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00001 /* zlib.h -- interface of the 'zlib' general purpose compression library
00002   version 1.2.3, July 18th, 2005
00003 
00004   Copyright (C) 1995-2005 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 http://www.ietf.org/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 "1.2.3"
00041 #define ZLIB_VERNUM 0x1230
00042 
00043 /*
00044      The 'zlib' compression library provides in-memory compression and
00045   decompression functions, including integrity checks of the uncompressed
00046   data.  This version of the library supports only one compression method
00047   (deflation) but other algorithms will be added later and will have the same
00048   stream interface.
00049 
00050      Compression can be done in a single step if the buffers are large
00051   enough (for example if an input file is mmap'ed), or can be done by
00052   repeated calls of the compression function.  In the latter case, the
00053   application must provide more input and/or consume the output
00054   (providing more output space) before each call.
00055 
00056      The compressed data format used by default by the in-memory functions is
00057   the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped
00058   around a deflate stream, which is itself documented in RFC 1951.
00059 
00060      The library also supports reading and writing files in gzip (.gz) format
00061   with an interface similar to that of stdio using the functions that start
00062   with "gz".  The gzip format is different from the zlib format.  gzip is a
00063   gzip wrapper, documented in RFC 1952, wrapped around a deflate stream.
00064 
00065      This library can optionally read and write gzip streams in memory as well.
00066 
00067      The zlib format was designed to be compact and fast for use in memory
00068   and on communications channels.  The gzip format was designed for single-
00069   file compression on file systems, has a larger header than zlib to maintain
00070   directory information, and uses a different, slower check method than zlib.
00071 
00072      The library does not install any signal handler. The decoder checks
00073   the consistency of the compressed data, so the library should never
00074   crash even in case of corrupted input.
00075 */
00076 
00077 typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size));
00078 typedef void   (*free_func)  OF((voidpf opaque, voidpf address));
00079 
00080 struct internal_state;
00081 
00082 typedef struct z_stream_s {
00083     Bytef    *next_in;  /* next input byte */
00084     uInt     avail_in;  /* number of bytes available at next_in */
00085     uLong    total_in;  /* total nb of input bytes read so far */
00086 
00087     Bytef    *next_out; /* next output byte should be put there */
00088     uInt     avail_out; /* remaining free space at next_out */
00089     uLong    total_out; /* total nb of bytes output so far */
00090 
00091     char     *msg;      /* last error message, NULL if no error */
00092     struct internal_state FAR *state; /* not visible by applications */
00093 
00094     alloc_func zalloc;  /* used to allocate the internal state */
00095     free_func  zfree;   /* used to free the internal state */
00096     voidpf     opaque;  /* private data object passed to zalloc and zfree */
00097 
00098     int     data_type;  /* best guess about the data type: binary or text */
00099     uLong   adler;      /* adler32 value of the uncompressed data */
00100     uLong   reserved;   /* reserved for future use */
00101 } z_stream;
00102 
00103 typedef z_stream FAR *z_streamp;
00104 
00105 /*
00106      gzip header information passed to and from zlib routines.  See RFC 1952
00107   for more details on the meanings of these fields.
00108 */
00109 typedef struct gz_header_s {
00110     int     text;       /* true if compressed data believed to be text */
00111     uLong   time;       /* modification time */
00112     int     xflags;     /* extra flags (not used when writing a gzip file) */
00113     int     os;         /* operating system */
00114     Bytef   *extra;     /* pointer to extra field or Z_NULL if none */
00115     uInt    extra_len;  /* extra field length (valid if extra != Z_NULL) */
00116     uInt    extra_max;  /* space at extra (only when reading header) */
00117     Bytef   *name;      /* pointer to zero-terminated file name or Z_NULL */
00118     uInt    name_max;   /* space at name (only when reading header) */
00119     Bytef   *comment;   /* pointer to zero-terminated comment or Z_NULL */
00120     uInt    comm_max;   /* space at comment (only when reading header) */
00121     int     hcrc;       /* true if there was or will be a header crc */
00122     int     done;       /* true when done reading gzip header (not used
00123                            when writing a gzip file) */
00124 } gz_header;
00125 
00126 typedef gz_header FAR *gz_headerp;
00127 
00128 /*
00129    The application must update next_in and avail_in when avail_in has
00130    dropped to zero. It must update next_out and avail_out when avail_out
00131    has dropped to zero. The application must initialize zalloc, zfree and
00132    opaque before calling the init function. All other fields are set by the
00133    compression library and must not be updated by the application.
00134 
00135    The opaque value provided by the application will be passed as the first
00136    parameter for calls of zalloc and zfree. This can be useful for custom
00137    memory management. The compression library attaches no meaning to the
00138    opaque value.
00139 
00140    zalloc must return Z_NULL if there is not enough memory for the object.
00141    If zlib is used in a multi-threaded application, zalloc and zfree must be
00142    thread safe.
00143 
00144    On 16-bit systems, the functions zalloc and zfree must be able to allocate
00145    exactly 65536 bytes, but will not be required to allocate more than this
00146    if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS,
00147    pointers returned by zalloc for objects of exactly 65536 bytes *must*
00148    have their offset normalized to zero. The default allocation function
00149    provided by this library ensures this (see zutil.c). To reduce memory
00150    requirements and avoid any allocation of 64K objects, at the expense of
00151    compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h).
00152 
00153    The fields total_in and total_out can be used for statistics or
00154    progress reports. After compression, total_in holds the total size of
00155    the uncompressed data and may be saved for use in the decompressor
00156    (particularly if the decompressor wants to decompress everything in
00157    a single step).
00158 */
00159 
00160                         /* constants */
00161 
00162 #define Z_NO_FLUSH      0
00163 #define Z_PARTIAL_FLUSH 1 /* will be removed, use Z_SYNC_FLUSH instead */
00164 #define Z_SYNC_FLUSH    2
00165 #define Z_FULL_FLUSH    3
00166 #define Z_FINISH        4
00167 #define Z_BLOCK         5
00168 /* Allowed flush values; see deflate() and inflate() below for details */
00169 
00170 #define Z_OK            0
00171 #define Z_STREAM_END    1
00172 #define Z_NEED_DICT     2
00173 #define Z_ERRNO        (-1)
00174 #define Z_STREAM_ERROR (-2)
00175 #define Z_DATA_ERROR   (-3)
00176 #define Z_MEM_ERROR    (-4)
00177 #define Z_BUF_ERROR    (-5)
00178 #define Z_VERSION_ERROR (-6)
00179 /* Return codes for the compression/decompression functions. Negative
00180  * values are errors, positive values are used for special but normal events.
