zlib.h

00001 /* zlib.h -- interface of the 'zlib' general purpose compression library
00002   version 1.2.8, April 28th, 2013
00003 
00004   Copyright (C) 1995-2013 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://tools.ietf.org/html/rfc1950
00028   (zlib format), rfc1951 (deflate format) and rfc1952 (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 "1.2.8"
00041 #define ZLIB_VERNUM 0x1280
00042 #define ZLIB_VER_MAJOR 1
00043 #define ZLIB_VER_MINOR 2
00044 #define ZLIB_VER_REVISION 8
00045 #define ZLIB_VER_SUBREVISION 0
00046 
00047 /*
00048     The 'zlib' compression library provides in-memory compression and
00049   decompression functions, including integrity checks of the uncompressed data.
00050   This version of the library supports only one compression method (deflation)
00051   but other algorithms will be added later and will have the same stream
00052   interface.
00053 
00054     Compression can be done in a single step if the buffers are large enough,
00055   or can be done by repeated calls of the compression function.  In the latter
00056   case, the application must provide more input and/or consume the output
00057   (providing more output space) before each call.
00058 
00059     The compressed data format used by default by the in-memory functions is
00060   the zlib format, which is a zlib wrapper documented in RFC 1950, wrapped
00061   around a deflate stream, which is itself documented in RFC 1951.
00062 
00063     The library also supports reading and writing files in gzip (.gz) format
00064   with an interface similar to that of stdio using the functions that start
00065   with "gz".  The gzip format is different from the zlib format.  gzip is a
00066   gzip wrapper, documented in RFC 1952, wrapped around a deflate stream.
00067 
00068     This library can optionally read and write gzip streams in memory as well.
00069 
00070     The zlib format was designed to be compact and fast for use in memory
00071   and on communications channels.  The gzip format was designed for single-
00072   file compression on file systems, has a larger header than zlib to maintain
00073   directory information, and uses a different, slower check method than zlib.
00074 
00075     The library does not install any signal handler.  The decoder checks
00076   the consistency of the compressed data, so the library should never crash
00077   even in case of corrupted input.
00078 */
00079 
00080 typedef voidpf (*alloc_func) OF((voidpf opaque, uInt items, uInt size));
00081 typedef void   (*free_func)  OF((voidpf opaque, voidpf address));
00082 
00083 struct internal_state;
00084 
00085 typedef struct z_stream_s {
00086     z_const Bytef *next_in;     /* next input byte */
00087     uInt     avail_in;  /* number of bytes available at next_in */
00088     uLong    total_in;  /* total number of input bytes read so far */
00089 
00090     Bytef    *next_out; /* next output byte should be put there */
00091     uInt     avail_out; /* remaining free space at next_out */
00092     uLong    total_out; /* total number of bytes output so far */
00093 
00094     z_const char *msg;  /* last error message, NULL if no error */
00095     struct internal_state FAR *state; /* not visible by applications */
00096 
00097     alloc_func zalloc;  /* used to allocate the internal state */
00098     free_func  zfree;   /* used to free the internal state */
00099     voidpf     opaque;  /* private data object passed to zalloc and zfree */
00100 
00101     int     data_type;  /* best guess about the data type: binary or text */
00102     uLong   adler;      /* adler32 value of the uncompressed data */
00103     uLong   reserved;   /* reserved for future use */
00104 } z_stream;
00105 
00106 typedef z_stream FAR *z_streamp;
00107 
00108 /*
00109      gzip header information passed to and from zlib routines.  See RFC 1952
00110   for more details on the meanings of these fields.
00111 */
00112 typedef struct gz_header_s {
00113     int     text;       /* true if compressed data believed to be text */
00114     uLong   time;       /* modification time */
00115     int     xflags;     /* extra flags (not used when writing a gzip file) */
00116     int     os;         /* operating system */
00117     Bytef   *extra;     /* pointer to extra field or Z_NULL if none */
00118     uInt    extra_len;  /* extra field length (valid if extra != Z_NULL) */
00119     uInt    extra_max;  /* space at extra (only when reading header) */
00120     Bytef   *name;      /* pointer to zero-terminated file name or Z_NULL */
00121     uInt    name_max;   /* space at name (only when reading header) */
00122     Bytef   *comment;   /* pointer to zero-terminated comment or Z_NULL */
00123     uInt    comm_max;   /* space at comment (only when reading header) */
00124     int     hcrc;       /* true if there was or will be a header crc */
00125     int     done;       /* true when done reading gzip header (not used
00126                            when writing a gzip file) */
00127 } gz_header;
00128 
00129 typedef gz_header FAR *gz_headerp;
00130 
00131 /*
00132      The application must update next_in and avail_in when avail_in has dropped
00133    to zero.  It must update next_out and avail_out when avail_out has dropped
00134    to zero.  The application must initialize zalloc, zfree and opaque before
00135    calling the init function.  All other fields are set by the compression
00136    library and must not be updated by the application.
00137 
00138      The opaque value provided by the application will be passed as the first
00139    parameter for calls of zalloc and zfree.  This can be useful for custom
00140    memory management.  The compression library attaches no meaning to the
00141    opaque value.
00142 
00143      zalloc must return Z_NULL if there is not enough memory for the object.
00144    If zlib is used in a multi-threaded application, zalloc and zfree must be
00145    thread safe.
00146 
00147      On 16-bit systems, the functions zalloc and zfree must be able to allocate
00148    exactly 65536 bytes, but will not be required to allocate more than this if
00149    the symbol MAXSEG_64K is defined (see zconf.h).  WARNING: On MSDOS, pointers
00150    returned by zalloc for objects of exactly 65536 bytes *must* have their
00151    offset normalized to zero.  The default allocation function provided by this
00152    library ensures this (see zutil.c).  To reduce memory requirements and avoid
00153    any allocation of 64K objects, at the expense of compression ratio, compile
00154    the library with -DMAX_WBITS=14 (see zconf.h).
00155 
00156      The fields total_in and total_out can be used for statistics or progress
00157    reports.  After compression, total_in holds the total size of the
00158    uncompressed data and may be saved for use in the decompressor (particularly
00159    if the decompressor wants to decompress everything in a single step).
00160 */
00161 
00162                         /* constants */
00163 
00164 #define Z_NO_FLUSH      0
00165 #define Z_PARTIAL_FLUSH 1
00166 #define Z_SYNC_FLUSH    2
00167 #define Z_FULL_FLUSH    3
00168 #define Z_FINISH        4
00169 #define Z_BLOCK         5
00170 #define Z_TREES         6
00171 /* Allowed flush values; see deflate() and inflate() below for details */
00172 
00173 #define Z_OK            0
00174 #define Z_STREAM_END    1
00175 #define Z_NEED_DICT     2
00176 #define Z_ERRNO        (-1)
00177 #define Z_STREAM_ERROR (-2)
00178 #define Z_DATA_ERROR   (-3)
00179 #define Z_MEM_ERROR    (-4)
00180 #define Z_BUF_ERROR    (-5)
00181 #define Z_VERSION_ERROR (-6)
00182 /* Return codes for the compression/decompression functions. Negative values
00183  * are errors, positive values are used for special but normal events.
00184  */
00185 
00186 #define Z_NO_COMPRESSION         0
00187 #define Z_BEST_SPEED             1
00188 #define Z_BEST_COMPRESSION       9
00189 #define Z_DEFAULT_COMPRESSION  (-1)
00190 /* compression levels */
00191 
00192 #define Z_FILTERED            1
00193 #define Z_HUFFMAN_ONLY        2
00194 #define Z_RLE                 3
00195 #define Z_FIXED               4
00196 #define Z_DEFAULT_STRATEGY    0
00197 /* compression strategy; see deflateInit2() below for details */
00198 
00199 #define Z_BINARY   0
00200 #define Z_TEXT     1
00201 #define Z_ASCII    Z_TEXT   /* for compatibility with 1.2.2 and earlier */
00202 #define Z_UNKNOWN  2
00203 /* Possible values of the data_type field (though see inflate()) */
00204 
00205 #define Z_DEFLATED   8
00206 /* The deflate compression method (the only one supported in this version) */
00207 
00208 #define Z_NULL  0  /* for initializing zalloc, zfree, opaque */
00209 
00210 #define zlib_version zlibVersion()
00211 /* for compatibility with versions < 1.0.2 */
00212 
00213 
00214                         /* basic functions */
00215 
00216 ZEXTERN const char * ZEXPORT zlibVersion OF((void));
00217 /* The application can compare zlibVersion and ZLIB_VERSION for consistency.
00218    If the first character differs, the library code actually used is not
00219    compatible with the zlib.h header file used by the application.  This check
00220    is automatically made by deflateInit and inflateInit.
00221  */
00222 
00223 /*
00224 ZEXTERN int ZEXPORT deflateInit OF((z_streamp strm, int level));
00225 
00226      Initializes the internal stream state for compression.  The fields
00227    zalloc, zfree and opaque must be initialized before by the caller.  If
00228    zalloc and zfree are set to Z_NULL, deflateInit updates them to use default
00229    allocation functions.
00230 
00231      The compression level must be Z_DEFAULT_COMPRESSION, or between 0 and 9:
00232    1 gives best speed, 9 gives best compression, 0 gives no compression at all
00233    (the input data is simply copied a block at a time).  Z_DEFAULT_COMPRESSION
00234    requests a default compromise between speed and compression (currently
00235    equivalent to level 6).
00236 
00237      deflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
00238    memory, Z_STREAM_ERROR if level is not a valid compression level, or
00239    Z_VERSION_ERROR if the zlib library version (zlib_version) is incompatible
00240    with the version assumed by the caller (ZLIB_VERSION).  msg is set to null
00241    if there is no error message.  deflateInit does not perform any compression:
00242    this will be done by deflate().
00243 */
00244 
00245 
00246 ZEXTERN int ZEXPORT deflate OF((z_streamp strm, int flush));
00247 /*
00248     deflate compresses as much data as possible, and stops when the input
00249   buffer becomes empty or the output buffer becomes full.  It may introduce
00250   some output latency (reading input without producing any output) except when
00251   forced to flush.
00252 
00253     The detailed semantics are as follows.  deflate performs one or both of the
00254   following actions:
00255 
00256   - Compress more input starting at next_in and update next_in and avail_in
00257     accordingly.  If not all input can be processed (because there is not
00258     enough room in the output buffer), next_in and avail_in are updated and
00259     processing will resume at this point for the next call of deflate().
00260 
00261   - Provide more output starting at next_out and update next_out and avail_out
00262     accordingly.  This action is forced if the parameter flush is non zero.
