## gnu.crypto.prng
Class BasePRNGStandalone

    java.lang.Object
      gnu.crypto.prng.BasePRNGStandalone

All Implemented Interfaces:
  IRandomStandalone, Cloneable

Direct Known Subclasses:
  FortunaStandalone, FortunaStandalone.Generator

    public abstract class BasePRNGStandalone

extends 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 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(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.
`Object` `clone()` Returns a clone copy of this instance.
`abstract void` `fillBlock()`
`void` `init(Map 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 attributes)`

Methods inherited from class java.lang.Object
`equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Field Detail

### name

    protected 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(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 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.

### 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.

### 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 attributes)

### fillBlock

    public abstract void fillBlock()