1/*
2 * Copyright (C) 2010 The Guava Authors
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package com.google.common.base;
18
19import com.google.caliper.BeforeExperiment;
20import com.google.caliper.Benchmark;
21import com.google.caliper.Param;
22import com.google.caliper.runner.CaliperMain;
23import com.google.common.base.CharMatcher.FastMatcher;
24
25import java.util.BitSet;
26import java.util.Random;
27
28/**
29 * Benchmark for the {@link CharMatcher#WHITESPACE} implementation.
30 */
31public class WhitespaceMatcherBenchmark {
32  private static final int STRING_LENGTH = 10000;
33
34  private static final String OLD_WHITESPACE_TABLE =
35      "\u0001\u0000\u00a0\u0000\u0000\u0000\u0000\u0000"
36      + "\u0000\u0009\n\u000b\u000c\r\u0000\u0000\u2028\u2029\u0000\u0000\u0000\u0000\u0000\u202f"
37      + "\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0020\u0000\u0000\u0000\u0000\u0000"
38      + "\u0000\u0000\u0000\u0000\u0000\u3000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000"
39      + "\u0000\u0000\u0085\u2000\u2001\u2002\u2003\u2004\u2005\u2006\u2007\u2008\u2009\u200a"
40      + "\u0000\u0000\u0000\u0000\u0000\u205f\u1680\u0000\u0000\u180e\u0000\u0000\u0000";
41
42  public static final CharMatcher OLD_WHITESPACE = new FastMatcher("CharMatcher.WHITESPACE") {
43    @Override public boolean matches(char c) {
44      return OLD_WHITESPACE_TABLE.charAt(c % 79) == c;
45    }
46  };
47
48  @Param
49  private boolean useNew;
50
51  @Param({"20", "50", "80"})
52  private int percentMatching;
53
54  private String teststring;
55  private CharMatcher matcher;
56
57  public static void main(String[] args) throws Exception {
58    CaliperMain.main(WhitespaceMatcherBenchmark.class, new String[] {});
59  }
60
61  @BeforeExperiment
62  protected void setUp() {
63    BitSet bitSet = new BitSet();
64    for (int i = 0; i < OLD_WHITESPACE_TABLE.length(); i++) {
65      bitSet.set(OLD_WHITESPACE_TABLE.charAt(i));
66    }
67    bitSet.clear(0);
68    bitSet.clear(1);
69    matcher = useNew ? CharMatcher.WHITESPACE : OLD_WHITESPACE;
70    teststring = newTestString(new Random(1), bitSet, percentMatching);
71  }
72
73  @Benchmark public int countIn(int reps) {
74    int result = 0;
75    CharMatcher matcher = this.matcher;
76    String teststring = this.teststring;
77    for (int i = 0; i < reps; i++) {
78      result += matcher.countIn(teststring);
79    }
80    return result;
81  }
82
83  @Benchmark public int collapseFrom(int reps) {
84    int result = 0;
85    CharMatcher matcher = this.matcher;
86    String teststring = this.teststring;
87    for (int i = 0; i < reps; i++) {
88      result += System.identityHashCode(matcher.collapseFrom(teststring, ' '));
89    }
90    return result;
91  }
92
93  private static String allMatchingChars(BitSet bitSet) {
94    final char[] result = new char[bitSet.cardinality()];
95    for (int j = 0, c = bitSet.nextSetBit(0); j < result.length; ++j) {
96      result[j] = (char) c;
97      c = bitSet.nextSetBit(c + 1);
98    }
99    return new String(result);
100  }
101
102  private static String newTestString(Random random, BitSet bitSet, int percentMatching) {
103    final String allMatchingChars = allMatchingChars(bitSet);
104    final char[] result = new char[STRING_LENGTH];
105    // Fill with matching chars.
106    for (int i = 0; i < result.length; i++) {
107      result[i] = allMatchingChars.charAt(random.nextInt(allMatchingChars.length()));
108    }
109    // Replace some of chars by non-matching.
110    int remaining = (int) ((100 - percentMatching) * result.length / 100.0 + 0.5);
111    while (remaining > 0) {
112      final char c = (char) random.nextInt();
113      if (bitSet.get(c)) {
114        final int pos = random.nextInt(result.length);
115        if (bitSet.get(result[pos])) {
116          result[pos] = c;
117          remaining--;
118        }
119      }
120    }
121    return new String(result);
122  }
123}
124