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   /*
    * Copyright 2018 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 io.netty.util.ByteProcessor;
  
  import org.openjdk.jmh.annotations.Benchmark;
  import org.openjdk.jmh.annotations.Measurement;
  import org.openjdk.jmh.annotations.Param;
  import org.openjdk.jmh.annotations.Setup;
  import org.openjdk.jmh.annotations.TearDown;
  import org.openjdk.jmh.annotations.Warmup;
  
  import static io.netty.buffer.Unpooled.EMPTY_BUFFER;
  import static io.netty.buffer.Unpooled.wrappedBuffer;
  
  import java.util.ArrayList;
  import java.util.List;
  import java.util.concurrent.TimeUnit;
  
  @Warmup(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS)
  @Measurement(iterations = 10, time = 1, timeUnit = TimeUnit.SECONDS)
  public class CompositeByteBufSequentialBenchmark extends AbstractMicrobenchmark {
  
      public enum ByteBufType {
          SMALL_CHUNKS {
              @Override
              ByteBuf newBuffer(int length) {
                  return newBufferSmallChunks(length);
              }
          },
          LARGE_CHUNKS {
              @Override
              ByteBuf newBuffer(int length) {
                  return newBufferLargeChunks(length);
              }
          };
          abstract ByteBuf newBuffer(int length);
      }
  
      @Param({ "8", "64", "1024", "10240", "102400", "1024000" })
      public int size;
  
      @Param
      public ByteBufType bufferType;
  
      private ByteBuf buffer;
  
      @Setup
      public void setup() {
          buffer = bufferType.newBuffer(size);
      }
  
      @TearDown
      public void teardown() {
          buffer.release();
      }
  
      private static final ByteProcessor TEST_PROCESSOR = new ByteProcessor() {
          @Override
          public boolean process(byte value) throws Exception {
              return value == 'b'; // false
          }
      };
  
      @Benchmark
      public int forEachByte() {
          buffer.setIndex(0, buffer.capacity());
          buffer.forEachByte(TEST_PROCESSOR);
          return buffer.forEachByteDesc(TEST_PROCESSOR);
      }
  
      @Benchmark
      public int sequentialWriteAndRead() {
          buffer.clear();
          for (int i = 0, l = buffer.writableBytes(); i < l; i++) {
              buffer.writeByte('a');
          }
          for (int i = 0, l = buffer.readableBytes(); i < l; i++) {
              if (buffer.readByte() == 'b') {
                  return -1;
              }
          }
          return 1;
      }
 
     private static ByteBuf newBufferSmallChunks(int length) {
 
         List<ByteBuf> buffers = new ArrayList<ByteBuf>(((length + 1) / 45) * 19);
         for (int i = 0; i < length + 45; i += 45) {
             for (int j = 1; j <= 9; j++) {
                 buffers.add(EMPTY_BUFFER);
                 buffers.add(wrappedBuffer(new byte[j]));
             }
             buffers.add(EMPTY_BUFFER);
         }
 
         ByteBuf buffer = wrappedBuffer(Integer.MAX_VALUE, buffers.toArray(new ByteBuf[0]));
 
         // Truncate to the requested capacity.
         return buffer.capacity(length).writerIndex(0);
     }
 
     private static ByteBuf newBufferLargeChunks(int length) {
 
         List<ByteBuf> buffers = new ArrayList<ByteBuf>((length + 1) / 512);
         for (int i = 0; i < length + 1536; i += 1536) {
             buffers.add(wrappedBuffer(new byte[512]));
             buffers.add(EMPTY_BUFFER);
             buffers.add(wrappedBuffer(new byte[1024]));
         }
 
         ByteBuf buffer = wrappedBuffer(Integer.MAX_VALUE, buffers.toArray(new ByteBuf[0]));
 
         // Truncate to the requested capacity.
         return buffer.capacity(length).writerIndex(0);
     }
 }