00181  */
00182 
00183 #define Z_NO_COMPRESSION         0
00184 #define Z_BEST_SPEED             1
00185 #define Z_BEST_COMPRESSION       9
00186 #define Z_DEFAULT_COMPRESSION  (-1)
00187 /* compression levels */
00188 
00189 #define Z_FILTERED            1
00190 #define Z_HUFFMAN_ONLY        2
00191 #define Z_RLE                 3
00192 #define Z_FIXED               4
00193 #define Z_DEFAULT_STRATEGY    0
00194 /* compression strategy; see deflateInit2() below for details */
00195 
00196 #define Z_BINARY   0
00197 #define Z_TEXT     1
00198 #define Z_ASCII    Z_TEXT   /* for compatibility with 1.2.2 and earlier */
00199 #define Z_UNKNOWN  2
00200 /* Possible values of the data_type field (though see inflate()) */
00201 
00202 #define Z_DEFLATED   8
00203 /* The deflate compression method (the only one supported in this version) */
00204 
00205 #define Z_NULL  0  /* for initializing zalloc, zfree, opaque */
00206 
00207 #define zlib_version zlibVersion()
00208 /* for compatibility with versions < 1.0.2 */
00209 
00210                         /* basic functions */
00211 
00212 ZEXTERN const char * ZEXPORT zlibVersion OF((void));
00213 /* The application can compare zlibVersion and ZLIB_VERSION for consistency.
00214    If the first character differs, the library code actually used is
00215    not compatible with the zlib.h header file used by the application.
00216    This check is automatically made by deflateInit and inflateInit.
00217  */
00218 
00219 /*
00220 ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level));
00221 
00222      Initializes the internal stream state for compression. The fields
00223    zalloc, zfree and opaque must be initialized before by the caller.
00224    If zalloc and zfree are set to Z_NULL, deflateInit updates them to
00225    use default allocation functions.
00226 
00227      The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
00228    1 gives best speed, 9 gives best compression, 0 gives no compression at
00229    all (the input data is simply copied a block at a time).
00230    Z_DEFAULT_COMPRESSION requests a default compromise between speed and
00231    compression (currently equivalent to level 6).
00232 
00233      deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not
00234    enough memory, Z_STREAM_ERROR if level is not a valid compression level,
00235    Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
00236    with the version assumed by the caller (ZLIB_VERSION).
00237    msg is set to null if there is no error message.  deflateInit does not
00238    perform any compression: this will be done by deflate().
00239 */
00240 
00241 
00242 ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush));
00243 /*
00244     deflate compresses as much data as possible, and stops when the input
00245   buffer becomes empty or the output buffer becomes full. It may introduce some
00246   output latency (reading input without producing any output) except when
00247   forced to flush.
00248 
00249     The detailed semantics are as follows. deflate performs one or both of the
00250   following actions:
00251 
00252   - Compress more input starting at next_in and update next_in and avail_in
00253     accordingly. If not all input can be processed (because there is not
00254     enough room in the output buffer), next_in and avail_in are updated and
00255     processing will resume at this point for the next call of deflate().
00256 
00257   - Provide more output starting at next_out and update next_out and avail_out
00258     accordingly. This action is forced if the parameter flush is non zero.
00259     Forcing flush frequently degrades the compression ratio, so this parameter
00260     should be set only when necessary (in interactive applications).
00261     Some output may be provided even if flush is not set.
00262 
00263   Before the call of deflate(), the application should ensure that at least
00264   one of the actions is possible, by providing more input and/or consuming
00265   more output, and updating avail_in or avail_out accordingly; avail_out
00266   should never be zero before the call. The application can consume the
00267   compressed output when it wants, for example when the output buffer is full
00268   (avail_out == 0), or after each call of deflate(). If deflate returns Z_OK
00269   and with zero avail_out, it must be called again after making room in the
00270   output buffer because there might be more output pending.
00271 
00272     Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to
00273   decide how much data to accumualte before producing output, in order to
00274   maximize compression.
00275 
00276     If the parameter flush is set to Z_SYNC_FLUSH, all pending output is
00277   flushed to the output buffer and the output is aligned on a byte boundary, so
00278   that the decompressor can get all input data available so far. (In particular
00279   avail_in is zero after the call if enough output space has been provided
00280   before the call.)  Flushing may degrade compression for some compression
00281   algorithms and so it should be used only when necessary.
00282 
00283     If flush is set to Z_FULL_FLUSH, all output is flushed as with
00284   Z_SYNC_FLUSH, and the compression state is reset so that decompression can
00285   restart from this point if previous compressed data has been damaged or if
00286   random access is desired. Using Z_FULL_FLUSH too often can seriously degrade
00287   compression.
00288 
00289     If deflate returns with avail_out == 0, this function must be called again
00290   with the same value of the flush parameter and more output space (updated
00291   avail_out), until the flush is complete (deflate returns with non-zero
00292   avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that
00293   avail_out is greater than six to avoid repeated flush markers due to
00294   avail_out == 0 on return.
00295 
00296     If the parameter flush is set to Z_FINISH, pending input is processed,
00297   pending output is flushed and deflate returns with Z_STREAM_END if there
00298   was enough output space; if deflate returns with Z_OK, this function must be
00299   called again with Z_FINISH and more output space (updated avail_out) but no
00300   more input data, until it returns with Z_STREAM_END or an error. After
00301   deflate has returned Z_STREAM_END, the only possible operations on the
00302   stream are deflateReset or deflateEnd.
00303 
00304     Z_FINISH can be used immediately after deflateInit if all the compression
00305   is to be done in a single step. In this case, avail_out must be at least
00306   the value returned by deflateBound (see below). If deflate does not return
00307   Z_STREAM_END, then it must be called again as described above.
00308 
00309     deflate() sets strm->adler to the adler32 checksum of all input read
00310   so far (that is, total_in bytes).
00311 
00312     deflate() may update strm->data_type if it can make a good guess about
00313   the input data type (Z_BINARY or Z_TEXT). In doubt, the data is considered
00314   binary. This field is only for information purposes and does not affect
00315   the compression algorithm in any manner.
00316 
00317     deflate() returns Z_OK if some progress has been made (more input
00318   processed or more output produced), Z_STREAM_END if all input has been
00319   consumed and all output has been produced (only when flush is set to
00320   Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
00321   if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible
00322   (for example avail_in or avail_out was zero). Note that Z_BUF_ERROR is not
00323   fatal, and deflate() can be called again with more input and more output
00324   space to continue compressing.
00325 */
00326 
00327 
00328 ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm));
00329 /*
00330      All dynamically allocated data structures for this stream are freed.
00331    This function discards any unprocessed input and does not flush any
00332    pending output.
00333 
00334      deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
00335    stream state was inconsistent, Z_DATA_ERROR if the stream was freed
00336    prematurely (some input or output was discarded). In the error case,
00337    msg may be set but then points to a static string (which must not be
00338    deallocated).
00339 */
00340 
00341 
00342 /*
00343 ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm));
00344 
00345      Initializes the internal stream state for decompression. The fields
00346    next_in, avail_in, zalloc, zfree and opaque must be initialized before by
00347    the caller. If next_in is not Z_NULL and avail_in is large enough (the exact
00348    value depends on the compression method), inflateInit determines the
00349    compression method from the zlib header and allocates all data structures
00350    accordingly; otherwise the allocation will be deferred to the first call of
00351    inflate.  If zalloc and zfree are set to Z_NULL, inflateInit updates them to
00352    use default allocation functions.
00353 
00354      inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
00355    memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
00356    version assumed by the caller.  msg is set to null if there is no error
00357    message. inflateInit does not perform any decompression apart from reading
00358    the zlib header if present: this will be done by inflate().  (So next_in and
00359    avail_in may be modified, but next_out and avail_out are unchanged.)
00360 */
00361 
00362 
00363 ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush));
00364 /*
00365     inflate decompresses as much data as possible, and stops when the input
00366   buffer becomes empty or the output buffer becomes full. It may introduce
00367   some output latency (reading input without producing any output) except when
00368   forced to flush.
