_t (*in_func) (void *, z_const unsigned char * *); 1075 typedef int (*out_func) (void *, unsigned char *, uint32_t); 1076 1077 Z_EXTERN int Z_EXPORT inflateBack(z_stream *strm, in_func in, void *in_desc, out_func out, void *out_desc); 1078 /* 1079 inflateBack() does a raw inflate with a single call using a call-back 1080 interface for input and output. This is potentially more efficient than 1081 inflate() for file i/o applications, in that it avoids copying between the 1082 output and the sliding window by simply making the window itself the output 1083 buffer. inflate() can be faster on modern CPUs when used with large 1084 buffers. inflateBack() trusts the application to not change the output 1085 buffer passed by the output function, at least until inflateBack() returns. 1086 1087 inflateBackInit() must be called first to allocate the internal state 1088 and to initialize the state with the user-provided window buffer. 1089 inflateBack() may then be used multiple times to inflate a complete, raw 1090 deflate stream with each call. inflateBackEnd() is then called to free the 1091 allocated state. 1092 1093 A raw deflate stream is one with no zlib or gzip header or trailer. 1094 This routine would normally be used in a utility that reads zip or gzip 1095 files and writes out uncompressed files. The utility would decode the 1096 header and process the trailer on its own, hence this routine expects only 1097 the raw deflate stream to decompress. This is different from the default 1098 behavior of inflate(), which expects a zlib header and trailer around the 1099 deflate stream. 1100 1101 inflateBack() uses two subroutines supplied by the caller that are then 1102 called by inflateBack() for input and output. inflateBack() calls those 1103 routines until it reads a complete deflate stream and writes out all of the 1104 uncompressed data, or until it encounters an error. The function's 1105 parameters and return types are defined above in the in_func and out_func 1106 typedefs. inflateBack() will call in(in_desc, &buf) which should return the 1107 number of bytes of provided input, and a pointer to that input in buf. If 1108 there is no input available, in() must return zero -- buf is ignored in that 1109 case -- and inflateBack() will return a buffer error. inflateBack() will 1110 call out(out_desc, buf, len) to write the uncompressed data buf[0..len-1]. 1111 out() should return zero on success, or non-zero on failure. If out() 1112 returns non-zero, inflateBack() will return with an error. Neither in() nor 1113 out() are permitted to change the contents of the window provided to 1114 inflateBackInit(), which is also the buffer that out() uses to write from. 1115 The length written by out() will be at most the window size. Any non-zero 1116 amount of input may be provided by in(). 1117 1118 For convenience, inflateBack() can be provided input on the first call by 1119 setting strm->next_in and strm->avail_in. If that input is exhausted, then 1120 in() will be called. Therefore strm->next_in must be initialized before 1121 calling inflateBack(). If strm->next_in is NULL, then in() will be called 1122 immediately for input. If strm->next_in is not NULL, then strm->avail_in 1123 must also be initialized, and then if strm->avail_in is not zero, input will 1124 initially be taken from strm->next_in[0 .. strm->avail_in - 1]. 1125 1126 The in_desc and out_desc parameters of inflateBack() is passed as the 1127 first parameter of in() and out() respectively when they are called. These 1128 descriptors can be optionally used to pass any information that the caller- 1129 supplied in() and out() functions need to do their job. 1130 1131 On return, inflateBack() will set strm->next_in and strm->avail_in to 1132 pass back any unused input that was provided by the last in() call. The 1133 return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR 1134 if in() or out() returned an error, Z_DATA_ERROR if there was a format error 1135 in the deflate stream (in which case strm->msg is set to indicate the nature 1136 of the error), or Z_STREAM_ERROR if the stream was not properly initialized. 1137 In the case of Z_BUF_ERROR, an input or output error can be distinguished 1138 using strm->next_in which will be NULL only if in() returned an error. If 1139 strm->next_in is not NULL, then the Z_BUF_ERROR was due to out() returning 1140 non-zero. (in() will always be called before out(), so strm->next_in is 1141 assured to be defined if out() returns non-zero.) Note that inflateBack() 1142 cannot return Z_OK. 1143 */ 1144 1145 Z_EXTERN int Z_EXPORT inflateBackEnd(z_stream *strm); 1146 /* 1147 All memory allocated by inflateBackInit() is freed. 1148 1149 inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream 1150 state was inconsistent. 