1 /*
2  * Copyright (C) 2017 The Guava Authors
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
5  * in compliance with the License. You may obtain a copy of the License at
6  *
7  * http://www.apache.org/licenses/LICENSE-2.0
8  *
9  * Unless required by applicable law or agreed to in writing, software distributed under the License
10  * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
11  * or implied. See the License for the specific language governing permissions and limitations under
12  * the License.
13  */
14 
15 package com.google.common.io;
16 
17 import com.google.caliper.BeforeExperiment;
18 import com.google.caliper.Benchmark;
19 import com.google.caliper.Param;
20 import com.google.caliper.api.VmOptions;
21 import java.io.IOException;
22 import java.io.StringReader;
23 import java.io.StringWriter;
24 import java.nio.CharBuffer;
25 import java.util.Random;
26 
27 /**
28  * Benchmarks for {@link CharStreams#copy}.
29  *
30  * <p>{@link CharStreams#copy} has type specific optimizations for various common Appendable and
31  * Reader implementations, this compares the performance of the different options.
32  */
33 // These benchmarks allocate a lot of data so use a large heap
34 @VmOptions({"-Xms12g", "-Xmx12g", "-d64"})
35 public class CharStreamsCopyBenchmark {
36   enum CopyStrategy {
37     OLD {
38       @Override
copy(Readable from, Appendable to)39       long copy(Readable from, Appendable to) throws IOException {
40         CharBuffer buf = CharStreams.createBuffer();
41         long total = 0;
42         while (from.read(buf) != -1) {
43           buf.flip();
44           to.append(buf);
45           total += buf.remaining();
46           buf.clear();
47         }
48         return total;
49       }
50     },
51     NEW {
52       @Override
copy(Readable from, Appendable to)53       long copy(Readable from, Appendable to) throws IOException {
54         return CharStreams.copy(from, to);
55       }
56     };
57 
copy(Readable from, Appendable to)58     abstract long copy(Readable from, Appendable to) throws IOException;
59   }
60 
61   enum TargetSupplier {
62     STRING_WRITER {
63       @Override
get(int sz)64       Appendable get(int sz) {
65         return new StringWriter(sz);
66       }
67     },
68     STRING_BUILDER {
69       @Override
get(int sz)70       Appendable get(int sz) {
71         return new StringBuilder(sz);
72       }
73     };
74 
get(int sz)75     abstract Appendable get(int sz);
76   }
77 
78   @Param CopyStrategy strategy;
79   @Param TargetSupplier target;
80 
81   @Param({"10", "1024", "1048576"})
82   int size;
83 
84   String data;
85 
86   @BeforeExperiment
setUp()87   public void setUp() {
88     // precalculate some random strings of ascii characters.
89     StringBuilder sb = new StringBuilder();
90     Random random = new Random(0xdeadbeef); // for unpredictable but reproducible behavior
91     sb.ensureCapacity(size);
92     for (int k = 0; k < size; k++) {
93       // [9-127) includes all ascii non-control characters
94       sb.append((char) (random.nextInt(127 - 9) + 9));
95     }
96     data = sb.toString();
97   }
98 
99   @Benchmark
timeCopy(int reps)100   public long timeCopy(int reps) throws IOException {
101     long r = 0;
102     final String localData = data;
103     final TargetSupplier localTarget = target;
104     final CopyStrategy localStrategy = strategy;
105     for (int i = 0; i < reps; i++) {
106       Appendable appendable = localTarget.get(localData.length());
107       r += localStrategy.copy(new StringReader(localData), appendable);
108     }
109     return r;
110   }
111 }
112