00369 
00370   The detailed semantics are as follows. inflate performs one or both of the
00371   following actions:
00372 
00373   - Decompress more input starting at next_in and update next_in and avail_in
00374     accordingly. If not all input can be processed (because there is not
00375     enough room in the output buffer), next_in is updated and processing
00376     will resume at this point for the next call of inflate().
00377 
00378   - Provide more output starting at next_out and update next_out and avail_out
00379     accordingly.  inflate() provides as much output as possible, until there
00380     is no more input data or no more space in the output buffer (see below
00381     about the flush parameter).
00382 
00383   Before the call of inflate(), the application should ensure that at least
00384   one of the actions is possible, by providing more input and/or consuming
00385   more output, and updating the next_* and avail_* values accordingly.
00386   The application can consume the uncompressed output when it wants, for
00387   example when the output buffer is full (avail_out == 0), or after each
00388   call of inflate(). If inflate returns Z_OK and with zero avail_out, it
00389   must be called again after making room in the output buffer because there
00390   might be more output pending.
00391 
00392     The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH,
00393   Z_FINISH, or Z_BLOCK. Z_SYNC_FLUSH requests that inflate() flush as much
00394   output as possible to the output buffer. Z_BLOCK requests that inflate() stop
00395   if and when it gets to the next deflate block boundary. When decoding the
00396   zlib or gzip format, this will cause inflate() to return immediately after
00397   the header and before the first block. When doing a raw inflate, inflate()
00398   will go ahead and process the first block, and will return when it gets to
00399   the end of that block, or when it runs out of data.
00400 
00401     The Z_BLOCK option assists in appending to or combining deflate streams.
00402   Also to assist in this, on return inflate() will set strm->data_type to the
00403   number of unused bits in the last byte taken from strm->next_in, plus 64
00404   if inflate() is currently decoding the last block in the deflate stream,
00405   plus 128 if inflate() returned immediately after decoding an end-of-block
00406   code or decoding the complete header up to just before the first byte of the
00407   deflate stream. The end-of-block will not be indicated until all of the
00408   uncompressed data from that block has been written to strm->next_out.  The
00409   number of unused bits may in general be greater than seven, except when
00410   bit 7 of data_type is set, in which case the number of unused bits will be
00411   less than eight.
00412 
00413     inflate() should normally be called until it returns Z_STREAM_END or an
00414   error. However if all decompression is to be performed in a single step
00415   (a single call of inflate), the parameter flush should be set to
00416   Z_FINISH. In this case all pending input is processed and all pending
00417   output is flushed; avail_out must be large enough to hold all the
00418   uncompressed data. (The size of the uncompressed data may have been saved
00419   by the compressor for this purpose.) The next operation on this stream must
00420   be inflateEnd to deallocate the decompression state. The use of Z_FINISH
00421   is never required, but can be used to inform inflate that a faster approach
00422   may be used for the single inflate() call.
00423 
00424      In this implementation, inflate() always flushes as much output as
00425   possible to the output buffer, and always uses the faster approach on the
00426   first call. So the only effect of the flush parameter in this implementation
00427   is on the return value of inflate(), as noted below, or when it returns early
00428   because Z_BLOCK is used.
00429 
00430      If a preset dictionary is needed after this call (see inflateSetDictionary
00431   below), inflate sets strm->adler to the adler32 checksum of the dictionary
00432   chosen by the compressor and returns Z_NEED_DICT; otherwise it sets
00433   strm->adler to the adler32 checksum of all output produced so far (that is,
00434   total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described
00435   below. At the end of the stream, inflate() checks that its computed adler32
00436   checksum is equal to that saved by the compressor and returns Z_STREAM_END
00437   only if the checksum is correct.
00438 
00439     inflate() will decompress and check either zlib-wrapped or gzip-wrapped
00440   deflate data.  The header type is detected automatically.  Any information
00441   contained in the gzip header is not retained, so applications that need that
00442   information should instead use raw inflate, see inflateInit2() below, or
00443   inflateBack() and perform their own processing of the gzip header and
00444   trailer.
00445 
00446     inflate() returns Z_OK if some progress has been made (more input processed
00447   or more output produced), Z_STREAM_END if the end of the compressed data has
00448   been reached and all uncompressed output has been produced, Z_NEED_DICT if a
00449   preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
00450   corrupted (input stream not conforming to the zlib format or incorrect check
00451   value), Z_STREAM_ERROR if the stream structure was inconsistent (for example
00452   if next_in or next_out was NULL), Z_MEM_ERROR if there was not enough memory,
00453   Z_BUF_ERROR if no progress is possible or if there was not enough room in the
00454   output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and
00455   inflate() can be called again with more input and more output space to
00456   continue decompressing. If Z_DATA_ERROR is returned, the application may then
00457   call inflateSync() to look for a good compression block if a partial recovery
00458   of the data is desired.
00459 */
00460 
00461 
00462 ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm));
00463 /*
00464      All dynamically allocated data structures for this stream are freed.
00465    This function discards any unprocessed input and does not flush any
00466    pending output.
00467 
00468      inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state
00469    was inconsistent. In the error case, msg may be set but then points to a
00470    static string (which must not be deallocated).
00471 */
00472 
00473                         /* Advanced functions */
00474 
00475 /*
00476     The following functions are needed only in some special applications.
00477 */
00478 
00479 /*
00480 ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm,
00481                                      int  level,
00482                                      int  method,
00483                                      int  windowBits,
00484                                      int  memLevel,
00485                                      int  strategy));
00486 
00487      This is another version of deflateInit with more compression options. The
00488    fields next_in, zalloc, zfree and opaque must be initialized before by
00489    the caller.
00490 
00491      The method parameter is the compression method. It must be Z_DEFLATED in
00492    this version of the library.
00493 
00494      The windowBits parameter is the base two logarithm of the window size
00495    (the size of the history buffer). It should be in the range 8..15 for this
00496    version of the library. Larger values of this parameter result in better
00497    compression at the expense of memory usage. The default value is 15 if
00498    deflateInit is used instead.
00499 
00500      windowBits can also be -8..-15 for raw deflate. In this case, -windowBits
00501    determines the window size. deflate() will then generate raw deflate data
00502    with no zlib header or trailer, and will not compute an adler32 check value.
00503 
00504      windowBits can also be greater than 15 for optional gzip encoding. Add
00505    16 to windowBits to write a simple gzip header and trailer around the
00506    compressed data instead of a zlib wrapper. The gzip header will have no
00507    file name, no extra data, no comment, no modification time (set to zero),
00508    no header crc, and the operating system will be set to 255 (unknown).  If a
00509    gzip stream is being written, strm->adler is a crc32 instead of an adler32.
00510 
00511      The memLevel parameter specifies how much memory should be allocated
00512    for the internal compression state. memLevel=1 uses minimum memory but
00513    is slow and reduces compression ratio; memLevel=9 uses maximum memory
00514    for optimal speed. The default value is 8. See zconf.h for total memory
00515    usage as a function of windowBits and memLevel.
