Annotation of libwww/Library/External/zlib.h, revision 1.1
1.1 ! frystyk 1: /* zlib.h -- interface of the 'zlib' general purpose compression library
! 2: version 1.1.2, March 19th, 1998
! 3:
! 4: Copyright (C) 1995-1998 Jean-loup Gailly and Mark Adler
! 5:
! 6: This software is provided 'as-is', without any express or implied
! 7: warranty. In no event will the authors be held liable for any damages
! 8: arising from the use of this software.
! 9:
! 10: Permission is granted to anyone to use this software for any purpose,
! 11: including commercial applications, and to alter it and redistribute it
! 12: freely, subject to the following restrictions:
! 13:
! 14: 1. The origin of this software must not be misrepresented; you must not
! 15: claim that you wrote the original software. If you use this software
! 16: in a product, an acknowledgment in the product documentation would be
! 17: appreciated but is not required.
! 18: 2. Altered source versions must be plainly marked as such, and must not be
! 19: misrepresented as being the original software.
! 20: 3. This notice may not be removed or altered from any source distribution.
! 21:
! 22: Jean-loup Gailly Mark Adler
! 23: jloup@gzip.org madler@alumni.caltech.edu
! 24:
! 25:
! 26: The data format used by the zlib library is described by RFCs (Request for
! 27: Comments) 1950 to 1952 in the files ftp://ds.internic.net/rfc/rfc1950.txt
! 28: (zlib format), rfc1951.txt (deflate format) and rfc1952.txt (gzip format).
! 29: */
! 30:
! 31: #ifndef _ZLIB_H
! 32: #define _ZLIB_H
! 33:
! 34: #include "zconf.h"
! 35:
! 36: #ifdef __cplusplus
! 37: extern "C" {
! 38: #endif
! 39:
! 40: #define ZLIB_VERSION "1.1.2"
! 41:
! 42: /*
! 43: The 'zlib' compression library provides in-memory compression and
! 44: decompression functions, including integrity checks of the uncompressed
! 45: data. This version of the library supports only one compression method
! 46: (deflation) but other algorithms will be added later and will have the same
! 47: stream interface.
! 48:
! 49: Compression can be done in a single step if the buffers are large
! 50: enough (for example if an input file is mmap'ed), or can be done by
! 51: repeated calls of the compression function. In the latter case, the
! 52: application must provide more input and/or consume the output
! 53: (providing more output space) before each call.
! 54:
! 55: The library also supports reading and writing files in gzip (.gz) format
! 56: with an interface similar to that of stdio.
! 57:
! 58: The library does not install any signal handler. The decoder checks
! 59: the consistency of the compressed data, so the library should never
! 60: crash even in case of corrupted input.
! 61: */
! 62:
! 63: typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size));
! 64: typedef void (*free_func) OF((voidpf opaque, voidpf address));
! 65:
! 66: struct internal_state;
! 67:
! 68: typedef struct z_stream_s {
! 69: Bytef *next_in; /* next input byte */
! 70: uInt avail_in; /* number of bytes available at next_in */
! 71: uLong total_in; /* total nb of input bytes read so far */
! 72:
! 73: Bytef *next_out; /* next output byte should be put there */
! 74: uInt avail_out; /* remaining free space at next_out */
! 75: uLong total_out; /* total nb of bytes output so far */
! 76:
! 77: char *msg; /* last error message, NULL if no error */
! 78: struct internal_state FAR *state; /* not visible by applications */
! 79:
! 80: alloc_func zalloc; /* used to allocate the internal state */
! 81: free_func zfree; /* used to free the internal state */
! 82: voidpf opaque; /* private data object passed to zalloc and zfree */
! 83:
! 84: int data_type; /* best guess about the data type: ascii or binary */
! 85: uLong adler; /* adler32 value of the uncompressed data */
! 86: uLong reserved; /* reserved for future use */
! 87: } z_stream;
! 88:
! 89: typedef z_stream FAR *z_streamp;
! 90:
! 91: /*
! 92: The application must update next_in and avail_in when avail_in has
! 93: dropped to zero. It must update next_out and avail_out when avail_out
! 94: has dropped to zero. The application must initialize zalloc, zfree and
! 95: opaque before calling the init function. All other fields are set by the
! 96: compression library and must not be updated by the application.
! 97:
! 98: The opaque value provided by the application will be passed as the first
! 99: parameter for calls of zalloc and zfree. This can be useful for custom
! 100: memory management. The compression library attaches no meaning to the
! 101: opaque value.
! 102:
! 103: zalloc must return Z_NULL if there is not enough memory for the object.
! 104: If zlib is used in a multi-threaded application, zalloc and zfree must be
! 105: thread safe.
! 106:
! 107: On 16-bit systems, the functions zalloc and zfree must be able to allocate
! 108: exactly 65536 bytes, but will not be required to allocate more than this
! 109: if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS,
! 110: pointers returned by zalloc for objects of exactly 65536 bytes *must*
! 111: have their offset normalized to zero. The default allocation function
! 112: provided by this library ensures this (see zutil.c). To reduce memory
! 113: requirements and avoid any allocation of 64K objects, at the expense of
! 114: compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h).
