/*

 * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)

 *

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. 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.

 *

 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``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 APPLE COMPUTER, INC. OR

 * CONTRIBUTORS 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 "fpstimer.h"

#include <QDateTime>

#include <QTimerEvent>

// We save a maximum of 10000 frames, and purge 2000 at a time

#define MAX_FRAMES_SAVED 10000

#define FRAMES_TO_PURGE_WHEN_FULL 2000

// 60 FPS

#define FPS_MEASURE_INTERVAL 1000 / 60

FpsTimer::FpsTimer(QObject* parent)

        : QObject(parent)

{

}

int FpsTimer::numFrames(int spanMillis)

{

    const QTime now = QTime::currentTime();

    int count = 0;

    for (int i = m_frames.length() - 1; i >= 0; --i, ++count) {

        int msecs = m_frames[i].msecsTo(now);

        if (msecs < 0)

            msecs += 24 * 60 * 60 * 1000;

        if (msecs > spanMillis)

            break;

    }

    return count;

}

void FpsTimer::start()

{

    m_timer = startTimer(FPS_MEASURE_INTERVAL);

}

void FpsTimer::stop()

{

    killTimer(m_timer);

    m_frames.clear();

}

void FpsTimer::timerEvent(QTimerEvent* event)

{

    if (event->timerId() !=  m_timer)

        return;

    m_frames.append(QTime::currentTime());

    if (m_frames.length() > MAX_FRAMES_SAVED)

        m_frames.erase(m_frames.begin(), m_frames.begin() + FRAMES_TO_PURGE_WHEN_FULL);

}