org.apache.commons.codec.digest

Class MurmurHash2

java.lang.Object

org.apache.commons.codec.digest.MurmurHash2

public final class MurmurHash2
extends Object

MurmurHash2 yields a 32-bit or 64-bit value. MurmurHash is a non-cryptographic hash function suitable for general hash-based lookup. The name comes from two basic operations, multiply (MU) and rotate (R), used in its inner loop. Unlike cryptographic hash functions, it is not specifically designed to be difficult to reverse by an adversary, making it unsuitable for cryptographic purposes. This is a re-implementation of the original C code plus some additional features. Public domain.

Since:

1.13

See Also:

MurmurHash

Method Summary

Modifier and Type	Method and Description
static int	hash32(byte[] data, int length) Generates 32 bit hash from byte array with default seed value.
static int	hash32(byte[] data, int length, int seed) Generates 32 bit hash from byte array of the given length and seed.
static int	hash32(String text) Generates 32 bit hash from a string.
static int	hash32(String text, int from, int length) Generates 32 bit hash from a substring.
static long	hash64(byte[] data, int length) Generates 64 bit hash from byte array with default seed value.
static long	hash64(byte[] data, int length, int seed) Generates 64 bit hash from byte array of the given length and seed.
static long	hash64(String text) Generates 64 bit hash from a string.
static long	hash64(String text, int from, int length) Generates 64 bit hash from a substring.

Methods inherited from class java.lang.Object

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

Method Detail

hash32

public static int hash32(byte[] data,
                         int length,
                         int seed)

Generates 32 bit hash from byte array of the given length and seed.

Parameters:

data - byte array to hash

length - length of the array to hash

seed - initial seed value

Returns:

32 bit hash of the given array

hash32

public static int hash32(byte[] data,
                         int length)

Generates 32 bit hash from byte array with default seed value.

Parameters:

data - byte array to hash

length - length of the array to hash

Returns:

32 bit hash of the given array

hash32

public static int hash32(String text)

Generates 32 bit hash from a string.

Parameters:

text - string to hash

Returns:

32 bit hash of the given string

hash32

public static int hash32(String text,
                         int from,
                         int length)

Generates 32 bit hash from a substring.

Parameters:

text - string to hash

from - starting index

length - length of the substring to hash

Returns:

32 bit hash of the given string

hash64

public static long hash64(byte[] data,
                          int length,
                          int seed)

Generates 64 bit hash from byte array of the given length and seed.

Parameters:

data - byte array to hash

length - length of the array to hash

seed - initial seed value

Returns:

64 bit hash of the given array

hash64

public static long hash64(byte[] data,
                          int length)

Generates 64 bit hash from byte array with default seed value.

Parameters:

data - byte array to hash

length - length of the array to hash

Returns:

64 bit hash of the given string

hash64

public static long hash64(String text)

Generates 64 bit hash from a string.

Parameters:

text - string to hash

Returns:

64 bit hash of the given string

hash64

public static long hash64(String text,
                          int from,
                          int length)

Generates 64 bit hash from a substring.

Parameters:

text - string to hash

from - starting index

length - length of the substring to hash

Returns:

64 bit hash of the given array