stop_watch.hpp

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//============================================================================
// vSMC/include/vsmc/utility/stop_watch.hpp
//----------------------------------------------------------------------------
//                         vSMC: Scalable Monte Carlo
//----------------------------------------------------------------------------
// Copyright (c) 2013-2016, Yan Zhou
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
//   Redistributions of source code must retain the above copyright notice,
//   this list of conditions and the following disclaimer.
//
//   Redistributions in binary form must reproduce the above copyright notice,
//   this list of conditions and the following disclaimer in the documentation
//   and/or other materials provided with the distribution.
//
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// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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//============================================================================

#ifndef VSMC_UTILITY_STOP_WATCH_HPP
#define VSMC_UTILITY_STOP_WATCH_HPP

#include <vsmc/internal/common.hpp>

#ifndef VSMC_STOP_WATCH_CLOCK_TYPE
#define VSMC_STOP_WATCH_CLOCK_TYPE std::chrono::high_resolution_clock
#endif

namespace vsmc
{

template <typename WatchType>
class StopWatchGuard
{
    public:
    using watch_type = WatchType;

    StopWatchGuard(watch_type &watch, bool start = true)
        : start_(start), watch_(watch)
    {
        if (start_)
            watch_.start();
    }

    ~StopWatchGuard()
    {
        if (start_)
            watch_.stop();
    }

    private:
    const bool start_;
    watch_type &watch_;
}; // class StopWatchGuard

template <typename ClockType>
class StopWatchClockAdapter
{
    public:
    using clock_type = ClockType;

    StopWatchClockAdapter() : elapsed_(0), running_(false) { reset(); }

    bool running() const { return running_; }

    bool start()
    {
        if (running_)
            return false;

        running_ = true;
        start_time_ = clock_type::now();

        return true;
    }

    bool stop()
    {
        if (!running_)
            return false;

        typename clock_type::time_point stop_time = clock_type::now();
        elapsed_ += stop_time - start_time_;
        running_ = false;

        return true;
    }

    void reset()
    {
        start();
        elapsed_ = typename clock_type::duration(0);
        running_ = false;
    }

    double nanoseconds() const
    {
        return std::chrono::duration_cast<
                   std::chrono::duration<double, std::nano>>(elapsed_)
            .count();
    }

    double microseconds() const
    {
        return std::chrono::duration_cast<
                   std::chrono::duration<double, std::micro>>(elapsed_)
            .count();
    }

    double milliseconds() const
    {
        return std::chrono::duration_cast<
                   std::chrono::duration<double, std::milli>>(elapsed_)
            .count();
    }

    double seconds() const
    {
        return std::chrono::duration_cast<
                   std::chrono::duration<double, std::ratio<1>>>(elapsed_)
            .count();
    }

    double minutes() const
    {
        return std::chrono::duration_cast<
                   std::chrono::duration<double, std::ratio<60>>>(elapsed_)
            .count();
    }

    double hours() const
    {
        return std::chrono::duration_cast<
                   std::chrono::duration<double, std::ratio<3600>>>(elapsed_)
            .count();
    }

    private:
    typename clock_type::duration elapsed_;
    typename clock_type::time_point start_time_;
    bool running_;
}; // class StopWatchClockAdapter

using StopWatch = StopWatchClockAdapter<VSMC_STOP_WATCH_CLOCK_TYPE>;

} // namespace vsmc

#endif // VSMC_UTILITY_STOP_WATCH_HPP