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)Modifier and Type | Field and Description |
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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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Modifier | Constructor and Description |
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protected |
BasePRNGStandalone(String name)
Trivial constructor for use by concrete subclasses.
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Modifier and Type | Method and Description |
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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.
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Object |
clone()
Returns a clone copy of this instance.
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abstract void |
fillBlock() |
void |
init(Map<String,byte[]> attributes)
Initialises the pseudo-random number generator scheme with the
appropriate attributes.
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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) |
protected final String name
protected volatile boolean initialised
protected volatile byte[] buffer
protected int ndx
protected BasePRNGStandalone(String name)
Trivial constructor for use by concrete subclasses.
name
- the canonical name of this instance.public String name()
IRandomStandalone
Returns the canonical name of this instance.
name
in interface IRandomStandalone
public void init(Map<String,byte[]> attributes)
IRandomStandalone
Initialises the pseudo-random number generator scheme with the appropriate attributes.
init
in interface IRandomStandalone
attributes
- a set of name-value pairs that describe the desired
future instance behaviour.public byte nextByte() throws IllegalStateException
IRandomStandalone
Returns the next 8 bits of random data generated from this instance.
nextByte
in interface IRandomStandalone
IllegalStateException
- if the instance is not yet initialised.public void nextBytes(byte[] out) throws IllegalStateException
IllegalStateException
public void nextBytes(byte[] out, int offset, int length) throws IllegalStateException
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.
nextBytes
in interface IRandomStandalone
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
.IllegalStateException
- if the instance is not yet initialised.public void addRandomByte(byte b)
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
.
addRandomByte
in interface IRandomStandalone
b
- The byte to add.public void addRandomBytes(byte[] buffer)
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
.
addRandomBytes
in interface IRandomStandalone
buffer
- The buffer of new random bytes to add.public void addRandomBytes(byte[] buffer, int offset, int length)
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
.
addRandomBytes
in interface IRandomStandalone
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.public boolean isInitialised()
public Object clone() throws CloneNotSupportedException
IRandomStandalone
Returns a clone copy of this instance.
clone
in interface IRandomStandalone
clone
in class Object
CloneNotSupportedException
public abstract void fillBlock()