gnu.crypto.prng
Class BasePRNG
- Cloneable, IRandom
public abstract class BasePRNG
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.
Implementations are not required to implement this method in any
meaningful way; this may be a no-operation, and implementations may
throw an
UnsupportedOperationException .
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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.
Implementations are not required to implement this method in any
meaningful way; this may be a no-operation, and implementations may
throw an
UnsupportedOperationException .
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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.
Implementations are not required to implement this method in any
meaningful way; this may be a no-operation, and implementations may
throw an
UnsupportedOperationException .
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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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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.
clone
public Object clone()
throws CloneNotSupportedException
Returns a clone copy of this instance.
- clone in interface IRandom
- a clone copy of this instance.
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.
isInitialised
public boolean isInitialised()
name
public String name()
Returns the canonical name of this instance.
- name in interface IRandom
- the canonical name of this instance.
nextByte
public byte nextByte()
throws IllegalStateException,
LimitReachedException
Returns the next 8 bits of random data generated from this instance.
- nextByte in interface IRandom
- the next 8 bits of random data generated from this instance.
LimitReachedException
- if this instance has reached its
theoretical limit for generating non-repetitive pseudo-random data.
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
.
LimitReachedException
- if this instance has reached its
theoretical limit for generating non-repetitive pseudo-random data.
setup
public abstract void setup(Map attributes)
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Free Software Foundation,
Inc. All Rights Reserved.