php中用数组的方法设置cookies

<?php 
        function set_cronology($name,$value,$duration=7){ 
                $duration=time()+(3600*24*$duration); 
                $max_stored_values=5; 
                if(isset($_COOKIE[$name])){ 
                        foreach($_COOKIE[$name] as $prop_crono=>$val_crono){ 
                                if($val_crono==$value) 
                                        return; 
                        } 
                        if($prop_crono<$max_stored_values) 
                                setcookie($name.'['.($prop_crono+1).']',$value,$duration); 
                        else{ 
                                array_shift($_COOKIE[$name]); 
                                setcookie("$name[$max_stored_values]",$value,$duration); 
                        } 
                }else 
                        setcookie($name.'[0]',$value,$duration); 
                return; 
        } 
?>