public static long[] hash3_x64_128(ByteBuffer key, int offset, int length, long seed) {
    final int nblocks = length >> 4; // Process as 128-bit blocks.

    long h1 = seed;
    long h2 = seed;

    long c1 = 0x87c37b91114253d5L;
    long c2 = 0x4cf5ad432745937fL;

    //----------
    // body

    for (int i = 0; i < nblocks; i++) {
      long k1 = getblock(key, offset, i * 2 + 0);
      long k2 = getblock(key, offset, i * 2 + 1);

      k1 *= c1;
      k1 = rotl64(k1, 31);
      k1 *= c2;
      h1 ^= k1;

      h1 = rotl64(h1, 27);
      h1 += h2;
      h1 = h1 * 5 + 0x52dce729;

      k2 *= c2;
      k2 = rotl64(k2, 33);
      k2 *= c1;
      h2 ^= k2;

      h2 = rotl64(h2, 31);
      h2 += h1;
      h2 = h2 * 5 + 0x38495ab5;
    }

    //----------
    // tail

    // Advance offset to the unprocessed tail of the data.
    offset += nblocks * 16;

    long k1 = 0;
    long k2 = 0;

    switch (length & 15) {
      case 15:
        k2 ^= ((long) key.get(offset + 14)) << 48;
      case 14:
        k2 ^= ((long) key.get(offset + 13)) << 40;
      case 13:
        k2 ^= ((long) key.get(offset + 12)) << 32;
      case 12:
        k2 ^= ((long) key.get(offset + 11)) << 24;
      case 11:
        k2 ^= ((long) key.get(offset + 10)) << 16;
      case 10:
        k2 ^= ((long) key.get(offset + 9)) << 8;
      case 9:
        k2 ^= ((long) key.get(offset + 8)) << 0;
        k2 *= c2;
        k2 = rotl64(k2, 33);
        k2 *= c1;
        h2 ^= k2;

      case 8:
        k1 ^= ((long) key.get(offset + 7)) << 56;
      case 7:
        k1 ^= ((long) key.get(offset + 6)) << 48;
      case 6:
        k1 ^= ((long) key.get(offset + 5)) << 40;
      case 5:
        k1 ^= ((long) key.get(offset + 4)) << 32;
      case 4:
        k1 ^= ((long) key.get(offset + 3)) << 24;
      case 3:
        k1 ^= ((long) key.get(offset + 2)) << 16;
      case 2:
        k1 ^= ((long) key.get(offset + 1)) << 8;
      case 1:
        k1 ^= ((long) key.get(offset));
        k1 *= c1;
        k1 = rotl64(k1, 31);
        k1 *= c2;
        h1 ^= k1;
    }
    ;

    //----------
    // finalization

    h1 ^= length;
    h2 ^= length;

    h1 += h2;
    h2 += h1;

    h1 = fmix(h1);
    h2 = fmix(h2);

    h1 += h2;
    h2 += h1;

    return (new long[]{h1, h2});
  }
This is a very fast, non-cryptographic hash suitable for general hash-based
lookup. See http://murmurhash.googlepages.com/ for more details.

hash32() and hash64() are MurmurHash 2.0.
hash3_x64_128() is MurmurHash 3.0.

<p>
The C version of MurmurHash 2.0 found at that site was ported to Java by
Andrzej Bialecki (ab at getopt org).
</p>
ambry-utils/src/main/java/com/github/ambry/utils/MurmurHash.java