1151 */ 1152 1153 Z_EXTERN unsigned long Z_EXPORT zlibCompileFlags(void); 1154 /* Return flags indicating compile-time options. 1155 1156 Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other: 1157 1.0: size of unsigned int 1158 3.2: size of unsigned long 1159 5.4: size of void * (pointer) 1160 7.6: size of z_off_t 1161 1162 Compiler, assembler, and debug options: 1163 8: ZLIB_DEBUG 1164 9: ASMV or ASMINF -- use ASM code 1165 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention 1166 11: 0 (reserved) 1167 1168 One-time table building (smaller code, but not thread-safe if true): 1169 12: BUILDFIXED -- build static block decoding tables when needed (not supported by zlib-ng) 1170 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed 1171 14,15: 0 (reserved) 1172 1173 Library content (indicates missing functionality): 1174 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking 1175 deflate code when not needed) 1176 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect 1177 and decode gzip streams (to avoid linking crc code) 1178 18-19: 0 (reserved) 1179 1180 Operation variations (changes in library functionality): 1181 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate 1182 21: FASTEST -- deflate algorithm with only one, lowest compression level 1183 22,23: 0 (reserved) 1184 1185 The sprintf variant used by gzprintf (zero is best): 1186 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format 1187 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure! 1188 26: 0 = returns value, 1 = void -- 1 means inferred string length returned 1189 1190 Remainder: 1191 27-31: 0 (reserved) 1192 */ 1193 1194 1195 #ifndef Z_SOLO 1196 1197 /* utility functions */ 1198 1199 /* 1200 The following utility functions are implemented on top of the basic 1201 stream-oriented functions. To simplify the interface, some default options 1202 are assumed (compression level and memory usage, standard memory allocation 1203 functions). The source code of these utility functions can be modified if 1204 you need special options. 1205 */ 1206 1207 Z_EXTERN int Z_EXPORT compress(unsigned char *dest, unsigned long *destLen, const unsigned char *source, unsigned long sourceLen); 1208 /* 1209 Compresses the source buffer into the destination buffer. sourceLen is 1210 the byte length of the source buffer. Upon entry, destLen is the total size 1211 of the destination buffer, which must be at least the value returned by 1212 compressBound(sourceLen). Upon exit, destLen is the actual size of the 1213 compressed data. compress() is equivalent to compress2() with a level 1214 parameter of Z_DEFAULT_COMPRESSION. 1215 1216 compress returns Z_OK if success, Z_MEM_ERROR if there was not 1217 enough memory, Z_BUF_ERROR if there was not enough room in the output 1218 buffer. 1219 */ 1220 1221 Z_EXTERN int Z_EXPORT compress2(unsigned char *dest, unsigned long *destLen, const unsigned char *source, 1222 unsigned long sourceLen, int level); 1223 /* 1224 Compresses the source buffer into the destination buffer. The level 1225 parameter has the same meaning as in deflateInit. sourceLen is the byte 1226 length of the source buffer. Upon entry, destLen is the total size of the 1227 destination buffer, which must be at least the value returned by 1228 compressBound(sourceLen). Upon exit, destLen is the actual size of the 1229 compressed data. 1230 1231 compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough 1232 memory, Z_BUF_ERROR if there was not enough room in the output buffer, 1233 Z_STREAM_ERROR if the level parameter is invalid. 1234 */ 1235 1236 Z_EXTERN unsigned long Z_EXPORT compressBound(unsigned long sourceLen); 1237 /* 1238 compressBound() returns an upper bound on the compressed size after 1239 compress() or compress2() on sourceLen bytes. It would be used before a 1240 compress() or compress2() call to allocate the destination buffer. 1241 */ 1242 1243 Z_EXTERN int Z_EXPORT uncompress(unsigned char *dest, unsigned long *destLen, const unsigned char *source, unsigned long sourceLen); 1244 /* 1245 Decompresses the source buffer into the destination buffer. sourceLen is 1246 the byte length of the source buffer. Upon entry, destLen is the total size 1247 of the destination buffer, which must be large enough to hold the entire 1248 uncompressed data. (The size of the uncompressed data must have been saved 1249 previously by the compressor and transmitted to the decompressor by some 1250 mechanism outside the scope of this compression library.) Upon exit, destLen 1251 is the actual size of the uncompressed data. 1252 1253 uncompress returns Z_OK if success, Z_MEM_ERROR if there was not 1254 enough memory, Z_BUF_ERROR if there was not enough room in the output 1255 buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete. In 1256 the case where there is not enough room, uncompress() will fill the output 1257 buffer with the uncompressed data up to that point. 