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 | |
38 | namespace 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. |
45 | WTF_EXPORT_PRIVATE double currentTime(); |
46 | |
47 | // Same thing, in milliseconds. |
48 | inline 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. |
57 | WTF_EXPORT_PRIVATE double monotonicallyIncreasingTime(); |
58 | |
59 | inline 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. |
67 | WTF_EXPORT_PRIVATE std::chrono::microseconds currentCPUTime(); |
68 | |
69 | } // namespace WTF |
70 | |
71 | using WTF::currentTime; |
72 | using WTF::currentTimeMS; |
73 | using WTF::monotonicallyIncreasingTime; |
74 | using WTF::monotonicallyIncreasingTimeMS; |
75 | using WTF::currentCPUTime; |
76 | |
77 | #endif // CurrentTime_h |
78 | |