'===========================================================================
' Subject: .ZIP FILE HEADER                   Date: 06-07-97 (00:00)       
'  Author: Ian Campbell                       Code: Text                   
'  Origin: dm.campbell@ns.sympatico.ca      Packet: FAQS.ABC
'===========================================================================
' Ever wondered what was in the zip file header? Here it is, straight from the
' Pkware homepage. Have Fun!
'
' Ian Campbell


  A.  Local file header:

        local file header signature     4 bytes  (0x04034b50)
        version needed to extract       2 bytes
        general purpose bit flag        2 bytes
        compression method              2 bytes
        last mod file time              2 bytes
        last mod file date              2 bytes
        crc-32                          4 bytes
        compressed size                 4 bytes
        uncompressed size               4 bytes
        filename length                 2 bytes
        extra field length              2 bytes

        filename (variable size)
        extra field (variable size)


  B.  Data descriptor:

        crc-32                          4 bytes
        compressed size                 4 bytes
        uncompressed size               4 bytes

      This descriptor exists only if bit 3 of the general
      purpose bit flag is set (see below).  It is byte aligned
      and immediately follows the last byte of compressed data.

  C.  Central directory structure:

      [file header] . . .  end of central dir record

      file header:

        central file header signature   4 bytes  (0x02014b50)
        version made by                 2 bytes
        version needed to extract       2 bytes
        general purpose bit flag        2 bytes
        compression method              2 bytes
        last mod file time              2 bytes
        last mod file date              2 bytes
        crc-32                          4 bytes
        compressed size                 4 bytes
        uncompressed size               4 bytes
        filename length                 2 bytes
        extra field length              2 bytes
        file comment length             2 bytes
        disk number start               2 bytes
        internal file attributes        2 bytes
        external file attributes        4 bytes
        relative offset of local header 4 bytes

        filename (variable size)
        extra field (variable size)
        file comment (variable size)

      End of central dir record:

        end of central dir signature    4 bytes  (0x06054b50)
        number of this disk             2 bytes
        number of the disk with the
        start of the central directory  2 bytes
        total number of entries in
        the central dir on this disk    2 bytes
        total number of entries in
        the central dir                 2 bytes
        size of the central directory   4 bytes
        offset of start of central
        directory with respect to
        the starting disk number        4 bytes
        zipfile comment length          2 bytes
        zipfile comment (variable size)