Full Distribution

src/lockfree.h

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+/**
+ * Tibia GIMUD Server - a free and open-source MMORPG server emulator
+ * Copyright (C) 2017  Alejandro Mujica <alejandrodemujica@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef FS_LOCKFREE_H_8C707AEB7C7235A2FBC5D4EDDF03B008
+#define FS_LOCKFREE_H_8C707AEB7C7235A2FBC5D4EDDF03B008
+
+#if _MSC_FULL_VER >= 190023918 // Workaround for VS2015 Update 2. Boost.Lockfree is a header-only library, so this should be safe to do.
+#define _ENABLE_ATOMIC_ALIGNMENT_FIX
+#endif
+
+#include <boost/lockfree/stack.hpp>
+
+template <typename T, size_t CAPACITY>
+class LockfreePoolingAllocator : public std::allocator<T>
+{
+	public:
+		template <typename U>
+		explicit constexpr LockfreePoolingAllocator(const U&) {}
+		typedef T value_type;
+
+		T* allocate(size_t) const {
+			T* p; // NOTE: p doesn't have to be initialized
+			if (!getFreeList().pop(p)) {
+				//Acquire memory without calling the constructor of T
+				p = static_cast<T*>(operator new (sizeof(T)));
+			}
+			return p;
+		}
+
+		void deallocate(T* p, size_t) const {
+			if (!getFreeList().bounded_push(p)) {
+				//Release memory without calling the destructor of T
+				//(it has already been called at this point)
+				operator delete(p);
+			}
+		}
+
+	private:
+		typedef boost::lockfree::stack<T*, boost::lockfree::capacity<CAPACITY>> FreeList;
+		static FreeList& getFreeList() {
+			static FreeList freeList;
+			return freeList;
+		}
+};
+
+#endif