! 115:
! 116: The fields total_in and total_out can be used for statistics or
! 117: progress reports. After compression, total_in holds the total size of
! 118: the uncompressed data and may be saved for use in the decompressor
! 119: (particularly if the decompressor wants to decompress everything in
! 120: a single step).
! 121: */
! 122:
! 123: /* constants */
! 124:
! 125: #define Z_NO_FLUSH 0
! 126: #define Z_PARTIAL_FLUSH 1 /* will be removed, use Z_SYNC_FLUSH instead */
! 127: #define Z_SYNC_FLUSH 2
! 128: #define Z_FULL_FLUSH 3
! 129: #define Z_FINISH 4
! 130: /* Allowed flush values; see deflate() below for details */
! 131:
! 132: #define Z_OK 0
! 133: #define Z_STREAM_END 1
! 134: #define Z_NEED_DICT 2
! 135: #define Z_ERRNO (-1)
! 136: #define Z_STREAM_ERROR (-2)
! 137: #define Z_DATA_ERROR (-3)
! 138: #define Z_MEM_ERROR (-4)
! 139: #define Z_BUF_ERROR (-5)
! 140: #define Z_VERSION_ERROR (-6)
! 141: /* Return codes for the compression/decompression functions. Negative
! 142: * values are errors, positive values are used for special but normal events.
! 143: */
! 144:
! 145: #define Z_NO_COMPRESSION 0
! 146: #define Z_BEST_SPEED 1
! 147: #define Z_BEST_COMPRESSION 9
! 148: #define Z_DEFAULT_COMPRESSION (-1)
! 149: /* compression levels */
! 150:
! 151: #define Z_FILTERED 1
! 152: #define Z_HUFFMAN_ONLY 2
! 153: #define Z_DEFAULT_STRATEGY 0
! 154: /* compression strategy; see deflateInit2() below for details */
! 155:
! 156: #define Z_BINARY 0
! 157: #define Z_ASCII 1
! 158: #define Z_UNKNOWN 2
! 159: /* Possible values of the data_type field */
! 160:
! 161: #define Z_DEFLATED 8
! 162: /* The deflate compression method (the only one supported in this version) */
! 163:
! 164: #define Z_NULL 0 /* for initializing zalloc, zfree, opaque */
! 165:
! 166: #define zlib_version zlibVersion()
! 167: /* for compatibility with versions < 1.0.2 */
! 168:
! 169: /* basic functions */
! 170:
! 171: extern const char * ZEXPORT zlibVersion OF((void));
! 172: /* The application can compare zlibVersion and ZLIB_VERSION for consistency.
! 173: If the first character differs, the library code actually used is
! 174: not compatible with the zlib.h header file used by the application.
! 175: This check is automatically made by deflateInit and inflateInit.
! 176: */
! 177:
! 178: /*
! 179: extern int ZEXPORT deflateInit OF((z_streamp strm, int level));
! 180:
! 181: Initializes the internal stream state for compression. The fields
! 182: zalloc, zfree and opaque must be initialized before by the caller.
! 183: If zalloc and zfree are set to Z_NULL, deflateInit updates them to
! 184: use default allocation functions.
! 185:
! 186: The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
! 187: 1 gives best speed, 9 gives best compression, 0 gives no compression at
! 188: all (the input data is simply copied a block at a time).
! 189: Z_DEFAULT_COMPRESSION requests a default compromise between speed and
! 190: compression (currently equivalent to level 6).
! 191:
! 192: deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not
! 193: enough memory, Z_STREAM_ERROR if level is not a valid compression level,
! 194: Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
! 195: with the version assumed by the caller (ZLIB_VERSION).
! 196: msg is set to null if there is no error message. deflateInit does not
! 197: perform any compression: this will be done by deflate().
! 198: */
! 199:
! 200:
! 201: extern int ZEXPORT deflate OF((z_streamp strm, int flush));
! 202: /*
! 203: deflate compresses as much data as possible, and stops when the input
! 204: buffer becomes empty or the output buffer becomes full. It may introduce some
! 205: output latency (reading input without producing any output) except when
! 206: forced to flush.
! 207:
! 208: The detailed semantics are as follows. deflate performs one or both of the
! 209: following actions:
! 210:
! 211: - Compress more input starting at next_in and update next_in and avail_in
! 212: accordingly. If not all input can be processed (because there is not
! 213: enough room in the output buffer), next_in and avail_in are updated and
! 214: processing will resume at this point for the next call of deflate().
! 215:
! 216: - Provide more output starting at next_out and update next_out and avail_out
! 217: accordingly. This action is forced if the parameter flush is non zero.
! 218: Forcing flush frequently degrades the compression ratio, so this parameter
! 219: should be set only when necessary (in interactive applications).
! 220: Some output may be provided even if flush is not set.
! 221:
! 222: Before the call of deflate(), the application should ensure that at least
! 223: one of the actions is possible, by providing more input and/or consuming
! 224: more output, and updating avail_in or avail_out accordingly; avail_out
! 225: should never be zero before the call. The application can consume the
! 226: compressed output when it wants, for example when the output buffer is full
! 227: (avail_out == 0), or after each call of deflate(). If deflate returns Z_OK
! 228: and with zero avail_out, it must be called again after making room in the
! 229: output buffer because there might be more output pending.
