bool PacketBuffer::seekTo(double seek_pos, bool backwards)
{
if (isEmpty())
return true;
if (backwards && at(0).ts > seek_pos)
{
if (floor(at(0).ts) > seek_pos)
return false; //Brak paczek do skoku w tył
seek_pos = at(0).ts;
}
double durationToChange = 0.0;
qint64 sizeToChange = 0;
if (!backwards) //Skok do przodu
{
const int count = packetsCount();
for (int i = pos; i < count; ++i)
{
const Packet &pkt = at(i);
if (pkt.ts < seek_pos || !pkt.hasKeyFrame)
{
durationToChange += pkt.duration;
sizeToChange += pkt.size();
}
else
{
remaining_duration -= durationToChange;
backward_duration += durationToChange;
remaining_bytes -= sizeToChange;
backward_bytes += sizeToChange;
pos = i;
return true;
}
}
}
else for (int i = pos - 1; i >= 0; --i) //Skok do tyłu
{
const Packet &pkt = at(i);
durationToChange += pkt.duration;
sizeToChange += pkt.size();
if (pkt.hasKeyFrame && pkt.ts <= seek_pos)
{
remaining_duration += durationToChange;
backward_duration -= durationToChange;
remaining_bytes += sizeToChange;
backward_bytes -= sizeToChange;
pos = i;
return true;
}
}
return false;
}
inline int remainingPacketsCount() const
{
return packetsCount() - pos;
}