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annotate libs/zlib/zlib.h @ 13:ea928c313344

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author John Tsiombikas <nuclear@member.fsf.org>
date Mon, 28 Sep 2015 19:04:50 +0300
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nuclear@2 1 /* zlib.h -- interface of the 'zlib' general purpose compression library
nuclear@2 2 version 1.2.3, July 18th, 2005
nuclear@2 3
nuclear@2 4 Copyright (C) 1995-2005 Jean-loup Gailly and Mark Adler
nuclear@2 5
nuclear@2 6 This software is provided 'as-is', without any express or implied
nuclear@2 7 warranty. In no event will the authors be held liable for any damages
nuclear@2 8 arising from the use of this software.
nuclear@2 9
nuclear@2 10 Permission is granted to anyone to use this software for any purpose,
nuclear@2 11 including commercial applications, and to alter it and redistribute it
nuclear@2 12 freely, subject to the following restrictions:
nuclear@2 13
nuclear@2 14 1. The origin of this software must not be misrepresented; you must not
nuclear@2 15 claim that you wrote the original software. If you use this software
nuclear@2 16 in a product, an acknowledgment in the product documentation would be
nuclear@2 17 appreciated but is not required.
nuclear@2 18 2. Altered source versions must be plainly marked as such, and must not be
nuclear@2 19 misrepresented as being the original software.
nuclear@2 20 3. This notice may not be removed or altered from any source distribution.
nuclear@2 21
nuclear@2 22 Jean-loup Gailly Mark Adler
nuclear@2 23 jloup@gzip.org madler@alumni.caltech.edu
nuclear@2 24
nuclear@2 25
nuclear@2 26 The data format used by the zlib library is described by RFCs (Request for
nuclear@2 27 Comments) 1950 to 1952 in the files http://www.ietf.org/rfc/rfc1950.txt
nuclear@2 28 (zlib format), rfc1951.txt (deflate format) and rfc1952.txt (gzip format).
nuclear@2 29 */
nuclear@2 30
nuclear@2 31 #ifndef ZLIB_H
nuclear@2 32 #define ZLIB_H
nuclear@2 33
nuclear@2 34 #include "zconf.h"
nuclear@2 35
nuclear@2 36 #ifdef __cplusplus
nuclear@2 37 extern "C" {
nuclear@2 38 #endif
nuclear@2 39
nuclear@2 40 #define ZLIB_VERSION "1.2.3"
nuclear@2 41 #define ZLIB_VERNUM 0x1230
nuclear@2 42
nuclear@2 43 /*
nuclear@2 44 The 'zlib' compression library provides in-memory compression and
nuclear@2 45 decompression functions, including integrity checks of the uncompressed
nuclear@2 46 data. This version of the library supports only one compression method
nuclear@2 47 (deflation) but other algorithms will be added later and will have the same
nuclear@2 48 stream interface.
nuclear@2 49
nuclear@2 50 Compression can be done in a single step if the buffers are large
nuclear@2 51 enough (for example if an input file is mmap'ed), or can be done by
nuclear@2 52 repeated calls of the compression function. In the latter case, the
nuclear@2 53 application must provide more input and/or consume the output
nuclear@2 54 (providing more output space) before each call.
nuclear@2 55
nuclear@2 56 The compressed data format used by default by the in-memory functions is
nuclear@2 57 the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped
nuclear@2 58 around a deflate stream, which is itself documented in RFC 1951.
nuclear@2 59
nuclear@2 60 The library also supports reading and writing files in gzip (.gz) format
nuclear@2 61 with an interface similar to that of stdio using the functions that start
nuclear@2 62 with "gz". The gzip format is different from the zlib format. gzip is a
nuclear@2 63 gzip wrapper, documented in RFC 1952, wrapped around a deflate stream.
nuclear@2 64
nuclear@2 65 This library can optionally read and write gzip streams in memory as well.
nuclear@2 66
nuclear@2 67 The zlib format was designed to be compact and fast for use in memory
nuclear@2 68 and on communications channels. The gzip format was designed for single-
nuclear@2 69 file compression on file systems, has a larger header than zlib to maintain
nuclear@2 70 directory information, and uses a different, slower check method than zlib.
nuclear@2 71
nuclear@2 72 The library does not install any signal handler. The decoder checks
nuclear@2 73 the consistency of the compressed data, so the library should never
nuclear@2 74 crash even in case of corrupted input.
nuclear@2 75 */
nuclear@2 76
nuclear@2 77 typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size));
nuclear@2 78 typedef void (*free_func) OF((voidpf opaque, voidpf address));
nuclear@2 79
nuclear@2 80 struct internal_state;
nuclear@2 81
nuclear@2 82 typedef struct z_stream_s {
nuclear@2 83 Bytef *next_in; /* next input byte */
nuclear@2 84 uInt avail_in; /* number of bytes available at next_in */
nuclear@2 85 uLong total_in; /* total nb of input bytes read so far */
nuclear@2 86
nuclear@2 87 Bytef *next_out; /* next output byte should be put there */
nuclear@2 88 uInt avail_out; /* remaining free space at next_out */
nuclear@2 89 uLong total_out; /* total nb of bytes output so far */
nuclear@2 90
nuclear@2 91 char *msg; /* last error message, NULL if no error */
nuclear@2 92 struct internal_state FAR *state; /* not visible by applications */
nuclear@2 93
nuclear@2 94 alloc_func zalloc; /* used to allocate the internal state */
nuclear@2 95 free_func zfree; /* used to free the internal state */
nuclear@2 96 voidpf opaque; /* private data object passed to zalloc and zfree */
nuclear@2 97
nuclear@2 98 int data_type; /* best guess about the data type: binary or text */
nuclear@2 99 uLong adler; /* adler32 value of the uncompressed data */
nuclear@2 100 uLong reserved; /* reserved for future use */
nuclear@2 101 } z_stream;
nuclear@2 102
nuclear@2 103 typedef z_stream FAR *z_streamp;
nuclear@2 104
nuclear@2 105 /*
nuclear@2 106 gzip header information passed to and from zlib routines. See RFC 1952
nuclear@2 107 for more details on the meanings of these fields.
nuclear@2 108 */
nuclear@2 109 typedef struct gz_header_s {
nuclear@2 110 int text; /* true if compressed data believed to be text */
nuclear@2 111 uLong time; /* modification time */
nuclear@2 112 int xflags; /* extra flags (not used when writing a gzip file) */
nuclear@2 113 int os; /* operating system */
nuclear@2 114 Bytef *extra; /* pointer to extra field or Z_NULL if none */
nuclear@2 115 uInt extra_len; /* extra field length (valid if extra != Z_NULL) */
nuclear@2 116 uInt extra_max; /* space at extra (only when reading header) */
nuclear@2 117 Bytef *name; /* pointer to zero-terminated file name or Z_NULL */
nuclear@2 118 uInt name_max; /* space at name (only when reading header) */
nuclear@2 119 Bytef *comment; /* pointer to zero-terminated comment or Z_NULL */
nuclear@2 120 uInt comm_max; /* space at comment (only when reading header) */
nuclear@2 121 int hcrc; /* true if there was or will be a header crc */
nuclear@2 122 int done; /* true when done reading gzip header (not used
nuclear@2 123 when writing a gzip file) */
nuclear@2 124 } gz_header;
nuclear@2 125
nuclear@2 126 typedef gz_header FAR *gz_headerp;
nuclear@2 127
nuclear@2 128 /*
nuclear@2 129 The application must update next_in and avail_in when avail_in has
nuclear@2 130 dropped to zero. It must update next_out and avail_out when avail_out
nuclear@2 131 has dropped to zero. The application must initialize zalloc, zfree and
nuclear@2 132 opaque before calling the init function. All other fields are set by the
nuclear@2 133 compression library and must not be updated by the application.
nuclear@2 134
nuclear@2 135 The opaque value provided by the application will be passed as the first
nuclear@2 136 parameter for calls of zalloc and zfree. This can be useful for custom
nuclear@2 137 memory management. The compression library attaches no meaning to the
nuclear@2 138 opaque value.
nuclear@2 139
nuclear@2 140 zalloc must return Z_NULL if there is not enough memory for the object.
nuclear@2 141 If zlib is used in a multi-threaded application, zalloc and zfree must be
nuclear@2 142 thread safe.
nuclear@2 143
nuclear@2 144 On 16-bit systems, the functions zalloc and zfree must be able to allocate
nuclear@2 145 exactly 65536 bytes, but will not be required to allocate more than this
nuclear@2 146 if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS,
nuclear@2 147 pointers returned by zalloc for objects of exactly 65536 bytes *must*
nuclear@2 148 have their offset normalized to zero. The default allocation function
nuclear@2 149 provided by this library ensures this (see zutil.c). To reduce memory
nuclear@2 150 requirements and avoid any allocation of 64K objects, at the expense of
nuclear@2 151 compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h).
nuclear@2 152
nuclear@2 153 The fields total_in and total_out can be used for statistics or
nuclear@2 154 progress reports. After compression, total_in holds the total size of
nuclear@2 155 the uncompressed data and may be saved for use in the decompressor
nuclear@2 156 (particularly if the decompressor wants to decompress everything in
nuclear@2 157 a single step).
