assertThat(set.floor("f")).isNull();
  }

  public void testFloor_elementPresent() {
    ImmutableSortedSet<String> set =
        ImmutableSortedSet.copyOf(new String[] {"e", "a", "e", "f", "b", "i", "d", "a", "c", "k"});
    assertThat(set.floor("f")).isEqualTo("f");
    assertThat(set.floor("j")).isEqualTo("i");
    assertThat(set.floor("q")).isEqualTo("k");
  }

    }

    @Override
    public @Nullable E lower(@ParametricNullness E e) {
      return getElementOrNull(multiset().headMultiset(e, OPEN).lastEntry());
    }

    @Override
    public @Nullable E floor(@ParametricNullness E e) {
      return getElementOrNull(multiset().headMultiset(e, CLOSED).lastEntry());
    }

    @Override
    public @Nullable E ceiling(@ParametricNullness E e) {

/**
 * Benchmarks for the rounding methods of {@code LongMath}.
 *
 * @author Louis Wasserman
 */
@NullUnmarked
public class LongMathRoundingBenchmark {
  @Param({"DOWN", "UP", "FLOOR", "CEILING", "HALF_EVEN", "HALF_UP", "HALF_DOWN"})
  RoundingMode mode;

  private static final long[] positive = new long[ARRAY_SIZE];
  private static final long[] nonzero = new long[ARRAY_SIZE];

    private @Nullable AvlNode<E> floor(Comparator<? super E> comparator, @ParametricNullness E e) {
      int cmp = comparator.compare(e, getElement());
      if (cmp > 0) {
        return (right == null) ? this : MoreObjects.firstNonNull(right.floor(comparator, e), this);
      } else if (cmp == 0) {
        return this;
      } else {
        return (left == null) ? null : left.floor(comparator, e);
      }
    }

  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;
    }

    /*

    assertThat(set.floor("f")).isNull();
  }

  public void testFloor_elementPresent() {
    ImmutableSortedSet<String> set =
        ImmutableSortedSet.copyOf(new String[] {"e", "a", "e", "f", "b", "i", "d", "a", "c", "k"});
    assertThat(set.floor("f")).isEqualTo("f");
    assertThat(set.floor("j")).isEqualTo("i");
    assertThat(set.floor("q")).isEqualTo("k");
  }

  }

  @Override
  public @Nullable E lower(E element) {
    int index = headIndex(element, false) - 1;
    return (index == -1) ? null : elements.get(index);
  }

  @Override
  public @Nullable E floor(E element) {
    int index = headIndex(element, true) - 1;
    return (index == -1) ? null : elements.get(index);
  }

  @Override
  public @Nullable E ceiling(E element) {

  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;
    }

    /*

    private @Nullable AvlNode<E> floor(Comparator<? super E> comparator, @ParametricNullness E e) {
      int cmp = comparator.compare(e, getElement());
      if (cmp > 0) {
        return (right == null) ? this : MoreObjects.firstNonNull(right.floor(comparator, e), this);
      } else if (cmp == 0) {
        return this;
      } else {
        return (left == null) ? null : left.floor(comparator, e);
      }
    }

    }

    @Override
    public @Nullable V lower(@ParametricNullness V v) {
      return getSortedSetDelegate().lower(v);
    }

    @Override
    public @Nullable V floor(@ParametricNullness V v) {
      return getSortedSetDelegate().floor(v);
    }

    @Override
    public @Nullable V ceiling(@ParametricNullness V v) {
      return getSortedSetDelegate().ceiling(v);
    }

    @Override