* values, see {@link com.google.common.primitives.Longs}.
 *
 * @author Louis Wasserman
 * @since 11.0
 */
@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault
public final class LongMath {
  @VisibleForTesting static final long MAX_SIGNED_POWER_OF_TWO = 1L << (Long.SIZE - 2);

  /**
   * Returns the smallest power of two greater than or equal to {@code x}. This is equivalent to

 * values, see {@link com.google.common.primitives.Longs}.
 *
 * @author Louis Wasserman
 * @since 11.0
 */
@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault
public final class LongMath {
  @VisibleForTesting static final long MAX_SIGNED_POWER_OF_TWO = 1L << (Long.SIZE - 2);

  /**
   * Returns the smallest power of two greater than or equal to {@code x}. This is equivalent to

                    .longOpt("verbose")
                    .desc("Produce execution verbose output")
                    .build());
            options.addOption(Option.builder(SHOW_ERRORS)
                    .longOpt("errors")
                    .desc("Produce execution error messages")
                    .build());
            options.addOption(Option.builder(BATCH_MODE)
                    .longOpt("batch-mode")

            options.addOption(Option.builder(ALTERNATE_POM_FILE)
                    .longOpt("file")
                    .hasArg()
                    .desc("Force the use of an alternate POM file (or directory with pom.xml)")
                    .build());
            options.addOption(Option.builder(OFFLINE)
                    .longOpt("offline")
                    .desc("Work offline")
                    .build());

    for (int i = 0; i < LongMath.powersOf10.length; i++) {
      assertEquals(LongMath.checkedPow(10, i), LongMath.powersOf10[i]);
    }
    assertThrows(
        ArithmeticException.class, () -> LongMath.checkedPow(10, LongMath.powersOf10.length));
  }

  @GwtIncompatible // TODO
  public void testConstantsHalfPowersOf10() {
    for (int i = 0; i < LongMath.halfPowersOf10.length; i++) {
      assertEquals(

                .longOpt("quiet")
                .desc("Quiet output - only show errors")
                .build());
        options.addOption(Option.builder(Character.toString(VERBOSE))
                .longOpt("verbose")
                .desc("Produce execution verbose output")
                .build());
        options.addOption(Option.builder(Character.toString(ERRORS))
                .longOpt("errors")

    int startingNumber = LongMath.factorials.length;
    long product = LongMath.factorials[startingNumber - 1];
    // Strip off 2s from this value.
    int shift = Long.numberOfTrailingZeros(product);
    product >>= shift;

    // Use floor(log2(num)) + 1 to prevent overflow of multiplication.
    int productBits = LongMath.log2(product, FLOOR) + 1;
    int bits = LongMath.log2(startingNumber, FLOOR) + 1;

  private static BigInteger oldSlowFactorial(int n) {
    if (n <= 20) {
      return BigInteger.valueOf(LongMath.factorial(n));
    } else {
      int k = 20;
      return BigInteger.valueOf(LongMath.factorial(k)).multiply(oldSlowFactorial(k, n));
    }
  }

  /** Returns the product of {@code n1} exclusive through {@code n2} inclusive. */

            super.prepareOptions(options);
            options.addOption(Option.builder(FORCE)
                    .longOpt("force")
                    .desc("Should overwrite without asking any configuration?")
                    .build());
            options.addOption(Option.builder(YES)
                    .longOpt("yes")
                    .desc("Should imply user answered \"yes\" to all incoming questions?")

  private static BigInteger oldSlowFactorial(int n) {
    if (n <= 20) {
      return BigInteger.valueOf(LongMath.factorial(n));
    } else {
      int k = 20;
      return BigInteger.valueOf(LongMath.factorial(k)).multiply(oldSlowFactorial(k, n));
    }
  }

  /** Returns the product of {@code n1} exclusive through {@code n2} inclusive. */