From c27187ae4b83034796a55d8d223589c2c5adcf58 Mon Sep 17 00:00:00 2001
From: Lynix <lynix680@gmail.com>
Date: Wed, 28 May 2014 10:02:43 +0200
Subject: [PATCH] Added MemoryPool class

Former-commit-id: cc704583a686dd631bee54ed48cee913aeb2e369
---
 include/Nazara/Core/MemoryPool.hpp | 36 +++++++++++++
 include/Nazara/Core/MemoryPool.inl | 87 ++++++++++++++++++++++++++++++
 2 files changed, 123 insertions(+)
 create mode 100644 include/Nazara/Core/MemoryPool.hpp
 create mode 100644 include/Nazara/Core/MemoryPool.inl

diff --git a/include/Nazara/Core/MemoryPool.hpp b/include/Nazara/Core/MemoryPool.hpp
new file mode 100644
index 000000000..0e9fb32e9
--- /dev/null
+++ b/include/Nazara/Core/MemoryPool.hpp
@@ -0,0 +1,36 @@
+// Copyright (C) 2014 Jérôme Leclercq
+// This file is part of the "Nazara Engine - Graphics module"
+// For conditions of distribution and use, see copyright notice in Config.hpp
+
+#pragma once
+
+#ifndef NAZARA_MEMORYPOOL_HPP
+#define NAZARA_MEMORYPOOL_HPP
+
+#include <Nazara/Prerequesites.hpp>
+#include <memory>
+
+template<unsigned int typeSize, unsigned int count = 1000, bool canGrow = true>
+class NzMemoryPool
+{
+	public:
+		NzMemoryPool();
+		~NzMemoryPool() = default;
+
+		template<typename T> T* Allocate();
+		void* Allocate(unsigned int size);
+		void Free(void* ptr);
+
+	private:
+		NzMemoryPool(NzMemoryPool* pool);
+
+		std::unique_ptr<void*[]> m_freeList;
+		std::unique_ptr<nzUInt8[]> m_pool;
+		std::unique_ptr<NzMemoryPool> m_next;
+		NzMemoryPool* m_previous;
+		unsigned int m_freeCount;
+};
+
+#include <Nazara/Core/MemoryPool.inl>
+
+#endif // NAZARA_MEMORYPOOL_HPP
diff --git a/include/Nazara/Core/MemoryPool.inl b/include/Nazara/Core/MemoryPool.inl
new file mode 100644
index 000000000..21c07a828
--- /dev/null
+++ b/include/Nazara/Core/MemoryPool.inl
@@ -0,0 +1,87 @@
+// Copyright (C) 2014 Jérôme Leclercq
+// This file is part of the "Nazara Engine - Core module"
+// For conditions of distribution and use, see copyright notice in Config.hpp
+
+#include <new>
+#include <Nazara/Core/Debug.hpp>
+
+template<unsigned int typeSize, unsigned int count, bool canGrow>
+NzMemoryPool<typeSize, count, canGrow>::NzMemoryPool() :
+m_previous(nullptr),
+m_freeCount(count)
+{
+	m_pool.reset(new nzUInt8[typeSize * count]);
+	m_freeList.reset(new void*[count]);
+
+	// Remplissage de la free list
+	for (unsigned int i = 0; i < count; ++i)
+		m_freeList[i] = &m_pool[typeSize * (count-i-1)];
+}
+
+template<unsigned int typeSize, unsigned int count, bool canGrow>
+NzMemoryPool<typeSize, count, canGrow>::NzMemoryPool(NzMemoryPool* pool) :
+NzMemoryPool()
+{
+	m_previous = pool;
+}
+
+template<unsigned int typeSize, unsigned int count, bool canGrow>
+template<typename T>
+T* NzMemoryPool<typeSize, count, canGrow>::Allocate()
+{
+	static_assert(sizeof(T) <= typeSize, "This type is too large for this memory pool");
+
+	return static_cast<T*>(Allocate(sizeof(T)));
+}
+
+template<unsigned int typeSize, unsigned int count, bool canGrow>
+void* NzMemoryPool<typeSize, count, canGrow>::Allocate(unsigned int size)
+{
+	if (size > typeSize)
+	{
+		throw std::bad_alloc();
+		return nullptr;
+	}
+
+	if (m_freeCount > 0)
+		return m_freeList[--m_freeCount];
+	else if (canGrow)
+	{
+		if (!m_next)
+			m_next.reset(new NzMemoryPool(this));
+
+		return m_next->Allocate(size);
+	}
+
+	throw std::bad_alloc();
+	return nullptr;
+}
+
+template<unsigned int typeSize, unsigned int count, bool canGrow>
+void NzMemoryPool<typeSize, count, canGrow>::Free(void* ptr)
+{
+	if (ptr)
+	{
+		// Le pointer nous appartient-il ?
+		if (ptr >= m_pool.get() && ptr < m_pool.get() + typeSize*count)
+		{
+			m_freeList[m_freeCount++] = ptr;
+
+			// Si nous somme vide et l'extension d'un autre pool, on se suicide
+			if (m_freeCount == count && m_previous && !m_next)
+			{
+				m_previous->m_next.release();
+				delete this; // Suicide
+			}
+		}
+		else
+		{
+			if (m_next)
+				m_next->Free(ptr);
+			else
+				throw std::runtime_error("Pointer does not belong to memory pool");
+		}
+	}
+}
+
+#include <Nazara/Core/DebugOff.hpp>