stopwatch.h

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#pragma once

#include <ros/time.h>
#include <ros/console.h>

namespace mapviz
{
/* This class measures the wall time of an interval and keeps track of
 * the number of intervals, the average duration, and the maximum
 * duration.  This is used to provide some simple measurements to keep
 * an eye on performance.
 */
class Stopwatch
{
 public:
  Stopwatch()
    :
    count_(0)
  {
  }

  /* Start measuring a new time interval. */
  void start()
  {
    start_ = ros::WallTime::now();
  }

  /* End the current time interval and update the measurements.
   * Behavior is undefined if start() was not called prior to this.
   */
  void stop()
  {
    ros::WallDuration dt = ros::WallTime::now() - start_;
    count_ += 1;
    total_time_ += dt;
    max_time_ = std::max(max_time_, dt);
  }

  /* Return the number of intervals measured. */
  int count() const { return count_; }

  /* Returns the longest observed duration. */
  ros::WallDuration maxTime() const { return max_time_; }

  /* Returns the average duration spent in the interval. */
  ros::WallDuration avgTime() const
  {
    if (count_)
    {
      return total_time_*(1.0/count_);
    }
    else
    {
      return ros::WallDuration();
    }
  }

  /* Print measurement info to the ROS console. */
  void printInfo(const std::string &name) const
  {
    if (count_)
    {
      ROS_INFO("%s -- calls: %d, avg time: %.2fms, max time: %.2fms",
               name.c_str(),
               count_,
               avgTime().toSec()*1000.0,
               maxTime().toSec()*1000.0);
    }
    else
    {
      ROS_INFO("%s -- calls: %d, avg time: --ms, max time: --ms",
               name.c_str(),
               count_);
    }
  }

 private:
  int count_;
  ros::WallDuration total_time_;
  ros::WallDuration max_time_;

  ros::WallTime start_;
};  // class PluginInstrumentation
}  // namespace mapviz