Function FlatStream_LoadBitmap

src/External/CascLib/src/common/FileStream.cpp:1132–1194

}

static bool FlatStream_LoadBitmap(TBlockStream * pStream)
{
    FILE_BITMAP_FOOTER Footer;
    ULONGLONG ByteOffset;
    LPBYTE FileBitmap;
    DWORD BlockCount;
    DWORD BitmapSize;

    // Do not load the bitmap if we should not have to
    if(!(pStream->dwFlags & STREAM_FLAG_USE_BITMAP))
        return false;

    // Only if the size is greater than size of bitmap footer
    if(pStream->Base.File.FileSize > sizeof(FILE_BITMAP_FOOTER))
    {
        // Load the bitmap footer
        ByteOffset = pStream->Base.File.FileSize - sizeof(FILE_BITMAP_FOOTER);
        if(pStream->BaseRead(pStream, &ByteOffset, &Footer, sizeof(FILE_BITMAP_FOOTER)))
        {
            // Make sure that the array is properly BSWAP-ed
            BSWAP_ARRAY32_UNSIGNED((PDWORD)(&Footer), sizeof(FILE_BITMAP_FOOTER));

            // Verify if there is actually a footer
            if(Footer.Signature == ID_FILE_BITMAP_FOOTER && Footer.Version == 0x03)
            {
                // Get the offset of the bitmap, number of blocks and size of the bitmap
                ByteOffset = MAKE_OFFSET64(Footer.MapOffsetHi, Footer.MapOffsetLo);
                BlockCount = (DWORD)(((ByteOffset - 1) / Footer.BlockSize) + 1);
                BitmapSize = ((BlockCount + 7) / 8);

                // Check if the sizes match
                if(ByteOffset + BitmapSize + sizeof(FILE_BITMAP_FOOTER) == pStream->Base.File.FileSize)
                {
                    // Allocate space for the bitmap
                    FileBitmap = CASC_ALLOC<BYTE>(BitmapSize);
                    if(FileBitmap != NULL)
                    {
                        // Load the bitmap bits
                        if(!pStream->BaseRead(pStream, &ByteOffset, FileBitmap, BitmapSize))
                        {
                            CASC_FREE(FileBitmap);
                            return false;
                        }

                        // Update the stream size
                        pStream->BuildNumber = Footer.BuildNumber;
                        pStream->StreamSize = ByteOffset;

                        // Fill the bitmap information
                        pStream->FileBitmap = FileBitmap;
                        pStream->BitmapSize = BitmapSize;
                        pStream->BlockSize  = Footer.BlockSize;
                        pStream->BlockCount = BlockCount;
                        pStream->IsComplete = FlatStream_CheckFile(pStream);
                        return true;
                    }
                }
            }