! 230:
! 231: If the parameter flush is set to Z_SYNC_FLUSH, all pending output is
! 232: flushed to the output buffer and the output is aligned on a byte boundary, so
! 233: that the decompressor can get all input data available so far. (In particular
! 234: avail_in is zero after the call if enough output space has been provided
! 235: before the call.) Flushing may degrade compression for some compression
! 236: algorithms and so it should be used only when necessary.
! 237:
! 238: If flush is set to Z_FULL_FLUSH, all output is flushed as with
! 239: Z_SYNC_FLUSH, and the compression state is reset so that decompression can
! 240: restart from this point if previous compressed data has been damaged or if
! 241: random access is desired. Using Z_FULL_FLUSH too often can seriously degrade
! 242: the compression.
! 243:
! 244: If deflate returns with avail_out == 0, this function must be called again
! 245: with the same value of the flush parameter and more output space (updated
! 246: avail_out), until the flush is complete (deflate returns with non-zero
! 247: avail_out).
! 248:
! 249: If the parameter flush is set to Z_FINISH, pending input is processed,
! 250: pending output is flushed and deflate returns with Z_STREAM_END if there
! 251: was enough output space; if deflate returns with Z_OK, this function must be
! 252: called again with Z_FINISH and more output space (updated avail_out) but no
! 253: more input data, until it returns with Z_STREAM_END or an error. After
! 254: deflate has returned Z_STREAM_END, the only possible operations on the
! 255: stream are deflateReset or deflateEnd.
! 256:
! 257: Z_FINISH can be used immediately after deflateInit if all the compression
! 258: is to be done in a single step. In this case, avail_out must be at least
! 259: 0.1% larger than avail_in plus 12 bytes. If deflate does not return
! 260: Z_STREAM_END, then it must be called again as described above.
! 261:
! 262: deflate() sets strm->adler to the adler32 checksum of all input read
! 263: so far (that is, total_in bytes).
! 264:
! 265: deflate() may update data_type if it can make a good guess about
! 266: the input data type (Z_ASCII or Z_BINARY). In doubt, the data is considered
! 267: binary. This field is only for information purposes and does not affect
! 268: the compression algorithm in any manner.
! 269:
! 270: deflate() returns Z_OK if some progress has been made (more input
! 271: processed or more output produced), Z_STREAM_END if all input has been
! 272: consumed and all output has been produced (only when flush is set to
! 273: Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
! 274: if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible.
! 275: */
! 276:
! 277:
! 278: extern int ZEXPORT deflateEnd OF((z_streamp strm));
! 279: /*
! 280: All dynamically allocated data structures for this stream are freed.
! 281: This function discards any unprocessed input and does not flush any
! 282: pending output.
! 283:
! 284: deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
! 285: stream state was inconsistent, Z_DATA_ERROR if the stream was freed
! 286: prematurely (some input or output was discarded). In the error case,
! 287: msg may be set but then points to a static string (which must not be
! 288: deallocated).
! 289: */
! 290:
! 291:
! 292: /*
! 293: extern int ZEXPORT inflateInit OF((z_streamp strm));
! 294:
! 295: Initializes the internal stream state for decompression. The fields
! 296: next_in, avail_in, zalloc, zfree and opaque must be initialized before by
! 297: the caller. If next_in is not Z_NULL and avail_in is large enough (the exact
! 298: value depends on the compression method), inflateInit determines the
! 299: compression method from the zlib header and allocates all data structures
! 300: accordingly; otherwise the allocation will be deferred to the first call of
! 301: inflate. If zalloc and zfree are set to Z_NULL, inflateInit updates them to
! 302: use default allocation functions.
! 303:
! 304: inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
! 305: memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
! 306: version assumed by the caller. msg is set to null if there is no error
! 307: message. inflateInit does not perform any decompression apart from reading
! 308: the zlib header if present: this will be done by inflate(). (So next_in and
! 309: avail_in may be modified, but next_out and avail_out are unchanged.)
! 310: */
! 311:
! 312:
! 313: extern int ZEXPORT inflate OF((z_streamp strm, int flush));
! 314: /*
! 315: inflate decompresses as much data as possible, and stops when the input
! 316: buffer becomes empty or the output buffer becomes full. It may some
! 317: introduce some output latency (reading input without producing any output)
! 318: except when forced to flush.
! 319:
! 320: The detailed semantics are as follows. inflate performs one or both of the
! 321: following actions:
! 322:
! 323: - Decompress more input starting at next_in and update next_in and avail_in
! 324: accordingly. If not all input can be processed (because there is not
! 325: enough room in the output buffer), next_in is updated and processing
! 326: will resume at this point for the next call of inflate().
! 327:
! 328: - Provide more output starting at next_out and update next_out and avail_out
! 329: accordingly. inflate() provides as much output as possible, until there
! 330: is no more input data or no more space in the output buffer (see below
! 331: about the flush parameter).
