/*
    * Copyright (C) 2010 The Guava Authors
    *
    * Licensed under the Apache License, Version 2.0 (the "License");
    * you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    *
    * http://www.apache.org/licenses/LICENSE-2.0
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package com.google.common.collect;
  
  import com.google.caliper.BeforeExperiment;
  import com.google.caliper.Benchmark;
  import com.google.caliper.Param;
  import com.google.common.collect.BenchmarkHelpers.SetImpl;
  import com.google.common.collect.CollectionBenchmarkSampleData.Element;
  
  import java.util.Set;
  
  /**
   * A microbenchmark that tests the performance of contains() on various Set
   * implementations.
   *
   * @author Kevin Bourrillion
   */
  public class SetContainsBenchmark {
    // Start at 4.88 then multiply by 2*2^phi <evil cackle> - The goal is be uniform
    // yet visit a variety of "values-relative-to-the-next-power-of-2"
    @Param({"5", "30", "180", "1100", "6900", "43000", "260000"}) // "1600000", "9800000"
    private int size;
  
    // TODO(kevinb): look at exact (==) hits vs. equals() hits?
    @Param({"0.2", "0.8"})
    private double hitRate;
  
    @Param("true")
    private boolean isUserTypeFast;
  
    // "" means no fixed seed
    @Param("")
    private SpecialRandom random;
  
    @Param({"Hash", "Immutable"})
    private SetImpl impl;
  
    // the following must be set during setUp
    private Element[] queries;
    private Set<Element> setToTest;
  
    @BeforeExperiment void setUp() {
      CollectionBenchmarkSampleData sampleData = 
          new CollectionBenchmarkSampleData(
              isUserTypeFast, random, hitRate, size);
      
      this.setToTest = impl.create(sampleData.getValuesInSet());
      this.queries = sampleData.getQueries();
    }
  
    @Benchmark boolean contains(int reps) {
      // Paranoia: acting on hearsay that accessing fields might be slow
      // Should write a benchmark to test that!
      Set<Element> set = setToTest;
      Element[] queries = this.queries;
  
      int mask = queries.length - 1;
  
      boolean dummy = false;
      for (int i = 0; i < reps; i++) {
        dummy ^= set.contains(queries[i & mask]);
      }
      return dummy;
    }
  }