scala.util.hashing

# MurmurHash3

#### object MurmurHash3 extends MurmurHash3

An implementation of Austin Appleby's MurmurHash 3 algorithm (MurmurHash3_x86_32). This object contains methods that hash values of various types as well as means to construct `Hashing` objects.

This algorithm is designed to generate well-distributed non-cryptographic hashes. It is designed to hash data in 32 bit chunks (ints).

The mix method needs to be called at each step to update the intermediate hash value. For the last chunk to incorporate into the hash mixLast may be used instead, which is slightly faster. Finally finalizeHash needs to be called to compute the final hash value.

This is based on the earlier MurmurHash3 code by Rex Kerr, but the MurmurHash3 algorithm was since changed by its creator Austin Appleby to remedy some weaknesses and improve performance. This represents the latest and supposedly final version of the algortihm (revision 136).

See also

  http://code.google.com/p/smhasher

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### Type Members

1. #### class ArrayHashing[T] extends Hashing[Array[T]]

### Value Members

1. #### final def !=(arg0: Any): Boolean

   Definition Classes
     AnyRef → Any

2. #### final def ##(): Int

   Definition Classes
     AnyRef → Any

3. #### final def ==(arg0: Any): Boolean

   Definition Classes
     AnyRef → Any

4. #### def arrayHash[T](a: Array[T]): Int

5. #### final def arrayHash[T](a: Array[T], seed: Int): Int

   Compute the hash of an array.

   Compute the hash of an array.

   Definition Classes
     MurmurHash3

6. #### def arrayHashing[T]: ArrayHashing[T]

7. #### final val arraySeed: Int(1007110753)

8. #### final def asInstanceOf[T0]: T0

   Definition Classes
     Any

9. #### def bytesHash(data: Array[Byte]): Int

10. #### final def bytesHash(data: Array[Byte], seed: Int): Int

    Compute the hash of a byte array.

    Compute the hash of a byte array. Faster than arrayHash, because it hashes 4 bytes at once.

    Definition Classes
      MurmurHash3

11. #### def bytesHashing: Hashing[Array[Byte]]

12. #### def clone(): AnyRef

    Attributes
      protected[java.lang]
    Definition Classes
      AnyRef
    Annotations
      @throws( ... )

13. #### final def eq(arg0: AnyRef): Boolean

    Definition Classes
      AnyRef

14. #### def equals(arg0: Any): Boolean

    Definition Classes
      AnyRef → Any

15. #### def finalize(): Unit

    Attributes
      protected[java.lang]
    Definition Classes
      AnyRef
    Annotations
      @throws( classOf[java.lang.Throwable] )

16. #### final def finalizeHash(hash: Int, length: Int): Int

    Finalize a hash to incorporate the length and make sure all bits avalanche.

    Finalize a hash to incorporate the length and make sure all bits avalanche.

    Definition Classes
      MurmurHash3

17. #### final def getClass(): Class[_]

    Definition Classes
      AnyRef → Any

18. #### def hashCode(): Int

    Definition Classes
      AnyRef → Any

19. #### final def isInstanceOf[T0]: Boolean

    Definition Classes
      Any

20. #### final def listHash(xs: collection.immutable.List[_], seed: Int): Int

    Definition Classes
      MurmurHash3

21. #### def mapHash(xs: Map[_, _]): Int

22. #### final val mapSeed: Int

23. #### final def mix(hash: Int, data: Int): Int

    Mix in a block of data into an intermediate hash value.

    Mix in a block of data into an intermediate hash value.

    Definition Classes
      MurmurHash3

24. #### final def mixLast(hash: Int, data: Int): Int

    May optionally be used as the last mixing step.

    May optionally be used as the last mixing step. Is a little bit faster than mix, as it does no further mixing of the resulting hash. For the last element this is not necessary as the hash is thoroughly mixed during finalization anyway.

    Definition Classes
      MurmurHash3

25. #### final def ne(arg0: AnyRef): Boolean

    Definition Classes
      AnyRef

26. #### final def notify(): Unit

    Definition Classes
      AnyRef

27. #### final def notifyAll(): Unit

    Definition Classes
      AnyRef

28. #### def orderedHash(xs: TraversableOnce[Any]): Int

29. #### final def orderedHash(xs: TraversableOnce[Any], seed: Int): Int

    Compute a hash that depends on the order of its arguments.

    Compute a hash that depends on the order of its arguments.

    Definition Classes
      MurmurHash3

30. #### def orderedHashing: Hashing[TraversableOnce[Any]]

31. #### def productHash(x: Product): Int

32. #### final def productHash(x: Product, seed: Int): Int

    Compute the hash of a product

    Compute the hash of a product

    Definition Classes
      MurmurHash3

33. #### def productHashing: Hashing[Product]

34. #### final val productSeed: Int(-889275714)

35. #### def seqHash(xs: collection.Seq[_]): Int

    To offer some potential for optimization.

36. #### final val seqSeed: Int

37. #### def setHash(xs: Set[_]): Int

38. #### final val setSeed: Int

39. #### def stringHash(x: String): Int

40. #### final def stringHash(str: String, seed: Int): Int

    Compute the hash of a string

    Compute the hash of a string

    Definition Classes
      MurmurHash3

41. #### def stringHashing: Hashing[String]

42. #### final val stringSeed: Int(-137723950)

43. #### final val symmetricSeed: Int(-1248659538)

44. #### final def synchronized[T0](arg0: ⇒ T0): T0

    Definition Classes
      AnyRef

45. #### def toString(): String

    Definition Classes
      AnyRef → Any

46. #### final val traversableSeed: Int(-415593707)

47. #### def unorderedHash(xs: TraversableOnce[Any]): Int

48. #### final def unorderedHash(xs: TraversableOnce[Any], seed: Int): Int

    Compute a hash that is symmetric in its arguments - that is a hash where the order of appearance of elements does not matter.

    Compute a hash that is symmetric in its arguments - that is a hash where the order of appearance of elements does not matter. This is useful for hashing sets, for example.

    Definition Classes
      MurmurHash3

49. #### def unorderedHashing: Hashing[TraversableOnce[Any]]

50. #### final def wait(): Unit

    Definition Classes
      AnyRef
    Annotations
      @throws( ... )

51. #### final def wait(arg0: Long, arg1: Int): Unit

    Definition Classes
      AnyRef
    Annotations
      @throws( ... )

52. #### final def wait(arg0: Long): Unit

    Definition Classes
      AnyRef
    Annotations
      @throws( ... )

### Inherited from MurmurHash3

### Inherited from AnyRef

### Inherited from Any

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