00263     Forcing flush frequently degrades the compression ratio, so this parameter
00264     should be set only when necessary (in interactive applications).  Some
00265     output may be provided even if flush is not set.
00266 
00267     Before the call of deflate(), the application should ensure that at least
00268   one of the actions is possible, by providing more input and/or consuming more
00269   output, and updating avail_in or avail_out accordingly; avail_out should
00270   never be zero before the call.  The application can consume the compressed
00271   output when it wants, for example when the output buffer is full (avail_out
00272   == 0), or after each call of deflate().  If deflate returns Z_OK and with
00273   zero avail_out, it must be called again after making room in the output
00274   buffer because there might be more output pending.
00275 
00276     Normally the parameter flush is set to Z_NO_FLUSH, which allows deflate to
00277   decide how much data to accumulate before producing output, in order to
00278   maximize compression.
00279 
00280     If the parameter flush is set to Z_SYNC_FLUSH, all pending output is
00281   flushed to the output buffer and the output is aligned on a byte boundary, so
00282   that the decompressor can get all input data available so far.  (In
00283   particular avail_in is zero after the call if enough output space has been
00284   provided before the call.) Flushing may degrade compression for some
00285   compression algorithms and so it should be used only when necessary.  This
00286   completes the current deflate block and follows it with an empty stored block
00287   that is three bits plus filler bits to the next byte, followed by four bytes
00288   (00 00 ff ff).
00289 
00290     If flush is set to Z_PARTIAL_FLUSH, all pending output is flushed to the
00291   output buffer, but the output is not aligned to a byte boundary.  All of the
00292   input data so far will be available to the decompressor, as for Z_SYNC_FLUSH.
00293   This completes the current deflate block and follows it with an empty fixed
00294   codes block that is 10 bits long.  This assures that enough bytes are output
00295   in order for the decompressor to finish the block before the empty fixed code
00296   block.
00297 
00298     If flush is set to Z_BLOCK, a deflate block is completed and emitted, as
00299   for Z_SYNC_FLUSH, but the output is not aligned on a byte boundary, and up to
00300   seven bits of the current block are held to be written as the next byte after
00301   the next deflate block is completed.  In this case, the decompressor may not
00302   be provided enough bits at this point in order to complete decompression of
00303   the data provided so far to the compressor.  It may need to wait for the next
00304   block to be emitted.  This is for advanced applications that need to control
00305   the emission of deflate blocks.
00306 
00307     If flush is set to Z_FULL_FLUSH, all output is flushed as with
00308   Z_SYNC_FLUSH, and the compression state is reset so that decompression can
00309   restart from this point if previous compressed data has been damaged or if
00310   random access is desired.  Using Z_FULL_FLUSH too often can seriously degrade
00311   compression.
00312 
00313     If deflate returns with avail_out == 0, this function must be called again
00314   with the same value of the flush parameter and more output space (updated
00315   avail_out), until the flush is complete (deflate returns with non-zero
00316   avail_out).  In the case of a Z_FULL_FLUSH or Z_SYNC_FLUSH, make sure that
00317   avail_out is greater than six to avoid repeated flush markers due to
00318   avail_out == 0 on return.
00319 
00320     If the parameter flush is set to Z_FINISH, pending input is processed,
00321   pending output is flushed and deflate returns with Z_STREAM_END if there was
00322   enough output space; if deflate returns with Z_OK, this function must be
00323   called again with Z_FINISH and more output space (updated avail_out) but no
00324   more input data, until it returns with Z_STREAM_END or an error.  After
00325   deflate has returned Z_STREAM_END, the only possible operations on the stream
00326   are deflateReset or deflateEnd.
00327 
00328     Z_FINISH can be used immediately after deflateInit if all the compression
00329   is to be done in a single step.  In this case, avail_out must be at least the
00330   value returned by deflateBound (see below).  Then deflate is guaranteed to
00331   return Z_STREAM_END.  If not enough output space is provided, deflate will
00332   not return Z_STREAM_END, and it must be called again as described above.
00333 
00334     deflate() sets strm->adler to the adler32 checksum of all input read
00335   so far (that is, total_in bytes).
00336 
00337     deflate() may update strm->data_type if it can make a good guess about
00338   the input data type (Z_BINARY or Z_TEXT).  In doubt, the data is considered
00339   binary.  This field is only for information purposes and does not affect the
00340   compression algorithm in any manner.
00341 
00342     deflate() returns Z_OK if some progress has been made (more input
00343   processed or more output produced), Z_STREAM_END if all input has been
00344   consumed and all output has been produced (only when flush is set to
00345   Z_FINISH), Z_STREAM_ERROR if the stream state was inconsistent (for example
00346   if next_in or next_out was Z_NULL), Z_BUF_ERROR if no progress is possible
00347   (for example avail_in or avail_out was zero).  Note that Z_BUF_ERROR is not
00348   fatal, and deflate() can be called again with more input and more output
00349   space to continue compressing.
00350 */
00351 
00352 
00353 ZEXTERN int ZEXPORT deflateEnd OF((z_streamp strm));
00354 /*
00355      All dynamically allocated data structures for this stream are freed.
00356    This function discards any unprocessed input and does not flush any pending
00357    output.
00358 
00359      deflateEnd returns Z_OK if success, Z_STREAM_ERROR if the
00360    stream state was inconsistent, Z_DATA_ERROR if the stream was freed
00361    prematurely (some input or output was discarded).  In the error case, msg
00362    may be set but then points to a static string (which must not be
00363    deallocated).
00364 */
00365 
00366 
00367 /*
00368 ZEXTERN int ZEXPORT inflateInit OF((z_streamp strm));
00369 
00370      Initializes the internal stream state for decompression.  The fields
00371    next_in, avail_in, zalloc, zfree and opaque must be initialized before by
00372    the caller.  If next_in is not Z_NULL and avail_in is large enough (the
00373    exact value depends on the compression method), inflateInit determines the
00374    compression method from the zlib header and allocates all data structures
00375    accordingly; otherwise the allocation will be deferred to the first call of
00376    inflate.  If zalloc and zfree are set to Z_NULL, inflateInit updates them to
00377    use default allocation functions.
00378 
00379      inflateInit returns Z_OK if success, Z_MEM_ERROR if there was not enough
00380    memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
00381    version assumed by the caller, or Z_STREAM_ERROR if the parameters are
00382    invalid, such as a null pointer to the structure.  msg is set to null if
00383    there is no error message.  inflateInit does not perform any decompression
00384    apart from possibly reading the zlib header if present: actual decompression
00385    will be done by inflate().  (So next_in and avail_in may be modified, but
00386    next_out and avail_out are unused and unchanged.) The current implementation
00387    of inflateInit() does not process any header information -- that is deferred
00388    until inflate() is called.
00389 */
00390 
00391 
00392 ZEXTERN int ZEXPORT inflate OF((z_streamp strm, int flush));
00393 /*
00394     inflate decompresses as much data as possible, and stops when the input
00395   buffer becomes empty or the output buffer becomes full.  It may introduce
00396   some output latency (reading input without producing any output) except when
00397   forced to flush.
00398 
00399   The detailed semantics are as follows.  inflate performs one or both of the
00400   following actions:
00401 
00402   - Decompress more input starting at next_in and update next_in and avail_in
00403     accordingly.  If not all input can be processed (because there is not
00404     enough room in the output buffer), next_in is updated and processing will
00405     resume at this point for the next call of inflate().
00406 
00407   - Provide more output starting at next_out and update next_out and avail_out
00408     accordingly.  inflate() provides as much output as possible, until there is
00409     no more input data or no more space in the output buffer (see below about
00410     the flush parameter).
00411 
00412     Before the call of inflate(), the application should ensure that at least
00413   one of the actions is possible, by providing more input and/or consuming more
00414   output, and updating the next_* and avail_* values accordingly.  The
00415   application can consume the uncompressed output when it wants, for example
00416   when the output buffer is full (avail_out == 0), or after each call of
00417   inflate().  If inflate returns Z_OK and with zero avail_out, it must be
00418   called again after making room in the output buffer because there might be
00419   more output pending.
00420 
00421     The flush parameter of inflate() can be Z_NO_FLUSH, Z_SYNC_FLUSH, Z_FINISH,
00422   Z_BLOCK, or Z_TREES.  Z_SYNC_FLUSH requests that inflate() flush as much
00423   output as possible to the output buffer.  Z_BLOCK requests that inflate()
00424   stop if and when it gets to the next deflate block boundary.  When decoding
00425   the zlib or gzip format, this will cause inflate() to return immediately
00426   after the header and before the first block.  When doing a raw inflate,
00427   inflate() will go ahead and process the first block, and will return when it
00428   gets to the end of that block, or when it runs out of data.
00429 
00430     The Z_BLOCK option assists in appending to or combining deflate streams.
00431   Also to assist in this, on return inflate() will set strm->data_type to the
00432   number of unused bits in the last byte taken from strm->next_in, plus 64 if
00433   inflate() is currently decoding the last block in the deflate stream, plus
00434   128 if inflate() returned immediately after decoding an end-of-block code or
00435   decoding the complete header up to just before the first byte of the deflate
00436   stream.  The end-of-block will not be indicated until all of the uncompressed
00437   data from that block has been written to strm->next_out.  The number of
00438   unused bits may in general be greater than seven, except when bit 7 of
00439   data_type is set, in which case the number of unused bits will be less than
00440   eight.  data_type is set as noted here every time inflate() returns for all
00441   flush options, and so can be used to determine the amount of currently
00442   consumed input in bits.
00443 
00444     The Z_TREES option behaves as Z_BLOCK does, but it also returns when the
00445   end of each deflate block header is reached, before any actual data in that
00446   block is decoded.  This allows the caller to determine the length of the
00447   deflate block header for later use in random access within a deflate block.
00448   256 is added to the value of strm->data_type when inflate() returns
00449   immediately after reaching the end of the deflate block header.
00450 
00451     inflate() should normally be called until it returns Z_STREAM_END or an
00452   error.  However if all decompression is to be performed in a single step (a
00453   single call of inflate), the parameter flush should be set to Z_FINISH.  In
00454   this case all pending input is processed and all pending output is flushed;
00455   avail_out must be large enough to hold all of the uncompressed data for the
00456   operation to complete.  (The size of the uncompressed data may have been
00457   saved by the compressor for this purpose.) The use of Z_FINISH is not
00458   required to perform an inflation in one step.  However it may be used to
00459   inform inflate that a faster approach can be used for the single inflate()
00460   call.  Z_FINISH also informs inflate to not maintain a sliding window if the
00461   stream completes, which reduces inflate's memory footprint.  If the stream
00462   does not complete, either because not all of the stream is provided or not
00463   enough output space is provided, then a sliding window will be allocated and
00464   inflate() can be called again to continue the operation as if Z_NO_FLUSH had
00465   been used.
