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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 com.google.caliper.runner.CaliperMain;
     23 import com.google.common.base.CharMatcher.FastMatcher;
     24 
     25 import java.util.BitSet;
     26 import java.util.Random;
     27 
     28 /**
     29  * Benchmark for the {@link CharMatcher#WHITESPACE} implementation.
     30  */
     31 public 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