/*
 * Copyright (C) 2011 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.common.collect.HashMultiset;
import com.google.common.collect.Multiset;

import java.util.ArrayList;
import java.util.List;
import java.util.Random;

/**
 * Benchmark for HashMultiset.add for an already-present element.
 *
 * @author Louis Wasserman
 */
public class HashMultisetAddPresentBenchmark {
  private static final int ARRAY_MASK = 0x0ffff;
  private static final int ARRAY_SIZE = 0x10000;
  List<Multiset<Integer>> multisets = new ArrayList<Multiset<Integer>>(0x10000);
  int[] queries = new int[ARRAY_SIZE];

  @BeforeExperiment
  void setUp() {
    Random random = new Random();
    multisets.clear();
    for (int i = 0; i < ARRAY_SIZE; i++) {
      HashMultiset<Integer> multiset = HashMultiset.<Integer>create();
      multisets.add(multiset);
      queries[i] = random.nextInt();
      multiset.add(queries[i]);
    }
  }

  @Benchmark int add(int reps) {
    int tmp = 0;
    for (int i = 0; i < reps; i++) {
      int j = i & ARRAY_MASK;
      tmp += multisets.get(j).add(queries[j], 4);
    }
    return tmp;
  }
}