1 /* 2 * libjingle 3 * Copyright 2008, Google Inc. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright notice, 9 * this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright notice, 11 * this list of conditions and the following disclaimer in the documentation 12 * and/or other materials provided with the distribution. 13 * 3. The name of the author may not be used to endorse or promote products 14 * derived from this software without specific prior written permission. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 17 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 18 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO 19 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 20 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 21 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 22 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 23 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 24 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 25 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 28 #ifndef TALK_BASE_TIMING_H_ 29 #define TALK_BASE_TIMING_H_ 30 31 #if defined(WIN32) 32 #include "talk/base/win32.h" 33 #endif 34 35 namespace talk_base { 36 37 class Timing { 38 public: 39 Timing(); 40 virtual ~Timing(); 41 42 // WallTimeNow() returns the current wall-clock time in seconds, 43 // within 10 milliseconds resolution. 44 virtual double WallTimeNow(); 45 46 // TimerNow() is like WallTimeNow(), but is monotonically 47 // increasing. It returns seconds in resolution of 10 microseconds 48 // or better. Although timer and wall-clock time have the same 49 // timing unit, they do not necessarily correlate because wall-clock 50 // time may be adjusted backwards, hence not monotonic. 51 // Made virtual so we can make a fake one. 52 virtual double TimerNow(); 53 54 // BusyWait() exhausts CPU as long as the time elapsed is less than 55 // the specified interval in seconds. Returns the actual waiting 56 // time based on TimerNow() measurement. 57 double BusyWait(double period); 58 59 // IdleWait() relinquishes control of CPU for specified period in 60 // seconds. It uses highest resolution sleep mechanism as possible, 61 // but does not otherwise guarantee the accuracy. Returns the 62 // actual waiting time based on TimerNow() measurement. 63 // 64 // This function is not re-entrant for an object. Create a fresh 65 // Timing object for each thread. 66 double IdleWait(double period); 67 68 private: 69 #if defined(WIN32) 70 HANDLE timer_handle_; 71 #endif 72 }; 73 74 } // namespace talk_base 75 76 #endif // TALK_BASE_TIMING_H_ 77
