misc/quazip/zlib.h
changeset 8057 93e16240f178
parent 8051 f26422ef0333
parent 8055 04dd8b7fb605
child 8058 bcebfc477459
equal deleted inserted replaced
8051:f26422ef0333 8057:93e16240f178
     1 /* zlib.h -- interface of the 'zlib' general purpose compression library
       
     2   version 1.2.3, July 18th, 2005
       
     3 
       
     4   Copyright (C) 1995-2005 Jean-loup Gailly and Mark Adler
       
     5 
       
     6   This software is provided 'as-is', without any express or implied
       
     7   warranty.  In no event will the authors be held liable for any damages
       
     8   arising from the use of this software.
       
     9 
       
    10   Permission is granted to anyone to use this software for any purpose,
       
    11   including commercial applications, and to alter it and redistribute it
       
    12   freely, subject to the following restrictions:
       
    13 
       
    14   1. The origin of this software must not be misrepresented; you must not
       
    15      claim that you wrote the original software. If you use this software
       
    16      in a product, an acknowledgment in the product documentation would be
       
    17      appreciated but is not required.
       
    18   2. Altered source versions must be plainly marked as such, and must not be
       
    19      misrepresented as being the original software.
       
    20   3. This notice may not be removed or altered from any source distribution.
       
    21 
       
    22   Jean-loup Gailly        Mark Adler
       
    23   jloup@gzip.org          madler@alumni.caltech.edu
       
    24 
       
    25 
       
    26   The data format used by the zlib library is described by RFCs (Request for
       
    27   Comments) 1950 to 1952 in the files http://www.ietf.org/rfc/rfc1950.txt
       
    28   (zlib format), rfc1951.txt (deflate format) and rfc1952.txt (gzip format).
       
    29 */
       
    30 
       
    31 #ifndef ZLIB_H
       
    32 #define ZLIB_H
       
    33 
       
    34 #include "zconf.h"
       
    35 #include "qconfig.h"
       
    36 
       
    37 #ifdef __cplusplus
       
    38 extern "C" {
       
    39 #endif
       
    40 
       
    41 #define ZLIB_VERSION "1.2.3"
       
    42 #define ZLIB_VERNUM 0x1230
       
    43 
       
    44 #if defined(QT_VISIBILITY_AVAILABLE)
       
    45 # define Q_ZEXPORT __attribute__((visibility("default")))
       
    46 #else
       
    47 # ifdef QT_MAKEDLL
       
    48 # define Q_ZEXPORT __declspec(dllexport)
       
    49 # else
       
    50 # define Q_ZEXPORT ZEXPORT
       
    51 # endif
       
    52 #endif
       
    53 
       
    54 /*
       
    55      The 'zlib' compression library provides in-memory compression and
       
    56   decompression functions, including integrity checks of the uncompressed
       
    57   data.  This version of the library supports only one compression method
       
    58   (deflation) but other algorithms will be added later and will have the same
       
    59   stream interface.
       
    60 
       
    61      Compression can be done in a single step if the buffers are large
       
    62   enough (for example if an input file is mmap'ed), or can be done by
       
    63   repeated calls of the compression function.  In the latter case, the
       
    64   application must provide more input and/or consume the output
       
    65   (providing more output space) before each call.
       
    66 
       
    67      The compressed data format used by default by the in-memory functions is
       
    68   the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped
       
    69   around a deflate stream, which is itself documented in RFC 1951.
       
    70 
       
    71      The library also supports reading and writing files in gzip (.gz) format
       
    72   with an interface similar to that of stdio using the functions that start
       
    73   with "gz".  The gzip format is different from the zlib format.  gzip is a
       
    74   gzip wrapper, documented in RFC 1952, wrapped around a deflate stream.
       
    75 
       
    76      This library can optionally read and write gzip streams in memory as well.
       
    77 
       
    78      The zlib format was designed to be compact and fast for use in memory
       
    79   and on communications channels.  The gzip format was designed for single-
       
    80   file compression on file systems, has a larger header than zlib to maintain
       
    81   directory information, and uses a different, slower check method than zlib.
       
    82 
       
    83      The library does not install any signal handler. The decoder checks
       
    84   the consistency of the compressed data, so the library should never
       
    85   crash even in case of corrupted input.
       
    86 */
       
    87 
       
    88 typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size));
       
    89 typedef void   (*free_func)  OF((voidpf opaque, voidpf address));
       
    90 
       
    91 struct internal_state;
       
    92 
       
    93 typedef struct z_stream_s {
       
    94     Bytef    *next_in;  /* next input byte */
       
    95     uInt     avail_in;  /* number of bytes available at next_in */
       
    96     uLong    total_in;  /* total nb of input bytes read so far */
       
    97 
       
    98     Bytef    *next_out; /* next output byte should be put there */
       
    99     uInt     avail_out; /* remaining free space at next_out */
       
   100     uLong    total_out; /* total nb of bytes output so far */
       
   101 
       
   102     char     *msg;      /* last error message, NULL if no error */
       
   103     struct internal_state FAR *state; /* not visible by applications */
       
   104 
       
   105     alloc_func zalloc;  /* used to allocate the internal state */
       
   106     free_func  zfree;   /* used to free the internal state */
       
   107     voidpf     opaque;  /* private data object passed to zalloc and zfree */
       
   108 
       
   109     int     data_type;  /* best guess about the data type: binary or text */
       
   110     uLong   adler;      /* adler32 value of the uncompressed data */
       
   111     uLong   reserved;   /* reserved for future use */
       
   112 } z_stream;
       
   113 
       
   114 typedef z_stream FAR *z_streamp;
       
   115 
       
   116 /*
       
   117      gzip header information passed to and from zlib routines.  See RFC 1952
       
   118   for more details on the meanings of these fields.
       
   119 */
       
   120 typedef struct gz_header_s {
       
   121     int     text;       /* true if compressed data believed to be text */
       
   122     uLong   time;       /* modification time */
       
   123     int     xflags;     /* extra flags (not used when writing a gzip file) */
       
   124     int     os;         /* operating system */
       
   125     Bytef   *extra;     /* pointer to extra field or Z_NULL if none */
       
   126     uInt    extra_len;  /* extra field length (valid if extra != Z_NULL) */
       
   127     uInt    extra_max;  /* space at extra (only when reading header) */
       
   128     Bytef   *name;      /* pointer to zero-terminated file name or Z_NULL */
       
   129     uInt    name_max;   /* space at name (only when reading header) */
       
   130     Bytef   *comment;   /* pointer to zero-terminated comment or Z_NULL */
       
   131     uInt    comm_max;   /* space at comment (only when reading header) */
       
   132     int     hcrc;       /* true if there was or will be a header crc */
       
   133     int     done;       /* true when done reading gzip header (not used
       
   134                            when writing a gzip file) */
       
   135 } gz_header;
       
   136 
       
   137 typedef gz_header FAR *gz_headerp;
       
   138 
       
   139 /*
       
   140    The application must update next_in and avail_in when avail_in has
       
   141    dropped to zero. It must update next_out and avail_out when avail_out
       
   142    has dropped to zero. The application must initialize zalloc, zfree and
       
   143    opaque before calling the init function. All other fields are set by the
       
   144    compression library and must not be updated by the application.
       
   145 
       
   146    The opaque value provided by the application will be passed as the first
       
   147    parameter for calls of zalloc and zfree. This can be useful for custom
       
   148    memory management. The compression library attaches no meaning to the
       
   149    opaque value.
       
   150 
       
   151    zalloc must return Z_NULL if there is not enough memory for the object.
       
   152    If zlib is used in a multi-threaded application, zalloc and zfree must be
       
   153    thread safe.
       
   154 
       
   155    On 16-bit systems, the functions zalloc and zfree must be able to allocate
       
   156    exactly 65536 bytes, but will not be required to allocate more than this
       
   157    if the symbol MAXSEG_64K is defined (see zconf.h). WARNING: On MSDOS,
       
   158    pointers returned by zalloc for objects of exactly 65536 bytes *must*
       
   159    have their offset normalized to zero. The default allocation function
       
   160    provided by this library ensures this (see zutil.c). To reduce memory
       
   161    requirements and avoid any allocation of 64K objects, at the expense of
       
   162    compression ratio, compile the library with -DMAX_WBITS=14 (see zconf.h).
       
   163 
       
   164    The fields total_in and total_out can be used for statistics or
       
   165    progress reports. After compression, total_in holds the total size of
       
   166    the uncompressed data and may be saved for use in the decompressor
       
   167    (particularly if the decompressor wants to decompress everything in
       
   168    a single step).
       
