package jdk.test;

import org.openjdk.jmh.annotations.Benchmark;
import org.openjdk.jmh.annotations.BenchmarkMode;
import org.openjdk.jmh.annotations.Fork;
import org.openjdk.jmh.annotations.Level;
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.util.concurrent.TimeUnit;

@BenchmarkMode(Mode.AverageTime)
@Fork(3)
@Warmup(iterations = 10)
@Measurement(iterations = 20)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
public class AppendNTest {


    @State(Scope.Benchmark)
    public static class Data {

        @Param({"0", "1", "5", "10", "20"})
        public int size;

        String solid;

        final StringBuilder sb = new StringBuilder(64);

        @Setup(Level.Invocation)
        public void beforeInvocation() {
            sb.setLength(0);
        }

        @Setup
        public void setup() {
            solid = "";
            for (int i = size; i > 0; --i) {
                solid += '@';
            }
        }
    }

    @Benchmark
    public void test_0_New(Data d) {
        d.sb.appendN('@', d.size);
    }

    @Benchmark
    public void test_1_Old(Data d) {
        for (int i = d.size; i > 0; --i) {
            d.sb.append('@');
        }
    }

    @Benchmark
    public void test_2_Solid(Data d) {
        d.sb.append(d.solid);
    }

    @Benchmark
    public void test_3_Repeat(Data d) {
        d.sb.append(CharSequence.repetitions('@', d.size));
    }
}