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zlib/zlib.h  view on Meta::CPAN

   such as zip.  Those formats provide their own check values. If a custom
   format is developed using the raw deflate format for compressed data, it is
   recommended that a check value such as an adler32 or a crc32 be applied to
   the uncompressed data as is done in the zlib, gzip, and zip formats.  For
   most applications, the zlib format should be used as is. Note that comments
   above on the use in deflateInit2() applies to the magnitude of windowBits.

     windowBits can also be greater than 15 for optional gzip decoding. Add
   32 to windowBits to enable zlib and gzip decoding with automatic header
   detection, or add 16 to decode only the gzip format (the zlib format will
   return a Z_DATA_ERROR).  If a gzip stream is being decoded, strm->adler is
   a crc32 instead of an adler32.

     inflateInit2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
   memory, Z_STREAM_ERROR if a parameter is invalid (such as a null strm). msg
   is set to null if there is no error message.  inflateInit2 does not perform
   any decompression apart from reading the zlib header if present: this will
   be done by inflate(). (So next_in and avail_in may be modified, but next_out
   and avail_out are unchanged.)
*/

zlib/zlib.h  view on Meta::CPAN

*/

ZEXTERN int ZEXPORT inflateGetHeader OF((z_streamp strm,
                                         gz_headerp head));
/*
      inflateGetHeader() requests that gzip header information be stored in the
   provided gz_header structure.  inflateGetHeader() may be called after
   inflateInit2() or inflateReset(), and before the first call of inflate().
   As inflate() processes the gzip stream, head->done is zero until the header
   is completed, at which time head->done is set to one.  If a zlib stream is
   being decoded, then head->done is set to -1 to indicate that there will be
   no gzip header information forthcoming.  Note that Z_BLOCK can be used to
   force inflate() to return immediately after header processing is complete
   and before any actual data is decompressed.

      The text, time, xflags, and os fields are filled in with the gzip header
   contents.  hcrc is set to true if there is a header CRC.  (The header CRC
   was valid if done is set to one.)  If extra is not Z_NULL, then extra_max
   contains the maximum number of bytes to write to extra.  Once done is true,
   extra_len contains the actual extra field length, and extra contains the
   extra field, or that field truncated if extra_max is less than extra_len.