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/*
* Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#ifndef SYSTEM_WRAPPERS_INCLUDE_CLOCK_H_
#define SYSTEM_WRAPPERS_INCLUDE_CLOCK_H_
#include <stdint.h>
#include <memory>
#include "rtc_base/synchronization/rw_lock_wrapper.h"
#include "system_wrappers/include/ntp_time.h"
namespace webrtc {
// January 1970, in NTP seconds.
const uint32_t kNtpJan1970 = 2208988800UL;
// Magic NTP fractional unit.
const double kMagicNtpFractionalUnit = 4.294967296E+9;
// A clock interface that allows reading of absolute and relative timestamps.
class Clock {
public:
virtual ~Clock() {}
// Return a timestamp in milliseconds relative to some arbitrary source; the
// source is fixed for this clock.
virtual int64_t TimeInMilliseconds() = 0;
// Return a timestamp in microseconds relative to some arbitrary source; the
// source is fixed for this clock.
virtual int64_t TimeInMicroseconds() = 0;
// Retrieve an NTP absolute timestamp.
virtual NtpTime CurrentNtpTime() = 0;
// Retrieve an NTP absolute timestamp in milliseconds.
virtual int64_t CurrentNtpInMilliseconds() = 0;
// Converts an NTP timestamp to a millisecond timestamp.
static int64_t NtpToMs(uint32_t seconds, uint32_t fractions) {
return NtpTime(seconds, fractions).ToMs();
}
// Returns an instance of the real-time system clock implementation.
static Clock* GetRealTimeClock();
};
class SimulatedClock : public Clock {
public:
explicit SimulatedClock(int64_t initial_time_us);
~SimulatedClock() override;
// Return a timestamp in milliseconds relative to some arbitrary source; the
// source is fixed for this clock.
int64_t TimeInMilliseconds() override;
// Return a timestamp in microseconds relative to some arbitrary source; the
// source is fixed for this clock.
int64_t TimeInMicroseconds() override;
// Retrieve an NTP absolute timestamp.
NtpTime CurrentNtpTime() override;
// Converts an NTP timestamp to a millisecond timestamp.
int64_t CurrentNtpInMilliseconds() override;
// Advance the simulated clock with a given number of milliseconds or
// microseconds.
void AdvanceTimeMilliseconds(int64_t milliseconds);
void AdvanceTimeMicroseconds(int64_t microseconds);
private:
int64_t time_us_;
std::unique_ptr<RWLockWrapper> lock_;
};
} // namespace webrtc
#endif // SYSTEM_WRAPPERS_INCLUDE_CLOCK_H_