00466 
00467      In this implementation, inflate() always flushes as much output as
00468   possible to the output buffer, and always uses the faster approach on the
00469   first call.  So the effects of the flush parameter in this implementation are
00470   on the return value of inflate() as noted below, when inflate() returns early
00471   when Z_BLOCK or Z_TREES is used, and when inflate() avoids the allocation of
00472   memory for a sliding window when Z_FINISH is used.
00473 
00474      If a preset dictionary is needed after this call (see inflateSetDictionary
00475   below), inflate sets strm->adler to the Adler-32 checksum of the dictionary
00476   chosen by the compressor and returns Z_NEED_DICT; otherwise it sets
00477   strm->adler to the Adler-32 checksum of all output produced so far (that is,
00478   total_out bytes) and returns Z_OK, Z_STREAM_END or an error code as described
00479   below.  At the end of the stream, inflate() checks that its computed adler32
00480   checksum is equal to that saved by the compressor and returns Z_STREAM_END
00481   only if the checksum is correct.
00482 
00483     inflate() can decompress and check either zlib-wrapped or gzip-wrapped
00484   deflate data.  The header type is detected automatically, if requested when
00485   initializing with inflateInit2().  Any information contained in the gzip
00486   header is not retained, so applications that need that information should
00487   instead use raw inflate, see inflateInit2() below, or inflateBack() and
00488   perform their own processing of the gzip header and trailer.  When processing
00489   gzip-wrapped deflate data, strm->adler32 is set to the CRC-32 of the output
00490   producted so far.  The CRC-32 is checked against the gzip trailer.
00491 
00492     inflate() returns Z_OK if some progress has been made (more input processed
00493   or more output produced), Z_STREAM_END if the end of the compressed data has
00494   been reached and all uncompressed output has been produced, Z_NEED_DICT if a
00495   preset dictionary is needed at this point, Z_DATA_ERROR if the input data was
00496   corrupted (input stream not conforming to the zlib format or incorrect check
00497   value), Z_STREAM_ERROR if the stream structure was inconsistent (for example
00498   next_in or next_out was Z_NULL), Z_MEM_ERROR if there was not enough memory,
00499   Z_BUF_ERROR if no progress is possible or if there was not enough room in the
00500   output buffer when Z_FINISH is used.  Note that Z_BUF_ERROR is not fatal, and
00501   inflate() can be called again with more input and more output space to
00502   continue decompressing.  If Z_DATA_ERROR is returned, the application may
00503   then call inflateSync() to look for a good compression block if a partial
00504   recovery of the data is desired.
00505 */
00506 
00507 
00508 ZEXTERN int ZEXPORT inflateEnd OF((z_streamp strm));
00509 /*
00510      All dynamically allocated data structures for this stream are freed.
00511    This function discards any unprocessed input and does not flush any pending
00512    output.
00513 
00514      inflateEnd returns Z_OK if success, Z_STREAM_ERROR if the stream state
00515    was inconsistent.  In the error case, msg may be set but then points to a
00516    static string (which must not be deallocated).
00517 */
00518 
00519 
00520                         /* Advanced functions */
00521 
00522 /*
00523     The following functions are needed only in some special applications.
00524 */
00525 
00526 /*
00527 ZEXTERN int ZEXPORT deflateInit2 OF((z_streamp strm,
00528                                      int  level,
00529                                      int  method,
00530                                      int  windowBits,
00531                                      int  memLevel,
00532                                      int  strategy));
00533 
00534      This is another version of deflateInit with more compression options.  The
00535    fields next_in, zalloc, zfree and opaque must be initialized before by the
00536    caller.
00537 
00538      The method parameter is the compression method.  It must be Z_DEFLATED in
00539    this version of the library.
00540 
00541      The windowBits parameter is the base two logarithm of the window size
00542    (the size of the history buffer).  It should be in the range 8..15 for this
00543    version of the library.  Larger values of this parameter result in better
00544    compression at the expense of memory usage.  The default value is 15 if
00545    deflateInit is used instead.
00546 
00547      windowBits can also be -8..-15 for raw deflate.  In this case, -windowBits
00548    determines the window size.  deflate() will then generate raw deflate data
00549    with no zlib header or trailer, and will not compute an adler32 check value.
00550 
00551      windowBits can also be greater than 15 for optional gzip encoding.  Add
00552    16 to windowBits to write a simple gzip header and trailer around the
00553    compressed data instead of a zlib wrapper.  The gzip header will have no
00554    file name, no extra data, no comment, no modification time (set to zero), no
00555    header crc, and the operating system will be set to 255 (unknown).  If a
00556    gzip stream is being written, strm->adler is a crc32 instead of an adler32.
00557 
00558      The memLevel parameter specifies how much memory should be allocated
00559    for the internal compression state.  memLevel=1 uses minimum memory but is
00560    slow and reduces compression ratio; memLevel=9 uses maximum memory for
00561    optimal speed.  The default value is 8.  See zconf.h for total memory usage
00562    as a function of windowBits and memLevel.
00563 
00564      The strategy parameter is used to tune the compression algorithm.  Use the
00565    value Z_DEFAULT_STRATEGY for normal data, Z_FILTERED for data produced by a
00566    filter (or predictor), Z_HUFFMAN_ONLY to force Huffman encoding only (no
00567    string match), or Z_RLE to limit match distances to one (run-length
00568    encoding).  Filtered data consists mostly of small values with a somewhat
00569    random distribution.  In this case, the compression algorithm is tuned to
00570    compress them better.  The effect of Z_FILTERED is to force more Huffman
00571    coding and less string matching; it is somewhat intermediate between
00572    Z_DEFAULT_STRATEGY and Z_HUFFMAN_ONLY.  Z_RLE is designed to be almost as
00573    fast as Z_HUFFMAN_ONLY, but give better compression for PNG image data.  The
00574    strategy parameter only affects the compression ratio but not the
00575    correctness of the compressed output even if it is not set appropriately.
00576    Z_FIXED prevents the use of dynamic Huffman codes, allowing for a simpler
00577    decoder for special applications.
00578 
00579      deflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
00580    memory, Z_STREAM_ERROR if any parameter is invalid (such as an invalid
00581    method), or Z_VERSION_ERROR if the zlib library version (zlib_version) is
00582    incompatible with the version assumed by the caller (ZLIB_VERSION).  msg is
00583    set to null if there is no error message.  deflateInit2 does not perform any
00584    compression: this will be done by deflate().
00585 */
00586 
00587 ZEXTERN int ZEXPORT deflateSetDictionary OF((z_streamp strm,
00588                                              const Bytef *dictionary,
00589                                              uInt  dictLength));
00590 /*
00591      Initializes the compression dictionary from the given byte sequence
00592    without producing any compressed output.  When using the zlib format, this
00593    function must be called immediately after deflateInit, deflateInit2 or
00594    deflateReset, and before any call of deflate.  When doing raw deflate, this
00595    function must be called either before any call of deflate, or immediately
00596    after the completion of a deflate block, i.e. after all input has been
00597    consumed and all output has been delivered when using any of the flush
00598    options Z_BLOCK, Z_PARTIAL_FLUSH, Z_SYNC_FLUSH, or Z_FULL_FLUSH.  The
00599    compressor and decompressor must use exactly the same dictionary (see
00600    inflateSetDictionary).
00601 
00602      The dictionary should consist of strings (byte sequences) that are likely
00603    to be encountered later in the data to be compressed, with the most commonly
00604    used strings preferably put towards the end of the dictionary.  Using a
00605    dictionary is most useful when the data to be compressed is short and can be
00606    predicted with good accuracy; the data can then be compressed better than
00607    with the default empty dictionary.
00608 
00609      Depending on the size of the compression data structures selected by
00610    deflateInit or deflateInit2, a part of the dictionary may in effect be
00611    discarded, for example if the dictionary is larger than the window size
00612    provided in deflateInit or deflateInit2.  Thus the strings most likely to be
00613    useful should be put at the end of the dictionary, not at the front.  In
00614    addition, the current implementation of deflate will use at most the window
00615    size minus 262 bytes of the provided dictionary.
00616 
00617      Upon return of this function, strm->adler is set to the adler32 value
00618    of the dictionary; the decompressor may later use this value to determine
00619    which dictionary has been used by the compressor.  (The adler32 value
00620    applies to the whole dictionary even if only a subset of the dictionary is
00621    actually used by the compressor.) If a raw deflate was requested, then the
00622    adler32 value is not computed and strm->adler is not set.
00623 
00624      deflateSetDictionary returns Z_OK if success, or Z_STREAM_ERROR if a
00625    parameter is invalid (e.g.  dictionary being Z_NULL) or the stream state is
00626    inconsistent (for example if deflate has already been called for this stream
00627    or if not at a block boundary for raw deflate).  deflateSetDictionary does
00628    not perform any compression: this will be done by deflate().
00629 */
00630 
00631 ZEXTERN int ZEXPORT deflateCopy OF((z_streamp dest,
00632                                     z_streamp source));
00633 /*
00634      Sets the destination stream as a complete copy of the source stream.
00635 
00636      This function can be useful when several compression strategies will be
00637    tried, for example when there are several ways of pre-processing the input
00638    data with a filter.  The streams that will be discarded should then be freed
00639    by calling deflateEnd.  Note that deflateCopy duplicates the internal
00640    compression state which can be quite large, so this strategy is slow and can
00641    consume lots of memory.
00642 
00643      deflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
00644    enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
00645    (such as zalloc being Z_NULL).  msg is left unchanged in both source and
00646    destination.
00647 */
00648 
00649 ZEXTERN int ZEXPORT deflateReset OF((z_streamp strm));
00650 /*
00651      This function is equivalent to deflateEnd followed by deflateInit,
00652    but does not free and reallocate all the internal compression state.  The
00653    stream will keep the same compression level and any other attributes that
00654    may have been set by deflateInit2.
00655 
00656      deflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
00657    stream state was inconsistent (such as zalloc or state being Z_NULL).
00658 */
00659 
00660 ZEXTERN int ZEXPORT deflateParams OF((z_streamp strm,
00661                                       int level,
00662                                       int strategy));
00663 /*
00664      Dynamically update the compression level and compression strategy.  The
00665    interpretation of level and strategy is as in deflateInit2.  This can be
00666    used to switch between compression and straight copy of the input data, or
00667    to switch to a different kind of input data requiring a different strategy.
