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# zlib.h

    00001 /* zlib.h -- interface of the 'zlib' general purpose compression library
    00002   version 1.1.4, March 11th, 2002
    00003
    00004   Copyright (C) 1995-2002 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 "1.1.4"
    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 */