[+] AuFutexBarrier

Include/Aurora/Runtime.hpp

@@ -142,6 +142,7 @@ using AuBinarySemaphore = AuThreadPrimitives::Event;
 using AuFutexMutex = AuThreading::Waitables::FutexWaitable;
 using AuFutexSemaphore = AuThreading::Waitables::FutexSemaphoreWaitable;
 using AuFutexCond = AuThreading::Waitables::FutexCondWaitable;
+using AuFutexBarrier = AuThreading::Waitables::FutexBarrier;
 
 using AuInitOnce = AuThreading::InitOnce;
 using AuInitOnceSmall = __audetail::InitOnceABI;

Include/Aurora/Threading/Waitables/FutexBarrier.hpp

@@ -0,0 +1,126 @@
+/***
+    Copyright (C) 2023 J Reece Wilson (a/k/a "Reece"). All rights reserved.
+
+    File: FutexBarrier.hpp
+    Date: 2023-09-20
+    Author: Reece
+***/
+#pragma once
+
+#include "../WakeOnAddress.hpp"
+#include "../SpinTime.hpp"
+
+namespace Aurora::Threading::Waitables
+{
+    struct FutexBarrier final
+    {
+        inline constexpr FutexBarrier(AuUInt32 uExpectThreads) :
+            uAtomicSleeping(uExpectThreads),
+            uAtomicState(0)
+        {}
+
+        AU_NO_COPY_NO_MOVE(FutexBarrier);
+
+        inline bool Enter()
+        {
+            bool bTimeout {};
+            return this->Park(bTimeout, true, 0);
+        }
+        
+        inline AuPair<bool /* bSuccess */, bool /* bTimeOut */>
+            EnterTimed(AuUInt64 uTimeoutAbsNS)
+        {
+            bool bTimeout {};
+            bool bSuccess = this->Park(bTimeout, true, uTimeoutAbsNS);
+            return AuMakePair(bSuccess, bTimeout);
+        }
+
+        inline bool TryEnter()
+        {
+            return this->TryEnterNoSpin();
+        }
+
+        inline bool TryWait()
+        {
+            return this->TryChkNoSpin();
+        }
+
+        inline bool Wait(AuUInt64 uTimeoutAbsNS = 0)
+        {
+            bool bTimeout {};
+            (void)this->Park(bTimeout, false, uTimeoutAbsNS);
+            return !bTimeout;
+        }
+
+    private:
+        auline bool Park(bool &bTimedOut, bool bTakeOwnership, AuUInt64 uTimeoutAbsNS)
+        {
+            static const AuUInt32 kRef { 0 };
+            
+            bTimedOut = false;
+            
+            if (bTakeOwnership)
+            {
+                if (!this->TryEnterNoSpin())
+                {
+                    return false;
+                }
+            }
+            
+            if (this->TryChkNoSpin())
+            {
+                return true;
+            }
+
+            (void)TryWaitOnAddress((const void *)&this->uAtomicState, &kRef, sizeof(kRef));
+            
+            while (!this->TryChkNoSpin())
+            {
+                if (!WaitOnAddressSteady((const void *)&this->uAtomicState, &kRef, sizeof(kRef), uTimeoutAbsNS))
+                {
+                    if (this->TryChkNoSpin())
+                    {
+                        return true;
+                    }
+                    else
+                    {
+                        bTimedOut = true;
+                        return false;
+                    }
+                }
+            }
+            
+            return true;
+        }
+        
+        auline bool TryEnterNoSpin()
+        {
+            AuUInt32 uState;
+                
+            while ((uState = AuAtomicLoad(&this->uAtomicSleeping)) != 0)
+            {
+                if (AuAtomicCompareExchange(&this->uAtomicSleeping, uState - 1, uState) == uState)
+                {
+                    if (uState == 1)
+                    {
+                        AuAtomicStore(&this->uAtomicState, 1u);
+                        WakeAllOnAddress((const void *)&this->uAtomicState);
+                    }
+                    
+                    return true;
+                }
+            }
+            
+            return false;
+        }
+
+        auline bool TryChkNoSpin()
+        {
+            return AuAtomicLoad(&this->uAtomicState) == 1;
+        }
+
+    public:
+        AuAUInt32 uAtomicState {};
+        AuAUInt32 uAtomicSleeping {};
+    };
+}

Include/Aurora/Threading/Waitables/Waitables.hpp

@@ -12,3 +12,4 @@
 #include "FutexWaitable.hpp"
 #include "FutexSemaphoreWaitable.hpp"
 #include "FutexCondWaitable.hpp"
+#include "FutexBarrier.hpp"