00668    If the compression level is changed, the input available so far is
00669    compressed with the old level (and may be flushed); the new level will take
00670    effect only at the next call of deflate().
00671 
00672      Before the call of deflateParams, the stream state must be set as for
00673    a call of deflate(), since the currently available input may have to be
00674    compressed and flushed.  In particular, strm->avail_out must be non-zero.
00675 
00676      deflateParams returns Z_OK if success, Z_STREAM_ERROR if the source
00677    stream state was inconsistent or if a parameter was invalid, Z_BUF_ERROR if
00678    strm->avail_out was zero.
00679 */
00680 
00681 ZEXTERN int ZEXPORT deflateTune OF((z_streamp strm,
00682                                     int good_length,
00683                                     int max_lazy,
00684                                     int nice_length,
00685                                     int max_chain));
00686 /*
00687      Fine tune deflate's internal compression parameters.  This should only be
00688    used by someone who understands the algorithm used by zlib's deflate for
00689    searching for the best matching string, and even then only by the most
00690    fanatic optimizer trying to squeeze out the last compressed bit for their
00691    specific input data.  Read the deflate.c source code for the meaning of the
00692    max_lazy, good_length, nice_length, and max_chain parameters.
00693 
00694      deflateTune() can be called after deflateInit() or deflateInit2(), and
00695    returns Z_OK on success, or Z_STREAM_ERROR for an invalid deflate stream.
00696  */
00697 
00698 ZEXTERN uLong ZEXPORT deflateBound OF((z_streamp strm,
00699                                        uLong sourceLen));
00700 /*
00701      deflateBound() returns an upper bound on the compressed size after
00702    deflation of sourceLen bytes.  It must be called after deflateInit() or
00703    deflateInit2(), and after deflateSetHeader(), if used.  This would be used
00704    to allocate an output buffer for deflation in a single pass, and so would be
00705    called before deflate().  If that first deflate() call is provided the
00706    sourceLen input bytes, an output buffer allocated to the size returned by
00707    deflateBound(), and the flush value Z_FINISH, then deflate() is guaranteed
00708    to return Z_STREAM_END.  Note that it is possible for the compressed size to
00709    be larger than the value returned by deflateBound() if flush options other
00710    than Z_FINISH or Z_NO_FLUSH are used.
00711 */
00712 
00713 ZEXTERN int ZEXPORT deflatePending OF((z_streamp strm,
00714                                        unsigned *pending,
00715                                        int *bits));
00716 /*
00717      deflatePending() returns the number of bytes and bits of output that have
00718    been generated, but not yet provided in the available output.  The bytes not
00719    provided would be due to the available output space having being consumed.
00720    The number of bits of output not provided are between 0 and 7, where they
00721    await more bits to join them in order to fill out a full byte.  If pending
00722    or bits are Z_NULL, then those values are not set.
00723 
00724      deflatePending returns Z_OK if success, or Z_STREAM_ERROR if the source
00725    stream state was inconsistent.
00726  */
00727 
00728 ZEXTERN int ZEXPORT deflatePrime OF((z_streamp strm,
00729                                      int bits,
00730                                      int value));
00731 /*
00732      deflatePrime() inserts bits in the deflate output stream.  The intent
00733    is that this function is used to start off the deflate output with the bits
00734    leftover from a previous deflate stream when appending to it.  As such, this
00735    function can only be used for raw deflate, and must be used before the first
00736    deflate() call after a deflateInit2() or deflateReset().  bits must be less
00737    than or equal to 16, and that many of the least significant bits of value
00738    will be inserted in the output.
00739 
00740      deflatePrime returns Z_OK if success, Z_BUF_ERROR if there was not enough
00741    room in the internal buffer to insert the bits, or Z_STREAM_ERROR if the
00742    source stream state was inconsistent.
00743 */
00744 
00745 ZEXTERN int ZEXPORT deflateSetHeader OF((z_streamp strm,
00746                                          gz_headerp head));
00747 /*
00748      deflateSetHeader() provides gzip header information for when a gzip
00749    stream is requested by deflateInit2().  deflateSetHeader() may be called
00750    after deflateInit2() or deflateReset() and before the first call of
00751    deflate().  The text, time, os, extra field, name, and comment information
00752    in the provided gz_header structure are written to the gzip header (xflag is
00753    ignored -- the extra flags are set according to the compression level).  The
00754    caller must assure that, if not Z_NULL, name and comment are terminated with
00755    a zero byte, and that if extra is not Z_NULL, that extra_len bytes are
00756    available there.  If hcrc is true, a gzip header crc is included.  Note that
00757    the current versions of the command-line version of gzip (up through version
00758    1.3.x) do not support header crc's, and will report that it is a "multi-part
00759    gzip file" and give up.
00760 
00761      If deflateSetHeader is not used, the default gzip header has text false,
00762    the time set to zero, and os set to 255, with no extra, name, or comment
00763    fields.  The gzip header is returned to the default state by deflateReset().
00764 
00765      deflateSetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
00766    stream state was inconsistent.
00767 */
00768 
00769 /*
00770 ZEXTERN int ZEXPORT inflateInit2 OF((z_streamp strm,
00771                                      int  windowBits));
00772 
00773      This is another version of inflateInit with an extra parameter.  The
00774    fields next_in, avail_in, zalloc, zfree and opaque must be initialized
00775    before by the caller.
00776 
00777      The windowBits parameter is the base two logarithm of the maximum window
00778    size (the size of the history buffer).  It should be in the range 8..15 for
00779    this version of the library.  The default value is 15 if inflateInit is used
00780    instead.  windowBits must be greater than or equal to the windowBits value
00781    provided to deflateInit2() while compressing, or it must be equal to 15 if
00782    deflateInit2() was not used.  If a compressed stream with a larger window
00783    size is given as input, inflate() will return with the error code
00784    Z_DATA_ERROR instead of trying to allocate a larger window.
00785 
00786      windowBits can also be zero to request that inflate use the window size in
00787    the zlib header of the compressed stream.
00788 
00789      windowBits can also be -8..-15 for raw inflate.  In this case, -windowBits
00790    determines the window size.  inflate() will then process raw deflate data,
00791    not looking for a zlib or gzip header, not generating a check value, and not
00792    looking for any check values for comparison at the end of the stream.  This
00793    is for use with other formats that use the deflate compressed data format
00794    such as zip.  Those formats provide their own check values.  If a custom
00795    format is developed using the raw deflate format for compressed data, it is
00796    recommended that a check value such as an adler32 or a crc32 be applied to
00797    the uncompressed data as is done in the zlib, gzip, and zip formats.  For
00798    most applications, the zlib format should be used as is.  Note that comments
00799    above on the use in deflateInit2() applies to the magnitude of windowBits.
00800 
00801      windowBits can also be greater than 15 for optional gzip decoding.  Add
00802    32 to windowBits to enable zlib and gzip decoding with automatic header
00803    detection, or add 16 to decode only the gzip format (the zlib format will
00804    return a Z_DATA_ERROR).  If a gzip stream is being decoded, strm->adler is a
00805    crc32 instead of an adler32.
00806 
00807      inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
00808    memory, Z_VERSION_ERROR if the zlib library version is incompatible with the
00809    version assumed by the caller, or Z_STREAM_ERROR if the parameters are
00810    invalid, such as a null pointer to the structure.  msg is set to null if
00811    there is no error message.  inflateInit2 does not perform any decompression
00812    apart from possibly reading the zlib header if present: actual decompression
00813    will be done by inflate().  (So next_in and avail_in may be modified, but
00814    next_out and avail_out are unused and unchanged.) The current implementation
00815    of inflateInit2() does not process any header information -- that is
00816    deferred until inflate() is called.
00817 */
00818 
00819 ZEXTERN int ZEXPORT inflateSetDictionary OF((z_streamp strm,
00820                                              const Bytef *dictionary,
00821                                              uInt  dictLength));
00822 /*
00823      Initializes the decompression dictionary from the given uncompressed byte
00824    sequence.  This function must be called immediately after a call of inflate,
00825    if that call returned Z_NEED_DICT.  The dictionary chosen by the compressor
00826    can be determined from the adler32 value returned by that call of inflate.
00827    The compressor and decompressor must use exactly the same dictionary (see
00828    deflateSetDictionary).  For raw inflate, this function can be called at any
00829    time to set the dictionary.  If the provided dictionary is smaller than the
00830    window and there is already data in the window, then the provided dictionary
00831    will amend what's there.  The application must insure that the dictionary
00832    that was used for compression is provided.
00833 
00834      inflateSetDictionary returns Z_OK if success, Z_STREAM_ERROR if a
00835    parameter is invalid (e.g.  dictionary being Z_NULL) or the stream state is
00836    inconsistent, Z_DATA_ERROR if the given dictionary doesn't match the
00837    expected one (incorrect adler32 value).  inflateSetDictionary does not
00838    perform any decompression: this will be done by subsequent calls of
00839    inflate().
00840 */
00841 
00842 ZEXTERN int ZEXPORT inflateGetDictionary OF((z_streamp strm,
00843                                              Bytef *dictionary,
00844                                              uInt  *dictLength));
00845 /*
00846      Returns the sliding dictionary being maintained by inflate.  dictLength is
00847    set to the number of bytes in the dictionary, and that many bytes are copied
00848    to dictionary.  dictionary must have enough space, where 32768 bytes is
00849    always enough.  If inflateGetDictionary() is called with dictionary equal to
00850    Z_NULL, then only the dictionary length is returned, and nothing is copied.
00851    Similary, if dictLength is Z_NULL, then it is not set.
00852 
00853      inflateGetDictionary returns Z_OK on success, or Z_STREAM_ERROR if the
00854    stream state is inconsistent.
00855 */
00856 
00857 ZEXTERN int ZEXPORT inflateSync OF((z_streamp strm));
00858 /*
00859      Skips invalid compressed data until a possible full flush point (see above
00860    for the description of deflate with Z_FULL_FLUSH) can be found, or until all
00861    available input is skipped.  No output is provided.
00862 
00863      inflateSync searches for a 00 00 FF FF pattern in the compressed data.
00864    All full flush points have this pattern, but not all occurrences of this
00865    pattern are full flush points.
00866 
00867      inflateSync returns Z_OK if a possible full flush point has been found,
00868    Z_BUF_ERROR if no more input was provided, Z_DATA_ERROR if no flush point
00869    has been found, or Z_STREAM_ERROR if the stream structure was inconsistent.
00870    In the success case, the application may save the current current value of
00871    total_in which indicates where valid compressed data was found.  In the
00872    error case, the application may repeatedly call inflateSync, providing more
00873    input each time, until success or end of the input data.
