Compute Library
 21.05
Semaphore.h
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1 /*
2  * Copyright (c) 2017-2018 Arm Limited.
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24 #ifndef __ARM_COMPUTE_UTILS_SEMAMPHORE_H__
25 #define __ARM_COMPUTE_UTILS_SEMAMPHORE_H__
26 
27 #include "Mutex.h"
28 #include "support/Mutex.h"
29 #include <condition_variable>
30 
31 namespace arm_compute
32 {
33 #ifndef NO_MULTI_THREADING
34 /** Semamphore class */
35 class Semaphore
36 {
37 public:
38  /** Default Constuctor
39  *
40  * @param[in] value Semaphore initial value
41  */
42  Semaphore(int value = 0)
43  : _value(value), _m(), _cv()
44  {
45  }
46  /** Signals a semaphore */
47  inline void signal()
48  {
49  {
50  std::lock_guard<std::mutex> lock(_m);
51  ++_value;
52  }
53  _cv.notify_one();
54  }
55  /** Waits on a semaphore */
56  inline void wait()
57  {
58  std::unique_lock<std::mutex> lock(_m);
59  _cv.wait(lock, [this]()
60  {
61  return _value > 0;
62  });
63  --_value;
64  }
65 
66 private:
67  int _value;
69  std::condition_variable _cv;
70 };
71 #else /* NO_MULTI_THREADING */
72 /** Empty semamphore class */
73 class Semaphore
74 {
75 public:
76  Semaphore(int value = 0)
77  : _value(value)
78  {
79  (void)_value;
80  }
81  /** Signals a semaphore */
82  inline void signal()
83  {
84  (void)_value;
85  }
86  /** Waits on a semaphore */
87  inline void wait()
88  {
89  (void)_value;
90  }
91 
92 private:
93  int _value;
94 };
95 #endif /* NO_MULTI_THREADING */
96 } // arm_compute
97 #endif /* __ARM_COMPUTE_UTILS_SEMAMPHORE_H__ */
Semamphore class.
Definition: Semaphore.h:35
void wait()
Waits on a semaphore.
Definition: Semaphore.h:56
Semaphore(int value=0)
Default Constuctor.
Definition: Semaphore.h:42
std::mutex Mutex
Wrapper of Mutex data-object.
Definition: Mutex.h:33
Copyright (c) 2017-2021 Arm Limited.
void signal()
Signals a semaphore.
Definition: Semaphore.h:47