/*
    * Copyright 2016 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.handler.codec.http2;
  
  import io.netty.buffer.ByteBuf;
  import io.netty.buffer.Unpooled;
  import io.netty.microbench.util.AbstractMicrobenchmark;
  import io.netty.util.AsciiString;
  import io.netty.util.internal.ConstantTimeUtils;
  import io.netty.util.internal.PlatformDependent;
  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.Setup;
  import org.openjdk.jmh.annotations.Threads;
  import org.openjdk.jmh.annotations.Warmup;
  
  import java.util.List;
  
  import static io.netty.handler.codec.http2.Http2CodecUtil.MAX_HEADER_LIST_SIZE;
  import static io.netty.handler.codec.http2.Http2CodecUtil.MAX_HEADER_TABLE_SIZE;
  
  @Threads(1)
  @Warmup(iterations = 5)
  @Measurement(iterations = 5)
  public class HpackUtilBenchmark extends AbstractMicrobenchmark {
      @Param
      public HpackHeadersSize size;
  
      private List<HpackHeader> hpackHeaders;
  
      @Setup(Level.Trial)
      public void setup() {
          hpackHeaders = HpackBenchmarkUtil.headers(size, false);
      }
  
      @Benchmark
      public int oldEquals() {
          int count = 0;
          for (int i = 0; i < hpackHeaders.size(); ++i) {
              HpackHeader hpackHeader = hpackHeaders.get(i);
              if (oldEquals(hpackHeader.name, hpackHeader.name)) {
                  ++count;
              }
          }
          return count;
      }
  
      @Benchmark
      public int newEquals() {
          int count = 0;
          for (int i = 0; i < hpackHeaders.size(); ++i) {
              HpackHeader hpackHeader = hpackHeaders.get(i);
              if (newEquals(hpackHeader.name, hpackHeader.name)) {
                  ++count;
              }
          }
          return count;
      }
  
      private static boolean oldEquals(CharSequence s1, CharSequence s2) {
          if (s1.length() != s2.length()) {
              return false;
          }
          char c = 0;
          for (int i = 0; i < s1.length(); i++) {
              c |= s1.charAt(i) ^ s2.charAt(i);
          }
          return c == 0;
      }
  
      private static boolean newEquals(CharSequence s1, CharSequence s2) {
          if (s1 instanceof AsciiString && s2 instanceof AsciiString) {
              if (s1.length() != s2.length()) {
                  return false;
              }
              AsciiString s1Ascii = (AsciiString) s1;
              AsciiString s2Ascii = (AsciiString) s2;
              return PlatformDependent.equalsConstantTime(s1Ascii.array(), s1Ascii.arrayOffset(),
                                                          s2Ascii.array(), s2Ascii.arrayOffset(), s1.length()) != 0;
          }
  
          return ConstantTimeUtils.equalsConstantTime(s1, s2) != 0;
      }
  
     static HpackEncoder newTestEncoder() {
         HpackEncoder hpackEncoder = new HpackEncoder();
         ByteBuf buf = Unpooled.buffer();
         try {
             hpackEncoder.setMaxHeaderTableSize(buf, MAX_HEADER_TABLE_SIZE);
             hpackEncoder.setMaxHeaderListSize(MAX_HEADER_LIST_SIZE);
         } catch (Http2Exception e) {
             throw new Error("max size not allowed?", e);
         } finally  {
             buf.release();
         }
         return hpackEncoder;
     }
 }