PHP calculates the size of a folder

http://blog.1dnet.net/?post=839

//http://blog.1dnet.net
    function dirSize($directoty){
    	$dir_size=0;

    	if($dir_handle=@opendir($directoty))
    	{
    		while($filename=readdir($dir_handle)){
    			$subFile=$directoty.DIRECTORY_SEPARATOR.$filename;
    			if($filename=='.'||$filename=='..'){
    				continue;
    			}elseif (is_dir($subFile))
    			{
    				$dir_size+=dirSize($subFile);
    			}elseif (is_file($subFile)){
    				$dir_size+=filesize($subFile);
    			}
    		}
    		closedir($dir_handle);
    	}
    	return ($dir_size);
    }

    $dir_size=dirSize("xym");
    echo round($dir_size/pow(1024,1),2)."KB";
?>