/*
    * Copyright 2020 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.util;
  
  import io.netty.microbench.util.AbstractMicrobenchmark;
  import org.openjdk.jmh.annotations.Benchmark;
  import org.openjdk.jmh.annotations.Level;
  import org.openjdk.jmh.annotations.Measurement;
  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.Threads;
  import org.openjdk.jmh.annotations.Warmup;
  import org.openjdk.jmh.infra.Blackhole;
  
  import java.util.IdentityHashMap;
  
  @Warmup(iterations = 5, time = 1)
  @Measurement(iterations = 5, time = 1)
  @State(Scope.Benchmark)
  public class DefaultAttributeMapBenchmark extends AbstractMicrobenchmark {
  
      @Param({ "8", "32", "128" })
      private int keyCount;
      private AttributeKey<Integer>[] keys;
      private IdentityHashMap<AttributeKey<Integer>, Attribute<Integer>> identityHashMap;
      private DefaultAttributeMap attributes;
  
      @State(Scope.Thread)
      public static class KeySequence {
  
          long nextKey;
  
          @Setup(Level.Iteration)
          public void reset() {
              nextKey = 0;
          }
  
          public long next() {
              return nextKey++;
          }
      }
  
      @Setup
      public void init() {
          if (Integer.bitCount(keyCount) != 1) {
              throw new AssertionError("keyCount should cbe a power of 2");
          }
          attributes = new DefaultAttributeMap();
          keys = new AttributeKey[keyCount];
          identityHashMap = new IdentityHashMap<AttributeKey<Integer>, Attribute<Integer>>(keyCount);
          for (int i = 0; i < keyCount; i++) {
              final AttributeKey<Integer> key = AttributeKey.valueOf(Integer.toString(i));
              keys[i] = key;
              final Attribute<Integer> attribute = attributes.attr(key);
              identityHashMap.put(key, attribute);
          }
      }
  
      @Benchmark
      @Threads(3)
      public Attribute<Integer> nextAttributeIdentityHashMap(KeySequence sequence) {
          long next = sequence.next();
          AttributeKey<Integer>[] keys = this.keys;
          AttributeKey<Integer> key = keys[(int) (next & keys.length - 1)];
          return identityHashMap.get(key);
      }
  
      @Benchmark
      @Threads(3)
      public boolean hasAttributeIdentityHashMap(KeySequence sequence) {
          long next = sequence.next();
          AttributeKey<Integer>[] keys = this.keys;
          AttributeKey<Integer> key = keys[(int) (next & keys.length - 1)];
          return identityHashMap.containsKey(key);
      }
  
      @Benchmark
      @Threads(3)
      public void mixedAttributeIdentityHashMap(KeySequence sequence, Blackhole hole) {
          long next = sequence.next();
          AttributeKey<Integer>[] keys = this.keys;
          AttributeKey<Integer> key = keys[(int) (next & keys.length - 1)];
          if (next % 2 == 0) {
              hole.consume(identityHashMap.get(key));
         } else {
             hole.consume(identityHashMap.containsKey(key));
         }
     }
 
     @Benchmark
     @Threads(3)
     public Attribute<Integer> nextAttributeAttributeMap(KeySequence sequence) {
         long next = sequence.next();
         AttributeKey<Integer>[] keys = this.keys;
         AttributeKey<Integer> key = keys[(int) (next & keys.length - 1)];
         return attributes.attr(key);
     }
 
     @Benchmark
     @Threads(3)
     public boolean nextHasAttributeAttributeMap(KeySequence sequence) {
         long next = sequence.next();
         AttributeKey<Integer>[] keys = this.keys;
         AttributeKey<Integer> key = keys[(int) (next & keys.length - 1)];
         return attributes.hasAttr(key);
     }
 
     @Benchmark
     @Threads(3)
     public void mixedAttributeAttributeMap(KeySequence sequence, Blackhole hole) {
         long next = sequence.next();
         AttributeKey<Integer>[] keys = this.keys;
         AttributeKey<Integer> key = keys[(int) (next & keys.length - 1)];
         if (next % 2 == 0) {
             hole.consume(attributes.attr(key));
         } else {
             hole.consume(attributes.hasAttr(key));
         }
     }
 }