Need a strict boundary check for resolved?

[spacewander]

In https://github.com/ipipdotnet/ipdb-c/blob/master/ipdb.c#L142:

if (resolved >= reader->file_size) {
        return ErrDatabaseError;
    }

int size = (reader->data[resolved] << 8) | reader->data[resolved + 2];

Maybe we need to replace resolved >= reader->file_size with resolved >= reader->data_size, because the boundary of reader->data is data_size not file_size.