text: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you 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 org.apache.hive.common.util;
  
  /*
   * Common hash code routines.
   */
  public class HashCodeUtil {
  
    public static int calculateIntHashCode(int key) {
      key = ~key + (key << 15); // key = (key << 15) - key - 1;
      key = key ^ (key >>> 12);
      key = key + (key << 2);
      key = key ^ (key >>> 4);
      key = key * 2057; // key = (key + (key << 3)) + (key << 11);
      key = key ^ (key >>> 16);
      return key;
    }
  
    public static int calculateTwoLongHashCode(long l0, long l1) {
      return Murmur3.hash32(l0, l1);
    }
  
    public static int calculateLongHashCode(long key) {
      return Murmur3.hash32(key);
    }
  
    public static void calculateLongArrayHashCodes(long[] longs, int[] hashCodes, final int count) {
      for (int v = 0; v < count; v++) {
        hashCodes[v] = (int) calculateLongHashCode(longs[v]);
      }
    }
  
    @Deprecated
    public static int calculateBytesHashCode(byte[] keyBytes, int keyStart, int keyLength) {
      // Don't use this for ReduceSinkOperators
      return murmurHash(keyBytes, keyStart, keyLength);
    }
  
    public static void calculateBytesArrayHashCodes(byte[][] bytesArrays,
        int[] starts, int[] lengths, int[] valueSelected, int[] hashCodes, final int count) {
  
      for (int i = 0; i < count; i++) {
        int batchIndex = valueSelected[i];
        hashCodes[i] = murmurHash(bytesArrays[batchIndex], starts[batchIndex],
            lengths[batchIndex]);
      }
    }
  
    // Lifted from org.apache.hadoop.util.hash.MurmurHash... but supports offset.
    // Must produce the same result as MurmurHash.hash with seed = 0.
    public static int murmurHash(byte[] data, int offset, int length) {
      int m = 0x5bd1e995;
      int r = 24;
  
      int h = length;
  
      int len_4 = length >> 2;
  
      for (int i = 0; i < len_4; i++) {
        int i_4 = offset + (i << 2);
        int k = data[i_4 + 3];
        k = k << 8;
        k = k | (data[i_4 + 2] & 0xff);
        k = k << 8;
        k = k | (data[i_4 + 1] & 0xff);
        k = k << 8;
        k = k | (data[i_4 + 0] & 0xff);
        k *= m;
        k ^= k >>> r;
        k *= m;
        h *= m;
        h ^= k;
      }
  
      // avoid calculating modulo
      int len_m = len_4 << 2;
      int left = length - len_m;
  
      if (left != 0) {
        length += offset;
        if (left >= 3) {
          h ^= (int) data[length - 3] << 16;
        }
        if (left >= 2) {
          h ^= (int) data[length - 2] << 8;
        }
        if (left >= 1) {
          h ^= (int) data[length - 1];
        }
  
        h *= m;
      }
  
      h ^= h >>> 13;
      h *= m;
      h ^= h >>> 15;
  
      return h;
    }
  }