1 /* 2 * Copyright (c) 2013 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_SYSTEM_WRAPPERS_INTERFACE_CLOCK_H_ 12 #define WEBRTC_SYSTEM_WRAPPERS_INTERFACE_CLOCK_H_ 13 14 #include "webrtc/system_wrappers/interface/rw_lock_wrapper.h" 15 #include "webrtc/system_wrappers/interface/scoped_ptr.h" 16 #include "webrtc/typedefs.h" 17 18 namespace webrtc { 19 20 // January 1970, in NTP seconds. 21 const uint32_t kNtpJan1970 = 2208988800UL; 22 23 // Magic NTP fractional unit. 24 const double kMagicNtpFractionalUnit = 4.294967296E+9; 25 26 // A clock interface that allows reading of absolute and relative timestamps. 27 class Clock { 28 public: ~Clock()29 virtual ~Clock() {} 30 31 // Return a timestamp in milliseconds relative to some arbitrary source; the 32 // source is fixed for this clock. 33 virtual int64_t TimeInMilliseconds() const = 0; 34 35 // Return a timestamp in microseconds relative to some arbitrary source; the 36 // source is fixed for this clock. 37 virtual int64_t TimeInMicroseconds() const = 0; 38 39 // Retrieve an NTP absolute timestamp in seconds and fractions of a second. 40 virtual void CurrentNtp(uint32_t& seconds, uint32_t& fractions) const = 0; 41 42 // Retrieve an NTP absolute timestamp in milliseconds. 43 virtual int64_t CurrentNtpInMilliseconds() const = 0; 44 45 // Converts an NTP timestamp to a millisecond timestamp. 46 static int64_t NtpToMs(uint32_t seconds, uint32_t fractions); 47 48 // Returns an instance of the real-time system clock implementation. 49 static Clock* GetRealTimeClock(); 50 }; 51 52 class SimulatedClock : public Clock { 53 public: 54 explicit SimulatedClock(int64_t initial_time_us); 55 56 virtual ~SimulatedClock(); 57 58 // Return a timestamp in milliseconds relative to some arbitrary source; the 59 // source is fixed for this clock. 60 virtual int64_t TimeInMilliseconds() const OVERRIDE; 61 62 // Return a timestamp in microseconds relative to some arbitrary source; the 63 // source is fixed for this clock. 64 virtual int64_t TimeInMicroseconds() const OVERRIDE; 65 66 // Retrieve an NTP absolute timestamp in milliseconds. 67 virtual void CurrentNtp(uint32_t& seconds, 68 uint32_t& fractions) const OVERRIDE; 69 70 // Converts an NTP timestamp to a millisecond timestamp. 71 virtual int64_t CurrentNtpInMilliseconds() const OVERRIDE; 72 73 // Advance the simulated clock with a given number of milliseconds or 74 // microseconds. 75 void AdvanceTimeMilliseconds(int64_t milliseconds); 76 void AdvanceTimeMicroseconds(int64_t microseconds); 77 78 private: 79 int64_t time_us_; 80 scoped_ptr<RWLockWrapper> lock_; 81 }; 82 83 }; // namespace webrtc 84 85 #endif // WEBRTC_SYSTEM_WRAPPERS_INTERFACE_CLOCK_H_ 86