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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 
17 package com.google.common.base;
18 
19 import com.google.caliper.BeforeExperiment;
20 import com.google.caliper.Benchmark;
21 import com.google.caliper.Param;
22 import java.util.BitSet;
23 import java.util.Random;
24 
25 /** Benchmark for the {@link CharMatcher#whitespace} implementation. */
26 public class WhitespaceMatcherBenchmark {
27   private static final int STRING_LENGTH = 10000;
28 
29   private static final String OLD_WHITESPACE_TABLE =
30       "\u0001\u0000\u00a0\u0000\u0000\u0000\u0000\u0000"
31           + "\u0000\u0009\n\u000b\u000c\r\u0000\u0000\u2028\u2029\u0000\u0000\u0000\u0000\u0000"
32           + "\u202f\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0020\u0000\u0000\u0000\u0000"
33           + "\u0000\u0000\u0000\u0000\u0000\u0000\u3000\u0000\u0000\u0000\u0000\u0000\u0000\u0000"
34           + "\u0000\u0000\u0000\u0085\u2000\u2001\u2002\u2003\u2004\u2005\u2006\u2007\u2008\u2009"
35           + "\u200a\u0000\u0000\u0000\u0000\u0000\u205f\u1680\u0000\u0000\u180e\u0000\u0000\u0000";
36 
37   public static final CharMatcher OLD_WHITESPACE =
38       new CharMatcher() {
39         @Override
40         public boolean matches(char c) {
41           return OLD_WHITESPACE_TABLE.charAt(c % 79) == c;
42         }
43       };
44 
45   @Param private boolean useNew;
46 
47   @Param({"20", "50", "80"})
48   private int percentMatching;
49 
50   private String teststring;
51   private CharMatcher matcher;
52 
53   @BeforeExperiment
setUp()54   protected void setUp() {
55     BitSet bitSet = new BitSet();
56     for (int i = 0; i < OLD_WHITESPACE_TABLE.length(); i++) {
57       bitSet.set(OLD_WHITESPACE_TABLE.charAt(i));
58     }
59     bitSet.clear(0);
60     bitSet.clear(1);
61     matcher = useNew ? CharMatcher.whitespace() : OLD_WHITESPACE;
62     teststring = newTestString(new Random(1), bitSet, percentMatching);
63   }
64 
65   @Benchmark
countIn(int reps)66   public int countIn(int reps) {
67     int result = 0;
68     CharMatcher matcher = this.matcher;
69     String teststring = this.teststring;
70     for (int i = 0; i < reps; i++) {
71       result += matcher.countIn(teststring);
72     }
73     return result;
74   }
75 
76   @Benchmark
collapseFrom(int reps)77   public int collapseFrom(int reps) {
78     int result = 0;
79     CharMatcher matcher = this.matcher;
80     String teststring = this.teststring;
81     for (int i = 0; i < reps; i++) {
82       result += System.identityHashCode(matcher.collapseFrom(teststring, ' '));
83     }
84     return result;
85   }
86 
allMatchingChars(BitSet bitSet)87   private static String allMatchingChars(BitSet bitSet) {
88     final char[] result = new char[bitSet.cardinality()];
89     for (int j = 0, c = bitSet.nextSetBit(0); j < result.length; ++j) {
90       result[j] = (char) c;
91       c = bitSet.nextSetBit(c + 1);
92     }
93     return new String(result);
94   }
95 
newTestString(Random random, BitSet bitSet, int percentMatching)96   private static String newTestString(Random random, BitSet bitSet, int percentMatching) {
97     final String allMatchingChars = allMatchingChars(bitSet);
98     final char[] result = new char[STRING_LENGTH];
99     // Fill with matching chars.
100     for (int i = 0; i < result.length; i++) {
101       result[i] = allMatchingChars.charAt(random.nextInt(allMatchingChars.length()));
102     }
103     // Replace some of chars by non-matching.
104     int remaining = (int) ((100 - percentMatching) * result.length / 100.0 + 0.5);
105     while (remaining > 0) {
106       final char c = (char) random.nextInt();
107       if (bitSet.get(c)) {
108         final int pos = random.nextInt(result.length);
109         if (bitSet.get(result[pos])) {
110           result[pos] = c;
111           remaining--;
112         }
113       }
114     }
115     return new String(result);
116   }
117 }
118