org.apache.datasketches.hash

Class XxHash

java.lang.Object

org.apache.datasketches.hash.XxHash

public class XxHash
extends Object

The XxHash is a fast, non-cryptographic, 64-bit hash function that has excellent avalanche and 2-way bit independence properties. This java version used the C++ version and the OpenHFT/Zero-Allocation-Hashing implementation referenced below as inspiration.

The C++ source repository: https://github.com/Cyan4973/xxHash. It has a BSD 2-Clause License: http://www.opensource.org/licenses/bsd-license.php See LICENSE.

Portions of this code were adapted from OpenHFT/Zero-Allocation-Hashing, which has an Apache 2 license as does this site. See LICENSE.

Author:

Lee Rhodes

Constructor Summary

Constructors

Constructor and Description
XxHash()

Method Summary

Modifier and Type	Method and Description
static long	hash(long in, long seed) Returns a 64-bit hash.
static long	hash(org.apache.datasketches.memory.Memory mem, long offsetBytes, long lengthBytes, long seed) Compute the hash of the given Memory object.

Methods inherited from class java.lang.Object

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

Constructor Detail

XxHash

public XxHash()

Method Detail

hash

public static long hash(org.apache.datasketches.memory.Memory mem,
                        long offsetBytes,
                        long lengthBytes,
                        long seed)

Compute the hash of the given Memory object.

Parameters:

mem - The given Memory object

offsetBytes - Starting at this offset in bytes

lengthBytes - Continuing for this number of bytes

seed - use this seed for the hash function

Returns:

return the resulting 64-bit hash value.

hash

public static long hash(long in,
                        long seed)

Returns a 64-bit hash.

Parameters:

in - a long

seed - A long valued seed.

Returns:

the hash