nuclear@2 158 */
nuclear@2 159
nuclear@2 160 /* constants */
nuclear@2 161
nuclear@2 162 #define Z_NO_FLUSH 0
nuclear@2 163 #define Z_PARTIAL_FLUSH 1 /* will be removed, use Z_SYNC_FLUSH instead */
nuclear@2 164 #define Z_SYNC_FLUSH 2
nuclear@2 165 #define Z_FULL_FLUSH 3
nuclear@2 166 #define Z_FINISH 4
nuclear@2 167 #define Z_BLOCK 5
nuclear@2 168 /* Allowed flush values; see deflate() and inflate() below for details */
nuclear@2 169
nuclear@2 170 #define Z_OK 0
nuclear@2 171 #define Z_STREAM_END 1
nuclear@2 172 #define Z_NEED_DICT 2
nuclear@2 173 #define Z_ERRNO (-1)
nuclear@2 174 #define Z_STREAM_ERROR (-2)
nuclear@2 175 #define Z_DATA_ERROR (-3)
nuclear@2 176 #define Z_MEM_ERROR (-4)
nuclear@2 177 #define Z_BUF_ERROR (-5)
nuclear@2 178 #define Z_VERSION_ERROR (-6)
nuclear@2 179 /* Return codes for the compression/decompression functions. Negative
nuclear@2 180 * values are errors, positive values are used for special but normal events.
nuclear@2 181 */
nuclear@2 182
nuclear@2 183 #define Z_NO_COMPRESSION 0
nuclear@2 184 #define Z_BEST_SPEED 1
nuclear@2 185 #define Z_BEST_COMPRESSION 9
nuclear@2 186 #define Z_DEFAULT_COMPRESSION (-1)
nuclear@2 187 /* compression levels */
nuclear@2 188
nuclear@2 189 #define Z_FILTERED 1
nuclear@2 190 #define Z_HUFFMAN_ONLY 2
nuclear@2 191 #define Z_RLE 3
nuclear@2 192 #define Z_FIXED 4
nuclear@2 193 #define Z_DEFAULT_STRATEGY 0
nuclear@2 194 /* compression strategy; see deflateInit2() below for details */
nuclear@2 195
nuclear@2 196 #define Z_BINARY 0
nuclear@2 197 #define Z_TEXT 1
nuclear@2 198 #define Z_ASCII Z_TEXT /* for compatibility with 1.2.2 and earlier */
nuclear@2 199 #define Z_UNKNOWN 2
nuclear@2 200 /* Possible values of the data_type field (though see inflate()) */
nuclear@2 201
nuclear@2 202 #define Z_DEFLATED 8
nuclear@2 203 /* The deflate compression method (the only one supported in this version) */
nuclear@2 204
nuclear@2 205 #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */
nuclear@2 206
nuclear@2 207 #define zlib_version zlibVersion()
nuclear@2 208 /* for compatibility with versions < 1.0.2 */
nuclear@2 209
nuclear@2 210 /* basic functions */
nuclear@2 211
nuclear@2 212 ZEXTERN const char * ZEXPORT zlibVersion OF((void));
nuclear@2 213 /* The application can compare zlibVersion and ZLIB_VERSION for consistency.
nuclear@2 214 If the first character differs, the library code actually used is
nuclear@2 215 not compatible with the zlib.h header file used by the application.
nuclear@2 216 This check is automatically made by deflateInit and inflateInit.
nuclear@2 217 */
nuclear@2 218
nuclear@2 219 /*
nuclear@2 220 ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level));
nuclear@2 221
nuclear@2 222 Initializes the internal stream state for compression. The fields
nuclear@2 223 zalloc, zfree and opaque must be initialized before by the caller.
nuclear@2 224 If zalloc and zfree are set to Z_NULL, deflateInit updates them to
nuclear@2 225 use default allocation functions.
nuclear@2 226
nuclear@2 227 The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
nuclear@2 228 1 gives best speed, 9 gives best compression, 0 gives no compression at
nuclear@2 229 all (the input data is simply copied a block at a time).
nuclear@2 230 Z_DEFAULT_COMPRESSION requests a default compromise between speed and
nuclear@2 231 compression (currently equivalent to level 6).
nuclear@2 232
nuclear@2 233 deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not
nuclear@2 234 enough memory, Z_STREAM_ERROR if level is not a valid compression level,
nuclear@2 235 Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
nuclear@2 236 with the version assumed by the caller (ZLIB_VERSION).
nuclear@2 237 msg is set to null if there is no error message. deflateInit does not
nuclear@2 238 perform any compression: this will be done by deflate().
nuclear@2 239 */
nuclear@2 240
nuclear@2 241
nuclear@2 242 ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush));
nuclear@2 243 /*
nuclear@2 244 deflate compresses as much data as possible, and stops when the input
nuclear@2 245 buffer becomes empty or the output buffer becomes full. It may introduce some
nuclear@2 246 output latency (reading input without producing any output) except when
nuclear@2 247 forced to flush.
nuclear@2 248
nuclear@2 249 The detailed semantics are as follows. deflate performs one or both of the
nuclear@2 250 following actions:
nuclear@2 251
nuclear@2 252 - Compress more input starting at next_in and update next_in and avail_in
nuclear@2 253 accordingly. If not all input can be processed (because there is not
nuclear@2 254 enough room in the output buffer), next_in and avail_in are updated and
nuclear@2 255 processing will resume at this point for the next call of deflate().
nuclear@2 256
nuclear@2 257 - Provide more output starting at next_out and update next_out and avail_out
nuclear@2 258 accordingly. This action is forced if the parameter flush is non zero.
nuclear@2 259 Forcing flush frequently degrades the compression ratio, so this parameter
nuclear@2 260 should be set only when necessary (in interactive applications).
nuclear@2 261 Some output may be provided even if flush is not set.
nuclear@2 262
nuclear@2 263 Before the call of deflate(), the application should ensure that at least
nuclear@2 264 one of the actions is possible, by providing more input and/or consuming
nuclear@2 265 more output, and updating avail_in or avail_out accordingly; avail_out
nuclear@2 266 should never be zero before the call. The application can consume the
nuclear@2 267 compressed output when it wants, for example when the output buffer is full
nuclear@2 268 (avail_out == 0), or after each call of deflate(). If deflate returns Z_OK
nuclear@2 269 and with zero avail_out, it must be called again after making room in the
nuclear@2 270 output buffer because there might be more output pending.
nuclear@2 271
nuclear@2 272 Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to
nuclear@2 273 decide how much data to accumualte before producing output, in order to
nuclear@2 274 maximize compression.
nuclear@2 275
nuclear@2 276 If the parameter flush is set to Z_SYNC_FLUSH, all pending output is
nuclear@2 277 flushed to the output buffer and the output is aligned on a byte boundary, so
nuclear@2 278 that the decompressor can get all input data available so far. (In particular
nuclear@2 279 avail_in is zero after the call if enough output space has been provided
nuclear@2 280 before the call.) Flushing may degrade compression for some compression
nuclear@2 281 algorithms and so it should be used only when necessary.
nuclear@2 282
nuclear@2 283 If flush is set to Z_FULL_FLUSH, all output is flushed as with
nuclear@2 284 Z_SYNC_FLUSH, and the compression state is reset so that decompression can
nuclear@2 285 restart from this point if previous compressed data has been damaged or if
nuclear@2 286 random access is desired. Using Z_FULL_FLUSH too often can seriously degrade
nuclear@2 287 compression.
nuclear@2 288
nuclear@2 289 If deflate returns with avail_out == 0, this function must be called again
nuclear@2 290 with the same value of the flush parameter and more output space (updated
nuclear@2 291 avail_out), until the flush is complete (deflate returns with non-zero
nuclear@2 292 avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that
nuclear@2 293 avail_out is greater than six to avoid repeated flush markers due to
nuclear@2 294 avail_out == 0 on return.
nuclear@2 295
nuclear@2 296 If the parameter flush is set to Z_FINISH, pending input is processed,
nuclear@2 297 pending output is flushed and deflate returns with Z_STREAM_END if there
nuclear@2 298 was enough output space; if deflate returns with Z_OK, this function must be
nuclear@2 299 called again with Z_FINISH and more output space (updated avail_out) but no
nuclear@2 300 more input data, until it returns with Z_STREAM_END or an error. After
nuclear@2 301 deflate has returned Z_STREAM_END, the only possible operations on the
nuclear@2 302 stream are deflateReset or deflateEnd.
nuclear@2 303
nuclear@2 304 Z_FINISH can be used immediately after deflateInit if all the compression
nuclear@2 305 is to be done in a single step. In this case, avail_out must be at least
nuclear@2 306 the value returned by deflateBound (see below). If deflate does not return
nuclear@2 307 Z_STREAM_END, then it must be called again as described above.
nuclear@2 308
nuclear@2 309 deflate() sets strm->adler to the adler32 checksum of all input read
nuclear@2 310 so far (that is, total_in bytes).
nuclear@2 311
nuclear@2 312 deflate() may update strm->data_type if it can make a good guess about
nuclear@2 313 the input data type (Z_BINARY or Z_TEXT). In doubt, the data is considered
nuclear@2 314 binary. This field is only for information purposes and does not affect
nuclear@2 315 the compression algorithm in any manner.
nuclear@2 316
nuclear@2 317 deflate() returns Z_OK if some progress has been made (more input
nuclear@2 318 processed or more output produced), Z_STREAM_END if all input has been
nuclear@2 319 consumed and all output has been produced (only when flush is set to
nuclear@2 320 Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
nuclear@2 321 if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible
nuclear@2 322 (for example avail_in or avail_out was zero). Note that Z_BUF_ERROR is not
nuclear@2 323 fatal, and deflate() can be called again with more input and more output
nuclear@2 324 space to continue compressing.
nuclear@2 325 */
nuclear@2 326
nuclear@2 327
nuclear@2 328 ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm));
nuclear@2 329 /*
nuclear@2 330 All dynamically allocated data structures for this stream are freed.
nuclear@2 331 This function discards any unprocessed input and does not flush any
nuclear@2 332 pending output.
nuclear@2 333
nuclear@2 334 deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
nuclear@2 335 stream state was inconsistent, Z_DATA_ERROR if the stream was freed
nuclear@2 336 prematurely (some input or output was discarded). In the error case,
nuclear@2 337 msg may be set but then points to a static string (which must not be
nuclear@2 338 deallocated).
