Php makeing a backup

<?php
include_once 'CreateZipFile.inc.php';

$createZip = new CreateZipFile;

$createZip->zipDirectory('binary', '');

$zipFileName = 'backup.zip';
$handle    = fopen($zipFileName, 'wb');
$out      = fwrite($handle, $createZip->getZippedFile());

fclose($handle);

$createZip->forceDownload($zipFileName);

@unlink($zipFileName);
?>

<?php
/**
* Class to dynamically create a zip file (archive) of file(s) and/or directory
*
* @author Rochak Chauhan 
* @package CreateZipFile
* @see Distributed under "General Public License"
*
* @version 1.0
*/

class CreateZipFile {

    public $compressedData = array();
    public $centralDirectory = array(); // central directory
    public $endOfCentralDirectory = "\x50\x4b\x05\x06\x00\x00\x00\x00"; //end of Central directory record
    public $oldOffset = 0;

    /**
     * Function to create the directory where the file(s) will be unzipped
     *
     * @param string $directoryName
     * @access public
     * @return void
     */    
    public function addDirectory($directoryName) {
        $directoryName = str_replace("\\", "/", $directoryName);
        $feedArrayRow = "\x50\x4b\x03\x04";
        $feedArrayRow .= "\x0a\x00";
        $feedArrayRow .= "\x00\x00";
        $feedArrayRow .= "\x00\x00";
        $feedArrayRow .= "\x00\x00\x00\x00";
        $feedArrayRow .= pack("V",0);
        $feedArrayRow .= pack("V",0);
        $feedArrayRow .= pack("V",0);
        $feedArrayRow .= pack("v", strlen($directoryName) );
        $feedArrayRow .= pack("v", 0 );
        $feedArrayRow .= $directoryName;
        $feedArrayRow .= pack("V",0);
        $feedArrayRow .= pack("V",0);
        $feedArrayRow .= pack("V",0);
        $this->compressedData[] = $feedArrayRow;
        $newOffset = strlen(implode("", $this->compressedData));
        $addCentralRecord = "\x50\x4b\x01\x02";
        $addCentralRecord .="\x00\x00";
        $addCentralRecord .="\x0a\x00";
        $addCentralRecord .="\x00\x00";
        $addCentralRecord .="\x00\x00";
        $addCentralRecord .="\x00\x00\x00\x00";
        $addCentralRecord .= pack("V",0);
        $addCentralRecord .= pack("V",0);
        $addCentralRecord .= pack("V",0);
        $addCentralRecord .= pack("v", strlen($directoryName) );
        $addCentralRecord .= pack("v", 0 );
        $addCentralRecord .= pack("v", 0 );
        $addCentralRecord .= pack("v", 0 );
        $addCentralRecord .= pack("v", 0 );
        $addCentralRecord .= pack("V", 16 );
        $addCentralRecord .= pack("V", $this->oldOffset );
        $this->oldOffset = $newOffset;
        $addCentralRecord .= $directoryName;
        $this->centralDirectory[] = $addCentralRecord;
    }

    /**
     * Function to add file(s) to the specified directory in the archive
     *
     * @param string $directoryName
     * @param string $data
     * @return void
     * @access public
     */    
    public function addFile($data, $directoryName)  {
        $directoryName = str_replace("\\", "/", $directoryName);
        $feedArrayRow = "\x50\x4b\x03\x04";
        $feedArrayRow .= "\x14\x00";
        $feedArrayRow .= "\x00\x00";
        $feedArrayRow .= "\x08\x00";
        $feedArrayRow .= "\x00\x00\x00\x00";
        $uncompressedLength = strlen($data);
        $compression = crc32($data);
        $gzCompressedData = gzcompress($data);
        $gzCompressedData = substr( substr($gzCompressedData, 0, strlen($gzCompressedData) - 4), 2);
        $compressedLength = strlen($gzCompressedData);
        $feedArrayRow .= pack("V",$compression);
        $feedArrayRow .= pack("V",$compressedLength);
        $feedArrayRow .= pack("V",$uncompressedLength);
        $feedArrayRow .= pack("v", strlen($directoryName) );
        $feedArrayRow .= pack("v", 0 );
        $feedArrayRow .= $directoryName;
        $feedArrayRow .= $gzCompressedData;
        $feedArrayRow .= pack("V",$compression);
        $feedArrayRow .= pack("V",$compressedLength);
        $feedArrayRow .= pack("V",$uncompressedLength);
        $this->compressedData[] = $feedArrayRow;
        $newOffset = strlen(implode("", $this->compressedData));
        $addCentralRecord = "\x50\x4b\x01\x02";
        $addCentralRecord .="\x00\x00";
        $addCentralRecord .="\x14\x00";
        $addCentralRecord .="\x00\x00";
        $addCentralRecord .="\x08\x00";
        $addCentralRecord .="\x00\x00\x00\x00";
        $addCentralRecord .= pack("V",$compression);
        $addCentralRecord .= pack("V",$compressedLength);
        $addCentralRecord .= pack("V",$uncompressedLength);
        $addCentralRecord .= pack("v", strlen($directoryName) );
        $addCentralRecord .= pack("v", 0 );
        $addCentralRecord .= pack("v", 0 );
        $addCentralRecord .= pack("v", 0 );
        $addCentralRecord .= pack("v", 0 );
        $addCentralRecord .= pack("V", 32 );
        $addCentralRecord .= pack("V", $this->oldOffset );
        $this->oldOffset = $newOffset;
        $addCentralRecord .= $directoryName;
        $this->centralDirectory[] = $addCentralRecord;
    }

