# File lib/rqrcode/qrcode/qr_util.rb, line 115
    def QRUtil.get_mask( mask_pattern, i, j )
      if mask_pattern > QRMASKCOMPUTATIONS.size
        raise QRCodeRunTimeError, "bad mask_pattern: #{mask_pattern}"  
      end

      return QRMASKCOMPUTATIONS[mask_pattern].call(i, j)
    end