1/*
2 * Copyright (C) 2006 Apple Inc. All rights reserved.
3 * Copyright (C) 2008 Google Inc. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are
7 * met:
8 *
9 * * Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * * Redistributions in binary form must reproduce the above
12 * copyright notice, this list of conditions and the following disclaimer
13 * in the documentation and/or other materials provided with the
14 * distribution.
15 * * Neither the name of Google Inc. nor the names of its
16 * contributors may be used to endorse or promote products derived from
17 * this software without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
21 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
22 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
23 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
24 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
25 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
27 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
29 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 */
31
32#ifndef CurrentTime_h
33#define CurrentTime_h
34
35#include <chrono>
36#include <time.h>
37
38namespace WTF {
39
40// Returns the current UTC time in seconds, counted from January 1, 1970.
41// Precision varies depending on platform but is usually as good or better
42// than a millisecond.
43// Use this function only if wall clock time is needed. For elapsed time
44// measurement use monotonicallyIncreasingTime() instead.
45WTF_EXPORT_PRIVATE double currentTime();
46
47// Same thing, in milliseconds.
48inline double currentTimeMS()
49{
50 return currentTime() * 1000.0;
51}
52
53// Provides a monotonically increasing time in seconds since an arbitrary point in the past.
54// On unsupported platforms, this function only guarantees the result will be non-decreasing.
55// Result of this function increases monotonically even when clock time goes back due to
56// NTP or manual adjustments, so it is better suited for elapsed time measurement.
57WTF_EXPORT_PRIVATE double monotonicallyIncreasingTime();
58
59inline double monotonicallyIncreasingTimeMS()
60{
61 return monotonicallyIncreasingTime() * 1000.0;
62}
63
64// Returns the current CPU time of the current thread.
65// Precision varies depending on platform but is usually as good or better
66// than a millisecond.
67WTF_EXPORT_PRIVATE std::chrono::microseconds currentCPUTime();
68
69} // namespace WTF
70
71using WTF::currentTime;
72using WTF::currentTimeMS;
73using WTF::monotonicallyIncreasingTime;
74using WTF::monotonicallyIncreasingTimeMS;
75using WTF::currentCPUTime;
76
77#endif // CurrentTime_h
78