/*
    * 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.math;
  
  import static com.google.common.math.MathBenchmarking.ARRAY_MASK;
  import static com.google.common.math.MathBenchmarking.ARRAY_SIZE;
  import static com.google.common.math.MathBenchmarking.randomDouble;
  import static com.google.common.math.MathBenchmarking.randomPositiveDouble;
  
  import com.google.caliper.BeforeExperiment;
  import com.google.caliper.Benchmark;
  import com.google.caliper.Param;
  import com.google.common.math.DoubleMath;
  
  import java.math.RoundingMode;
  
  /**
   * Benchmarks for the rounding methods of {@code DoubleMath}.
   *
   * @author Louis Wasserman
   */
  public class DoubleMathRoundingBenchmark {
    private static final double[] doubleInIntRange = new double[ARRAY_SIZE];
    private static final double[] doubleInLongRange = new double[ARRAY_SIZE];
    private static final double[] positiveDoubles = new double[ARRAY_SIZE];
  
    @Param({"DOWN", "UP", "FLOOR", "CEILING", "HALF_EVEN", "HALF_UP", "HALF_DOWN"})
    RoundingMode mode;
  
    @BeforeExperiment
    void setUp() {
      for (int i = 0; i < ARRAY_SIZE; i++) {
        doubleInIntRange[i] = randomDouble(Integer.SIZE - 2);
        doubleInLongRange[i] = randomDouble(Long.SIZE - 2);
        positiveDoubles[i] = randomPositiveDouble();
      }
    }
  
    @Benchmark int roundToInt(int reps) {
      int tmp = 0;
      for (int i = 0; i < reps; i++) {
        int j = i & ARRAY_MASK;
        tmp += DoubleMath.roundToInt(doubleInIntRange[j], mode);
      }
      return tmp;
    }
  
    @Benchmark long roundToLong(int reps) {
      long tmp = 0;
      for (int i = 0; i < reps; i++) {
        int j = i & ARRAY_MASK;
        tmp += DoubleMath.roundToLong(doubleInLongRange[j], mode);
      }
      return tmp;
    }
  
    @Benchmark int roundToBigInteger(int reps) {
      int tmp = 0;
      for (int i = 0; i < reps; i++) {
        int j = i & ARRAY_MASK;
        tmp += DoubleMath.roundToBigInteger(positiveDoubles[j], mode).intValue();
      }
      return tmp;
    }
  
    @Benchmark int log2Round(int reps) {
      int tmp = 0;
      for (int i = 0; i < reps; i++) {
        int j = i & ARRAY_MASK;
        tmp += DoubleMath.log2(positiveDoubles[j], mode);
      }
      return tmp;
    }
  }