private int extractData(TiffDirEntry dir)
{
int type = (int)dir.tdir_type;
if (m_header.tiff_magic == TIFF_BIGENDIAN)
return (int)((dir.tdir_offset >> m_typeshift[type]) & m_typemask[type]);
return (int)(dir.tdir_offset & m_typemask[type]);
}