PHP实现计算两个时间戳之间的时间长度

/**
 * 返回两个时间的相距时间，*年*月*日*时*分*秒
 * @param int $one_time 时间一
 * @param int $two_time 时间二
 * @param int $return_type 默认值为0，0/不为0则拼接返回，1/*秒，2/*分*秒，3/*时*分*秒/，4/*日*时*分*秒，5/*月*日*时*分*秒，6/*年*月*日*时*分*秒
 * @param array $format_array 格式化字符，例，array('年', '月', '日', '时', '分', '秒')
 * @return String or false
 */
public function getRemainderTime($one_time, $two_time, $return_type=0, $format_array=array('年', '月', '日', '时', '分', '秒')){
	if($return_type6){
		return false;
	}
	if(!(is_int($one_time) && is_int($two_time))){
		return false;
	}
	$remainder_seconds = abs($one_time-$two_time);
	//年
	$years = 0;
	if(($return_type==0 || $return_type==6) && $remainder_seconds-31536000>0){
		$years = floor($remainder_seconds/(31536000));
	}
	//月
	$monthes = 0;
	if(($return_type==0 || $return_type>=5) && $remainder_seconds-$years*31536000-2592000>0){
		$monthes = floor(($remainder_seconds-$years*31536000)/(2592000));
	}
	//日
	$days = 0;
	if(($return_type==0 || $return_type>=4) && $remainder_seconds-$years*31536000-$monthes*2592000-86400>0){
		$days = floor(($remainder_seconds-$years*31536000-$monthes*2592000)/(86400));
	}
	//时
	$hours = 0;
	if(($return_type==0 || $return_type>=3) && $remainder_seconds-$years*31536000-$monthes*2592000-$days*86400-3600>0){
		$hours = floor(($remainder_seconds-$years*31536000-$monthes*2592000-$days*86400)/3600);
	}
	//分
	$minutes = 0;
	if(($return_type==0 || $return_type>=2) && $remainder_seconds-$years*31536000-$monthes*2592000-$days*86400-$hours*3600-60>0){
		$minutes = floor(($remainder_seconds-$years*31536000-$monthes*2592000-$days*86400-$hours*3600)/60);
	}
	//秒
	$seconds = $remainder_seconds-$years*31536000-$monthes*2592000-$days*86400-$hours*3600-$minutes*60;
	$return = false;
	switch ($return_type){
		case 0:
			if($years>0){
				$return = $years.$format_array[0].$monthes.$format_array[1].$days.$format_array[2].$hours.$format_array[3].$minutes.$format_array[4].$seconds.$format_array[5];
			}else if($monthes>0){
				$return = $monthes.$format_array[1].$days.$format_array[2].$hours.$format_array[3].$minutes.$format_array[4].$seconds.$format_array[5];
			}else if($days>0){
				$return = $days.$format_array[2].$hours.$format_array[3].$minutes.$format_array[4].$seconds.$format_array[5];
			}else if($hours>0){
				$return = $hours.$format_array[3].$minutes.$format_array[4].$seconds.$format_array[5];
			}else if($minutes>0){
				$return = $minutes.$format_array[4].$seconds.$format_array[5];
			}else{
				$return = $seconds.$format_array[5];
			}
			break;
		case 1:
			$return = $seconds.$format_array[5];
			break;
		case 2:
			$return = $minutes.$format_array[4].$seconds.$format_array[5];
			break;
		case 3:
			$return = $hours.$format_array[3].$minutes.$format_array[4].$seconds.$format_array[5];
			break;
		case 4:
			$return = $days.$format_array[2].$hours.$format_array[3].$minutes.$format_array[4].$seconds.$format_array[5];
			break;
		case 5:
			$return = $monthes.$format_array[1].$days.$format_array[2].$hours.$format_array[3].$minutes.$format_array[4].$seconds.$format_array[5];
			break;
		case 6:
			$return = $years.$format_array[0].$monthes.$format_array[1].$days.$format_array[2].$hours.$format_array[3].$minutes.$format_array[4].$seconds.$format_array[5];
			break;
		default:
			$return = false;
	}
	return $return;
}

PHP