! 332:
! 333: Before the call of inflate(), the application should ensure that at least
! 334: one of the actions is possible, by providing more input and/or consuming
! 335: more output, and updating the next_* and avail_* values accordingly.
! 336: The application can consume the uncompressed output when it wants, for
! 337: example when the output buffer is full (avail_out == 0), or after each
! 338: call of inflate(). If inflate returns Z_OK and with zero avail_out, it
! 339: must be called again after making room in the output buffer because there
! 340: might be more output pending.
! 341:
! 342: If the parameter flush is set to Z_SYNC_FLUSH, inflate flushes as much
! 343: output as possible to the output buffer. The flushing behavior of inflate is
! 344: not specified for values of the flush parameter other than Z_SYNC_FLUSH
! 345: and Z_FINISH, but the current implementation actually flushes as much output
! 346: as possible anyway.
! 347:
! 348: inflate() should normally be called until it returns Z_STREAM_END or an
! 349: error. However if all decompression is to be performed in a single step
! 350: (a single call of inflate), the parameter flush should be set to
! 351: Z_FINISH. In this case all pending input is processed and all pending
! 352: output is flushed; avail_out must be large enough to hold all the
! 353: uncompressed data. (The size of the uncompressed data may have been saved
! 354: by the compressor for this purpose.) The next operation on this stream must
! 355: be inflateEnd to deallocate the decompression state. The use of Z_FINISH
! 356: is never required, but can be used to inform inflate that a faster routine
! 357: may be used for the single inflate() call.
! 358:
! 359: If a preset dictionary is needed at this point (see inflateSetDictionary
! 360: below), inflate sets strm-adler to the adler32 checksum of the
! 361: dictionary chosen by the compressor and returns Z_NEED_DICT; otherwise
! 362: it sets strm->adler to the adler32 checksum of all output produced
! 363: so far (that is, total_out bytes) and returns Z_OK, Z_STREAM_END or
! 364: an error code as described below. At the end of the stream, inflate()
! 365: checks that its computed adler32 checksum is equal to that saved by the
! 366: compressor and returns Z_STREAM_END only if the checksum is correct.
! 367:
! 368: inflate() returns Z_OK if some progress has been made (more input processed
! 369: or more output produced), Z_STREAM_END if the end of the compressed data has
! 370: been reached and all uncompressed output has been produced, Z_NEED_DICT if a
! 371: preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
! 372: corrupted (input stream not conforming to the zlib format or incorrect
! 373: adler32 checksum), Z_STREAM_ERROR if the stream structure was inconsistent
! 374: (for example if next_in or next_out was NULL), Z_MEM_ERROR if there was not
! 375: enough memory, Z_BUF_ERROR if no progress is possible or if there was not
! 376: enough room in the output buffer when Z_FINISH is used. In the Z_DATA_ERROR
! 377: case, the application may then call inflateSync to look for a good
! 378: compression block.
! 379: */
! 380:
! 381:
! 382: extern int ZEXPORT inflateEnd OF((z_streamp strm));
! 383: /*
! 384: All dynamically allocated data structures for this stream are freed.
! 385: This function discards any unprocessed input and does not flush any
! 386: pending output.
! 387:
! 388: inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state
! 389: was inconsistent. In the error case, msg may be set but then points to a
! 390: static string (which must not be deallocated).
! 391: */
! 392:
! 393: /* Advanced functions */
! 394:
! 395: /*
! 396: The following functions are needed only in some special applications.
! 397: */
! 398:
! 399: /*
! 400: extern int ZEXPORT deflateInit2 OF((z_streamp strm,
! 401: int level,
! 402: int method,
! 403: int windowBits,
! 404: int memLevel,
! 405: int strategy));
! 406:
! 407: This is another version of deflateInit with more compression options. The
! 408: fields next_in, zalloc, zfree and opaque must be initialized before by
! 409: the caller.
! 410:
! 411: The method parameter is the compression method. It must be Z_DEFLATED in
! 412: this version of the library.
! 413:
! 414: The windowBits parameter is the base two logarithm of the window size
! 415: (the size of the history buffer). It should be in the range 8..15 for this
! 416: version of the library. Larger values of this parameter result in better
! 417: compression at the expense of memory usage. The default value is 15 if
! 418: deflateInit is used instead.
! 419:
! 420: The memLevel parameter specifies how much memory should be allocated
! 421: for the internal compression state. memLevel=1 uses minimum memory but
! 422: is slow and reduces compression ratio; memLevel=9 uses maximum memory
! 423: for optimal speed. The default value is 8. See zconf.h for total memory
! 424: usage as a function of windowBits and memLevel.
! 425:
! 426: The strategy parameter is used to tune the compression algorithm. Use the
! 427: value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
! 428: filter (or predictor), or Z_HUFFMAN_ONLY to force Huffman encoding only (no
! 429: string match). Filtered data consists mostly of small values with a
! 430: somewhat random distribution. In this case, the compression algorithm is
! 431: tuned to compress them better. The effect of Z_FILTERED is to force more
! 432: Huffman coding and less string matching; it is somewhat intermediate
! 433: between Z_DEFAULT and Z_HUFFMAN_ONLY. The strategy parameter only affects
! 434: the compression ratio but not the correctness of the compressed output even
! 435: if it is not set appropriately.
