gnu.crypto.prng
Class BasePRNGStandalone

java.lang.Object
  extended by gnu.crypto.prng.BasePRNGStandalone
All Implemented Interfaces:
IRandomStandalone, java.lang.Cloneable
Direct Known Subclasses:
FortunaStandalone, FortunaStandalone.Generator

public abstract class BasePRNGStandalone
extends java.lang.Object
implements IRandomStandalone

An abstract class to facilitate implementing PRNG algorithms.

Modified slightly by jrandom for I2P (removing unneeded exceptions)

Version:
$Revision: 1.1 $

Field Summary
protected  byte[] buffer
          A temporary buffer to serve random bytes.
protected  boolean initialised
          Indicate if this instance has already been initialised or not.
protected  java.lang.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
protected BasePRNGStandalone(java.lang.String name)
          Trivial constructor for use by concrete subclasses.
 
Method Summary
 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.
 java.lang.Object clone()
          Returns a clone copy of this instance.
abstract  void fillBlock()
           
 void init(java.util.Map attributes)
          Initialises the pseudo-random number generator scheme with the appropriate attributes.
 boolean isInitialised()
           
 java.lang.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(java.util.Map attributes)
           
 
Methods inherited from class java.lang.Object
equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

name

protected java.lang.String name
The canonical name prefix of the PRNG algorithm.


initialised

protected boolean initialised
Indicate if this instance has already been initialised or not.


buffer

protected 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(java.lang.String name)

Trivial constructor for use by concrete subclasses.

Parameters:
name - the canonical name of this instance.
Method Detail

name

public java.lang.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(java.util.Map 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 java.lang.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:
java.lang.IllegalStateException - if the instance is not yet initialised.

nextBytes

public void nextBytes(byte[] out)
               throws java.lang.IllegalStateException
Throws:
java.lang.IllegalStateException

nextBytes

public void nextBytes(byte[] out,
                      int offset,
                      int length)
               throws java.lang.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:
java.lang.IllegalStateException - if the instance is not yet initialised.

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 java.lang.Object clone()
                       throws java.lang.CloneNotSupportedException
Description copied from interface: IRandomStandalone

Returns a clone copy of this instance.

Specified by:
clone in interface IRandomStandalone
Overrides:
clone in class java.lang.Object
Returns:
a clone copy of this instance.
Throws:
java.lang.CloneNotSupportedException

setup

public abstract void setup(java.util.Map attributes)

fillBlock

public abstract void fillBlock()