zlib.h

Last change: 2008-02-03 This is the source code of KCeasy。

     This function can be used to decompress a whole file at once if the
   input file is mmap'ed.

     uncompress returns Z_OK if success, Z_MEM_ERROR if there was not
   enough memory, Z_BUF_ERROR if there was not enough room in the output
   buffer, or Z_DATA_ERROR if the input data was corrupted or incomplete.
*/


typedef voidp gzFile;

ZEXTERN gzFile ZEXPORT gzopen  OF((const char *path, const char *mode));
/*
     Opens a gzip (.gz) file for reading or writing. The mode parameter
   is as in fopen ("rb" or "wb") but can also include a compression level
   ("wb9") or a strategy: 'f' for filtered data as in "wb6f", 'h' for
   Huffman only compression as in "wb1h", or 'R' for run-length encoding
   as in "wb1R". (See the description of deflateInit2 for more information
   about the strategy parameter.)

     gzopen can be used to read a file which is not in gzip format; in this
   case gzread will directly read from the file without decompression.

     gzopen returns NULL if the file could not be opened or if there was
   insufficient memory to allocate the (de)compression state; errno
   can be checked to distinguish the two cases (if errno is zero, the
   zlib error is Z_MEM_ERROR).  */

ZEXTERN gzFile ZEXPORT gzdopen  OF((int fd, const char *mode));
/*
     gzdopen() associates a gzFile with the file descriptor fd.  File
   descriptors are obtained from calls like open, dup, creat, pipe or
   fileno (in the file has been previously opened with fopen).
   The mode parameter is as in gzopen.
     The next call of gzclose on the returned gzFile will also close the
   file descriptor fd, just like fclose(fdopen(fd), mode) closes the file
   descriptor fd. If you want to keep fd open, use gzdopen(dup(fd), mode).
     gzdopen returns NULL if there was insufficient memory to allocate
   the (de)compression state.
*/

ZEXTERN int ZEXPORT gzsetparams OF((gzFile file, int level, int strategy));
/*
     Dynamically update the compression level or strategy. See the description
   of deflateInit2 for the meaning of these parameters.
     gzsetparams returns Z_OK if success, or Z_STREAM_ERROR if the file was not
   opened for writing.
*/

ZEXTERN int ZEXPORT    gzread  OF((gzFile file, voidp buf, unsigned len));
/*
     Reads the given number of uncompressed bytes from the compressed file.
   If the input file was not in gzip format, gzread copies the given number
   of bytes into the buffer.
     gzread returns the number of uncompressed bytes actually read (0 for
   end of file, -1 for error). */

ZEXTERN int ZEXPORT    gzwrite OF((gzFile file,
                                   voidpc buf, unsigned len));
/*
     Writes the given number of uncompressed bytes into the compressed file.
   gzwrite returns the number of uncompressed bytes actually written
   (0 in case of error).
*/

ZEXTERN int ZEXPORTVA   gzprintf OF((gzFile file, const char *format, ...));
/*
     Converts, formats, and writes the args to the compressed file under
   control of the format string, as in fprintf. gzprintf returns the number of
   uncompressed bytes actually written (0 in case of error).  The number of
   uncompressed bytes written is limited to 4095. The caller should assure that
   this limit is not exceeded. If it is exceeded, then gzprintf() will return
   return an error (0) with nothing written. In this case, there may also be a
   buffer overflow with unpredictable consequences, which is possible only if
   zlib was compiled with the insecure functions sprintf() or vsprintf()
   because the secure snprintf() or vsnprintf() functions were not available.
*/

ZEXTERN int ZEXPORT gzputs OF((gzFile file, const char *s));
/*
      Writes the given null-terminated string to the compressed file, excluding
   the terminating null character.
      gzputs returns the number of characters written, or -1 in case of error.
*/

ZEXTERN char * ZEXPORT gzgets OF((gzFile file, char *buf, int len));
/*
      Reads bytes from the compressed file until len-1 characters are read, or
   a newline character is read and transferred to buf, or an end-of-file
   condition is encountered.  The string is then terminated with a null
   character.
      gzgets returns buf, or Z_NULL in case of error.
*/

ZEXTERN int ZEXPORT    gzputc OF((gzFile file, int c));
/*
      Writes c, converted to an unsigned char, into the compressed file.
   gzputc returns the value that was written, or -1 in case of error.
*/

ZEXTERN int ZEXPORT    gzgetc OF((gzFile file));
/*
      Reads one byte from the compressed file. gzgetc returns this byte
   or -1 in case of end of file or error.
*/

ZEXTERN int ZEXPORT    gzungetc OF((int c, gzFile file));
/*
      Push one character back onto the stream to be read again later.
   Only one character of push-back is allowed.  gzungetc() returns the
   character pushed, or -1 on failure.  gzungetc() will fail if a
   character has been pushed but not read yet, or if c is -1. The pushed
   character will be discarded if the stream is repositioned with gzseek()
   or gzrewind().
*/

