Package com.scurrilous.circe.impl

Class AbstractStatefulHash

java.lang.Object

com.scurrilous.circe.impl.AbstractStatefulHash

All Implemented Interfaces:

Hash, StatefulHash

Direct Known Subclasses:

IncrementalIntStatefulHash, IncrementalLongStatefulHash, JavaCrc32

public abstract class AbstractStatefulHash
extends java.lang.Object
implements StatefulHash

Base implementation for stateful hash functions.

Constructor Summary

Constructors

Constructor	Description
AbstractStatefulHash()

Method Summary

Modifier and Type	Method	Description
byte	getByte()	Returns the first byte of the output of this hash function.
byte[]	getBytes()	Returns a new byte array containing the output of this hash function.
int	getBytes(byte[] output, int index, int maxLength)	Writes the output of this hash function into the given byte array at the given offset.
short	getShort()	Returns the first two bytes of the output of this hash function as a little-endian short.
boolean	supportsUnsafe()	Returns whether this hash function supports unsafe access to arbitrary memory addresses using methods such as StatefulHash.update(long, long), StatelessIntHash.calculate(long, long), or IncrementalIntHash.resume(int, long, long).
void	update(byte[] input)	Updates the state of this hash function with the entire given input array.
void	update(byte[] input, int index, int length)	Updates the state of this hash function with the given range of the given input array.
void	update(long address, long length)	Updates the state of this hash function with memory with the given address and length.
void	update(java.nio.ByteBuffer input)	Updates the state of this hash function with the remaining contents of the given input buffer.
protected abstract void	updateUnchecked(byte[] input, int index, int length)	Updates the state of this hash function with the given range of the given input array.
protected void	writeBytes(byte[] output, int index, int length)	Writes the output of this hash function into the given range of the given byte array.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface com.scurrilous.circe.Hash

algorithm, length

Methods inherited from interface com.scurrilous.circe.StatefulHash

createNew, getInt, getLong, reset, supportsIncremental

Constructor Detail

AbstractStatefulHash

public AbstractStatefulHash()

Method Detail

supportsUnsafe

public boolean supportsUnsafe()

Description copied from interface: Hash

Returns whether this hash function supports unsafe access to arbitrary memory addresses using methods such as StatefulHash.update(long, long), StatelessIntHash.calculate(long, long), or IncrementalIntHash.resume(int, long, long). Such functions are generally implemented in native code.

Specified by:

supportsUnsafe in interface Hash

Returns:

true if unsafe access is supported, false if not

update

public void update(byte[] input)

Description copied from interface: StatefulHash

Updates the state of this hash function with the entire given input array.

Specified by:

update in interface StatefulHash

Parameters:

input - the input array

update

public void update(byte[] input,
                   int index,
                   int length)

Description copied from interface: StatefulHash

Updates the state of this hash function with the given range of the given input array.

Specified by:

update in interface StatefulHash

Parameters:

input - the input array

index - the starting index of the first input byte

length - the length of the input range

update

public void update(java.nio.ByteBuffer input)

Description copied from interface: StatefulHash

Updates the state of this hash function with the remaining contents of the given input buffer. This method leaves the buffer position at the limit.

Specified by:

update in interface StatefulHash

Parameters:

input - the input buffer

update

public void update(long address,
                   long length)

Description copied from interface: StatefulHash

Updates the state of this hash function with memory with the given address and length. The arguments are generally not checked in any way and will likely lead to a VM crash or undefined results if invalid.

Specified by:

update in interface StatefulHash

Parameters:

address - the base address of the input

length - the length of the input

See Also:

Hash.supportsUnsafe()

updateUnchecked

protected abstract void updateUnchecked(byte[] input,
                                        int index,
                                        int length)

Updates the state of this hash function with the given range of the given input array. The index and length parameters have already been validated.

Parameters:

input - the input array

index - the starting index of the first input byte

length - the length of the input range

getBytes

public byte[] getBytes()

Description copied from interface: StatefulHash

Returns a new byte array containing the output of this hash function. The caller may freely modify the contents of the array.

Specified by:

getBytes in interface StatefulHash

Returns:

a new byte array containing the hash output

getBytes

public int getBytes(byte[] output,
                    int index,
                    int maxLength)

Description copied from interface: StatefulHash

Writes the output of this hash function into the given byte array at the given offset.

Specified by:

getBytes in interface StatefulHash

Parameters:

output - the destination array for the output

index - the starting index of the first output byte

maxLength - the maximum number of bytes to write

Returns:

the number of bytes written

writeBytes

protected void writeBytes(byte[] output,
                          int index,
                          int length)

Writes the output of this hash function into the given range of the given byte array. The inputs have already been validated.

Parameters:

output - the destination array for the output

index - the starting index of the first output byte

length - the number of bytes to write

getByte

public byte getByte()

Description copied from interface: StatefulHash

Returns the first byte of the output of this hash function.

Specified by:

getByte in interface StatefulHash

Returns:

the first output byte

getShort

public short getShort()

Description copied from interface: StatefulHash

Returns the first two bytes of the output of this hash function as a little-endian short. If the output is less than two bytes, the remaining bytes are set to 0.

Specified by:

getShort in interface StatefulHash

Returns:

the first two output bytes as a short