2010/7/26 共享内存封装

本文介绍一个共享内存封装类，使共享内存的使用更简单化，特别适合更懒的程序员使用:-)

一、实现目标：简单化使用共享内存

二、使用说明：

1. 创建共享内存CSFMServer对象, 需要为CSFMServer对象指定专用的名字，只要
系统中存在一个这样的对象，就可以在其他程序中简单方便地使用该共享内存。

CSFMServer(char *szFileName, char *szMapName, DWORD dwSize); Create(char *szFileName, char *szMapName, DWORD dwSize); 

参数1:NULL或指定的文件(将创建或打开并读写/麻烦)
参数2:要创建的共享内存对象名
参数3:要创建的共享内存对象大小

例如

m_SFMS.Create(NULL, "_ZZZ_OBJ_", 1);

2. 本地使用共享内存
使用 LPVOID GetBuffer() 返回共享内存地址,例如

char *p = (char*)m_SFMS.GetBuffer();if (p) strcpy(p, "1234567890");

3. 创建共享内存CSFMClient对象，也需要为CSFMClient对象指定专用的名字（上一步使用的那个），即可使用共享内存。

CSFMClient(DWORD dwAccess, char *szMapName);Open(DWORD dwAccess, char *szMapName);

参数1:共享内存对象访问方式(FILE_MAP_READ|FILE_MAP_WRITE)
参数2:共享内存对象名

例如:

CSFMClient *pCSFMC = new CSFMClient(FILE_MAP_READ, "_OBJ_ZZZ_");

4. 本地使用共享内存
使用 LPVOID GetBuffer() 返回共享内存地址，例如

char *p = (char*)pCSFMC->GetBuffer();if (p) strcpy(p, "1234567890");

三、该类的具体实现代码如下:

//------------------------------------------------
// 2002/07/05
// awzzz
// SFMMem.h: interface for the CSFMServer class.
//------------------------------------------------

#if !defined(AFX_SFMSERVER_H__2D76A439_6388_4B07_AE7A_C82F458642ED__INCLUDED_)#define AFX_SFMSERVER_H__2D76A439_6388_4B07_AE7A_C82F458642ED__INCLUDED_#if _MSC_VER > 1000#pragma once#endif // _MSC_VER > 1000#define DEFAULT_FILENAME NULL#define DEFAULT_MAPNAME  "_SFM_OBJ_"#define DEFAULT_MAPSIZE  (0xFFFF + 1)

// Shared FileMap Server

class CSFMServer  {public: CSFMServer(); virtual ~CSFMServer(); CSFMServer(char *szFileName, char *szMapName, DWORD dwSize);protected: HANDLE m_hFile; HANDLE m_hFileMap; LPVOID m_lpFileMapBuffer; char *m_pFileName; char *m_pMapName; DWORD m_dwSize; int  m_iCreateFlag;private: void _Init(); void _Destory();public: void Create(char *szFileName, char *szMapName, DWORD dwSize); LPVOID GetBuffer(); DWORD GetSize();};

// Shared FileMap Client

class CSFMClient  {public: CSFMClient(); virtual ~CSFMClient(); CSFMClient(DWORD dwAccess, char *szMapName);protected: HANDLE m_hFileMap; LPVOID m_lpFileMapBuffer; char *m_pMapName; int  m_iOpenFlag;private: void _Init(); void _Destory();public: void Open(DWORD dwAccess, char *szMapName); LPVOID GetBuffer(); DWORD GetSize();};#endif // !defined(AFX_SFMSERVER_H__2D76A439_6388_4B07_AE7A_C82F458642ED__INCLUDED_)

//------------------------------------------------------
// SFMMem.cpp: implementation of the CSFMServer class.
//------------------------------------------------------