00874 */
00875 
00876 ZEXTERN int ZEXPORT inflateCopy OF((z_streamp dest,
00877                                     z_streamp source));
00878 /*
00879      Sets the destination stream as a complete copy of the source stream.
00880 
00881      This function can be useful when randomly accessing a large stream.  The
00882    first pass through the stream can periodically record the inflate state,
00883    allowing restarting inflate at those points when randomly accessing the
00884    stream.
00885 
00886      inflateCopy returns Z_OK if success, Z_MEM_ERROR if there was not
00887    enough memory, Z_STREAM_ERROR if the source stream state was inconsistent
00888    (such as zalloc being Z_NULL).  msg is left unchanged in both source and
00889    destination.
00890 */
00891 
00892 ZEXTERN int ZEXPORT inflateReset OF((z_streamp strm));
00893 /*
00894      This function is equivalent to inflateEnd followed by inflateInit,
00895    but does not free and reallocate all the internal decompression state.  The
00896    stream will keep attributes that may have been set by inflateInit2.
00897 
00898      inflateReset returns Z_OK if success, or Z_STREAM_ERROR if the source
00899    stream state was inconsistent (such as zalloc or state being Z_NULL).
00900 */
00901 
00902 ZEXTERN int ZEXPORT inflateReset2 OF((z_streamp strm,
00903                                       int windowBits));
00904 /*
00905      This function is the same as inflateReset, but it also permits changing
00906    the wrap and window size requests.  The windowBits parameter is interpreted
00907    the same as it is for inflateInit2.
00908 
00909      inflateReset2 returns Z_OK if success, or Z_STREAM_ERROR if the source
00910    stream state was inconsistent (such as zalloc or state being Z_NULL), or if
00911    the windowBits parameter is invalid.
00912 */
00913 
00914 ZEXTERN int ZEXPORT inflatePrime OF((z_streamp strm,
00915                                      int bits,
00916                                      int value));
00917 /*
00918      This function inserts bits in the inflate input stream.  The intent is
00919    that this function is used to start inflating at a bit position in the
00920    middle of a byte.  The provided bits will be used before any bytes are used
00921    from next_in.  This function should only be used with raw inflate, and
00922    should be used before the first inflate() call after inflateInit2() or
00923    inflateReset().  bits must be less than or equal to 16, and that many of the
00924    least significant bits of value will be inserted in the input.
00925 
00926      If bits is negative, then the input stream bit buffer is emptied.  Then
00927    inflatePrime() can be called again to put bits in the buffer.  This is used
00928    to clear out bits leftover after feeding inflate a block description prior
00929    to feeding inflate codes.
00930 
00931      inflatePrime returns Z_OK if success, or Z_STREAM_ERROR if the source
00932    stream state was inconsistent.
00933 */
00934 
00935 ZEXTERN long ZEXPORT inflateMark OF((z_streamp strm));
00936 /*
00937      This function returns two values, one in the lower 16 bits of the return
00938    value, and the other in the remaining upper bits, obtained by shifting the
00939    return value down 16 bits.  If the upper value is -1 and the lower value is
00940    zero, then inflate() is currently decoding information outside of a block.
00941    If the upper value is -1 and the lower value is non-zero, then inflate is in
00942    the middle of a stored block, with the lower value equaling the number of
00943    bytes from the input remaining to copy.  If the upper value is not -1, then
00944    it is the number of bits back from the current bit position in the input of
00945    the code (literal or length/distance pair) currently being processed.  In
00946    that case the lower value is the number of bytes already emitted for that
00947    code.
00948 
00949      A code is being processed if inflate is waiting for more input to complete
00950    decoding of the code, or if it has completed decoding but is waiting for
00951    more output space to write the literal or match data.
00952 
00953      inflateMark() is used to mark locations in the input data for random
00954    access, which may be at bit positions, and to note those cases where the
00955    output of a code may span boundaries of random access blocks.  The current
00956    location in the input stream can be determined from avail_in and data_type
00957    as noted in the description for the Z_BLOCK flush parameter for inflate.
00958 
00959      inflateMark returns the value noted above or -1 << 16 if the provided
00960    source stream state was inconsistent.
00961 */
00962 
00963 ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm,
00964                                          gz_headerp head));
00965 /*
00966      inflateGetHeader() requests that gzip header information be stored in the
00967    provided gz_header structure.  inflateGetHeader() may be called after
00968    inflateInit2() or inflateReset(), and before the first call of inflate().
00969    As inflate() processes the gzip stream, head->done is zero until the header
00970    is completed, at which time head->done is set to one.  If a zlib stream is
00971    being decoded, then head->done is set to -1 to indicate that there will be
00972    no gzip header information forthcoming.  Note that Z_BLOCK or Z_TREES can be
00973    used to force inflate() to return immediately after header processing is
00974    complete and before any actual data is decompressed.
00975 
00976      The text, time, xflags, and os fields are filled in with the gzip header
00977    contents.  hcrc is set to true if there is a header CRC.  (The header CRC
00978    was valid if done is set to one.) If extra is not Z_NULL, then extra_max
00979    contains the maximum number of bytes to write to extra.  Once done is true,
00980    extra_len contains the actual extra field length, and extra contains the
00981    extra field, or that field truncated if extra_max is less than extra_len.
00982    If name is not Z_NULL, then up to name_max characters are written there,
00983    terminated with a zero unless the length is greater than name_max.  If
00984    comment is not Z_NULL, then up to comm_max characters are written there,
00985    terminated with a zero unless the length is greater than comm_max.  When any
00986    of extra, name, or comment are not Z_NULL and the respective field is not
00987    present in the header, then that field is set to Z_NULL to signal its
00988    absence.  This allows the use of deflateSetHeader() with the returned
00989    structure to duplicate the header.  However if those fields are set to
00990    allocated memory, then the application will need to save those pointers
00991    elsewhere so that they can be eventually freed.
00992 
00993      If inflateGetHeader is not used, then the header information is simply
00994    discarded.  The header is always checked for validity, including the header
00995    CRC if present.  inflateReset() will reset the process to discard the header
00996    information.  The application would need to call inflateGetHeader() again to
00997    retrieve the header from the next gzip stream.
00998 
00999      inflateGetHeader returns Z_OK if success, or Z_STREAM_ERROR if the source
01000    stream state was inconsistent.
01001 */
01002 
01003 /*
01004 ZEXTERN int ZEXPORT inflateBackInit OF((z_streamp strm, int windowBits,
01005                                         unsigned char FAR *window));
01006 
01007      Initialize the internal stream state for decompression using inflateBack()
01008    calls.  The fields zalloc, zfree and opaque in strm must be initialized
01009    before the call.  If zalloc and zfree are Z_NULL, then the default library-
01010    derived memory allocation routines are used.  windowBits is the base two
01011    logarithm of the window size, in the range 8..15.  window is a caller
01012    supplied buffer of that size.  Except for special applications where it is
01013    assured that deflate was used with small window sizes, windowBits must be 15
01014    and a 32K byte window must be supplied to be able to decompress general
01015    deflate streams.
01016 
01017      See inflateBack() for the usage of these routines.
01018 
01019      inflateBackInit will return Z_OK on success, Z_STREAM_ERROR if any of
01020    the parameters are invalid, Z_MEM_ERROR if the internal state could not be
01021    allocated, or Z_VERSION_ERROR if the version of the library does not match
01022    the version of the header file.
01023 */
01024 
01025 typedef unsigned (*in_func) OF((void FAR *,
01026                                 z_const unsigned char FAR * FAR *));
01027 typedef int (*out_func) OF((void FAR *, unsigned char FAR *, unsigned));
01028 
01029 ZEXTERN int ZEXPORT inflateBack OF((z_streamp strm,
01030                                     in_func in, void FAR *in_desc,
01031                                     out_func out, void FAR *out_desc));
01032 /*
01033      inflateBack() does a raw inflate with a single call using a call-back
01034    interface for input and output.  This is potentially more efficient than
01035    inflate() for file i/o applications, in that it avoids copying between the
01036    output and the sliding window by simply making the window itself the output
01037    buffer.  inflate() can be faster on modern CPUs when used with large
01038    buffers.  inflateBack() trusts the application to not change the output
01039    buffer passed by the output function, at least until inflateBack() returns.
01040 
01041      inflateBackInit() must be called first to allocate the internal state
01042    and to initialize the state with the user-provided window buffer.
01043    inflateBack() may then be used multiple times to inflate a complete, raw
01044    deflate stream with each call.  inflateBackEnd() is then called to free the
01045    allocated state.
01046 
01047      A raw deflate stream is one with no zlib or gzip header or trailer.
01048    This routine would normally be used in a utility that reads zip or gzip
01049    files and writes out uncompressed files.  The utility would decode the
01050    header and process the trailer on its own, hence this routine expects only
01051    the raw deflate stream to decompress.  This is different from the normal
01052    behavior of inflate(), which expects either a zlib or gzip header and
01053    trailer around the deflate stream.
01054 
01055      inflateBack() uses two subroutines supplied by the caller that are then
01056    called by inflateBack() for input and output.  inflateBack() calls those
01057    routines until it reads a complete deflate stream and writes out all of the
01058    uncompressed data, or until it encounters an error.  The function's
01059    parameters and return types are defined above in the in_func and out_func
01060    typedefs.  inflateBack() will call in(in_desc, &buf) which should return the
01061    number of bytes of provided input, and a pointer to that input in buf.  If
01062    there is no input available, in() must return zero--buf is ignored in that
01063    case--and inflateBack() will return a buffer error.  inflateBack() will call
01064    out(out_desc, buf, len) to write the uncompressed data buf[0..len-1].  out()
01065    should return zero on success, or non-zero on failure.  If out() returns
01066    non-zero, inflateBack() will return with an error.  Neither in() nor out()
01067    are permitted to change the contents of the window provided to
01068    inflateBackInit(), which is also the buffer that out() uses to write from.
01069    The length written by out() will be at most the window size.  Any non-zero
01070    amount of input may be provided by in().
01071 
01072      For convenience, inflateBack() can be provided input on the first call by
01073    setting strm->next_in and strm->avail_in.  If that input is exhausted, then
01074    in() will be called.  Therefore strm->next_in must be initialized before
01075    calling inflateBack().  If strm->next_in is Z_NULL, then in() will be called
01076    immediately for input.  If strm->next_in is not Z_NULL, then strm->avail_in
01077    must also be initialized, and then if strm->avail_in is not zero, input will
01078    initially be taken from strm->next_in[0 ..  strm->avail_in - 1].