! 436:
! 437: deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
! 438: memory, Z_STREAM_ERROR if a parameter is invalid (such as an invalid
! 439: method). msg is set to null if there is no error message. deflateInit2 does
! 440: not perform any compression: this will be done by deflate().
! 441: */
! 442:
! 443: extern int ZEXPORT deflateSetDictionary OF((z_streamp strm,
! 444: const Bytef *dictionary,
! 445: uInt dictLength));
! 446: /*
! 447: Initializes the compression dictionary from the given byte sequence
! 448: without producing any compressed output. This function must be called
! 449: immediately after deflateInit or deflateInit2, before any call of
! 450: deflate. The compressor and decompressor must use exactly the same
! 451: dictionary (see inflateSetDictionary).
! 452:
! 453: The dictionary should consist of strings (byte sequences) that are likely
! 454: to be encountered later in the data to be compressed, with the most commonly
! 455: used strings preferably put towards the end of the dictionary. Using a
! 456: dictionary is most useful when the data to be compressed is short and can be
! 457: predicted with good accuracy; the data can then be compressed better than
! 458: with the default empty dictionary.
! 459:
! 460: Depending on the size of the compression data structures selected by
! 461: deflateInit or deflateInit2, a part of the dictionary may in effect be
! 462: discarded, for example if the dictionary is larger than the window size in
! 463: deflate or deflate2. Thus the strings most likely to be useful should be
! 464: put at the end of the dictionary, not at the front.
! 465:
! 466: Upon return of this function, strm->adler is set to the Adler32 value
! 467: of the dictionary; the decompressor may later use this value to determine
! 468: which dictionary has been used by the compressor. (The Adler32 value
! 469: applies to the whole dictionary even if only a subset of the dictionary is
! 470: actually used by the compressor.)
! 471:
! 472: deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
! 473: parameter is invalid (such as NULL dictionary) or the stream state is
! 474: inconsistent (for example if deflate has already been called for this stream
! 475: or if the compression method is bsort). deflateSetDictionary does not
! 476: perform any compression: this will be done by deflate().
! 477: */
! 478:
! 479: extern int ZEXPORT deflateCopy OF((z_streamp dest,
! 480: z_streamp source));
! 481: /*
! 482: Sets the destination stream as a complete copy of the source stream.
! 483:
! 484: This function can be useful when several compression strategies will be
! 485: tried, for example when there are several ways of pre-processing the input
! 486: data with a filter. The streams that will be discarded should then be freed
! 487: by calling deflateEnd. Note that deflateCopy duplicates the internal
! 488: compression state which can be quite large, so this strategy is slow and
! 489: can consume lots of memory.
! 490:
! 491: deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
! 492: enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
! 493: (such as zalloc being NULL). msg is left unchanged in both source and
! 494: destination.
! 495: */
! 496:
! 497: extern int ZEXPORT deflateReset OF((z_streamp strm));
! 498: /*
! 499: This function is equivalent to deflateEnd followed by deflateInit,
! 500: but does not free and reallocate all the internal compression state.
! 501: The stream will keep the same compression level and any other attributes
! 502: that may have been set by deflateInit2.
! 503:
! 504: deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
! 505: stream state was inconsistent (such as zalloc or state being NULL).
! 506: */
! 507:
! 508: extern int ZEXPORT deflateParams OF((z_streamp strm, int level, int strategy));
! 509: /*
! 510: Dynamically update the compression level and compression strategy. The
! 511: interpretation of level and strategy is as in deflateInit2. This can be
! 512: used to switch between compression and straight copy of the input data, or
! 513: to switch to a different kind of input data requiring a different
! 514: strategy. If the compression level is changed, the input available so far
! 515: is compressed with the old level (and may be flushed); the new level will
! 516: take effect only at the next call of deflate().
! 517:
! 518: Before the call of deflateParams, the stream state must be set as for
! 519: a call of deflate(), since the currently available input may have to
! 520: be compressed and flushed. In particular, strm->avail_out must be non-zero.
! 521:
! 522: deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source
! 523: stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR
! 524: if strm->avail_out was zero.
! 525: */
! 526:
! 527: /*
! 528: extern int ZEXPORT inflateInit2 OF((z_streamp strm,
! 529: int windowBits));
! 530:
! 531: This is another version of inflateInit with an extra parameter. The
! 532: fields next_in, avail_in, zalloc, zfree and opaque must be initialized
! 533: before by the caller.
! 534:
! 535: The windowBits parameter is the base two logarithm of the maximum window
! 536: size (the size of the history buffer). It should be in the range 8..15 for
! 537: this version of the library. The default value is 15 if inflateInit is used
! 538: instead. If a compressed stream with a larger window size is given as
! 539: input, inflate() will return with the error code Z_DATA_ERROR instead of
! 540: trying to allocate a larger window.
