Package com.scurrilous.circe.impl

Class AbstractIncrementalLongHash

java.lang.Object

com.scurrilous.circe.impl.AbstractIncrementalLongHash

All Implemented Interfaces:

Hash, IncrementalLongHash, StatelessHash, StatelessLongHash

Direct Known Subclasses:

AbstractLongCrc

public abstract class AbstractIncrementalLongHash
extends java.lang.Object
implements IncrementalLongHash

Base implementation for incremental stateless long integer hash functions.

Constructor Summary

Constructors

Constructor	Description
AbstractIncrementalLongHash()

Method Summary

Modifier and Type	Method	Description
long	calculate(byte[] input)	Evaluates this hash function for the entire given input array.
long	calculate(byte[] input, int index, int length)	Evaluates this hash function for the given range of the given input array.
long	calculate(long address, long length)	Evaluates this hash function for the memory with the given address and length.
long	calculate(java.nio.ByteBuffer input)	Evaluates this hash function with the remaining contents of the given input buffer.
StatefulLongHash	createStateful()	Returns a new instance of stateful version of this hash function.
protected abstract long	initial()	The initial state of the hash function, which is the same as the output value for an empty input sequence.
long	resume(long current, byte[] input)	Evaluates this hash function as if the entire given input array were appended to the previously hashed input.
long	resume(long current, byte[] input, int index, int length)	Evaluates this hash function as if the given range of the given input array were appended to the previously hashed input.
long	resume(long current, long address, long length)	Evaluates this hash function as if the memory with the given address and length were appended to the previously hashed input.
long	resume(long current, java.nio.ByteBuffer input)	Evaluates this hash function as if the remaining contents of the given input buffer were appended to the previously hashed input.
protected abstract long	resumeUnchecked(long current, byte[] input, int index, int length)	Evaluates this hash function as if the given range of the given input array were appended to the previously hashed input.
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).

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

Constructor Detail

AbstractIncrementalLongHash

public AbstractIncrementalLongHash()

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

createStateful

public StatefulLongHash createStateful()

Description copied from interface: StatelessLongHash

Returns a new instance of stateful version of this hash function.

Specified by:

createStateful in interface StatelessHash

Specified by:

createStateful in interface StatelessLongHash

Returns:

the stateful version of this hash function

calculate

public long calculate(byte[] input)

Description copied from interface: StatelessLongHash

Evaluates this hash function for the entire given input array.

Specified by:

calculate in interface StatelessLongHash

Parameters:

input - the input array

Returns:

the output of the hash function

calculate

public long calculate(byte[] input,
                      int index,
                      int length)

Description copied from interface: StatelessLongHash

Evaluates this hash function for the given range of the given input array.

Specified by:

calculate in interface StatelessLongHash

Parameters:

input - the input array

index - the starting index of the first input byte

length - the length of the input range

Returns:

the output of the hash function

calculate

public long calculate(java.nio.ByteBuffer input)

Description copied from interface: StatelessLongHash

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

Specified by:

calculate in interface StatelessLongHash

Parameters:

input - the input buffer

Returns:

the output of the hash function

calculate

public long calculate(long address,
                      long length)

Description copied from interface: StatelessLongHash

Evaluates this hash function for the 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:

calculate in interface StatelessLongHash

Parameters:

address - the base address of the input

length - the length of the input

Returns:

the output of the hash function

See Also:

Hash.supportsUnsafe()

resume

public long resume(long current,
                   byte[] input)

Description copied from interface: IncrementalLongHash

Evaluates this hash function as if the entire given input array were appended to the previously hashed input.

Specified by:

resume in interface IncrementalLongHash

Parameters:

current - the hash output for input hashed so far

input - the input array

Returns:

the output of the hash function for the concatenated input

resume

public long resume(long current,
                   byte[] input,
                   int index,
                   int length)

Description copied from interface: IncrementalLongHash

Evaluates this hash function as if the given range of the given input array were appended to the previously hashed input.

Specified by:

resume in interface IncrementalLongHash

Parameters:

current - the hash output for input hashed so far

input - the input array

index - the starting index of the first input byte

length - the length of the input range

Returns:

the output of the hash function for the concatenated input

resume

public long resume(long current,
                   java.nio.ByteBuffer input)

Description copied from interface: IncrementalLongHash

Evaluates this hash function as if the remaining contents of the given input buffer were appended to the previously hashed input. This method leaves the buffer position at the limit.

Specified by:

resume in interface IncrementalLongHash

Parameters:

current - the hash output for input hashed so far

input - the input buffer

Returns:

the output of the hash function for the concatenated input

resume

public long resume(long current,
                   long address,
                   long length)

Description copied from interface: IncrementalLongHash

Evaluates this hash function as if the memory with the given address and length were appended to the previously hashed input. The arguments are generally not checked in any way and will likely lead to a VM crash or undefined results if invalid.

Specified by:

resume in interface IncrementalLongHash

Parameters:

current - the hash output for input hashed so far

address - the base address of the input

length - the length of the input

Returns:

the output of the hash function for the concatenated input

See Also:

Hash.supportsUnsafe()

initial

protected abstract long initial()

The initial state of the hash function, which is the same as the output value for an empty input sequence.

Returns:

the initial hash state/output

resumeUnchecked

protected abstract long resumeUnchecked(long current,
                                        byte[] input,
                                        int index,
                                        int length)

Evaluates this hash function as if the given range of the given input array were appended to the previously hashed input. The index and length parameters have already been validated.

Parameters:

current - the hash output for input hashed so far

input - the input array

index - the starting index of the first input byte

length - the length of the input range

Returns:

the output of the hash function for the concatenated input