00516 
00517      The strategy parameter is used to tune the compression algorithm. Use the
00518    value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
00519    filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no
00520    string match), or Z_RLE to limit match distances to one (run-length
00521    encoding). Filtered data consists mostly of small values with a somewhat
00522    random distribution. In this case, the compression algorithm is tuned to
00523    compress them better. The effect of Z_FILTERED is to force more Huffman
00524    coding and less string matching; it is somewhat intermediate between
00525    Z_DEFAULT and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as fast as
00526    Z_HUFFMAN_ONLY, but give better compression for PNG image data. The strategy
00527    parameter only affects the compression ratio but not the correctness of the
00528    compressed output even if it is not set appropriately.  Z_FIXED prevents the
00529    use of dynamic Huffman codes, allowing for a simpler decoder for special
00530    applications.
00531 
00532       deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
00533    memory, Z_STREAM_ERROR if a parameter is invalid (such as an invalid
00534    method). msg is set to null if there is no error message.  deflateInit2 does
00535    not perform any compression: this will be done by deflate().
00536 */
00537 
00538 ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm,
00539                                              const Bytef *dictionary,
00540                                              uInt  dictLength));
00541 /*
00542      Initializes the compression dictionary from the given byte sequence
00543    without producing any compressed output. This function must be called
00544    immediately after deflateInit, deflateInit2 or deflateReset, before any
00545    call of deflate. The compressor and decompressor must use exactly the same
00546    dictionary (see inflateSetDictionary).
00547 
00548      The dictionary should consist of strings (byte sequences) that are likely
00549    to be encountered later in the data to be compressed, with the most commonly
00550    used strings preferably put towards the end of the dictionary. Using a
00551    dictionary is most useful when the data to be compressed is short and can be
00552    predicted with good accuracy; the data can then be compressed better than
00553    with the default empty dictionary.
00554 
00555      Depending on the size of the compression data structures selected by
00556    deflateInit or deflateInit2, a part of the dictionary may in effect be
00557    discarded, for example if the dictionary is larger than the window size in
00558    deflate or deflate2. Thus the strings most likely to be useful should be
00559    put at the end of the dictionary, not at the front. In addition, the
00560    current implementation of deflate will use at most the window size minus
00561    262 bytes of the provided dictionary.
00562 
00563      Upon return of this function, strm->adler is set to the adler32 value
00564    of the dictionary; the decompressor may later use this value to determine
00565    which dictionary has been used by the compressor. (The adler32 value
00566    applies to the whole dictionary even if only a subset of the dictionary is
00567    actually used by the compressor.) If a raw deflate was requested, then the
00568    adler32 value is not computed and strm->adler is not set.
00569 
00570      deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
00571    parameter is invalid (such as NULL dictionary) or the stream state is
00572    inconsistent (for example if deflate has already been called for this stream
00573    or if the compression method is bsort). deflateSetDictionary does not
00574    perform any compression: this will be done by deflate().
00575 */
00576 
00577 ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest,
00578                                     z_streamp source));
00579 /*
00580      Sets the destination stream as a complete copy of the source stream.
00581 
00582      This function can be useful when several compression strategies will be
00583    tried, for example when there are several ways of pre-processing the input
00584    data with a filter. The streams that will be discarded should then be freed
00585    by calling deflateEnd.  Note that deflateCopy duplicates the internal
00586    compression state which can be quite large, so this strategy is slow and
00587    can consume lots of memory.
00588 
00589      deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
00590    enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
00591    (such as zalloc being NULL). msg is left unchanged in both source and
00592    destination.
00593 */
00594 
00595 ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm));
00596 /*
00597      This function is equivalent to deflateEnd followed by deflateInit,
00598    but does not free and reallocate all the internal compression state.
00599    The stream will keep the same compression level and any other attributes
00600    that may have been set by deflateInit2.
00601 
00602       deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
00603    stream state was inconsistent (such as zalloc or state being NULL).
00604 */
00605 
00606 ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm,
00607                                       int level,
00608                                       int strategy));
00609 /*
00610      Dynamically update the compression level and compression strategy.  The
00611    interpretation of level and strategy is as in deflateInit2.  This can be
00612    used to switch between compression and straight copy of the input data, or
00613    to switch to a different kind of input data requiring a different
00614    strategy. If the compression level is changed, the input available so far
00615    is compressed with the old level (and may be flushed); the new level will
00616    take effect only at the next call of deflate().
00617 
00618      Before the call of deflateParams, the stream state must be set as for
00619    a call of deflate(), since the currently available input may have to
00620    be compressed and flushed. In particular, strm->avail_out must be non-zero.
00621 
00622      deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source
00623    stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR
00624    if strm->avail_out was zero.
00625 */
00626 
00627 ZEXTERN int ZEXPORT deflateTune OF((z_streamp strm,
00628                                     int good_length,
00629                                     int max_lazy,
00630                                     int nice_length,
00631                                     int max_chain));
00632 /*
00633      Fine tune deflate's internal compression parameters.  This should only be
00634    used by someone who understands the algorithm used by zlib's deflate for
00635    searching for the best matching string, and even then only by the most
00636    fanatic optimizer trying to squeeze out the last compressed bit for their
00637    specific input data.  Read the deflate.c source code for the meaning of the
00638    max_lazy, good_length, nice_length, and max_chain parameters.
00639 
00640      deflateTune() can be called after deflateInit() or deflateInit2(), and
00641    returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream.
00642  */
00643 
00644 ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm,
00645                                        uLong sourceLen));
00646 /*
00647      deflateBound() returns an upper bound on the compressed size after
00648    deflation of sourceLen bytes.  It must be called after deflateInit()
00649    or deflateInit2().  This would be used to allocate an output buffer
00650    for deflation in a single pass, and so would be called before deflate().
00651 */
00652 
00653 ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm,
00654                                      int bits,
00655                                      int value));
00656 /*
00657      deflatePrime() inserts bits in the deflate output stream.  The intent
00658   is that this function is used to start off the deflate output with the
00659   bits leftover from a previous deflate stream when appending to it.  As such,
00660   this function can only be used for raw deflate, and must be used before the
00661   first deflate() call after a deflateInit2() or deflateReset().  bits must be
00662   less than or equal to 16, and that many of the least significant bits of
00663   value will be inserted in the output.
00664 
00665       deflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source
00666    stream state was inconsistent.
00667 */
00668 
00669 ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm,
00670                                          gz_headerp head));
00671 /*
00672       deflateSetHeader() provides gzip header information for when a gzip
00673    stream is requested by deflateInit2().  deflateSetHeader() may be called
00674    after deflateInit2() or deflateReset() and before the first call of
00675    deflate().  The text, time, os, extra field, name, and comment information
00676    in the provided gz_header structure are written to the gzip header (xflag is
00677    ignored -- the extra flags are set according to the compression level).  The
00678    caller must assure that, if not Z_NULL, name and comment are terminated with
00679    a zero byte, and that if extra is not Z_NULL, that extra_len bytes are
00680    available there.  If hcrc is true, a gzip header crc is included.  Note that
00681    the current versions of the command-line version of gzip (up through version
00682    1.3.x) do not support header crc's, and will report that it is a "multi-part
00683    gzip file" and give up.
00684 
00685       If deflateSetHeader is not used, the default gzip header has text false,
00686    the time set to zero, and os set to 255, with no extra, name, or comment
00687    fields.  The gzip header is returned to the default state by deflateReset().
