// TortoiseSVN - a Windows shell extension for easy version control

// Copyright (C) 2007-2007, 2021 - TortoiseSVN

// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software Foundation,
// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
//
#pragma once

///////////////////////////////////////////////////////////////
//
// CHighResClock
//
//      high resolution clock for performance measurement.
//      Depending on the hardware it will provide µsec
//      resolution and accuracy.
//
//      May not be available on all machines.
//
///////////////////////////////////////////////////////////////

class CHighResClock
{
private:
    LARGE_INTEGER start;
    LARGE_INTEGER taken;

public:
    // construction (starts measurement) / destruction

    CHighResClock()
    {
        taken.QuadPart = 0;
        Start();
    }

    ~CHighResClock()
    {
    }

    // (re-start)

    void Start()
    {
        QueryPerformanceCounter(&start);
    }

    // set "taken" to time since last Start()

    void Stop()
    {
        QueryPerformanceCounter(&taken);
        taken.QuadPart -= start.QuadPart;
    }

    // time in microseconds between last Start() and last Stop()

    DWORD GetMusecsTaken() const
    {
        LARGE_INTEGER frequency;
        QueryPerformanceFrequency(&frequency);
        return static_cast<DWORD>((taken.QuadPart * 1000000) / frequency.QuadPart);
    }
};
