Something

        $prev_record = null;
        $next_record = null;
        
        if ($res->num_rows() > 0)
        {                     
           
           foreach ($res->result() as $key=>$row)
           {
               list($y,$m,$d) = explode('/',date('Y/m/d',$row->date));
               
               if ($found && is_null($next_record)) {
                    $next_record = array(
                            'y'=>$y,
                            'm'=>$m,
                            'd'=>$d   
                       );
               } else if ((int)$y == (int)$c_y && (int)$m == (int)$c_m && (int)$d == (int)$c_d) {
                   $found = true;
               } else {
                   if (!$found) {
                       $prev_record = array(
                            'y'=>$y,
                            'm'=>$m,
                            'd'=>$d   
                       );
                   } 
               }
               $girls[(int)$y][(int)$m][(int)$d] = site_url('girl/index/'.$y.'/'.$m.'/'.$d);
           }
        }
        
            
        $data['girls'] = $girls;
        $data['prev_girl'] = $prev_record;
        $data['next_girl'] = $next_record;