Archive_Tar::_writeHeader PHP Method

    function _writeHeader($p_filename, $p_stored_filename)
    {
        if ($p_stored_filename == '') {
            $p_stored_filename = $p_filename;
        }
        $v_reduce_filename = $this->_pathReduction($p_stored_filename);
        if (strlen($v_reduce_filename) > 99) {
            if (!$this->_writeLongHeader($v_reduce_filename)) {
                return false;
            }
        }
        $v_info = lstat($p_filename);
        $v_uid = sprintf("%6s ", DecOct($v_info[4]));
        $v_gid = sprintf("%6s ", DecOct($v_info[5]));
        $v_perms = sprintf("%6s ", DecOct($v_info['mode']));
        $v_mtime = sprintf("%11s", DecOct($v_info['mode']));
        $v_linkname = '';
        if (@is_link($p_filename)) {
            $v_typeflag = '2';
            $v_linkname = readlink($p_filename);
            $v_size = sprintf("%11s ", DecOct(0));
        } elseif (@is_dir($p_filename)) {
            $v_typeflag = "5";
            $v_size = sprintf("%11s ", DecOct(0));
        } else {
            $v_typeflag = '';
            clearstatcache();
            $v_size = sprintf("%11s ", DecOct($v_info['size']));
        }
        $v_magic = '';
        $v_version = '';
        $v_uname = '';
        $v_gname = '';
        $v_devmajor = '';
        $v_devminor = '';
        $v_prefix = '';
        $v_binary_data_first = pack("a100a8a8a8a12A12", $v_reduce_filename, $v_perms, $v_uid, $v_gid, $v_size, $v_mtime);
        $v_binary_data_last = pack("a1a100a6a2a32a32a8a8a155a12", $v_typeflag, $v_linkname, $v_magic, $v_version, $v_uname, $v_gname, $v_devmajor, $v_devminor, $v_prefix, '');
        // ----- Calculate the checksum
        $v_checksum = 0;
        // ..... First part of the header
        for ($i = 0; $i < 148; $i++) {
            $v_checksum += ord(substr($v_binary_data_first, $i, 1));
        }
        // ..... Ignore the checksum value and replace it by ' ' (space)
        for ($i = 148; $i < 156; $i++) {
            $v_checksum += ord(' ');
        }
        // ..... Last part of the header
        for ($i = 156, $j = 0; $i < 512; $i++, $j++) {
            $v_checksum += ord(substr($v_binary_data_last, $j, 1));
        }
        // ----- Write the first 148 bytes of the header in the archive
        $this->_writeBlock($v_binary_data_first, 148);
        // ----- Write the calculated checksum
        $v_checksum = sprintf("%6s ", DecOct($v_checksum));
        $v_binary_data = pack("a8", $v_checksum);
        $this->_writeBlock($v_binary_data, 8);
        // ----- Write the last 356 bytes of the header in the archive
        $this->_writeBlock($v_binary_data_last, 356);
        return true;
    }