ZEXTERN int ZEXPORT    gzflush OF((gzFile file, int flush));
/*
     Flushes all pending output into the compressed file. The parameter
   flush is as in the deflate() function. The return value is the zlib
   error number (see function gzerror below). gzflush returns Z_OK if
   the flush parameter is Z_FINISH and all output could be flushed.
     gzflush should be called only when strictly necessary because it can
   degrade compression.
*/

ZEXTERN z_off_t ZEXPORT    gzseek OF((gzFile file,
                                      z_off_t offset, int whence));
/*
      Sets the starting position for the next gzread or gzwrite on the
   given compressed file. The offset represents a number of bytes in the
   uncompressed data stream. The whence parameter is defined as in lseek(2);
   the value SEEK_END is not supported.
     If the file is opened for reading, this function is emulated but can be
   extremely slow. If the file is opened for writing, only forward seeks are
   supported; gzseek then compresses a sequence of zeroes up to the new
   starting position.

      gzseek returns the resulting offset location as measured in bytes from
   the beginning of the uncompressed stream, or -1 in case of error, in
   particular if the file is opened for writing and the new starting position
   would be before the current position.
*/

ZEXTERN int ZEXPORT    gzrewind OF((gzFile file));
/*
     Rewinds the given file. This function is supported only for reading.

   gzrewind(file) is equivalent to (int)gzseek(file, 0L, SEEK_SET)
*/

ZEXTERN z_off_t ZEXPORT    gztell OF((gzFile file));
/*
     Returns the starting position for the next gzread or gzwrite on the
   given compressed file. This position represents a number of bytes in the
   uncompressed data stream.

   gztell(file) is equivalent to gzseek(file, 0L, SEEK_CUR)
*/

ZEXTERN int ZEXPORT gzeof OF((gzFile file));
/*
     Returns 1 when EOF has previously been detected reading the given
   input stream, otherwise zero.
*/

ZEXTERN int ZEXPORT gzdirect OF((gzFile file));
/*
     Returns 1 if file is being read directly without decompression, otherwise
   zero.
*/

ZEXTERN int ZEXPORT    gzclose OF((gzFile file));
/*
     Flushes all pending output if necessary, closes the compressed file
   and deallocates all the (de)compression state. The return value is the zlib
   error number (see function gzerror below).
*/

ZEXTERN const char * ZEXPORT gzerror OF((gzFile file, int *errnum));
/*
     Returns the error message for the last error which occurred on the
   given compressed file. errnum is set to zlib error number. If an
   error occurred in the file system and not in the compression library,
   errnum is set to Z_ERRNO and the application may consult errno
   to get the exact error code.
*/

ZEXTERN void ZEXPORT gzclearerr OF((gzFile file));
/*
     Clears the error and end-of-file flags for file. This is analogous to the
   clearerr() function in stdio. This is useful for continuing to read a gzip
   file that is being written concurrently.
*/

                        /* checksum functions */

/*
     These functions are not related to compression but are exported
   anyway because they might be useful in applications using the
   compression library.
*/

ZEXTERN uLong ZEXPORT adler32 OF((uLong adler, const Bytef *buf, uInt len));
/*
     Update a running Adler-32 checksum with the bytes buf[0..len-1] and
   return the updated checksum. If buf is NULL, this function returns
   the required initial value for the checksum.
   An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
   much faster. Usage example:

     uLong adler = adler32(0L, Z_NULL, 0);

     while (read_buffer(buffer, length) != EOF) {
       adler = adler32(adler, buffer, length);
     }
     if (adler != original_adler) error();
*/

ZEXTERN uLong ZEXPORT adler32_combine OF((uLong adler1, uLong adler2,
                                          z_off_t len2));
/*
     Combine two Adler-32 checksums into one.  For two sequences of bytes, seq1
   and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for
   each, adler1 and adler2.  adler32_combine() returns the Adler-32 checksum of
   seq1 and seq2 concatenated, requiring only adler1, adler2, and len2.
*/

ZEXTERN uLong ZEXPORT crc32   OF((uLong crc, const Bytef *buf, uInt len));
/*
     Update a running CRC-32 with the bytes buf[0..len-1] and return the
   updated CRC-32. If buf is NULL, this function returns the required initial
   value for the for the crc. Pre- and post-conditioning (one's complement) is
   performed within this function so it shouldn't be done by the application.
   Usage example:

     uLong crc = crc32(0L, Z_NULL, 0);

     while (read_buffer(buffer, length) != EOF) {
       crc = crc32(crc, buffer, length);
     }
     if (crc != original_crc) error();
*/

ZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2));

/*
     Combine two CRC-32 check values into one.  For two sequences of bytes,
   seq1 and seq2 with lengths len1 and len2, CRC-32 check values were
   calculated for each, crc1 and crc2.  crc32_combine() returns the CRC-32
   check value of seq1 and seq2 concatenated, requiring only crc1, crc2, and
   len2.
*/


                        /* various hacks, don't look :) */

/* deflateInit and inflateInit are macros to allow checking the zlib version
 * and the compiler's view of z_stream:
 */
ZEXTERN int ZEXPORT deflateInit_ OF((z_streamp strm, int level,