PHP formatting time, minutes ago, hours ago

<?php  
//格式化时间，几分钟前，几小时前  
function format_date($time){  
    $t = time()-$time;  
    $f = array(  
        &#39;31536000&#39;=>&#39;年&#39;,  
        &#39;2592000&#39;=>&#39;个月&#39;,  
        &#39;604800&#39;=>&#39;星期&#39;,  
        &#39;86400&#39;=>&#39;天&#39;,  
        &#39;3600&#39;=>&#39;小时&#39;,  
        &#39;60&#39;=>&#39;分钟&#39;,  
        &#39;1&#39;=>&#39;秒&#39; 
    );  
    foreach($f as $k=>$v){  
        if(0 != $c = floor($t/(int)$k)){  
            return $c.$v.&#39;前&#39;;  
        }  
    }  
}  
echo format_date(&#39;1405959031&#39;);  
?>