112 lines
3.2 KiB
Java
112 lines
3.2 KiB
Java
/*
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* Copyright (C) 2017 The Guava Authors
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*
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* Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
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* in compliance with the License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software distributed under the License
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* is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
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* or implied. See the License for the specific language governing permissions and limitations under
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* the License.
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*/
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package com.google.common.io;
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import com.google.caliper.BeforeExperiment;
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import com.google.caliper.Benchmark;
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import com.google.caliper.Param;
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import com.google.caliper.api.VmOptions;
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import java.io.IOException;
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import java.io.StringReader;
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import java.io.StringWriter;
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import java.nio.CharBuffer;
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import java.util.Random;
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/**
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* Benchmarks for {@link CharStreams#copy}.
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*
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* <p>{@link CharStreams#copy} has type specific optimizations for various common Appendable and
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* Reader implementations, this compares the performance of the different options.
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*/
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// These benchmarks allocate a lot of data so use a large heap
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@VmOptions({"-Xms12g", "-Xmx12g", "-d64"})
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public class CharStreamsCopyBenchmark {
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enum CopyStrategy {
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OLD {
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@Override
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long copy(Readable from, Appendable to) throws IOException {
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CharBuffer buf = CharStreams.createBuffer();
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long total = 0;
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while (from.read(buf) != -1) {
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buf.flip();
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to.append(buf);
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total += buf.remaining();
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buf.clear();
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}
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return total;
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}
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},
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NEW {
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@Override
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long copy(Readable from, Appendable to) throws IOException {
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return CharStreams.copy(from, to);
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}
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};
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abstract long copy(Readable from, Appendable to) throws IOException;
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}
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enum TargetSupplier {
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STRING_WRITER {
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@Override
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Appendable get(int sz) {
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return new StringWriter(sz);
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}
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},
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STRING_BUILDER {
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@Override
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Appendable get(int sz) {
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return new StringBuilder(sz);
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}
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};
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abstract Appendable get(int sz);
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}
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@Param CopyStrategy strategy;
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@Param TargetSupplier target;
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@Param({"10", "1024", "1048576"})
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int size;
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String data;
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@BeforeExperiment
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public void setUp() {
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// precalculate some random strings of ascii characters.
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StringBuilder sb = new StringBuilder();
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Random random = new Random(0xdeadbeef); // for unpredictable but reproducible behavior
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sb.ensureCapacity(size);
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for (int k = 0; k < size; k++) {
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// [9-127) includes all ascii non-control characters
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sb.append((char) (random.nextInt(127 - 9) + 9));
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}
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data = sb.toString();
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}
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@Benchmark
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public long timeCopy(int reps) throws IOException {
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long r = 0;
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final String localData = data;
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final TargetSupplier localTarget = target;
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final CopyStrategy localStrategy = strategy;
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for (int i = 0; i < reps; i++) {
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Appendable appendable = localTarget.get(localData.length());
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r += localStrategy.copy(new StringReader(localData), appendable);
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}
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return r;
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}
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}
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