//   2. Flipping the bits of the constant so we can process a byte at a time. => 0x82F63B78
  private static final int CRC32C_GENERATOR = 0x1EDC6F41; // 0x11EDC6F41
  private static final int CRC32C_GENERATOR_FLIPPED = Integer.reverse(CRC32C_GENERATOR);

  public void testCrc32cByteTable() {
    // See Hacker's Delight 2nd Edition, Figure 14-7.
    int[] expected = new int[256];

  //   2. Flipping the bits of the constant so we can process a byte at a time. => 0x82F63B78
  private static final int CRC32C_GENERATOR = 0x1EDC6F41; // 0x11EDC6F41
  private static final int CRC32C_GENERATOR_FLIPPED = Integer.reverse(CRC32C_GENERATOR);

  public void testCrc32cByteTable() {
    // See Hacker's Delight 2nd Edition, Figure 14-7.
    int[] expected = new int[256];

    new Random(RANDOM_SEED).nextBytes(testBytes);
  }

  // CRC32

  @Benchmark
  byte crc32HashFunction(int reps) {
    return runHashFunction(reps, Hashing.crc32());
  }

  @Benchmark
  byte crc32Checksum(int reps) throws Exception {
    byte result = 0x01;
    for (int i = 0; i < reps; i++) {
      CRC32 checksum = new CRC32();
      checksum.update(testBytes, 0, testBytes.length);

    new Random(RANDOM_SEED).nextBytes(testBytes);
  }

  // CRC32

  @Benchmark
  byte crc32HashFunction(int reps) {
    return runHashFunction(reps, Hashing.crc32());
  }

  @Benchmark
  byte crc32Checksum(int reps) throws Exception {
    byte result = 0x01;
    for (int i = 0; i < reps; i++) {
      CRC32 checksum = new CRC32();
      checksum.update(testBytes, 0, testBytes.length);

          .put(Hashing.crc32c(), EMPTY_STRING, "00000000")
          .put(Hashing.crc32c(), TQBFJOTLD, "04046222")
          .put(Hashing.crc32c(), TQBFJOTLDP, "b3970019")
          .put(Hashing.farmHashFingerprint64(), EMPTY_STRING, "4f40902f3b6ae19a")
          .put(Hashing.farmHashFingerprint64(), TQBFJOTLD, "34511b3bf383beab")

      }
      while (bb.remaining() >= 16) {
        crc0 = computeForWord(crc0);
        crc1 = computeForWord(crc1);
        crc2 = computeForWord(crc2);
        crc3 = computeForWord(crc3);
        crc0 ^= bb.getInt();
        crc1 ^= bb.getInt();
        crc2 ^= bb.getInt();
        crc3 ^= bb.getInt();
      }
    }

    @Override
    protected void processRemaining(ByteBuffer bb) {
      if (finished) {

          .put(Hashing.crc32c(), EMPTY_STRING, "00000000")
          .put(Hashing.crc32c(), TQBFJOTLD, "04046222")
          .put(Hashing.crc32c(), TQBFJOTLDP, "b3970019")
          .put(Hashing.farmHashFingerprint64(), EMPTY_STRING, "4f40902f3b6ae19a")
          .put(Hashing.farmHashFingerprint64(), TQBFJOTLD, "34511b3bf383beab")

func (c ChecksumType) Hasher() hash.Hash {
	switch {
	case c.Is(ChecksumCRC32):
		return crc32.NewIEEE()
	case c.Is(ChecksumCRC32C):
		return crc32.New(crc32.MakeTable(crc32.Castagnoli))
	case c.Is(ChecksumSHA1):
		return sha1.New()
	case c.Is(ChecksumSHA256):
		return sha256.New()
	}
	return nil
}

// Trailing return whether the checksum is trailing.
func (c ChecksumType) Trailing() bool {

	AmzFwdHeaderContentRange       = "x-amz-fwd-header-Content-Range"
	AmzFwdHeaderContentType        = "x-amz-fwd-header-Content-Type"
	AmzFwdHeaderChecksumCrc32      = "x-amz-fwd-header-x-amz-checksum-crc32"
	AmzFwdHeaderChecksumCrc32c     = "x-amz-fwd-header-x-amz-checksum-crc32c"
	AmzFwdHeaderChecksumSha1       = "x-amz-fwd-header-x-amz-checksum-sha1"
	AmzFwdHeaderChecksumSha256     = "x-amz-fwd-header-x-amz-checksum-sha256"

		ETag:           partInfo.ETag,
		LastModified:   partInfo.ModTime,
		Size:           partInfo.Size,
		ActualSize:     partInfo.ActualSize,
		ChecksumCRC32:  partInfo.Checksums["CRC32"],
		ChecksumCRC32C: partInfo.Checksums["CRC32C"],
		ChecksumSHA1:   partInfo.Checksums["SHA1"],
		ChecksumSHA256: partInfo.Checksums["SHA256"],
	}, nil
}