/**
  * CAPABILITY response parser
  */
 protected function parseCapability($str, $trusted = false)
 {
     $str = preg_replace('/^\\* CAPABILITY /i', '', $str);
     $this->capability = explode(' ', strtoupper($str));
     if (!empty($this->prefs['disabled_caps'])) {
         $this->capability = array_diff($this->capability, $this->prefs['disabled_caps']);
     }
     if (!isset($this->prefs['literal+']) && in_array('LITERAL+', $this->capability)) {
         $this->prefs['literal+'] = true;
     }
     if (preg_match('/(\\[| )MUPDATE=.*/', $str)) {
         self::$mupdate = true;
     }
     if ($trusted) {
         $this->capability_readed = true;
     }
 }