1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950 |
- #pragma once
- #include "CappedSemaphore.h"
- namespace baselib
- {
- BASELIB_CPP_INTERFACE
- {
- // In computer science, a semaphore is a variable or abstract data type used to control access to a common resource by multiple processes in a concurrent
- // system such as a multitasking operating system. A semaphore is simply a variable. This variable is used to solve critical section problems and to achieve
- // process synchronization in the multi processing environment. A trivial semaphore is a plain variable that is changed (for example, incremented or
- // decremented, or toggled) depending on programmer-defined conditions.
- //
- // A useful way to think of a semaphore as used in the real-world system is as a record of how many units of a particular resource are available, coupled with
- // operations to adjust that record safely (i.e. to avoid race conditions) as units are required or become free, and, if necessary, wait until a unit of the
- // resource becomes available.
- //
- // "Semaphore (programming)", Wikipedia: The Free Encyclopedia
- // https://en.wikipedia.org/w/index.php?title=Semaphore_(programming)&oldid=872408126
- //
- // For optimal performance, baselib::BinarySemaphore should be stored at a cache aligned memory location.
- class BinarySemaphore : private CappedSemaphore
- {
- public:
- // Creates a binary semaphore synchronization primitive.
- // Binary means the semaphore can at any given time have at most one token available for consummation.
- //
- // This is just an API facade for CappedSemaphore(1)
- //
- // If there are not enough system resources to create a semaphore, process abort is triggered.
- BinarySemaphore() : CappedSemaphore(1) {}
- using CappedSemaphore::Acquire;
- using CappedSemaphore::TryAcquire;
- using CappedSemaphore::TryTimedAcquire;
- // Submit token to the semaphore.
- // If threads are waiting the token is consumed before this function return.
- //
- // When successful this function is guaranteed to emit a release barrier.
- //
- // \returns true if a token was submitted, false otherwise (meaning the BinarySemaphore already has a token)
- inline bool Release()
- {
- return CappedSemaphore::Release(1) == 1;
- }
- };
- }
- }
|