1258 */ 1259 1260 1261 Z_EXTERN int Z_EXPORT uncompress2 (unsigned char *dest, unsigned long *destLen, 1262 const unsigned char *source, unsigned long *sourceLen); 1263 /* 1264 Same as uncompress, except that sourceLen is a pointer, where the 1265 length of the source is *sourceLen. On return, *sourceLen is the number of 1266 source bytes consumed. 1267 */ 1268 1269 1270 /* gzip file access functions */ 1271 1272 /* 1273 This library supports reading and writing files in gzip (.gz) format with 1274 an interface similar to that of stdio, using the functions that start with 1275 "gz". The gzip format is different from the zlib format. gzip is a gzip 1276 wrapper, documented in RFC 1952, wrapped around a deflate stream. 1277 */ 1278 1279 typedef struct gzFile_s *gzFile; /* semi-opaque gzip file descriptor */ 1280 1281 /* 1282 Z_EXTERN gzFile Z_EXPORT gzopen(const char *path, const char *mode); 1283 1284 Open the gzip (.gz) file at path for reading and decompressing, or 1285 compressing and writing. The mode parameter is as in fopen ("rb" or "wb") 1286 but can also include a compression level ("wb9") or a strategy: 'f' for 1287 filtered data as in "wb6f", 'h' for Huffman-only compression as in "wb1h", 1288 'R' for run-length encoding as in "wb1R", or 'F' for fixed code compression 1289 as in "wb9F". (See the description of deflateInit2 for more information 1290 about the strategy parameter.) 'T' will request transparent writing or 1291 appending with no compression and not using the gzip format. 1292 1293 "a" can be used instead of "w" to request that the gzip stream that will 1294 be written be appended to the file. "+" will result in an error, since 1295 reading and writing to the same gzip file is not supported. The addition of 1296 "x" when writing will create the file exclusively, which fails if the file 1297 already exists. On systems that support it, the addition of "e" when 1298 reading or writing will set the flag to close the file on an execve() call. 1299 1300 These functions, as well as gzip, will read and decode a sequence of gzip 1301 streams in a file. The append function of gzopen() can be used to create 1302 such a file. (Also see gzflush() for another way to do this.) When 1303 appending, gzopen does not test whether the file begins with a gzip stream, 1304 nor does it look for the end of the gzip streams to begin appending. gzopen 1305 will simply append a gzip stream to the existing file. 1306 1307 gzopen can be used to read a file which is not in gzip format; in this 1308 case gzread will directly read from the file without decompression. When 1309 reading, this will be detected automatically by looking for the magic two- 1310 byte gzip header. 1311 1312 gzopen returns NULL if the file could not be opened, if there was 1313 insufficient memory to allocate the gzFile state, or if an invalid mode was 1314 specified (an 'r', 'w', or 'a' was not provided, or '+' was provided). 1315 errno can be checked to determine if the reason gzopen failed was that the 1316 file could not be opened. 1317 */ 1318 1319 Z_EXTERN gzFile Z_EXPORT gzdopen(int fd, const char *mode); 1320 /* 1321 Associate a gzFile with the file descriptor fd. File descriptors are 1322 obtained from calls like open, dup, creat, pipe or fileno (if the file has 1323 been previously opened with fopen). The mode parameter is as in gzopen. 1324 1325 The next call of gzclose on the returned gzFile will also close the file 1326 descriptor fd, just like fclose(fdopen(fd, mode)) closes the file descriptor 1327 fd. If you want to keep fd open, use fd = dup(fd_keep); gz = gzdopen(fd, 1328 mode);. The duplicated descriptor should be saved to avoid a leak, since 1329 gzdopen does not close fd if it fails. If you are using fileno() to get the 1330 file descriptor from a FILE *, then you will have to use dup() to avoid 1331 double-close()ing the file descriptor. Both gzclose() and fclose() will 1332 close the associated file descriptor, so they need to have different file 1333 descriptors. 1334 1335 gzdopen returns NULL if there was insufficient memory to allocate the 1336 gzFile state, if an invalid mode was specified (an 'r', 'w', or 'a' was not 1337 provided, or '+' was provided), or if fd is -1. The file descriptor is not 1338 used until the next gz* read, write, seek, or close operation, so gzdopen 1339 will not detect if fd is invalid (unless fd is -1). 1340 */ 1341 1342 Z_EXTERN int Z_EXPORT gzbuffer(gzFile file, unsigned size); 1343 /* 1344 Set the internal buffer size used by this library's functions for file to 1345 size. The default buffer size is 8192 bytes. This function must be called 1346 after gzopen() or gzdopen(), and before any other calls that read or write 1347 the file. The buffer memory allocation is always deferred to the first read 1348 or write. Three times that size in buffer space is allocated. A larger 1349 buffer size of, for example, 64K or 128K bytes will noticeably increase the 1350 speed of decompression (reading). 