   169 */
       
   170 
       
   171                         /* constants */
       
   172 
       
   173 #define Z_NO_FLUSH      0
       
   174 #define Z_PARTIAL_FLUSH 1 /* will be removed, use Z_SYNC_FLUSH instead */
       
   175 #define Z_SYNC_FLUSH    2
       
   176 #define Z_FULL_FLUSH    3
       
   177 #define Z_FINISH        4
       
   178 #define Z_BLOCK         5
       
   179 /* Allowed flush values; see deflate() and inflate() below for details */
       
   180 
       
   181 #define Z_OK            0
       
   182 #define Z_STREAM_END    1
       
   183 #define Z_NEED_DICT     2
       
   184 #define Z_ERRNO        (-1)
       
   185 #define Z_STREAM_ERROR (-2)
       
   186 #define Z_DATA_ERROR   (-3)
       
   187 #define Z_MEM_ERROR    (-4)
       
   188 #define Z_BUF_ERROR    (-5)
       
   189 #define Z_VERSION_ERROR (-6)
       
   190 /* Return codes for the compression/decompression functions. Negative
       
   191  * values are errors, positive values are used for special but normal events.
       
   192  */
       
   193 
       
   194 #define Z_NO_COMPRESSION         0
       
   195 #define Z_BEST_SPEED             1
       
   196 #define Z_BEST_COMPRESSION       9
       
   197 #define Z_DEFAULT_COMPRESSION  (-1)
       
   198 /* compression levels */
       
   199 
       
   200 #define Z_FILTERED            1
       
   201 #define Z_HUFFMAN_ONLY        2
       
   202 #define Z_RLE                 3
       
   203 #define Z_FIXED               4
       
   204 #define Z_DEFAULT_STRATEGY    0
       
   205 /* compression strategy; see deflateInit2() below for details */
       
   206 
       
   207 #define Z_BINARY   0
       
   208 #define Z_TEXT     1
       
   209 #define Z_ASCII    Z_TEXT   /* for compatibility with 1.2.2 and earlier */
       
   210 #define Z_UNKNOWN  2
       
   211 /* Possible values of the data_type field (though see inflate()) */
       
   212 
       
   213 #define Z_DEFLATED   8
       
   214 /* The deflate compression method (the only one supported in this version) */
       
   215 
       
   216 #define Z_NULL  0  /* for initializing zalloc, zfree, opaque */
       
   217 
       
   218 #define zlib_version zlibVersion()
       
   219 /* for compatibility with versions < 1.0.2 */
       
   220 
       
   221                         /* basic functions */
       
   222 
       
   223 ZEXTERN Q_ZEXPORT const char * zlibVersion OF((void));
       
   224 /* The application can compare zlibVersion and ZLIB_VERSION for consistency.
       
   225    If the first character differs, the library code actually used is
       
   226    not compatible with the zlib.h header file used by the application.
       
   227    This check is automatically made by deflateInit and inflateInit.
       
   228  */
       
   229 
       
   230 /*
       
   231 ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level));
       
   232 
       
   233      Initializes the internal stream state for compression. The fields
       
   234    zalloc, zfree and opaque must be initialized before by the caller.
       
   235    If zalloc and zfree are set to Z_NULL, deflateInit updates them to
       
   236    use default allocation functions.
       
   237 
       
   238      The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
       
   239    1 gives best speed, 9 gives best compression, 0 gives no compression at
       
   240    all (the input data is simply copied a block at a time).
       
   241    Z_DEFAULT_COMPRESSION requests a default compromise between speed and
       
   242    compression (currently equivalent to level 6).
       
   243 
       
   244      deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not
       
   245    enough memory, Z_STREAM_ERROR if level is not a valid compression level,
       
   246    Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
       
   247    with the version assumed by the caller (ZLIB_VERSION).
       
   248    msg is set to null if there is no error message.  deflateInit does not
       
   249    perform any compression: this will be done by deflate().
       
   250 */
       
   251 
       
   252 
       
   253 ZEXTERN int Q_ZEXPORT deflate OF((z_streamp strm, int flush));
       
   254 /*
       
   255     deflate compresses as much data as possible, and stops when the input
       
   256   buffer becomes empty or the output buffer becomes full. It may introduce some
       
   257   output latency (reading input without producing any output) except when
       
   258   forced to flush.
       
   259 
       
   260     The detailed semantics are as follows. deflate performs one or both of the
       
   261   following actions:
       
   262 
       
   263   - Compress more input starting at next_in and update next_in and avail_in
       
   264     accordingly. If not all input can be processed (because there is not
       
   265     enough room in the output buffer), next_in and avail_in are updated and
       
   266     processing will resume at this point for the next call of deflate().
       
   267 
       
   268   - Provide more output starting at next_out and update next_out and avail_out
       
   269     accordingly. This action is forced if the parameter flush is non zero.
       
   270     Forcing flush frequently degrades the compression ratio, so this parameter
       
   271     should be set only when necessary (in interactive applications).
       
   272     Some output may be provided even if flush is not set.
       
   273 
       
   274   Before the call of deflate(), the application should ensure that at least
       
   275   one of the actions is possible, by providing more input and/or consuming
       
   276   more output, and updating avail_in or avail_out accordingly; avail_out
       
   277   should never be zero before the call. The application can consume the
       
   278   compressed output when it wants, for example when the output buffer is full
       
   279   (avail_out == 0), or after each call of deflate(). If deflate returns Z_OK
       
   280   and with zero avail_out, it must be called again after making room in the
       
   281   output buffer because there might be more output pending.
       
   282 
       
   283     Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to
       
   284   decide how much data to accumualte before producing output, in order to
       
   285   maximize compression.
       
   286 
       
   287     If the parameter flush is set to Z_SYNC_FLUSH, all pending output is
       
   288   flushed to the output buffer and the output is aligned on a byte boundary, so
       
   289   that the decompressor can get all input data available so far. (In particular
       
   290   avail_in is zero after the call if enough output space has been provided
       
   291   before the call.)  Flushing may degrade compression for some compression
       
   292   algorithms and so it should be used only when necessary.
       
   293 
       
   294     If flush is set to Z_FULL_FLUSH, all output is flushed as with
       
   295   Z_SYNC_FLUSH, and the compression state is reset so that decompression can
       
   296   restart from this point if previous compressed data has been damaged or if
       
   297   random access is desired. Using Z_FULL_FLUSH too often can seriously degrade
       
   298   compression.
       
   299 
       
   300     If deflate returns with avail_out == 0, this function must be called again
       
   301   with the same value of the flush parameter and more output space (updated
       
   302   avail_out), until the flush is complete (deflate returns with non-zero
       
   303   avail_out). In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that
       
   304   avail_out is greater than six to avoid repeated flush markers due to
       
   305   avail_out == 0 on return.
       
   306 
       
   307     If the parameter flush is set to Z_FINISH, pending input is processed,
       
   308   pending output is flushed and deflate returns with Z_STREAM_END if there
       
   309   was enough output space; if deflate returns with Z_OK, this function must be
       
   310   called again with Z_FINISH and more output space (updated avail_out) but no
       
   311   more input data, until it returns with Z_STREAM_END or an error. After
       
   312   deflate has returned Z_STREAM_END, the only possible operations on the
       
   313   stream are deflateReset or deflateEnd.
       
   314 
       
   315     Z_FINISH can be used immediately after deflateInit if all the compression
       
   316   is to be done in a single step. In this case, avail_out must be at least
       
   317   the value returned by deflateBound (see below). If deflate does not return
       
   318   Z_STREAM_END, then it must be called again as described above.
       
   319 
       
   320     deflate() sets strm->adler to the adler32 checksum of all input read
       
   321   so far (that is, total_in bytes).
       
   322 
       
   323     deflate() may update strm->data_type if it can make a good guess about
       
   324   the input data type (Z_BINARY or Z_TEXT). In doubt, the data is considered
       
   325   binary. This field is only for information purposes and does not affect
       
   326   the compression algorithm in any manner.
       
   327 
       
   328     deflate() returns Z_OK if some progress has been made (more input
       
   329   processed or more output produced), Z_STREAM_END if all input has been
       
   330   consumed and all output has been produced (only when flush is set to
       
   331   Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
       
   332   if next_in or next_out was NULL), Z_BUF_ERROR if no progress is possible
       
   333   (for example avail_in or avail_out was zero). Note that Z_BUF_ERROR is not
       
   334   fatal, and deflate() can be called again with more input and more output
       
   335   space to continue compressing.
       
   336 */
       
   337 
       
   338 
       
   339 ZEXTERN int Q_ZEXPORT deflateEnd OF((z_streamp strm));
       
   340 /*
       
   341      All dynamically allocated data structures for this stream are freed.
       
   342    This function discards any unprocessed input and does not flush any
       
   343    pending output.
       
