*
 * @author Kevin Bourrillion
 * @author Jesse Wilson
 * @author Austin Appleby
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
final class Hashing {
  private Hashing() {}

  /*
   * These should be ints, but we need to use longs to force GWT to do the multiplications with
   * enough precision.
   */
  private static final long C1 = 0xcc9e2d51;

   * specific length.
   *
   * <p>For example, if you need 1024-bit hash codes, you could join two {@link Hashing#sha512} hash
   * functions together: {@code Hashing.concatenating(Hashing.sha512(), Hashing.sha512())}.
   *
   * @since 19.0
   */
  public static HashFunction concatenating(
      HashFunction first, HashFunction second, HashFunction... rest) {

 *
 * @author Kevin Bourrillion
 * @author Jesse Wilson
 * @author Austin Appleby
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
final class Hashing {
  private Hashing() {}

  /*
   * These should be ints, but we need to use longs to force GWT to do the multiplications with
   * enough precision.
   */
  private static final long C1 = 0xcc9e2d51;

    byte result = 0x01;
    // Trick the JVM to prevent it from using the hash function non-polymorphically
    result ^= Hashing.crc32().hashInt(reps).asBytes()[0];
    result ^= Hashing.adler32().hashInt(reps).asBytes()[0];
    result ^= Hashing.fingerprint2011().hashInt(reps).asBytes()[0];
    for (int i = 0; i < reps; i++) {
      result ^= hashFunction.hashBytes(testBytes).asBytes()[0];
    }
    return result;

    byte result = 0x01;
    // Trick the JVM to prevent it from using the hash function non-polymorphically
    result ^= Hashing.crc32().hashInt(reps).asBytes()[0];
    result ^= Hashing.adler32().hashInt(reps).asBytes()[0];
    result ^= Hashing.fingerprint2011().hashInt(reps).asBytes()[0];
    for (int i = 0; i < reps; i++) {
      result ^= hashFunction.hashBytes(testBytes).asBytes()[0];
    }
    return result;

  public void testKnownIntegerInputs() {
    assertHash(593689054, murmur3_32().hashInt(0));
    assertHash(-189366624, murmur3_32().hashInt(-42));
    assertHash(-1134849565, murmur3_32().hashInt(42));
    assertHash(-1718298732, murmur3_32().hashInt(Integer.MIN_VALUE));
    assertHash(-1653689534, murmur3_32().hashInt(Integer.MAX_VALUE));
  }

  public void testKnownLongInputs() {

        Hashing.md5().bits() + Hashing.md5().bits(),
        Hashing.concatenating(Hashing.md5(), Hashing.md5()).bits());
    assertEquals(
        Hashing.md5().bits() + Hashing.murmur3_32().bits(),
        Hashing.concatenating(Hashing.md5(), Hashing.murmur3_32()).bits());
    assertEquals(
        Hashing.md5().bits() + Hashing.murmur3_32().bits() + Hashing.murmur3_128().bits(),

      new Murmur3_32HashFunction(0, /* supplementaryPlaneFix= */ true);

  // We can include the non-BMP fix here because Hashing.goodFastHash stresses that the hash is a
  // temporary-use one. Therefore it shouldn't be persisted.
  static final HashFunction GOOD_FAST_HASH_32 =
      new Murmur3_32HashFunction(Hashing.GOOD_FAST_HASH_SEED, /* supplementaryPlaneFix= */ true);

  private static final int CHUNK_SIZE = 4;

  }

  public void testToString() {
    assertEquals("Hashing.md5()", Hashing.md5().toString());
    assertEquals("Hashing.sha1()", Hashing.sha1().toString());
    assertEquals("Hashing.sha256()", Hashing.sha256().toString());
    assertEquals("Hashing.sha512()", Hashing.sha512().toString());
  }

  private static void assertMessageDigestHashing(byte[] input, String algorithmName) {

    assertEquals(
        "Hashing.hmacMd5(Key[algorithm=HmacMD5, format=RAW])", Hashing.hmacMd5(MD5_KEY).toString());
    assertEquals(
        "Hashing.hmacMd5(Key[algorithm=HmacMD5, format=RAW])", Hashing.hmacMd5(keyData).toString());

    assertEquals(
        "Hashing.hmacSha1(Key[algorithm=HmacSHA1, format=RAW])",
        Hashing.hmacSha1(SHA1_KEY).toString());
    assertEquals(