Package com.scurrilous.circe.impl

Class AbstractIncrementalIntHash

java.lang.Object

com.scurrilous.circe.impl.AbstractIncrementalIntHash

All Implemented Interfaces:

Hash, IncrementalIntHash, StatelessHash, StatelessIntHash

Direct Known Subclasses:

AbstractIntCrc, Sse42Crc32C

public abstract class AbstractIncrementalIntHash
extends java.lang.Object
implements IncrementalIntHash

Base implementation for incremental stateless integer hash functions.

Constructor Summary

Constructors

Constructor	Description
AbstractIncrementalIntHash()

Method Summary

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

AbstractIncrementalIntHash

public AbstractIncrementalIntHash()

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 StatefulIntHash createStateful()

Description copied from interface: StatelessIntHash

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

Specified by:

createStateful in interface StatelessHash

Specified by:

createStateful in interface StatelessIntHash

Returns:

the stateful version of this hash function

calculate

public int calculate(byte[] input)

Description copied from interface: StatelessIntHash

Evaluates this hash function for the entire given input array.

Specified by:

calculate in interface StatelessIntHash

Parameters:

input - the input array

Returns:

the output of the hash function

calculate

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

Description copied from interface: StatelessIntHash

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

Specified by:

calculate in interface StatelessIntHash

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 int calculate(java.nio.ByteBuffer input)

Description copied from interface: StatelessIntHash

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 StatelessIntHash

Parameters:

input - the input buffer

Returns:

the output of the hash function

calculate

public int calculate(long address,
                     long length)

Description copied from interface: StatelessIntHash

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 StatelessIntHash

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 int resume(int current,
                  byte[] input)

Description copied from interface: IncrementalIntHash

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

Specified by:

resume in interface IncrementalIntHash

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

Description copied from interface: IncrementalIntHash

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 IncrementalIntHash

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 int resume(int current,
                  java.nio.ByteBuffer input)

Description copied from interface: IncrementalIntHash

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 IncrementalIntHash

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

Description copied from interface: IncrementalIntHash

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 IncrementalIntHash

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 int 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 int resumeUnchecked(int 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