/*
* Copyright (C) 2012 The Guava Authors
*
* 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.google.common.hash;
import com.google.caliper.BeforeExperiment;
import com.google.caliper.Benchmark;
import com.google.caliper.Param;
import java.util.Random;
/**
* Benchmarks for comparing the various {@link HashFunction functions} that we provide.
*
* <p>Parameters for the benchmark are:
* <ul>
* <li>size: The length of the byte array to hash.
* <li>hashFunctionEnum: The {@link HashFunction} to use for hashing.
* </ul>
*
* @author Kurt Alfred Kluever
*/
public class HashFunctionBenchmark {
// Use a statically configured random instance for all of the benchmarks
private static final Random random = new Random(42);
@Param({"10", "1000", "100000", "1000000"})
private int size;
@Param HashFunctionEnum hashFunctionEnum;
private byte[] testBytes;
@BeforeExperiment void setUp() {
testBytes = new byte[size];
random.nextBytes(testBytes);
}
@Benchmark int hashFunction(int reps) {
HashFunction hashFunction = hashFunctionEnum.getHashFunction();
int result = 37;
for (int i = 0; i < reps; i++) {
result ^= hashFunction.hashBytes(testBytes).asBytes()[0];
}
return result;
}
@Benchmark int hashFunctionWithOffset(int reps) {
HashFunction hashFunction = hashFunctionEnum.getHashFunction();
int result = 37;
for (int i = 0; i < reps; i++) {
result ^= hashFunction.hashBytes(testBytes, 1, testBytes.length - 1).asBytes()[0];
}
return result;
}
}