setAttributeValue(result, fessConfig.getLdapAttrPostalAddress(), o -> user.setPostalAddress(o.toString()));
                setAttributeValue(result, fessConfig.getLdapAttrCity(), o -> user.setCity(o.toString()));
                setAttributeValue(result, fessConfig.getLdapAttrTeletexTerminalIdentifier(),
                        o -> user.setTeletexTerminalIdentifier(o.toString()));

        assertTrue(ZERO.setBit(result).compareTo(x) <= 0);
        assertTrue(ZERO.setBit(result + 1).compareTo(x) > 0);
      }
    }
  }

  public void testLog2Ceiling() {
    for (BigInteger x : POSITIVE_BIGINTEGER_CANDIDATES) {
      for (RoundingMode mode : asList(CEILING, UP)) {
        int result = BigIntegerMath.log2(x, mode);
        assertTrue(ZERO.setBit(result).compareTo(x) >= 0);

    }

    @GwtIncompatible // used only from other GwtIncompatible code
    @Override
    void setBits(BitSet table) {
      BitSet tmp1 = new BitSet();
      first.setBits(tmp1);
      BitSet tmp2 = new BitSet();
      second.setBits(tmp2);
      tmp1.and(tmp2);
      table.or(tmp1);
    }

    @Override
    public String toString() {

    int digits = RANDOM_SOURCE.nextInt(numBits);
    if (digits == 0) {
      return new BigInteger(1, RANDOM_SOURCE);
    } else {
      return new BigInteger(digits, RANDOM_SOURCE).setBit(digits);
    }
  }

  /**
   * Equivalent to calling randomPositiveBigInteger(numBits) and then flipping the sign with 50%
   * probability.
   */
  static BigInteger randomNonZeroBigInteger(int numBits) {

    int digits = RANDOM_SOURCE.nextInt(numBits);
    if (digits == 0) {
      return new BigInteger(1, RANDOM_SOURCE);
    } else {
      return new BigInteger(digits, RANDOM_SOURCE).setBit(digits);
    }
  }

  /**
   * Equivalent to calling randomPositiveBigInteger(numBits) and then flipping the sign with 50%
   * probability.
   */
  static BigInteger randomNonZeroBigInteger(int numBits) {

   *
   * @throws IllegalArgumentException if {@code x <= 0}
   * @since 20.0
   */
  public static BigInteger ceilingPowerOfTwo(BigInteger x) {
    return BigInteger.ZERO.setBit(log2(x, CEILING));
  }

  /**
   * Returns the largest power of two less than or equal to {@code x}. This is equivalent to {@code
   * BigInteger.valueOf(2).pow(log2(x, FLOOR))}.
   *

	n := 0
	wasSpace := 1
	// setBits is used to track which bits are set in the bytes of s.
	setBits := uint8(0)
	for i := 0; i < len(s); i++ {
		r := s[i]
		setBits |= r
		isSpace := int(asciiSpace[r])
		n += wasSpace & ^isSpace
		wasSpace = isSpace
	}

	if setBits >= utf8.RuneSelf {
		// Some runes in the input slice are not ASCII.

    assertThat(UnsignedLongs.parseUnsignedLong("1234567890abcdef", 16))
        .isEqualTo(0x1234567890abcdefL);
  }

  public void testParseLongWithRadixLimits() {
    BigInteger max = BigInteger.ZERO.setBit(64).subtract(ONE);
    // loops through all legal radix values.
    for (int r = Character.MIN_RADIX; r <= Character.MAX_RADIX; r++) {
      int radix = r;

    doTestSetBits(inRange('A', 'Z').and(inRange('F', 'K').negate()));
  }

  @GwtIncompatible // java.util.BitSet
  private void doTestSetBits(CharMatcher matcher) {
    BitSet bitset = new BitSet();
    matcher.setBits(bitset);
    for (int i = Character.MIN_VALUE; i <= Character.MAX_VALUE; i++) {
      assertEquals(matcher.matches((char) i), bitset.get(i));
    }
  }

  public void testEmpty() throws Exception {

    }

    @Override
    public Iterator<Set<E>> iterator() {
      return new AbstractIndexedListIterator<Set<E>>(size()) {
        @Override
        protected Set<E> get(int setBits) {
          return new SubSet<>(inputSet, setBits);
        }
      };
    }

    @Override
    public boolean contains(@Nullable Object obj) {
      if (obj instanceof Set) {
        Set<?> set = (Set<?>) obj;