* @param arrays zero or more {@code byte} arrays
   * @return a single array containing all the values from the source arrays, in order
   */
  public static byte[] concat(byte[]... arrays) {
    int length = 0;
    for (byte[] array : arrays) {
      length += array.length;
    }
    byte[] result = new byte[length];
    int pos = 0;
    for (byte[] array : arrays) {
      System.arraycopy(array, 0, result, pos, array.length);

        }
        int byte2 = bytes[index++];
        if (byte2 > (byte) 0xBF
            // Overlong? 5 most significant bits must not all be zero.
            || (byte1 == (byte) 0xE0 && byte2 < (byte) 0xA0)
            // Check for illegal surrogate codepoints.
            || (byte1 == (byte) 0xED && (byte) 0xA0 <= byte2)
            // Third byte trailing-byte test.
            || bytes[index++] > (byte) 0xBF) {
          return false;

              0x13579bdf,
              null,
              "df9b5713"),
          new ExpectedHashCode(
              new byte[] {(byte) 0xcd, (byte) 0xab, (byte) 0x00, (byte) 0x00},
              0x0000abcd,
              null,
              "cdab0000"),
          new ExpectedHashCode(
              new byte[] {
                (byte) 0xef, (byte) 0xcd, (byte) 0xab, (byte) 0x00,

      actual += expected;
    }
    assertEquals(EXPECTED_FOUR_BYTE_ROUNDTRIPPABLE_COUNT, actual);
  }

  private static String newString(char... chars) {
    return new String(chars);
  }

  private static byte[] toByteArray(int... bytes) {
    byte[] realBytes = new byte[bytes.length];
    for (int i = 0; i < bytes.length; i++) {
      realBytes[i] = (byte) bytes[i];
    }
    return realBytes;
  }

  }

  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);
  }

    // loop we keep 56 bytes of state: v, w, x, y, and z.
    long x = load64(bytes, offset);
    long y = load64(bytes, offset + length - 16) ^ K1;
    long z = load64(bytes, offset + length - 56) ^ K0;
    long[] v = new long[2];
    long[] w = new long[2];
    weakHashLength32WithSeeds(bytes, offset + length - 64, length, y, v);

        }
        else {
            javaChecksum = sun.security.krb5.internal.crypto.Aes256.calculateChecksum(keybytes, usage, bytes, 0, bytes.length);
        }

        byte[] mac = PacMac.calculateMacHMACAES(usage, makeKey(keybytes, keybytes.length == 16 ? 17 : 18), bytes);
        checkBytes(javaChecksum, mac);
        checkBytes(Hex.decode(expect), mac);
    }

  public Hasher putBytes(byte[] bytes) {
    checkNotNull(bytes);
    update(bytes);
    return this;
  }

  @Override
  @CanIgnoreReturnValue
  public Hasher putBytes(byte[] bytes, int off, int len) {
    checkPositionIndexes(off, off + len, bytes.length);
    update(bytes, off, len);
    return this;
  }

  @Override
  @CanIgnoreReturnValue
  public Hasher putBytes(ByteBuffer bytes) {
    update(bytes);

    }

    @Override
    public byte[] getExpected(byte[] bytes) {
      if (initialBytes == null) {
        return checkNotNull(bytes);
      } else {
        byte[] result = new byte[initialBytes.length + bytes.length];
        System.arraycopy(initialBytes, 0, result, 0, initialBytes.length);
        System.arraycopy(bytes, 0, result, initialBytes.length, bytes.length);
        return result;
      }
    }

    private byte[] bytes;

    public AppendableByteSource(byte[] initialBytes) {
      this.bytes = initialBytes.clone();
    }

    @Override
    public InputStream openStream() {
      return new In();
    }

    public void append(byte[] b) {
      byte[] newBytes = Arrays.copyOf(bytes, bytes.length + b.length);