00001 /* zlib.h -- interface of the 'zlib' general purpose compression library
00002 version 1.1.3, July 9th, 1998
00003
00004 Copyright (C) 1995-1998 Jean-loup Gailly and Mark Adler
00005
00006 This software is provided 'as-is', without any express or implied
00007 warranty. In no event will the authors be held liable for any damages
00008 arising from the use of this software.
00009
00010 Permission is granted to anyone to use this software for any purpose,
00011 including commercial applications, and to alter it and redistribute it
00012 freely, subject to the following restrictions:
00013
00014 1. The origin of this software must not be misrepresented; you must not
00015 claim that you wrote the original software. If you use this software
00016 in a product, an acknowledgment in the product documentation would be
00017 appreciated but is not required.
00018 2. Altered source versions must be plainly marked as such, and must not be
00019 misrepresented as being the original software.
00020 3. This notice may not be removed or altered from any source distribution.
00021
00022 Jean-loup Gailly Mark Adler
00023 jloup@gzip.org madler@alumni.caltech.edu
00024
00025
00026 The data format used by the zlib library is described by RFCs (Request for
00027 Comments) 1950 to 1952 in the files ftp://ds.internic.net/rfc/rfc1950.txt
00028 (zlib format), rfc1951.txt (deflate format) and rfc1952.txt (gzip format).
00029 */
00030
00031 #ifndef _ZLIB_H
00032 #define _ZLIB_H
00033
00034 #include "zconf.h"
00035
00036 #ifdef __cplusplus
00037 extern "C" {
00038 #endif
00039
00040 #define ZLIB_VERSION "1.1.3"
00041
00042 /*
00043 The 'zlib' compression library provides in-memory compression and
00044 decompression functions, including integrity checks of the uncompressed
00045 data. This version of the library supports only one compression method
00046 (deflation) but other algorithms will be added later and will have the same
00047 stream interface.
00048
00049 Compression can be done in a single step if the buffers are large
00050 enough (for example if an input file is mmap'ed), or can be done by
00051 repeated calls of the compression function. In the latter case, the
00052 application must provide more input and/or consume the output
00053 (providing more output space) before each call.
00054
00055 The library also supports reading and writing files in gzip (.gz) format
00056 with an interface similar to that of stdio.
00057
00058 The library does not install any signal handler. The decoder checks
00059 the consistency of the compressed data, so the library should never
00060 crash even in case of corrupted input.
00061 */
00062
00063 typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size));
00064 typedef void (*free_func) OF((voidpf opaque, voidpf address));
00065
00066 struct internal_state;
00067
00068 typedef struct z_stream_s {
00069 Bytef *next_in; /* next input byte */
00070 uInt avail_in; /* number of bytes available at next_in */
00071 uLong total_in; /* total nb of input bytes read so far */
00072
00073 Bytef *next_out; /* next output byte should be put there */
00074 uInt avail_out; /* remaining free space at next_out */
00075 uLong total_out; /* total nb of bytes output so far */
00076
00077 char *msg; /* last error message, NULL if no error */
00078 struct internal_state FAR *state; /* not visible by applications */
00079
00080 alloc_func zalloc; /* used to allocate the internal state */
00081 free_func zfree; /* used to free the internal state */
00082 voidpf opaque; /* private data object passed to zalloc and zfree */
00083
00084 int data_type; /* best guess about the data type: ascii or binary */
00085 uLong adler; /* adler32 value of the uncompressed data */
00086 uLong reserved; /* reserved for future use */
00087 } z_stream;
00088
00089 typedef z_stream FAR *z_streamp;
00090
00091 /*
00092 The application must update next_in and avail_in when avail_in has
00093 dropped to zero. It must update next_out and avail_out when avail_out
00094 has dropped to zero. The application must initialize zalloc, zfree and
00095 opaque before calling the init function. All other fields are set by the
00096 compression library and must not be updated by the application.
00097
00098 The opaque value provided by the application will be passed as the first
00099 parameter for calls of zalloc and zfree. This can be useful for custom
00100 memory management. The compression library attaches no meaning to the
00101 opaque value.
00102
00103 zalloc must return Z_NULL if there is not enough memory for the object.
00104 If zlib is used in a multi-threaded application, zalloc and zfree must be
00105 thread safe.
00106
00107 On 16-bit systems, the functions zalloc and zfree must be able to allocate
00108 exactly 65536 bytes, but will not be required to allocate more than this
00109 if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS,
00110 pointers returned by zalloc for objects of exactly 65536 bytes *must*
00111 have their offset normalized to zero. The default allocation function
00112 provided by this library ensures this (see zutil.c). To reduce memory
00113 requirements and avoid any allocation of 64K objects, at the expense of
00114 compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h).
