A sample of memory pool

#pragma once
#include <list>
using namespace std;

class BufferPool
{
public:
	BufferPool(size_t size, size_t count);
	virtual ~BufferPool(void);
public:
	///allocate memory
	char* Allocate(size_t size);
	///release memory
	void Release(char* buf);
public:
	size_t GetBufferSize() const { return _bufferSize; };
	size_t GetBufferCount() const { return _bufferCount; };
	size_t GetFreeListSize() const { return _freeList.size(); };
	size_t Size() const { return _bufferCount * _bufferSize; };
private:
	bool IsValidAddr(char*);
	size_t CalSize(char* buf);
	char* MyNew(size_t size);
	void MyDelete(char* buf);
private:
	CRITICAL_SECTION _cs;
	size_t _bufferSize;///< the size of one buffer unit
	size_t _bufferCount;///< the count of all buffer units
	char * _firstAddr;///< the started address of memory pool
	char * _lastAddr;///< the ended address of memory pool
	list<char*> _freeList;
};