}
  }

  @AndroidIncompatible // TODO(cpovirk): File bug for BigDecimal.doubleValue().
  public void testBigToDouble() {
    for (BigInteger b : ALL_BIGINTEGER_CANDIDATES) {
      if (b.doubleValue() != DoubleUtils.bigToDouble(b)) {
        failFormat(
            "Converting %s to double: expected doubleValue %s but got bigToDouble %s",
            b, b.doubleValue(), DoubleUtils.bigToDouble(b));
      }
    }
  }

    }
  }

  @AndroidIncompatible // TODO(cpovirk): File bug for BigDecimal.doubleValue().
  public void testBigToDouble() {
    for (BigInteger b : ALL_BIGINTEGER_CANDIDATES) {
      if (b.doubleValue() != DoubleUtils.bigToDouble(b)) {
        failFormat(
            "Converting %s to double: expected doubleValue %s but got bigToDouble %s",
            b, b.doubleValue(), DoubleUtils.bigToDouble(b));
      }
    }
  }

    assertEquals(0, Defaults.defaultValue(long.class).longValue());
    assertEquals(0.0f, Defaults.defaultValue(float.class).floatValue());
    assertThat(Defaults.defaultValue(double.class).doubleValue()).isEqualTo(0.0d);
    assertNull(Defaults.defaultValue(void.class));
    assertNull(Defaults.defaultValue(String.class));
  }

    private BigDecimalToDoubleRounder() {}

    @Override
    double roundToDoubleArbitrarily(BigDecimal bigDecimal) {
      return bigDecimal.doubleValue();
    }

    @Override
    int sign(BigDecimal bigDecimal) {
      return bigDecimal.signum();
    }

    @Override
    BigDecimal toX(double d, RoundingMode mode) {
      return new BigDecimal(d);

  @Override
  public float floatValue() {
    return (float) sum();
  }

  /** Returns the {@link #sum} as a {@code double} after a widening primitive conversion. */
  @Override
  public double doubleValue() {
    return (double) sum();
  }

  private void writeObject(ObjectOutputStream s) throws IOException {
    s.defaultWriteObject();
    s.writeLong(sum());
  }

    return longBitsToDouble(significand | ONE_BITS);
  }

  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();

    // So we can ignore the bottom 8, except for rounding. See doubleValue() for more.
    return (float) ((value >>> 1) | (value & 1)) * 2f;
  }

  /**
   * Returns the value of this {@code UnsignedLong} as a {@code double}, analogous to a widening
   * primitive conversion from {@code long} to {@code double}, and correctly rounded.
   */
  @Override
  public double doubleValue() {
    if (value >= 0) {
      return (double) value;

    // So we can ignore the bottom 8, except for rounding. See doubleValue() for more.
    return (float) ((value >>> 1) | (value & 1)) * 2f;
  }

  /**
   * Returns the value of this {@code UnsignedLong} as a {@code double}, analogous to a widening
   * primitive conversion from {@code long} to {@code double}, and correctly rounded.
   */
  @Override
  public double doubleValue() {
    if (value >= 0) {
      return (double) value;

  @Override
  public float floatValue() {
    return (float) sum();
  }

  /** Returns the {@link #sum} as a {@code double} after a widening primitive conversion. */
  @Override
  public double doubleValue() {
    return (double) sum();
  }

  private void writeObject(ObjectOutputStream s) throws IOException {
    s.defaultWriteObject();
    s.writeLong(sum());
  }

  @Override
  public float floatValue() {
    return (float) sum();
  }

  /** Returns the {@link #sum} as a {@code double} after a widening primitive conversion. */
  @Override
  public double doubleValue() {
    return (double) sum();
  }

  private void writeObject(ObjectOutputStream s) throws IOException {
    s.defaultWriteObject();
    s.writeLong(sum());
  }