1/*
2 * Copyright (C) 2014 University of Washington. 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 AND ITS CONTRIBUTORS "AS IS" AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
15 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
16 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
17 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
18 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
19 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
20 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
21 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
22 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
23 */
24
25#ifndef Stopwatch_h
26#define Stopwatch_h
27
28#include <cmath>
29#include <wtf/CurrentTime.h>
30#include <wtf/RefCounted.h>
31
32namespace WTF {
33
34class Stopwatch : public RefCounted<Stopwatch> {
35public:
36 static Ref<Stopwatch> create()
37 {
38 return adoptRef(*new Stopwatch());
39 }
40
41 void reset();
42 void start();
43 void stop();
44
45 double elapsedTime();
46
47 bool isActive() const { return !std::isnan(m_lastStartTime); }
48private:
49 Stopwatch() { reset(); }
50
51 double m_elapsedTime;
52 double m_lastStartTime;
53};
54
55inline void Stopwatch::reset()
56{
57 m_elapsedTime = 0.0;
58 m_lastStartTime = NAN;
59}
60
61inline void Stopwatch::start()
62{
63 ASSERT_WITH_MESSAGE(std::isnan(m_lastStartTime), "Tried to start the stopwatch, but it is already running.");
64
65 m_lastStartTime = monotonicallyIncreasingTime();
66}
67
68inline void Stopwatch::stop()
69{
70 ASSERT_WITH_MESSAGE(!std::isnan(m_lastStartTime), "Tried to stop the stopwatch, but it is not running.");
71
72 m_elapsedTime += monotonicallyIncreasingTime() - m_lastStartTime;
73 m_lastStartTime = NAN;
74}
75
76inline double Stopwatch::elapsedTime()
77{
78 if (!isActive())
79 return m_elapsedTime;
80
81 return m_elapsedTime + (monotonicallyIncreasingTime() - m_lastStartTime);
82}
83
84} // namespace WTF
85
86using WTF::Stopwatch;
87
88#endif // Stopwatch_h
89