public static int murmurhash3_x86_32()

in java/fury-core/src/main/java/org/apache/fury/util/MurmurHash3.java [125:229]

• 68 lines of code
• 9 McCabe index (conditional complexity)

  public static int murmurhash3_x86_32(CharSequence data, int offset, int len, int seed) {

    final int c1 = 0xcc9e2d51;
    final int c2 = 0x1b873593;

    int h1 = seed;

    int pos = offset;
    int end = offset + len;
    int k1 = 0;
    int k2 = 0;
    int shift = 0;
    int bits = 0;
    int nBytes = 0; // length in UTF8 bytes

    while (pos < end) {
      int code = data.charAt(pos++);
      if (code < 0x80) {
        k2 = code;
        bits = 8;

        /**
         * * // optimized ascii implementation (currently slower!!! code size?) if (shift == 24) {
         * k1 = k1 | (code << 24);
         *
         * <p>k1 *= c1; k1 = (k1 << 15) | (k1 >>> 17); // ROTL32(k1,15); k1 *= c2;
         *
         * <p>h1 ^= k1; h1 = (h1 << 13) | (h1 >>> 19); // ROTL32(h1,13); h1 = h1*5+0xe6546b64;
         *
         * <p>shift = 0; nBytes += 4; k1 = 0; } else { k1 |= code << shift; shift += 8; } continue;
         * *
         */
      } else if (code < 0x800) {
        k2 = (0xC0 | (code >> 6)) | ((0x80 | (code & 0x3F)) << 8);
        bits = 16;
      } else if (code < 0xD800 || code > 0xDFFF || pos >= end) {
        // we check for pos>=end to encode an unpaired surrogate as 3 bytes.
        k2 =
            (0xE0 | (code >> 12))
                | ((0x80 | ((code >> 6) & 0x3F)) << 8)
                | ((0x80 | (code & 0x3F)) << 16);
        bits = 24;
      } else {
        // surrogate pair
        // int utf32 = pos < end ? (int) data.charAt(pos++) : 0;
        int utf32 = (int) data.charAt(pos++);
        utf32 = ((code - 0xD7C0) << 10) + (utf32 & 0x3FF);
        k2 =
            (0xff & (0xF0 | (utf32 >> 18)))
                | ((0x80 | ((utf32 >> 12) & 0x3F))) << 8
                | ((0x80 | ((utf32 >> 6) & 0x3F))) << 16
                | (0x80 | (utf32 & 0x3F)) << 24;
        bits = 32;
      }

      k1 |= k2 << shift;

      // int used_bits = 32 - shift;  // how many bits of k2 were used in k1.
      // int unused_bits = bits - used_bits; //  (bits-(32-shift)) == bits+shift-32  ==
      // bits-newshift

      shift += bits;
      if (shift >= 32) {
        // mix after we have a complete word

        k1 *= c1;
        k1 = (k1 << 15) | (k1 >>> 17); // ROTL32(k1,15);
        k1 *= c2;

        h1 ^= k1;
        h1 = (h1 << 13) | (h1 >>> 19); // ROTL32(h1,13);
        h1 = h1 * 5 + 0xe6546b64;

        shift -= 32;
        // unfortunately, java won't let you shift 32 bits off, so we need to check for 0
        if (shift != 0) {
          k1 = k2 >>> (bits - shift); // bits used == bits - newshift
        } else {
          k1 = 0;
        }
        nBytes += 4;
      }
    } // inner

    // handle tail
    if (shift > 0) {
      nBytes += shift >> 3;
      k1 *= c1;
      k1 = (k1 << 15) | (k1 >>> 17); // ROTL32(k1,15);
      k1 *= c2;
      h1 ^= k1;
    }

    // finalization
    h1 ^= nBytes;

    // fmix(h1);
    h1 ^= h1 >>> 16;
    h1 *= 0x85ebca6b;
    h1 ^= h1 >>> 13;
    h1 *= 0xc2b2ae35;
    h1 ^= h1 >>> 16;

    return h1;
  }