   344 
       
   345      deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
       
   346    stream state was inconsistent, Z_DATA_ERROR if the stream was freed
       
   347    prematurely (some input or output was discarded). In the error case,
       
   348    msg may be set but then points to a static string (which must not be
       
   349    deallocated).
       
   350 */
       
   351 
       
   352 
       
   353 /*
       
   354 ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm));
       
   355 
       
   356      Initializes the internal stream state for decompression. The fields
       
   357    next_in, avail_in, zalloc, zfree and opaque must be initialized before by
       
   358    the caller. If next_in is not Z_NULL and avail_in is large enough (the exact
       
   359    value depends on the compression method), inflateInit determines the
       
   360    compression method from the zlib header and allocates all data structures
       
   361    accordingly; otherwise the allocation will be deferred to the first call of
       
   362    inflate.  If zalloc and zfree are set to Z_NULL, inflateInit updates them to
       
   363    use default allocation functions.
       
   364 
       
   365      inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
       
   366    memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
       
   367    version assumed by the caller.  msg is set to null if there is no error
       
   368    message. inflateInit does not perform any decompression apart from reading
       
   369    the zlib header if present: this will be done by inflate().  (So next_in and
       
   370    avail_in may be modified, but next_out and avail_out are unchanged.)
       
   371 */
       
   372 
       
   373 
       
   374 ZEXTERN int Q_ZEXPORT inflate OF((z_streamp strm, int flush));
       
   375 /*
       
   376     inflate decompresses as much data as possible, and stops when the input
       
   377   buffer becomes empty or the output buffer becomes full. It may introduce
       
   378   some output latency (reading input without producing any output) except when
       
   379   forced to flush.
       
   380 
       
   381   The detailed semantics are as follows. inflate performs one or both of the
       
   382   following actions:
       
   383 
       
   384   - Decompress more input starting at next_in and update next_in and avail_in
       
   385     accordingly. If not all input can be processed (because there is not
       
   386     enough room in the output buffer), next_in is updated and processing
       
   387     will resume at this point for the next call of inflate().
       
   388 
       
   389   - Provide more output starting at next_out and update next_out and avail_out
       
   390     accordingly.  inflate() provides as much output as possible, until there
       
   391     is no more input data or no more space in the output buffer (see below
       
   392     about the flush parameter).
       
   393 
       
   394   Before the call of inflate(), the application should ensure that at least
       
   395   one of the actions is possible, by providing more input and/or consuming
       
   396   more output, and updating the next_* and avail_* values accordingly.
       
   397   The application can consume the uncompressed output when it wants, for
       
   398   example when the output buffer is full (avail_out == 0), or after each
       
   399   call of inflate(). If inflate returns Z_OK and with zero avail_out, it
       
   400   must be called again after making room in the output buffer because there
       
   401   might be more output pending.
       
   402 
       
   403     The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH,
       
   404   Z_FINISH, or Z_BLOCK. Z_SYNC_FLUSH requests that inflate() flush as much
       
   405   output as possible to the output buffer. Z_BLOCK requests that inflate() stop
       
   406   if and when it gets to the next deflate block boundary. When decoding the
       
   407   zlib or gzip format, this will cause inflate() to return immediately after
       
   408   the header and before the first block. When doing a raw inflate, inflate()
       
   409   will go ahead and process the first block, and will return when it gets to
       
   410   the end of that block, or when it runs out of data.
       
   411 
       
   412     The Z_BLOCK option assists in appending to or combining deflate streams.
       
   413   Also to assist in this, on return inflate() will set strm->data_type to the
       
   414   number of unused bits in the last byte taken from strm->next_in, plus 64
       
   415   if inflate() is currently decoding the last block in the deflate stream,
       
   416   plus 128 if inflate() returned immediately after decoding an end-of-block
       
   417   code or decoding the complete header up to just before the first byte of the
       
   418   deflate stream. The end-of-block will not be indicated until all of the
       
   419   uncompressed data from that block has been written to strm->next_out.  The
       
   420   number of unused bits may in general be greater than seven, except when
       
   421   bit 7 of data_type is set, in which case the number of unused bits will be
       
   422   less than eight.
       
   423 
       
   424     inflate() should normally be called until it returns Z_STREAM_END or an
       
   425   error. However if all decompression is to be performed in a single step
       
   426   (a single call of inflate), the parameter flush should be set to
       
   427   Z_FINISH. In this case all pending input is processed and all pending
       
   428   output is flushed; avail_out must be large enough to hold all the
       
   429   uncompressed data. (The size of the uncompressed data may have been saved
       
   430   by the compressor for this purpose.) The next operation on this stream must
       
   431   be inflateEnd to deallocate the decompression state. The use of Z_FINISH
       
   432   is never required, but can be used to inform inflate that a faster approach
       
   433   may be used for the single inflate() call.
       
   434 
       
   435      In this implementation, inflate() always flushes as much output as
       
   436   possible to the output buffer, and always uses the faster approach on the
       
   437   first call. So the only effect of the flush parameter in this implementation
       
   438   is on the return value of inflate(), as noted below, or when it returns early
       
   439   because Z_BLOCK is used.
       
   440 
       
   441      If a preset dictionary is needed after this call (see inflateSetDictionary
       
   442   below), inflate sets strm->adler to the adler32 checksum of the dictionary
       
   443   chosen by the compressor and returns Z_NEED_DICT; otherwise it sets
       
   444   strm->adler to the adler32 checksum of all output produced so far (that is,
       
   445   total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described
       
   446   below. At the end of the stream, inflate() checks that its computed adler32
       
   447   checksum is equal to that saved by the compressor and returns Z_STREAM_END
       
   448   only if the checksum is correct.
       
   449 
       
   450     inflate() will decompress and check either zlib-wrapped or gzip-wrapped
       
   451   deflate data.  The header type is detected automatically.  Any information
       
   452   contained in the gzip header is not retained, so applications that need that
       
   453   information should instead use raw inflate, see inflateInit2() below, or
       
   454   inflateBack() and perform their own processing of the gzip header and
       
   455   trailer.
       
   456 
       
   457     inflate() returns Z_OK if some progress has been made (more input processed
       
   458   or more output produced), Z_STREAM_END if the end of the compressed data has
       
   459   been reached and all uncompressed output has been produced, Z_NEED_DICT if a
       
   460   preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
       
   461   corrupted (input stream not conforming to the zlib format or incorrect check
       
   462   value), Z_STREAM_ERROR if the stream structure was inconsistent (for example
       
   463   if next_in or next_out was NULL), Z_MEM_ERROR if there was not enough memory,
       
   464   Z_BUF_ERROR if no progress is possible or if there was not enough room in the
       
   465   output buffer when Z_FINISH is used. Note that Z_BUF_ERROR is not fatal, and
       
   466   inflate() can be called again with more input and more output space to
       
   467   continue decompressing. If Z_DATA_ERROR is returned, the application may then
       
   468   call inflateSync() to look for a good compression block if a partial recovery
       
   469   of the data is desired.
       
   470 */
       
   471 
       
   472 
       
   473 ZEXTERN int Q_ZEXPORT inflateEnd OF((z_streamp strm));
       
   474 /*
       
   475      All dynamically allocated data structures for this stream are freed.
       
   476    This function discards any unprocessed input and does not flush any
       
   477    pending output.
       
   478 
       
   479      inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state
       
   480    was inconsistent. In the error case, msg may be set but then points to a
       
   481    static string (which must not be deallocated).
       
   482 */
       
   483 
       
   484                         /* Advanced functions */
       
   485 
       
   486 /*
       
   487     The following functions are needed only in some special applications.
       
   488 */
       
   489 
       
   490 /*
       
   491 ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm,
       
   492                                      int  level,
       
   493                                      int  method,
       
   494                                      int  windowBits,
       
   495                                      int  memLevel,
       
   496                                      int  strategy));
       
   497 
       
   498      This is another version of deflateInit with more compression options. The
       
   499    fields next_in, zalloc, zfree and opaque must be initialized before by
       
   500    the caller.
       
   501 
       
   502      The method parameter is the compression method. It must be Z_DEFLATED in
       
   503    this version of the library.
       
   504 
       
   505      The windowBits parameter is the base two logarithm of the window size
       
   506    (the size of the history buffer). It should be in the range 8..15 for this
       
   507    version of the library. Larger values of this parameter result in better
       
   508    compression at the expense of memory usage. The default value is 15 if
       
   509    deflateInit is used instead.
       
   510 
       
   511      windowBits can also be -8..-15 for raw deflate. In this case, -windowBits
       
   512    determines the window size. deflate() will then generate raw deflate data
       
   513    with no zlib header or trailer, and will not compute an adler32 check value.
       
