end = offset;
// We get the offset for the last page of the physical bitstream.
// Most OggVorbis files will contain a single logical bitstream
end = get_prev_page(og);
// moer than one logical bitstream?
if (og.serialno() != serialno) {
// Chained bitstream. Bisect-search each logical bitstream
// section. Do so based on serial number only
if (bisect_forward_serialno(0, 0, end + 1, serialno, 0) < 0) {
clear();
return OV_EREAD;