00688 
00689       deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
00690    stream state was inconsistent.
00691 */
00692 
00693 /*
00694 ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm,
00695                                      int  windowBits));
00696 
00697      This is another version of inflateInit with an extra parameter. The
00698    fields next_in, avail_in, zalloc, zfree and opaque must be initialized
00699    before by the caller.
00700 
00701      The windowBits parameter is the base two logarithm of the maximum window
00702    size (the size of the history buffer).  It should be in the range 8..15 for
00703    this version of the library. The default value is 15 if inflateInit is used
00704    instead. windowBits must be greater than or equal to the windowBits value
00705    provided to deflateInit2() while compressing, or it must be equal to 15 if
00706    deflateInit2() was not used. If a compressed stream with a larger window
00707    size is given as input, inflate() will return with the error code
00708    Z_DATA_ERROR instead of trying to allocate a larger window.
00709 
00710      windowBits can also be -8..-15 for raw inflate. In this case, -windowBits
00711    determines the window size. inflate() will then process raw deflate data,
00712    not looking for a zlib or gzip header, not generating a check value, and not
00713    looking for any check values for comparison at the end of the stream. This
00714    is for use with other formats that use the deflate compressed data format
00715    such as zip.  Those formats provide their own check values. If a custom
00716    format is developed using the raw deflate format for compressed data, it is
00717    recommended that a check value such as an adler32 or a crc32 be applied to
00718    the uncompressed data as is done in the zlib, gzip, and zip formats.  For
00719    most applications, the zlib format should be used as is. Note that comments
00720    above on the use in deflateInit2() applies to the magnitude of windowBits.
00721 
00722      windowBits can also be greater than 15 for optional gzip decoding. Add
00723    32 to windowBits to enable zlib and gzip decoding with automatic header
00724    detection, or add 16 to decode only the gzip format (the zlib format will
00725    return a Z_DATA_ERROR).  If a gzip stream is being decoded, strm->adler is
00726    a crc32 instead of an adler32.
00727 
00728      inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
00729    memory, Z_STREAM_ERROR if a parameter is invalid (such as a null strm). msg
00730    is set to null if there is no error message.  inflateInit2 does not perform
00731    any decompression apart from reading the zlib header if present: this will
00732    be done by inflate(). (So next_in and avail_in may be modified, but next_out
00733    and avail_out are unchanged.)
00734 */
00735 
00736 ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm,
00737                                              const Bytef *dictionary,
00738                                              uInt  dictLength));
00739 /*
00740      Initializes the decompression dictionary from the given uncompressed byte
00741    sequence. This function must be called immediately after a call of inflate,
00742    if that call returned Z_NEED_DICT. The dictionary chosen by the compressor
00743    can be determined from the adler32 value returned by that call of inflate.
00744    The compressor and decompressor must use exactly the same dictionary (see
00745    deflateSetDictionary).  For raw inflate, this function can be called
00746    immediately after inflateInit2() or inflateReset() and before any call of
00747    inflate() to set the dictionary.  The application must insure that the
00748    dictionary that was used for compression is provided.
00749 
00750      inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
00751    parameter is invalid (such as NULL dictionary) or the stream state is
00752    inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
00753    expected one (incorrect adler32 value). inflateSetDictionary does not
00754    perform any decompression: this will be done by subsequent calls of
00755    inflate().
00756 */
00757 
00758 ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm));
00759 /*
00760     Skips invalid compressed data until a full flush point (see above the
00761   description of deflate with Z_FULL_FLUSH) can be found, or until all
00762   available input is skipped. No output is provided.
00763 
00764     inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR
00765   if no more input was provided, Z_DATA_ERROR if no flush point has been found,
00766   or Z_STREAM_ERROR if the stream structure was inconsistent. In the success
00767   case, the application may save the current current value of total_in which
00768   indicates where valid compressed data was found. In the error case, the
00769   application may repeatedly call inflateSync, providing more input each time,
00770   until success or end of the input data.
00771 */
00772 
00773 ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest,
00774                                     z_streamp source));
00775 /*
00776      Sets the destination stream as a complete copy of the source stream.
00777 
00778      This function can be useful when randomly accessing a large stream.  The
00779    first pass through the stream can periodically record the inflate state,
00780    allowing restarting inflate at those points when randomly accessing the
00781    stream.
00782 
00783      inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
00784    enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
00785    (such as zalloc being NULL). msg is left unchanged in both source and
00786    destination.
00787 */
00788 
00789 ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm));
00790 /*
00791      This function is equivalent to inflateEnd followed by inflateInit,
00792    but does not free and reallocate all the internal decompression state.
00793    The stream will keep attributes that may have been set by inflateInit2.
00794 
00795       inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
00796    stream state was inconsistent (such as zalloc or state being NULL).
00797 */
00798 
00799 ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm,
00800                                      int bits,
00801                                      int value));
00802 /*
00803      This function inserts bits in the inflate input stream.  The intent is
00804   that this function is used to start inflating at a bit position in the
00805   middle of a byte.  The provided bits will be used before any bytes are used
00806   from next_in.  This function should only be used with raw inflate, and
00807   should be used before the first inflate() call after inflateInit2() or
00808   inflateReset().  bits must be less than or equal to 16, and that many of the
00809   least significant bits of value will be inserted in the input.
00810 
00811       inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source
00812    stream state was inconsistent.
00813 */
00814 
00815 ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm,
00816                                          gz_headerp head));
00817 /*
00818       inflateGetHeader() requests that gzip header information be stored in the
00819    provided gz_header structure.  inflateGetHeader() may be called after
00820    inflateInit2() or inflateReset(), and before the first call of inflate().
00821    As inflate() processes the gzip stream, head->done is zero until the header
00822    is completed, at which time head->done is set to one.  If a zlib stream is
00823    being decoded, then head->done is set to -1 to indicate that there will be
00824    no gzip header information forthcoming.  Note that Z_BLOCK can be used to
00825    force inflate() to return immediately after header processing is complete
00826    and before any actual data is decompressed.
00827 
00828       The text, time, xflags, and os fields are filled in with the gzip header
00829    contents.  hcrc is set to true if there is a header CRC.  (The header CRC
00830    was valid if done is set to one.)  If extra is not Z_NULL, then extra_max
00831    contains the maximum number of bytes to write to extra.  Once done is true,
00832    extra_len contains the actual extra field length, and extra contains the
00833    extra field, or that field truncated if extra_max is less than extra_len.
00834    If name is not Z_NULL, then up to name_max characters are written there,
00835    terminated with a zero unless the length is greater than name_max.  If
00836    comment is not Z_NULL, then up to comm_max characters are written there,
00837    terminated with a zero unless the length is greater than comm_max.  When
00838    any of extra, name, or comment are not Z_NULL and the respective field is
00839    not present in the header, then that field is set to Z_NULL to signal its
00840    absence.  This allows the use of deflateSetHeader() with the returned
00841    structure to duplicate the header.  However if those fields are set to
00842    allocated memory, then the application will need to save those pointers
00843    elsewhere so that they can be eventually freed.
00844 
00845       If inflateGetHeader is not used, then the header information is simply
00846    discarded.  The header is always checked for validity, including the header
00847    CRC if present.  inflateReset() will reset the process to discard the header
00848    information.  The application would need to call inflateGetHeader() again to
00849    retrieve the header from the next gzip stream.