   514 
       
   515      windowBits can also be greater than 15 for optional gzip encoding. Add
       
   516    16 to windowBits to write a simple gzip header and trailer around the
       
   517    compressed data instead of a zlib wrapper. The gzip header will have no
       
   518    file name, no extra data, no comment, no modification time (set to zero),
       
   519    no header crc, and the operating system will be set to 255 (unknown).  If a
       
   520    gzip stream is being written, strm->adler is a crc32 instead of an adler32.
       
   521 
       
   522      The memLevel parameter specifies how much memory should be allocated
       
   523    for the internal compression state. memLevel=1 uses minimum memory but
       
   524    is slow and reduces compression ratio; memLevel=9 uses maximum memory
       
   525    for optimal speed. The default value is 8. See zconf.h for total memory
       
   526    usage as a function of windowBits and memLevel.
       
   527 
       
   528      The strategy parameter is used to tune the compression algorithm. Use the
       
   529    value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
       
   530    filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no
       
   531    string match), or Z_RLE to limit match distances to one (run-length
       
   532    encoding). Filtered data consists mostly of small values with a somewhat
       
   533    random distribution. In this case, the compression algorithm is tuned to
       
   534    compress them better. The effect of Z_FILTERED is to force more Huffman
       
   535    coding and less string matching; it is somewhat intermediate between
       
   536    Z_DEFAULT and Z_HUFFMAN_ONLY. Z_RLE is designed to be almost as fast as
       
   537    Z_HUFFMAN_ONLY, but give better compression for PNG image data. The strategy
       
   538    parameter only affects the compression ratio but not the correctness of the
       
   539    compressed output even if it is not set appropriately.  Z_FIXED prevents the
       
   540    use of dynamic Huffman codes, allowing for a simpler decoder for special
       
   541    applications.
       
   542 
       
   543       deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
       
   544    memory, Z_STREAM_ERROR if a parameter is invalid (such as an invalid
       
   545    method). msg is set to null if there is no error message.  deflateInit2 does
       
   546    not perform any compression: this will be done by deflate().
       
   547 */
       
   548 
       
   549 ZEXTERN int Q_ZEXPORT deflateSetDictionary OF((z_streamp strm,
       
   550                                              const Bytef *dictionary,
       
   551                                              uInt  dictLength));
       
   552 /*
       
   553      Initializes the compression dictionary from the given byte sequence
       
   554    without producing any compressed output. This function must be called
       
   555    immediately after deflateInit, deflateInit2 or deflateReset, before any
       
   556    call of deflate. The compressor and decompressor must use exactly the same
       
   557    dictionary (see inflateSetDictionary).
       
   558 
       
   559      The dictionary should consist of strings (byte sequences) that are likely
       
   560    to be encountered later in the data to be compressed, with the most commonly
       
   561    used strings preferably put towards the end of the dictionary. Using a
       
   562    dictionary is most useful when the data to be compressed is short and can be
       
   563    predicted with good accuracy; the data can then be compressed better than
       
   564    with the default empty dictionary.
       
   565 
       
   566      Depending on the size of the compression data structures selected by
       
   567    deflateInit or deflateInit2, a part of the dictionary may in effect be
       
   568    discarded, for example if the dictionary is larger than the window size in
       
   569    deflate or deflate2. Thus the strings most likely to be useful should be
       
   570    put at the end of the dictionary, not at the front. In addition, the
       
   571    current implementation of deflate will use at most the window size minus
       
   572    262 bytes of the provided dictionary.
       
   573 
       
   574      Upon return of this function, strm->adler is set to the adler32 value
       
   575    of the dictionary; the decompressor may later use this value to determine
       
   576    which dictionary has been used by the compressor. (The adler32 value
       
   577    applies to the whole dictionary even if only a subset of the dictionary is
       
   578    actually used by the compressor.) If a raw deflate was requested, then the
       
   579    adler32 value is not computed and strm->adler is not set.
       
   580 
       
   581      deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
       
   582    parameter is invalid (such as NULL dictionary) or the stream state is
       
   583    inconsistent (for example if deflate has already been called for this stream
       
   584    or if the compression method is bsort). deflateSetDictionary does not
       
   585    perform any compression: this will be done by deflate().
       
   586 */
       
   587 
       
   588 ZEXTERN int Q_ZEXPORT deflateCopy OF((z_streamp dest,
       
   589                                     z_streamp source));
       
   590 /*
       
   591      Sets the destination stream as a complete copy of the source stream.
       
   592 
       
   593      This function can be useful when several compression strategies will be
       
   594    tried, for example when there are several ways of pre-processing the input
       
   595    data with a filter. The streams that will be discarded should then be freed
       
   596    by calling deflateEnd.  Note that deflateCopy duplicates the internal
       
   597    compression state which can be quite large, so this strategy is slow and
       
   598    can consume lots of memory.
       
   599 
       
   600      deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
       
   601    enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
       
   602    (such as zalloc being NULL). msg is left unchanged in both source and
       
   603    destination.
       
   604 */
       
   605 
       
   606 ZEXTERN int Q_ZEXPORT deflateReset OF((z_streamp strm));
       
   607 /*
       
   608      This function is equivalent to deflateEnd followed by deflateInit,
       
   609    but does not free and reallocate all the internal compression state.
       
   610    The stream will keep the same compression level and any other attributes
       
   611    that may have been set by deflateInit2.
       
   612 
       
   613       deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
       
   614    stream state was inconsistent (such as zalloc or state being NULL).
       
   615 */
       
   616 
       
   617 ZEXTERN int Q_ZEXPORT deflateParams OF((z_streamp strm,
       
   618                                       int level,
       
   619                                       int strategy));
       
   620 /*
       
   621      Dynamically update the compression level and compression strategy.  The
       
   622    interpretation of level and strategy is as in deflateInit2.  This can be
       
   623    used to switch between compression and straight copy of the input data, or
       
   624    to switch to a different kind of input data requiring a different
       
   625    strategy. If the compression level is changed, the input available so far
       
   626    is compressed with the old level (and may be flushed); the new level will
       
   627    take effect only at the next call of deflate().
       
   628 
       
   629      Before the call of deflateParams, the stream state must be set as for
       
   630    a call of deflate(), since the currently available input may have to
       
   631    be compressed and flushed. In particular, strm->avail_out must be non-zero.
       
   632 
       
   633      deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source
       
   634    stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR
       
   635    if strm->avail_out was zero.
       
   636 */
       
   637 
       
   638 ZEXTERN int ZEXPORT deflateTune OF((z_streamp strm,
       
   639                                     int good_length,
       
   640                                     int max_lazy,
       
   641                                     int nice_length,
       
   642                                     int max_chain));
       
   643 /*
       
   644      Fine tune deflate's internal compression parameters.  This should only be
       
   645    used by someone who understands the algorithm used by zlib's deflate for
       
   646    searching for the best matching string, and even then only by the most
       
   647    fanatic optimizer trying to squeeze out the last compressed bit for their
       
   648    specific input data.  Read the deflate.c source code for the meaning of the
       
   649    max_lazy, good_length, nice_length, and max_chain parameters.
       
   650 
       
   651      deflateTune() can be called after deflateInit() or deflateInit2(), and
       
   652    returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream.
       
   653  */
       
   654 
       
   655 ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm,
       
   656                                        uLong sourceLen));
       
   657 /*
       
   658      deflateBound() returns an upper bound on the compressed size after
       
   659    deflation of sourceLen bytes.  It must be called after deflateInit()
       
   660    or deflateInit2().  This would be used to allocate an output buffer
       
   661    for deflation in a single pass, and so would be called before deflate().
       
   662 */
       
   663 
       
   664 ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm,
       
   665                                      int bits,
       
   666                                      int value));
       
   667 /*
       
   668      deflatePrime() inserts bits in the deflate output stream.  The intent
       
   669   is that this function is used to start off the deflate output with the
       
   670   bits leftover from a previous deflate stream when appending to it.  As such,
       
   671   this function can only be used for raw deflate, and must be used before the
       
   672   first deflate() call after a deflateInit2() or deflateReset().  bits must be
       
   673   less than or equal to 16, and that many of the least significant bits of
       
   674   value will be inserted in the output.
       
   675 
       
   676       deflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source
       
   677    stream state was inconsistent.
       
   678 */
       
   679 
       
   680 ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm,
       
   681                                          gz_headerp head));
       
   682 /*
       
   683       deflateSetHeader() provides gzip header information for when a gzip
       
   684    stream is requested by deflateInit2().  deflateSetHeader() may be called
       
   685    after deflateInit2() or deflateReset() and before the first call of
       
   686    deflate().  The text, time, os, extra field, name, and comment information
       
   687    in the provided gz_header structure are written to the gzip header (xflag is
       
   688    ignored -- the extra flags are set according to the compression level).  The
       
   689    caller must assure that, if not Z_NULL, name and comment are terminated with
       
   690    a zero byte, and that if extra is not Z_NULL, that extra_len bytes are
       
   691    available there.  If hcrc is true, a gzip header crc is included.  Note that
       
   692    the current versions of the command-line version of gzip (up through version
       
   693    1.3.x) do not support header crc's, and will report that it is a "multi-part
       
   694    gzip file" and give up.
       
