de.greenrobot.common.hash

Class FNVJ32

java.lang.Object

de.greenrobot.common.hash.FNVJ32

All Implemented Interfaces:

Checksum

public class FNVJ32
extends Object
implements Checksum

Custom 32-bit hash function favoring speed over quality. Tests with random data showed pretty good collision behaviour, although quality measured by SMHasher is pretty bad (much worse than FNV).

If you do progressive updates, update with byte lengths that are a multiple of 4 for best performance.

Based on FNV, but xors 4 bytes at once after each multiplication.

Constructor Summary

Constructors

Constructor and Description
FNVJ32()
FNVJ32(int seed)

Method Summary

Methods

Modifier and Type	Method and Description
int	getLength()
long	getValue()
void	reset()
void	update(byte[] b, int off, int len)
void	update(int b)

Methods inherited from class java.lang.Object

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

Constructor Detail

FNVJ32

public FNVJ32()

FNVJ32

public FNVJ32(int seed)

Method Detail

update

public void update(int b)

Specified by:

update in interface Checksum

update

public void update(byte[] b,
          int off,
          int len)

Specified by:

update in interface Checksum

getValue

public long getValue()

Specified by:

getValue in interface Checksum

reset

public void reset()

Specified by:

reset in interface Checksum

getLength

public int getLength()