nuclear@2 339 */
nuclear@2 340
nuclear@2 341
nuclear@2 342 /*
nuclear@2 343 ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm));
nuclear@2 344
nuclear@2 345 Initializes the internal stream state for decompression. The fields
nuclear@2 346 next_in, avail_in, zalloc, zfree and opaque must be initialized before by
nuclear@2 347 the caller. If next_in is not Z_NULL and avail_in is large enough (the exact
nuclear@2 348 value depends on the compression method), inflateInit determines the
nuclear@2 349 compression method from the zlib header and allocates all data structures
nuclear@2 350 accordingly; otherwise the allocation will be deferred to the first call of
nuclear@2 351 inflate. If zalloc and zfree are set to Z_NULL, inflateInit updates them to
nuclear@2 352 use default allocation functions.
nuclear@2 353
nuclear@2 354 inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
nuclear@2 355 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
nuclear@2 356 version assumed by the caller. msg is set to null if there is no error
nuclear@2 357 message. inflateInit does not perform any decompression apart from reading
nuclear@2 358 the zlib header if present: this will be done by inflate(). (So next_in and
nuclear@2 359 avail_in may be modified, but next_out and avail_out are unchanged.)
nuclear@2 360 */
nuclear@2 361
nuclear@2 362
nuclear@2 363 ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush));
nuclear@2 364 /*
nuclear@2 365 inflate decompresses as much data as possible, and stops when the input
nuclear@2 366 buffer becomes empty or the output buffer becomes full. It may introduce
nuclear@2 367 some output latency (reading input without producing any output) except when
nuclear@2 368 forced to flush.
nuclear@2 369
nuclear@2 370 The detailed semantics are as follows. inflate performs one or both of the
nuclear@2 371 following actions:
nuclear@2 372
nuclear@2 373 - Decompress more input starting at next_in and update next_in and avail_in
nuclear@2 374 accordingly. If not all input can be processed (because there is not
nuclear@2 375 enough room in the output buffer), next_in is updated and processing
nuclear@2 376 will resume at this point for the next call of inflate().
nuclear@2 377
nuclear@2 378 - Provide more output starting at next_out and update next_out and avail_out
nuclear@2 379 accordingly. inflate() provides as much output as possible, until there
nuclear@2 380 is no more input data or no more space in the output buffer (see below
nuclear@2 381 about the flush parameter).
nuclear@2 382
nuclear@2 383 Before the call of inflate(), the application should ensure that at least
nuclear@2 384 one of the actions is possible, by providing more input and/or consuming
nuclear@2 385 more output, and updating the next_* and avail_* values accordingly.
nuclear@2 386 The application can consume the uncompressed output when it wants, for
nuclear@2 387 example when the output buffer is full (avail_out == 0), or after each
nuclear@2 388 call of inflate(). If inflate returns Z_OK and with zero avail_out, it
nuclear@2 389 must be called again after making room in the output buffer because there
nuclear@2 390 might be more output pending.
nuclear@2 391
nuclear@2 392 The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH,
nuclear@2 393 Z_FINISH, or Z_BLOCK. Z_SYNC_FLUSH requests that inflate() flush as much
nuclear@2 394 output as possible to the output buffer. Z_BLOCK requests that inflate() stop
nuclear@2 395 if and when it gets to the next deflate block boundary. When decoding the
nuclear@2 396 zlib or gzip format, this will cause inflate() to return immediately after
nuclear@2 397 the header and before the first block. When doing a raw inflate, inflate()
nuclear@2 398 will go ahead and process the first block, and will return when it gets to
nuclear@2 399 the end of that block, or when it runs out of data.
nuclear@2 400
nuclear@2 401 The Z_BLOCK option assists in appending to or combining deflate streams.
nuclear@2 402 Also to assist in this, on return inflate() will set strm->data_type to the
nuclear@2 403 number of unused bits in the last byte taken from strm->next_in, plus 64
nuclear@2 404 if inflate() is currently decoding the last block in the deflate stream,
nuclear@2 405 plus 128 if inflate() returned immediately after decoding an end-of-block
nuclear@2 406 code or decoding the complete header up to just before the first byte of the
nuclear@2 407 deflate stream. The end-of-block will not be indicated until all of the
nuclear@2 408 uncompressed data from that block has been written to strm->next_out. The
nuclear@2 409 number of unused bits may in general be greater than seven, except when
nuclear@2 410 bit 7 of data_type is set, in which case the number of unused bits will be
nuclear@2 411 less than eight.
nuclear@2 412
nuclear@2 413 inflate() should normally be called until it returns Z_STREAM_END or an
nuclear@2 414 error. However if all decompression is to be performed in a single step
nuclear@2 415 (a single call of inflate), the parameter flush should be set to
nuclear@2 416 Z_FINISH. In this case all pending input is processed and all pending
nuclear@2 417 output is flushed; avail_out must be large enough to hold all the
nuclear@2 418 uncompressed data. (The size of the uncompressed data may have been saved
nuclear@2 419 by the compressor for this purpose.) The next operation on this stream must
nuclear@2 420 be inflateEnd to deallocate the decompression state. The use of Z_FINISH
nuclear@2 421 is never required, but can be used to inform inflate that a faster approach
nuclear@2 422 may be used for the single inflate() call.
nuclear@2 423
nuclear@2 424 In this implementation, inflate() always flushes as much output as
nuclear@2 425 possible to the output buffer, and always uses the faster approach on the
nuclear@2 426 first call. So the only effect of the flush parameter in this implementation
nuclear@2 427 is on the return value of inflate(), as noted below, or when it returns early
nuclear@2 428 because Z_BLOCK is used.
nuclear@2 429
nuclear@2 430 If a preset dictionary is needed after this call (see inflateSetDictionary
nuclear@2 431 below), inflate sets strm->adler to the adler32 checksum of the dictionary
nuclear@2 432 chosen by the compressor and returns Z_NEED_DICT; otherwise it sets
nuclear@2 433 strm->adler to the adler32 checksum of all output produced so far (that is,
nuclear@2 434 total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described
nuclear@2 435 below. At the end of the stream, inflate() checks that its computed adler32
nuclear@2 436 checksum is equal to that saved by the compressor and returns Z_STREAM_END
nuclear@2 437 only if the checksum is correct.
nuclear@2 438
nuclear@2 439 inflate() will decompress and check either zlib-wrapped or gzip-wrapped
nuclear@2 440 deflate data. The header type is detected automatically. Any information
nuclear@2 441 contained in the gzip header is not retained, so applications that need that
nuclear@2 442 information should instead use raw inflate, see inflateInit2() below, or
nuclear@2 443 inflateBack() and perform their own processing of the gzip header and
nuclear@2 444 trailer.
nuclear@2 445
nuclear@2 446 inflate() returns Z_OK if some progress has been made (more input processed
nuclear@2 447 or more output produced), Z_STREAM_END if the end of the compressed data has
nuclear@2 448 been reached and all uncompressed output has been produced, Z_NEED_DICT if a
nuclear@2 449 preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
nuclear@2 450 corrupted (input stream not conforming to the zlib format or incorrect check
nuclear@2 451 value), Z_STREAM_ERROR if the stream structure was inconsistent (for example
nuclear@2 452 if next_in or next_out was NULL), Z_MEM_ERROR if there was not enough memory,
nuclear@2 453 Z_BUF_ERROR if no progress is possible or if there was not enough room in the
nuclear@2 454 output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and
nuclear@2 455 inflate() can be called again with more input and more output space to
nuclear@2 456 continue decompressing. If Z_DATA_ERROR is returned, the application may then
nuclear@2 457 call inflateSync() to look for a good compression block if a partial recovery
nuclear@2 458 of the data is desired.
nuclear@2 459 */
nuclear@2 460
nuclear@2 461
nuclear@2 462 ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm));
nuclear@2 463 /*
nuclear@2 464 All dynamically allocated data structures for this stream are freed.
nuclear@2 465 This function discards any unprocessed input and does not flush any
nuclear@2 466 pending output.
nuclear@2 467
nuclear@2 468 inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state
nuclear@2 469 was inconsistent. In the error case, msg may be set but then points to a
nuclear@2 470 static string (which must not be deallocated).
nuclear@2 471 */
nuclear@2 472
nuclear@2 473 /* Advanced functions */
nuclear@2 474
nuclear@2 475 /*
nuclear@2 476 The following functions are needed only in some special applications.
nuclear@2 477 */
nuclear@2 478
nuclear@2 479 /*
nuclear@2 480 ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm,
nuclear@2 481 int level,
nuclear@2 482 int method,
nuclear@2 483 int windowBits,
nuclear@2 484 int memLevel,
nuclear@2 485 int strategy));
nuclear@2 486
nuclear@2 487 This is another version of deflateInit with more compression options. The
nuclear@2 488 fields next_in, zalloc, zfree and opaque must be initialized before by
nuclear@2 489 the caller.
nuclear@2 490
nuclear@2 491 The method parameter is the compression method. It must be Z_DEFLATED in
nuclear@2 492 this version of the library.
nuclear@2 493
nuclear@2 494 The windowBits parameter is the base two logarithm of the window size
nuclear@2 495 (the size of the history buffer). It should be in the range 8..15 for this
nuclear@2 496 version of the library. Larger values of this parameter result in better
nuclear@2 497 compression at the expense of memory usage. The default value is 15 if
nuclear@2 498 deflateInit is used instead.
nuclear@2 499
nuclear@2 500 windowBits can also be -8..-15 for raw deflate. In this case, -windowBits
nuclear@2 501 determines the window size. deflate() will then generate raw deflate data
nuclear@2 502 with no zlib header or trailer, and will not compute an adler32 check value.
