third_party/WebKit/Source/platform/Clock.cpp

   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
  31 namespace blink {
  32
  33 Clock::Clock()
  34     : m_running(false)
  35     , m_rate(1)
  36     , m_offset(0)
  37 {
  38     m_startTime = m_lastTime = now();
  39 }
  40
  41 void Clock::setCurrentTime(double time)
  42 {
  43     m_startTime = m_lastTime = now();
  44     m_offset = time;
  45 }
  46
  47 double Clock::currentTime() const
  48 {
  49     return currentDelta() + m_offset;
  50 }
  51
  52 void Clock::setPlayRate(double rate)
  53 {
  54     m_offset += currentDelta();
  55     m_lastTime = m_startTime = now();
  56     m_rate = rate;
  57 }
  58
  59 void Clock::start()
  60 {
  61     if (m_running)
  62         return;
  63
  64     m_lastTime = m_startTime = now();
  65     m_running = true;
  66 }
  67
  68 void 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
  78 double Clock::now() const
  79 {
  80     return WTF::currentTime();
  81 }
  82
  83 double Clock::currentDelta() const
  84 {
  85     if (m_running)
  86         m_lastTime = now();
  87     return (m_lastTime - m_startTime) * m_rate;
  88 }
  89
  90 PassOwnPtr<Clock> Clock::create()
  91 {
  92     return adoptPtr(new Clock());
  93 }
  94
  95 } // namespace blink