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package org.openjdk.bench.java.lang.foreign;

import org.openjdk.jmh.annotations.Benchmark;
import org.openjdk.jmh.annotations.BenchmarkMode;
import org.openjdk.jmh.annotations.Fork;
import org.openjdk.jmh.annotations.Measurement;
import org.openjdk.jmh.annotations.Mode;
import org.openjdk.jmh.annotations.OutputTimeUnit;
import org.openjdk.jmh.annotations.Param;
import org.openjdk.jmh.annotations.Scope;
import org.openjdk.jmh.annotations.Setup;
import org.openjdk.jmh.annotations.State;
import org.openjdk.jmh.annotations.Warmup;

import java.lang.foreign.Arena;
import java.lang.foreign.MemorySegment;
import java.lang.foreign.ValueLayout;
import java.nio.ByteBuffer;
import java.util.Arrays;
import java.util.concurrent.TimeUnit;

@BenchmarkMode(Mode.AverageTime)
@Warmup(iterations = 5, time = 500, timeUnit = TimeUnit.MILLISECONDS)
@Measurement(iterations = 10, time = 500, timeUnit = TimeUnit.MILLISECONDS)
@State(Scope.Thread)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
@Fork(value = 3)
public class SegmentBulkFill {

    @Param({"2", "3", "4", "5", "6", "7", "8", "64", "512",
            "4096", "32768", "262144", "2097152", "16777216", "134217728"})
    public int ELEM_SIZE;

    byte[] array;
    MemorySegment heapSegment;
    MemorySegment nativeSegment;
    MemorySegment unalignedSegment;
    ByteBuffer buffer;

    @Setup
    public void setup() {
        array = new byte[ELEM_SIZE];
        heapSegment = MemorySegment.ofArray(array);
        nativeSegment = Arena.ofAuto().allocate(ELEM_SIZE, 8);
        unalignedSegment = Arena.ofAuto().allocate(ELEM_SIZE + 1, 8).asSlice(1);
        buffer = ByteBuffer.wrap(array);
    }

    @Benchmark
    public void arraysFill() {
        Arrays.fill(array, (byte) 0);
    }

    @Benchmark
    public void arraysFillLoop() {
        for (int i = 0; i < array.length; i++) {
            array[i] = 0;
        }
    }

    @Benchmark
    public void bufferFillLoop() {
        for (int i = 0; i < array.length; i++) {
            buffer.put(i, (byte)0);
        }
    }

    @Fork(value = 3, jvmArgs = {"-Djava.lang.foreign.native.threshold.power.fill=31"})
    @Benchmark
    public void heapSegmentFillJava() {
        heapSegment.fill((byte) 0);
    }

    @Fork(value = 3, jvmArgs = {"-Djava.lang.foreign.native.threshold.power.fill=0"})
    @Benchmark
    public void heapSegmentFillUnsafe() {
        heapSegment.fill((byte) 0);
    }

    @Benchmark
    public void heapSegmentFillLoop() {
        for (long i = 0; i < heapSegment.byteSize(); i++) {
            heapSegment.set(ValueLayout.JAVA_BYTE, i, (byte) 0);
        }
    }

    @Fork(value = 3, jvmArgs = {"-Djava.lang.foreign.native.threshold.power.fill=31"})
    @Benchmark
    public void nativeSegmentFillJava() {
        nativeSegment.fill((byte) 0);
    }

    @Fork(value = 3, jvmArgs = {"-Djava.lang.foreign.native.threshold.power.fill=0"})
    @Benchmark
    public void nativeSegmentFillUnsafe() {
        nativeSegment.fill((byte) 0);
    }

    @Benchmark
    public void nativeSegmentFillLoop() {
        for (long i = 0; i < nativeSegment.byteSize(); i++) {
            nativeSegment.set(ValueLayout.JAVA_BYTE, i, (byte) 0);
        }
    }

    @Fork(value = 3, jvmArgs = {"-Djava.lang.foreign.native.threshold.power.fill=31"})
    @Benchmark
    public void unalignedSegmentFillJava() {
        unalignedSegment.fill((byte) 0);
    }

    @Fork(value = 3, jvmArgs = {"-Djava.lang.foreign.native.threshold.power.fill=0"})
    @Benchmark
    public void unalignedSegmentFillUnsafe() {
        unalignedSegment.fill((byte) 0);
    }

    @Benchmark
    public void unalignedSegmentFillLoop() {
        for (long i = 0; i < unalignedSegment.byteSize(); i++) {
            unalignedSegment.set(ValueLayout.JAVA_BYTE, i, (byte) 0);
        }
    }

}