nuclear@2 503
nuclear@2 504 windowBits can also be greater than 15 for optional gzip encoding. Add
nuclear@2 505 16 to windowBits to write a simple gzip header and trailer around the
nuclear@2 506 compressed data instead of a zlib wrapper. The gzip header will have no
nuclear@2 507 file name, no extra data, no comment, no modification time (set to zero),
nuclear@2 508 no header crc, and the operating system will be set to 255 (unknown). If a
nuclear@2 509 gzip stream is being written, strm->adler is a crc32 instead of an adler32.
nuclear@2 510
nuclear@2 511 The memLevel parameter specifies how much memory should be allocated
nuclear@2 512 for the internal compression state. memLevel=1 uses minimum memory but
nuclear@2 513 is slow and reduces compression ratio; memLevel=9 uses maximum memory
nuclear@2 514 for optimal speed. The default value is 8. See zconf.h for total memory
nuclear@2 515 usage as a function of windowBits and memLevel.
nuclear@2 516
nuclear@2 517 The strategy parameter is used to tune the compression algorithm. Use the
nuclear@2 518 value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
nuclear@2 519 filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no
nuclear@2 520 string match), or Z_RLE to limit match distances to one (run-length
nuclear@2 521 encoding). Filtered data consists mostly of small values with a somewhat
nuclear@2 522 random distribution. In this case, the compression algorithm is tuned to
nuclear@2 523 compress them better. The effect of Z_FILTERED is to force more Huffman
nuclear@2 524 coding and less string matching; it is somewhat intermediate between
nuclear@2 525 Z_DEFAULT and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as fast as
nuclear@2 526 Z_HUFFMAN_ONLY, but give better compression for PNG image data. The strategy
nuclear@2 527 parameter only affects the compression ratio but not the correctness of the
nuclear@2 528 compressed output even if it is not set appropriately. Z_FIXED prevents the
nuclear@2 529 use of dynamic Huffman codes, allowing for a simpler decoder for special
nuclear@2 530 applications.
nuclear@2 531
nuclear@2 532 deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
nuclear@2 533 memory, Z_STREAM_ERROR if a parameter is invalid (such as an invalid
nuclear@2 534 method). msg is set to null if there is no error message. deflateInit2 does
nuclear@2 535 not perform any compression: this will be done by deflate().
nuclear@2 536 */
nuclear@2 537
nuclear@2 538 ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm,
nuclear@2 539 const Bytef *dictionary,
nuclear@2 540 uInt dictLength));
nuclear@2 541 /*
nuclear@2 542 Initializes the compression dictionary from the given byte sequence
nuclear@2 543 without producing any compressed output. This function must be called
nuclear@2 544 immediately after deflateInit, deflateInit2 or deflateReset, before any
nuclear@2 545 call of deflate. The compressor and decompressor must use exactly the same
nuclear@2 546 dictionary (see inflateSetDictionary).
nuclear@2 547
nuclear@2 548 The dictionary should consist of strings (byte sequences) that are likely
nuclear@2 549 to be encountered later in the data to be compressed, with the most commonly
nuclear@2 550 used strings preferably put towards the end of the dictionary. Using a
nuclear@2 551 dictionary is most useful when the data to be compressed is short and can be
nuclear@2 552 predicted with good accuracy; the data can then be compressed better than
nuclear@2 553 with the default empty dictionary.
nuclear@2 554
nuclear@2 555 Depending on the size of the compression data structures selected by
nuclear@2 556 deflateInit or deflateInit2, a part of the dictionary may in effect be
nuclear@2 557 discarded, for example if the dictionary is larger than the window size in
nuclear@2 558 deflate or deflate2. Thus the strings most likely to be useful should be
nuclear@2 559 put at the end of the dictionary, not at the front. In addition, the
nuclear@2 560 current implementation of deflate will use at most the window size minus
nuclear@2 561 262 bytes of the provided dictionary.
nuclear@2 562
nuclear@2 563 Upon return of this function, strm->adler is set to the adler32 value
nuclear@2 564 of the dictionary; the decompressor may later use this value to determine
nuclear@2 565 which dictionary has been used by the compressor. (The adler32 value
nuclear@2 566 applies to the whole dictionary even if only a subset of the dictionary is
nuclear@2 567 actually used by the compressor.) If a raw deflate was requested, then the
nuclear@2 568 adler32 value is not computed and strm->adler is not set.
nuclear@2 569
nuclear@2 570 deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
nuclear@2 571 parameter is invalid (such as NULL dictionary) or the stream state is
nuclear@2 572 inconsistent (for example if deflate has already been called for this stream
nuclear@2 573 or if the compression method is bsort). deflateSetDictionary does not
nuclear@2 574 perform any compression: this will be done by deflate().
nuclear@2 575 */
nuclear@2 576
nuclear@2 577 ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest,
nuclear@2 578 z_streamp source));
nuclear@2 579 /*
nuclear@2 580 Sets the destination stream as a complete copy of the source stream.
nuclear@2 581
nuclear@2 582 This function can be useful when several compression strategies will be
nuclear@2 583 tried, for example when there are several ways of pre-processing the input
nuclear@2 584 data with a filter. The streams that will be discarded should then be freed
nuclear@2 585 by calling deflateEnd. Note that deflateCopy duplicates the internal
nuclear@2 586 compression state which can be quite large, so this strategy is slow and
nuclear@2 587 can consume lots of memory.
nuclear@2 588
nuclear@2 589 deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
nuclear@2 590 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
nuclear@2 591 (such as zalloc being NULL). msg is left unchanged in both source and
nuclear@2 592 destination.
nuclear@2 593 */
nuclear@2 594
nuclear@2 595 ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm));
nuclear@2 596 /*
nuclear@2 597 This function is equivalent to deflateEnd followed by deflateInit,
nuclear@2 598 but does not free and reallocate all the internal compression state.
nuclear@2 599 The stream will keep the same compression level and any other attributes
nuclear@2 600 that may have been set by deflateInit2.
nuclear@2 601
nuclear@2 602 deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
nuclear@2 603 stream state was inconsistent (such as zalloc or state being NULL).
nuclear@2 604 */
nuclear@2 605
nuclear@2 606 ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm,
nuclear@2 607 int level,
nuclear@2 608 int strategy));
nuclear@2 609 /*
nuclear@2 610 Dynamically update the compression level and compression strategy. The
nuclear@2 611 interpretation of level and strategy is as in deflateInit2. This can be
nuclear@2 612 used to switch between compression and straight copy of the input data, or
nuclear@2 613 to switch to a different kind of input data requiring a different
nuclear@2 614 strategy. If the compression level is changed, the input available so far
nuclear@2 615 is compressed with the old level (and may be flushed); the new level will
nuclear@2 616 take effect only at the next call of deflate().
nuclear@2 617
nuclear@2 618 Before the call of deflateParams, the stream state must be set as for
nuclear@2 619 a call of deflate(), since the currently available input may have to
nuclear@2 620 be compressed and flushed. In particular, strm->avail_out must be non-zero.
nuclear@2 621
nuclear@2 622 deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source
nuclear@2 623 stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR
nuclear@2 624 if strm->avail_out was zero.
nuclear@2 625 */
nuclear@2 626
nuclear@2 627 ZEXTERN int ZEXPORT deflateTune OF((z_streamp strm,
nuclear@2 628 int good_length,
nuclear@2 629 int max_lazy,
nuclear@2 630 int nice_length,
nuclear@2 631 int max_chain));
nuclear@2 632 /*
nuclear@2 633 Fine tune deflate's internal compression parameters. This should only be
nuclear@2 634 used by someone who understands the algorithm used by zlib's deflate for
nuclear@2 635 searching for the best matching string, and even then only by the most
nuclear@2 636 fanatic optimizer trying to squeeze out the last compressed bit for their
nuclear@2 637 specific input data. Read the deflate.c source code for the meaning of the
nuclear@2 638 max_lazy, good_length, nice_length, and max_chain parameters.
nuclear@2 639
nuclear@2 640 deflateTune() can be called after deflateInit() or deflateInit2(), and
nuclear@2 641 returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream.
nuclear@2 642 */
nuclear@2 643
nuclear@2 644 ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm,
nuclear@2 645 uLong sourceLen));
nuclear@2 646 /*
nuclear@2 647 deflateBound() returns an upper bound on the compressed size after
nuclear@2 648 deflation of sourceLen bytes. It must be called after deflateInit()
nuclear@2 649 or deflateInit2(). This would be used to allocate an output buffer
nuclear@2 650 for deflation in a single pass, and so would be called before deflate().
nuclear@2 651 */
nuclear@2 652
nuclear@2 653 ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm,
nuclear@2 654 int bits,
nuclear@2 655 int value));
nuclear@2 656 /*
nuclear@2 657 deflatePrime() inserts bits in the deflate output stream. The intent
nuclear@2 658 is that this function is used to start off the deflate output with the
nuclear@2 659 bits leftover from a previous deflate stream when appending to it. As such,
nuclear@2 660 this function can only be used for raw deflate, and must be used before the
nuclear@2 661 first deflate() call after a deflateInit2() or deflateReset(). bits must be
nuclear@2 662 less than or equal to 16, and that many of the least significant bits of
nuclear@2 663 value will be inserted in the output.
nuclear@2 664
nuclear@2 665 deflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source
nuclear@2 666 stream state was inconsistent.
