- initial import

src/engine/helper/HL_Singletone.h

@@ -0,0 +1,38 @@
+#ifndef __HL_SINGLETONE_H
+#define __HL_SINGLETONE_H
+
+#include <atomic>
+#include <mutex>
+
+template <class T>
+class SafeSingleton
+{
+protected:
+  static std::atomic<T*> SharedInstance;
+  static std::mutex mMutex;
+public:
+  static T& instance()
+  {
+    T* tmp = SharedInstance.load(std::memory_order_relaxed);
+    std::atomic_thread_fence(std::memory_order_acquire);
+    if (tmp == nullptr)
+    {
+        std::lock_guard<std::mutex> lock(mMutex);
+        tmp = SharedInstance.load(std::memory_order_relaxed);
+        if (tmp == nullptr)
+        {
+            tmp = new T();
+            std::atomic_thread_fence(std::memory_order_release);
+            SharedInstance.store(tmp, std::memory_order_relaxed);
+        }
+    }
+    return *tmp;
+  }
+};
+
+template <class T>
+std::atomic<T*> SafeSingleton<T>::SharedInstance;
+template <class T>
+std::mutex SafeSingleton<T>::mMutex;
+
+#endif