content: /*
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package io.airlift.slice;
  
  import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
  
  public final class Murmur3Hash128
  {
      private static final long C1 = 0x87c37b91114253d5L;
      private static final long C2 = 0x4cf5ad432745937fL;
  
      private static final long DEFAULT_SEED = 0;
  
      private Murmur3Hash128() {}
  
      public static Slice hash(Slice data)
      {
          return hash(data, 0, data.length());
      }
  
      public static Slice hash(Slice data, int offset, int length)
      {
          return hash(DEFAULT_SEED, data, offset, length);
      }
  
      @SuppressFBWarnings("SF_SWITCH_NO_DEFAULT")
      public static Slice hash(long seed, Slice data, int offset, int length)
      {
          final int fastLimit = offset + length - (2 * SizeOf.SIZE_OF_LONG) + 1;
  
          long h1 = seed;
          long h2 = seed;
  
          int current = offset;
          while (current < fastLimit) {
              long k1 = data.getLong(current);
              current += SizeOf.SIZE_OF_LONG;
  
              long k2 = data.getLong(current);
              current += SizeOf.SIZE_OF_LONG;
  
              k1 *= C1;
              k1 = Long.rotateLeft(k1, 31);
              k1 *= C2;
              h1 ^= k1;
  
              h1 = Long.rotateLeft(h1, 27);
              h1 += h2;
              h1 = h1 * 5 + 0x52dce729L;
  
              k2 *= C2;
              k2 = Long.rotateLeft(k2, 33);
              k2 *= C1;
              h2 ^= k2;
  
              h2 = Long.rotateLeft(h2, 31);
              h2 += h1;
              h2 = h2 * 5 + 0x38495ab5L;
          }
  
          long k1 = 0;
          long k2 = 0;
  
          switch (length & 15) {
              case 15:
                  k2 ^= ((long) data.getUnsignedByte(current + 14)) << 48;
              case 14:
                  k2 ^= ((long) data.getUnsignedByte(current + 13)) << 40;
              case 13:
                  k2 ^= ((long) data.getUnsignedByte(current + 12)) << 32;
              case 12:
                  k2 ^= ((long) data.getUnsignedByte(current + 11)) << 24;
              case 11:
                  k2 ^= ((long) data.getUnsignedByte(current + 10)) << 16;
              case 10:
                  k2 ^= ((long) data.getUnsignedByte(current + 9)) << 8;
              case 9:
                  k2 ^= ((long) data.getUnsignedByte(current + 8)) << 0;
  
                  k2 *= C2;
                  k2 = Long.rotateLeft(k2, 33);
                  k2 *= C1;
                  h2 ^= k2;
  
              case 8:
                  k1 ^= ((long) data.getUnsignedByte(current + 7)) << 56;
              case 7:
                  k1 ^= ((long) data.getUnsignedByte(current + 6)) << 48;
              case 6:
                  k1 ^= ((long) data.getUnsignedByte(current + 5)) << 40;
              case 5:
                  k1 ^= ((long) data.getUnsignedByte(current + 4)) << 32;
              case 4:
                  k1 ^= ((long) data.getUnsignedByte(current + 3)) << 24;
              case 3:
                  k1 ^= ((long) data.getUnsignedByte(current + 2)) << 16;
              case 2:
                  k1 ^= ((long) data.getUnsignedByte(current + 1)) << 8;
              case 1:
                  k1 ^= ((long) data.getUnsignedByte(current + 0)) << 0;
  
                  k1 *= C1;
                  k1 = Long.rotateLeft(k1, 31);
                  k1 *= C2;
                  h1 ^= k1;
          }
  
          h1 ^= length;
          h2 ^= length;
  
          h1 += h2;
          h2 += h1;
  
          h1 = mix64(h1);
          h2 = mix64(h2);
  
          h1 += h2;
          h2 += h1;
  
          Slice result = Slices.allocate(16);
          result.setLong(0, h1);
          result.setLong(8, h2);
  
          return result;
      }
  
      /**
       * Returns the 64 most significant bits of the Murmur128 hash of the provided value
       */
      public static long hash64(Slice data)
      {
          return hash64(data, 0, data.length());
      }
  
      public static long hash64(Slice data, int offset, int length)
      {
          return hash64(DEFAULT_SEED, data, offset, length);
      }
  