00850 
00851       inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
00852    stream state was inconsistent.
00853 */
00854 
00855 /*
00856 ZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits,
00857                                         unsigned char FAR *window));
00858 
00859      Initialize the internal stream state for decompression using inflateBack()
00860    calls.  The fields zalloc, zfree and opaque in strm must be initialized
00861    before the call.  If zalloc and zfree are Z_NULL, then the default library-
00862    derived memory allocation routines are used.  windowBits is the base two
00863    logarithm of the window size, in the range 8..15.  window is a caller
00864    supplied buffer of that size.  Except for special applications where it is
00865    assured that deflate was used with small window sizes, windowBits must be 15
00866    and a 32K byte window must be supplied to be able to decompress general
00867    deflate streams.
00868 
00869      See inflateBack() for the usage of these routines.
00870 
00871      inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of
00872    the paramaters are invalid, Z_MEM_ERROR if the internal state could not
00873    be allocated, or Z_VERSION_ERROR if the version of the library does not
00874    match the version of the header file.
00875 */
00876 
00877 typedef unsigned (*in_func) OF((void FAR *, unsigned char FAR * FAR *));
00878 typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned));
00879 
00880 ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm,
00881                                     in_func in, void FAR *in_desc,
00882                                     out_func out, void FAR *out_desc));
00883 /*
00884      inflateBack() does a raw inflate with a single call using a call-back
00885    interface for input and output.  This is more efficient than inflate() for
00886    file i/o applications in that it avoids copying between the output and the
00887    sliding window by simply making the window itself the output buffer.  This
00888    function trusts the application to not change the output buffer passed by
00889    the output function, at least until inflateBack() returns.
00890 
00891      inflateBackInit() must be called first to allocate the internal state
00892    and to initialize the state with the user-provided window buffer.
00893    inflateBack() may then be used multiple times to inflate a complete, raw
00894    deflate stream with each call.  inflateBackEnd() is then called to free
00895    the allocated state.
00896 
00897      A raw deflate stream is one with no zlib or gzip header or trailer.
00898    This routine would normally be used in a utility that reads zip or gzip
00899    files and writes out uncompressed files.  The utility would decode the
00900    header and process the trailer on its own, hence this routine expects
00901    only the raw deflate stream to decompress.  This is different from the
00902    normal behavior of inflate(), which expects either a zlib or gzip header and
00903    trailer around the deflate stream.
00904 
00905      inflateBack() uses two subroutines supplied by the caller that are then
00906    called by inflateBack() for input and output.  inflateBack() calls those
00907    routines until it reads a complete deflate stream and writes out all of the
00908    uncompressed data, or until it encounters an error.  The function's
00909    parameters and return types are defined above in the in_func and out_func
00910    typedefs.  inflateBack() will call in(in_desc, &buf) which should return the
00911    number of bytes of provided input, and a pointer to that input in buf.  If
00912    there is no input available, in() must return zero--buf is ignored in that
00913    case--and inflateBack() will return a buffer error.  inflateBack() will call
00914    out(out_desc, buf, len) to write the uncompressed data buf[0..len-1].  out()
00915    should return zero on success, or non-zero on failure.  If out() returns
00916    non-zero, inflateBack() will return with an error.  Neither in() nor out()
00917    are permitted to change the contents of the window provided to
00918    inflateBackInit(), which is also the buffer that out() uses to write from.
00919    The length written by out() will be at most the window size.  Any non-zero
00920    amount of input may be provided by in().
00921 
00922      For convenience, inflateBack() can be provided input on the first call by
00923    setting strm->next_in and strm->avail_in.  If that input is exhausted, then
00924    in() will be called.  Therefore strm->next_in must be initialized before
00925    calling inflateBack().  If strm->next_in is Z_NULL, then in() will be called
00926    immediately for input.  If strm->next_in is not Z_NULL, then strm->avail_in
00927    must also be initialized, and then if strm->avail_in is not zero, input will
00928    initially be taken from strm->next_in[0 .. strm->avail_in - 1].
00929 
00930      The in_desc and out_desc parameters of inflateBack() is passed as the
00931    first parameter of in() and out() respectively when they are called.  These
00932    descriptors can be optionally used to pass any information that the caller-
00933    supplied in() and out() functions need to do their job.
00934 
00935      On return, inflateBack() will set strm->next_in and strm->avail_in to
00936    pass back any unused input that was provided by the last in() call.  The
00937    return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR
00938    if in() or out() returned an error, Z_DATA_ERROR if there was a format
00939    error in the deflate stream (in which case strm->msg is set to indicate the
00940    nature of the error), or Z_STREAM_ERROR if the stream was not properly
00941    initialized.  In the case of Z_BUF_ERROR, an input or output error can be
00942    distinguished using strm->next_in which will be Z_NULL only if in() returned
00943    an error.  If strm->next is not Z_NULL, then the Z_BUF_ERROR was due to
00944    out() returning non-zero.  (in() will always be called before out(), so
00945    strm->next_in is assured to be defined if out() returns non-zero.)  Note
00946    that inflateBack() cannot return Z_OK.
00947 */
00948 
00949 ZEXTERN int ZEXPORT inflateBackEnd OF((z_streamp strm));
00950 /*
00951      All memory allocated by inflateBackInit() is freed.
00952 
00953      inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream
00954    state was inconsistent.
00955 */
00956 
00957 ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void));
00958 /* Return flags indicating compile-time options.
00959 
00960     Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other:
00961      1.0: size of uInt
00962      3.2: size of uLong
00963      5.4: size of voidpf (pointer)
00964      7.6: size of z_off_t
00965 
00966     Compiler, assembler, and debug options:
00967      8: DEBUG
00968      9: ASMV or ASMINF -- use ASM code
00969      10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention
00970      11: 0 (reserved)
00971 
00972     One-time table building (smaller code, but not thread-safe if true):
00973      12: BUILDFIXED -- build static block decoding tables when needed
00974      13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed
00975      14,15: 0 (reserved)
00976 
00977     Library content (indicates missing functionality):
00978      16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking
00979                           deflate code when not needed)
00980      17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect
00981                     and decode gzip streams (to avoid linking crc code)
00982      18-19: 0 (reserved)
00983 
00984     Operation variations (changes in library functionality):
00985      20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate
00986      21: FASTEST -- deflate algorithm with only one, lowest compression level
00987      22,23: 0 (reserved)
00988 
00989     The sprintf variant used by gzprintf (zero is best):
00990      24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format
00991      25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure!
00992      26: 0 = returns value, 1 = void -- 1 means inferred string length returned
00993 
00994     Remainder:
00995      27-31: 0 (reserved)
00996  */
00997 
00998 
00999                         /* utility functions */
01000 
01001 /*
01002      The following utility functions are implemented on top of the
01003    basic stream-oriented functions. To simplify the interface, some
01004    default options are assumed (compression level and memory usage,
01005    standard memory allocation functions). The source code of these
01006    utility functions can easily be modified if you need special options.