! 541:
! 542: inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
! 543: memory, Z_STREAM_ERROR if a parameter is invalid (such as a negative
! 544: memLevel). msg is set to null if there is no error message. inflateInit2
! 545: does not perform any decompression apart from reading the zlib header if
! 546: present: this will be done by inflate(). (So next_in and avail_in may be
! 547: modified, but next_out and avail_out are unchanged.)
! 548: */
! 549:
! 550: extern int ZEXPORT inflateSetDictionary OF((z_streamp strm,
! 551: const Bytef *dictionary,
! 552: uInt dictLength));
! 553: /*
! 554: Initializes the decompression dictionary from the given uncompressed byte
! 555: sequence. This function must be called immediately after a call of inflate
! 556: if this call returned Z_NEED_DICT. The dictionary chosen by the compressor
! 557: can be determined from the Adler32 value returned by this call of
! 558: inflate. The compressor and decompressor must use exactly the same
! 559: dictionary (see deflateSetDictionary).
! 560:
! 561: inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
! 562: parameter is invalid (such as NULL dictionary) or the stream state is
! 563: inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
! 564: expected one (incorrect Adler32 value). inflateSetDictionary does not
! 565: perform any decompression: this will be done by subsequent calls of
! 566: inflate().
! 567: */
! 568:
! 569: extern int ZEXPORT inflateSync OF((z_streamp strm));
! 570: /*
! 571: Skips invalid compressed data until a full flush point (see above the
! 572: description of deflate with Z_FULL_FLUSH) can be found, or until all
! 573: available input is skipped. No output is provided.
! 574:
! 575: inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR
! 576: if no more input was provided, Z_DATA_ERROR if no flush point has been found,
! 577: or Z_STREAM_ERROR if the stream structure was inconsistent. In the success
! 578: case, the application may save the current current value of total_in which
! 579: indicates where valid compressed data was found. In the error case, the
! 580: application may repeatedly call inflateSync, providing more input each time,
! 581: until success or end of the input data.
! 582: */
! 583:
! 584: extern int ZEXPORT inflateReset OF((z_streamp strm));
! 585: /*
! 586: This function is equivalent to inflateEnd followed by inflateInit,
! 587: but does not free and reallocate all the internal decompression state.
! 588: The stream will keep attributes that may have been set by inflateInit2.
! 589:
! 590: inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
! 591: stream state was inconsistent (such as zalloc or state being NULL).
! 592: */
! 593:
! 594:
! 595: /* utility functions */
! 596:
! 597: /*
! 598: The following utility functions are implemented on top of the
! 599: basic stream-oriented functions. To simplify the interface, some
! 600: default options are assumed (compression level and memory usage,
! 601: standard memory allocation functions). The source code of these
! 602: utility functions can easily be modified if you need special options.
! 603: */
! 604:
! 605: extern int ZEXPORT compress OF((Bytef *dest, uLongf *destLen,
! 606: const Bytef *source, uLong sourceLen));
! 607: /*
! 608: Compresses the source buffer into the destination buffer. sourceLen is
! 609: the byte length of the source buffer. Upon entry, destLen is the total
! 610: size of the destination buffer, which must be at least 0.1% larger than
! 611: sourceLen plus 12 bytes. Upon exit, destLen is the actual size of the
! 612: compressed buffer.
! 613: This function can be used to compress a whole file at once if the
! 614: input file is mmap'ed.
! 615: compress returns Z_OK if success, Z_MEM_ERROR if there was not
! 616: enough memory, Z_BUF_ERROR if there was not enough room in the output
! 617: buffer.
! 618: */
! 619:
! 620: extern int ZEXPORT compress2 OF((Bytef *dest, uLongf *destLen,
! 621: const Bytef *source, uLong sourceLen,
! 622: int level));
! 623: /*
! 624: Compresses the source buffer into the destination buffer. The level
! 625: parameter has the same meaning as in deflateInit. sourceLen is the byte
! 626: length of the source buffer. Upon entry, destLen is the total size of the
! 627: destination buffer, which must be at least 0.1% larger than sourceLen plus
! 628: 12 bytes. Upon exit, destLen is the actual size of the compressed buffer.
! 629:
! 630: compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
! 631: memory, Z_BUF_ERROR if there was not enough room in the output buffer,
! 632: Z_STREAM_ERROR if the level parameter is invalid.
! 633: */
! 634:
! 635: extern int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen,
! 636: const Bytef *source, uLong sourceLen));
! 637: /*
! 638: Decompresses the source buffer into the destination buffer. sourceLen is
! 639: the byte length of the source buffer. Upon entry, destLen is the total
! 640: size of the destination buffer, which must be large enough to hold the
! 641: entire uncompressed data. (The size of the uncompressed data must have
! 642: been saved previously by the compressor and transmitted to the decompressor
! 643: by some mechanism outside the scope of this compression library.)
! 644: Upon exit, destLen is the actual size of the compressed buffer.
! 645: This function can be used to decompress a whole file at once if the
! 646: input file is mmap'ed.
! 647:
! 648: uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
! 649: enough memory, Z_BUF_ERROR if there was not enough room in the output
! 650: buffer, or Z_DATA_ERROR if the input data was corrupted.
