indexStream = d.openInput(indexStreamFN, context);
format = indexStream.readInt();
if (format < FORMAT_MINIMUM)
throw new IndexFormatTooOldException(indexStream, format, FORMAT_MINIMUM, FORMAT_CURRENT);
if (format > FORMAT_CURRENT)
throw new IndexFormatTooNewException(indexStream, format, FORMAT_MINIMUM, FORMAT_CURRENT);
final long indexSize = indexStream.length() - FORMAT_SIZE;