nuclear@2 667 */
nuclear@2 668
nuclear@2 669 ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm,
nuclear@2 670 gz_headerp head));
nuclear@2 671 /*
nuclear@2 672 deflateSetHeader() provides gzip header information for when a gzip
nuclear@2 673 stream is requested by deflateInit2(). deflateSetHeader() may be called
nuclear@2 674 after deflateInit2() or deflateReset() and before the first call of
nuclear@2 675 deflate(). The text, time, os, extra field, name, and comment information
nuclear@2 676 in the provided gz_header structure are written to the gzip header (xflag is
nuclear@2 677 ignored -- the extra flags are set according to the compression level). The
nuclear@2 678 caller must assure that, if not Z_NULL, name and comment are terminated with
nuclear@2 679 a zero byte, and that if extra is not Z_NULL, that extra_len bytes are
nuclear@2 680 available there. If hcrc is true, a gzip header crc is included. Note that
nuclear@2 681 the current versions of the command-line version of gzip (up through version
nuclear@2 682 1.3.x) do not support header crc's, and will report that it is a "multi-part
nuclear@2 683 gzip file" and give up.
nuclear@2 684
nuclear@2 685 If deflateSetHeader is not used, the default gzip header has text false,
nuclear@2 686 the time set to zero, and os set to 255, with no extra, name, or comment
nuclear@2 687 fields. The gzip header is returned to the default state by deflateReset().
nuclear@2 688
nuclear@2 689 deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
nuclear@2 690 stream state was inconsistent.
nuclear@2 691 */
nuclear@2 692
nuclear@2 693 /*
nuclear@2 694 ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm,
nuclear@2 695 int windowBits));
nuclear@2 696
nuclear@2 697 This is another version of inflateInit with an extra parameter. The
nuclear@2 698 fields next_in, avail_in, zalloc, zfree and opaque must be initialized
nuclear@2 699 before by the caller.
nuclear@2 700
nuclear@2 701 The windowBits parameter is the base two logarithm of the maximum window
nuclear@2 702 size (the size of the history buffer). It should be in the range 8..15 for
nuclear@2 703 this version of the library. The default value is 15 if inflateInit is used
nuclear@2 704 instead. windowBits must be greater than or equal to the windowBits value
nuclear@2 705 provided to deflateInit2() while compressing, or it must be equal to 15 if
nuclear@2 706 deflateInit2() was not used. If a compressed stream with a larger window
nuclear@2 707 size is given as input, inflate() will return with the error code
nuclear@2 708 Z_DATA_ERROR instead of trying to allocate a larger window.
nuclear@2 709
nuclear@2 710 windowBits can also be -8..-15 for raw inflate. In this case, -windowBits
nuclear@2 711 determines the window size. inflate() will then process raw deflate data,
nuclear@2 712 not looking for a zlib or gzip header, not generating a check value, and not
nuclear@2 713 looking for any check values for comparison at the end of the stream. This
nuclear@2 714 is for use with other formats that use the deflate compressed data format
nuclear@2 715 such as zip. Those formats provide their own check values. If a custom
nuclear@2 716 format is developed using the raw deflate format for compressed data, it is
nuclear@2 717 recommended that a check value such as an adler32 or a crc32 be applied to
nuclear@2 718 the uncompressed data as is done in the zlib, gzip, and zip formats. For
nuclear@2 719 most applications, the zlib format should be used as is. Note that comments
nuclear@2 720 above on the use in deflateInit2() applies to the magnitude of windowBits.
nuclear@2 721
nuclear@2 722 windowBits can also be greater than 15 for optional gzip decoding. Add
nuclear@2 723 32 to windowBits to enable zlib and gzip decoding with automatic header
nuclear@2 724 detection, or add 16 to decode only the gzip format (the zlib format will
nuclear@2 725 return a Z_DATA_ERROR). If a gzip stream is being decoded, strm->adler is
nuclear@2 726 a crc32 instead of an adler32.
nuclear@2 727
nuclear@2 728 inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
nuclear@2 729 memory, Z_STREAM_ERROR if a parameter is invalid (such as a null strm). msg
nuclear@2 730 is set to null if there is no error message. inflateInit2 does not perform
nuclear@2 731 any decompression apart from reading the zlib header if present: this will
nuclear@2 732 be done by inflate(). (So next_in and avail_in may be modified, but next_out
nuclear@2 733 and avail_out are unchanged.)
nuclear@2 734 */
nuclear@2 735
nuclear@2 736 ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm,
nuclear@2 737 const Bytef *dictionary,
nuclear@2 738 uInt dictLength));
nuclear@2 739 /*
nuclear@2 740 Initializes the decompression dictionary from the given uncompressed byte
nuclear@2 741 sequence. This function must be called immediately after a call of inflate,
nuclear@2 742 if that call returned Z_NEED_DICT. The dictionary chosen by the compressor
nuclear@2 743 can be determined from the adler32 value returned by that call of inflate.
nuclear@2 744 The compressor and decompressor must use exactly the same dictionary (see
nuclear@2 745 deflateSetDictionary). For raw inflate, this function can be called
nuclear@2 746 immediately after inflateInit2() or inflateReset() and before any call of
nuclear@2 747 inflate() to set the dictionary. The application must insure that the
nuclear@2 748 dictionary that was used for compression is provided.
nuclear@2 749
nuclear@2 750 inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
nuclear@2 751 parameter is invalid (such as NULL dictionary) or the stream state is
nuclear@2 752 inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
nuclear@2 753 expected one (incorrect adler32 value). inflateSetDictionary does not
nuclear@2 754 perform any decompression: this will be done by subsequent calls of
nuclear@2 755 inflate().
nuclear@2 756 */
nuclear@2 757
nuclear@2 758 ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm));
nuclear@2 759 /*
nuclear@2 760 Skips invalid compressed data until a full flush point (see above the
nuclear@2 761 description of deflate with Z_FULL_FLUSH) can be found, or until all
nuclear@2 762 available input is skipped. No output is provided.
nuclear@2 763
nuclear@2 764 inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR
nuclear@2 765 if no more input was provided, Z_DATA_ERROR if no flush point has been found,
nuclear@2 766 or Z_STREAM_ERROR if the stream structure was inconsistent. In the success
nuclear@2 767 case, the application may save the current current value of total_in which
nuclear@2 768 indicates where valid compressed data was found. In the error case, the
nuclear@2 769 application may repeatedly call inflateSync, providing more input each time,
nuclear@2 770 until success or end of the input data.
nuclear@2 771 */
nuclear@2 772
nuclear@2 773 ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest,
nuclear@2 774 z_streamp source));
nuclear@2 775 /*
nuclear@2 776 Sets the destination stream as a complete copy of the source stream.
nuclear@2 777
nuclear@2 778 This function can be useful when randomly accessing a large stream. The
nuclear@2 779 first pass through the stream can periodically record the inflate state,
nuclear@2 780 allowing restarting inflate at those points when randomly accessing the
nuclear@2 781 stream.
nuclear@2 782
nuclear@2 783 inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
nuclear@2 784 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
nuclear@2 785 (such as zalloc being NULL). msg is left unchanged in both source and
nuclear@2 786 destination.
nuclear@2 787 */
nuclear@2 788
nuclear@2 789 ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm));
nuclear@2 790 /*
nuclear@2 791 This function is equivalent to inflateEnd followed by inflateInit,
nuclear@2 792 but does not free and reallocate all the internal decompression state.
nuclear@2 793 The stream will keep attributes that may have been set by inflateInit2.
nuclear@2 794
nuclear@2 795 inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
nuclear@2 796 stream state was inconsistent (such as zalloc or state being NULL).
nuclear@2 797 */
nuclear@2 798
nuclear@2 799 ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm,
nuclear@2 800 int bits,
nuclear@2 801 int value));
nuclear@2 802 /*
nuclear@2 803 This function inserts bits in the inflate input stream. The intent is
nuclear@2 804 that this function is used to start inflating at a bit position in the
nuclear@2 805 middle of a byte. The provided bits will be used before any bytes are used
nuclear@2 806 from next_in. This function should only be used with raw inflate, and
nuclear@2 807 should be used before the first inflate() call after inflateInit2() or
nuclear@2 808 inflateReset(). bits must be less than or equal to 16, and that many of the
nuclear@2 809 least significant bits of value will be inserted in the input.
nuclear@2 810
nuclear@2 811 inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source
nuclear@2 812 stream state was inconsistent.
nuclear@2 813 */
nuclear@2 814
nuclear@2 815 ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm,
nuclear@2 816 gz_headerp head));
nuclear@2 817 /*
nuclear@2 818 inflateGetHeader() requests that gzip header information be stored in the
nuclear@2 819 provided gz_header structure. inflateGetHeader() may be called after
nuclear@2 820 inflateInit2() or inflateReset(), and before the first call of inflate().
nuclear@2 821 As inflate() processes the gzip stream, head->done is zero until the header
nuclear@2 822 is completed, at which time head->done is set to one. If a zlib stream is
nuclear@2 823 being decoded, then head->done is set to -1 to indicate that there will be
nuclear@2 824 no gzip header information forthcoming. Note that Z_BLOCK can be used to
nuclear@2 825 force inflate() to return immediately after header processing is complete
nuclear@2 826 and before any actual data is decompressed.
nuclear@2 827
nuclear@2 828 The text, time, xflags, and os fields are filled in with the gzip header
nuclear@2 829 contents. hcrc is set to true if there is a header CRC. (The header CRC
nuclear@2 830 was valid if done is set to one.) If extra is not Z_NULL, then extra_max
nuclear@2 831 contains the maximum number of bytes to write to extra. Once done is true,
nuclear@2 832 extra_len contains the actual extra field length, and extra contains the
nuclear@2 833 extra field, or that field truncated if extra_max is less than extra_len.
nuclear@2 834 If name is not Z_NULL, then up to name_max characters are written there,
nuclear@2 835 terminated with a zero unless the length is greater than name_max. If
nuclear@2 836 comment is not Z_NULL, then up to comm_max characters are written there,
nuclear@2 837 terminated with a zero unless the length is greater than comm_max. When
nuclear@2 838 any of extra, name, or comment are not Z_NULL and the respective field is
nuclear@2 839 not present in the header, then that field is set to Z_NULL to signal its
nuclear@2 840 absence. This allows the use of deflateSetHeader() with the returned
nuclear@2 841 structure to duplicate the header. However if those fields are set to
nuclear@2 842 allocated memory, then the application will need to save those pointers
nuclear@2 843 elsewhere so that they can be eventually freed.
