/*
 * Copyright (c) BELLSOFT. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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 * questions.
 */

package org.openjdk.bench.java.lang;

import org.openjdk.jmh.annotations.Benchmark;
import org.openjdk.jmh.annotations.BenchmarkMode;
import org.openjdk.jmh.annotations.Mode;
import org.openjdk.jmh.annotations.OperationsPerInvocation;
import org.openjdk.jmh.annotations.Scope;
import org.openjdk.jmh.annotations.Setup;
import org.openjdk.jmh.annotations.State;
import org.openjdk.jmh.infra.Blackhole;
import org.openjdk.jmh.annotations.OutputTimeUnit;
import org.openjdk.jmh.annotations.Level;

import java.lang.Double;
import java.lang.Math;
import java.util.Arrays;
import java.util.Random;
import java.util.concurrent.TimeUnit;

@BenchmarkMode(Mode.AverageTime)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
@State(Scope.Thread)
public class DoubleSignum {

    double[] mostlyZero, mostlyNan, mostlyPos, mostlyNeg, random;
    final int TESTSIZE = 1000;
    
    // cover all branches
    static void prefixMixed(double[] data) {
        data[0] = 0.0d;
        data[1] = Double.NaN;
        data[2] = 2.39d;
        data[3] = -2.39d;
    }
    
    @Setup(Level.Iteration)
    public void generateData() {                
        mostlyZero = new double[TESTSIZE];
        prefixMixed(mostlyZero);
        
        mostlyNan = new double[TESTSIZE];
        Arrays.fill(mostlyNan, Double.NaN);
        prefixMixed(mostlyNan);
        
        mostlyPos = new double[TESTSIZE];
        Arrays.fill(mostlyPos, 2.39f);
        prefixMixed(mostlyPos);
        
        mostlyNeg = new double[TESTSIZE];
        Arrays.fill(mostlyNeg, -2.39f);
        prefixMixed(mostlyNeg);
        
        Random r = new Random();        
        random = new double[TESTSIZE];
        for(int i = 0; i < TESTSIZE; i++)
            random[i] = r.nextDouble() - 0.5d;
        prefixMixed(random);
    }

    @Benchmark
    @OperationsPerInvocation(TESTSIZE)
    public void ofMostlyNaN(Blackhole bh) {
        for(double d : mostlyNan)
            bh.consume(Math.signum(d));
    }

    @Benchmark
    @OperationsPerInvocation(TESTSIZE)
    public void ofMostlyZero(Blackhole bh) {
        for(double d : mostlyZero)
            bh.consume(Math.signum(d));
    }

    @Benchmark
    @OperationsPerInvocation(TESTSIZE)
    public void ofMostlyPos(Blackhole bh) {
        for(double d : mostlyPos)
            bh.consume(Math.signum(d));
    }

    @Benchmark
    @OperationsPerInvocation(TESTSIZE)
    public void ofMostlyNeg(Blackhole bh) {
        for(double d : mostlyNeg)
            bh.consume(Math.signum(d));
    }
    
    @Benchmark
    @OperationsPerInvocation(TESTSIZE)
    public void ofRandom(Blackhole bh) {
        for(double d : random)
            bh.consume(Math.signum(d));
    }
    
    @Benchmark
    @OperationsPerInvocation(TESTSIZE)
    public void overhead(Blackhole bh) {
        for (double d : random)
            bh.consume(d);
    }
}