/*

 *  Copyright (c) 2009-2011, NVIDIA Corporation

 *  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.

 *      * Neither the name of NVIDIA Corporation nor the

 *        names of its contributors may be used to endorse or promote products

 *        derived from this software without specific prior written permission.

 *

 *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND

 *  ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED

 *  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE

 *  DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY

 *  DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES

 *  (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;

 *  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND

 *  ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS

 *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */



#include "base/Timer.hpp"

#include "base/Thread.hpp"



using namespace FW;



//------------------------------------------------------------------------



F64 Timer::s_ticksToSecsCoef    = -1.0;

S64 Timer::s_prevTicks          = 0;



//------------------------------------------------------------------------



F32 Timer::end(void)

{

    S64 elapsed = getElapsedTicks();

    m_startTicks += elapsed;

    m_totalTicks += elapsed;

    return ticksToSecs(elapsed);

}



//------------------------------------------------------------------------



S64 Timer::queryTicks(void)

{

    if (!Thread::isMain())

        fail("Timers can only be used in the main thread!");



    LARGE_INTEGER ticks;

    if (!QueryPerformanceCounter(&ticks))

        failWin32Error("QueryPerformanceCounter");



    s_prevTicks = max(s_prevTicks, ticks.QuadPart);

    return s_prevTicks;

}



//------------------------------------------------------------------------



F32 Timer::ticksToSecs(S64 ticks)

{

    if (s_ticksToSecsCoef == -1.0)

    {

        LARGE_INTEGER freq;

        if (!QueryPerformanceFrequency(&freq))

            failWin32Error("QueryPerformanceFrequency");

        s_ticksToSecsCoef = max(1.0 / (F64)freq.QuadPart, 0.0);

    }



    return (F32)(ticks * s_ticksToSecsCoef);

}



//------------------------------------------------------------------------



S64 Timer::getElapsedTicks(void)

{

    S64 curr = queryTicks();

    if (m_startTicks == -1)

        m_startTicks = curr;

    return curr - m_startTicks;

}



//------------------------------------------------------------------------