nuclear@2 844
nuclear@2 845 If inflateGetHeader is not used, then the header information is simply
nuclear@2 846 discarded. The header is always checked for validity, including the header
nuclear@2 847 CRC if present. inflateReset() will reset the process to discard the header
nuclear@2 848 information. The application would need to call inflateGetHeader() again to
nuclear@2 849 retrieve the header from the next gzip stream.
nuclear@2 850
nuclear@2 851 inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
nuclear@2 852 stream state was inconsistent.
nuclear@2 853 */
nuclear@2 854
nuclear@2 855 /*
nuclear@2 856 ZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits,
nuclear@2 857 unsigned char FAR *window));
nuclear@2 858
nuclear@2 859 Initialize the internal stream state for decompression using inflateBack()
nuclear@2 860 calls. The fields zalloc, zfree and opaque in strm must be initialized
nuclear@2 861 before the call. If zalloc and zfree are Z_NULL, then the default library-
nuclear@2 862 derived memory allocation routines are used. windowBits is the base two
nuclear@2 863 logarithm of the window size, in the range 8..15. window is a caller
nuclear@2 864 supplied buffer of that size. Except for special applications where it is
nuclear@2 865 assured that deflate was used with small window sizes, windowBits must be 15
nuclear@2 866 and a 32K byte window must be supplied to be able to decompress general
nuclear@2 867 deflate streams.
nuclear@2 868
nuclear@2 869 See inflateBack() for the usage of these routines.
nuclear@2 870
nuclear@2 871 inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of
nuclear@2 872 the paramaters are invalid, Z_MEM_ERROR if the internal state could not
nuclear@2 873 be allocated, or Z_VERSION_ERROR if the version of the library does not
nuclear@2 874 match the version of the header file.
nuclear@2 875 */
nuclear@2 876
nuclear@2 877 typedef unsigned (*in_func) OF((void FAR *, unsigned char FAR * FAR *));
nuclear@2 878 typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned));
nuclear@2 879
nuclear@2 880 ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm,
nuclear@2 881 in_func in, void FAR *in_desc,
nuclear@2 882 out_func out, void FAR *out_desc));
nuclear@2 883 /*
nuclear@2 884 inflateBack() does a raw inflate with a single call using a call-back
nuclear@2 885 interface for input and output. This is more efficient than inflate() for
nuclear@2 886 file i/o applications in that it avoids copying between the output and the
nuclear@2 887 sliding window by simply making the window itself the output buffer. This
nuclear@2 888 function trusts the application to not change the output buffer passed by
nuclear@2 889 the output function, at least until inflateBack() returns.
nuclear@2 890
nuclear@2 891 inflateBackInit() must be called first to allocate the internal state
nuclear@2 892 and to initialize the state with the user-provided window buffer.
nuclear@2 893 inflateBack() may then be used multiple times to inflate a complete, raw
nuclear@2 894 deflate stream with each call. inflateBackEnd() is then called to free
nuclear@2 895 the allocated state.
nuclear@2 896
nuclear@2 897 A raw deflate stream is one with no zlib or gzip header or trailer.
nuclear@2 898 This routine would normally be used in a utility that reads zip or gzip
nuclear@2 899 files and writes out uncompressed files. The utility would decode the
nuclear@2 900 header and process the trailer on its own, hence this routine expects
nuclear@2 901 only the raw deflate stream to decompress. This is different from the
nuclear@2 902 normal behavior of inflate(), which expects either a zlib or gzip header and
nuclear@2 903 trailer around the deflate stream.
nuclear@2 904
nuclear@2 905 inflateBack() uses two subroutines supplied by the caller that are then
nuclear@2 906 called by inflateBack() for input and output. inflateBack() calls those
nuclear@2 907 routines until it reads a complete deflate stream and writes out all of the
nuclear@2 908 uncompressed data, or until it encounters an error. The function's
nuclear@2 909 parameters and return types are defined above in the in_func and out_func
nuclear@2 910 typedefs. inflateBack() will call in(in_desc, &buf) which should return the
nuclear@2 911 number of bytes of provided input, and a pointer to that input in buf. If
nuclear@2 912 there is no input available, in() must return zero--buf is ignored in that
nuclear@2 913 case--and inflateBack() will return a buffer error. inflateBack() will call
nuclear@2 914 out(out_desc, buf, len) to write the uncompressed data buf[0..len-1]. out()
nuclear@2 915 should return zero on success, or non-zero on failure. If out() returns
nuclear@2 916 non-zero, inflateBack() will return with an error. Neither in() nor out()
nuclear@2 917 are permitted to change the contents of the window provided to
nuclear@2 918 inflateBackInit(), which is also the buffer that out() uses to write from.
nuclear@2 919 The length written by out() will be at most the window size. Any non-zero
nuclear@2 920 amount of input may be provided by in().
nuclear@2 921
nuclear@2 922 For convenience, inflateBack() can be provided input on the first call by
nuclear@2 923 setting strm->next_in and strm->avail_in. If that input is exhausted, then
nuclear@2 924 in() will be called. Therefore strm->next_in must be initialized before
nuclear@2 925 calling inflateBack(). If strm->next_in is Z_NULL, then in() will be called
nuclear@2 926 immediately for input. If strm->next_in is not Z_NULL, then strm->avail_in
nuclear@2 927 must also be initialized, and then if strm->avail_in is not zero, input will
nuclear@2 928 initially be taken from strm->next_in[0 .. strm->avail_in - 1].
nuclear@2 929
nuclear@2 930 The in_desc and out_desc parameters of inflateBack() is passed as the
nuclear@2 931 first parameter of in() and out() respectively when they are called. These
nuclear@2 932 descriptors can be optionally used to pass any information that the caller-
nuclear@2 933 supplied in() and out() functions need to do their job.
nuclear@2 934
nuclear@2 935 On return, inflateBack() will set strm->next_in and strm->avail_in to
nuclear@2 936 pass back any unused input that was provided by the last in() call. The
nuclear@2 937 return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR
nuclear@2 938 if in() or out() returned an error, Z_DATA_ERROR if there was a format
nuclear@2 939 error in the deflate stream (in which case strm->msg is set to indicate the
nuclear@2 940 nature of the error), or Z_STREAM_ERROR if the stream was not properly
nuclear@2 941 initialized. In the case of Z_BUF_ERROR, an input or output error can be
nuclear@2 942 distinguished using strm->next_in which will be Z_NULL only if in() returned
nuclear@2 943 an error. If strm->next is not Z_NULL, then the Z_BUF_ERROR was due to
nuclear@2 944 out() returning non-zero. (in() will always be called before out(), so
nuclear@2 945 strm->next_in is assured to be defined if out() returns non-zero.) Note
nuclear@2 946 that inflateBack() cannot return Z_OK.
nuclear@2 947 */
nuclear@2 948
nuclear@2 949 ZEXTERN int ZEXPORT inflateBackEnd OF((z_streamp strm));
nuclear@2 950 /*
nuclear@2 951 All memory allocated by inflateBackInit() is freed.
nuclear@2 952
nuclear@2 953 inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream
nuclear@2 954 state was inconsistent.
nuclear@2 955 */
nuclear@2 956
nuclear@2 957 ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void));
nuclear@2 958 /* Return flags indicating compile-time options.
nuclear@2 959
nuclear@2 960 Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other:
nuclear@2 961 1.0: size of uInt
nuclear@2 962 3.2: size of uLong
nuclear@2 963 5.4: size of voidpf (pointer)
nuclear@2 964 7.6: size of z_off_t
nuclear@2 965
nuclear@2 966 Compiler, assembler, and debug options:
nuclear@2 967 8: DEBUG
nuclear@2 968 9: ASMV or ASMINF -- use ASM code
nuclear@2 969 10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention
nuclear@2 970 11: 0 (reserved)
nuclear@2 971
nuclear@2 972 One-time table building (smaller code, but not thread-safe if true):
nuclear@2 973 12: BUILDFIXED -- build static block decoding tables when needed
nuclear@2 974 13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed
nuclear@2 975 14,15: 0 (reserved)
nuclear@2 976
nuclear@2 977 Library content (indicates missing functionality):
nuclear@2 978 16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking
nuclear@2 979 deflate code when not needed)
nuclear@2 980 17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect
nuclear@2 981 and decode gzip streams (to avoid linking crc code)
nuclear@2 982 18-19: 0 (reserved)
nuclear@2 983
nuclear@2 984 Operation variations (changes in library functionality):
nuclear@2 985 20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate
nuclear@2 986 21: FASTEST -- deflate algorithm with only one, lowest compression level
nuclear@2 987 22,23: 0 (reserved)
nuclear@2 988
nuclear@2 989 The sprintf variant used by gzprintf (zero is best):
nuclear@2 990 24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format
nuclear@2 991 25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure!
nuclear@2 992 26: 0 = returns value, 1 = void -- 1 means inferred string length returned
nuclear@2 993
nuclear@2 994 Remainder:
nuclear@2 995 27-31: 0 (reserved)
nuclear@2 996 */
nuclear@2 997
nuclear@2 998
nuclear@2 999 /* utility functions */
nuclear@2 1000
nuclear@2 1001 /*
nuclear@2 1002 The following utility functions are implemented on top of the
nuclear@2 1003 basic stream-oriented functions. To simplify the interface, some
nuclear@2 1004 default options are assumed (compression level and memory usage,
nuclear@2 1005 standard memory allocation functions). The source code of these
nuclear@2 1006 utility functions can easily be modified if you need special options.