1351 1352 The new buffer size also affects the maximum length for gzprintf(). 1353 1354 gzbuffer() returns 0 on success, or -1 on failure, such as being called 1355 too late. 1356 */ 1357 1358 Z_EXTERN int Z_EXPORT gzsetparams(gzFile file, int level, int strategy); 1359 /* 1360 Dynamically update the compression level and strategy for file. See the 1361 description of deflateInit2 for the meaning of these parameters. Previously 1362 provided data is flushed before applying the parameter changes. 1363 1364 gzsetparams returns Z_OK if success, Z_STREAM_ERROR if the file was not 1365 opened for writing, Z_ERRNO if there is an error writing the flushed data, 1366 or Z_MEM_ERROR if there is a memory allocation error. 1367 */ 1368 1369 Z_EXTERN int Z_EXPORT gzread(gzFile file, void *buf, unsigned len); 1370 /* 1371 Read and decompress up to len uncompressed bytes from file into buf. If 1372 the input file is not in gzip format, gzread copies the given number of 1373 bytes into the buffer directly from the file. 1374 1375 After reaching the end of a gzip stream in the input, gzread will continue 1376 to read, looking for another gzip stream. Any number of gzip streams may be 1377 concatenated in the input file, and will all be decompressed by gzread(). 1378 If something other than a gzip stream is encountered after a gzip stream, 1379 that remaining trailing garbage is ignored (and no error is returned). 1380 1381 gzread can be used to read a gzip file that is being concurrently written. 1382 Upon reaching the end of the input, gzread will return with the available 1383 data. If the error code returned by gzerror is Z_OK or Z_BUF_ERROR, then 1384 gzclearerr can be used to clear the end of file indicator in order to permit 1385 gzread to be tried again. Z_OK indicates that a gzip stream was completed 1386 on the last gzread. Z_BUF_ERROR indicates that the input file ended in the 1387 middle of a gzip stream. Note that gzread does not return -1 in the event 1388 of an incomplete gzip stream. This error is deferred until gzclose(), which 1389 will return Z_BUF_ERROR if the last gzread ended in the middle of a gzip 1390 stream. Alternatively, gzerror can be used before gzclose to detect this 1391 case. 1392 1393 gzread returns the number of uncompressed bytes actually read, less than 1394 len for end of file, or -1 for error. If len is too large to fit in an int, 1395 then nothing is read, -1 is returned, and the error state is set to 1396 Z_STREAM_ERROR. 1397 */ 1398 1399 Z_EXTERN size_t Z_EXPORT gzfread (void *buf, size_t size, size_t nitems, gzFile file); 1400 /* 1401 Read and decompress up to nitems items of size size from file into buf, 1402 otherwise operating as gzread() does. This duplicates the interface of 1403 stdio's fread(), with size_t request and return types. If the library 1404 defines size_t, then z_size_t is identical to size_t. If not, then z_size_t 1405 is an unsigned integer type that can contain a pointer. 1406 1407 gzfread() returns the number of full items read of size size, or zero if 1408 the end of the file was reached and a full item could not be read, or if 1409 there was an error. gzerror() must be consulted if zero is returned in 1410 order to determine if there was an error. If the multiplication of size and 1411 nitems overflows, i.e. the product does not fit in a size_t, then nothing 1412 is read, zero is returned, and the error state is set to Z_STREAM_ERROR. 1413 1414 In the event that the end of file is reached and only a partial item is 1415 available at the end, i.e. the remaining uncompressed data length is not a 1416 multiple of size, then the final partial item is nevertheless read into buf 1417 and the end-of-file flag is set. The length of the partial item read is not 1418 provided, but could be inferred from the result of gztell(). This behavior 1419 is the same as the behavior of fread() implementations in common libraries, 1420 but it prevents the direct use of gzfread() to read a concurrently written 1421 file, resetting and retrying on end-of-file, when size is not 1. 1422 */ 1423 1424 Z_EXTERN int Z_EXPORT gzwrite(gzFile file, void const *buf, unsigned len); 1425 /* 1426 Compress and write the len uncompressed bytes at buf to file. gzwrite 1427 returns the number of uncompressed bytes written or 0 in case of error. 1428 */ 1429 1430 Z_EXTERN size_t Z_EXPORT gzfwrite(void const *buf, size_t size, size_t nitems, gzFile file); 1431 /* 1432 Compress and write nitems items of size size from buf to file, duplicating 1433 the interface of stdio's fwrite(), with size_t request and return types. 