bool Flush(OggPage og, bool force, int fill)
{
int maxvals = Math.Min(LacingFill, 0xFF);
if (0 == maxvals)
{
return(false);
}
// construct a page
// decide how many segments to include
int vals = 0;
int acc = 0;
long granule_pos = -1;
// If this is the initial header case, the first page must only include
// the initial header packet
if (!BoS) // 'initial header page' case
{
granule_pos = 0;
for (vals = 0; vals < maxvals; vals++)
{
if ((LacingVals[vals] & 0xFF) < 0xFF)
{
vals++;
break;
}
}
}
else
{
int packets_done = 0;
int packet_just_done = 0;
for (vals = 0; vals < maxvals; vals++)
{
if (acc > fill && packet_just_done >= 4)
{
force = true;
break;
}
acc += LacingVals[vals] & 0xFF;
if ((LacingVals[vals] & 0xFF) < 0xFF)
{
granule_pos = GranuleVals[vals];
packet_just_done = ++packets_done;
}
else
{
packet_just_done = 0;
}
}
if (0xFF == vals)
{
force = true;
}
}
if (!force)
{
return(false);
}
// construct the header in temp storage
Encoding.ASCII.GetBytes("OggS", 0, 4, Header, 0);
// stream structure version
Header[4] = 0;
// continued packet flag?
Header[5] = 0;
if ((LacingVals[0] & 0x100) == 0)
{
Header[5] |= 1;
}
// first page flag?
if (!BoS)
{
Header[5] |= 2;
}
// last page flag?
if (EoS && LacingFill == vals)
{
Header[5] |= 4;
}
BoS = true;
// 64 bits of PCM position
LittleEndian.Pack(granule_pos, Header, 6);
// 32 bits of stream serial number
LittleEndian.Pack(SerialNo, Header, 14);
// 32 bits of page counter (we have both counter and page header because this
// val can roll over)
if (-1 == PageNo)
{
PageNo = 0;
}
LittleEndian.Pack(PageNo, Header, 18);
++PageNo;
int bytes = 0;
// segment table
Header[26] = (byte)vals;
for (int i = 0; i < vals; ++i)
{
bytes += Header[i + 27] = (byte)LacingVals[i];
}
// set pointers in the ogg_page struct
og.Header = Header;
og.HeaderLength = HeaderFill = vals + 27;
og.Body = BodyData;
og.BodyStart = BodyReturned;
og.BodyLength = bytes;
// advance the lacing data and set the body_returned pointer
LacingFill -= vals;
Array.Copy(LacingVals, vals, LacingVals, 0, LacingFill);
Array.Copy(GranuleVals, vals, GranuleVals, 0, LacingFill);
BodyReturned += bytes;
// calculate the checksum
og.SetChecksum();
return(true);
}
public bool PageOut(OggPage page)
{
bool force = EoS && (LacingFill > 0) || (LacingFill > 0 && !BoS);
return(Flush(page, force, 0x1000));
}