nuclear@2 1007 */
nuclear@2 1008
nuclear@2 1009 ZEXTERN int ZEXPORT compress OF((Bytef *dest, uLongf *destLen,
nuclear@2 1010 const Bytef *source, uLong sourceLen));
nuclear@2 1011 /*
nuclear@2 1012 Compresses the source buffer into the destination buffer. sourceLen is
nuclear@2 1013 the byte length of the source buffer. Upon entry, destLen is the total
nuclear@2 1014 size of the destination buffer, which must be at least the value returned
nuclear@2 1015 by compressBound(sourceLen). Upon exit, destLen is the actual size of the
nuclear@2 1016 compressed buffer.
nuclear@2 1017 This function can be used to compress a whole file at once if the
nuclear@2 1018 input file is mmap'ed.
nuclear@2 1019 compress returns Z_OK if success, Z_MEM_ERROR if there was not
nuclear@2 1020 enough memory, Z_BUF_ERROR if there was not enough room in the output
nuclear@2 1021 buffer.
nuclear@2 1022 */
nuclear@2 1023
nuclear@2 1024 ZEXTERN int ZEXPORT compress2 OF((Bytef *dest, uLongf *destLen,
nuclear@2 1025 const Bytef *source, uLong sourceLen,
nuclear@2 1026 int level));
nuclear@2 1027 /*
nuclear@2 1028 Compresses the source buffer into the destination buffer. The level
nuclear@2 1029 parameter has the same meaning as in deflateInit. sourceLen is the byte
nuclear@2 1030 length of the source buffer. Upon entry, destLen is the total size of the
nuclear@2 1031 destination buffer, which must be at least the value returned by
nuclear@2 1032 compressBound(sourceLen). Upon exit, destLen is the actual size of the
nuclear@2 1033 compressed buffer.
nuclear@2 1034
nuclear@2 1035 compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
nuclear@2 1036 memory, Z_BUF_ERROR if there was not enough room in the output buffer,
nuclear@2 1037 Z_STREAM_ERROR if the level parameter is invalid.
nuclear@2 1038 */
nuclear@2 1039
nuclear@2 1040 ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen));
nuclear@2 1041 /*
nuclear@2 1042 compressBound() returns an upper bound on the compressed size after
nuclear@2 1043 compress() or compress2() on sourceLen bytes. It would be used before
nuclear@2 1044 a compress() or compress2() call to allocate the destination buffer.
nuclear@2 1045 */
nuclear@2 1046
nuclear@2 1047 ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen,
nuclear@2 1048 const Bytef *source, uLong sourceLen));
nuclear@2 1049 /*
nuclear@2 1050 Decompresses the source buffer into the destination buffer. sourceLen is
nuclear@2 1051 the byte length of the source buffer. Upon entry, destLen is the total
nuclear@2 1052 size of the destination buffer, which must be large enough to hold the
nuclear@2 1053 entire uncompressed data. (The size of the uncompressed data must have
nuclear@2 1054 been saved previously by the compressor and transmitted to the decompressor
nuclear@2 1055 by some mechanism outside the scope of this compression library.)
nuclear@2 1056 Upon exit, destLen is the actual size of the compressed buffer.
nuclear@2 1057 This function can be used to decompress a whole file at once if the
nuclear@2 1058 input file is mmap'ed.
nuclear@2 1059
nuclear@2 1060 uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
nuclear@2 1061 enough memory, Z_BUF_ERROR if there was not enough room in the output
nuclear@2 1062 buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete.
nuclear@2 1063 */
nuclear@2 1064
nuclear@2 1065
nuclear@2 1066 typedef voidp gzFile;
nuclear@2 1067
nuclear@2 1068 ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode));
nuclear@2 1069 /*
nuclear@2 1070 Opens a gzip (.gz) file for reading or writing. The mode parameter
nuclear@2 1071 is as in fopen ("rb" or "wb") but can also include a compression level
nuclear@2 1072 ("wb9") or a strategy: 'f' for filtered data as in "wb6f", 'h' for
nuclear@2 1073 Huffman only compression as in "wb1h", or 'R' for run-length encoding
nuclear@2 1074 as in "wb1R". (See the description of deflateInit2 for more information
nuclear@2 1075 about the strategy parameter.)
nuclear@2 1076
nuclear@2 1077 gzopen can be used to read a file which is not in gzip format; in this
nuclear@2 1078 case gzread will directly read from the file without decompression.
nuclear@2 1079
nuclear@2 1080 gzopen returns NULL if the file could not be opened or if there was
nuclear@2 1081 insufficient memory to allocate the (de)compression state; errno
nuclear@2 1082 can be checked to distinguish the two cases (if errno is zero, the
nuclear@2 1083 zlib error is Z_MEM_ERROR). */
nuclear@2 1084
nuclear@2 1085 ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode));
nuclear@2 1086 /*
nuclear@2 1087 gzdopen() associates a gzFile with the file descriptor fd. File
nuclear@2 1088 descriptors are obtained from calls like open, dup, creat, pipe or
nuclear@2 1089 fileno (in the file has been previously opened with fopen).
nuclear@2 1090 The mode parameter is as in gzopen.
nuclear@2 1091 The next call of gzclose on the returned gzFile will also close the
nuclear@2 1092 file descriptor fd, just like fclose(fdopen(fd), mode) closes the file
nuclear@2 1093 descriptor fd. If you want to keep fd open, use gzdopen(dup(fd), mode).
nuclear@2 1094 gzdopen returns NULL if there was insufficient memory to allocate
nuclear@2 1095 the (de)compression state.
nuclear@2 1096 */
nuclear@2 1097
nuclear@2 1098 ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy));
nuclear@2 1099 /*
nuclear@2 1100 Dynamically update the compression level or strategy. See the description
nuclear@2 1101 of deflateInit2 for the meaning of these parameters.
nuclear@2 1102 gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not
nuclear@2 1103 opened for writing.
nuclear@2 1104 */
nuclear@2 1105
nuclear@2 1106 ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len));
nuclear@2 1107 /*
nuclear@2 1108 Reads the given number of uncompressed bytes from the compressed file.
nuclear@2 1109 If the input file was not in gzip format, gzread copies the given number
nuclear@2 1110 of bytes into the buffer.
nuclear@2 1111 gzread returns the number of uncompressed bytes actually read (0 for
nuclear@2 1112 end of file, -1 for error). */
nuclear@2 1113
nuclear@2 1114 ZEXTERN int ZEXPORT gzwrite OF((gzFile file,
nuclear@2 1115 voidpc buf, unsigned len));
nuclear@2 1116 /*
nuclear@2 1117 Writes the given number of uncompressed bytes into the compressed file.
nuclear@2 1118 gzwrite returns the number of uncompressed bytes actually written
nuclear@2 1119 (0 in case of error).
nuclear@2 1120 */
nuclear@2 1121
nuclear@2 1122 ZEXTERN int ZEXPORTVA gzprintf OF((gzFile file, const char *format, ...));
nuclear@2 1123 /*
nuclear@2 1124 Converts, formats, and writes the args to the compressed file under
nuclear@2 1125 control of the format string, as in fprintf. gzprintf returns the number of
nuclear@2 1126 uncompressed bytes actually written (0 in case of error). The number of
nuclear@2 1127 uncompressed bytes written is limited to 4095. The caller should assure that
nuclear@2 1128 this limit is not exceeded. If it is exceeded, then gzprintf() will return
nuclear@2 1129 return an error (0) with nothing written. In this case, there may also be a
nuclear@2 1130 buffer overflow with unpredictable consequences, which is possible only if
nuclear@2 1131 zlib was compiled with the insecure functions sprintf() or vsprintf()
nuclear@2 1132 because the secure snprintf() or vsnprintf() functions were not available.
nuclear@2 1133 */
nuclear@2 1134
nuclear@2 1135 ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s));
nuclear@2 1136 /*
nuclear@2 1137 Writes the given null-terminated string to the compressed file, excluding
nuclear@2 1138 the terminating null character.
nuclear@2 1139 gzputs returns the number of characters written, or -1 in case of error.
nuclear@2 1140 */
nuclear@2 1141
nuclear@2 1142 ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len));
nuclear@2 1143 /*
nuclear@2 1144 Reads bytes from the compressed file until len-1 characters are read, or
nuclear@2 1145 a newline character is read and transferred to buf, or an end-of-file
nuclear@2 1146 condition is encountered. The string is then terminated with a null
nuclear@2 1147 character.
nuclear@2 1148 gzgets returns buf, or Z_NULL in case of error.
nuclear@2 1149 */
nuclear@2 1150
nuclear@2 1151 ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c));
nuclear@2 1152 /*
nuclear@2 1153 Writes c, converted to an unsigned char, into the compressed file.
nuclear@2 1154 gzputc returns the value that was written, or -1 in case of error.
nuclear@2 1155 */
nuclear@2 1156
nuclear@2 1157 ZEXTERN int ZEXPORT gzgetc OF((gzFile file));
nuclear@2 1158 /*
nuclear@2 1159 Reads one byte from the compressed file. gzgetc returns this byte
nuclear@2 1160 or -1 in case of end of file or error.
nuclear@2 1161 */
nuclear@2 1162
nuclear@2 1163 ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file));
nuclear@2 1164 /*
nuclear@2 1165 Push one character back onto the stream to be read again later.
nuclear@2 1166 Only one character of push-back is allowed. gzungetc() returns the
nuclear@2 1167 character pushed, or -1 on failure. gzungetc() will fail if a
nuclear@2 1168 character has been pushed but not read yet, or if c is -1. The pushed
nuclear@2 1169 character will be discarded if the stream is repositioned with gzseek()
nuclear@2 1170 or gzrewind().
