How To Read a Big Txt File into CEdit and write it as save!.

This problem is important when we want create a NOTEBOOK like Microsoft,some times we must use this teck to use
as logs , and also some other,now it is a usefull solution that have spent much time to get it!
ONE:ReadFile:
void CShowPicDlg::showTXTFile2(CString fileName){
   CWnd *hwnd;
   hwnd=GetDlgItem(IDC_PIC);
   hwnd->ShowWindow(FALSE);
   hwnd=GetDlgItem(IDC_EDIT);
   hwnd->ShowWindow(TRUE);
 
 
 
 
 char *pstrFileName=fileName.GetBuffer(fileName.GetLength());
     BYTE   bySwap ;
     DWORD  dwBytesRead ;
     HANDLE hFile ;
     int    i, iFileLength, iUniTest ;
     PBYTE  pBuffer, pText, pConv ;

          // Open the file.

     if (INVALID_HANDLE_VALUE ==
               (hFile = CreateFile (pstrFileName, GENERIC_READ, FILE_SHARE_READ,
                                    NULL, OPEN_EXISTING, 0, NULL)))
          return  ;

          // Get file size in bytes and allocate memory for read.
          // Add an extra two bytes for zero termination.
                   
     iFileLength = GetFileSize (hFile, NULL) ;
     pBuffer = (unsigned char*)malloc (iFileLength + 2) ;

          // Read file and put terminating zeros at end.
    
     ReadFile (hFile, pBuffer, iFileLength, &dwBytesRead, NULL) ;
     CloseHandle (hFile) ;
     pBuffer[iFileLength] = '\0' ;
     pBuffer[iFileLength + 1] = '\0' ;

          // Test to see if the text is unicode

     iUniTest = IS_TEXT_UNICODE_SIGNATURE | IS_TEXT_UNICODE_REVERSE_SIGNATURE ;
    
     if (IsTextUnicode (pBuffer, iFileLength, &iUniTest))
     {
          pText = pBuffer + 2 ;
          iFileLength -= 2 ;

          if (iUniTest & IS_TEXT_UNICODE_REVERSE_SIGNATURE)
          {
               for (i = 0 ; i < iFileLength / 2 ; i++)
               {
                    bySwap = ((BYTE *) pText) [2 * i] ;
                    ((BYTE *) pText) [2 * i] = ((BYTE *) pText) [2 * i + 1] ;
                    ((BYTE *) pText) [2 * i + 1] = bySwap ;
               }
          }

               // Allocate memory for possibly converted string

          pConv = (unsigned char*)malloc (iFileLength + 2) ;

               // If the edit control is not Unicode, convert Unicode text to
               // non-Unicode (ie, in general, wide character).

#ifndef UNICODE
          WideCharToMultiByte (CP_ACP, 0, (PWSTR) pText, -1, (char*)pConv,
                               iFileLength + 2, NULL, NULL) ;

               // If the edit control is Unicode, just copy the string
#else
          lstrcpy ((PTSTR) pConv, (PTSTR) pText) ;
#endif

     }
     else      // the file is not Unicode
     {
          pText = pBuffer ;

               // Allocate memory for possibly converted string.

          pConv = (unsigned char*)malloc (2 * iFileLength + 2) ;

               // If the edit control is Unicode, convert ASCII text.

#ifdef UNICODE
          MultiByteToWideChar (CP_ACP, 0, pText, -1, (PTSTR) pConv,
                               iFileLength + 1) ;

               // If not, just copy buffer
#else
          lstrcpy ((PTSTR) pConv, (PTSTR) pText) ;
#endif
     }
     //hwndEdit=m_edit.m_hWnd;
     //SetWindowText (hwndEdit, (PTSTR) pConv) ;
  ::SetWindowText (m_edit.m_hWnd, (PTSTR) pConv) ;
     free (pBuffer) ;
     free (pConv) ;
}

void CShowPicDlg::writeTXTFile(CString fileName)
{   
     char *pstrFileName=fileName.GetBuffer(fileName.GetLength());

     DWORD  dwBytesWritten ;
     HANDLE hFile ;
     int    iLength ;
     PTSTR  pstrBuffer ;
     WORD   wByteOrderMark = 0xFEFF ;

          // Open the file, creating it if necessary
    
     if (INVALID_HANDLE_VALUE ==
               (hFile = CreateFile (pstrFileName, GENERIC_WRITE, 0,
                                    NULL, CREATE_ALWAYS, 0, NULL)))
          return  ;

          // Get the number of characters in the edit control and allocate
          // memory for them.
    
     //iLength = GetWindowTextLength (hwndEdit) ;
  iLength = ::GetWindowTextLength (m_edit.m_hWnd) ;
     pstrBuffer = (PTSTR) malloc ((iLength + 1) * sizeof (TCHAR)) ;
    
     if (!pstrBuffer)
     {
          CloseHandle (hFile) ;
          return  ;
     }

          // If the edit control will return Unicode text, write the
          // byte order mark to the file.

#ifdef UNICODE
     WriteFile (hFile, &wByteOrderMark, 2, &dwBytesWritten, NULL) ;
#endif

          // Get the edit buffer and write that out to the file.
    
     //GetWindowText (hwndEdit, pstrBuffer, iLength + 1) ;
  ::GetWindowText (m_edit.m_hWnd, pstrBuffer, iLength + 1) ;
     WriteFile (hFile, pstrBuffer, iLength * sizeof (TCHAR),
                &dwBytesWritten, NULL) ;
    
     if ((iLength * sizeof (TCHAR)) != (int) dwBytesWritten)
     {
          CloseHandle (hFile) ;
          free (pstrBuffer) ;
          return  ;
     }
    
     CloseHandle (hFile) ;
     free (pstrBuffer) ;
}