/**
 * Skeletal implementation of {@link ImmutableSortedSet#descendingSet()}.
 *
 * @author Louis Wasserman
 */
@GwtIncompatible
@ElementTypesAreNonnullByDefault
final class DescendingImmutableSortedSet<E> extends ImmutableSortedSet<E> {
  private final ImmutableSortedSet<E> forward;

  DescendingImmutableSortedSet(ImmutableSortedSet<E> forward) {
    super(Ordering.from(forward.comparator()).reverse());

/**
 * Skeletal implementation of {@link ImmutableSortedSet#descendingSet()}.
 *
 * @author Louis Wasserman
 */
@GwtIncompatible
@ElementTypesAreNonnullByDefault
final class DescendingImmutableSortedSet<E> extends ImmutableSortedSet<E> {
  private final ImmutableSortedSet<E> forward;

  DescendingImmutableSortedSet(ImmutableSortedSet<E> forward) {
    super(Ordering.from(forward.comparator()).reverse());

  }

  @Override
  ImmutableSortedSet<E> delegateCollection() {
    return (ImmutableSortedSet<E>) super.delegateCollection();
  }

  @Override
  public Comparator<? super E> comparator() {
    return delegateCollection().comparator();
  }

  // Override indexOf() and lastIndexOf() to be O(log N) instead of O(N).

  @GwtIncompatible // ImmutableSortedSet.indexOf

    } else {
      return ~index;
    }
  }

  @Override
  ImmutableSortedSet<E> subSetImpl(
      E fromElement, boolean fromInclusive, E toElement, boolean toInclusive) {
    return tailSetImpl(fromElement, fromInclusive).headSetImpl(toElement, toInclusive);
  }

  @Override
  ImmutableSortedSet<E> tailSetImpl(E fromElement, boolean inclusive) {

 * Collections#singleton(Object)} and {@link java.util.LinkedHashSet} for empty, singleton and
 * regular sets respectively. For the sorted sets, it's a thin wrapper around {@link
 * java.util.TreeSet}.
 *
 * @see ImmutableSortedSet
 * @author Hayward Chan
 */
@ElementTypesAreNonnullByDefault
@SuppressWarnings("serial") // Serialization only done in GWT.
public abstract class ImmutableSet<E> extends ImmutableCollection<E> implements Set<E> {

  private final transient long[] cumulativeCounts;
  private final transient int offset;
  private final transient int length;

  RegularImmutableSortedMultiset(Comparator<? super E> comparator) {
    this.elementSet = ImmutableSortedSet.emptySet(comparator);
    this.cumulativeCounts = ZERO_CUMULATIVE_COUNTS;
    this.offset = 0;
    this.length = 0;
  }

  RegularImmutableSortedMultiset(

/**
 * GWT emulation of {@link RegularImmutableSortedSet}.
 *
 * @author Hayward Chan
 */
@ElementTypesAreNonnullByDefault
final class RegularImmutableSortedSet<E> extends ImmutableSortedSet<E> {

  /** true if this set is a subset of another immutable sorted set. */
  final boolean isSubset;

  private @Nullable Comparator<E> unusedComparatorForSerialization;

  @Override
  @CheckForNull
  public Entry<E> lastEntry() {
    return forward.firstEntry();
  }

  @Override
  public int size() {
    return forward.size();
  }

  @Override
  public ImmutableSortedSet<E> elementSet() {
    return forward.elementSet().descendingSet();
  }

  @Override
  Entry<E> getEntry(int index) {
    return forward.entrySet().asList().reverse().get(index);
  }

  @Override

  @Override
  @CheckForNull
  public Entry<E> lastEntry() {
    return forward.firstEntry();
  }

  @Override
  public int size() {
    return forward.size();
  }

  @Override
  public ImmutableSortedSet<E> elementSet() {
    return forward.elementSet().descendingSet();
  }

  @Override
  Entry<E> getEntry(int index) {
    return forward.entrySet().asList().reverse().get(index);
  }

  @Override

  }

  @Override
  ImmutableList<C> createAsList() {
    if (domain.supportsFastOffset) {
      return new ImmutableAsList<C>() {
        @Override
        ImmutableSortedSet<C> delegateCollection() {
          return RegularContiguousSet.this;
        }

        @Override
        public C get(int i) {
          checkElementIndex(i, size());