1434 1435 gzfwrite() returns the number of full items written of size size, or zero 1436 if there was an error. If the multiplication of size and nitems overflows, 1437 i.e. the product does not fit in a size_t, then nothing is written, zero 1438 is returned, and the error state is set to Z_STREAM_ERROR. 1439 */ 1440 1441 Z_EXTERN int Z_EXPORTVA gzprintf(gzFile file, const char *format, ...); 1442 /* 1443 Convert, format, compress, and write the arguments (...) to file under 1444 control of the string format, as in fprintf. gzprintf returns the number of 1445 uncompressed bytes actually written, or a negative zlib error code in case 1446 of error. The number of uncompressed bytes written is limited to 8191, or 1447 one less than the buffer size given to gzbuffer(). The caller should assure 1448 that this limit is not exceeded. If it is exceeded, then gzprintf() will 1449 return an error (0) with nothing written. In this case, there may also be a 1450 buffer overflow with unpredictable consequences, which is possible only if 1451 zlib was compiled with the insecure functions sprintf() or vsprintf(), 1452 because the secure snprintf() or vsnprintf() functions were not available. 1453 This can be determined using zlibCompileFlags(). 1454 */ 1455 1456 Z_EXTERN int Z_EXPORT gzputs(gzFile file, const char *s); 1457 /* 1458 Compress and write the given null-terminated string s to file, excluding 1459 the terminating null character. 1460 1461 gzputs returns the number of characters written, or -1 in case of error. 1462 */ 1463 1464 Z_EXTERN char * Z_EXPORT gzgets(gzFile file, char *buf, int len); 1465 /* 1466 Read and decompress bytes from file into buf, until len-1 characters are 1467 read, or until a newline character is read and transferred to buf, or an 1468 end-of-file condition is encountered. If any characters are read or if len 1469 is one, the string is terminated with a null character. If no characters 1470 are read due to an end-of-file or len is less than one, then the buffer is 1471 left untouched. 1472 1473 gzgets returns buf which is a null-terminated string, or it returns NULL 1474 for end-of-file or in case of error. If there was an error, the contents at 1475 buf are indeterminate. 1476 */ 1477 1478 Z_EXTERN int Z_EXPORT gzputc(gzFile file, int c); 1479 /* 1480 Compress and write c, converted to an unsigned char, into file. gzputc 1481 returns the value that was written, or -1 in case of error. 1482 */ 1483 1484 Z_EXTERN int Z_EXPORT gzgetc(gzFile file); 1485 /* 1486 Read and decompress one byte from file. gzgetc returns this byte or -1 1487 in case of end of file or error. This is implemented as a macro for speed. 1488 As such, it does not do all of the checking the other functions do. I.e. 1489 it does not check to see if file is NULL, nor whether the structure file 1490 points to has been clobbered or not. 1491 */ 1492 1493 Z_EXTERN int Z_EXPORT gzungetc(int c, gzFile file); 1494 /* 1495 Push c back onto the stream for file to be read as the first character on 1496 the next read. At least one character of push-back is always allowed. 1497 gzungetc() returns the character pushed, or -1 on failure. gzungetc() will 1498 fail if c is -1, and may fail if a character has been pushed but not read 1499 yet. If gzungetc is used immediately after gzopen or gzdopen, at least the 1500 output buffer size of pushed characters is allowed. (See gzbuffer above.) 1501 The pushed character will be discarded if the stream is repositioned with 1502 gzseek() or gzrewind(). 1503 */ 1504 1505 Z_EXTERN int Z_EXPORT gzflush(gzFile file, int flush); 1506 /* 1507 Flush all pending output to file. The parameter flush is as in the 1508 deflate() function. The return value is the zlib error number (see function 1509 gzerror below). gzflush is only permitted when writing. 1510 1511 If the flush parameter is Z_FINISH, the remaining data is written and the 1512 gzip stream is completed in the output. If gzwrite() is called again, a new 1513 gzip stream will be started in the output. gzread() is able to read such 1514 concatenated gzip streams. 1515 1516 gzflush should be called only when strictly necessary because it will 1517 degrade compression if called too often. 1518 */ 1519 1520 /* 1521 Z_EXTERN z_off_t Z_EXPORT gzseek (gzFile file, z_off_t offset, int whence); 1522 1523 Set the starting position to offset relative to whence for the next gzread 1524 or gzwrite on file. The offset represents a number of bytes in the 1525 uncompressed data stream. The whence parameter is defined as in lseek(2); 1526 the value SEEK_END is not supported. 1527 1528 If the file is opened for reading, this function is emulated but can be 1529 extremely slow. If the file is opened for writing, only forward seeks are 1530 supported; gzseek then compresses a sequence of zeroes up to the new 1531 starting position. 