00115
00116 The fields total_in and total_out can be used for statistics or
00117 progress reports. After compression, total_in holds the total size of
00118 the uncompressed data and may be saved for use in the decompressor
00119 (particularly if the decompressor wants to decompress everything in
00120 a single step).
00121 */
00122
00123 /* constants */
00124
00125 #define Z_NO_FLUSH 0
00126 #define Z_PARTIAL_FLUSH 1 /* will be removed, use Z_SYNC_FLUSH instead */
00127 #define Z_SYNC_FLUSH 2
00128 #define Z_FULL_FLUSH 3
00129 #define Z_FINISH 4
00130 /* Allowed flush values; see deflate() below for details */
00131
00132 #define Z_OK 0
00133 #define Z_STREAM_END 1
00134 #define Z_NEED_DICT 2
00135 #define Z_ERRNO (-1)
00136 #define Z_STREAM_ERROR (-2)
00137 #define Z_DATA_ERROR (-3)
00138 #define Z_MEM_ERROR (-4)
00139 #define Z_BUF_ERROR (-5)
00140 #define Z_VERSION_ERROR (-6)
00141 /* Return codes for the compression/decompression functions. Negative
00142 * values are errors, positive values are used for special but normal events.
00143 */
00144
00145 #define Z_NO_COMPRESSION 0
00146 #define Z_BEST_SPEED 1
00147 #define Z_BEST_COMPRESSION 9
00148 #define Z_DEFAULT_COMPRESSION (-1)
00149 /* compression levels */
00150
00151 #define Z_FILTERED 1
00152 #define Z_HUFFMAN_ONLY 2
00153 #define Z_DEFAULT_STRATEGY 0
00154 /* compression strategy; see deflateInit2() below for details */
00155
00156 #define Z_BINARY 0
00157 #define Z_ASCII 1
00158 #define Z_UNKNOWN 2
00159 /* Possible values of the data_type field */
00160
00161 #define Z_DEFLATED 8
00162 /* The deflate compression method (the only one supported in this version) */
00163
00164 #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */
00165
00166 #define zlib_version zlibVersion()
00167 /* for compatibility with versions < 1.0.2 */
00168
00169 /* basic functions */
00170
00171 ZEXTERN const char * ZEXPORT zlibVersion OF((void));
00172 /* The application can compare zlibVersion and ZLIB_VERSION for consistency.
00173 If the first character differs, the library code actually used is
00174 not compatible with the zlib.h header file used by the application.
00175 This check is automatically made by deflateInit and inflateInit.
00176 */
00177
00178 /*
00179 ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level));
00180
00181 Initializes the internal stream state for compression. The fields
00182 zalloc, zfree and opaque must be initialized before by the caller.
00183 If zalloc and zfree are set to Z_NULL, deflateInit updates them to
00184 use default allocation functions.
00185
00186 The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
00187 1 gives best speed, 9 gives best compression, 0 gives no compression at
00188 all (the input data is simply copied a block at a time).
00189 Z_DEFAULT_COMPRESSION requests a default compromise between speed and
00190 compression (currently equivalent to level 6).
00191
00192 deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not
00193 enough memory, Z_STREAM_ERROR if level is not a valid compression level,
00194 Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
00195 with the version assumed by the caller (ZLIB_VERSION).
00196 msg is set to null if there is no error message. deflateInit does not
00197 perform any compression: this will be done by deflate().
00198 */
00199
00200
00201 ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush));
00202 /*
00203 deflate compresses as much data as possible, and stops when the input
00204 buffer becomes empty or the output buffer becomes full. It may introduce some
00205 output latency (reading input without producing any output) except when
00206 forced to flush.
00207
00208 The detailed semantics are as follows. deflate performs one or both of the
00209 following actions:
00210
00211 - Compress more input starting at next_in and update next_in and avail_in
00212 accordingly. If not all input can be processed (because there is not
00213 enough room in the output buffer), next_in and avail_in are updated and
00214 processing will resume at this point for the next call of deflate().
00215
00216 - Provide more output starting at next_out and update next_out and avail_out
00217 accordingly. This action is forced if the parameter flush is non zero.
00218 Forcing flush frequently degrades the compression ratio, so this parameter
00219 should be set only when necessary (in interactive applications).