   695 
       
   696       If deflateSetHeader is not used, the default gzip header has text false,
       
   697    the time set to zero, and os set to 255, with no extra, name, or comment
       
   698    fields.  The gzip header is returned to the default state by deflateReset().
       
   699 
       
   700       deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
       
   701    stream state was inconsistent.
       
   702 */
       
   703 
       
   704 /*
       
   705 ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm,
       
   706                                      int  windowBits));
       
   707 
       
   708      This is another version of inflateInit with an extra parameter. The
       
   709    fields next_in, avail_in, zalloc, zfree and opaque must be initialized
       
   710    before by the caller.
       
   711 
       
   712      The windowBits parameter is the base two logarithm of the maximum window
       
   713    size (the size of the history buffer).  It should be in the range 8..15 for
       
   714    this version of the library. The default value is 15 if inflateInit is used
       
   715    instead. windowBits must be greater than or equal to the windowBits value
       
   716    provided to deflateInit2() while compressing, or it must be equal to 15 if
       
   717    deflateInit2() was not used. If a compressed stream with a larger window
       
   718    size is given as input, inflate() will return with the error code
       
   719    Z_DATA_ERROR instead of trying to allocate a larger window.
       
   720 
       
   721      windowBits can also be -8..-15 for raw inflate. In this case, -windowBits
       
   722    determines the window size. inflate() will then process raw deflate data,
       
   723    not looking for a zlib or gzip header, not generating a check value, and not
       
   724    looking for any check values for comparison at the end of the stream. This
       
   725    is for use with other formats that use the deflate compressed data format
       
   726    such as zip.  Those formats provide their own check values. If a custom
       
   727    format is developed using the raw deflate format for compressed data, it is
       
   728    recommended that a check value such as an adler32 or a crc32 be applied to
       
   729    the uncompressed data as is done in the zlib, gzip, and zip formats.  For
       
   730    most applications, the zlib format should be used as is. Note that comments
       
   731    above on the use in deflateInit2() applies to the magnitude of windowBits.
       
   732 
       
   733      windowBits can also be greater than 15 for optional gzip decoding. Add
       
   734    32 to windowBits to enable zlib and gzip decoding with automatic header
       
   735    detection, or add 16 to decode only the gzip format (the zlib format will
       
   736    return a Z_DATA_ERROR).  If a gzip stream is being decoded, strm->adler is
       
   737    a crc32 instead of an adler32.
       
   738 
       
   739      inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
       
   740    memory, Z_STREAM_ERROR if a parameter is invalid (such as a null strm). msg
       
   741    is set to null if there is no error message.  inflateInit2 does not perform
       
   742    any decompression apart from reading the zlib header if present: this will
       
   743    be done by inflate(). (So next_in and avail_in may be modified, but next_out
       
   744    and avail_out are unchanged.)
       
   745 */
       
   746 
       
   747 ZEXTERN int Q_ZEXPORT inflateSetDictionary OF((z_streamp strm,
       
   748                                              const Bytef *dictionary,
       
   749                                              uInt  dictLength));
       
   750 /*
       
   751      Initializes the decompression dictionary from the given uncompressed byte
       
   752    sequence. This function must be called immediately after a call of inflate,
       
   753    if that call returned Z_NEED_DICT. The dictionary chosen by the compressor
       
   754    can be determined from the adler32 value returned by that call of inflate.
       
   755    The compressor and decompressor must use exactly the same dictionary (see
       
   756    deflateSetDictionary).  For raw inflate, this function can be called
       
   757    immediately after inflateInit2() or inflateReset() and before any call of
       
   758    inflate() to set the dictionary.  The application must insure that the
       
   759    dictionary that was used for compression is provided.
       
   760 
       
   761      inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
       
   762    parameter is invalid (such as NULL dictionary) or the stream state is
       
   763    inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
       
   764    expected one (incorrect adler32 value). inflateSetDictionary does not
       
   765    perform any decompression: this will be done by subsequent calls of
       
   766    inflate().
       
   767 */
       
   768 
       
   769 ZEXTERN int Q_ZEXPORT inflateSync OF((z_streamp strm));
       
   770 /*
       
   771     Skips invalid compressed data until a full flush point (see above the
       
   772   description of deflate with Z_FULL_FLUSH) can be found, or until all
       
   773   available input is skipped. No output is provided.
       
   774 
       
   775     inflateSync returns Z_OK if a full flush point has been found, Z_BUF_ERROR
       
   776   if no more input was provided, Z_DATA_ERROR if no flush point has been found,
       
   777   or Z_STREAM_ERROR if the stream structure was inconsistent. In the success
       
   778   case, the application may save the current current value of total_in which
       
   779   indicates where valid compressed data was found. In the error case, the
       
   780   application may repeatedly call inflateSync, providing more input each time,
       
   781   until success or end of the input data.
       
   782 */
       
   783 
       
   784 ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest,
       
   785                                     z_streamp source));
       
   786 /*
       
   787      Sets the destination stream as a complete copy of the source stream.
       
   788 
       
   789      This function can be useful when randomly accessing a large stream.  The
       
   790    first pass through the stream can periodically record the inflate state,
       
   791    allowing restarting inflate at those points when randomly accessing the
       
   792    stream.
       
   793 
       
   794      inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
       
   795    enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
       
   796    (such as zalloc being NULL). msg is left unchanged in both source and
       
   797    destination.
       
   798 */
       
   799 
       
   800 ZEXTERN int Q_ZEXPORT inflateReset OF((z_streamp strm));
       
   801 /*
       
   802      This function is equivalent to inflateEnd followed by inflateInit,
       
   803    but does not free and reallocate all the internal decompression state.
       
   804    The stream will keep attributes that may have been set by inflateInit2.
       
   805 
       
   806       inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
       
   807    stream state was inconsistent (such as zalloc or state being NULL).
       
   808 */
       
   809 
       
   810 ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm,
       
   811                                      int bits,
       
   812                                      int value));
       
   813 /*
       
   814      This function inserts bits in the inflate input stream.  The intent is
       
   815   that this function is used to start inflating at a bit position in the
       
   816   middle of a byte.  The provided bits will be used before any bytes are used
       
   817   from next_in.  This function should only be used with raw inflate, and
       
   818   should be used before the first inflate() call after inflateInit2() or
       
   819   inflateReset().  bits must be less than or equal to 16, and that many of the
       
   820   least significant bits of value will be inserted in the input.
       
   821 
       
   822       inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source
       
   823    stream state was inconsistent.
       
   824 */
       
   825 
       
   826 ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm,
       
   827                                          gz_headerp head));
       
   828 /*
       
   829       inflateGetHeader() requests that gzip header information be stored in the
       
   830    provided gz_header structure.  inflateGetHeader() may be called after
       
   831    inflateInit2() or inflateReset(), and before the first call of inflate().
       
   832    As inflate() processes the gzip stream, head->done is zero until the header
       
   833    is completed, at which time head->done is set to one.  If a zlib stream is
       
   834    being decoded, then head->done is set to -1 to indicate that there will be
       
   835    no gzip header information forthcoming.  Note that Z_BLOCK can be used to
       
   836    force inflate() to return immediately after header processing is complete
       
   837    and before any actual data is decompressed.
       
   838 
       
   839       The text, time, xflags, and os fields are filled in with the gzip header
       
   840    contents.  hcrc is set to true if there is a header CRC.  (The header CRC
       
   841    was valid if done is set to one.)  If extra is not Z_NULL, then extra_max
       
   842    contains the maximum number of bytes to write to extra.  Once done is true,
       
   843    extra_len contains the actual extra field length, and extra contains the
       
   844    extra field, or that field truncated if extra_max is less than extra_len.
       
   845    If name is not Z_NULL, then up to name_max characters are written there,
       
   846    terminated with a zero unless the length is greater than name_max.  If
       
   847    comment is not Z_NULL, then up to comm_max characters are written there,
       
   848    terminated with a zero unless the length is greater than comm_max.  When
       
   849    any of extra, name, or comment are not Z_NULL and the respective field is
       
   850    not present in the header, then that field is set to Z_NULL to signal its
       
   851    absence.  This allows the use of deflateSetHeader() with the returned
       
   852    structure to duplicate the header.  However if those fields are set to
       
   853    allocated memory, then the application will need to save those pointers
       
   854    elsewhere so that they can be eventually freed.
       