1532 1533 gzseek returns the resulting offset location as measured in bytes from 1534 the beginning of the uncompressed stream, or -1 in case of error, in 1535 particular if the file is opened for writing and the new starting position 1536 would be before the current position. 1537 */ 1538 1539 Z_EXTERN int Z_EXPORT gzrewind(gzFile file); 1540 /* 1541 Rewind file. This function is supported only for reading. 1542 1543 gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET). 1544 */ 1545 1546 /* 1547 Z_EXTERN z_off_t Z_EXPORT gztell(gzFile file); 1548 1549 Return the starting position for the next gzread or gzwrite on file. 1550 This position represents a number of bytes in the uncompressed data stream, 1551 and is zero when starting, even if appending or reading a gzip stream from 1552 the middle of a file using gzdopen(). 1553 1554 gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR) 1555 */ 1556 1557 /* 1558 Z_EXTERN z_off_t Z_EXPORT gzoffset(gzFile file); 1559 1560 Return the current compressed (actual) read or write offset of file. This 1561 offset includes the count of bytes that precede the gzip stream, for example 1562 when appending or when using gzdopen() for reading. When reading, the 1563 offset does not include as yet unused buffered input. This information can 1564 be used for a progress indicator. On error, gzoffset() returns -1. 1565 */ 1566 1567 Z_EXTERN int Z_EXPORT gzeof(gzFile file); 1568 /* 1569 Return true (1) if the end-of-file indicator for file has been set while 1570 reading, false (0) otherwise. Note that the end-of-file indicator is set 1571 only if the read tried to go past the end of the input, but came up short. 1572 Therefore, just like feof(), gzeof() may return false even if there is no 1573 more data to read, in the event that the last read request was for the exact 1574 number of bytes remaining in the input file. This will happen if the input 1575 file size is an exact multiple of the buffer size. 1576 1577 If gzeof() returns true, then the read functions will return no more data, 1578 unless the end-of-file indicator is reset by gzclearerr() and the input file 1579 has grown since the previous end of file was detected. 1580 */ 1581 1582 Z_EXTERN int Z_EXPORT gzdirect(gzFile file); 1583 /* 1584 Return true (1) if file is being copied directly while reading, or false 1585 (0) if file is a gzip stream being decompressed. 1586 1587 If the input file is empty, gzdirect() will return true, since the input 1588 does not contain a gzip stream. 1589 1590 If gzdirect() is used immediately after gzopen() or gzdopen() it will 1591 cause buffers to be allocated to allow reading the file to determine if it 1592 is a gzip file. Therefore if gzbuffer() is used, it should be called before 1593 gzdirect(). 1594 1595 When writing, gzdirect() returns true (1) if transparent writing was 1596 requested ("wT" for the gzopen() mode), or false (0) otherwise. (Note: 1597 gzdirect() is not needed when writing. Transparent writing must be 1598 explicitly requested, so the application already knows the answer. When 1599 linking statically, using gzdirect() will include all of the zlib code for 1600 gzip file reading and decompression, which may not be desired.) 1601 */ 1602 1603 Z_EXTERN int Z_EXPORT gzclose(gzFile file); 1604 /* 1605 Flush all pending output for file, if necessary, close file and 1606 deallocate the (de)compression state. Note that once file is closed, you 1607 cannot call gzerror with file, since its structures have been deallocated. 1608 gzclose must not be called more than once on the same file, just as free 1609 must not be called more than once on the same allocation. 1610 1611 gzclose will return Z_STREAM_ERROR if file is not valid, Z_ERRNO on a 1612 file operation error, Z_MEM_ERROR if out of memory, Z_BUF_ERROR if the 1613 last read ended in the middle of a gzip stream, or Z_OK on success. 1614 */ 1615 1616 Z_EXTERN int Z_EXPORT gzclose_r(gzFile file); 1617 Z_EXTERN int Z_EXPORT gzclose_w(gzFile file); 1618 /* 1619 Same as gzclose(), but gzclose_r() is only for use when reading, and 1620 gzclose_w() is only for use when writing or appending. The advantage to 1621 using these instead of gzclose() is that they avoid linking in zlib 1622 compression or decompression code that is not used when only reading or only 1623 writing respectively. If gzclose() is used, then both compression and 1624 decompression code will be included the application when linking to a static 1625 zlib library. 1626 */ 1627 1628 Z_EXTERN const char * Z_EXPORT gzerror(gzFile file, int *errnum); 1629 /* 1630 Return the error message for the last error which occurred on file. 1631 errnum is set to zlib error number. If an error occurred in the file system 1632 and not in the compression library, errnum is set to Z_ERRNO and the 1633 application may consult errno to get the exact error code. 1634 1635 The application must not modify the returned string. Future calls to 1636 this function may invalidate the previously returned string. If file is 1637 closed, then the string previously returned by gzerror will no longer be 1638 available. 