Cpp_Timer.h

#pragma once

#include <chrono>
#include <functional>
#include <string>
#include <iostream>
#include <cstdint>

class DCTimer
{
    using Clock    = std::chrono::high_resolution_clock;
    using TimeUnit = std::chrono::milliseconds;

public:

    DCTimer(QString const &                      msg           = "",
            bool                                 showOnDestroy = false,
            std::function<bool(int32_t)> const & fn            = nullptr)
        : m_msg(msg)
        , m_showOnDestroy(showOnDestroy)
        , m_fn(fn) {}

    DCTimer(QString                      const & msg = "",
            std::function<bool(int32_t)> const & fn  = nullptr)
        : DCTimer(msg, true, fn) {}

    ~DCTimer()
    {
        if (m_showOnDestroy && runUserFn())
            showElapsed();
    }

    inline void reset(QString const & msg = "")
    {
        m_msg   = msg!="" ? msg : ( m_msg + "_" + (m_resetCount++) );
        m_begin = Clock::now();
    }

    inline void showAndReset(QString const & msg = "")
    {
        if (runUserFn())
            showElapsed();

        reset(msg);
    }

    inline int32_t getTime() const
    {
        return std::chrono::duration_cast<TimeUnit>( Clock::now() - m_begin ).count();
    }

    inline void showElapsed() const
    {
        std::cout << "[DCTimer] => (" << getTime() << " ms) : " << m_msg;
    }

private:

    inline bool runUserFn()
    {
        return m_fn ? m_fn(getTime()) : true;
    }

    Clock::time_point            m_begin         = Clock::now();
    QString                      m_msg           = "";
    bool                         m_showOnDestroy = true;
    std::function<bool(int32_t)> m_fn            = nullptr;

    int32_t m_resetCount = 1;
};