1/*
2 * Copyright (C) 2011 Apple Inc.  All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#include "config.h"
27#include "platform/Clock.h"
28
29#include "wtf/CurrentTime.h"
30
31namespace WebCore {
32
33Clock::Clock()
34    : m_running(false)
35    , m_rate(1)
36    , m_offset(0)
37{
38    m_startTime = m_lastTime = now();
39}
40
41void Clock::setCurrentTime(double time)
42{
43    m_startTime = m_lastTime = now();
44    m_offset = time;
45}
46
47double Clock::currentTime() const
48{
49    return currentDelta() + m_offset;
50}
51
52void Clock::setPlayRate(double rate)
53{
54    m_offset += currentDelta();
55    m_lastTime = m_startTime = now();
56    m_rate = rate;
57}
58
59void Clock::start()
60{
61    if (m_running)
62        return;
63
64    m_lastTime = m_startTime = now();
65    m_running = true;
66}
67
68void Clock::stop()
69{
70    if (!m_running)
71        return;
72
73    m_offset += currentDelta();
74    m_lastTime = m_startTime = now();
75    m_running = false;
76}
77
78double Clock::now() const
79{
80    return WTF::currentTime();
81}
82
83double Clock::currentDelta() const
84{
85    if (m_running)
86        m_lastTime = now();
87    return (m_lastTime - m_startTime) * m_rate;
88}
89
90PassOwnPtr<Clock> Clock::create()
91{
92    return adoptPtr(new Clock());
93}
94
95} // namespace WebCore
96