Core/MemoryPool: Add iterator

include/Nazara/Core/MemoryPool.hpp

@@ -9,6 +9,7 @@
 
 #include <Nazara/Prerequisites.hpp>
 #include <Nazara/Core/Bitset.hpp>
+#include <iterator>
 #include <memory>
 #include <vector>
 
@@ -18,6 +19,9 @@ namespace Nz
 	class MemoryPool
 	{
 		public:
+			class iterator;
+			friend iterator;
+
 			MemoryPool(std::size_t blockSize);
 			MemoryPool(const MemoryPool&) = delete;
 			MemoryPool(MemoryPool&&) noexcept = default;
@@ -36,8 +40,14 @@ namespace Nz
 
 			void Reset();
 
+			T* RetrieveFromIndex(std::size_t index);
 			std::size_t RetrieveEntryIndex(const T* data);
 
+			// std interface
+			iterator begin();
+			iterator end();
+			std::size_t size();
+
 			MemoryPool& operator=(const MemoryPool&) = delete;
 			MemoryPool& operator=(MemoryPool&& pool) noexcept = default;
 
@@ -45,6 +55,10 @@ namespace Nz
 
 		private:
 			void AllocateBlock();
+			T* GetAllocatedPointer(std::size_t blockIndex, std::size_t localIndex);
+			std::pair<std::size_t, std::size_t> GetFirstAllocatedEntry() const;
+			std::pair<std::size_t, std::size_t> GetFirstAllocatedEntryFromBlock(std::size_t blockIndex) const;
+			std::pair<std::size_t, std::size_t> GetNextAllocatedEntry(std::size_t blockIndex, std::size_t localIndex) const;
 
 			using AlignedStorage = std::aligned_storage_t<sizeof(T), Alignment>;
 
@@ -53,11 +67,45 @@ namespace Nz
 				std::size_t occupiedEntryCount = 0;
 				std::unique_ptr<AlignedStorage[]> memory;
 				Bitset<UInt64> freeEntries;
+				Bitset<UInt64> occupiedEntries; //< Opposite of freeEntries
 			};
 
 			std::size_t m_blockSize;
 			std::vector<Block> m_blocks;
 	};
+
+	template<typename T, std::size_t Alignment>
+	class MemoryPool<T, Alignment>::iterator
+	{
+		friend MemoryPool;
+
+		public:
+			using iterator_category = std::input_iterator_tag;
+			using value_type = T;
+			using difference_type = std::ptrdiff_t;
+			using pointer = T*;
+			using reference = T&;
+
+			iterator(const iterator&) = default;
+			iterator(iterator&&) = default;
+
+			iterator& operator=(const iterator&) = default;
+			iterator& operator=(iterator&&) = default;
+
+			iterator operator++(int);
+			iterator& operator++();
+
+			bool operator==(const iterator& rhs) const;
+			bool operator!=(const iterator& rhs) const;
+			reference operator*() const;
+
+		private:
+			iterator(MemoryPool* owner, std::size_t blockIndex, std::size_t localIndex);
+
+			std::size_t m_blockIndex;
+			std::size_t m_localIndex;
+			MemoryPool* m_owner;
+	};
 }
 
 #include <Nazara/Core/MemoryPool.inl>