Roc Toolkit internal modules
Roc Toolkit: real-time audio streaming
ticker.h
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1 /*
2  * Copyright (c) 2017 Roc authors
3  *
4  * This Source Code Form is subject to the terms of the Mozilla Public
5  * License, v. 2.0. If a copy of the MPL was not distributed with this
6  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
7  */
8 
9 //! @file roc_core/ticker.h
10 //! @brief Ticker.
11 
12 #ifndef ROC_CORE_TICKER_H_
13 #define ROC_CORE_TICKER_H_
14 
15 #include "roc_core/noncopyable.h"
16 #include "roc_core/panic.h"
17 #include "roc_core/time.h"
18 
19 namespace roc {
20 namespace core {
21 
22 //! Ticker.
23 class Ticker : public NonCopyable<> {
24 public:
25  //! Number of ticks.
26  typedef uint64_t Ticks;
27 
28  //! Initialize.
29  //! @remarks
30  //! @p freq defines the number of ticks per second.
31  explicit Ticker(Ticks freq)
32  : ratio_(double(freq) / Second)
33  , start_(0)
34  , started_(false) {
35  }
36 
37  //! Start ticker.
38  void start() {
39  if (started_) {
40  roc_panic("ticker: can't start ticker twice");
41  }
42  start_ = timestamp();
43  started_ = true;
44  }
45 
46  //! Returns number of ticks elapsed since start.
47  //! If ticker is not started yet, it is started automatically.
48  Ticks elapsed() {
49  if (!started_) {
50  start();
51  return 0;
52  } else {
53  return Ticks(double(timestamp() - start_) * ratio_);
54  }
55  }
56 
57  //! Wait until the given number of ticks elapses since start.
58  //! If ticker is not started yet, it is started automatically.
59  void wait(Ticks ticks) {
60  if (!started_) {
61  start();
62  }
63  sleep_until(start_ + nanoseconds_t(ticks / ratio_));
64  }
65 
66 private:
67  const double ratio_;
68  nanoseconds_t start_;
69  bool started_;
70 };
71 
72 } // namespace core
73 } // namespace roc
74 
75 #endif // ROC_CORE_TICKER_H_
uint64_t Ticks
Number of ticks.
Definition: ticker.h:26
Time definitions.
Ticker(Ticks freq)
Initialize.
Definition: ticker.h:31
Root namespace.
int64_t nanoseconds_t
Nanoseconds.
Definition: time.h:21
void wait(Ticks ticks)
Wait until the given number of ticks elapses since start. If ticker is not started yet...
Definition: ticker.h:59
void sleep_until(nanoseconds_t timestamp)
Sleep until the specified absolute time point has been reached.
#define roc_panic(...)
Print error message and terminate program gracefully.
Definition: panic.h:42
Base class for non-copyable objects.
Definition: noncopyable.h:23
Ticks elapsed()
Returns number of ticks elapsed since start. If ticker is not started yet, it is started automaticall...
Definition: ticker.h:48
Panic function.
const nanoseconds_t Second
One second represented in nanoseconds.
Definition: time.h:33
void start()
Start ticker.
Definition: ticker.h:38
Non-copyable object.
nanoseconds_t timestamp()
Get current timestamp in nanoseconds.
Ticker.
Definition: ticker.h:23