C / C++ / MFC

StringCchPrintfA(pszFilename,1024,"hello.bmp");
	// Attempt to open the Dib file for reading.
	if( !cf.Open( pszFilename, CFile::modeRead ) )
	{
		StringCchPrintfA(message,1024,"error reading file");
		MessageBox(NULL, message, "Textures.exe", MB_OK);
		return( FALSE );
	}
		

	// Get the size of the file and store
	// in a local variable. Subtract the
	// size of the BITMAPFILEHEADER structure
	// since we won't keep that in memory.
	DWORD dwDibSize= cf.GetLength() - sizeof( BITMAPFILEHEADER );
	int bsize =0;
	//dwDibSize =
	bsize=	cf.GetLength() - sizeof( BITMAPFILEHEADER );
	StringCchPrintfA(message,1024,"bitmap size  %d",bsize);
	MessageBox(NULL, message, "Textures.exe", MB_OK);

	// Attempt to allocate the Dib memory.
	unsigned char *pDib;
	pDib = new unsigned char [dwDibSize];
	if( pDib == NULL )
	{
			StringCchPrintfA(message,1024,"error allocating array ");
				MessageBox(NULL, message, "Textures.exe", MB_OK);
				return( FALSE );
	}
		

	BITMAPFILEHEADER BFH;

	// Read in the Dib header and data.
	try{

		// Did we read in the entire BITMAPFILEHEADER?
		if( cf.Read( &BFH, sizeof( BITMAPFILEHEADER ) )
			!= sizeof( BITMAPFILEHEADER ) ||

			// Is the type 'MB'?
			BFH.bfType != 'MB' ||

			// Did we read in the remaining data?
			cf.Read( pDib, dwDibSize ) != dwDibSize )
			{
				StringCchPrintfA(message,1024,"error processing the file ");
				MessageBox(NULL, message, "Textures.exe", MB_OK);
			// Delete the memory if we had any
			// errors and return FALSE.
			delete [] pDib;
			return( FALSE );
			}
		}

StringCchPrintfA(message,1024,"dib at 34 %d",pDib[34]);
	MessageBox(NULL, message, "Textures.exe", MB_OK);

m_pDib = pDib;
	m_dwDibSize = dwDibSize;

	// Pointer our BITMAPINFOHEADER and RGBQUAD
	// variables to the correct place in the Dib data.
	m_pBIH = (BITMAPINFOHEADER *) m_pDib;
	m_pPalette =
		(RGBQUAD *) &m_pDib[sizeof(BITMAPINFOHEADER)];

	//	get image width and height
	m_width = m_pBIH->biWidth;
	m_height = m_pBIH->biHeight;

	// Calculate the number of palette entries.
	m_nPaletteEntries = 1 << m_pBIH->biBitCount;
	if( m_pBIH->biBitCount > 8 )
		m_nPaletteEntries = 0;
	else if( m_pBIH->biClrUsed != 0 )
		m_nPaletteEntries = m_pBIH->biClrUsed;

	// Point m_pDibBits to the actual Dib bits data.
	m_pDibBits =
		&m_pDib[sizeof(BITMAPINFOHEADER)+
			m_nPaletteEntries*sizeof(RGBQUAD)];

	// If we have a valid palette, delete it.
	if( m_Palette.GetSafeHandle() != NULL )
		m_Palette.DeleteObject();

// Calculate the number of palette entries.
m_nPaletteEntries = 1 << m_pBIH->biBitCount;
if( m_pBIH->biBitCount > 8 )
    m_nPaletteEntries = 0;
else if( m_pBIH->biClrUsed != 0 )
    m_nPaletteEntries = m_pBIH->biClrUsed;

cf.Read( &BFH, sizeof( BITMAPFILEHEADER ) 

fearless_ wrote:

What does the line that has the overload operator do?

m_nPaletteEntries = 1 << m_pBIH->biBitCount;

m_nPaletteEntries = pow(2, m_pBIH->biBitCount); // 2 to the power of bpp