henrike@webrtc.org | f7795df | 2014-05-13 18:00:26 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2008 The WebRTC Project Authors. All rights reserved. |
| 3 | * |
| 4 | * Use of this source code is governed by a BSD-style license |
| 5 | * that can be found in the LICENSE file in the root of the source |
| 6 | * tree. An additional intellectual property rights grant can be found |
| 7 | * in the file PATENTS. All contributing project authors may |
| 8 | * be found in the AUTHORS file in the root of the source tree. |
| 9 | */ |
| 10 | |
| 11 | #ifndef WEBRTC_BASE_TIMING_H_ |
| 12 | #define WEBRTC_BASE_TIMING_H_ |
| 13 | |
| 14 | #if defined(WEBRTC_WIN) |
| 15 | #include "webrtc/base/win32.h" |
| 16 | #endif |
| 17 | |
| 18 | namespace rtc { |
| 19 | |
| 20 | class Timing { |
| 21 | public: |
| 22 | Timing(); |
| 23 | virtual ~Timing(); |
| 24 | |
| 25 | // WallTimeNow() returns the current wall-clock time in seconds, |
| 26 | // within 10 milliseconds resolution. |
| 27 | virtual double WallTimeNow(); |
| 28 | |
| 29 | // TimerNow() is like WallTimeNow(), but is monotonically |
| 30 | // increasing. It returns seconds in resolution of 10 microseconds |
| 31 | // or better. Although timer and wall-clock time have the same |
| 32 | // timing unit, they do not necessarily correlate because wall-clock |
| 33 | // time may be adjusted backwards, hence not monotonic. |
| 34 | // Made virtual so we can make a fake one. |
| 35 | virtual double TimerNow(); |
| 36 | |
| 37 | // BusyWait() exhausts CPU as long as the time elapsed is less than |
| 38 | // the specified interval in seconds. Returns the actual waiting |
| 39 | // time based on TimerNow() measurement. |
| 40 | double BusyWait(double period); |
| 41 | |
| 42 | // IdleWait() relinquishes control of CPU for specified period in |
| 43 | // seconds. It uses highest resolution sleep mechanism as possible, |
| 44 | // but does not otherwise guarantee the accuracy. Returns the |
| 45 | // actual waiting time based on TimerNow() measurement. |
| 46 | // |
| 47 | // This function is not re-entrant for an object. Create a fresh |
| 48 | // Timing object for each thread. |
| 49 | double IdleWait(double period); |
| 50 | |
| 51 | private: |
| 52 | #if defined(WEBRTC_WIN) |
| 53 | HANDLE timer_handle_; |
| 54 | #endif |
| 55 | }; |
| 56 | |
| 57 | } // namespace rtc |
| 58 | |
| 59 | #endif // WEBRTC_BASE_TIMING_H_ |