waveform.h

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/*
 * Copyright 2011 Google Inc.
 *
 * Licensed 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
 *
 *      http:///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.
 */


#ifndef PAGESPEED_KERNEL_BASE_WAVEFORM_H_
#define PAGESPEED_KERNEL_BASE_WAVEFORM_H_

#include <utility>                      

#include "pagespeed/kernel/base/basictypes.h"
#include "pagespeed/kernel/base/scoped_ptr.h"
#include "pagespeed/kernel/base/string_util.h"

namespace net_instaweb {

class AbstractMutex;
class MessageHandler;
class ThreadSystem;
class Timer;
class UpDownCounter;
class Writer;

class Waveform {
 public:
  Waveform(ThreadSystem* thread_system, Timer* timer, int capacity,
           UpDownCounter* metric);

  void Clear();
  double Average();
  double Maximum();
  double Minimum();
  int Size();

  void Add(double value);

  void AddDelta(double delta);

  static void RenderHeader(Writer* writer, MessageHandler* handler);

  void Render(const StringPiece& title, const StringPiece& label,
              Writer* writer, MessageHandler* handler);

 private:
  typedef std::pair<int64, double> TimeValue;

  TimeValue* GetSample(int index); 
  void AddHelper(double value); 

  Timer* timer_;
  int capacity_;
  scoped_array<TimeValue> samples_;
  int start_index_;
  int size_;
  int64 first_sample_timestamp_us_;
  double total_since_clear_;
  double min_;
  double max_;
  double previous_value_;
  scoped_ptr<AbstractMutex> mutex_; 

  UpDownCounter* metric_;

  
};

}  

#endif