Top Description Inners Fields Constructors Methods
com.google.common.hash

pack-priv final Class SipHashFunction

extends AbstractHashFunction
implements Serializable
Class Inheritance
All Implemented Interfaces
java.io.Serializable
Annotations
@Immutable
@ElementTypesAreNonnullByDefault
Static Imports
com.google.common.base.Preconditions.checkArgument

HashFunction implementation of SipHash-c-d.
Authors
Kurt Alfred Kluever, Jean-Philippe Aumasson, Daniel J. Bernstein

Nested and Inner Type Summary

Modifier and TypeClass and Description
private static class

Field Summary

Modifier and TypeField and Description
private final int
c

private final int
d

private final long
private final long
private static final long
pack-priv static final HashFunction

Constructor Summary

AccessConstructor and Description
pack-priv
SipHashFunction(int
the number of compression rounds (must be positive)
c
,
int
the number of finalization rounds (must be positive)
d
,
long
the first half of the key
k0
,
long
the second half of the key
k1
)

Method Summary

Modifier and TypeMethod and Description
public int
bits()

Implements com.google.common.hash.HashFunction.bits.

Returns the number of bits (a multiple of 32) that each hash code produced by this hash function has.
public boolean
equals(Object
the reference object with which to compare.
object
)

Overrides java.lang.Object.equals.

Indicates whether some other object is "equal to" this one.
public int
hashCode()

Overrides java.lang.Object.hashCode.

Returns a hash code value for the object.
public Hasher
newHasher()

Implements com.google.common.hash.HashFunction.newHasher.

Begins a new hash code computation by returning an initialized, stateful Hasher instance that is ready to receive data.
public String
toString()

Overrides java.lang.Object.toString.

Returns a string representation of the object.
Inherited from com.google.common.hash.AbstractHashFunction:
hashByteshashByteshashByteshashInthashLonghashObjecthashStringhashUnencodedCharsnewHasher

Field Detail

cback to summary
private final int c
dback to summary
private final int d
k0back to summary
private final long k0
k1back to summary
private final long k1
serialVersionUIDback to summary
private static final long serialVersionUID
SIP_HASH_24back to summary
pack-priv static final HashFunction SIP_HASH_24

Constructor Detail

SipHashFunctionback to summary
pack-priv SipHashFunction(int c, int d, long k0, long k1)
Parameters
c:int

the number of compression rounds (must be positive)

d:int

the number of finalization rounds (must be positive)

k0:long

the first half of the key

k1:long

the second half of the key

Method Detail

bitsback to summary
public int bits()

Implements com.google.common.hash.HashFunction.bits.

Doc from com.google.common.hash.HashFunction.bits.

Returns the number of bits (a multiple of 32) that each hash code produced by this hash function has.

Annotations
@Override
equalsback to summary
public boolean equals(Object object)

Overrides java.lang.Object.equals.

Doc from java.lang.Object.equals.

Indicates whether some other object is "equal to" this one.

The equals method implements an equivalence relation on non-null object references:

  • It is reflexive: for any non-null reference value x, x.equals(x) should return true.
  • It is symmetric: for any non-null reference values x and y, x.equals(y) should return true if and only if y.equals(x) returns true.
  • It is transitive: for any non-null reference values x, y, and z, if x.equals(y) returns true and y.equals(z) returns true, then x.equals(z) should return true.
  • It is consistent: for any non-null reference values x and y, multiple invocations of x.equals(y) consistently return true or consistently return false, provided no information used in equals comparisons on the objects is modified.
  • For any non-null reference value x, x.equals(null) should return false.

An equivalence relation partitions the elements it operates on into equivalence classes; all the members of an equivalence class are equal to each other. Members of an equivalence class are substitutable for each other, at least for some purposes.

Parameters
object:Object

the reference object with which to compare.

Returns:boolean

true if this object is the same as the obj argument; false otherwise.

Annotations
@Override
hashCodeback to summary
public int hashCode()

Overrides java.lang.Object.hashCode.

Doc from java.lang.Object.hashCode.

Returns a hash code value for the object. This method is supported for the benefit of hash tables such as those provided by java.util.HashMap.