01079 
01080      The in_desc and out_desc parameters of inflateBack() is passed as the
01081    first parameter of in() and out() respectively when they are called.  These
01082    descriptors can be optionally used to pass any information that the caller-
01083    supplied in() and out() functions need to do their job.
01084 
01085      On return, inflateBack() will set strm->next_in and strm->avail_in to
01086    pass back any unused input that was provided by the last in() call.  The
01087    return values of inflateBack() can be Z_STREAM_END on success, Z_BUF_ERROR
01088    if in() or out() returned an error, Z_DATA_ERROR if there was a format error
01089    in the deflate stream (in which case strm->msg is set to indicate the nature
01090    of the error), or Z_STREAM_ERROR if the stream was not properly initialized.
01091    In the case of Z_BUF_ERROR, an input or output error can be distinguished
01092    using strm->next_in which will be Z_NULL only if in() returned an error.  If
01093    strm->next_in is not Z_NULL, then the Z_BUF_ERROR was due to out() returning
01094    non-zero.  (in() will always be called before out(), so strm->next_in is
01095    assured to be defined if out() returns non-zero.) Note that inflateBack()
01096    cannot return Z_OK.
01097 */
01098 
01099 ZEXTERN int ZEXPORT inflateBackEnd OF((z_streamp strm));
01100 /*
01101      All memory allocated by inflateBackInit() is freed.
01102 
01103      inflateBackEnd() returns Z_OK on success, or Z_STREAM_ERROR if the stream
01104    state was inconsistent.
01105 */
01106 
01107 ZEXTERN uLong ZEXPORT zlibCompileFlags OF((void));
01108 /* Return flags indicating compile-time options.
01109 
01110     Type sizes, two bits each, 00 = 16 bits, 01 = 32, 10 = 64, 11 = other:
01111      1.0: size of uInt
01112      3.2: size of uLong
01113      5.4: size of voidpf (pointer)
01114      7.6: size of z_off_t
01115 
01116     Compiler, assembler, and debug options:
01117      8: DEBUG
01118      9: ASMV or ASMINF -- use ASM code
01119      10: ZLIB_WINAPI -- exported functions use the WINAPI calling convention
01120      11: 0 (reserved)
01121 
01122     One-time table building (smaller code, but not thread-safe if true):
01123      12: BUILDFIXED -- build static block decoding tables when needed
01124      13: DYNAMIC_CRC_TABLE -- build CRC calculation tables when needed
01125      14,15: 0 (reserved)
01126 
01127     Library content (indicates missing functionality):
01128      16: NO_GZCOMPRESS -- gz* functions cannot compress (to avoid linking
01129                           deflate code when not needed)
01130      17: NO_GZIP -- deflate can't write gzip streams, and inflate can't detect
01131                     and decode gzip streams (to avoid linking crc code)
01132      18-19: 0 (reserved)
01133 
01134     Operation variations (changes in library functionality):
01135      20: PKZIP_BUG_WORKAROUND -- slightly more permissive inflate
01136      21: FASTEST -- deflate algorithm with only one, lowest compression level
01137      22,23: 0 (reserved)
01138 
01139     The sprintf variant used by gzprintf (zero is best):
01140      24: 0 = vs*, 1 = s* -- 1 means limited to 20 arguments after the format
01141      25: 0 = *nprintf, 1 = *printf -- 1 means gzprintf() not secure!
01142      26: 0 = returns value, 1 = void -- 1 means inferred string length returned
01143 
01144     Remainder:
01145      27-31: 0 (reserved)
01146  */
01147 
01148 #ifndef Z_SOLO
01149 
01150                         /* utility functions */
01151 
01152 /*
01153      The following utility functions are implemented on top of the basic
01154    stream-oriented functions.  To simplify the interface, some default options
01155    are assumed (compression level and memory usage, standard memory allocation
01156    functions).  The source code of these utility functions can be modified if
01157    you need special options.
01158 */
01159 
01160 ZEXTERN int ZEXPORT compress OF((Bytef *dest,   uLongf *destLen,
01161                                  const Bytef *source, uLong sourceLen));
01162 /*
01163      Compresses the source buffer into the destination buffer.  sourceLen is
01164    the byte length of the source buffer.  Upon entry, destLen is the total size
01165    of the destination buffer, which must be at least the value returned by
01166    compressBound(sourceLen).  Upon exit, destLen is the actual size of the
01167    compressed buffer.
01168 
01169      compress returns Z_OK if success, Z_MEM_ERROR if there was not
01170    enough memory, Z_BUF_ERROR if there was not enough room in the output
01171    buffer.
01172 */
01173 
01174 ZEXTERN int ZEXPORT compress2 OF((Bytef *dest,   uLongf *destLen,
01175                                   const Bytef *source, uLong sourceLen,
01176                                   int level));
01177 /*
01178      Compresses the source buffer into the destination buffer.  The level
01179    parameter has the same meaning as in deflateInit.  sourceLen is the byte
01180    length of the source buffer.  Upon entry, destLen is the total size of the
01181    destination buffer, which must be at least the value returned by
01182    compressBound(sourceLen).  Upon exit, destLen is the actual size of the
01183    compressed buffer.
01184 
01185      compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
01186    memory, Z_BUF_ERROR if there was not enough room in the output buffer,
01187    Z_STREAM_ERROR if the level parameter is invalid.
01188 */
01189 
01190 ZEXTERN uLong ZEXPORT compressBound OF((uLong sourceLen));
01191 /*
01192      compressBound() returns an upper bound on the compressed size after
01193    compress() or compress2() on sourceLen bytes.  It would be used before a
01194    compress() or compress2() call to allocate the destination buffer.
01195 */
01196 
01197 ZEXTERN int ZEXPORT uncompress OF((Bytef *dest,   uLongf *destLen,
01198                                    const Bytef *source, uLong sourceLen));
01199 /*
01200      Decompresses the source buffer into the destination buffer.  sourceLen is
01201    the byte length of the source buffer.  Upon entry, destLen is the total size
01202    of the destination buffer, which must be large enough to hold the entire
01203    uncompressed data.  (The size of the uncompressed data must have been saved
01204    previously by the compressor and transmitted to the decompressor by some
01205    mechanism outside the scope of this compression library.) Upon exit, destLen
01206    is the actual size of the uncompressed buffer.
01207 
01208      uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
01209    enough memory, Z_BUF_ERROR if there was not enough room in the output
01210    buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete.  In
01211    the case where there is not enough room, uncompress() will fill the output
01212    buffer with the uncompressed data up to that point.
01213 */
01214 
01215                         /* gzip file access functions */
01216 
01217 /*
01218      This library supports reading and writing files in gzip (.gz) format with
01219    an interface similar to that of stdio, using the functions that start with
01220    "gz".  The gzip format is different from the zlib format.  gzip is a gzip
01221    wrapper, documented in RFC 1952, wrapped around a deflate stream.
01222 */
01223 
01224 typedef struct gzFile_s *gzFile;    /* semi-opaque gzip file descriptor */
01225 
01226 /*
01227 ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode));
01228 
01229      Opens a gzip (.gz) file for reading or writing.  The mode parameter is as
01230    in fopen ("rb" or "wb") but can also include a compression level ("wb9") or
01231    a strategy: 'f' for filtered data as in "wb6f", 'h' for Huffman-only
01232    compression as in "wb1h", 'R' for run-length encoding as in "wb1R", or 'F'
01233    for fixed code compression as in "wb9F".  (See the description of
01234    deflateInit2 for more information about the strategy parameter.)  'T' will
01235    request transparent writing or appending with no compression and not using
01236    the gzip format.
01237 
01238      "a" can be used instead of "w" to request that the gzip stream that will
01239    be written be appended to the file.  "+" will result in an error, since
01240    reading and writing to the same gzip file is not supported.  The addition of
01241    "x" when writing will create the file exclusively, which fails if the file
01242    already exists.  On systems that support it, the addition of "e" when
01243    reading or writing will set the flag to close the file on an execve() call.
01244 
01245      These functions, as well as gzip, will read and decode a sequence of gzip
01246    streams in a file.  The append function of gzopen() can be used to create
01247    such a file.  (Also see gzflush() for another way to do this.)  When
01248    appending, gzopen does not test whether the file begins with a gzip stream,
01249    nor does it look for the end of the gzip streams to begin appending.  gzopen
01250    will simply append a gzip stream to the existing file.
01251 
01252      gzopen can be used to read a file which is not in gzip format; in this
01253    case gzread will directly read from the file without decompression.  When
01254    reading, this will be detected automatically by looking for the magic two-
01255    byte gzip header.
01256 
01257      gzopen returns NULL if the file could not be opened, if there was
01258    insufficient memory to allocate the gzFile state, or if an invalid mode was
01259    specified (an 'r', 'w', or 'a' was not provided, or '+' was provided).
01260    errno can be checked to determine if the reason gzopen failed was that the
01261    file could not be opened.
01262 */
01263 
01264 ZEXTERN gzFile ZEXPORT gzdopen OF((int fd, const char *mode));
01265 /*
01266      gzdopen associates a gzFile with the file descriptor fd.  File descriptors
01267    are obtained from calls like open, dup, creat, pipe or fileno (if the file
01268    has been previously opened with fopen).  The mode parameter is as in gzopen.
01269 
01270      The next call of gzclose on the returned gzFile will also close the file
01271    descriptor fd, just like fclose(fdopen(fd, mode)) closes the file descriptor
01272    fd.  If you want to keep fd open, use fd = dup(fd_keep); gz = gzdopen(fd,
01273    mode);.  The duplicated descriptor should be saved to avoid a leak, since
01274    gzdopen does not close fd if it fails.  If you are using fileno() to get the
01275    file descriptor from a FILE *, then you will have to use dup() to avoid
01276    double-close()ing the file descriptor.  Both gzclose() and fclose() will
01277    close the associated file descriptor, so they need to have different file
01278    descriptors.
01279 
01280      gzdopen returns NULL if there was insufficient memory to allocate the
01281    gzFile state, if an invalid mode was specified (an 'r', 'w', or 'a' was not
01282    provided, or '+' was provided), or if fd is -1.  The file descriptor is not
01283    used until the next gz* read, write, seek, or close operation, so gzdopen
01284    will not detect if fd is invalid (unless fd is -1).
