PHP packages a set of files into a zip package.

/**
* Zip file creation class.
* Makes zip files.
*
* @access  public
*/
class zipfile
{
    /**
     * Array to store compressed data
     *
     * @public array    $datasec
*/
    public $datasec      = array();

    /**
     * Central directory
     *
     * @public array    $ctrl_dir
*/
    public $ctrl_dir     = array();

    /**
     * End of central directory record
     *
     * @public string   $eof_ctrl_dir
*/
    public $eof_ctrl_dir = "x50x4bx05x06x00x00x00x00";

    /**
     * Last offset position
     *
     * @public integer  $old_offset
*/
    public $old_offset   = 0;


    /**
     * Converts an Unix timestamp to a four byte DOS date and time format (date
     * in high two bytes, time in low two bytes allowing magnitude comparison).
     *
     * @param  integer  the current Unix timestamp
     *
     * @return integer  the current date in a four byte DOS format
     *
     * @access private
*/
    function unix2DosTime($unixtime = 0) {
        $timearray = ($unixtime == 0) ? getdate() : getdate($unixtime);

        if ($timearray['year'] < 1980) {
            $timearray['year']    = 1980;
            $timearray['mon']     = 1;
            $timearray['mday']    = 1;
            $timearray['hours']   = 0;
            $timearray['minutes'] = 0;
            $timearray['seconds'] = 0;
        } // end if

        return (($timearray['year'] - 1980) << 25) | ($timearray['mon'] << 21) | ($timearray['mday'] << 16) |
                ($timearray['hours'] << 11) | ($timearray['minutes'] << 5) | ($timearray['seconds'] >> 1);
    }// end of the 'unix2DosTime()' method


    /**
     * Adds "file" to archive
     *
     * @param  string   file contents
     * @param  string   name of the file in the archive (may contains the path)
     * @param  integer  the current timestamp
     *
     * @access public
*/
    function addFile($data, $name, $time = 0)
    {
        $name     = str_replace('\', '/', $name);

        $dtime    = dechex($this->unix2DosTime($time));
        $hexdtime = 'x' . $dtime[6] . $dtime[7]
                  . 'x' . $dtime[4] . $dtime[5]
                  . 'x' . $dtime[2] . $dtime[3]
                  . 'x' . $dtime[0] . $dtime[1];
        eval('$hexdtime = "' . $hexdtime . '";');

        $fr   = "x50x4bx03x04";
        $fr   .= "x14x00";            // ver needed to extract
        $fr   .= "x00x00";            // gen purpose bit flag
        $fr   .= "x08x00";            // compression method
        $fr   .= $hexdtime;             // last mod time and date

        // "local file header" segment
        $unc_len = strlen($data);
        $crc     = crc32($data);
        $zdata   = gzcompress($data);
        $zdata   = substr(substr($zdata, 0, strlen($zdata) - 4), 2); // fix crc bug
        $c_len   = strlen($zdata);
        $fr      .= pack('V', $crc);             // crc32
        $fr      .= pack('V', $c_len);           // compressed filesize
        $fr      .= pack('V', $unc_len);         // uncompressed filesize
        $fr      .= pack('v', strlen($name));    // length of filename
        $fr      .= pack('v', 0);                // extra field length
        $fr      .= $name;

        // "file data" segment
        $fr .= $zdata;

        // "data descriptor" segment (optional but necessary if archive is not
        // served as file)
        $fr .= pack('V', $crc);                 // crc32
        $fr .= pack('V', $c_len);               // compressed filesize
        $fr .= pack('V', $unc_len);             // uncompressed filesize

        // add this entry to array
        $this -> datasec[] = $fr;

        // now add to central directory record
        $cdrec = "x50x4bx01x02";
        $cdrec .= "x00x00";                // version made by
        $cdrec .= "x14x00";                // version needed to extract
        $cdrec .= "x00x00";                // gen purpose bit flag
        $cdrec .= "x08x00";                // compression method
        $cdrec .= $hexdtime;                 // last mod time & date
        $cdrec .= pack('V', $crc);           // crc32
        $cdrec .= pack('V', $c_len);         // compressed filesize
        $cdrec .= pack('V', $unc_len);       // uncompressed filesize
        $cdrec .= pack('v', strlen($name) ); // length of filename
        $cdrec .= pack('v', 0 );             // extra field length
        $cdrec .= pack('v', 0 );             // file comment length
        $cdrec .= pack('v', 0 );             // disk number start
        $cdrec .= pack('v', 0 );             // internal file attributes
        $cdrec .= pack('V', 32 );            // external file attributes - 'archive' bit set

        $cdrec .= pack('V', $this -> old_offset ); // relative offset of local header
        $this -> old_offset += strlen($fr);

        $cdrec .= $name;

        // optional extra field, file comment goes here
        // save to central directory
        $this -> ctrl_dir[] = $cdrec;
    } // end of the 'addFile()' method


    /**
     * Dumps out file
     *
     * @return  string  the zipped file
     *
     * @access public
*/
    function file()
    {
        $data    = implode('', $this -> datasec);
        $ctrldir = implode('', $this -> ctrl_dir);

        return
            $data .
            $ctrldir .
            $this -> eof_ctrl_dir .
            pack('v', sizeof($this -> ctrl_dir)) .  // total # of entries "on this disk"
            pack('v', sizeof($this -> ctrl_dir)) .  // total # of entries overall
            pack('V', strlen($ctrldir)) .           // size of central dir
            pack('V', strlen($data)) .              // offset to start of central dir
            "x00x00";                             // .zip file comment length
    }// end of the 'file()' method


    /**
     * A Wrapper of original addFile Function
     *
     * Created By Hasin Hayder at 29th Jan, 1:29 AM
     *
     * @param array An Array of files with relative/absolute path to be added in Zip File
     *
     * @access public
*/
    function addFiles($files /*Only Pass Array*/)
    {
        foreach($files as $file)
        {
        if (is_file($file)) //directory check
        {
            $data = implode("",file($file));
                    $this->addFile($data,$file);
                }
        }
    }

    /**
     * A Wrapper of original file Function
     *
     * Created By Hasin Hayder at 29th Jan, 1:29 AM
     *
     * @param string Output file name
     *
     * @access public
*/
    function output($file)
    {
        $fp=fopen($file,"w");
        fwrite($fp,$this->file());
        fclose($fp);
    }
} // end of the 'zipfile' class