The general contract of hashCode is:

  • Whenever it is invoked on the same object more than once during an execution of a Java application, the hashCode method must consistently return the same integer, provided no information used in equals comparisons on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application.
  • If two objects are equal according to the equals method, then calling the hashCode method on each of the two objects must produce the same integer result.
  • It is not required that if two objects are unequal according to the equals method, then calling the hashCode method on each of the two objects must produce distinct integer results. However, the programmer should be aware that producing distinct integer results for unequal objects may improve the performance of hash tables.
Returns:int

a hash code value for this object.

Annotations
@Override
newHasherback to summary
public Hasher newHasher()

Implements com.google.common.hash.HashFunction.newHasher.

Doc from com.google.common.hash.HashFunction.newHasher.

Begins a new hash code computation by returning an initialized, stateful Hasher instance that is ready to receive data. Example:

HashFunction hf = Hashing.md5();
HashCode hc = hf.newHasher()
    .putLong(id)
    .putBoolean(isActive)
    .hash();
Annotations
@Override
toStringback to summary
public String toString()

Overrides java.lang.Object.toString.

Doc from java.lang.Object.toString.

Returns a string representation of the object.

Returns:String

a string representation of the object.

Annotations
@Override
com.google.common.hash back to summary

private final Class SipHashFunction.SipHasher

extends AbstractStreamingHasher
Class Inheritance

Field Summary

Modifier and TypeField and Description
private long
b

private final int
c

private static final int
private final int
d

private long
private long
private long
private long
private long

Constructor Summary

AccessConstructor and Description
pack-priv
SipHasher(int c, int d, long k0, long k1)

Method Summary

Modifier and TypeMethod and Description
protected HashCode
makeHash()

Implements abstract com.google.common.hash.AbstractStreamingHasher.makeHash.

Computes a hash code based on the data that have been provided to this hasher.
protected void
process(ByteBuffer buffer)

Implements abstract com.google.common.hash.AbstractStreamingHasher.process.

Processes the available bytes of the buffer (at most chunk bytes).
private void
processM(long m)

protected void
processRemaining(ByteBuffer buffer)

Overrides com.google.common.hash.AbstractStreamingHasher.processRemaining.

This is invoked for the last bytes of the input, which are not enough to fill a whole chunk.
private void
sipRound(int iterations)

Inherited from com.google.common.hash.AbstractStreamingHasher:
hashputByteputBytesputBytesputCharputIntputLongputShort

Field Detail

bback to summary
private long b
cback to summary
private final int c
CHUNK_SIZEback to summary
private static final int CHUNK_SIZE
dback to summary
private final int d
finalMback to summary
private long finalM
v0back to summary
private long v0
v1back to summary
private long v1
v2back to summary
private long v2
v3back to summary
private long v3

Constructor Detail

SipHasherback to summary
pack-priv SipHasher(int c, int d, long k0, long k1)

Method Detail

makeHashback to summary
protected HashCode makeHash()

Implements abstract com.google.common.hash.AbstractStreamingHasher.makeHash.

Doc from com.google.common.hash.AbstractStreamingHasher.makeHash.

Computes a hash code based on the data that have been provided to this hasher. This is called after all chunks are handled with process and any leftover bytes that did not make a complete chunk are handled with processRemaining.

Annotations
@Override
processback to summary
protected void process(ByteBuffer buffer)

Implements abstract com.google.common.hash.AbstractStreamingHasher.process.

Doc from com.google.common.hash.AbstractStreamingHasher.process.

Processes the available bytes of the buffer (at most chunk bytes).

Annotations
@Override
processMback to summary
private void processM(long m)
processRemainingback to summary
protected void processRemaining(ByteBuffer buffer)

Overrides com.google.common.hash.AbstractStreamingHasher.processRemaining.

Doc from com.google.common.hash.AbstractStreamingHasher.processRemaining.

This is invoked for the last bytes of the input, which are not enough to fill a whole chunk. The passed ByteBuffer is guaranteed to be non-empty.

This implementation simply pads with zeros and delegates to process(ByteBuffer).

Annotations
@Override
sipRoundback to summary
private void sipRound(int iterations)