   855 
       
   856       If inflateGetHeader is not used, then the header information is simply
       
   857    discarded.  The header is always checked for validity, including the header
       
   858    CRC if present.  inflateReset() will reset the process to discard the header
       
   859    information.  The application would need to call inflateGetHeader() again to
       
   860    retrieve the header from the next gzip stream.
       
   861 
       
   862       inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
       
   863    stream state was inconsistent.
       
   864 */
       
   865 
       
   866 /*
       
   867 ZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits,
       
   868                                         unsigned char FAR *window));
       
   869 
       
   870      Initialize the internal stream state for decompression using inflateBack()
       
   871    calls.  The fields zalloc, zfree and opaque in strm must be initialized
       
   872    before the call.  If zalloc and zfree are Z_NULL, then the default library-
       
   873    derived memory allocation routines are used.  windowBits is the base two
       
   874    logarithm of the window size, in the range 8..15.  window is a caller
       
   875    supplied buffer of that size.  Except for special applications where it is
       
   876    assured that deflate was used with small window sizes, windowBits must be 15
       
   877    and a 32K byte window must be supplied to be able to decompress general
       
   878    deflate streams.
       
   879 
       
   880      See inflateBack() for the usage of these routines.
       
   881 
       
   882      inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of
       
   883    the paramaters are invalid, Z_MEM_ERROR if the internal state could not
       
   884    be allocated, or Z_VERSION_ERROR if the version of the library does not
       
   885    match the version of the header file.
       
   886 */
       
   887 
       
   888 typedef unsigned (*in_func) OF((void FAR *, unsigned char FAR * FAR *));
       
   889 typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned));
       
   890 
       
   891 ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm,
       
   892                                     in_func in, void FAR *in_desc,
       
   893                                     out_func out, void FAR *out_desc));
       
   894 /*
       
   895      inflateBack() does a raw inflate with a single call using a call-back
       
   896    interface for input and output.  This is more efficient than inflate() for
       
   897    file i/o applications in that it avoids copying between the output and the
       
   898    sliding window by simply making the window itself the output buffer.  This
       
   899    function trusts the application to not change the output buffer passed by
       
   900    the output function, at least until inflateBack() returns.
       
   901 
       
   902      inflateBackInit() must be called first to allocate the internal state
       
   903    and to initialize the state with the user-provided window buffer.
       
   904    inflateBack() may then be used multiple times to inflate a complete, raw
       
   905    deflate stream with each call.  inflateBackEnd() is then called to free
       
   906    the allocated state.
       
   907 
       
   908      A raw deflate stream is one with no zlib or gzip header or trailer.
       
   909    This routine would normally be used in a utility that reads zip or gzip
       
   910    files and writes out uncompressed files.  The utility would decode the
       
   911    header and process the trailer on its own, hence this routine expects
       
   912    only the raw deflate stream to decompress.  This is different from the
       
   913    normal behavior of inflate(), which expects either a zlib or gzip header and
       
   914    trailer around the deflate stream.
       
   915 
       
   916      inflateBack() uses two subroutines supplied by the caller that are then
       
   917    called by inflateBack() for input and output.  inflateBack() calls those
       
   918    routines until it reads a complete deflate stream and writes out all of the
       
   919    uncompressed data, or until it encounters an error.  The function's
       
   920    parameters and return types are defined above in the in_func and out_func
       
   921    typedefs.  inflateBack() will call in(in_desc, &buf) which should return the
       
   922    number of bytes of provided input, and a pointer to that input in buf.  If
       
   923    there is no input available, in() must return zero--buf is ignored in that
       
   924    case--and inflateBack() will return a buffer error.  inflateBack() will call
       
   925    out(out_desc, buf, len) to write the uncompressed data buf[0..len-1].  out()
       
   926    should return zero on success, or non-zero on failure.  If out() returns
       
   927    non-zero, inflateBack() will return with an error.  Neither in() nor out()
       
   928    are permitted to change the contents of the window provided to
       
   929    inflateBackInit(), which is also the buffer that out() uses to write from.
       
   930    The length written by out() will be at most the window size.  Any non-zero
       
   931    amount of input may be provided by in().
       
   932 
       
   933      For convenience, inflateBack() can be provided input on the first call by
       
   934    setting strm->next_in and strm->avail_in.  If that input is exhausted, then
       
   935    in() will be called.  Therefore strm->next_in must be initialized before
       
   936    calling inflateBack().  If strm->next_in is Z_NULL, then in() will be called
       
   937    immediately for input.  If strm->next_in is not Z_NULL, then strm->avail_in
       
   938    must also be initialized, and then if strm->avail_in is not zero, input will
       
   939    initially be taken from strm->next_in[0 .. strm->avail_in - 1].
       
   940 
       
   941      The in_desc and out_desc parameters of inflateBack() is passed as the
       
   942    first parameter of in() and out() respectively when they are called.  These
       
   943    descriptors can be optionally used to pass any information that the caller-
       
   944    supplied in() and out() functions need to do their job.
       
   945 
       
   946      On return, inflateBack() will set strm->next_in and strm->avail_in to
       
   947    pass back any unused input that was provided by the last in() call.  The
       
   948    return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR
       
   949    if in() or out() returned an error, Z_DATA_ERROR if there was a format
       
   950    error in the deflate stream (in which case strm->msg is set to indicate the
       
   951    nature of the error), or Z_STREAM_ERROR if the stream was not properly
       
   952    initialized.  In the case of Z_BUF_ERROR, an input or output error can be
       
   953    distinguished using strm->next_in which will be Z_NULL only if in() returned
       
   954    an error.  If strm->next is not Z_NULL, then the Z_BUF_ERROR was due to
       
   955    out() returning non-zero.  (in() will always be called before out(), so
       
   956    strm->next_in is assured to be defined if out() returns non-zero.)  Note
       
   957    that inflateBack() cannot return Z_OK.
       
   958 */
       
   959 
       
   960 ZEXTERN int ZEXPORT inflateBackEnd OF((z_streamp strm));
       
   961 /*
       
   962      All memory allocated by inflateBackInit() is freed.
       
   963 
       
   964      inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream
       
   965    state was inconsistent.
       
   966 */
       
   967 
       
   968 ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void));
       
   969 /* Return flags indicating compile-time options.
       
   970 
       
   971     Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other:
       
   972      1.0: size of uInt
       
   973      3.2: size of uLong
       
   974      5.4: size of voidpf (pointer)
       
   975      7.6: size of z_off_t
       
   976 
       
   977     Compiler, assembler, and debug options:
       
   978      8: DEBUG
       
   979      9: ASMV or ASMINF -- use ASM code
       
   980      10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention
       
   981      11: 0 (reserved)
       
   982 
       
   983     One-time table building (smaller code, but not thread-safe if true):
       
   984      12: BUILDFIXED -- build static block decoding tables when needed
       
   985      13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed
       
   986      14,15: 0 (reserved)
       
   987 
       
   988     Library content (indicates missing functionality):
       
   989      16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking
       
   990                           deflate code when not needed)
       
   991      17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect
       
   992                     and decode gzip streams (to avoid linking crc code)
       
   993      18-19: 0 (reserved)
       
   994 
       
   995     Operation variations (changes in library functionality):
       
   996      20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate
       
   997      21: FASTEST -- deflate algorithm with only one, lowest compression level
       
   998      22,23: 0 (reserved)
       
   999 
       
  1000     The sprintf variant used by gzprintf (zero is best):
       
  1001      24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format
       
  1002      25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure!
       
  1003      26: 0 = returns value, 1 = void -- 1 means inferred string length returned
       
  1004 
       
  1005     Remainder:
       
  1006      27-31: 0 (reserved)
       
  1007  */
       
  1008 
       
  1009 
       
  1010                         /* utility functions */
       
  1011 
       
  1012 /*
       
  1013      The following utility functions are implemented on top of the
       
  1014    basic stream-oriented functions. To simplify the interface, some
       
  1015    default options are assumed (compression level and memory usage,
       
  1016    standard memory allocation functions). The source code of these
       
  1017    utility functions can easily be modified if you need special options.
       
  1018 */
       
  1019 
       
  1020 ZEXTERN int Q_ZEXPORT compress OF((Bytef *dest,   uLongf *destLen,
       
  1021                                  const Bytef *source, uLong sourceLen));
       
  1022 /*
       
  1023      Compresses the source buffer into the destination buffer.  sourceLen is
       
  1024    the byte length of the source buffer. Upon entry, destLen is the total
       
  1025    size of the destination buffer, which must be at least the value returned
       
  1026    by compressBound(sourceLen). Upon exit, destLen is the actual size of the
       
  1027    compressed buffer.
       
  1028      This function can be used to compress a whole file at once if the
       
  1029    input file is mmap'ed.
       
  1030      compress returns Z_OK if success, Z_MEM_ERROR if there was not
       
  1031    enough memory, Z_BUF_ERROR if there was not enough room in the output
       
  1032    buffer.
       
