private long murmur()

in core/src/main/java/com/datastax/oss/driver/internal/core/metadata/token/Murmur3TokenFactory.java [73:187]

• 78 lines of code
• 17 McCabe index (conditional complexity)

  private long murmur(ByteBuffer data) {
    int offset = data.position();
    int length = data.remaining();

    int nblocks = length >> 4; // Process as 128-bit blocks.

    long h1 = 0;
    long h2 = 0;

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

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

    for (int i = 0; i < nblocks; i++) {
      long k1 = getblock(data, offset, i * 2);
      long k2 = getblock(data, 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) data.get(offset + 14)) << 48;
        // fall through
      case 14:
        k2 ^= ((long) data.get(offset + 13)) << 40;
        // fall through
      case 13:
        k2 ^= ((long) data.get(offset + 12)) << 32;
        // fall through
      case 12:
        k2 ^= ((long) data.get(offset + 11)) << 24;
        // fall through
      case 11:
        k2 ^= ((long) data.get(offset + 10)) << 16;
        // fall through
      case 10:
        k2 ^= ((long) data.get(offset + 9)) << 8;
        // fall through
      case 9:
        k2 ^= ((long) data.get(offset + 8));
        k2 *= c2;
        k2 = rotl64(k2, 33);
        k2 *= c1;
        h2 ^= k2;
        // fall through
      case 8:
        k1 ^= ((long) data.get(offset + 7)) << 56;
        // fall through
      case 7:
        k1 ^= ((long) data.get(offset + 6)) << 48;
        // fall through
      case 6:
        k1 ^= ((long) data.get(offset + 5)) << 40;
        // fall through
      case 5:
        k1 ^= ((long) data.get(offset + 4)) << 32;
        // fall through
      case 4:
        k1 ^= ((long) data.get(offset + 3)) << 24;
        // fall through
      case 3:
        k1 ^= ((long) data.get(offset + 2)) << 16;
        // fall through
      case 2:
        k1 ^= ((long) data.get(offset + 1)) << 8;
        // fall through
      case 1:
        k1 ^= ((long) data.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;

    return h1;
  }