/** Updates this hasher with the given byte. */
  protected abstract void update(byte b);

  /** Updates this hasher with the given bytes. */
  protected void update(byte[] b) {
    update(b, 0, b.length);
  }

  /** Updates this hasher with {@code len} bytes starting at {@code off} in the given buffer. */
  protected void update(byte[] b, int off, int len) {

  @Override
  @CanIgnoreReturnValue
  public final Hasher putChar(char c) {
    buffer.putChar(c);
    munchIfFull();
    return this;
  }

  @Override
  @CanIgnoreReturnValue
  public final Hasher putInt(int i) {
    buffer.putInt(i);
    munchIfFull();
    return this;
  }

  @Override
  @CanIgnoreReturnValue
  public final Hasher putLong(long l) {
    buffer.putLong(l);

 * </ul>
 *
 * <h3>Providing input to a hash function</h3>
 *
 * <p>The primary way to provide the data that your hash function should act on is via a {@link
 * Hasher}. Obtain a new hasher from the hash function using {@link #newHasher}, "push" the relevant
 * data into it using methods like {@link Hasher#putBytes(byte[])}, and finally ask for the {@code
 * HashCode} when finished using {@link Hasher#hash}. (See an {@linkplain #newHasher example} of

 * </ul>
 *
 * <h3>Providing input to a hash function</h3>
 *
 * <p>The primary way to provide the data that your hash function should act on is via a {@link
 * Hasher}. Obtain a new hasher from the hash function using {@link #newHasher}, "push" the relevant
 * data into it using methods like {@link Hasher#putBytes(byte[])}, and finally ask for the {@code
 * HashCode} when finished using {@link Hasher#hash}. (See an {@linkplain #newHasher example} of

    return newHasher(input.remaining()).putBytes(input).hash();
  }

  /** In-memory stream-based implementation of Hasher. */
  private final class BufferingHasher extends AbstractHasher {
    final ExposedByteArrayOutputStream stream;

    BufferingHasher(int expectedInputSize) {
      this.stream = new ExposedByteArrayOutputStream(expectedInputSize);
    }

    @Override
    public Hasher putByte(byte b) {
      stream.write(b);

    // https://github.com/aappleby/smhasher/blob/master/src/main.cpp
    HashTestUtils.verifyHashFunction(hf, 32, 0xB0F57EE3);
  }

  public void testParanoid() {
    HashFn hf =
        new HashFn() {
          @Override
          public byte[] hash(byte[] input, int seed) {
            Hasher hasher = murmur3_32(seed).newHasher();

    }
    HashCode[] codes = new HashCode[hashers.size()];
    for (int i = 0; i < hashers.size(); i++) {
      codes[i] = hashers.get(i).hash();
    }
    for (int i = 1; i < codes.length; i++) {
      assertEquals(codes[i - 1], codes[i]);
    }
  }

  public void testPutStringWithLowSurrogate() {

    HashCode hash31 = HashCode.fromInt(31);
    HashCode hash32 = HashCode.fromInt(32);
    assertEquals(hash32, Hashing.combineUnordered(ImmutableList.of(hash32)));
    assertEquals(HashCode.fromInt(64), Hashing.combineUnordered(ImmutableList.of(hash32, hash32)));
    assertEquals(
        HashCode.fromInt(96), Hashing.combineUnordered(ImmutableList.of(hash32, hash32, hash32)));
    assertEquals(

      RandomHasherAction.pickAtRandom(random2).performAction(random2, ImmutableSet.of(hasher2));
    }

    Assert.assertEquals(expected1, hasher1.hash());
    Assert.assertEquals(expected2, hasher2.hash());
  }

  static HashCode randomHash(HashFunction hashFunction, Random random, int numActions) {
    Hasher hasher = hashFunction.newHasher();

      // We need to ensure that at least 4 bytes have been put into the hasher or else
      // Hasher#hash will throw an ISE.
      int intToPut = random.nextInt();
      for (Hasher hasher : sinksAndControl) {
        hasher.putInt(intToPut);
      }
      for (Sink sink : sinks) {
        HashCode unused = sink.hash();
      }

      byte[] expected = controlSink.hash().asBytes();
      for (Sink sink : sinks) {