00220 Some output may be provided even if flush is not set.
00221
00222 Before the call of deflate(), the application should ensure that at least
00223 one of the actions is possible, by providing more input and/or consuming
00224 more output, and updating avail_in or avail_out accordingly; avail_out
00225 should never be zero before the call. The application can consume the
00226 compressed output when it wants, for example when the output buffer is full
00227 (avail_out == 0), or after each call of deflate(). If deflate returns Z_OK
00228 and with zero avail_out, it must be called again after making room in the
00229 output buffer because there might be more output pending.
00230
00231 If the parameter flush is set to Z_SYNC_FLUSH, all pending output is
00232 flushed to the output buffer and the output is aligned on a byte boundary, so
00233 that the decompressor can get all input data available so far. (In particular
00234 avail_in is zero after the call if enough output space has been provided
00235 before the call.) Flushing may degrade compression for some compression
00236 algorithms and so it should be used only when necessary.
00237
00238 If flush is set to Z_FULL_FLUSH, all output is flushed as with
00239 Z_SYNC_FLUSH, and the compression state is reset so that decompression can
00240 restart from this point if previous compressed data has been damaged or if
00241 random access is desired. Using Z_FULL_FLUSH too often can seriously degrade
00242 the compression.
00243
00244 If deflate returns with avail_out == 0, this function must be called again
00245 with the same value of the flush parameter and more output space (updated
00246 avail_out), until the flush is complete (deflate returns with non-zero
00247 avail_out).
00248
00249 If the parameter flush is set to Z_FINISH, pending input is processed,
00250 pending output is flushed and deflate returns with Z_STREAM_END if there
00251 was enough output space; if deflate returns with Z_OK, this function must be
00252 called again with Z_FINISH and more output space (updated avail_out) but no
00253 more input data, until it returns with Z_STREAM_END or an error. After
00254 deflate has returned Z_STREAM_END, the only possible operations on the
00255 stream are deflateReset or deflateEnd.
00256
00257 Z_FINISH can be used immediately after deflateInit if all the compression
00258 is to be done in a single step. In this case, avail_out must be at least
00259 0.1% larger than avail_in plus 12 bytes. If deflate does not return
00260 Z_STREAM_END, then it must be called again as described above.
00261
00262 deflate() sets strm->adler to the adler32 checksum of all input read
00263 so far (that is, total_in bytes).
00264
00265 deflate() may update data_type if it can make a good guess about
00266 the input data type (Z_ASCII or Z_BINARY). In doubt, the data is considered
00267 binary. This field is only for information purposes and does not affect
00268 the compression algorithm in any manner.
00269
00270 deflate() returns Z_OK if some progress has been made (more input
00271 processed or more output produced), Z_STREAM_END if all input has been
00272 consumed and all output has been produced (only when flush is set to
00273 Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
00274 if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible
00275 (for example avail_in or avail_out was zero).
00276 */
00277
00278
00279 ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm));
00280 /*
00281 All dynamically allocated data structures for this stream are freed.
00282 This function discards any unprocessed input and does not flush any
00283 pending output.
00284
00285 deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
00286 stream state was inconsistent, Z_DATA_ERROR if the stream was freed
00287 prematurely (some input or output was discarded). In the error case,
00288 msg may be set but then points to a static string (which must not be
00289 deallocated).
00290 */
00291
00292
00293 /*
00294 ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm));
00295
00296 Initializes the internal stream state for decompression. The fields
00297 next_in, avail_in, zalloc, zfree and opaque must be initialized before by
00298 the caller. If next_in is not Z_NULL and avail_in is large enough (the exact
00299 value depends on the compression method), inflateInit determines the
00300 compression method from the zlib header and allocates all data structures
00301 accordingly; otherwise the allocation will be deferred to the first call of
00302 inflate. If zalloc and zfree are set to Z_NULL, inflateInit updates them to
00303 use default allocation functions.
00304
00305 inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
00306 memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
00307 version assumed by the caller. msg is set to null if there is no error
00308 message. inflateInit does not perform any decompression apart from reading
00309 the zlib header if present: this will be done by inflate(). (So next_in and
00310 avail_in may be modified, but next_out and avail_out are unchanged.)
00311 */
00312
00313
00314 ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush));
00315 /*
00316 inflate decompresses as much data as possible, and stops when the input
00317 buffer becomes empty or the output buffer becomes full. It may some
00318 introduce some output latency (reading input without producing any output)
00319 except when forced to flush.
00320
00321 The detailed semantics are as follows. inflate performs one or both of the
00322 following actions:
00323
00324 - Decompress more input starting at next_in and update next_in and avail_in
00325 accordingly. If not all input can be processed (because there is not
00326 enough room in the output buffer), next_in is updated and processing
00327 will resume at this point for the next call of inflate().