! 651: */
! 652:
! 653:
! 654: typedef voidp gzFile;
! 655:
! 656: extern gzFile ZEXPORT gzopen OF((const char *path, const char *mode));
! 657: /*
! 658: Opens a gzip (.gz) file for reading or writing. The mode parameter
! 659: is as in fopen ("rb" or "wb") but can also include a compression level
! 660: ("wb9") or a strategy: 'f' for filtered data as in "wb6f", 'h' for
! 661: Huffman only compression as in "wb1h". (See the description
! 662: of deflateInit2 for more information about the strategy parameter.)
! 663:
! 664: gzopen can be used to read a file which is not in gzip format; in this
! 665: case gzread will directly read from the file without decompression.
! 666:
! 667: gzopen returns NULL if the file could not be opened or if there was
! 668: insufficient memory to allocate the (de)compression state; errno
! 669: can be checked to distinguish the two cases (if errno is zero, the
! 670: zlib error is Z_MEM_ERROR). */
! 671:
! 672: extern gzFile ZEXPORT gzdopen OF((int fd, const char *mode));
! 673: /*
! 674: gzdopen() associates a gzFile with the file descriptor fd. File
! 675: descriptors are obtained from calls like open, dup, creat, pipe or
! 676: fileno (in the file has been previously opened with fopen).
! 677: The mode parameter is as in gzopen.
! 678: The next call of gzclose on the returned gzFile will also close the
! 679: file descriptor fd, just like fclose(fdopen(fd), mode) closes the file
! 680: descriptor fd. If you want to keep fd open, use gzdopen(dup(fd), mode).
! 681: gzdopen returns NULL if there was insufficient memory to allocate
! 682: the (de)compression state.
! 683: */
! 684:
! 685: extern int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy));
! 686: /*
! 687: Dynamically update the compression level or strategy. See the description
! 688: of deflateInit2 for the meaning of these parameters.
! 689: gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not
! 690: opened for writing.
! 691: */
! 692:
! 693: extern int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len));
! 694: /*
! 695: Reads the given number of uncompressed bytes from the compressed file.
! 696: If the input file was not in gzip format, gzread copies the given number
! 697: of bytes into the buffer.
! 698: gzread returns the number of uncompressed bytes actually read (0 for
! 699: end of file, -1 for error). */
! 700:
! 701: extern int ZEXPORT gzwrite OF((gzFile file, const voidp buf, unsigned len));
! 702: /*
! 703: Writes the given number of uncompressed bytes into the compressed file.
! 704: gzwrite returns the number of uncompressed bytes actually written
! 705: (0 in case of error).
! 706: */
! 707:
! 708: extern int ZEXPORTVA gzprintf OF((gzFile file, const char *format, ...));
! 709: /*
! 710: Converts, formats, and writes the args to the compressed file under
! 711: control of the format string, as in fprintf. gzprintf returns the number of
! 712: uncompressed bytes actually written (0 in case of error).
! 713: */
! 714:
! 715: extern int ZEXPORT gzputs OF((gzFile file, const char *s));
! 716: /*
! 717: Writes the given null-terminated string to the compressed file, excluding
! 718: the terminating null character.
! 719: gzputs returns the number of characters written, or -1 in case of error.
! 720: */
! 721:
! 722: extern char * ZEXPORT gzgets OF((gzFile file, char *buf, int len));
! 723: /*
! 724: Reads bytes from the compressed file until len-1 characters are read, or
! 725: a newline character is read and transferred to buf, or an end-of-file
! 726: condition is encountered. The string is then terminated with a null
! 727: character.
! 728: gzgets returns buf, or Z_NULL in case of error.
! 729: */
! 730:
! 731: extern int ZEXPORT gzputc OF((gzFile file, int c));
! 732: /*
! 733: Writes c, converted to an unsigned char, into the compressed file.
! 734: gzputc returns the value that was written, or -1 in case of error.
! 735: */
! 736:
! 737: extern int ZEXPORT gzgetc OF((gzFile file));
! 738: /*
! 739: Reads one byte from the compressed file. gzgetc returns this byte
! 740: or -1 in case of end of file or error.
! 741: */
! 742:
! 743: extern int ZEXPORT gzflush OF((gzFile file, int flush));
! 744: /*
! 745: Flushes all pending output into the compressed file. The parameter
! 746: flush is as in the deflate() function. The return value is the zlib
! 747: error number (see function gzerror below). gzflush returns Z_OK if
! 748: the flush parameter is Z_FINISH and all output could be flushed.
! 749: gzflush should be called only when strictly necessary because it can
! 750: degrade compression.
! 751: */
! 752:
! 753: extern z_off_t ZEXPORT gzseek OF((gzFile file, z_off_t offset, int whence));
! 754: /*
! 755: Sets the starting position for the next gzread or gzwrite on the given
! 756: compressed file. The offset represents a number of bytes in the
! 757: uncompressed data stream. The whence parameter is defined as in lseek(2);
! 758: the value SEEK_END is not supported.
! 759: If the file is opened for reading, this function is emulated but can be
! 760: extremely slow. If the file is opened for writing, only forward seeks are
! 761: supported; gzseek then compresses a sequence of zeroes up to the new
! 762: starting position.
