static void makeVersionInfoBits(int version, BitArray bits) throws WriterException {
    bits.appendBits(version, 6);
    int bchCode = calculateBCHCode(version, VERSION_INFO_POLY);
    bits.appendBits(bchCode, 12);

    if (bits.getSize() != 18) {
      throw new WriterException("should not happen but we got: " + bits.getSize());
    }
  }
  static void makeTypeInfoBits(ErrorCorrectionLevel ecLevel, int maskPattern, BitArray bits)
      throws WriterException {
    if (!QRCode.isValidMaskPattern(maskPattern)) {
      throw new WriterException("Invalid mask pattern");
    }
    int typeInfo = (ecLevel.getBits() << 3) | maskPattern;
    bits.appendBits(typeInfo, 5);

    int bchCode = calculateBCHCode(typeInfo, TYPE_INFO_POLY);
    bits.appendBits(bchCode, 10);

    BitArray maskBits = new BitArray();
    maskBits.appendBits(TYPE_INFO_MASK_PATTERN, 15);
    bits.xor(maskBits);

    if (bits.getSize() != 15) {
      throw new WriterException("should not happen but we got: " + bits.getSize());
    }
  }