1639 1640 gzerror() should be used to distinguish errors from end-of-file for those 1641 functions above that do not distinguish those cases in their return values. 1642 */ 1643 1644 Z_EXTERN void Z_EXPORT gzclearerr(gzFile file); 1645 /* 1646 Clear the error and end-of-file flags for file. This is analogous to the 1647 clearerr() function in stdio. This is useful for continuing to read a gzip 1648 file that is being written concurrently. 1649 */ 1650 1651 #endif 1652 1653 /* checksum functions */ 1654 1655 /* 1656 These functions are not related to compression but are exported 1657 anyway because they might be useful in applications using the compression 1658 library. 1659 */ 1660 1661 Z_EXTERN unsigned long Z_EXPORT adler32(unsigned long adler, const unsigned char *buf, unsigned int len); 1662 /* 1663 Update a running Adler-32 checksum with the bytes buf[0..len-1] and 1664 return the updated checksum. An Adler-32 value is in the range of a 32-bit 1665 unsigned integer. If buf is Z_NULL, this function returns the required 1666 initial value for the checksum. 1667 1668 An Adler-32 checksum is almost as reliable as a CRC-32 but can be computed 1669 much faster. 1670 1671 Usage example: 1672 1673 uint32_t adler = adler32(0L, NULL, 0); 1674 1675 while (read_buffer(buffer, length) != EOF) { 1676 adler = adler32(adler, buffer, length); 1677 } 1678 if (adler != original_adler) error(); 1679 */ 1680 1681 Z_EXTERN unsigned long Z_EXPORT adler32_z(unsigned long adler, const unsigned char *buf, size_t len); 1682 /* 1683 Same as adler32(), but with a size_t length. 1684 */ 1685 1686 /* 1687 Z_EXTERN unsigned long Z_EXPORT adler32_combine(unsigned long adler1, unsigned long adler2, z_off_t len2); 1688 1689 Combine two Adler-32 checksums into one. For two sequences of bytes, seq1 1690 and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for 1691 each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of 1692 seq1 and seq2 concatenated, requiring only adler1, adler2, and len2. Note 1693 that the z_off_t type (like off_t) is a signed integer. If len2 is 1694 negative, the result has no meaning or utility. 1695 */ 1696 1697 Z_EXTERN unsigned long Z_EXPORT crc32(unsigned long crc, const unsigned char *buf, unsigned int len); 1698 /* 1699 Update a running CRC-32 with the bytes buf[0..len-1] and return the 1700 updated CRC-32. A CRC-32 value is in the range of a 32-bit unsigned integer. 1701 If buf is Z_NULL, this function returns the required initial value for the 1702 crc. Pre- and post-conditioning (one's complement) is performed within this 1703 function so it shouldn't be done by the application. 1704 1705 Usage example: 1706 1707 uint32_t crc = crc32(0L, NULL, 0); 1708 1709 while (read_buffer(buffer, length) != EOF) { 1710 crc = crc32(crc, buffer, length); 1711 } 1712 if (crc != original_crc) error(); 1713 */ 1714 1715 Z_EXTERN unsigned long Z_EXPORT crc32_z(unsigned long crc, const unsigned char *buf, size_t len); 1716 /* 1717 Same as crc32(), but with a size_t length. 1718 */ 1719 1720 /* 1721 Z_EXTERN unsigned long Z_EXPORT crc32_combine(unsigned long crc1, unsigned long crc2, z_off64_t len2); 1722 1723 Combine two CRC-32 check values into one. For two sequences of bytes, 1724 seq1 and seq2 with lengths len1 and len2, CRC-32 check values were 1725 calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32 1726 check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and 1727 len2. 1728 */ 1729 1730 /* 1731 Z_EXTERN void Z_EXPORT crc32_combine_gen(uint32_t op[32], z_off_t len2); 1732 1733 Generate the operator op corresponding to length len2, to be used with 1734 crc32_combine_op(). op must have room for 32 z_crc_t values. (32 is the 1735 number of bits in the CRC.) 1736 */ 1737 1738 Z_EXTERN uint32_t Z_EXPORT crc32_combine_op(uint32_t crc1, uint32_t crc2, 1739 const uint32_t *op); 1740 /* 1741 Give the same result as crc32_combine(), using op in place of len2. op is 1742 is generated from len2 by crc32_combine_gen(). This will be faster than 1743 crc32_combine() if the generated op is used many times. 