  1033 */
       
  1034 
       
  1035 ZEXTERN int Q_ZEXPORT compress2 OF((Bytef *dest,   uLongf *destLen,
       
  1036                                   const Bytef *source, uLong sourceLen,
       
  1037                                   int level));
       
  1038 /*
       
  1039      Compresses the source buffer into the destination buffer. The level
       
  1040    parameter has the same meaning as in deflateInit.  sourceLen is the byte
       
  1041    length of the source buffer. Upon entry, destLen is the total size of the
       
  1042    destination buffer, which must be at least the value returned by
       
  1043    compressBound(sourceLen). Upon exit, destLen is the actual size of the
       
  1044    compressed buffer.
       
  1045 
       
  1046      compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
       
  1047    memory, Z_BUF_ERROR if there was not enough room in the output buffer,
       
  1048    Z_STREAM_ERROR if the level parameter is invalid.
       
  1049 */
       
  1050 
       
  1051 ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen));
       
  1052 /*
       
  1053      compressBound() returns an upper bound on the compressed size after
       
  1054    compress() or compress2() on sourceLen bytes.  It would be used before
       
  1055    a compress() or compress2() call to allocate the destination buffer.
       
  1056 */
       
  1057 
       
  1058 ZEXTERN int Q_ZEXPORT uncompress OF((Bytef *dest,   uLongf *destLen,
       
  1059                                    const Bytef *source, uLong sourceLen));
       
  1060 /*
       
  1061      Decompresses the source buffer into the destination buffer.  sourceLen is
       
  1062    the byte length of the source buffer. Upon entry, destLen is the total
       
  1063    size of the destination buffer, which must be large enough to hold the
       
  1064    entire uncompressed data. (The size of the uncompressed data must have
       
  1065    been saved previously by the compressor and transmitted to the decompressor
       
  1066    by some mechanism outside the scope of this compression library.)
       
  1067    Upon exit, destLen is the actual size of the compressed buffer.
       
  1068      This function can be used to decompress a whole file at once if the
       
  1069    input file is mmap'ed.
       
  1070 
       
  1071      uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
       
  1072    enough memory, Z_BUF_ERROR if there was not enough room in the output
       
  1073    buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete.
       
  1074 */
       
  1075 
       
  1076 
       
  1077 typedef voidp gzFile;
       
  1078 
       
  1079 ZEXTERN gzFile Q_ZEXPORT gzopen  OF((const char *path, const char *mode));
       
  1080 /*
       
  1081      Opens a gzip (.gz) file for reading or writing. The mode parameter
       
  1082    is as in fopen ("rb" or "wb") but can also include a compression level
       
  1083    ("wb9") or a strategy: 'f' for filtered data as in "wb6f", 'h' for
       
  1084    Huffman only compression as in "wb1h", or 'R' for run-length encoding
       
  1085    as in "wb1R". (See the description of deflateInit2 for more information
       
  1086    about the strategy parameter.)
       
  1087 
       
  1088      gzopen can be used to read a file which is not in gzip format; in this
       
  1089    case gzread will directly read from the file without decompression.
       
  1090 
       
  1091      gzopen returns NULL if the file could not be opened or if there was
       
  1092    insufficient memory to allocate the (de)compression state; errno
       
  1093    can be checked to distinguish the two cases (if errno is zero, the
       
  1094    zlib error is Z_MEM_ERROR).  */
       
  1095 
       
  1096 ZEXTERN gzFile Q_ZEXPORT gzdopen  OF((int fd, const char *mode));
       
  1097 /*
       
  1098      gzdopen() associates a gzFile with the file descriptor fd.  File
       
  1099    descriptors are obtained from calls like open, dup, creat, pipe or
       
  1100    fileno (in the file has been previously opened with fopen).
       
  1101    The mode parameter is as in gzopen.
       
  1102      The next call of gzclose on the returned gzFile will also close the
       
  1103    file descriptor fd, just like fclose(fdopen(fd), mode) closes the file
       
  1104    descriptor fd. If you want to keep fd open, use gzdopen(dup(fd), mode).
       
  1105      gzdopen returns NULL if there was insufficient memory to allocate
       
  1106    the (de)compression state.
       
  1107 */
       
  1108 
       
  1109 ZEXTERN int Q_ZEXPORT gzsetparams OF((gzFile file, int level, int strategy));
       
  1110 /*
       
  1111      Dynamically update the compression level or strategy. See the description
       
  1112    of deflateInit2 for the meaning of these parameters.
       
  1113      gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not
       
  1114    opened for writing.
       
  1115 */
       
  1116 
       
  1117 ZEXTERN int Q_ZEXPORT    gzread  OF((gzFile file, voidp buf, unsigned len));
       
  1118 /*
       
  1119      Reads the given number of uncompressed bytes from the compressed file.
       
  1120    If the input file was not in gzip format, gzread copies the given number
       
  1121    of bytes into the buffer.
       
  1122      gzread returns the number of uncompressed bytes actually read (0 for
       
  1123    end of file, -1 for error). */
       
  1124 
       
  1125 ZEXTERN int Q_ZEXPORT    gzwrite OF((gzFile file,
       
  1126                                    voidpc buf, unsigned len));
       
  1127 /*
       
  1128      Writes the given number of uncompressed bytes into the compressed file.
       
  1129    gzwrite returns the number of uncompressed bytes actually written
       
  1130    (0 in case of error).
       
  1131 */
       
  1132 
       
  1133 ZEXTERN int Q_ZEXPORT gzprintf OF((gzFile file, const char *format, ...));
       
  1134 /*
       
  1135      Converts, formats, and writes the args to the compressed file under
       
  1136    control of the format string, as in fprintf. gzprintf returns the number of
       
  1137    uncompressed bytes actually written (0 in case of error).  The number of
       
  1138    uncompressed bytes written is limited to 4095. The caller should assure that
       
  1139    this limit is not exceeded. If it is exceeded, then gzprintf() will return
       
  1140    return an error (0) with nothing written. In this case, there may also be a
       
  1141    buffer overflow with unpredictable consequences, which is possible only if
       
  1142    zlib was compiled with the insecure functions sprintf() or vsprintf()
       
  1143    because the secure snprintf() or vsnprintf() functions were not available.
       
  1144 */
       
  1145 
       
  1146 ZEXTERN int Q_ZEXPORT gzputs OF((gzFile file, const char *s));
       
  1147 /*
       
  1148       Writes the given null-terminated string to the compressed file, excluding
       
  1149    the terminating null character.
       
  1150       gzputs returns the number of characters written, or -1 in case of error.
       
  1151 */
       
  1152 
       
  1153 ZEXTERN Q_ZEXPORT char * gzgets OF((gzFile file, char *buf, int len));
       
  1154 /*
       
  1155       Reads bytes from the compressed file until len-1 characters are read, or
       
  1156    a newline character is read and transferred to buf, or an end-of-file
       
  1157    condition is encountered.  The string is then terminated with a null
       
  1158    character.
       
  1159       gzgets returns buf, or Z_NULL in case of error.
       
  1160 */
       
  1161 
       
  1162 ZEXTERN int Q_ZEXPORT    gzputc OF((gzFile file, int c));
       
  1163 /*
       
  1164       Writes c, converted to an unsigned char, into the compressed file.
       
  1165    gzputc returns the value that was written, or -1 in case of error.
       
  1166 */
       
  1167 
       
  1168 ZEXTERN int Q_ZEXPORT    gzgetc OF((gzFile file));
       
  1169 /*
       
  1170       Reads one byte from the compressed file. gzgetc returns this byte
       
  1171    or -1 in case of end of file or error.
       
  1172 */
       
  1173 
       
  1174 ZEXTERN int ZEXPORT    gzungetc OF((int c, gzFile file));
       
  1175 /*
       
  1176       Push one character back onto the stream to be read again later.
       
  1177    Only one character of push-back is allowed.  gzungetc() returns the
       
  1178    character pushed, or -1 on failure.  gzungetc() will fail if a
       
  1179    character has been pushed but not read yet, or if c is -1. The pushed
       
  1180    character will be discarded if the stream is repositioned with gzseek()
       
  1181    or gzrewind().
       
  1182 */
       
  1183 
       
  1184 ZEXTERN int Q_ZEXPORT    gzflush OF((gzFile file, int flush));
       
  1185 /*
       
  1186      Flushes all pending output into the compressed file. The parameter
       
  1187    flush is as in the deflate() function. The return value is the zlib
       
  1188    error number (see function gzerror below). gzflush returns Z_OK if
       
  1189    the flush parameter is Z_FINISH and all output could be flushed.
       
  1190      gzflush should be called only when strictly necessary because it can
       
  1191    degrade compression.
       