00328
00329 - Provide more output starting at next_out and update next_out and avail_out
00330 accordingly. inflate() provides as much output as possible, until there
00331 is no more input data or no more space in the output buffer (see below
00332 about the flush parameter).
00333
00334 Before the call of inflate(), the application should ensure that at least
00335 one of the actions is possible, by providing more input and/or consuming
00336 more output, and updating the next_* and avail_* values accordingly.
00337 The application can consume the uncompressed output when it wants, for
00338 example when the output buffer is full (avail_out == 0), or after each
00339 call of inflate(). If inflate returns Z_OK and with zero avail_out, it
00340 must be called again after making room in the output buffer because there
00341 might be more output pending.
00342
00343 If the parameter flush is set to Z_SYNC_FLUSH, inflate flushes as much
00344 output as possible to the output buffer. The flushing behavior of inflate is
00345 not specified for values of the flush parameter other than Z_SYNC_FLUSH
00346 and Z_FINISH, but the current implementation actually flushes as much output
00347 as possible anyway.
00348
00349 inflate() should normally be called until it returns Z_STREAM_END or an
00350 error. However if all decompression is to be performed in a single step
00351 (a single call of inflate), the parameter flush should be set to
00352 Z_FINISH. In this case all pending input is processed and all pending
00353 output is flushed; avail_out must be large enough to hold all the
00354 uncompressed data. (The size of the uncompressed data may have been saved
00355 by the compressor for this purpose.) The next operation on this stream must
00356 be inflateEnd to deallocate the decompression state. The use of Z_FINISH
00357 is never required, but can be used to inform inflate that a faster routine
00358 may be used for the single inflate() call.
00359
00360 If a preset dictionary is needed at this point (see inflateSetDictionary
00361 below), inflate sets strm-adler to the adler32 checksum of the
00362 dictionary chosen by the compressor and returns Z_NEED_DICT; otherwise
00363 it sets strm->adler to the adler32 checksum of all output produced
00364 so far (that is, total_out bytes) and returns Z_OK, Z_STREAM_END or
00365 an error code as described below. At the end of the stream, inflate()
00366 checks that its computed adler32 checksum is equal to that saved by the
00367 compressor and returns Z_STREAM_END only if the checksum is correct.
00368
00369 inflate() returns Z_OK if some progress has been made (more input processed
00370 or more output produced), Z_STREAM_END if the end of the compressed data has
00371 been reached and all uncompressed output has been produced, Z_NEED_DICT if a
00372 preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
00373 corrupted (input stream not conforming to the zlib format or incorrect
00374 adler32 checksum), Z_STREAM_ERROR if the stream structure was inconsistent
00375 (for example if next_in or next_out was NULL), Z_MEM_ERROR if there was not
00376 enough memory, Z_BUF_ERROR if no progress is possible or if there was not
00377 enough room in the output buffer when Z_FINISH is used. In the Z_DATA_ERROR
00378 case, the application may then call inflateSync to look for a good
00379 compression block.
00380 */
00381
00382
00383 ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm));
00384 /*
00385 All dynamically allocated data structures for this stream are freed.
00386 This function discards any unprocessed input and does not flush any
00387 pending output.
00388
00389 inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state
00390 was inconsistent. In the error case, msg may be set but then points to a
00391 static string (which must not be deallocated).
00392 */
00393
00394 /* Advanced functions */
00395
00396 /*
00397 The following functions are needed only in some special applications.
00398 */
00399
00400 /*
00401 ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm,
00402 int level,
00403 int method,
00404 int windowBits,
00405 int memLevel,
00406 int strategy));
00407
00408 This is another version of deflateInit with more compression options. The
00409 fields next_in, zalloc, zfree and opaque must be initialized before by
00410 the caller.
00411
00412 The method parameter is the compression method. It must be Z_DEFLATED in
00413 this version of the library.
00414
00415 The windowBits parameter is the base two logarithm of the window size
00416 (the size of the history buffer). It should be in the range 8..15 for this
00417 version of the library. Larger values of this parameter result in better
00418 compression at the expense of memory usage. The default value is 15 if
00419 deflateInit is used instead.
00420
00421 The memLevel parameter specifies how much memory should be allocated
00422 for the internal compression state. memLevel=1 uses minimum memory but
00423 is slow and reduces compression ratio; memLevel=9 uses maximum memory
00424 for optimal speed. The default value is 8. See zconf.h for total memory
00425 usage as a function of windowBits and memLevel.
