* {@link LongMath} respectively.
 *
 * @author Louis Wasserman
 * @since 11.0
 */
@GwtCompatible
public final class BigIntegerMath {
  /**
   * Returns the smallest power of two greater than or equal to {@code x}. This is equivalent to
   * {@code BigInteger.valueOf(2).pow(log2(x, CEILING))}.
   *
   * @throws IllegalArgumentException if {@code x <= 0}
   * @since 20.0
   */

  static boolean isFinite(double d) {
    return getExponent(d) <= MAX_EXPONENT;
  }

  static boolean isNormal(double d) {
    return getExponent(d) >= MIN_EXPONENT;
  }

  /*
   * Returns x scaled by a power of 2 such that it is in the range [1, 2). Assumes x is positive,
   * normal, and finite.
   */
  static double scaleNormalize(double x) {
    long significand = doubleToRawLongBits(x) & SIGNIFICAND_MASK;

    SetBuilderImpl<E> copy() {
      return this;
    }

    @Override
    ImmutableSet<E> build() {
      return ImmutableSet.of();
    }
  }

  // We use power-of-2 tables, and this is the highest int that's a power of 2
  static final int MAX_TABLE_SIZE = Ints.MAX_POWER_OF_TWO;

  // Represents how tightly we can pack things, as a maximum.
  private static final double DESIRED_LOAD_FACTOR = 0.7;

@GwtIncompatible
abstract class Striped64 extends Number {
  /*
   * This class maintains a lazily-initialized table of atomically
   * updated variables, plus an extra "base" field. The table size
   * is a power of two. Indexing uses masked per-thread hash codes.
   * Nearly all declarations in this class are package-private,
   * accessed directly by subclasses.
   *
   * Table entries are of class Cell; a variant of AtomicLong padded

/**
 * Very simple powerSet iteration benchmark.
 *
 * @author Kevin Bourrillion
 */
@NullUnmarked
public class PowerSetBenchmark {
  @Param({"2", "4", "8", "16"})
  int elements;

  Set<Set<Integer>> powerSet;

  @BeforeExperiment
  void setUp() {
    Set<Integer> set = ContiguousSet.create(Range.closed(1, elements), integers());
    powerSet = Sets.powerSet(set);
  }

  @Benchmark

    Set<Set<Integer>> powerSet = powerSet(elements);
    assertEquals(1, powerSet.size());
    assertEquals(ImmutableSet.of(ImmutableSet.of()), powerSet);
    assertEquals(0, powerSet.hashCode());
  }

  public void testPowerSetContents() {
    ImmutableSet<Integer> elements = ImmutableSet.of(1, 2, 3);
    Set<Set<Integer>> powerSet = powerSet(elements);
    assertEquals(8, powerSet.size());

  }

  public void testCountOverflow_doesNotThrow() {
    PairedStatsAccumulator accumulator = new PairedStatsAccumulator();
    accumulator.add(ONE_VALUE, OTHER_ONE_VALUE);
    for (int power = 1; power < Long.SIZE - 1; power++) {
      accumulator.addAll(accumulator.snapshot());
    }
    // Should overflow without throwing.
    accumulator.addAll(accumulator.snapshot());
    assertThat(accumulator.count()).isLessThan(0L);

  }

  private static final int MAX_TABLE_SIZE = Ints.MAX_POWER_OF_TWO;

  static int closedTableSize(int expectedEntries, double loadFactor) {
    // Get the recommended table size.
    // Round down to the nearest power of 2.
    expectedEntries = max(expectedEntries, 2);
    int tableSize = Integer.highestOneBit(expectedEntries);
    // Check to make sure that we will not exceed the maximum load factor.

   * can hold setSize elements with the desired load factor.
   */
  @VisibleForTesting
  static int chooseTableSize(int setSize) {
    if (setSize == 1) {
      return 2;
    }
    // Correct the size for open addressing to match desired load factor.
    // Round up to the next highest power of 2.
    int tableSize = Integer.highestOneBit(setSize - 1) << 1;

   * the least significant bit zero is chosen. (In such cases, both of the nearest representable
   * values are even integers; this method returns the one that is a multiple of a greater power of
   * two.)
   *
   * @throws ArithmeticException if {@code mode} is {@link RoundingMode#UNNECESSARY} and {@code x}
   *     is not precisely representable as a {@code double}
   * @since 30.0
   */