/*
    * Copyright 2023 The Netty Project
    *
    * The Netty Project licenses this file to you 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:
    *
    *   https://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 io.netty.buffer;
  
  import io.netty.microbench.util.AbstractMicrobenchmark;
  import org.openjdk.jmh.annotations.Benchmark;
  import org.openjdk.jmh.annotations.BenchmarkMode;
  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.TearDown;
  import org.openjdk.jmh.annotations.Warmup;
  
  import java.util.concurrent.TimeUnit;
  
  @State(Scope.Benchmark)
  @BenchmarkMode(Mode.AverageTime)
  @OutputTimeUnit(TimeUnit.NANOSECONDS)
  @Warmup(iterations = 10, time = 400, timeUnit = TimeUnit.MILLISECONDS)
  @Measurement(iterations = 5, time = 200, timeUnit = TimeUnit.MILLISECONDS)
  public class ByteBufZeroingBenchmark extends AbstractMicrobenchmark {
  
      @Param({
              "1",
              "2",
              "3",
              "4",
              "7",
              "8",
              "15",
              "64",
              "65",
              "1024",
      })
      private int bytes = 1024;
      @Param({
              "true",
              "false",
      })
      private boolean direct;
      @Param({
              "true",
              "false",
      })
      private boolean pooled;
      @Param({
              "false",
      })
      public String checkAccessible;
  
      @Param({
              "false",
      })
      public String checkBounds;
      @Param({
              "0",
              "1",
      })
      public int startOffset;
      private ByteBuf buffer;
      private int offset;
  
      @Setup
      public void setup() {
          System.setProperty("io.netty.buffer.checkAccessible", checkAccessible);
          System.setProperty("io.netty.buffer.checkBounds", checkBounds);
          ByteBufAllocator allocator = pooled? PooledByteBufAllocator.DEFAULT : UnpooledByteBufAllocator.DEFAULT;
          int capacityRequired = startOffset + bytes;
          offset = 0;
          buffer = direct? alignedDirectAllocation(allocator, capacityRequired, 8) :
                  allocator.heapBuffer(capacityRequired, capacityRequired);
          if (startOffset > 0) {
              offset += startOffset;
          }
      }
  
      private ByteBuf alignedDirectAllocation(ByteBufAllocator allocator, int bytes, final int alignment) {
          ByteBuf buffer = allocator.directBuffer(bytes + alignment, bytes + alignment);
          final long address = buffer.memoryAddress();
          final int remainder = (int) address % alignment;
          final int nextAlignedOffset = alignment - remainder;
          this.offset = nextAlignedOffset;
         return buffer;
     }
 
     @Benchmark
     public ByteBuf setZero() {
         final ByteBuf buffer = this.buffer;
         buffer.setZero(offset, bytes);
         return buffer;
     }
 
     @Benchmark
     public ByteBuf setBytes() {
         final ByteBuf buffer = this.buffer;
         final int offset = this.offset;
         for (int i = 0; i < bytes; i++) {
             buffer.setByte(offset + i, 0);
         }
         return buffer;
     }
 
     @TearDown
     public void teardown() {
         buffer.release();
     }
 
 }