}

  static double bigToDouble(BigInteger x) {
    // This is an extremely fast implementation of BigInteger.doubleValue(). JDK patch pending.
    BigInteger absX = x.abs();
    int exponent = absX.bitLength() - 1;
    // exponent == floor(log2(abs(x)))
    if (exponent < Long.SIZE - 1) {
      return x.longValue();
    } else if (exponent > MAX_EXPONENT) {
      return x.signum() * POSITIVE_INFINITY;
    }

    /*

   */
  public static UnsignedInteger valueOf(BigInteger value) {
    checkNotNull(value);
    checkArgument(
        value.signum() >= 0 && value.bitLength() <= Integer.SIZE,
        "value (%s) is outside the range for an unsigned integer value",
        value);
    return fromIntBits(value.intValue());
  }

  /**

   */
  @CanIgnoreReturnValue
  public static UnsignedLong valueOf(BigInteger value) {
    checkNotNull(value);
    checkArgument(
        value.signum() >= 0 && value.bitLength() <= Long.SIZE,
        "value (%s) is outside the range for an unsigned long value",
        value);
    return fromLongBits(value.longValue());
  }

  /**