01007 */
01008 
01009 ZEXTERN int ZEXPORT compress OF((Bytef *dest,   uLongf *destLen,
01010                                  const Bytef *source, uLong sourceLen));
01011 /*
01012      Compresses the source buffer into the destination buffer.  sourceLen is
01013    the byte length of the source buffer. Upon entry, destLen is the total
01014    size of the destination buffer, which must be at least the value returned
01015    by compressBound(sourceLen). Upon exit, destLen is the actual size of the
01016    compressed buffer.
01017      This function can be used to compress a whole file at once if the
01018    input file is mmap'ed.
01019      compress returns Z_OK if success, Z_MEM_ERROR if there was not
01020    enough memory, Z_BUF_ERROR if there was not enough room in the output
01021    buffer.
01022 */
01023 
01024 ZEXTERN int ZEXPORT compress2 OF((Bytef *dest,   uLongf *destLen,
01025                                   const Bytef *source, uLong sourceLen,
01026                                   int level));
01027 /*
01028      Compresses the source buffer into the destination buffer. The level
01029    parameter has the same meaning as in deflateInit.  sourceLen is the byte
01030    length of the source buffer. Upon entry, destLen is the total size of the
01031    destination buffer, which must be at least the value returned by
01032    compressBound(sourceLen). Upon exit, destLen is the actual size of the
01033    compressed buffer.
01034 
01035      compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
01036    memory, Z_BUF_ERROR if there was not enough room in the output buffer,
01037    Z_STREAM_ERROR if the level parameter is invalid.
01038 */
01039 
01040 ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen));
01041 /*
01042      compressBound() returns an upper bound on the compressed size after
01043    compress() or compress2() on sourceLen bytes.  It would be used before
01044    a compress() or compress2() call to allocate the destination buffer.
01045 */
01046 
01047 ZEXTERN int ZEXPORT uncompress OF((Bytef *dest,   uLongf *destLen,
01048                                    const Bytef *source, uLong sourceLen));
01049 /*
01050      Decompresses the source buffer into the destination buffer.  sourceLen is
01051    the byte length of the source buffer. Upon entry, destLen is the total
01052    size of the destination buffer, which must be large enough to hold the
01053    entire uncompressed data. (The size of the uncompressed data must have
01054    been saved previously by the compressor and transmitted to the decompressor
01055    by some mechanism outside the scope of this compression library.)
01056    Upon exit, destLen is the actual size of the compressed buffer.
01057      This function can be used to decompress a whole file at once if the
01058    input file is mmap'ed.
01059 
01060      uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
01061    enough memory, Z_BUF_ERROR if there was not enough room in the output
01062    buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete.
01063 */
01064 
01065 
01066 typedef voidp gzFile;
01067 
01068 ZEXTERN gzFile ZEXPORT gzopen  OF((const char *path, const char *mode));
01069 /*
01070      Opens a gzip (.gz) file for reading or writing. The mode parameter
01071    is as in fopen ("rb" or "wb") but can also include a compression level
01072    ("wb9") or a strategy: 'f' for filtered data as in "wb6f", 'h' for
01073    Huffman only compression as in "wb1h", or 'R' for run-length encoding
01074    as in "wb1R". (See the description of deflateInit2 for more information
01075    about the strategy parameter.)
01076 
01077      gzopen can be used to read a file which is not in gzip format; in this
01078    case gzread will directly read from the file without decompression.
01079 
01080      gzopen returns NULL if the file could not be opened or if there was
01081    insufficient memory to allocate the (de)compression state; errno
01082    can be checked to distinguish the two cases (if errno is zero, the
01083    zlib error is Z_MEM_ERROR).  */
01084 
01085 ZEXTERN gzFile ZEXPORT gzdopen  OF((int fd, const char *mode));
01086 /*
01087      gzdopen() associates a gzFile with the file descriptor fd.  File
01088    descriptors are obtained from calls like open, dup, creat, pipe or
01089    fileno (in the file has been previously opened with fopen).
01090    The mode parameter is as in gzopen.
01091      The next call of gzclose on the returned gzFile will also close the
01092    file descriptor fd, just like fclose(fdopen(fd), mode) closes the file
01093    descriptor fd. If you want to keep fd open, use gzdopen(dup(fd), mode).
01094      gzdopen returns NULL if there was insufficient memory to allocate
01095    the (de)compression state.
01096 */
01097 
01098 ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy));
01099 /*
01100      Dynamically update the compression level or strategy. See the description
01101    of deflateInit2 for the meaning of these parameters.
01102      gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not
01103    opened for writing.
01104 */
01105 
01106 ZEXTERN int ZEXPORT    gzread  OF((gzFile file, voidp buf, unsigned len));
01107 /*
01108      Reads the given number of uncompressed bytes from the compressed file.
01109    If the input file was not in gzip format, gzread copies the given number
01110    of bytes into the buffer.
01111      gzread returns the number of uncompressed bytes actually read (0 for
01112    end of file, -1 for error). */
01113 
01114 ZEXTERN int ZEXPORT    gzwrite OF((gzFile file,
01115                                    voidpc buf, unsigned len));
01116 /*
01117      Writes the given number of uncompressed bytes into the compressed file.
01118    gzwrite returns the number of uncompressed bytes actually written
01119    (0 in case of error).
01120 */
01121 
01122 ZEXTERN int ZEXPORTVA   gzprintf OF((gzFile file, const char *format, ...));
01123 /*
01124      Converts, formats, and writes the args to the compressed file under
01125    control of the format string, as in fprintf. gzprintf returns the number of
01126    uncompressed bytes actually written (0 in case of error).  The number of
01127    uncompressed bytes written is limited to 4095. The caller should assure that
01128    this limit is not exceeded. If it is exceeded, then gzprintf() will return
01129    return an error (0) with nothing written. In this case, there may also be a
01130    buffer overflow with unpredictable consequences, which is possible only if
01131    zlib was compiled with the insecure functions sprintf() or vsprintf()
01132    because the secure snprintf() or vsnprintf() functions were not available.
01133 */
01134 
01135 ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s));
01136 /*
01137       Writes the given null-terminated string to the compressed file, excluding
01138    the terminating null character.
01139       gzputs returns the number of characters written, or -1 in case of error.
01140 */
01141 
01142 ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len));
01143 /*
01144       Reads bytes from the compressed file until len-1 characters are read, or
01145    a newline character is read and transferred to buf, or an end-of-file
01146    condition is encountered.  The string is then terminated with a null
01147    character.
01148       gzgets returns buf, or Z_NULL in case of error.
01149 */
01150 
01151 ZEXTERN int ZEXPORT    gzputc OF((gzFile file, int c));
01152 /*
01153       Writes c, converted to an unsigned char, into the compressed file.
01154    gzputc returns the value that was written, or -1 in case of error.
01155 */
01156 
01157 ZEXTERN int ZEXPORT    gzgetc OF((gzFile file));
01158 /*
01159       Reads one byte from the compressed file. gzgetc returns this byte
01160    or -1 in case of end of file or error.
01161 */
01162 
01163 ZEXTERN int ZEXPORT    gzungetc OF((int c, gzFile file));
01164 /*
01165       Push one character back onto the stream to be read again later.
01166    Only one character of push-back is allowed.  gzungetc() returns the
01167    character pushed, or -1 on failure.  gzungetc() will fail if a
01168    character has been pushed but not read yet, or if c is -1. The pushed
01169    character will be discarded if the stream is repositioned with gzseek()
01170    or gzrewind().
