Get max_lenght of numeric field

HI , this is my function :

PHP Code:

        $finfo = $this->db->getFieldData($tabella_db);


        foreach ($finfo as $val) {

             if($val->type == 'varchar'  OR  $val->type == 'text' ){

               $lunghezza =$val->max_length;

               fwrite($fp, "trim|min_length[0]|max_length[$lunghezza]");

             }

            } 


How can i do the same on numeric field (tinyint,smallint etc.)