A small debug Class with backtrace

class Dbg{
	public static $_mode = false;
 
	/** Short hand for print_r exit; **/ 
	public function prd($d){
		if(!self::$_mode)
			return;
 
		echo '<pre>';
			print_r($d);
		echo '</pre>';
		exit;
	}
 
	/** shorthand for print_r with pre **/
	public static function pr($d){
		if(!self::$_mode)
			return;
 
		echo '<pre>';
			print_r($d);
		echo '</pre>';
	}	
 
	/**
	 * shorthand print_r with backtrace
	 */
 
	public static function debug($d){
		if(!self::$_mode)
			return;
 
		$file = 'undefined';
		$line = 'undefined';
 
		$backtraceInfo = debug_backtrace();
 
		$countTrace = count($backtraceInfo);
 
		if($countTrace == 1){
			$line = $backtraceInfo[0]['line'];
			$file = $backtraceInfo[0]['file'];		
		}
		elseif($countTrace){
			$line = $backtraceInfo[$countTrace -2]['line'];
			$file = $backtraceInfo[$countTrace -2]['file'];				
		}
 
		echo sprintf('<div class="debug"><strong>Zeile: %s, Datei: %s</strong><br /><pre>', $line, $file);
		print_r($d);
		echo  '</pre></div>';
	}
 
}