01171 */
01172 
01173 ZEXTERN int ZEXPORT    gzflush OF((gzFile file, int flush));
01174 /*
01175      Flushes all pending output into the compressed file. The parameter
01176    flush is as in the deflate() function. The return value is the zlib
01177    error number (see function gzerror below). gzflush returns Z_OK if
01178    the flush parameter is Z_FINISH and all output could be flushed.
01179      gzflush should be called only when strictly necessary because it can
01180    degrade compression.
01181 */
01182 
01183 ZEXTERN z_off_t ZEXPORT    gzseek OF((gzFile file,
01184                                       z_off_t offset, int whence));
01185 /*
01186       Sets the starting position for the next gzread or gzwrite on the
01187    given compressed file. The offset represents a number of bytes in the
01188    uncompressed data stream. The whence parameter is defined as in lseek(2);
01189    the value SEEK_END is not supported.
01190      If the file is opened for reading, this function is emulated but can be
01191    extremely slow. If the file is opened for writing, only forward seeks are
01192    supported; gzseek then compresses a sequence of zeroes up to the new
01193    starting position.
01194 
01195       gzseek returns the resulting offset location as measured in bytes from
01196    the beginning of the uncompressed stream, or -1 in case of error, in
01197    particular if the file is opened for writing and the new starting position
01198    would be before the current position.
01199 */
01200 
01201 ZEXTERN int ZEXPORT    gzrewind OF((gzFile file));
01202 /*
01203      Rewinds the given file. This function is supported only for reading.
01204 
01205    gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET)
01206 */
01207 
01208 ZEXTERN z_off_t ZEXPORT    gztell OF((gzFile file));
01209 /*
01210      Returns the starting position for the next gzread or gzwrite on the
01211    given compressed file. This position represents a number of bytes in the
01212    uncompressed data stream.
01213 
01214    gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)
01215 */
01216 
01217 ZEXTERN int ZEXPORT gzeof OF((gzFile file));
01218 /*
01219      Returns 1 when EOF has previously been detected reading the given
01220    input stream, otherwise zero.
01221 */
01222 
01223 ZEXTERN int ZEXPORT gzdirect OF((gzFile file));
01224 /*
01225      Returns 1 if file is being read directly without decompression, otherwise
01226    zero.
01227 */
01228 
01229 ZEXTERN int ZEXPORT    gzclose OF((gzFile file));
01230 /*
01231      Flushes all pending output if necessary, closes the compressed file
01232    and deallocates all the (de)compression state. The return value is the zlib
01233    error number (see function gzerror below).
01234 */
01235 
01236 ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum));
01237 /*
01238      Returns the error message for the last error which occurred on the
01239    given compressed file. errnum is set to zlib error number. If an
01240    error occurred in the file system and not in the compression library,
01241    errnum is set to Z_ERRNO and the application may consult errno
01242    to get the exact error code.
01243 */
01244 
01245 ZEXTERN void ZEXPORT gzclearerr OF((gzFile file));
01246 /*
01247      Clears the error and end-of-file flags for file. This is analogous to the
01248    clearerr() function in stdio. This is useful for continuing to read a gzip
01249    file that is being written concurrently.
01250 */
01251 
01252                         /* checksum functions */
01253 
01254 /*
01255      These functions are not related to compression but are exported
01256    anyway because they might be useful in applications using the
01257    compression library.
01258 */
01259 
01260 ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len));
01261 /*
01262      Update a running Adler-32 checksum with the bytes buf[0..len-1] and
01263    return the updated checksum. If buf is NULL, this function returns
01264    the required initial value for the checksum.
01265    An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
01266    much faster. Usage example:
01267 
01268      uLong adler = adler32(0L, Z_NULL, 0);
01269 
01270      while (read_buffer(buffer, length) != EOF) {
01271        adler = adler32(adler, buffer, length);
01272      }
01273      if (adler != original_adler) error();
01274 */
01275 
01276 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong adler1, uLong adler2,
01277                                           z_off_t len2));
01278 /*
01279      Combine two Adler-32 checksums into one.  For two sequences of bytes, seq1
01280    and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for
01281    each, adler1 and adler2.  adler32_combine() returns the Adler-32 checksum of
01282    seq1 and seq2 concatenated, requiring only adler1, adler2, and len2.
01283 */
01284 
01285 ZEXTERN uLong ZEXPORT crc32   OF((uLong crc, const Bytef *buf, uInt len));
01286 /*
01287      Update a running CRC-32 with the bytes buf[0..len-1] and return the
01288    updated CRC-32. If buf is NULL, this function returns the required initial
01289    value for the for the crc. Pre- and post-conditioning (one's complement) is
01290    performed within this function so it shouldn't be done by the application.
01291    Usage example:
01292 
01293      uLong crc = crc32(0L, Z_NULL, 0);
01294 
01295      while (read_buffer(buffer, length) != EOF) {
01296        crc = crc32(crc, buffer, length);
01297      }
01298      if (crc != original_crc) error();
01299 */
01300 
01301 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2));
01302 
01303 /*
01304      Combine two CRC-32 check values into one.  For two sequences of bytes,
01305    seq1 and seq2 with lengths len1 and len2, CRC-32 check values were
01306    calculated for each, crc1 and crc2.  crc32_combine() returns the CRC-32
01307    check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and
01308    len2.
01309 */
01310 
01311 
01312                         /* various hacks, don't look :) */
01313 
01314 /* deflateInit and inflateInit are macros to allow checking the zlib version
01315  * and the compiler's view of z_stream:
01316  */
01317 ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level,
01318                                      const char *version, int stream_size));
01319 ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm,
01320                                      const char *version, int stream_size));
01321 ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int  level, int  method,
01322                                       int windowBits, int memLevel,
01323                                       int strategy, const char *version,
01324                                       int stream_size));
01325 ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int  windowBits,
01326                                       const char *version, int stream_size));
01327 ZEXTERN int ZEXPORT inflateBackInit_ OF((z_streamp strm, int windowBits,
01328                                          unsigned char FAR *window,
01329                                          const char *version,
01330                                          int stream_size));
01331 #define deflateInit(strm, level) \
01332         deflateInit_((strm), (level),       ZLIB_VERSION, sizeof(z_stream))
01333 #define inflateInit(strm) \
01334         inflateInit_((strm),                ZLIB_VERSION, sizeof(z_stream))
01335 #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
01336         deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
01337                       (strategy),           ZLIB_VERSION, sizeof(z_stream))
01338 #define inflateInit2(strm, windowBits) \
01339         inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream))
01340 #define inflateBackInit(strm, windowBits, window) \
01341         inflateBackInit_((strm), (windowBits), (window), \
01342         ZLIB_VERSION, sizeof(z_stream))
01343 
01344 
01345 #if !defined(ZUTIL_H) && !defined(NO_DUMMY_DECL)
01346     struct internal_state {int dummy;}; /* hack for buggy compilers */
01347 #endif
01348 
01349 ZEXTERN const char   * ZEXPORT zError           OF((int));
01350 ZEXTERN int            ZEXPORT inflateSyncPoint OF((z_streamp z));
01351 ZEXTERN const uLongf * ZEXPORT get_crc_table    OF((void));
01352 
01353 #ifdef __cplusplus
01354 }
01355 #endif
01356 
01357 #endif /* ZLIB_H */