00426
00427 The strategy parameter is used to tune the compression algorithm. Use the
00428 value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
00429 filter (or predictor), or Z_HUFFMAN_ONLY to force Huffman encoding only (no
00430 string match). Filtered data consists mostly of small values with a
00431 somewhat random distribution. In this case, the compression algorithm is
00432 tuned to compress them better. The effect of Z_FILTERED is to force more
00433 Huffman coding and less string matching; it is somewhat intermediate
00434 between Z_DEFAULT and Z_HUFFMAN_ONLY. The strategy parameter only affects
00435 the compression ratio but not the correctness of the compressed output even
00436 if it is not set appropriately.
00437
00438 deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
00439 memory, Z_STREAM_ERROR if a parameter is invalid (such as an invalid
00440 method). msg is set to null if there is no error message. deflateInit2 does
00441 not perform any compression: this will be done by deflate().
00442 */
00443
00444 ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm,
00445 const Bytef *dictionary,
00446 uInt dictLength));
00447 /*
00448 Initializes the compression dictionary from the given byte sequence
00449 without producing any compressed output. This function must be called
00450 immediately after deflateInit, deflateInit2 or deflateReset, before any
00451 call of deflate. The compressor and decompressor must use exactly the same
00452 dictionary (see inflateSetDictionary).
00453
00454 The dictionary should consist of strings (byte sequences) that are likely
00455 to be encountered later in the data to be compressed, with the most commonly
00456 used strings preferably put towards the end of the dictionary. Using a
00457 dictionary is most useful when the data to be compressed is short and can be
00458 predicted with good accuracy; the data can then be compressed better than
00459 with the default empty dictionary.
00460
00461 Depending on the size of the compression data structures selected by
00462 deflateInit or deflateInit2, a part of the dictionary may in effect be
00463 discarded, for example if the dictionary is larger than the window size in
00464 deflate or deflate2. Thus the strings most likely to be useful should be
00465 put at the end of the dictionary, not at the front.
00466
00467 Upon return of this function, strm->adler is set to the Adler32 value
00468 of the dictionary; the decompressor may later use this value to determine
00469 which dictionary has been used by the compressor. (The Adler32 value
00470 applies to the whole dictionary even if only a subset of the dictionary is
00471 actually used by the compressor.)
00472
00473 deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
00474 parameter is invalid (such as NULL dictionary) or the stream state is
00475 inconsistent (for example if deflate has already been called for this stream
00476 or if the compression method is bsort). deflateSetDictionary does not
00477 perform any compression: this will be done by deflate().
00478 */
00479
00480 ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest,
00481 z_streamp source));
00482 /*
00483 Sets the destination stream as a complete copy of the source stream.
00484
00485 This function can be useful when several compression strategies will be
00486 tried, for example when there are several ways of pre-processing the input
00487 data with a filter. The streams that will be discarded should then be freed
00488 by calling deflateEnd. Note that deflateCopy duplicates the internal
00489 compression state which can be quite large, so this strategy is slow and
00490 can consume lots of memory.
00491
00492 deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
00493 enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
00494 (such as zalloc being NULL). msg is left unchanged in both source and
00495 destination.
00496 */
00497
00498 ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm));
00499 /*
00500 This function is equivalent to deflateEnd followed by deflateInit,
00501 but does not free and reallocate all the internal compression state.
00502 The stream will keep the same compression level and any other attributes
00503 that may have been set by deflateInit2.
00504
00505 deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
00506 stream state was inconsistent (such as zalloc or state being NULL).
00507 */
00508
00509 ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm,
00510 int level,
00511 int strategy));
00512 /*
00513 Dynamically update the compression level and compression strategy. The
00514 interpretation of level and strategy is as in deflateInit2. This can be
00515 used to switch between compression and straight copy of the input data, or
00516 to switch to a different kind of input data requiring a different
00517 strategy. If the compression level is changed, the input available so far
00518 is compressed with the old level (and may be flushed); the new level will
00519 take effect only at the next call of deflate().
00520
00521 Before the call of deflateParams, the stream state must be set as for
00522 a call of deflate(), since the currently available input may have to
00523 be compressed and flushed. In particular, strm->avail_out must be non-zero.
00524
00525 deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source
00526 stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR
00527 if strm->avail_out was zero.
00528 */
00529
00530 /*
00531 ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm,
00532 int windowBits));
00533
00534 This is another version of inflateInit with an extra parameter. The
00535 fields next_in, avail_in, zalloc, zfree and opaque must be initialized
00536 before by the caller.
00537
00538 The windowBits parameter is the base two logarithm of the maximum window
00539 size (the size of the history buffer). It should be in the range 8..15 for
00540 this version of the library. The default value is 15 if inflateInit is used
00541 instead. If a compressed stream with a larger window size is given as
00542 input, inflate() will return with the error code Z_DATA_ERROR instead of
00543 trying to allocate a larger window.
