Half Life Game Level Viewer

//
//	PoolAllocator.h
//
//	Simple pool allocation template class derived from Allocator template class.  This class will provide a pointer to 
//	a single block of type T from the pool.  If the requested number of blocks is greater than one then the 
//	block array will be allocated using 'new' instead of from the pool.
//
//	Copyright 2005 Paul Higinbotham
//

#ifndef __POOLALLOCATOR_H_
#define __POOLALLOCATOR_H_


#include "allocator.h"
#include "..\sorting\HeapSort.h"
#include <new>							// This may cause the std C++ "throwing" new operator to be used
#include <cassert>


namespace ZGraphics
{


#define DEFAULT_POOL_SIZE	50


template <typename T>
class PoolAllocator : public Allocator<T>
{
public:
	PoolAllocator();
	PoolAllocator(size_t tSize);
	virtual ~PoolAllocator();

	virtual T * Allocate(size_t tNumBlocks);
	virtual void Deallocate(T * pBlock, size_t tNumBlocks);

	// Used to create new pool allocator for a different type
	template <typename U>
	struct rebind { typedef PoolAllocator<U> other; };

	// Accessors
	size_t GetPoolSize() const { return m_tSize; };
	size_t GetFreeBlocks() const { return m_tSize - m_tCurrent; }
	size_t GetPoolOverflow() const { return m_tPoolOverflow; }
	size_t GetNewAllocations() const { return m_tNewAllocate; }
	bool GetDestroyAllocatedBlocks() const { return m_bDestroyAllocatedBlocks; }
	void SetDestroyAllocatedBlocks(bool bDoit) { m_bDestroyAllocatedBlocks = bDoit; }

protected:
	void _createPool(size_t tSize);
	inline bool _isFromThisPool(T * pBlock);

private:
	inline void _initMembers();
	void _destroyAllocatedBlocks();
	bool _isPtrInList(T** ppBlocks, size_t tSize, T* pPtr);

private:
	unsigned char *	m_pPool;			// Pointer to allocated memory for blocks of T
	T *				m_pPoolLast;
	T **			m_ppBlocks;			// Pointer to T blocks in allocated memory pool
	size_t			m_tSize;			// Number of T blocks in m_pPool allocation
	size_t			m_tCurrent;			// Current free block pointer
	bool			m_bDestroyAllocatedBlocks;

	size_t			m_tPoolOverflow;	// Count of times pool was full during an allocation request
	size_t			m_tNewAllocate;		// Count of times new was used to allocate instead of pool
};


// Include inline implementation file
#include "PoolAllocator.inl"


} /* namespace ZGraphics */


#endif	/* __POOLALLOCATOR_H_ */