| /* |
| * 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 hasher(int reps) { |
| HashFunction hashFunction = hashFunctionEnum.getHashFunction(); |
| int result = 37; |
| for (int i = 0; i < reps; i++) { |
| result ^= hashFunction.newHasher().putBytes(testBytes).hash().asBytes()[0]; |
| } |
| return result; |
| } |
| |
| @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; |
| } |
| } |