61 lines
1.4 KiB
C
61 lines
1.4 KiB
C
|
/**
|
||
|
|
* PANDA 3D SOFTWARE
|
||
|
|
* Copyright (c) Carnegie Mellon University. All rights reserved.
|
||
|
|
*
|
||
|
|
* All use of this software is subject to the terms of the revised BSD
|
||
|
|
* license. You should have received a copy of this license along
|
||
|
|
* with this source code in a file named "LICENSE."
|
||
|
|
*
|
||
|
|
* @file psemaphore.h
|
||
|
|
* @author drose
|
||
|
|
* @date 2008-10-13
|
||
|
|
*/
|
||
|
|
|
||
|
|
#ifndef PSEMAPHORE_H
|
||
|
|
#define PSEMAPHORE_H
|
||
|
|
|
||
|
|
#include "pandabase.h"
|
||
|
|
#include "pmutex.h"
|
||
|
|
#include "conditionVar.h"
|
||
|
|
#include "mutexHolder.h"
|
||
|
|
|
||
|
|
/**
|
||
|
|
* A classic semaphore synchronization primitive.
|
||
|
|
*
|
||
|
|
* A semaphore manages an internal counter which is decremented by each
|
||
|
|
* acquire() call and incremented by each release() call. The counter can
|
||
|
|
* never go below zero; when acquire() finds that it is zero, it blocks,
|
||
|
|
* waiting until some other thread calls release().
|
||
|
|
*/
|
||
|
|
class EXPCL_PANDA_PIPELINE Semaphore {
|
||
|
|
PUBLISHED:
|
||
|
|
INLINE explicit Semaphore(int initial_count = 1);
|
||
|
|
Semaphore(const Semaphore ©) = delete;
|
||
|
|
~Semaphore() = default;
|
||
|
|
|
||
|
|
Semaphore &operator = (const Semaphore ©) = delete;
|
||
|
|
|
||
|
|
PUBLISHED:
|
||
|
|
BLOCKING INLINE void acquire();
|
||
|
|
BLOCKING INLINE bool try_acquire();
|
||
|
|
INLINE int release();
|
||
|
|
|
||
|
|
INLINE int get_count() const;
|
||
|
|
void output(std::ostream &out) const;
|
||
|
|
|
||
|
|
private:
|
||
|
|
Mutex _lock;
|
||
|
|
ConditionVar _cvar;
|
||
|
|
int _count;
|
||
|
|
};
|
||
|
|
|
||
|
|
INLINE std::ostream &
|
||
|
|
operator << (std::ostream &out, const Semaphore &sem) {
|
||
|
|
sem.output(out);
|
||
|
|
return out;
|
||
|
|
}
|
||
|
|
|
||
|
|
#include "psemaphore.I"
|
||
|
|
|
||
|
|
#endif
|