Package gnu.crypto.prng

Class BasePRNGStandalone

java.lang.Object

gnu.crypto.prng.BasePRNGStandalone

All Implemented Interfaces:

IRandomStandalone, Serializable, Cloneable

Direct Known Subclasses:

FortunaStandalone, FortunaStandalone.Generator

public abstract class BasePRNGStandalone
extends Object
implements IRandomStandalone, Serializable

An abstract class to facilitate implementing PRNG algorithms.

Modified slightly by jrandom for I2P (removing unneeded exceptions)

Version:

$Revision: 1.1 $

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
protected byte[]	buffer	A temporary buffer to serve random bytes.
protected boolean	initialised	Indicate if this instance has already been initialised or not.
protected String	name	The canonical name prefix of the PRNG algorithm.
protected int	ndx	The index into buffer of where the next byte will come from.

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	BasePRNGStandalone(String name)	Trivial constructor for use by concrete subclasses.

Method Summary

Modifier and Type	Method	Description
void	addRandomByte(byte b)	Supplement, or possibly replace, the random state of this PRNG with a random byte.
void	addRandomBytes(byte[] buffer)	Supplement, or possibly replace, the random state of this PRNG with a sequence of new random bytes.
void	addRandomBytes(byte[] buffer, int offset, int length)	Supplement, or possibly replace, the random state of this PRNG with a sequence of new random bytes.
Object	clone()	Returns a clone copy of this instance.
abstract void	fillBlock()
void	init(Map<String,byte[]> attributes)	Initialises the pseudo-random number generator scheme with the appropriate attributes.
boolean	isInitialised()
String	name()	Returns the canonical name of this instance.
byte	nextByte()	Returns the next 8 bits of random data generated from this instance.
void	nextBytes(byte[] out)
void	nextBytes(byte[] out, int offset, int length)	Fills the designated byte array, starting from byte at index offset, for a maximum of length bytes with the output of this generator instance.
abstract void	setup(Map<String,byte[]> attributes)

Methods inherited from class java.lang.Object

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

Field Detail

name

protected final String name

The canonical name prefix of the PRNG algorithm.

initialised

protected volatile boolean initialised

Indicate if this instance has already been initialised or not.

buffer

protected volatile byte[] buffer

A temporary buffer to serve random bytes.

ndx

protected int ndx

The index into buffer of where the next byte will come from.

Constructor Detail

BasePRNGStandalone

protected BasePRNGStandalone(String name)

Trivial constructor for use by concrete subclasses.

Parameters:

name - the canonical name of this instance.

Method Detail

name

public String name()

Description copied from interface: IRandomStandalone

Returns the canonical name of this instance.

Specified by:

name in interface IRandomStandalone

Returns:

the canonical name of this instance.

init

public void init(Map<String,byte[]> attributes)

Description copied from interface: IRandomStandalone

Initialises the pseudo-random number generator scheme with the appropriate attributes.

Specified by:

init in interface IRandomStandalone

Parameters:

attributes - a set of name-value pairs that describe the desired future instance behaviour.

nextByte

public byte nextByte()
              throws IllegalStateException

Description copied from interface: IRandomStandalone

Returns the next 8 bits of random data generated from this instance.

Specified by:

nextByte in interface IRandomStandalone

Returns:

the next 8 bits of random data generated from this instance.

Throws:

IllegalStateException - if the instance is not yet initialised. theoretical limit for generating non-repetitive pseudo-random data.

nextBytes

public void nextBytes(byte[] out)
               throws IllegalStateException

Throws:

IllegalStateException

nextBytes

public void nextBytes(byte[] out,
                      int offset,
                      int length)
               throws IllegalStateException

Description copied from interface: IRandomStandalone

Fills the designated byte array, starting from byte at index offset, for a maximum of length bytes with the output of this generator instance.

Specified by:

nextBytes in interface IRandomStandalone

Parameters:

out - the placeholder to contain the generated random bytes.

offset - the starting index in out to consider. This method does nothing if this parameter is not within 0 and out.length.

length - the maximum number of required random bytes. This method does nothing if this parameter is less than 1.

Throws:

IllegalStateException - if the instance is not yet initialised. theoretical limit for generating non-repetitive pseudo-random data.

addRandomByte

public void addRandomByte(byte b)

Description copied from interface: IRandomStandalone

Supplement, or possibly replace, the random state of this PRNG with a random byte.

Implementations are not required to implement this method in any meaningful way; this may be a no-operation, and implementations may throw an UnsupportedOperationException.

Specified by:

addRandomByte in interface IRandomStandalone

Parameters:

b - The byte to add.

addRandomBytes

public void addRandomBytes(byte[] buffer)

Description copied from interface: IRandomStandalone

Supplement, or possibly replace, the random state of this PRNG with a sequence of new random bytes.

Implementations are not required to implement this method in any meaningful way; this may be a no-operation, and implementations may throw an UnsupportedOperationException.

Specified by:

addRandomBytes in interface IRandomStandalone

Parameters:

buffer - The buffer of new random bytes to add.

addRandomBytes

public void addRandomBytes(byte[] buffer,
                           int offset,
                           int length)

Description copied from interface: IRandomStandalone

Supplement, or possibly replace, the random state of this PRNG with a sequence of new random bytes.

Implementations are not required to implement this method in any meaningful way; this may be a no-operation, and implementations may throw an UnsupportedOperationException.

Specified by:

addRandomBytes in interface IRandomStandalone

Parameters:

buffer - The buffer of new random bytes to add.

offset - The offset from whence to begin reading random bytes.

length - The number of random bytes to add.

isInitialised

public boolean isInitialised()

clone

public Object clone()
             throws CloneNotSupportedException

Description copied from interface: IRandomStandalone

Returns a clone copy of this instance.

Specified by:

clone in interface IRandomStandalone

Overrides:

clone in class Object

Returns:

a clone copy of this instance.

Throws:

CloneNotSupportedException

setup

public abstract void setup(Map<String,byte[]> attributes)

fillBlock

public abstract void fillBlock()