nuclear@2 1171 */
nuclear@2 1172
nuclear@2 1173 ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush));
nuclear@2 1174 /*
nuclear@2 1175 Flushes all pending output into the compressed file. The parameter
nuclear@2 1176 flush is as in the deflate() function. The return value is the zlib
nuclear@2 1177 error number (see function gzerror below). gzflush returns Z_OK if
nuclear@2 1178 the flush parameter is Z_FINISH and all output could be flushed.
nuclear@2 1179 gzflush should be called only when strictly necessary because it can
nuclear@2 1180 degrade compression.
nuclear@2 1181 */
nuclear@2 1182
nuclear@2 1183 ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file,
nuclear@2 1184 z_off_t offset, int whence));
nuclear@2 1185 /*
nuclear@2 1186 Sets the starting position for the next gzread or gzwrite on the
nuclear@2 1187 given compressed file. The offset represents a number of bytes in the
nuclear@2 1188 uncompressed data stream. The whence parameter is defined as in lseek(2);
nuclear@2 1189 the value SEEK_END is not supported.
nuclear@2 1190 If the file is opened for reading, this function is emulated but can be
nuclear@2 1191 extremely slow. If the file is opened for writing, only forward seeks are
nuclear@2 1192 supported; gzseek then compresses a sequence of zeroes up to the new
nuclear@2 1193 starting position.
nuclear@2 1194
nuclear@2 1195 gzseek returns the resulting offset location as measured in bytes from
nuclear@2 1196 the beginning of the uncompressed stream, or -1 in case of error, in
nuclear@2 1197 particular if the file is opened for writing and the new starting position
nuclear@2 1198 would be before the current position.
nuclear@2 1199 */
nuclear@2 1200
nuclear@2 1201 ZEXTERN int ZEXPORT gzrewind OF((gzFile file));
nuclear@2 1202 /*
nuclear@2 1203 Rewinds the given file. This function is supported only for reading.
nuclear@2 1204
nuclear@2 1205 gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET)
nuclear@2 1206 */
nuclear@2 1207
nuclear@2 1208 ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file));
nuclear@2 1209 /*
nuclear@2 1210 Returns the starting position for the next gzread or gzwrite on the
nuclear@2 1211 given compressed file. This position represents a number of bytes in the
nuclear@2 1212 uncompressed data stream.
nuclear@2 1213
nuclear@2 1214 gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)
nuclear@2 1215 */
nuclear@2 1216
nuclear@2 1217 ZEXTERN int ZEXPORT gzeof OF((gzFile file));
nuclear@2 1218 /*
nuclear@2 1219 Returns 1 when EOF has previously been detected reading the given
nuclear@2 1220 input stream, otherwise zero.
nuclear@2 1221 */
nuclear@2 1222
nuclear@2 1223 ZEXTERN int ZEXPORT gzdirect OF((gzFile file));
nuclear@2 1224 /*
nuclear@2 1225 Returns 1 if file is being read directly without decompression, otherwise
nuclear@2 1226 zero.
nuclear@2 1227 */
nuclear@2 1228
nuclear@2 1229 ZEXTERN int ZEXPORT gzclose OF((gzFile file));
nuclear@2 1230 /*
nuclear@2 1231 Flushes all pending output if necessary, closes the compressed file
nuclear@2 1232 and deallocates all the (de)compression state. The return value is the zlib
nuclear@2 1233 error number (see function gzerror below).
nuclear@2 1234 */
nuclear@2 1235
nuclear@2 1236 ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum));
nuclear@2 1237 /*
nuclear@2 1238 Returns the error message for the last error which occurred on the
nuclear@2 1239 given compressed file. errnum is set to zlib error number. If an
nuclear@2 1240 error occurred in the file system and not in the compression library,
nuclear@2 1241 errnum is set to Z_ERRNO and the application may consult errno
nuclear@2 1242 to get the exact error code.
nuclear@2 1243 */
nuclear@2 1244
nuclear@2 1245 ZEXTERN void ZEXPORT gzclearerr OF((gzFile file));
nuclear@2 1246 /*
nuclear@2 1247 Clears the error and end-of-file flags for file. This is analogous to the
nuclear@2 1248 clearerr() function in stdio. This is useful for continuing to read a gzip
nuclear@2 1249 file that is being written concurrently.
nuclear@2 1250 */
nuclear@2 1251
nuclear@2 1252 /* checksum functions */
nuclear@2 1253
nuclear@2 1254 /*
nuclear@2 1255 These functions are not related to compression but are exported
nuclear@2 1256 anyway because they might be useful in applications using the
nuclear@2 1257 compression library.
nuclear@2 1258 */
nuclear@2 1259
nuclear@2 1260 ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len));
nuclear@2 1261 /*
nuclear@2 1262 Update a running Adler-32 checksum with the bytes buf[0..len-1] and
nuclear@2 1263 return the updated checksum. If buf is NULL, this function returns
nuclear@2 1264 the required initial value for the checksum.
nuclear@2 1265 An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
nuclear@2 1266 much faster. Usage example:
nuclear@2 1267
nuclear@2 1268 uLong adler = adler32(0L, Z_NULL, 0);
nuclear@2 1269
nuclear@2 1270 while (read_buffer(buffer, length) != EOF) {
nuclear@2 1271 adler = adler32(adler, buffer, length);
nuclear@2 1272 }
nuclear@2 1273 if (adler != original_adler) error();
nuclear@2 1274 */
nuclear@2 1275
nuclear@2 1276 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong adler1, uLong adler2,
nuclear@2 1277 z_off_t len2));
nuclear@2 1278 /*
nuclear@2 1279 Combine two Adler-32 checksums into one. For two sequences of bytes, seq1
nuclear@2 1280 and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for
nuclear@2 1281 each, adler1 and adler2. adler32_combine() returns the Adler-32 checksum of
nuclear@2 1282 seq1 and seq2 concatenated, requiring only adler1, adler2, and len2.
nuclear@2 1283 */
nuclear@2 1284
nuclear@2 1285 ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len));
nuclear@2 1286 /*
nuclear@2 1287 Update a running CRC-32 with the bytes buf[0..len-1] and return the
nuclear@2 1288 updated CRC-32. If buf is NULL, this function returns the required initial
nuclear@2 1289 value for the for the crc. Pre- and post-conditioning (one's complement) is
nuclear@2 1290 performed within this function so it shouldn't be done by the application.
nuclear@2 1291 Usage example:
nuclear@2 1292
nuclear@2 1293 uLong crc = crc32(0L, Z_NULL, 0);
nuclear@2 1294
nuclear@2 1295 while (read_buffer(buffer, length) != EOF) {
nuclear@2 1296 crc = crc32(crc, buffer, length);
nuclear@2 1297 }
nuclear@2 1298 if (crc != original_crc) error();
nuclear@2 1299 */
nuclear@2 1300
nuclear@2 1301 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2));
nuclear@2 1302
nuclear@2 1303 /*
nuclear@2 1304 Combine two CRC-32 check values into one. For two sequences of bytes,
nuclear@2 1305 seq1 and seq2 with lengths len1 and len2, CRC-32 check values were
nuclear@2 1306 calculated for each, crc1 and crc2. crc32_combine() returns the CRC-32
nuclear@2 1307 check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and
nuclear@2 1308 len2.
nuclear@2 1309 */
nuclear@2 1310
nuclear@2 1311
nuclear@2 1312 /* various hacks, don't look :) */
nuclear@2 1313
nuclear@2 1314 /* deflateInit and inflateInit are macros to allow checking the zlib version
nuclear@2 1315 * and the compiler's view of z_stream:
nuclear@2 1316 */
nuclear@2 1317 ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level,
nuclear@2 1318 const char *version, int stream_size));
nuclear@2 1319 ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm,
nuclear@2 1320 const char *version, int stream_size));
nuclear@2 1321 ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method,
nuclear@2 1322 int windowBits, int memLevel,
nuclear@2 1323 int strategy, const char *version,
nuclear@2 1324 int stream_size));
nuclear@2 1325 ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits,
nuclear@2 1326 const char *version, int stream_size));
nuclear@2 1327 ZEXTERN int ZEXPORT inflateBackInit_ OF((z_streamp strm, int windowBits,
nuclear@2 1328 unsigned char FAR *window,
nuclear@2 1329 const char *version,
nuclear@2 1330 int stream_size));
nuclear@2 1331 #define deflateInit(strm, level) \
nuclear@2 1332 deflateInit_((strm), (level), ZLIB_VERSION, sizeof(z_stream))
nuclear@2 1333 #define inflateInit(strm) \
nuclear@2 1334 inflateInit_((strm), ZLIB_VERSION, sizeof(z_stream))
nuclear@2 1335 #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
nuclear@2 1336 deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
nuclear@2 1337 (strategy), ZLIB_VERSION, sizeof(z_stream))
nuclear@2 1338 #define inflateInit2(strm, windowBits) \
nuclear@2 1339 inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream))
nuclear@2 1340 #define inflateBackInit(strm, windowBits, window) \
nuclear@2 1341 inflateBackInit_((strm), (windowBits), (window), \
nuclear@2 1342 ZLIB_VERSION, sizeof(z_stream))
nuclear@2 1343
nuclear@2 1344
nuclear@2 1345 #if !defined(ZUTIL_H) && !defined(NO_DUMMY_DECL)
nuclear@2 1346 struct internal_state {int dummy;}; /* hack for buggy compilers */
nuclear@2 1347 #endif
nuclear@2 1348
nuclear@2 1349 ZEXTERN const char * ZEXPORT zError OF((int));
nuclear@2 1350 ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp z));
nuclear@2 1351 ZEXTERN const uLongf * ZEXPORT get_crc_table OF((void));
nuclear@2 1352
nuclear@2 1353 #ifdef __cplusplus
nuclear@2 1354 }
nuclear@2 1355 #endif
nuclear@2 1356
nuclear@2 1357 #endif /* ZLIB_H */