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C-/C++-Quelltext

// ParseALargeFile - parses a large file and uses a

// progress bar to indicate the progress of the

// parsing operation. 

// Returns TRUE if successful, or FALSE otherwise. 

// hwndParent - parent window of the progress bar. 

// lpszFileName - name of the file to parse. 

// 

// Global variable 

//     g_hinst - instance handle 


extern HINSTANCE g_hinst; 

BOOL ParseALargeFile(HWND hwndParent, LPSTR lpszFileName) 
{ 
    RECT rcClient;  // Client area of parent window 

    int cyVScroll;  // Height of scroll bar arrow 

    HWND hwndPB;    // Handle of progress bar 

    HANDLE hFile;   // Handle of file 

    DWORD cb;       // Size of file and count of

                    // bytes read 

    LPCH pch;       // Address of data read from

                    // file 

    LPCH pchTmp;    // Temporary pointer 


 

    // Ensure that the common control DLL is loaded

    // and create a progress bar along the bottom of

    // the client area of the parent window. 

    // Base the height of the progress bar on the

    // height of a scroll bar arrow. 

    InitCommonControls(); 
    GetClientRect(hwndParent, &rcClient); 
    cyVScroll = GetSystemMetrics(SM_CYVSCROLL); 
    hwndPB = CreateWindowEx(0, PROGRESS_CLASS,
             (LPSTR) NULL, WS_CHILD | WS_VISIBLE,
             rcClient.left, rcClient.bottom
             cyVScroll, rcClient.right, cyVScroll, 
             hwndParent, (HMENU) 0, g_hinst, NULL); 

   // Open the file for reading, and retrieve the

   // size of the file. 


    hFile = CreateFile(lpszFileName, GENERIC_READ,
            FILE_SHARE_READ, (LPSECURITY_ATTRIBUTES)
            NULL, OPEN_EXISTING,
            FILE_ATTRIBUTE_NORMAL, (HANDLE) NULL); 

    if (hFile == (HANDLE) INVALID_HANDLE_VALUE) 
        return FALSE; 

    cb = GetFileSize(hFile, (LPDWORD) NULL); 

    // Set the range and increment of the progress

    // bar. 


    SendMessage(hwndPB, PBM_SETRANGE, 0,
                MAKELPARAM(0, cb / 2048)); 
    SendMessage(hwndPB, PBM_SETSTEP, (WPARAM) 1, 0); 

    // Parse the file. 

    pch = (LPCH) LocalAlloc(LPTR, sizeof(char) *
           2048); 
    pchTmp = pch; 
    do { 
        ReadFile(hFile, pchTmp, sizeof(char) * 2048,
                 &cb, 
            (LPOVERLAPPED) NULL);
        // TODO: Write an error handler to check that all the

        // requested data was read. 

        . 
        . 
        // Include here any code that parses the

        // file. 

        . 
       // Advance the current position of the

       // progress bar by the increment. 

       SendMessage(hwndPB, PBM_STEPIT, 0, 0); 
      } while (cb); 

   CloseHandle((HANDLE) hFile); 
   DestroyWindow(hwndPB);
    
    return TRUE; 
}