CYBSemaphore.cpp

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#include "CYB.hpp"

void CYB::Platform::System::Semaphore::SignalAll(void) noexcept {
    Lock();
    FWakeCount += FSleepCount;
    WakeAll();
    Unlock();
}

void CYB::Platform::System::Semaphore::SignalN(const unsigned long long AN) noexcept {
    Lock();
    FWakeCount += AN;
    for (auto I(0ULL); I < AN; ++I)
        WakeOne();
    Unlock();
}

void CYB::Platform::System::Semaphore::Wait(void) noexcept {
    Lock();

    const auto WaitingFor(FServiceCount);
    ++FServiceCount;

    API::Assert::NotEqual(FServiceCount, 0ULL);

    bool NotFirst(false);
    while (FWakeCount < WaitingFor) {
        if (NotFirst)
            WakeOne();

        ++FSleepCount;
        std::atomic_thread_fence(std::memory_order_release);
        EnterCV();
        std::atomic_thread_fence(std::memory_order_acquire);
        --FSleepCount;

        NotFirst = true;
    }

    if (FSleepCount == 0) {
        //take this opportunity to reset the counters
        //overflow will never happen in a million years, but it would be BAD
        FServiceCount = 1;
        FWakeCount = 0;
        std::atomic_thread_fence(std::memory_order_release);
    }

    Unlock();
}