this.bitCount = LongAddables.create();
    }

    // Used by serialization
    LockFreeBitArray(long[] data) {
      checkArgument(data.length > 0, "data length is zero!");
      this.data = new AtomicLongArray(data);
      this.bitCount = LongAddables.create();
      long bitCount = 0;
      for (long value : data) {
        bitCount += Long.bitCount(value);
      }

      writeVariableLengthLong(vN)
    }
  }

  /** Used for tags and subidentifiers. */
  private fun writeVariableLengthLong(v: Long) {
    val sink = sink()
    val bitCount = 64 - java.lang.Long.numberOfLeadingZeros(v)
    val byteCount = (bitCount + 6) / 7
    for (shift in (byteCount - 1) * 7 downTo 0 step 7) {
      val lastBit = if (shift == 0) 0 else 0b1000_0000

      sink.writeByte(accumulator.toInt())
    }
  }

  fun encodedLength(bytes: ByteString): Int {
    var bitCount = 0L

    for (i in 0 until bytes.size) {
      val byteIn = bytes[i] and 0xff
      bitCount += CODE_BIT_COUNTS[byteIn].toLong()
    }

    return ((bitCount + 7) shr 3).toInt() // Round up to an even byte.
  }

  fun decode(
    source: BufferedSource,
    byteCount: Long,

   *
   * @since 22.0
   */
  public long approximateElementCount() {
    long bitSize = bits.bitSize();
    long bitCount = bits.bitCount();

    /**
     * Each insertion is expected to reduce the # of clear bits by a factor of
     * `numHashFunctions/bitSize`. So, after n insertions, expected bitCount is `bitSize * (1 - (1 -
     * numHashFunctions/bitSize)^n)`. Solving that for n, and approximating `ln x` as `x - 1` when x

        key8[ 6 ] = (byte) ( ( key[ 5 ] << 2 ) | ( ( key[ 6 ] & 0xFF ) >>> 6 ) );
        key8[ 7 ] = (byte) ( key[ 6 ] << 1 );
        for ( int i = 0; i < key8.length; i++ ) {
            key8[ i ] ^= Integer.bitCount(key8[ i ] ^ 1) & 1;
        }
        return key8;
    }

    /**
     * Default provider is BouncyCastleProvider.
     * For registering custom provider

  }

  /** Returns the value for the setting `id`, or 0 if unset. */
  operator fun get(id: Int): Int = values[id]

  /** Returns the number of settings that have values assigned. */
  fun size(): Int = Integer.bitCount(set)

  // TODO: honor this setting.
  fun getEnablePush(defaultValue: Boolean): Boolean {
    val bit = 1 shl ENABLE_PUSH
    return if (bit and set != 0) values[ENABLE_PUSH] == 1 else defaultValue
  }

  public void testIsPowerOfTwo() {
    for (int x : ALL_INTEGER_CANDIDATES) {
      // Checks for a single bit set.
      BigInteger bigX = BigInteger.valueOf(x);
      boolean expected = (bigX.signum() > 0) && (bigX.bitCount() == 1);
      assertEquals(expected, IntMath.isPowerOfTwo(x));
    }
  }

  public void testLog2ZeroAlwaysThrows() {
    for (RoundingMode mode : ALL_ROUNDING_MODES) {

  public void testIsPowerOfTwo() {
    for (int x : ALL_INTEGER_CANDIDATES) {
      // Checks for a single bit set.
      BigInteger bigX = BigInteger.valueOf(x);
      boolean expected = (bigX.signum() > 0) && (bigX.bitCount() == 1);
      assertEquals(expected, IntMath.isPowerOfTwo(x));
    }
  }

  public void testLog2ZeroAlwaysThrows() {
    for (RoundingMode mode : ALL_ROUNDING_MODES) {

    return 1L << ((Long.SIZE - 1) - Long.numberOfLeadingZeros(x));
  }

  /**
   * Returns {@code true} if {@code x} represents a power of two.
   *
   * <p>This differs from {@code Long.bitCount(x) == 1}, because {@code
   * Long.bitCount(Long.MIN_VALUE) == 1}, but {@link Long#MIN_VALUE} is not a power of two.
   */
  // Whenever both tests are cheap and functional, it's faster to use &, | instead of &&, ||

    return 1L << ((Long.SIZE - 1) - Long.numberOfLeadingZeros(x));
  }

  /**
   * Returns {@code true} if {@code x} represents a power of two.
   *
   * <p>This differs from {@code Long.bitCount(x) == 1}, because {@code
   * Long.bitCount(Long.MIN_VALUE) == 1}, but {@link Long#MIN_VALUE} is not a power of two.
   */
  // Whenever both tests are cheap and functional, it's faster to use &, | instead of &&, ||