php 计算时间差的方法

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;  
     $hours = intval($remain/3600);  
     $remain = $remain%3600;  
     $mins = intval($remain/60);  
     $secs = $remain%60;  
     $res = array("day" => $days,"hour" => $hours,"min" => $mins,"sec" => $secs);  
     return $res;  
}