gnu.java.security.prng
Class BasePRNG
- Cloneable, IRandom
An abstract class to facilitate implementing PRNG algorithms.
protected byte[] | buffer - A temporary buffer to serve random bytes.
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protected boolean | initialised - Indicate if this instance has already been initialised or not.
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protected String | name - The canonical name prefix of the PRNG algorithm.
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protected int | ndx - The index into buffer of where the next byte will come from.
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BasePRNG(String name) - Trivial constructor for use by concrete subclasses.
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void | addRandomByte(byte b) - Supplement, or possibly replace, the random state of this PRNG with a
random byte.
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void | addRandomBytes(byte[] buffer) - Supplement, or possibly replace, the random state of this PRNG with a
sequence of new random bytes.
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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.
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Object | clone() - Returns a clone copy of this instance.
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abstract void | fillBlock()
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void | init(Map attributes) - Initialises the pseudo-random number generator scheme with the appropriate
attributes.
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boolean | isInitialised()
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String | name() - Returns the canonical name of this instance.
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byte | nextByte() - Returns the next 8 bits of random data generated from this instance.
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void | nextBytes(byte[] out)
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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.
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abstract void | setup(Map attributes)
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clone , equals , finalize , getClass , hashCode , notify , notifyAll , toString , wait , wait , wait |
buffer
protected byte[] buffer
A temporary buffer to serve random bytes.
initialised
protected boolean initialised
Indicate if this instance has already been initialised or not.
name
protected String name
The canonical name prefix of the PRNG algorithm.
ndx
protected int ndx
The index into buffer of where the next byte will come from.
BasePRNG
protected BasePRNG(String name)
Trivial constructor for use by concrete subclasses.
name
- the canonical name of this instance.
addRandomByte
public void addRandomByte(byte b)
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
.
- addRandomByte in interface IRandom
addRandomBytes
public void addRandomBytes(byte[] buffer)
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
.
- addRandomBytes in interface IRandom
addRandomBytes
public 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.
Implementations are not required to implement this method in any meaningful
way; this may be a no-operation, and implementations may throw an
UnsupportedOperationException
.
- addRandomBytes in interface IRandom
offset
- The offset from whence to begin reading random bytes.length
- The number of random bytes to add.
init
public void init(Map attributes)
Initialises the pseudo-random number generator scheme with the appropriate
attributes.
- init in interface IRandom
attributes
- a set of name-value pairs that describe the desired
future instance behaviour.
name
public String name()
Returns the canonical name of this instance.
- name in interface IRandom
- the canonical name of this instance.
nextBytes
public void nextBytes(byte[] out,
int offset,
int length)
throws IllegalStateException,
LimitReachedException
Fills the designated byte array, starting from byte at index
offset
, for a maximum of length
bytes with
the output of this generator instance.
- nextBytes in interface IRandom
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
.
setup
public abstract void setup(Map attributes)
BasePRNG.java --
Copyright (C) 2001, 2002, 2006 Free Software Foundation, Inc.
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