protected function getMask()
    {
        if (!isset($this->mask)) {
            if (!$this->isMasked()) {
                throw new FrameException('Cannot get mask: frame is not masked');
            }
            $this->mask = substr($this->buffer, $this->getMaskOffset(), $this->getMaskSize());
        }
        return $this->mask;
    }
protected function getMask()
    {
        if (!isset($this->mask)) {
            if (!$this->isMasked()) {
                throw new FrameException('Cannot get mask: frame is not masked');
            }
            $this->mask = substr($this->buffer, $this->getMaskOffset(), $this->getMaskSize());
        }
        return $this->mask;
    }
protected function getMask ( ) { if ( ! isset ( $ this -> mask ) ) { if ( ! $ this -> isMasked ( ) ) { throw new FrameException ( 'Cannot get mask: frame is not masked' ) ; } $ this -> mask = substr ( $ this -> buffer , $ this -> getMaskOffset ( ) , $ this -> getMaskSize ( ) ) ; } return $ this -> mask ; }
Gets the mask

@throws FrameException
@return string
Gets the mask