    /**
     * Function to return the zip file
     *
     * @return zipfile (archive)
     * @access public
     * @return void
     */
    public function getZippedfile() {
        $data = implode("", $this->compressedData);
        $controlDirectory = implode("", $this->centralDirectory);
        return
        $data.
        $controlDirectory.
        $this->endOfCentralDirectory.
        pack("v", sizeof($this->centralDirectory)).
        pack("v", sizeof($this->centralDirectory)).
        pack("V", strlen($controlDirectory)).
        pack("V", strlen($data)).
        "\x00\x00";
    }

    /**
     *
     * Function to force the download of the archive as soon as it is created
     *
     * @param archiveName string - name of the created archive file
     * @access public
     * @return ZipFile via Header
     */
    public function forceDownload($archiveName) {
        if(ini_get('zlib.output_compression')) {
            ini_set('zlib.output_compression', 'Off');
        }

        // Security checks
        if( $archiveName == "" ) {
            echo "<html><title>Public Photo Directory - Download </title><body><BR><B>ERROR:</B> The download file was NOT SPECIFIED.</body></html>";
            exit;
        }
        elseif ( ! file_exists( $archiveName ) ) {
            echo "<html><title>Public Photo Directory - Download </title><body><BR><B>ERROR:</B> File not found.</body></html>";
            exit;
        }

        header("Pragma: public");
        header("Expires: 0");
        header("Cache-Control: must-revalidate, post-check=0, pre-check=0");
        header("Cache-Control: private",false);
        header("Content-Type: application/zip");
        header("Content-Disposition: attachment; filename=".basename($archiveName).";" );
        header("Content-Transfer-Encoding: binary");
        header("Content-Length: ".filesize($archiveName));
        readfile("$archiveName");
    }

    /**
     * Function to parse a directory to return all its files and sub directories as array
     *
     * @param string $dir
     * @access protected
     * @return array
     */
    protected function parseDirectory($rootPath, $seperator="/"){
        $fileArray=array();
        $handle = opendir($rootPath);
        while( ($file = @readdir($handle))!==false) {
            if($file !='.' && $file !='..'){
                if (is_dir($rootPath.$seperator.$file)){
                    $array=$this->parseDirectory($rootPath.$seperator.$file);
                    $fileArray=array_merge($array,$fileArray);
                }
                else {
                    $fileArray[]=$rootPath.$seperator.$file;
                }
            }
        }        
        return $fileArray;
    }

    /**
     * Function to Zip entire directory with all its files and subdirectories
     *
     * @param string $dirName
     * @access public
     * @return void
     */
    public function zipDirectory($dirName, $outputDir) {
        if (!is_dir($dirName)){
            trigger_error("CreateZipFile FATAL ERROR: Could not locate the specified directory $dirName", E_USER_ERROR);
        }
        $tmp=$this->parseDirectory($dirName);
        $count=count($tmp);
        $this->addDirectory($outputDir);
        for ($i=0;$i<$count;$i++){
            $fileToZip=trim($tmp[$i]);
            $newOutputDir=substr($fileToZip,0,(strrpos($fileToZip,'/')+1));
            $outputDir=$outputDir.$newOutputDir;
            $fileContents=file_get_contents($fileToZip);
            $this->addFile($fileContents,$fileToZip);
        }
    }
}
?>