Obfuscate php code

A class to obfuscate php code:

if (!defined('T_ML_COMMENT')) {
   define('T_ML_COMMENT', T_COMMENT);
} else {
   define('T_DOC_COMMENT', T_ML_COMMENT);
}

class ofusca {
 	var $target = '/var/www/target';
 	var $source = '/var/www/source';
 	var $variables = array();
 	var $n = 0;

 	private function output($file) {
		return $this->target.str_replace($this->source,'',$file);
 	}
 	public function  __construct() {
		$this->readdir($this->source);
 	}
 	private function readdir($dir) {
 		@mkdir($this->output($dir), 0777);
		$directory = dir($dir);
		while ($file = $directory->read())
		{
		    if ($file!="." & $file!=".."){
				if (is_dir($dir.'/'.$file)) {
					$this->readdir($dir.'/'.$file);
				} else {
					$ext = substr($file, stripos($file,'.'));
			    	$this->parse($dir.'/'.$file, $ext);
				}
			}
		}
		$directory->close();
 	}
	function callback_variables($matches) {
		$var = $matches[0];
		if (array_key_exists($var, $this->variables)) {
			return $this->variables[$var];
		} else {
			$this->n = $this->n + 1;
			if (($var!='$this') && ($var!='$this')) {
			    $this->variables[$var] = '$v'.$this->n;
			    return $this->variables[$var];
			} else {
				return $var;
			}
		}
	}

    function strip_comments($source) {
        $tokens = token_get_all($source);
        $ret = "";
        foreach ($tokens as $token) {
           if (is_string($token)) {
              $ret.= $token;
           } else {
              list($id, $text) = $token;
              switch ($id) {
                 case T_COMMENT:
                 case T_ML_COMMENT: 
                 case T_DOC_COMMENT:
                    break;

                 default:
                    $ret.= $text;
                    break;
              }
           }
        }
        return $ret;
    }
	private function parse_array_php($miarray) {
		$text = $miarray[1];
		$text = '<?'.$this->parse_php($text).'?>';
		return $text;
	}
	private function parse_php($text) {
	    //strip comments
	    $text = $this->strip_comments($text);
	    //remover tabs
	    $text = preg_replace('/([\t])*/', '', $text);
	    //remover intros
	    $text = preg_replace('/([\r\n])/', ' ', $text);
		//remover dobles espacios
		$text = preg_replace('/([ ]{2,})/', ' ', $text);
	    //cahnge vars
		$text = preg_replace_callback('/\$[a-zA-Z]+/', array($this,'callback_variables'), $text);
		return trim($text);
	}
 	private function parse($file, $extension) {
 		echo $file.'<br>';
		$text = file_get_contents($file);
 		switch ($extension) {
 			case '.php':
		 		$text = $this->parse_php($text);
 			break;
 			case '.html': //views
 				$text = preg_replace_callback('|\<\?([\=]?(php)?[^>]+)\?>|', array($this,'parse_array_php'), $text);
 			break;
 		}
	    file_put_contents($this->output($file), $text);
 	}
 }