! 763:
! 764: gzseek returns the resulting offset location as measured in bytes from
! 765: the beginning of the uncompressed stream, or -1 in case of error, in
! 766: particular if the file is opened for writing and the new starting position
! 767: would be before the current position.
! 768: */
! 769:
! 770: extern int ZEXPORT gzrewind OF((gzFile file));
! 771: /*
! 772: Rewinds the given file. This function is supported only for reading.
! 773:
! 774: gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET)
! 775: */
! 776:
! 777: extern z_off_t ZEXPORT gztell OF((gzFile file));
! 778: /*
! 779: Returns the starting position for the next gzread or gzwrite on the
! 780: given compressed file. This position represents a number of bytes in the
! 781: uncompressed data stream.
! 782:
! 783: gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)
! 784: */
! 785:
! 786: extern int ZEXPORT gzeof OF((gzFile file));
! 787: /*
! 788: Returns 1 when EOF has previously been detected reading the given
! 789: input stream, otherwise zero.
! 790: */
! 791:
! 792: extern int ZEXPORT gzclose OF((gzFile file));
! 793: /*
! 794: Flushes all pending output if necessary, closes the compressed file
! 795: and deallocates all the (de)compression state. The return value is the zlib
! 796: error number (see function gzerror below).
! 797: */
! 798:
! 799: extern const char * ZEXPORT gzerror OF((gzFile file, int *errnum));
! 800: /*
! 801: Returns the error message for the last error which occurred on the
! 802: given compressed file. errnum is set to zlib error number. If an
! 803: error occurred in the file system and not in the compression library,
! 804: errnum is set to Z_ERRNO and the application may consult errno
! 805: to get the exact error code.
! 806: */
! 807:
! 808: /* checksum functions */
! 809:
! 810: /*
! 811: These functions are not related to compression but are exported
! 812: anyway because they might be useful in applications using the
! 813: compression library.
! 814: */
! 815:
! 816: extern uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len));
! 817:
! 818: /*
! 819: Update a running Adler-32 checksum with the bytes buf[0..len-1] and
! 820: return the updated checksum. If buf is NULL, this function returns
! 821: the required initial value for the checksum.
! 822: An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
! 823: much faster. Usage example:
! 824:
! 825: uLong adler = adler32(0L, Z_NULL, 0);
! 826:
! 827: while (read_buffer(buffer, length) != EOF) {
! 828: adler = adler32(adler, buffer, length);
! 829: }
! 830: if (adler != original_adler) error();
! 831: */
! 832:
! 833: extern uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len));
! 834: /*
! 835: Update a running crc with the bytes buf[0..len-1] and return the updated
! 836: crc. If buf is NULL, this function returns the required initial value
! 837: for the crc. Pre- and post-conditioning (one's complement) is performed
! 838: within this function so it shouldn't be done by the application.
! 839: Usage example:
! 840:
! 841: uLong crc = crc32(0L, Z_NULL, 0);
! 842:
! 843: while (read_buffer(buffer, length) != EOF) {
! 844: crc = crc32(crc, buffer, length);
! 845: }
! 846: if (crc != original_crc) error();
! 847: */
! 848:
! 849:
! 850: /* various hacks, don't look :) */
! 851:
! 852: /* deflateInit and inflateInit are macros to allow checking the zlib version
! 853: * and the compiler's view of z_stream:
! 854: */
! 855: extern int ZEXPORT deflateInit_ OF((z_streamp strm, int level,
! 856: const char *version, int stream_size));
! 857: extern int ZEXPORT inflateInit_ OF((z_streamp strm,
! 858: const char *version, int stream_size));
! 859: extern int ZEXPORT deflateInit2_ OF((z_streamp strm, int level, int method,
! 860: int windowBits, int memLevel,
! 861: int strategy, const char *version,
! 862: int stream_size));
! 863: extern int ZEXPORT inflateInit2_ OF((z_streamp strm, int windowBits,
! 864: const char *version, int stream_size));
! 865: #define deflateInit(strm, level) \
! 866: deflateInit_((strm), (level), ZLIB_VERSION, sizeof(z_stream))
! 867: #define inflateInit(strm) \
! 868: inflateInit_((strm), ZLIB_VERSION, sizeof(z_stream))
! 869: #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
! 870: deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
! 871: (strategy), ZLIB_VERSION, sizeof(z_stream))
! 872: #define inflateInit2(strm, windowBits) \
! 873: inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream))
! 874:
! 875:
! 876: #if !defined(_Z_UTIL_H) && !defined(NO_DUMMY_DECL)
! 877: struct internal_state {int dummy;}; /* hack for buggy compilers */
! 878: #endif
! 879:
! 880: extern const char * ZEXPORT zError OF((int err));
! 881: extern int ZEXPORT inflateSyncPoint OF((z_streamp z));
! 882: extern const uLongf * ZEXPORT get_crc_table OF((void));
! 883:
! 884: #ifdef __cplusplus
! 885: }
! 886: #endif
! 887:
! 888: #endif /* _ZLIB_H */
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