php路由URI

<?
    function seo_uri (){
        $uri_arr = explode("/",trim($_SERVER['REQUEST_URI'],'/'));
        $web_root_str = strtr(WEB_ROOT,'/','\');
        $root_path_arr = explode('\',trim($web_root_str,'\'));
        $root_path_count = count($root_path_arr);
        foreach($uri_arr as $key=>$val){
            if($val==$root_path_arr[$root_path_count-1]){
                $uri_arr_start = $key;
            }
        }
        if($uri_arr_start>='0'){
            $uri_new = array_slice($uri_arr,$uri_arr_start+1);
        }else{
            $uri_new = $uri_arr;
        }
        $uri['mod']=isset($_GET['mod'])?$_GET['mod']:(isset($uri_new['0'])?(!empty($uri_new['0'])?$uri_new['0']:"index"):"index");
        $uri['act']=isset($_GET['act'])?$_GET['act']:(isset($uri_new['1'])?(!empty($uri_new['1'])?$uri_new['1']:"index"):"index");
        if(count($uri_new)>2){
            $uri['uri'] = array_slice($uri_new,1);
        }
        return $uri;
    }
?>