01285 */
01286 
01287 ZEXTERN int ZEXPORT gzbuffer OF((gzFile file, unsigned size));
01288 /*
01289      Set the internal buffer size used by this library's functions.  The
01290    default buffer size is 8192 bytes.  This function must be called after
01291    gzopen() or gzdopen(), and before any other calls that read or write the
01292    file.  The buffer memory allocation is always deferred to the first read or
01293    write.  Two buffers are allocated, either both of the specified size when
01294    writing, or one of the specified size and the other twice that size when
01295    reading.  A larger buffer size of, for example, 64K or 128K bytes will
01296    noticeably increase the speed of decompression (reading).
01297 
01298      The new buffer size also affects the maximum length for gzprintf().
01299 
01300      gzbuffer() returns 0 on success, or -1 on failure, such as being called
01301    too late.
01302 */
01303 
01304 ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy));
01305 /*
01306      Dynamically update the compression level or strategy.  See the description
01307    of deflateInit2 for the meaning of these parameters.
01308 
01309      gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not
01310    opened for writing.
01311 */
01312 
01313 ZEXTERN int ZEXPORT gzread OF((gzFile file, voidp buf, unsigned len));
01314 /*
01315      Reads the given number of uncompressed bytes from the compressed file.  If
01316    the input file is not in gzip format, gzread copies the given number of
01317    bytes into the buffer directly from the file.
01318 
01319      After reaching the end of a gzip stream in the input, gzread will continue
01320    to read, looking for another gzip stream.  Any number of gzip streams may be
01321    concatenated in the input file, and will all be decompressed by gzread().
01322    If something other than a gzip stream is encountered after a gzip stream,
01323    that remaining trailing garbage is ignored (and no error is returned).
01324 
01325      gzread can be used to read a gzip file that is being concurrently written.
01326    Upon reaching the end of the input, gzread will return with the available
01327    data.  If the error code returned by gzerror is Z_OK or Z_BUF_ERROR, then
01328    gzclearerr can be used to clear the end of file indicator in order to permit
01329    gzread to be tried again.  Z_OK indicates that a gzip stream was completed
01330    on the last gzread.  Z_BUF_ERROR indicates that the input file ended in the
01331    middle of a gzip stream.  Note that gzread does not return -1 in the event
01332    of an incomplete gzip stream.  This error is deferred until gzclose(), which
01333    will return Z_BUF_ERROR if the last gzread ended in the middle of a gzip
01334    stream.  Alternatively, gzerror can be used before gzclose to detect this
01335    case.
01336 
01337      gzread returns the number of uncompressed bytes actually read, less than
01338    len for end of file, or -1 for error.
01339 */
01340 
01341 ZEXTERN int ZEXPORT gzwrite OF((gzFile file,
01342                                 voidpc buf, unsigned len));
01343 /*
01344      Writes the given number of uncompressed bytes into the compressed file.
01345    gzwrite returns the number of uncompressed bytes written or 0 in case of
01346    error.
01347 */
01348 
01349 ZEXTERN int ZEXPORTVA gzprintf Z_ARG((gzFile file, const char *format, ...));
01350 /*
01351      Converts, formats, and writes the arguments to the compressed file under
01352    control of the format string, as in fprintf.  gzprintf returns the number of
01353    uncompressed bytes actually written, or 0 in case of error.  The number of
01354    uncompressed bytes written is limited to 8191, or one less than the buffer
01355    size given to gzbuffer().  The caller should assure that this limit is not
01356    exceeded.  If it is exceeded, then gzprintf() will return an error (0) with
01357    nothing written.  In this case, there may also be a buffer overflow with
01358    unpredictable consequences, which is possible only if zlib was compiled with
01359    the insecure functions sprintf() or vsprintf() because the secure snprintf()
01360    or vsnprintf() functions were not available.  This can be determined using
01361    zlibCompileFlags().
01362 */
01363 
01364 ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s));
01365 /*
01366      Writes the given null-terminated string to the compressed file, excluding
01367    the terminating null character.
01368 
01369      gzputs returns the number of characters written, or -1 in case of error.
01370 */
01371 
01372 ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len));
01373 /*
01374      Reads bytes from the compressed file until len-1 characters are read, or a
01375    newline character is read and transferred to buf, or an end-of-file
01376    condition is encountered.  If any characters are read or if len == 1, the
01377    string is terminated with a null character.  If no characters are read due
01378    to an end-of-file or len < 1, then the buffer is left untouched.
01379 
01380      gzgets returns buf which is a null-terminated string, or it returns NULL
01381    for end-of-file or in case of error.  If there was an error, the contents at
01382    buf are indeterminate.
01383 */
01384 
01385 ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c));
01386 /*
01387      Writes c, converted to an unsigned char, into the compressed file.  gzputc
01388    returns the value that was written, or -1 in case of error.
01389 */
01390 
01391 ZEXTERN int ZEXPORT gzgetc OF((gzFile file));
01392 /*
01393      Reads one byte from the compressed file.  gzgetc returns this byte or -1
01394    in case of end of file or error.  This is implemented as a macro for speed.
01395    As such, it does not do all of the checking the other functions do.  I.e.
01396    it does not check to see if file is NULL, nor whether the structure file
01397    points to has been clobbered or not.
01398 */
01399 
01400 ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file));
01401 /*
01402      Push one character back onto the stream to be read as the first character
01403    on the next read.  At least one character of push-back is allowed.
01404    gzungetc() returns the character pushed, or -1 on failure.  gzungetc() will
01405    fail if c is -1, and may fail if a character has been pushed but not read
01406    yet.  If gzungetc is used immediately after gzopen or gzdopen, at least the
01407    output buffer size of pushed characters is allowed.  (See gzbuffer above.)
01408    The pushed character will be discarded if the stream is repositioned with
01409    gzseek() or gzrewind().
01410 */
01411 
01412 ZEXTERN int ZEXPORT gzflush OF((gzFile file, int flush));
01413 /*
01414      Flushes all pending output into the compressed file.  The parameter flush
01415    is as in the deflate() function.  The return value is the zlib error number
01416    (see function gzerror below).  gzflush is only permitted when writing.
01417 
01418      If the flush parameter is Z_FINISH, the remaining data is written and the
01419    gzip stream is completed in the output.  If gzwrite() is called again, a new
01420    gzip stream will be started in the output.  gzread() is able to read such
01421    concatented gzip streams.
01422 
01423      gzflush should be called only when strictly necessary because it will
01424    degrade compression if called too often.
01425 */
01426 
01427 /*
01428 ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile file,
01429                                    z_off_t offset, int whence));
01430 
01431      Sets the starting position for the next gzread or gzwrite on the given
01432    compressed file.  The offset represents a number of bytes in the
01433    uncompressed data stream.  The whence parameter is defined as in lseek(2);
01434    the value SEEK_END is not supported.
01435 
01436      If the file is opened for reading, this function is emulated but can be
01437    extremely slow.  If the file is opened for writing, only forward seeks are
01438    supported; gzseek then compresses a sequence of zeroes up to the new
01439    starting position.
01440 
01441      gzseek returns the resulting offset location as measured in bytes from
01442    the beginning of the uncompressed stream, or -1 in case of error, in
01443    particular if the file is opened for writing and the new starting position
01444    would be before the current position.
01445 */
01446 
01447 ZEXTERN int ZEXPORT    gzrewind OF((gzFile file));
01448 /*
01449      Rewinds the given file. This function is supported only for reading.
01450 
01451      gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET)
01452 */
01453 
01454 /*
01455 ZEXTERN z_off_t ZEXPORT    gztell OF((gzFile file));
01456 
01457      Returns the starting position for the next gzread or gzwrite on the given
01458    compressed file.  This position represents a number of bytes in the
01459    uncompressed data stream, and is zero when starting, even if appending or
01460    reading a gzip stream from the middle of a file using gzdopen().
01461 
01462      gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)
01463 */
01464 
01465 /*
01466 ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile file));
01467 
01468      Returns the current offset in the file being read or written.  This offset
01469    includes the count of bytes that precede the gzip stream, for example when
01470    appending or when using gzdopen() for reading.  When reading, the offset
01471    does not include as yet unused buffered input.  This information can be used
01472    for a progress indicator.  On error, gzoffset() returns -1.
01473 */
01474 
01475 ZEXTERN int ZEXPORT gzeof OF((gzFile file));
01476 /*
01477      Returns true (1) if the end-of-file indicator has been set while reading,
01478    false (0) otherwise.  Note that the end-of-file indicator is set only if the
01479    read tried to go past the end of the input, but came up short.  Therefore,
01480    just like feof(), gzeof() may return false even if there is no more data to
01481    read, in the event that the last read request was for the exact number of
01482    bytes remaining in the input file.  This will happen if the input file size
01483    is an exact multiple of the buffer size.
01484 
01485      If gzeof() returns true, then the read functions will return no more data,
01486    unless the end-of-file indicator is reset by gzclearerr() and the input file
01487    has grown since the previous end of file was detected.
01488 */
01489 
01490 ZEXTERN int ZEXPORT gzdirect OF((gzFile file));
01491 /*
01492      Returns true (1) if file is being copied directly while reading, or false
01493    (0) if file is a gzip stream being decompressed.
01494 
01495      If the input file is empty, gzdirect() will return true, since the input
01496    does not contain a gzip stream.
01497 
01498      If gzdirect() is used immediately after gzopen() or gzdopen() it will
01499    cause buffers to be allocated to allow reading the file to determine if it
01500    is a gzip file.  Therefore if gzbuffer() is used, it should be called before
01501    gzdirect().
01502 
01503      When writing, gzdirect() returns true (1) if transparent writing was
01504    requested ("wT" for the gzopen() mode), or false (0) otherwise.  (Note:
01505    gzdirect() is not needed when writing.  Transparent writing must be
01506    explicitly requested, so the application already knows the answer.  When
01507    linking statically, using gzdirect() will include all of the zlib code for
01508    gzip file reading and decompression, which may not be desired.)
01509 */
01510 
01511 ZEXTERN int ZEXPORT    gzclose OF((gzFile file));
01512 /*
01513      Flushes all pending output if necessary, closes the compressed file and
01514    deallocates the (de)compression state.  Note that once file is closed, you
01515    cannot call gzerror with file, since its structures have been deallocated.
01516    gzclose must not be called more than once on the same file, just as free
01517    must not be called more than once on the same allocation.
01518 
01519      gzclose will return Z_STREAM_ERROR if file is not valid, Z_ERRNO on a
01520    file operation error, Z_MEM_ERROR if out of memory, Z_BUF_ERROR if the
01521    last read ended in the middle of a gzip stream, or Z_OK on success.
