PHP友好的时间显示函数

function format_date($time){
$t = time-$time;
$f = array(
'31536000'=>'年前',
'2592000'=>'个月前',
'604800'=>'星期前',
'86400'=>'天前',
'3600'=>'小时前',
'60'=>'分钟前',
'1'=>'刚刚',
);

foreach($if as $k=>$v){
if(0 != $c = floor($t/(int)$k)){
return $v;
}
}
}