samples/angle/sample_util/win32/Win32Timer.cpp


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//
// Copyright (c) 2014 The ANGLE Project Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//

#include "win32/Win32Timer.h"

Win32Timer::Win32Timer()
    : mRunning(0),
      mStartTime(0),
      mStopTime(0)
{
}

void Win32Timer::start()
{
    LARGE_INTEGER frequency;
    QueryPerformanceFrequency(&frequency);
    mFrequency = frequency.QuadPart;

    LARGE_INTEGER curTime;
    QueryPerformanceCounter(&curTime);
    mStartTime = curTime.QuadPart;

    mRunning = true;
}

void Win32Timer::stop()
{
    LARGE_INTEGER curTime;
    QueryPerformanceCounter(&curTime);
    mStopTime = curTime.QuadPart;

    mRunning = false;
}

double Win32Timer::getElapsedTime() const
{
    LONGLONG endTime;
    if (mRunning)
    {
        LARGE_INTEGER curTime;
        QueryPerformanceCounter(&curTime);
        endTime = curTime.QuadPart;
    }
    else
    {
        endTime = mStopTime;
    }

    return static_cast<double>(endTime - mStartTime) / mFrequency;
}