01522 */
01523 
01524 ZEXTERN int ZEXPORT gzclose_r OF((gzFile file));
01525 ZEXTERN int ZEXPORT gzclose_w OF((gzFile file));
01526 /*
01527      Same as gzclose(), but gzclose_r() is only for use when reading, and
01528    gzclose_w() is only for use when writing or appending.  The advantage to
01529    using these instead of gzclose() is that they avoid linking in zlib
01530    compression or decompression code that is not used when only reading or only
01531    writing respectively.  If gzclose() is used, then both compression and
01532    decompression code will be included the application when linking to a static
01533    zlib library.
01534 */
01535 
01536 ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum));
01537 /*
01538      Returns the error message for the last error which occurred on the given
01539    compressed file.  errnum is set to zlib error number.  If an error occurred
01540    in the file system and not in the compression library, errnum is set to
01541    Z_ERRNO and the application may consult errno to get the exact error code.
01542 
01543      The application must not modify the returned string.  Future calls to
01544    this function may invalidate the previously returned string.  If file is
01545    closed, then the string previously returned by gzerror will no longer be
01546    available.
01547 
01548      gzerror() should be used to distinguish errors from end-of-file for those
01549    functions above that do not distinguish those cases in their return values.
01550 */
01551 
01552 ZEXTERN void ZEXPORT gzclearerr OF((gzFile file));
01553 /*
01554      Clears the error and end-of-file flags for file.  This is analogous to the
01555    clearerr() function in stdio.  This is useful for continuing to read a gzip
01556    file that is being written concurrently.
01557 */
01558 
01559 #endif /* !Z_SOLO */
01560 
01561                         /* checksum functions */
01562 
01563 /*
01564      These functions are not related to compression but are exported
01565    anyway because they might be useful in applications using the compression
01566    library.
01567 */
01568 
01569 ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len));
01570 /*
01571      Update a running Adler-32 checksum with the bytes buf[0..len-1] and
01572    return the updated checksum.  If buf is Z_NULL, this function returns the
01573    required initial value for the checksum.
01574 
01575      An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
01576    much faster.
01577 
01578    Usage example:
01579 
01580      uLong adler = adler32(0L, Z_NULL, 0);
01581 
01582      while (read_buffer(buffer, length) != EOF) {
01583        adler = adler32(adler, buffer, length);
01584      }
01585      if (adler != original_adler) error();
01586 */
01587 
01588 /*
01589 ZEXTERN uLong ZEXPORT adler32_combine OF((uLong adler1, uLong adler2,
01590                                           z_off_t len2));
01591 
01592      Combine two Adler-32 checksums into one.  For two sequences of bytes, seq1
01593    and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for
01594    each, adler1 and adler2.  adler32_combine() returns the Adler-32 checksum of
01595    seq1 and seq2 concatenated, requiring only adler1, adler2, and len2.  Note
01596    that the z_off_t type (like off_t) is a signed integer.  If len2 is
01597    negative, the result has no meaning or utility.
01598 */
01599 
01600 ZEXTERN uLong ZEXPORT crc32   OF((uLong crc, const Bytef *buf, uInt len));
01601 /*
01602      Update a running CRC-32 with the bytes buf[0..len-1] and return the
01603    updated CRC-32.  If buf is Z_NULL, this function returns the required
01604    initial value for the crc.  Pre- and post-conditioning (one's complement) is
01605    performed within this function so it shouldn't be done by the application.
01606 
01607    Usage example:
01608 
01609      uLong crc = crc32(0L, Z_NULL, 0);
01610 
01611      while (read_buffer(buffer, length) != EOF) {
01612        crc = crc32(crc, buffer, length);
01613      }
01614      if (crc != original_crc) error();
01615 */
01616 
01617 /*
01618 ZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2));
01619 
01620      Combine two CRC-32 check values into one.  For two sequences of bytes,
01621    seq1 and seq2 with lengths len1 and len2, CRC-32 check values were
01622    calculated for each, crc1 and crc2.  crc32_combine() returns the CRC-32
01623    check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and
01624    len2.
01625 */
01626 
01627 
01628                         /* various hacks, don't look :) */
01629 
01630 /* deflateInit and inflateInit are macros to allow checking the zlib version
01631  * and the compiler's view of z_stream:
01632  */
01633 ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level,
01634                                      const char *version, int stream_size));
01635 ZEXTERN int ZEXPORT inflateInit_ OF((z_streamp strm,
01636                                      const char *version, int stream_size));
01637 ZEXTERN int ZEXPORT deflateInit2_ OF((z_streamp strm, int  level, int  method,
01638                                       int windowBits, int memLevel,
01639                                       int strategy, const char *version,
01640                                       int stream_size));
01641 ZEXTERN int ZEXPORT inflateInit2_ OF((z_streamp strm, int  windowBits,
01642                                       const char *version, int stream_size));
01643 ZEXTERN int ZEXPORT inflateBackInit_ OF((z_streamp strm, int windowBits,
01644                                          unsigned char FAR *window,
01645                                          const char *version,
01646                                          int stream_size));
01647 #define deflateInit(strm, level) \
01648         deflateInit_((strm), (level), ZLIB_VERSION, (int)sizeof(z_stream))
01649 #define inflateInit(strm) \
01650         inflateInit_((strm), ZLIB_VERSION, (int)sizeof(z_stream))
01651 #define deflateInit2(strm, level, method, windowBits, memLevel, strategy) \
01652         deflateInit2_((strm),(level),(method),(windowBits),(memLevel),\
01653                       (strategy), ZLIB_VERSION, (int)sizeof(z_stream))
01654 #define inflateInit2(strm, windowBits) \
01655         inflateInit2_((strm), (windowBits), ZLIB_VERSION, \
01656                       (int)sizeof(z_stream))
01657 #define inflateBackInit(strm, windowBits, window) \
01658         inflateBackInit_((strm), (windowBits), (window), \
01659                       ZLIB_VERSION, (int)sizeof(z_stream))
01660 
01661 #ifndef Z_SOLO
01662 
01663 /* gzgetc() macro and its supporting function and exposed data structure.  Note
01664  * that the real internal state is much larger than the exposed structure.
01665  * This abbreviated structure exposes just enough for the gzgetc() macro.  The
01666  * user should not mess with these exposed elements, since their names or
01667  * behavior could change in the future, perhaps even capriciously.  They can
01668  * only be used by the gzgetc() macro.  You have been warned.
01669  */
01670 struct gzFile_s {
01671     unsigned have;
01672     unsigned char *next;
01673     z_off64_t pos;
01674 };
01675 ZEXTERN int ZEXPORT gzgetc_ OF((gzFile file));  /* backward compatibility */
01676 #ifdef Z_PREFIX_SET
01677 #  undef z_gzgetc
01678 #  define z_gzgetc(g) \
01679           ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : gzgetc(g))
01680 #else
01681 #  define gzgetc(g) \
01682           ((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : gzgetc(g))
01683 #endif
01684 
01685 /* provide 64-bit offset functions if _LARGEFILE64_SOURCE defined, and/or
01686  * change the regular functions to 64 bits if _FILE_OFFSET_BITS is 64 (if
01687  * both are true, the application gets the *64 functions, and the regular
01688  * functions are changed to 64 bits) -- in case these are set on systems
01689  * without large file support, _LFS64_LARGEFILE must also be true
01690  */
01691 #ifdef Z_LARGE64
01692    ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *));
01693    ZEXTERN z_off64_t ZEXPORT gzseek64 OF((gzFile, z_off64_t, int));
01694    ZEXTERN z_off64_t ZEXPORT gztell64 OF((gzFile));
01695    ZEXTERN z_off64_t ZEXPORT gzoffset64 OF((gzFile));
01696    ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off64_t));
01697    ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off64_t));
01698 #endif
01699 
01700 #if !defined(ZLIB_INTERNAL) && defined(Z_WANT64)
01701 #  ifdef Z_PREFIX_SET
01702 #    define z_gzopen z_gzopen64
01703 #    define z_gzseek z_gzseek64
01704 #    define z_gztell z_gztell64
01705 #    define z_gzoffset z_gzoffset64
01706 #    define z_adler32_combine z_adler32_combine64
01707 #    define z_crc32_combine z_crc32_combine64
01708 #  else
01709 #    define gzopen gzopen64
01710 #    define gzseek gzseek64
01711 #    define gztell gztell64
01712 #    define gzoffset gzoffset64
01713 #    define adler32_combine adler32_combine64
01714 #    define crc32_combine crc32_combine64
01715 #  endif
01716 #  ifndef Z_LARGE64
01717      ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *));
01718      ZEXTERN z_off_t ZEXPORT gzseek64 OF((gzFile, z_off_t, int));
01719      ZEXTERN z_off_t ZEXPORT gztell64 OF((gzFile));
01720      ZEXTERN z_off_t ZEXPORT gzoffset64 OF((gzFile));
01721      ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off_t));
01722      ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off_t));
01723 #  endif
01724 #else
01725    ZEXTERN gzFile ZEXPORT gzopen OF((const char *, const char *));
01726    ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile, z_off_t, int));
01727    ZEXTERN z_off_t ZEXPORT gztell OF((gzFile));
01728    ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile));
01729    ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t));
01730    ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t));
01731 #endif
01732 
01733 #else /* Z_SOLO */
01734 
01735    ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t));
01736    ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t));
01737 
01738 #endif /* !Z_SOLO */
01739 
01740 /* hack for buggy compilers */
01741 #if !defined(ZUTIL_H) && !defined(NO_DUMMY_DECL)
01742     struct internal_state {int dummy;};
01743 #endif
01744 
01745 /* undocumented functions */
01746 ZEXTERN const char   * ZEXPORT zError           OF((int));
01747 ZEXTERN int            ZEXPORT inflateSyncPoint OF((z_streamp));
01748 ZEXTERN const z_crc_t FAR * ZEXPORT get_crc_table    OF((void));
01749 ZEXTERN int            ZEXPORT inflateUndermine OF((z_streamp, int));
01750 ZEXTERN int            ZEXPORT inflateResetKeep OF((z_streamp));
01751 ZEXTERN int            ZEXPORT deflateResetKeep OF((z_streamp));
01752 #if defined(_WIN32) && !defined(Z_SOLO)
01753 ZEXTERN gzFile         ZEXPORT gzopen_w OF((const wchar_t *path,
01754                                             const char *mode));
01755 #endif
01756 #if defined(STDC) || defined(Z_HAVE_STDARG_H)
01757 #  ifndef Z_SOLO
01758 ZEXTERN int            ZEXPORTVA gzvprintf Z_ARG((gzFile file,
01759                                                   const char *format,
01760                                                   va_list va));
01761 #  endif
01762 #endif
01763 
01764 #ifdef __cplusplus
01765 }
01766 #endif
01767 
01768 #endif /* ZLIB_H */