bool DecodeBMP(CDataSourceABC &ds, CFrameArray &arrFrames, SIZE &size )
{
// Attempt to read and verify the signature by reading the file header
BITMAPFILEHEADER bmf;
BITMAPINFOHEADER infoHeader;
DWORD offBits = 0;
DWORD headerSize;
bool isCoreFile;
CDib* pDib = 0;
try {
if ( !ds.ReadBytes((BYTE*)&bmf, sizeof(BITMAPFILEHEADER)) )
throw 1;
// Determine if it has a BITMAPFILEHEADER
if (bmf.bfType != 0x4d42)
{
ds.Reset();
}
else
{
// Save offset from file header, if it makes sense
if (bmf.bfOffBits)
offBits = bmf.bfOffBits - sizeof(BITMAPFILEHEADER);
}
// Read the header size, and validate
if ( !ds.ReadBytes((BYTE*)&headerSize, sizeof(DWORD)) ||
(headerSize != sizeof(BITMAPINFOHEADER) &&
headerSize != sizeof(BITMAPCOREHEADER) ) )
throw 1;
isCoreFile = (headerSize == sizeof(BITMAPCOREHEADER));
// Prepare the header structure, correcting possible errors in the file
infoHeader.biSize = sizeof(BITMAPINFOHEADER);
// If its a core bitmap, convert the header
if (isCoreFile)
{
BITMAPCOREHEADER coreHeader;
if ( !ds.ReadBytes((BYTE*)&coreHeader.bcWidth, sizeof(BITMAPCOREHEADER) - sizeof(DWORD)) )
throw 1;
ConvertCoreHeader(&coreHeader, &infoHeader);
}
else
{
if( !ds.ReadBytes((BYTE*)&infoHeader.biWidth,
sizeof(BITMAPINFOHEADER) - sizeof(DWORD)) )
throw 1;
}
pDib = new CDib(&infoHeader);
// Read the masks
if (pDib->GetMaskTable())
{
if ( !ds.ReadBytes((BYTE*)pDib->GetMaskTable(), 3 * sizeof(DWORD)) )
throw 1;
}
// Calculate number of colors in color table
if (pDib->GetColorTable())
{
int colors = pDib->GetColorsUsed();
// Calculate size of color table to read
int colorsize = colors *
( isCoreFile ? sizeof(RGBTRIPLE) : sizeof(RGBQUAD));
if ( !ds.ReadBytes((BYTE*)pDib->GetColorTable(), colorsize) )
throw 1;
if (isCoreFile)
ConvertCoreColors(pDib->GetColorTable(), colors);
}
// Skip bits if necessary
DWORD curPos = ds.GetCurrentPos();
if (offBits && (DWORD)offBits > curPos)
ds.SetRelativePos(offBits - curPos);
if ( !ds.ReadBytes(pDib->GetBits(), pDib->GetAllocatedImageSize()) )
throw 1;
size.cx = pDib->GetWidth();
size.cy = pDib->GetHeight();
CFrame *pFrame = new CFrame( pDib, 0 );
arrFrames.Add( pFrame );
}
catch (...)
{
if( pDib )
{
delete pDib;
pDib = NULL;
}
}
if( pDib )
return true;
return false;
}
