}

  MessageDigestHashFunction(String algorithmName, int bytes, String toString) {
    this.toString = checkNotNull(toString);
    this.prototype = getMessageDigest(algorithmName);
    int maxLength = prototype.getDigestLength();
    checkArgument(
        bytes >= 4 && bytes <= maxLength, "bytes (%s) must be >= 4 and < %s", bytes, maxLength);
    this.bytes = bytes;
    this.supportsClone = supportsClone(prototype);
  }

   * well-formed.
   *
   * <p>This method returns {@code true} if and only if {@code Arrays.equals(bytes, new
   * String(bytes, UTF_8).getBytes(UTF_8))} does, but is more efficient in both time and space.
   */
  public static boolean isWellFormed(byte[] bytes) {
    return isWellFormed(bytes, 0, bytes.length);
  }

  /**

    byte[] bytes = HashTestUtils.ascii(input);

    Checksum checksum = supplier.get();
    checksum.update(bytes, 0, bytes.length);
    long value = checksum.getValue();

    String toString = "name";
    HashFunction func = new ChecksumHashFunction(supplier, 32, toString);
    assertEquals(toString, func.toString());
    assertEquals(value, func.hashBytes(bytes).padToLong());
  }

  }

  public void testWrite_bytes() throws IOException {
    assertArrayEquals(new byte[0], sink.getBytes());
    sink.write(bytes);

    assertTrue(sink.wasStreamOpened() && sink.wasStreamClosed());
    assertArrayEquals(bytes, sink.getBytes());
  }

  public void testWriteFrom_inputStream() throws IOException {
    ByteArrayInputStream in = new ByteArrayInputStream(bytes);
    sink.writeFrom(in);

  }

  static TestSuite suiteForBytes(
      ByteSourceFactory factory, byte[] bytes, String name, String desc, boolean slice) {
    TestSuite suite = new TestSuite(name + " [" + desc + "]");
    for (Method method : testMethods) {
      suite.addTest(new ByteSourceTester(factory, bytes, name, desc, method));
    }

    if (slice && bytes.length > 0) {
      // test a random slice() of the ByteSource
      Random random = new Random();

  }

  /** Convenience method to compute a fingerprint on a full bytes array. */
  private static long fingerprint(byte[] bytes) {
    return fingerprint(bytes, bytes.length);
  }

  /** Convenience method to compute a fingerprint on a subset of a byte array. */
  private static long fingerprint(byte[] bytes, int length) {
    return HASH_FN.hashBytes(bytes, 0, length).asLong();
  }

  /**

    Random r = new Random(1234567);
    for (int length = 0; length < 1000; length++) {
      byte[] bytes = new byte[length];
      r.nextBytes(bytes);
      assertCrc(referenceCrc(bytes), bytes);
    }
  }

  private static int referenceCrc(byte[] bytes) {
    int crc = ~0;
    for (byte b : bytes) {
      crc = (crc >>> 8) ^ Crc32cHashFunction.Crc32cHasher.BYTE_TABLE[(crc ^ b) & 0xFF];
    }
    return ~crc;

    PrimitiveSink sink = mock(PrimitiveSink.class);
    OutputStream out = Funnels.asOutputStream(sink);
    byte[] bytes = {1, 2, 3, 4};
    out.write(255);
    out.write(bytes);
    out.write(bytes, 1, 2);
    verify(sink).putByte((byte) 255);
    verify(sink).putBytes(bytes);
    verify(sink).putBytes(bytes, 1, 2);
  }

  public void testSerialization() {
    assertSame(

  @CanIgnoreReturnValue
  @Override
  Hasher putByte(byte b);

  @CanIgnoreReturnValue
  @Override
  Hasher putBytes(byte[] bytes);

  @CanIgnoreReturnValue
  @Override
  Hasher putBytes(byte[] bytes, int off, int len);

  @CanIgnoreReturnValue
  @Override
  Hasher putBytes(ByteBuffer bytes);

  @CanIgnoreReturnValue
  @Override
  Hasher putShort(short s);

  @CanIgnoreReturnValue
  @Override

  }

  @SuppressWarnings("unchecked")
  static <T> T reserialize(T object) {
    try {
      ByteArrayOutputStream bytes = new ByteArrayOutputStream();
      ObjectOutputStream out = new ObjectOutputStream(bytes);
      out.writeObject(object);
      ObjectInputStream in = new ObjectInputStream(new ByteArrayInputStream(bytes.toByteArray()));
      return (T) in.readObject();
    } catch (IOException | ClassNotFoundException e) {