Timer.h

/*****************************************************************************
 * @file: Timer.h
 * @brief:
 *
 * Copyright (c) 2022 O-Net Communications Inc.
 ****************************************************************************/

#pragma once

#include <chrono>

namespace cppbase {

using ns = std::chrono::nanoseconds;
using us = std::chrono::microseconds;
using ms = std::chrono::milliseconds;
using s = std::chrono::seconds;
using m = std::chrono::minutes;
using h = std::chrono::hours;

template <typename DurationType>
class Timer;
using TimerNs = Timer<ns>;
using TimerUs = Timer<us>;
using TimerMs = Timer<ms>;
using TimerS = Timer<s>;
using TimerM = Timer<m>;
using TimerH = Timer<h>;

template <typename DurationType = us>
class Timer
{
public:
    Timer() : m_started(true), m_last(std::chrono::steady_clock::now()) {}

    void Start()
    {
        m_started = true;
        m_last = std::chrono::steady_clock::now();
    }
    void Stop() { m_started = false; }

    bool IsRunning() const { return m_started; }
    typename DurationType::rep Elapsed() const
    {
        if (!m_started)
            return 0;

        auto elapsed =
            std::chrono::duration_cast<DurationType>(std::chrono::steady_clock::now() - m_last);
        return elapsed.count();
    }

private:
    bool m_started;
    std::chrono::steady_clock::time_point m_last;
};

}  // namespace cppbase