2つのタイムスタンプ間の時間差の計算

//機能:2つのタイムスタンプの差を計算する日時分秒
   //$begin_time開始タイムスタンプ
   //$end_time終了タイムスタンプ

    private function timediff($begin_time,$end_time)
    {
    	if($begin_time < $end_time){
    		$starttime = $begin_time;
    		$endtime = $end_time;
    	}else{
    		$starttime = $end_time;
    		$endtime = $begin_time;
    	}
    
    	//    
    	$timediff = $endtime-$starttime;
    	$days = intval($timediff/86400);
    	//     
    	//$remain = $timediff%86400;             $remain，             ，       
    	$hours = intval($timediff/3600);
    	//     
    	//$remain = $remain%3600;
    	$mins = intval($timediff/60);
    	//    
    	$secs = $timediff%60;
    	$res = array("day" => $days,"hour" => $hours,"min" => $mins,"sec" => $secs);
    	return $res;
    }