00544
00545 inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
00546 memory, Z_STREAM_ERROR if a parameter is invalid (such as a negative
00547 memLevel). msg is set to null if there is no error message. inflateInit2
00548 does not perform any decompression apart from reading the zlib header if
00549 present: this will be done by inflate(). (So next_in and avail_in may be
00550 modified, but next_out and avail_out are unchanged.)
00551 */
00552
00553 ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm,
00554 const Bytef *dictionary,
00555 uInt dictLength));
00556 /*
00557 Initializes the decompression dictionary from the given uncompressed byte
00558 sequence. This function must be called immediately after a call of inflate
00559 if this call returned Z_NEED_DICT. The dictionary chosen by the compressor
00560 can be determined from the Adler32 value returned by this call of
00561 inflate. The compressor and decompressor must use exactly the same
00562 dictionary (see deflateSetDictionary).
00563
00564 inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
00565 parameter is invalid (such as NULL dictionary) or the stream state is
00566 inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
00567 expected one (incorrect Adler32 value). inflateSetDictionary does not
00568 perform any decompression: this will be done by subsequent calls of
00569 inflate().
00570 */
00571
00572 ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm));
00573 /*
00574 Skips invalid compressed data until a full flush point (see above the
00575 description of deflate with Z_FULL_FLUSH) can be found, or until all
00576 available input is skipped. No output is provided.
00577
00578 inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR
00579 if no more input was provided, Z_DATA_ERROR if no flush point has been found,
00580 or Z_STREAM_ERROR if the stream structure was inconsistent. In the success
00581 case, the application may save the current current value of total_in which
00582 indicates where valid compressed data was found. In the error case, the
00583 application may repeatedly call inflateSync, providing more input each time,
00584 until success or end of the input data.
00585 */
00586
00587 ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm));
00588 /*
00589 This function is equivalent to inflateEnd followed by inflateInit,
00590 but does not free and reallocate all the internal decompression state.
00591 The stream will keep attributes that may have been set by inflateInit2.
00592
00593 inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
00594 stream state was inconsistent (such as zalloc or state being NULL).
00595 */
00596
00597
00598 /* utility functions */
00599
00600 /*
00601 The following utility functions are implemented on top of the
00602 basic stream-oriented functions. To simplify the interface, some
00603 default options are assumed (compression level and memory usage,
00604 standard memory allocation functions). The source code of these
00605 utility functions can easily be modified if you need special options.
00606 */
00607
00608 ZEXTERN int ZEXPORT compress OF((Bytef *dest, uLongf *destLen,
00609 const Bytef *source, uLong sourceLen));
00610 /*
00611 Compresses the source buffer into the destination buffer. sourceLen is
00612 the byte length of the source buffer. Upon entry, destLen is the total
00613 size of the destination buffer, which must be at least 0.1% larger than
00614 sourceLen plus 12 bytes. Upon exit, destLen is the actual size of the
00615 compressed buffer.
00616 This function can be used to compress a whole file at once if the
00617 input file is mmap'ed.
00618 compress returns Z_OK if success, Z_MEM_ERROR if there was not
00619 enough memory, Z_BUF_ERROR if there was not enough room in the output
00620 buffer.
00621 */
00622
00623 ZEXTERN int ZEXPORT compress2 OF((Bytef *dest, uLongf *destLen,
00624 const Bytef *source, uLong sourceLen,
00625 int level));
00626 /*
00627 Compresses the source buffer into the destination buffer. The level
00628 parameter has the same meaning as in deflateInit. sourceLen is the byte
00629 length of the source buffer. Upon entry, destLen is the total size of the
00630 destination buffer, which must be at least 0.1% larger than sourceLen plus
00631 12 bytes. Upon exit, destLen is the actual size of the compressed buffer.
00632
00633 compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
00634 memory, Z_BUF_ERROR if there was not enough room in the output buffer,
00635 Z_STREAM_ERROR if the level parameter is invalid.
00636 */
00637
00638 ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen,
00639 const Bytef *source, uLong sourceLen));
00640 /*
00641 Decompresses the source buffer into the destination buffer. sourceLen is
00642 the byte length of the source buffer. Upon entry, destLen is the total
00643 size of the destination buffer, which must be large enough to hold the
00644 entire uncompressed data. (The size of the uncompressed data must have
00645 been saved previously by the compressor and transmitted to the decompressor
00646 by some mechanism outside the scope of this compression library.)
