content: package au.csiro.variantspark.utils;
  
  import com.google.common.primitives.Ints;
  import com.google.common.primitives.Longs;
  
  /**
   * A helper class for fast MumMur3 calculation with changing seed based directly on 
   * [[com.google.common.hash.Murmur3_32HashFunction]] (from guava)
   */
  public final class MurMur3Hash {
  	private static final int C1 = 0xcc9e2d51;
  	private static final int C2 = 0x1b873593;
  
  	public static int hashInt(int input, int seed) {
  		int k1 = mixK1(input);
  		int h1 = mixH1(seed, k1);
  
  		return fmix(h1, Ints.BYTES);
  	}
  
  	public static int hashLong(long input, int seed) {
  		int low = (int) input;
  		int high = (int) (input >>> 32);
  
  		int k1 = mixK1(low);
  		int h1 = mixH1(seed, k1);
  
  		k1 = mixK1(high);
  		h1 = mixH1(h1, k1);
  
  		return fmix(h1, Longs.BYTES);
  	}
  
  	private static int mixK1(int k1) {
  		k1 *= C1;
  		k1 = Integer.rotateLeft(k1, 15);
  		k1 *= C2;
  		return k1;
  	}
  
  	private static int mixH1(int h1, int k1) {
  		h1 ^= k1;
  		h1 = Integer.rotateLeft(h1, 13);
  		h1 = h1 * 5 + 0xe6546b64;
  		return h1;
  	}
  
  	// Finalization mix - force all bits of a hash block to avalanche
  	private static int fmix(int h1, int length) {
  		h1 ^= length;
  		h1 ^= h1 >>> 16;
  		h1 *= 0x85ebca6b;
  		h1 ^= h1 >>> 13;
  		h1 *= 0xc2b2ae35;
  		h1 ^= h1 >>> 16;
  		return h1;
  	}
  }