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文件共享内存C++类头文件

文件共享内存类是指把文件按共享内存方式打开使用，有更新时刷新到内存和硬件文件上，这样避免一直打开文件，相当于把文件缓冲到内存里，在读取写入文件数据时，效率高。下面是文件共享内存C++类头文件的代码，实用代码，注意收藏：

class CMapStringToPtr;
class CKingKlineMemFile 
{
//	DECLARE_DYNCREATE(CKingKlineMemFile)


// Attributes
public:
	CKingKlineMemFile();           // protected constructor used by dynamic creation

// Operations
public:
// Flag values
	CMapStringToPtr* m_pSymbolToPos;
	enum OpenFlags {
		modeRead =          0x0000,
		modeWrite =         0x0001,
		modeReadWrite =     0x0002,
		shareCompat =       0x0000,
		shareExclusive =    0x0010,
		shareDenyWrite =    0x0020,
		shareDenyRead =     0x0030,
		shareDenyNone =     0x0040,
		modeNoInherit =     0x0080,
		modeCreate =        0x1000,
		modeNoTruncate =    0x2000,
		typeText =          0x4000, // typeText and typeBinary are used in
		typeBinary =   (int)0x8000 // derived classes only
		};

	enum Attribute {
		normal =    0x00,
		readOnly =  0x01,
		hidden =    0x02,
		system =    0x04,
		volume =    0x08,
		directory = 0x10,
		archive =   0x20
		};

	enum SeekPosition { begin = 0x0, current = 0x1, end = 0x2 };

	enum { hFileNull = -1 };

// Constructors
	CKingKlineMemFile(LPCTSTR lpszFileName, UINT nOpenFlags);


// Operations
	void SetSmallBlockCount(int nBlock);//set the total count of small block
	int GetSmallBlockCount();//get the total count of small block
	void SetStockNumber(int nStock);//set the total count of stock
	int GetStockNumber();//get the total count of stock

	virtual BOOL Open(LPCTSTR lpszFileName, UINT nOpenFlags, int nAddToFileEnd =0 ,CFileException* pException = NULL);
	virtual BOOL OpenShare(LPCTSTR lpszFileName, UINT nOpenFlags, int nAddToFileEnd =0 ,CString sShareName = "",CFileException* pException = NULL);

	DWORD SeekToEnd();
	void SeekToBegin();

// Overridables

	LONG Seek(LONG lOff, UINT nFrom);
	virtual DWORD GetLength() const;

	virtual UINT Read(void* lpBuf, int nCount);
	virtual void Write(const void* lpBuf, UINT nCount);

//	virtual void LockRange(DWORD dwPos, DWORD dwCount);
//	virtual void UnlockRange(DWORD dwPos, DWORD dwCount);

//	virtual void Abort();
	virtual void Flush();
	virtual void Close();

// Implementation
public:
	CString GetFileName(){return m_strFileName;}
protected:
	void SetMaxNumStock(WORD nMaxNumStock);
	WORD GetMaxNumStock();
	int MaxNumStock;
	BOOL m_bCloseOnDelete;
	CString m_strFileName;
	int m_nAddReMap;

// Attributes
	UINT m_hFile;
	HANDLE m_hFileMap;
	BYTE* m_lpvFileBegin;////the pointer of the begin of file 
	BYTE* m_lpvFileEnd;//the pointer of the end of file 
	BYTE* m_lpvFileCurrent;//the pointer of the current of file 
	DWORD	m_nLenFile;

// Overrides
	// ClassWizard generated virtual function overrides
	//{{AFX_VIRTUAL(CKingKlineMemFile)
	//}}AFX_VIRTUAL

// Implementation
public:
	int GetID();
	void ReMapFromBegin(int nCount);
	BYTE* GetFileCurrentPointer();
	BYTE * GetFileBeginPointer();
	virtual ~CKingKlineMemFile();
	bool m_bShareMem;
	CString m_sNameShareMem;

private:
	bool ReMap(int nAdd = 1024);
};