this.arithmetic = arithmetic;
    }

    @Override
    public int add(int a, int b) {
      return arithmetic.add(a, b);
    }

    @Override
    public int minus(int a, int b) {
      return arithmetic.minus(a, b);
    }

    @Override
    public String toString() {
      return arithmetic.toString();
    }
  }

  private static class FailsToForwardParameters implements Adder {

          // The possible number of two byte characters
          TWO_BYTE_ROUNDTRIPPABLE_CHARACTERS;

  // 2048
  private static final long THREE_BYTE_SURROGATES = 2 * 1024;

  // 61,440 [chars 0x0800 to 0xFFFF, minus surrogates]
  private static final long THREE_BYTE_ROUNDTRIPPABLE_CHARACTERS =
      0xFFFF - 0x0800 + 1 - THREE_BYTE_SURROGATES;

  // 2,650,112
  private static final long EXPECTED_THREE_BYTE_ROUNDTRIPPABLE_COUNT =

   * _could_, so we could keep it as it is. Or we could convince ourselves that hash flooding is
   * unlikely in practice there, too.)
   */

  /**
   * Returns an immutable set containing the given elements, minus duplicates, in the order each was
   * first specified. That is, if multiple elements are {@linkplain Object#equals equal}, all except
   * the first are ignored.
   */
  public static <E> ImmutableSet<E> of(E e1, E e2) {

      for (int i = 0; i < len; ++i) {
        bitBuffer |= bytes[off + i] & 0xFF;
        bitBuffer <<= 8; // Add additional zero byte in the end.
      }
      // Position of first character is length of bitBuffer minus bitsPerChar.
      int bitOffset = (len + 1) * 8 - alphabet.bitsPerChar;
      int bitsProcessed = 0;
      while (bitsProcessed < len * 8) {

   * collection in unspecified order.
   *
   * @param collection the elements that the set should contain
   * @return a new {@code CompactHashSet} containing those elements (minus duplicates)
   */
  public static <E extends @Nullable Object> CompactHashSet<E> create(
      Collection<? extends E> collection) {
    CompactHashSet<E> set = createWithExpectedSize(collection.size());

      this.arithmetic = arithmetic;
    }

    @Override
    public int add(int a, int b) {
      return arithmetic.add(a, b);
    }

    @Override
    public int minus(int a, int b) {
      return arithmetic.minus(a, b);
    }

    @Override
    public String toString() {
      return arithmetic.toString();
    }
  }

  private static class FailsToForwardParameters implements Adder {

  }

  /**
   * Parses the specified string as a single-precision floating point value. The ASCII character
   * {@code '-'} (<code>'&#92;u002D'</code>) is recognized as the minus sign.
   *
   * <p>Unlike {@link Float#parseFloat(String)}, this method returns {@code null} instead of
   * throwing an exception if parsing fails. Valid inputs are exactly those accepted by {@link

    // array slot is read and written exactly once. However, it can have very poor memory locality:
    // benchmarking shows it can take 7 times longer than the other two in some cases. The other two
    // do n swaps, minus a delta (0 or 2 for Reversal, gcd(d, n) for Successive), so that's about
    // twice as many reads and writes. But benchmarking shows that they usually perform better than

          // The possible number of two byte characters
          TWO_BYTE_ROUNDTRIPPABLE_CHARACTERS;

  // 2048
  private static final long THREE_BYTE_SURROGATES = 2 * 1024;

  // 61,440 [chars 0x0800 to 0xFFFF, minus surrogates]
  private static final long THREE_BYTE_ROUNDTRIPPABLE_CHARACTERS =
      0xFFFF - 0x0800 + 1 - THREE_BYTE_SURROGATES;

  // 2,650,112
  private static final long EXPECTED_THREE_BYTE_ROUNDTRIPPABLE_COUNT =

        .compile(fpPattern);
  }

  /**
   * Parses the specified string as a double-precision floating point value. The ASCII character
   * {@code '-'} (<code>'&#92;u002D'</code>) is recognized as the minus sign.
   *
   * <p>Unlike {@link Double#parseDouble(String)}, this method returns {@code null} instead of
   * throwing an exception if parsing fails. Valid inputs are exactly those accepted by {@link