内存映射

内存映射：

HANDLE CreateFileMapping(Handle 文件，PSECURITY_ATTRIBUTES 安全属性，DWORD 保护属性，DWORD 文件大小高32位，DWORD 文件大小低32位，PCTSTR 映射名称)

PVOID MAPViewOfFile(HANDLE 映射对象，DWORD访问属性，DWORD 偏移量高32位，DWORD 偏移量低32位，SIZE_T 字节数)

//调用的时候传入地址就可以，测试用的txt文件

void Mapping(LPCTSTR path) {
     HANDLE fFile01 = (HANDLE) CreateFile(path, GENERIC_WRITE | GENERIC_READ, 0, NULL,CREATE_NEW, FILE_ATTRIBUTE_NORMAL, NULL);
    char chBuffer[256];
    memcpy(chBuffer, "testing", 7);
    DWORD dwWritenSize = 0;
    BOOL bRet = WriteFile(hFile01, chBuffer, 7, &dwWritenSize, NULL);
    CloseHandle(hFile01);
    HANDLE hFile = CreateFile(path, GENERIC_WRITE | GENERIC_READ, 0, NULL,OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
    DWORD dwFileSize = GetFileSize(hFile, NULL);
    //创建一个内存映射文件，大小为打开文件大小
    HANDLE hFileMap = CreateFileMapping(hFile, NULL, PAGE_READWRITE, 0,dwFileSize , NULL);
    //预定一块地址空间区域，并可以通过指针访问
    PVOID pvFile = MapViewOfFile(hFileMap, FILE_MAP_WRITE, 0, 0, 0);
    PSTR pch = (PSTR)pvFile;
    //小写变大写
    strupr(pch);
    cout << pch << endl;
    //从进程空间撤销对文件数据的关联
    UnmapViewOfFile(pvFile);
    CloseHandle(hFileMap);
    SetFilePointer(hFile, dwFileSize, NULL, FILE_BEGIN);
    SetEndOfFile(hFile);
    CloseHandle(hFile);
}