获取相隔天数

/**
 * 获取相隔天数
 * $begintime int型
 * $endtime   int型
 */
    function time_length($begintime,$endtime){
        if(!is_numeric($begintime)){
            $begintime = to_timespan($begintime);
        }
        if(!is_numeric($endtime)){
            $endtime = to_timespan($endtime);
        }
        $day=0;
        if($endtime==$begintime){
            return $day;
        }
        if($endtime>$begintime){
            $begintime=$begintime+3600*24;
            $begintime=to_date($begintime,"Y-m-d");
            $begintime = to_timespan($begintime);
            $limit_time = $endtime -$begintime;
            $day = intval($limit_time / 3600 / 24+1);
            if($day > 0){
                return $day;
            }else
            {
                return $day;
            }
        }else{
            $begintime=to_date($begintime,"Y-m-d");
            $begintime = to_timespan($begintime);
            $limit_time= $begintime -$endtime;
            $day = intval($limit_time / 3600 / 24+1);
            if(day >0){
                return $day;
            }else
            {
                return $day;
            }
        }
    }