  1192 */
       
  1193 
       
  1194 ZEXTERN z_off_t Q_ZEXPORT    gzseek OF((gzFile file,
       
  1195                                       z_off_t offset, int whence));
       
  1196 /*
       
  1197       Sets the starting position for the next gzread or gzwrite on the
       
  1198    given compressed file. The offset represents a number of bytes in the
       
  1199    uncompressed data stream. The whence parameter is defined as in lseek(2);
       
  1200    the value SEEK_END is not supported.
       
  1201      If the file is opened for reading, this function is emulated but can be
       
  1202    extremely slow. If the file is opened for writing, only forward seeks are
       
  1203    supported; gzseek then compresses a sequence of zeroes up to the new
       
  1204    starting position.
       
  1205 
       
  1206       gzseek returns the resulting offset location as measured in bytes from
       
  1207    the beginning of the uncompressed stream, or -1 in case of error, in
       
  1208    particular if the file is opened for writing and the new starting position
       
  1209    would be before the current position.
       
  1210 */
       
  1211 
       
  1212 ZEXTERN int Q_ZEXPORT    gzrewind OF((gzFile file));
       
  1213 /*
       
  1214      Rewinds the given file. This function is supported only for reading.
       
  1215 
       
  1216    gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET)
       
  1217 */
       
  1218 
       
  1219 ZEXTERN z_off_t Q_ZEXPORT    gztell OF((gzFile file));
       
  1220 /*
       
  1221      Returns the starting position for the next gzread or gzwrite on the
       
  1222    given compressed file. This position represents a number of bytes in the
       
  1223    uncompressed data stream.
       
  1224 
       
  1225    gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)
       
  1226 */
       
  1227 
       
  1228 ZEXTERN int Q_ZEXPORT gzeof OF((gzFile file));
       
  1229 /*
       
  1230      Returns 1 when EOF has previously been detected reading the given
       
  1231    input stream, otherwise zero.
       
  1232 */
       
  1233 
       
  1234 ZEXTERN int ZEXPORT gzdirect OF((gzFile file));
       
  1235 /*
       
  1236      Returns 1 if file is being read directly without decompression, otherwise
       
  1237    zero.
       
  1238 */
       
  1239 
       
  1240 ZEXTERN int Q_ZEXPORT    gzclose OF((gzFile file));
       
  1241 /*
       
  1242      Flushes all pending output if necessary, closes the compressed file
       
  1243    and deallocates all the (de)compression state. The return value is the zlib
       
  1244    error number (see function gzerror below).
       
  1245 */
       
  1246 
       
  1247 ZEXTERN Q_ZEXPORT const char * gzerror OF((gzFile file, int *errnum));
       
  1248 /*
       
  1249      Returns the error message for the last error which occurred on the
       
  1250    given compressed file. errnum is set to zlib error number. If an
       
  1251    error occurred in the file system and not in the compression library,
       
  1252    errnum is set to Z_ERRNO and the application may consult errno
       
  1253    to get the exact error code.
       
  1254 */
       
  1255 
       
  1256 ZEXTERN void ZEXPORT gzclearerr OF((gzFile file));
       
  1257 /*
       
  1258      Clears the error and end-of-file flags for file. This is analogous to the
       
  1259    clearerr() function in stdio. This is useful for continuing to read a gzip
       
  1260    file that is being written concurrently.
       
  1261 */
       
  1262 
       
  1263                         /* checksum functions */
       
  1264 
       
  1265 /*
       
  1266      These functions are not related to compression but are exported
       
  1267    anyway because they might be useful in applications using the
       
  1268    compression library.
       
  1269 */
       
  1270 
       
  1271 ZEXTERN uLong Q_ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len));
       
  1272 /*
       
  1273      Update a running Adler-32 checksum with the bytes buf[0..len-1] and
       
  1274    return the updated checksum. If buf is NULL, this function returns
       
  1275    the required initial value for the checksum.
       
  1276    An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
       
  1277    much faster. Usage example:
       
  1278 
       
  1279      uLong adler = adler32(0L, Z_NULL, 0);
       
  1280 
       
  1281      while (read_buffer(buffer, length) != EOF) {
       
  1282        adler = adler32(adler, buffer, length);
       
  1283      }
       
  1284      if (adler != original_adler) error();
       
  1285 */
       
  1286 
       
  1287 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong adler1, uLong adler2,
       
  1288                                           z_off_t len2));
       
  1289 /*
       
  1290      Combine two Adler-32 checksums into one.  For two sequences of bytes, seq1
       
  1291    and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for
       
  1292    each, adler1 and adler2.  adler32_combine() returns the Adler-32 checksum of
       
  1293    seq1 and seq2 concatenated, requiring only adler1, adler2, and len2.
       
  1294 */
       
  1295 
       
  1296 ZEXTERN uLong Q_ZEXPORT crc32   OF((uLong crc, const Bytef *buf, uInt len));
       
  1297 /*
       
  1298      Update a running CRC-32 with the bytes buf[0..len-1] and return the
       
  1299    updated CRC-32. If buf is NULL, this function returns the required initial
       
  1300    value for the for the crc. Pre- and post-conditioning (one's complement) is
       
  1301    performed within this function so it shouldn't be done by the application.
       
  1302    Usage example:
       
  1303 
       
  1304      uLong crc = crc32(0L, Z_NULL, 0);
       
  1305 
       
  1306      while (read_buffer(buffer, length) != EOF) {
       
  1307        crc = crc32(crc, buffer, length);
       
  1308      }
       
  1309      if (crc != original_crc) error();
       
  1310 */
       
  1311 
       
  1312 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2));
       
  1313 
       
  1314 /*
       
  1315      Combine two CRC-32 check values into one.  For two sequences of bytes,
       
  1316    seq1 and seq2 with lengths len1 and len2, CRC-32 check values were
       
  1317    calculated for each, crc1 and crc2.  crc32_combine() returns the CRC-32
       
  1318    check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and
       
  1319    len2.
       
  1320 */
       
  1321 
       
  1322 
       
  1323                         /* various hacks, don't look :) */
       
  1324 
       
  1325 /* deflateInit and inflateInit are macros to allow checking the zlib version
       
  1326  * and the compiler's view of z_stream:
       
  1327  */
       
  1328 ZEXTERN int Q_ZEXPORT deflateInit_ OF((z_streamp strm, int level,
       
  1329                                      const char *version, int stream_size));
       
  1330 ZEXTERN int Q_ZEXPORT inflateInit_ OF((z_streamp strm,
       
  1331                                      const char *version, int stream_size));
       
  1332 ZEXTERN int Q_ZEXPORT deflateInit2_ OF((z_streamp strm, int  level, int  method,
       
  1333                                       int windowBits, int memLevel,
       
  1334                                       int strategy, const char *version,
       
  1335                                       int stream_size));
       
  1336 ZEXTERN int Q_ZEXPORT inflateInit2_ OF((z_streamp strm, int  windowBits,
       
  1337                                       const char *version, int stream_size));
       
  1338 ZEXTERN int ZEXPORT inflateBackInit_ OF((z_streamp strm, int windowBits,
       
  1339                                          unsigned char FAR *window,
       
  1340                                          const char *version,
       
  1341                                          int stream_size));
       
  1342 #define deflateInit(strm, level) \
       
  1343         deflateInit_((strm), (level),       ZLIB_VERSION, sizeof(z_stream))
       
  1344 #define inflateInit(strm) \
       
  1345         inflateInit_((strm),                ZLIB_VERSION, sizeof(z_stream))
       
  1346 #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
       
  1347         deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
       
  1348                       (strategy),           ZLIB_VERSION, sizeof(z_stream))
       
  1349 #define inflateInit2(strm, windowBits) \
       
  1350         inflateInit2_((strm), (windowBits), ZLIB_VERSION, sizeof(z_stream))
       
  1351 #define inflateBackInit(strm, windowBits, window) \
       
  1352         inflateBackInit_((strm), (windowBits), (window), \
       
  1353         ZLIB_VERSION, sizeof(z_stream))
       
  1354 
       
  1355 
       
  1356 #if !defined(ZUTIL_H) && !defined(NO_DUMMY_DECL)
       
  1357     struct internal_state {int dummy;}; /* hack for buggy compilers */
       
  1358 #endif
       
  1359 
       
  1360 ZEXTERN Q_ZEXPORT const char   * zError           OF((int));
       
  1361 ZEXTERN int            Q_ZEXPORT inflateSyncPoint OF((z_streamp z));
       
  1362 ZEXTERN Q_ZEXPORT const uLongf * get_crc_table    OF((void));
       
  1363 
       
  1364 #ifdef __cplusplus
       
  1365 }
       
  1366 #endif
       
  1367 
       
  1368 #endif /* ZLIB_H */