Re: help - writing text to a file

On Wed, 11 Apr 2007 20:13:36 -0700, "Tom Serface"
<tom.nospam@camaswood.com> wrote:


To me, it seems that CStdioFile is *not* working with Unicode, but
maybe I'm missing something...

However:
I wrote a simple MFC dialog-based app with a list-box.
I put some Unicode strings into the list-box, and then I save them to
file.

Using both OP's method and CStdioFile fail (when you open the file,
the Chinese Unicode characters aren't there).

Instead, I converted the Unicode (Windows UTF-16) to Unicode UTF-8,
and then wrote the UTF-8 buffer to file.
In this way, I can reopen the file with a text editor, and I can see
the Chinese symbols, too.
(BTW: I wrote "Chinese symbols", but I don't know if they are Chinese
or Japanese or something else from Far East :)

Here's the code main code:

<CODE>
void CTestUnicodeTextDlg::OnBnClickedButton1()
{
   //
   // Put some Unicode strings in list
   //
   std::vector<CString> FileData;
   FileData.push_back(L"Ciao");
   FileData.push_back(L"C:\\Test");

   // UTF-16
   WORD chineseChars[] =
   {
       0x4E09,
       0x4E0B,
       0x4E11,
       0x0000,
   };
   FileData.push_back(CString((LPCWSTR) chineseChars));

   //
   // Show strings
   //
   m_List.ResetContent();
   for ( size_t i = 0; i < FileData.size(); i++ )
   {
       m_List.AddString( FileData.at(i) );
   }

   //
   // Write strings to file
   //

   // *** FAILS ***
   // ...Just writes ANSI...??
   //
   CStdioFile file(
       _T("test_cstdio.txt"),
       CFile::modeCreate | CFile::modeWrite | CFile::typeText
   );
   for( size_t i = 0; i < FileData.size(); i++)
   {
       CString line = FileData.at(i);
       line += L"\n";
       file.WriteString( line );
   }

   //
   // Save in UTF-8 format
   //
   FILE * fout = _wfopen( L"test_utf8.txt", L"wb" );
   for( size_t i = 0; i < FileData.size(); i++)
   {
       // Put the new line (\r\n)
       CString line(FileData.at(i));
       line += L"\r\n";

       // Convert from UTF-16 to UTF-8
       CW2U utf8String( line );

       // Send byte data to output file
       fwrite( (LPSTR) utf8String, 1, strlen(utf8String), fout );
   }
   fclose(fout);
   fout = NULL;
}

</CODE>

And here's the CW2U converter:

<CODE>
//----------------------------------------------------------------------------
// Class: CW2UEX
// Descr: Convert from Unicode UTF-16 (WideChars) to Unicode UTF-8
//----------------------------------------------------------------------------
template< int t_nBufferLength = 128 >
class CW2UEX
{
public:
   CW2UEX( LPCWSTR psz ) throw(...) :
       m_psz( m_szBuffer )
   {
       Init( psz );
   }

   ~CW2UEX() throw()
   {
       if( m_psz != m_szBuffer )
       {
           free( m_psz );
       }
   }

   operator LPSTR() const throw()
   {
       return( m_psz );
   }

private:
   void Init( LPCWSTR psz ) throw(...)
   {
       if (psz == NULL)
       {
           m_psz = NULL;
           return;
       }
       int nLengthW = lstrlenW( psz )+1;

       // One Unicode UTF-16 character could be converted
       // up to 4 UTF-8 characters
       int nLengthUtf8 = nLengthW * 4;

       if( nLengthUtf8 > t_nBufferLength )
       {
           m_psz = static_cast< LPSTR >( malloc(
                     nLengthUtf8*sizeof( char ) ) );
           if (m_psz == NULL)
           {
               AtlThrow( E_OUTOFMEMORY );
           }
       }

       if (::WideCharToMultiByte( CP_UTF8, 0, psz, nLengthW,
           m_psz, nLengthUtf8, NULL, NULL ) == 0)
       {
           AtlThrowLastWin32();
       }
   }

public:
   LPSTR m_psz;
   char m_szBuffer[t_nBufferLength];

private:
   CW2UEX( const CW2UEX& ) throw();
   CW2UEX& operator=( const CW2UEX& ) throw();
};

typedef CW2UEX<> CW2U;

</CODE>

MrAsm