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      1 /*
      2  * Copyright (C) 2010 Google Inc.
      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 benchmarks;
     18 
     19 import com.google.caliper.Param;
     20 import com.google.caliper.Runner;
     21 import com.google.caliper.SimpleBenchmark;
     22 
     23 /**
     24  * How do various ways of iterating through an array compare?
     25  */
     26 public class ArrayIterationBenchmark extends SimpleBenchmark {
     27     Foo[] mArray = new Foo[27];
     28     {
     29         for (int i = 0; i < mArray.length; ++i) mArray[i] = new Foo();
     30     }
     31     public void timeArrayIteration(int reps) {
     32         for (int rep = 0; rep < reps; ++rep) {
     33             int sum = 0;
     34             for (int i = 0; i < mArray.length; i++) {
     35                 sum += mArray[i].mSplat;
     36             }
     37         }
     38     }
     39     public void timeArrayIterationCached(int reps) {
     40         for (int rep = 0; rep < reps; ++rep) {
     41             int sum = 0;
     42             Foo[] localArray = mArray;
     43             int len = localArray.length;
     44 
     45             for (int i = 0; i < len; i++) {
     46                 sum += localArray[i].mSplat;
     47             }
     48         }
     49     }
     50     public void timeArrayIterationForEach(int reps) {
     51         for (int rep = 0; rep < reps; ++rep) {
     52             int sum = 0;
     53             for (Foo a: mArray) {
     54                 sum += a.mSplat;
     55             }
     56         }
     57     }
     58 }
     59