00647 Upon exit, destLen is the actual size of the compressed buffer.
00648 This function can be used to decompress a whole file at once if the
00649 input file is mmap'ed.
00650
00651 uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
00652 enough memory, Z_BUF_ERROR if there was not enough room in the output
00653 buffer, or Z_DATA_ERROR if the input data was corrupted.
00654 */
00655
00656
00657 typedef voidp gzFile;
00658
00659 ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode));
00660 /*
00661 Opens a gzip (.gz) file for reading or writing. The mode parameter
00662 is as in fopen ("rb" or "wb") but can also include a compression level
00663 ("wb9") or a strategy: 'f' for filtered data as in "wb6f", 'h' for
00664 Huffman only compression as in "wb1h". (See the description
00665 of deflateInit2 for more information about the strategy parameter.)
00666
00667 gzopen can be used to read a file which is not in gzip format; in this
00668 case gzread will directly read from the file without decompression.
00669
00670 gzopen returns NULL if the file could not be opened or if there was
00671 insufficient memory to allocate the (de)compression state; errno
00672 can be checked to distinguish the two cases (if errno is zero, the
00673 zlib error is Z_MEM_ERROR). */
00674
00675 ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode));
00676 /*
00677 gzdopen() associates a gzFile with the file descriptor fd. File
00678 descriptors are obtained from calls like open, dup, creat, pipe or
00679 fileno (in the file has been previously opened with fopen).
00680 The mode parameter is as in gzopen.
00681 The next call of gzclose on the returned gzFile will also close the
00682 file descriptor fd, just like fclose(fdopen(fd), mode) closes the file
00683 descriptor fd. If you want to keep fd open, use gzdopen(dup(fd), mode).
00684 gzdopen returns NULL if there was insufficient memory to allocate
00685 the (de)compression state.
00686 */
00687
00688 ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy));
00689 /*
00690 Dynamically update the compression level or strategy. See the description
00691 of deflateInit2 for the meaning of these parameters.
00692 gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not
00693 opened for writing.
00694 */
00695
00696 ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len));
00697 /*
00698 Reads the given number of uncompressed bytes from the compressed file.
00699 If the input file was not in gzip format, gzread copies the given number
00700 of bytes into the buffer.
00701 gzread returns the number of uncompressed bytes actually read (0 for
00702 end of file, -1 for error). */
00703
00704 ZEXTERN int ZEXPORT gzwrite OF((gzFile file,
00705 const voidp buf, unsigned len));
00706 /*
00707 Writes the given number of uncompressed bytes into the compressed file.
00708 gzwrite returns the number of uncompressed bytes actually written
00709 (0 in case of error).
00710 */
00711
00712 ZEXTERN int ZEXPORTVA gzprintf OF((gzFile file, const char *format, ...));
00713 /*
00714 Converts, formats, and writes the args to the compressed file under
00715 control of the format string, as in fprintf. gzprintf returns the number of
00716 uncompressed bytes actually written (0 in case of error).
00717 */
00718
00719 ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s));
00720 /*
00721 Writes the given null-terminated string to the compressed file, excluding
00722 the terminating null character.
00723 gzputs returns the number of characters written, or -1 in case of error.
00724 */
00725
00726 ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len));
00727 /*
00728 Reads bytes from the compressed file until len-1 characters are read, or
00729 a newline character is read and transferred to buf, or an end-of-file
00730 condition is encountered. The string is then terminated with a null
00731 character.
00732 gzgets returns buf, or Z_NULL in case of error.
00733 */
00734
00735 ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c));
00736 /*
00737 Writes c, converted to an unsigned char, into the compressed file.
00738 gzputc returns the value that was written, or -1 in case of error.
00739 */
00740
00741 ZEXTERN int ZEXPORT gzgetc OF((gzFile file));
00742 /*
00743 Reads one byte from the compressed file. gzgetc returns this byte
00744 or -1 in case of end of file or error.
00745 */
00746
00747 ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush));
00748 /*
00749 Flushes all pending output into the compressed file. The parameter
00750 flush is as in the deflate() function. The return value is the zlib
00751 error number (see function gzerror below). gzflush returns Z_OK if
00752 the flush parameter is Z_FINISH and all output could be flushed.
00753 gzflush should be called only when strictly necessary because it can
00754 degrade compression.
00755 */
00756
00757 ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file,
00758 z_off_t offset, int whence));
00759 /*
00760 Sets the starting position for the next gzread or gzwrite on the
00761 given compressed file. The offset represents a number of bytes in the
00762 uncompressed data stream. The whence parameter is defined as in lseek(2);
00763 the value SEEK_END is not supported.
