com.scurrilous.circe.Hash Maven / Gradle / Ivy
/*******************************************************************************
* Copyright 2014 Trevor Robinson
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
******************************************************************************/
package com.scurrilous.circe;
/**
* Abstract hash function. Each actual hash function is provided using a
* {@linkplain StatefulHash stateful} derived interface. Hash functions with an
* output length that fits within an {@code int} or a {@code long} are also
* generally provided using a {@linkplain StatelessHash stateless} derived
* interface. Given a stateless hash object, a method is provided for obtaining
* a new corresponding stateful object.
*/
public interface Hash {
/**
* Returns the canonical name of this hash algorithm.
*
* @return the name of this hash algorithm
*/
String algorithm();
/**
* Returns the length in bytes of the output of this hash function.
*
* @return the hash length in bytes
*/
int length();
/**
* Returns whether this hash function supports unsafe access to arbitrary
* memory addresses using methods such as
* {@link StatefulHash#update(long, long)},
* {@link StatelessIntHash#calculate(long, long)}, or
* {@link IncrementalIntHash#resume(int, long, long)}. Such functions are
* generally implemented in native code.
*
* @return true if unsafe access is supported, false if not
*/
boolean supportsUnsafe();
}