org.infinispan.commons.hash

Class MurmurHash3

java.lang.Object

org.infinispan.commons.hash.MurmurHash3

All Implemented Interfaces:

Hash

@ThreadSafe
@Immutable
public class MurmurHash3
extends Object
implements Hash

MurmurHash3 implementation in Java, based on Austin Appleby's original in C Only implementing x64 version, because this should always be faster on 64 bit native processors, even 64 bit being ran with a 32 bit OS; this should also be as fast or faster than the x86 version on some modern 32 bit processors.

Since:

5.0

Author:

Patrick McFarland

See Also:

MurmurHash website, MurmurHash entry on Wikipedia

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	MurmurHash3.Externalizer

Constructor Summary

Constructors

Constructor and Description
MurmurHash3()

Method Summary

Methods

Modifier and Type	Method and Description
boolean	equals(Object other)
int	hash(byte[] payload) Hashes a byte array efficiently.
int	hash(int hashcode) An incremental version of the hash function, that spreads a pre-calculated hash code, such as one derived from Object.hashCode().
static int	hash(long[] payload) Hashes a byte array efficiently.
int	hash(Object o) A helper that calculates the hashcode of an object, choosing the optimal mechanism of hash calculation after considering the type of the object (byte array, String or Object).
static long[]	MurmurHash3_x64_128(byte[] key, int seed) Hash a value using the x64 128 bit variant of MurmurHash3
static long[]	MurmurHash3_x64_128(long[] key, int seed) Hash a value using the x64 128 bit variant of MurmurHash3
static int	MurmurHash3_x64_32(byte[] key, int seed) Hash a value using the x64 32 bit variant of MurmurHash3
static int	MurmurHash3_x64_32(long[] key, int seed) Hash a value using the x64 32 bit variant of MurmurHash3
static long	MurmurHash3_x64_64(byte[] key, int seed) Hash a value using the x64 64 bit variant of MurmurHash3
static long	MurmurHash3_x64_64(long[] key, int seed) Hash a value using the x64 64 bit variant of MurmurHash3
String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

MurmurHash3

public MurmurHash3()

Method Detail

MurmurHash3_x64_128

public static long[] MurmurHash3_x64_128(byte[] key,
                         int seed)

Hash a value using the x64 128 bit variant of MurmurHash3

Parameters:

key - value to hash

seed - random value

Returns:

128 bit hashed key, in an array containing two longs

MurmurHash3_x64_64

public static long MurmurHash3_x64_64(byte[] key,
                      int seed)

Hash a value using the x64 64 bit variant of MurmurHash3

Parameters:

key - value to hash

seed - random value

Returns:

64 bit hashed key

MurmurHash3_x64_32

public static int MurmurHash3_x64_32(byte[] key,
                     int seed)

Hash a value using the x64 32 bit variant of MurmurHash3

Parameters:

key - value to hash

seed - random value

Returns:

32 bit hashed key

MurmurHash3_x64_128

public static long[] MurmurHash3_x64_128(long[] key,
                         int seed)

Hash a value using the x64 128 bit variant of MurmurHash3

Parameters:

key - value to hash

seed - random value

Returns:

128 bit hashed key, in an array containing two longs

MurmurHash3_x64_64

public static long MurmurHash3_x64_64(long[] key,
                      int seed)

Hash a value using the x64 64 bit variant of MurmurHash3

Parameters:

key - value to hash

seed - random value

Returns:

64 bit hashed key

MurmurHash3_x64_32

public static int MurmurHash3_x64_32(long[] key,
                     int seed)

Hash a value using the x64 32 bit variant of MurmurHash3

Parameters:

key - value to hash

seed - random value

Returns:

32 bit hashed key

hash

public int hash(byte[] payload)

Description copied from interface: Hash

Hashes a byte array efficiently.

Specified by:

hash in interface Hash

Parameters:

payload - a byte array to hash

Returns:

a hash code for the byte array

hash

public static int hash(long[] payload)

Hashes a byte array efficiently.

Parameters:

payload - a byte array to hash

Returns:

a hash code for the byte array

hash

public int hash(int hashcode)

Description copied from interface: Hash

An incremental version of the hash function, that spreads a pre-calculated hash code, such as one derived from Object.hashCode().

Specified by:

hash in interface Hash

Parameters:

hashcode - an object's hashcode

Returns:

a spread and hashed version of the hashcode

hash

public int hash(Object o)

Description copied from interface: Hash

A helper that calculates the hashcode of an object, choosing the optimal mechanism of hash calculation after considering the type of the object (byte array, String or Object).

Specified by:

hash in interface Hash

Parameters:

o - object to hash

Returns:

a hashcode

equals

public boolean equals(Object other)

Overrides:

equals in class Object

toString

public String toString()

Overrides:

toString in class Object