#include "stdafx.h"#include "SFMMem.h"#ifdef _DEBUG#undef THIS_FILEstatic char THIS_FILE[]=__FILE__;#define new DEBUG_NEW#endif// Construction/DestructionCSFMServer::CSFMServer(){ _Init(); // Create(DEFAULT_FILENAME, DEFAULT_MAPNAME, DEFAULT_MAPSIZE);}CSFMServer::~CSFMServer(){ _Destory();}CSFMServer::CSFMServer(char *szFileName, char *szMapName, DWORD dwSize){ _Init(); // Create(szFileName, szMapName, dwSize);}void CSFMServer::_Init(){ m_hFile = NULL; m_hFileMap = NULL; m_lpFileMapBuffer = NULL; m_pFileName = NULL; m_pMapName = NULL; m_dwSize = 0; m_iCreateFlag = 0;}void CSFMServer::_Destory(){ if (m_lpFileMapBuffer) {  UnmapViewOfFile(m_lpFileMapBuffer);  m_lpFileMapBuffer = NULL; }  if (m_hFileMap) {  CloseHandle(m_hFileMap);  m_hFileMap = NULL; }  if (m_hFile && m_hFile != INVALID_HANDLE_VALUE) {  CloseHandle(m_hFile);  m_hFile = NULL; } if (m_pFileName) {  free(m_pFileName);  m_pFileName = NULL; } if (m_pMapName) {  free(m_pMapName);  m_pMapName = NULL; } _Init();}void CSFMServer::Create(char *szFileName, char *szMapName, DWORD dwSize){ if (m_iCreateFlag)  _Destory(); if (szFileName)  m_pFileName = _strdup(szFileName); //else m_pFileName = NULL; if (szMapName)  m_pMapName = _strdup(szMapName); else m_pMapName = _strdup(DEFAULT_MAPNAME); if (dwSize > 0)  m_dwSize = dwSize; else m_dwSize = DEFAULT_MAPSIZE; if (m_pFileName) {  // file  m_hFile = CreateFile(   m_pFileName,   GENERIC_READ|GENERIC_WRITE,   FILE_SHARE_READ|FILE_SHARE_WRITE,   NULL,   OPEN_ALWAYS,//OPEN_EXISTING,   FILE_ATTRIBUTE_NORMAL,   NULL   ); } else {  // system  m_hFile = (HANDLE)0xFFFFFFFF; } if (m_hFile) {  m_hFileMap = CreateFileMapping(   m_hFile,   NULL,   PAGE_READWRITE,   0,   m_dwSize,   m_pMapName   );  //使只有一个CSFMServer对象能操作内存对象  //if (m_hFileMap != NULL && ERROR_ALREADY_EXISTS == GetLastError())  //{  // CloseHandle(m_hFileMap);  // m_hFileMap = NULL;  //} } if (m_hFileMap) {  m_lpFileMapBuffer = MapViewOfFile(   m_hFileMap,   FILE_MAP_ALL_ACCESS,//FILE_MAP_WRITE|FILE_MAP_READ,   0,   0,   m_dwSize   ); } m_iCreateFlag = 1;}LPVOID CSFMServer::GetBuffer(){ return (m_lpFileMapBuffer)?(m_lpFileMapBuffer):(NULL);}DWORD CSFMServer::GetSize(){ return m_dwSize;}// Construction/DestructionCSFMClient::CSFMClient(){ _Init(); // Open(FILE_MAP_READ, DEFAULT_MAPNAME);}CSFMClient::~CSFMClient(){ _Destory();}CSFMClient::CSFMClient(DWORD dwAccess, char *szMapName){ _Init(); // Open(dwAccess, szMapName);}void CSFMClient::Open(DWORD dwAccess, char *szMapName){ if (m_iOpenFlag)  _Destory(); if (szMapName)  m_pMapName = _strdup(szMapName); else m_pMapName = _strdup(DEFAULT_MAPNAME); m_hFileMap = OpenFileMapping(  dwAccess,  TRUE,  m_pMapName  ); if (m_hFileMap) {  m_lpFileMapBuffer = MapViewOfFile(   m_hFileMap,   dwAccess,   0,   0,   0   ); } m_iOpenFlag = 1;}void CSFMClient::_Init(){ m_hFileMap = NULL; m_lpFileMapBuffer = NULL; m_pMapName = NULL; m_iOpenFlag = 0;}void CSFMClient::_Destory(){ if (m_lpFileMapBuffer) {  UnmapViewOfFile(m_lpFileMapBuffer);  m_lpFileMapBuffer = NULL; }  if (m_hFileMap) {  CloseHandle(m_hFileMap);  m_hFileMap = NULL; } if (m_pMapName) {  free(m_pMapName);  m_pMapName = NULL; } _Init();}LPVOID CSFMClient::GetBuffer(){ return (m_lpFileMapBuffer)?(m_lpFileMapBuffer):(NULL);}DWORD CSFMClient::GetSize(){ // unnable use return 0;}