1744 */ 1745 1746 1747 /* various hacks, don't look :) */ 1748 1749 /* deflateInit and inflateInit are macros to allow checking the zlib version 1750 * and the compiler's view of z_stream: 1751 */ 1752 Z_EXTERN int Z_EXPORT deflateInit_(z_stream *strm, int level, const char *version, int stream_size); 1753 Z_EXTERN int Z_EXPORT inflateInit_(z_stream *strm, const char *version, int stream_size); 1754 Z_EXTERN int Z_EXPORT deflateInit2_(z_stream *strm, int level, int method, int windowBits, int memLevel, 1755 int strategy, const char *version, int stream_size); 1756 Z_EXTERN int Z_EXPORT inflateInit2_(z_stream *strm, int windowBits, const char *version, int stream_size); 1757 Z_EXTERN int Z_EXPORT inflateBackInit_(z_stream *strm, int windowBits, unsigned char *window, 1758 const char *version, int stream_size); 1759 #define deflateInit(strm, level) deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream)) 1760 #define inflateInit(strm) inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream)) 1761 #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \ 1762 deflateInit2_((strm), (level), (method), (windowBits), (memLevel), \ 1763 (strategy), ZLIB_VERSION, (int)sizeof(z_stream)) 1764 #define inflateInit2(strm, windowBits) inflateInit2_((strm), (windowBits), ZLIB_VERSION, (int)sizeof(z_stream)) 1765 #define inflateBackInit(strm, windowBits, window) \ 1766 inflateBackInit_((strm), (windowBits), (window), ZLIB_VERSION, (int)sizeof(z_stream)) 1767 1768 1769 /* gzgetc() macro and its supporting function and exposed data structure. Note 1770 * that the real internal state is much larger than the exposed structure. 1771 * This abbreviated structure exposes just enough for the gzgetc() macro. The 1772 * user should not mess with these exposed elements, since their names or 1773 * behavior could change in the future, perhaps even capriciously. They can 1774 * only be used by the gzgetc() macro. You have been warned. 1775 */ 1776 struct gzFile_s { 1777 unsigned have; 1778 unsigned char *next; 1779 z_off64_t pos; 1780 }; 1781 Z_EXTERN int Z_EXPORT gzgetc_(gzFile file); /* backward compatibility */ 1782 # define gzgetc(g) ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : (gzgetc)(g)) 1783 1784 /* provide 64-bit offset functions if _LARGEFILE64_SOURCE defined, and/or 1785 * change the regular functions to 64 bits if _FILE_OFFSET_BITS is 64 (if 1786 * both are true, the application gets the *64 functions, and the regular 1787 * functions are changed to 64 bits) -- in case these are set on systems 1788 * without large file support, _LFS64_LARGEFILE must also be true 1789 */ 1790 #ifdef Z_LARGE64 1791 Z_EXTERN gzFile Z_EXPORT gzopen64(const char *, const char *); 1792 Z_EXTERN z_off64_t Z_EXPORT gzseek64(gzFile, z_off64_t, int); 1793 Z_EXTERN z_off64_t Z_EXPORT gztell64(gzFile); 1794 Z_EXTERN z_off64_t Z_EXPORT gzoffset64(gzFile); 1795 Z_EXTERN unsigned long Z_EXPORT adler32_combine64(unsigned long, unsigned long, z_off64_t); 1796 Z_EXTERN unsigned long Z_EXPORT crc32_combine64(unsigned long, unsigned long, z_off64_t); 1797 Z_EXTERN void Z_EXPORT crc32_combine_gen64(uint32_t *op, z_off64_t); 1798 #endif 1799 1800 #if !defined(Z_INTERNAL) && defined(Z_WANT64) 1801 # define gzopen gzopen64 1802 # define gzseek gzseek64 1803 # define gztell gztell64 1804 # define gzoffset gzoffset64 1805 # define adler32_combine adler32_combine64 1806 # define crc32_combine crc32_combine64 1807 # define crc32_combine_gen crc32_combine_gen64 1808 # ifndef Z_LARGE64 1809 Z_EXTERN gzFile Z_EXPORT gzopen64(const char *, const char *); 1810 Z_EXTERN z_off_t Z_EXPORT gzseek64(gzFile, z_off_t, int); 1811 Z_EXTERN z_off_t Z_EXPORT gztell64(gzFile); 1812 Z_EXTERN z_off_t Z_EXPORT gzoffset64(gzFile); 1813 Z_EXTERN unsigned long Z_EXPORT adler32_combine64(unsigned long, unsigned long, z_off_t); 1814 Z_EXTERN unsigned long Z_EXPORT crc32_combine64(unsigned long, unsigned long, z_off_t); 1815 Z_EXTERN void Z_EXPORT crc32_combine_gen64(uint32_t *op, z_off64_t); 1816 # endif 1817 #else 1818 Z_EXTERN gzFile Z_EXPORT gzopen(const char *, const char *); 1819 Z_EXTERN z_off_t Z_EXPORT gzseek(gzFile, z_off_t, int); 1820 Z_EXTERN z_off_t Z_EXPORT gztell(gzFile); 1821 Z_EXTERN z_off_t Z_EXPORT gzoffset(gzFile); 1822 Z_EXTERN unsigned long Z_EXPORT adler32_combine(unsigned long, unsigned long, z_off_t); 1823 Z_EXTERN unsigned long Z_EXPORT crc32_combine(unsigned long, unsigned long, z_off_t); 1824 Z_EXTERN void Z_EXPORT crc32_combine_gen(uint32_t *op, z_off_t); 1825 #endif 1826 1827 /* undocumented functions */ 1828 Z_EXTERN const char * Z_EXPORT zError (int); 1829 Z_EXTERN int Z_EXPORT inflateSyncPoint (z_stream *); 1830 Z_EXTERN const uint32_t * Z_EXPORT get_crc_table (void); 1831 Z_EXTERN int Z_EXPORT inflateUndermine (z_stream *, int); 1832 Z_EXTERN int Z_EXPORT inflateValidate (z_stream *, int); 1833 Z_EXTERN unsigned long Z_EXPORT inflateCodesUsed (z_stream *); 1834 Z_EXTERN int Z_EXPORT inflateResetKeep (z_stream *); 1835 Z_EXTERN int Z_EXPORT deflateResetKeep (z_stream *); 1836 1837 #if defined(_WIN32) 1838 Z_EXTERN gzFile Z_EXPORT gzopen_w(const wchar_t *path, const char *mode); 1839 #endif 1840 Z_EXTERN int Z_EXPORTVA gzvprintf(gzFile file, const char *format, va_list va); 1841 1842 #ifdef __cplusplus 1843 } 1844 #endif 1845 1846 #endif /* ZLIB_H_ */ 1847