00764 If the file is opened for reading, this function is emulated but can be
00765 extremely slow. If the file is opened for writing, only forward seeks are
00766 supported; gzseek then compresses a sequence of zeroes up to the new
00767 starting position.
00768
00769 gzseek returns the resulting offset location as measured in bytes from
00770 the beginning of the uncompressed stream, or -1 in case of error, in
00771 particular if the file is opened for writing and the new starting position
00772 would be before the current position.
00773 */
00774
00775 ZEXTERN int ZEXPORT gzrewind OF((gzFile file));
00776 /*
00777 Rewinds the given file. This function is supported only for reading.
00778
00779 gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET)
00780 */
00781
00782 ZEXTERN z_off_t ZEXPORT gztell OF((gzFile file));
00783 /*
00784 Returns the starting position for the next gzread or gzwrite on the
00785 given compressed file. This position represents a number of bytes in the
00786 uncompressed data stream.
00787
00788 gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)
00789 */
00790
00791 ZEXTERN int ZEXPORT gzeof OF((gzFile file));
00792 /*
00793 Returns 1 when EOF has previously been detected reading the given
00794 input stream, otherwise zero.
00795 */
00796
00797 ZEXTERN int ZEXPORT gzclose OF((gzFile file));
00798 /*
00799 Flushes all pending output if necessary, closes the compressed file
00800 and deallocates all the (de)compression state. The return value is the zlib
00801 error number (see function gzerror below).
00802 */
00803
00804 ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum));
00805 /*
00806 Returns the error message for the last error which occurred on the
00807 given compressed file. errnum is set to zlib error number. If an
00808 error occurred in the file system and not in the compression library,
00809 errnum is set to Z_ERRNO and the application may consult errno
00810 to get the exact error code.
00811 */
00812
00813 /* checksum functions */
00814
00815 /*
00816 These functions are not related to compression but are exported
00817 anyway because they might be useful in applications using the
00818 compression library.
00819 */
00820
00821 ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len));
00822
00823 /*
00824 Update a running Adler-32 checksum with the bytes buf[0..len-1] and
00825 return the updated checksum. If buf is NULL, this function returns
00826 the required initial value for the checksum.
00827 An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
00828 much faster. Usage example:
00829
00830 uLong adler = adler32(0L, Z_NULL, 0);
00831
00832 while (read_buffer(buffer, length) != EOF) {
00833 adler = adler32(adler, buffer, length);
00834 }
00835 if (adler != original_adler) error();
00836 */
00837
00838 ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len));
00839 /*
00840 Update a running crc with the bytes buf[0..len-1] and return the updated
00841 crc. If buf is NULL, this function returns the required initial value
00842 for the crc. Pre- and post-conditioning (one's complement) is performed
00843 within this function so it shouldn't be done by the application.
00844 Usage example:
00845
00846 uLong crc = crc32(0L, Z_NULL, 0);
00847
00848 while (read_buffer(buffer, length) != EOF) {
00849 crc = crc32(crc, buffer, length);
00850 }
00851 if (crc != original_crc) error();
00852 */
00853
00854
00855 /* various hacks, don't look :) */
00856
00857 /* deflateInit and inflateInit are macros to allow checking the zlib version
00858 * and the compiler's view of z_stream:
00859 */
00860 ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level,
00861 const char *version, int stream_size));
00862 ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm,
00863 const char *version, int stream_size));
00864 ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method,
00865 int windowBits, int memLevel,
00866 int strategy, const char *version,
00867 int stream_size));
00868 ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits,
00869 const char *version, int stream_size));
00870 #define deflateInit(strm, level) \
00871 deflateInit_((strm), (level), ZLIB_VERSION, sizeof(z_stream))
00872 #define inflateInit(strm) \
00873 inflateInit_((strm), ZLIB_VERSION, sizeof(z_stream))
00874 #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
00875 deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
00876 (strategy), ZLIB_VERSION, sizeof(z_stream))
00877 #define inflateInit2(strm, windowBits) \
00878 inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream))
00879
00880
00881 #if !defined(_Z_UTIL_H) && !defined(NO_DUMMY_DECL)
00882 struct internal_state {int dummy;}; /* hack for buggy compilers */
00883 #endif
00884
00885 ZEXTERN const char * ZEXPORT zError OF((int err));
00886 ZEXTERN int ZEXPORT inflateSyncPoint OF((z_streamp z));
00887 ZEXTERN const uLongf * ZEXPORT get_crc_table OF((void));
00888
00889 #ifdef __cplusplus
00890 }
00891 #endif
00892
00893 #endif /* _ZLIB_H */
1.1.5 written by Dimitri van Heesch,
© 1997-2000