com.scurrilous.circe.Hashes 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;
import java.util.EnumSet;
/**
* Static methods to obtain various forms of abstract hash functions. Each
* method uses {@link HashProviders#best} to find the best provider for the
* given parameters and hash interface, and then calls the corresponding method
* on that provider.
*/
public final class Hashes {
private Hashes() {
}
/**
* Creates a stateful hash function using the given parameters.
*
* @param params the hash algorithm parameters
* @return a stateful hash function
* @throws UnsupportedOperationException if no provider supports the
* parameters
*/
public static StatefulHash createStateful(HashParameters params) {
return HashProviders.best(params).createStateful(params);
}
/**
* Requests a stateless, int-width hash function with the given parameters.
* Because not all stateless hash functions are incremental, this method may
* be able to return implementations not supported by or more optimized than
* {@link #getIncrementalInt}.
*
* @param params the hash algorithm parameters
* @return a stateless int-width hash function
* @throws UnsupportedOperationException if no provider supports the
* parameters as a {@link StatelessIntHash}
*/
public static StatelessIntHash getStatelessInt(HashParameters params) {
return HashProviders.best(params, EnumSet.of(HashSupport.INT_SIZED))
.getStatelessInt(params);
}
/**
* Requests a stateless, long-width hash function with the given parameters.
* Because not all stateless hash functions are incremental, this method may
* be able to return implementations not supported by or more optimized than
* {@link #getIncrementalLong}.
*
* Note that this method may return a less efficient hash function than
* {@link #getStatelessInt} for hashes of 32 bits or less.
*
* @param params the hash algorithm parameters
* @return a stateless long-width hash function
* @throws UnsupportedOperationException if no provider supports the
* parameters as a {@link StatelessLongHash}
*/
public static StatelessLongHash getStatelessLong(HashParameters params) {
return HashProviders.best(params, EnumSet.of(HashSupport.LONG_SIZED)).getStatelessLong(
params);
}
/**
* Requests an incremental, stateless, int-width hash function with the
* given parameters. Note that although an algorithm may be available in
* incremental form, some potentially more optimized implementations may not
* support that form, and therefore cannot be provided be this method.
*
* @param params the hash algorithm parameters
* @return a stateful int-width hash function
* @throws UnsupportedOperationException if no provider supports the
* parameters as an {@link IncrementalIntHash}
*/
public static IncrementalIntHash getIncrementalInt(HashParameters params) {
return HashProviders.best(params,
EnumSet.of(HashSupport.INT_SIZED, HashSupport.STATELESS_INCREMENTAL))
.getIncrementalInt(params);
}
/**
* Requests an incremental, stateless, long-width hash function with the
* given parameters. Note that although an algorithm may be available in
* incremental form, some potentially more optimized implementations may not
* support that form, and therefore cannot be provided be this method.
*
* Also note that this method may return a less efficient hash function than
* {@link #getIncrementalInt} for hashes of 32 bits or less.
*
* @param params the hash algorithm parameters
* @return a stateful long-width hash function
* @throws UnsupportedOperationException if no provider supports the
* parameters as an {@link IncrementalLongHash}
*/
public static IncrementalLongHash getIncrementalLong(HashParameters params) {
return HashProviders.best(params,
EnumSet.of(HashSupport.LONG_SIZED, HashSupport.STATELESS_INCREMENTAL))
.getIncrementalLong(params);
}
}