Function PartStream_LoadBitmap

src/External/CascLib/src/common/FileStream.cpp:1518–1580

}

static bool PartStream_LoadBitmap(TBlockStream * pStream)
{
    PPART_FILE_MAP_ENTRY FileBitmap;
    PART_FILE_HEADER PartHdr;
    ULONGLONG ByteOffset = 0;
    ULONGLONG StreamSize = 0;
    DWORD BlockCount;
    DWORD BitmapSize;

    // Only if the size is greater than size of the bitmap header
    if(pStream->Base.File.FileSize > sizeof(PART_FILE_HEADER))
    {
        // Attempt to read PART file header
        if(pStream->BaseRead(pStream, &ByteOffset, &PartHdr, sizeof(PART_FILE_HEADER)))
        {
            // We need to swap PART file header on big-endian platforms
            BSWAP_ARRAY32_UNSIGNED(&PartHdr, sizeof(PART_FILE_HEADER));

            // Verify the PART file header
            if(IsPartHeader(&PartHdr))
            {
                // Get the number of blocks and size of one block
                StreamSize = MAKE_OFFSET64(PartHdr.FileSizeHi, PartHdr.FileSizeLo);
                ByteOffset = sizeof(PART_FILE_HEADER);
                BlockCount = (DWORD)((StreamSize + PartHdr.BlockSize - 1) / PartHdr.BlockSize);
                BitmapSize = BlockCount * sizeof(PART_FILE_MAP_ENTRY);

                // Check if sizes match
                if((ByteOffset + BitmapSize) < pStream->Base.File.FileSize)
                {
                    // Allocate space for the array of PART_FILE_MAP_ENTRY
                    FileBitmap = CASC_ALLOC<PART_FILE_MAP_ENTRY>(BlockCount);
                    if(FileBitmap != NULL)
                    {
                        // Load the block map
                        if(!pStream->BaseRead(pStream, &ByteOffset, FileBitmap, BitmapSize))
                        {
                            CASC_FREE(FileBitmap);
                            return false;
                        }

                        // Make sure that the byte order is correct
                        BSWAP_ARRAY32_UNSIGNED(FileBitmap, BitmapSize);

                        // Update the stream size
                        pStream->BuildNumber = StringToInt(PartHdr.GameBuildNumber);
                        pStream->StreamSize = StreamSize;

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