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_INCLUDE_CLOCK_H_
12#define WEBRTC_SYSTEM_WRAPPERS_INCLUDE_CLOCK_H_
13
14#include "webrtc/base/scoped_ptr.h"
15#include "webrtc/system_wrappers/include/rw_lock_wrapper.h"
16#include "webrtc/typedefs.h"
17
18namespace webrtc {
19
20// January 1970, in NTP seconds.
21const uint32_t kNtpJan1970 = 2208988800UL;
22
23// Magic NTP fractional unit.
24const double kMagicNtpFractionalUnit = 4.294967296E+9;
25
26// A clock interface that allows reading of absolute and relative timestamps.
27class Clock {
28 public:
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
52class SimulatedClock : public Clock {
53 public:
54  explicit SimulatedClock(int64_t initial_time_us);
55
56  ~SimulatedClock() override;
57
58  // Return a timestamp in milliseconds relative to some arbitrary source; the
59  // source is fixed for this clock.
60  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  int64_t TimeInMicroseconds() const override;
65
66  // Retrieve an NTP absolute timestamp in milliseconds.
67  void CurrentNtp(uint32_t& seconds, uint32_t& fractions) const override;
68
69  // Converts an NTP timestamp to a millisecond timestamp.
70  int64_t CurrentNtpInMilliseconds() const override;
71
72  // Advance the simulated clock with a given number of milliseconds or
73  // microseconds.
74  void AdvanceTimeMilliseconds(int64_t milliseconds);
75  void AdvanceTimeMicroseconds(int64_t microseconds);
76
77 private:
78  int64_t time_us_;
79  rtc::scoped_ptr<RWLockWrapper> lock_;
80};
81
82};  // namespace webrtc
83
84#endif  // WEBRTC_SYSTEM_WRAPPERS_INCLUDE_CLOCK_H_
85