      @SuppressFBWarnings({"SF_SWITCH_NO_DEFAULT", "SF_SWITCH_FALLTHROUGH"})
      public static long hash64(long seed, Slice data, int offset, int length)
      {
          final int fastLimit = offset + length - (2 * SizeOf.SIZE_OF_LONG) + 1;
  
          long h1 = seed;
          long h2 = seed;
  
          int current = offset;
          while (current < fastLimit) {
              long k1 = data.getLong(current);
              current += SizeOf.SIZE_OF_LONG;
  
              long k2 = data.getLong(current);
              current += SizeOf.SIZE_OF_LONG;
  
              k1 *= C1;
              k1 = Long.rotateLeft(k1, 31);
              k1 *= C2;
              h1 ^= k1;
  
              h1 = Long.rotateLeft(h1, 27);
              h1 += h2;
              h1 = h1 * 5 + 0x52dce729L;
  
              k2 *= C2;
              k2 = Long.rotateLeft(k2, 33);
              k2 *= C1;
              h2 ^= k2;
  
              h2 = Long.rotateLeft(h2, 31);
              h2 += h1;
              h2 = h2 * 5 + 0x38495ab5L;
          }
  
          long k1 = 0;
          long k2 = 0;
  
          switch (length & 15) {
              case 15:
                  k2 ^= ((long) data.getUnsignedByte(current + 14)) << 48;
              case 14:
                  k2 ^= ((long) data.getUnsignedByte(current + 13)) << 40;
              case 13:
                  k2 ^= ((long) data.getUnsignedByte(current + 12)) << 32;
              case 12:
                  k2 ^= ((long) data.getUnsignedByte(current + 11)) << 24;
              case 11:
                  k2 ^= ((long) data.getUnsignedByte(current + 10)) << 16;
              case 10:
                  k2 ^= ((long) data.getUnsignedByte(current + 9)) << 8;
              case 9:
                  k2 ^= ((long) data.getUnsignedByte(current + 8)) << 0;
  
                  k2 *= C2;
                  k2 = Long.rotateLeft(k2, 33);
                  k2 *= C1;
                  h2 ^= k2;
  
              case 8:
                  k1 ^= ((long) data.getUnsignedByte(current + 7)) << 56;
              case 7:
                  k1 ^= ((long) data.getUnsignedByte(current + 6)) << 48;
              case 6:
                  k1 ^= ((long) data.getUnsignedByte(current + 5)) << 40;
              case 5:
                  k1 ^= ((long) data.getUnsignedByte(current + 4)) << 32;
              case 4:
                  k1 ^= ((long) data.getUnsignedByte(current + 3)) << 24;
              case 3:
                  k1 ^= ((long) data.getUnsignedByte(current + 2)) << 16;
              case 2:
                  k1 ^= ((long) data.getUnsignedByte(current + 1)) << 8;
              case 1:
                  k1 ^= ((long) data.getUnsignedByte(current + 0)) << 0;
  
                  k1 *= C1;
                  k1 = Long.rotateLeft(k1, 31);
                  k1 *= C2;
                  h1 ^= k1;
          }
  
          h1 ^= length;
          h2 ^= length;
  
          h1 += h2;
          h2 += h1;
  
          h1 = mix64(h1);
          h2 = mix64(h2);
  
          return h1 + h2;
      }
  
      /**
       * Special-purpose version for hashing a single long value. Value is treated as little-endian
       */
      public static long hash64(long value)
      {
          long h2 = DEFAULT_SEED ^ SizeOf.SIZE_OF_LONG;
          long h1 = h2 + (h2 ^ (Long.rotateLeft(value * C1, 31) * C2));
  
          return mix64(h1) + mix64(h1 + h2);
      }
  
      private static long mix64(long k)
      {
          k ^= k >>> 33;
          k *= 0xff51afd7ed558ccdL;
          k ^= k >>> 33;
          k *= 0xc4ceb9fe1a85ec53L;
          k ^= k >>> 33;
  
          return k;
      }
  }
  