ClockGeneric.cpp

/*
 * Copyright (C) 2011 Apple Inc.  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 "config.h"
#include "ClockGeneric.h"

#include "FloatConversion.h"
#include <wtf/CurrentTime.h>

using namespace WebCore;

ClockGeneric::ClockGeneric()
    : m_running(false)
    , m_rate(1)
    , m_offset(0)
{
    m_startTime = m_lastTime = now();
}

void ClockGeneric::setCurrentTime(float time)
{
    m_startTime = m_lastTime = now();
    m_offset = time;
}

float ClockGeneric::currentTime() const
{
    if (m_running)
        m_lastTime = now();
    float time = narrowPrecisionToFloat(((m_lastTime - m_startTime) * m_rate) + m_offset);
    return time;
}

void ClockGeneric::setPlayRate(float rate)
{
    m_offset = now();
    m_lastTime = m_startTime = now();
    m_rate = rate;
}

void ClockGeneric::start()
{
    if (m_running)
        return;

    m_lastTime = m_startTime = now();
    m_running = true;
}

void ClockGeneric::stop()
{
    if (!m_running)
        return;

    m_offset = now();
    m_lastTime = m_startTime = now();
    m_running = false;
}

double ClockGeneric::now() const
{
    return WTF::currentTime();
}