public bool TryReadPage(out OggPage page)
{
OggReadPageResult result;
do
{
result = ReadPageInternal(out page);
}
while (result == OggReadPageResult.Repeat);
return result == OggReadPageResult.Success;
}
private OggReadPageResult ReadPageInternal(out OggPage page)
{
page = null;
if (headerBytes == 0)
{
if (filled < 27)
return OggReadPageResult.NeedMoreData;
if (data[0] != 'O' ||
data[1] != 'g' ||
data[2] != 'g' ||
data[3] != 'S')
{
return Resynchronize();
}
int hbytes = data[26] + 27;
if (filled < hbytes)
return OggReadPageResult.NeedMoreData;
headerBytes = hbytes;
for (int i = 0; i < (int)data[26]; ++i)
{
bodyBytes += data[27 + i];
}
}
if (headerBytes + bodyBytes <= filled)
{
// Check the CRC.
// Have to temporarily zero out the CRC field first, though.
byte crc0, crc1, crc2, crc3;
crc0 = data[22];
crc1 = data[23];
crc2 = data[24];
crc3 = data[25];
data[22] = 0;
data[23] = 0;
data[24] = 0;
data[25] = 0;
uint actualCrc = OggCrc32.Compute(data, 0, headerBytes + bodyBytes);
data[22] = crc0;
data[23] = crc1;
data[24] = crc2;
data[25] = crc3;
if (crc0 != (byte)(actualCrc & 0xFF) ||
crc1 != (byte)((actualCrc >> 8) & 0xFF) ||
crc2 != (byte)((actualCrc >> 16) & 0xFF) ||
crc3 != (byte)((actualCrc >> 24) & 0xFF))
{
Console.WriteLine("CRC fail!");
return Resynchronize();
}
page = new OggPage();
byte headerType = data[5];
page.Continuation = (headerType & 0x1) != 0;
page.BeginningOfStream = (headerType & 0x2) != 0;
page.EndOfStream = (headerType & 0x4) != 0;
page.GranulePosition = BitConverter.ToUInt64(data, 6);
page.BitstreamSerialNumber = BitConverter.ToUInt32(data, 14);
page.PageSequenceNumber = BitConverter.ToUInt32(data, 18);
// TODO: Copy page bytes
// TODO: Return the page somehow
/*Console.WriteLine("---------------------------------");
Console.WriteLine("Header Bytes: {0}", headerBytes);
Console.WriteLine("Body Bytes: {0}", bodyBytes);
Console.WriteLine("Incomplete: {0}", data[headerBytes - 1] == 255);
Console.WriteLine("Continuation: {0}", page.Continuation);
Console.WriteLine("BeginningOfStream: {0}", page.BeginningOfStream);
Console.WriteLine("EndOfStream: {0}", page.EndOfStream);
Console.WriteLine("GranulePosition: {0}", page.GranulePosition);
Console.WriteLine("BitstreamSerialNumber: {0}", page.BitstreamSerialNumber);
Console.WriteLine("PageSequenceNumber: {0}", page.PageSequenceNumber);
Console.WriteLine("CRC: {0:X8}", actualCrc);
Console.WriteLine();
Console.WriteLine("Segment count: {0}", data[26]);
Console.WriteLine("Segment table:");
Util.DumpBytes(data, 27, headerBytes - 27);
Console.WriteLine();
Console.WriteLine("Body:");
Util.DumpBytes(data, headerBytes, bodyBytes);*/
// TODO: Share buffers instead
int numSegments = headerBytes - 27;
page.SegmentTable = new byte[numSegments];
Array.Copy(data, 27, page.SegmentTable, 0, numSegments);
page.Data = new byte[bodyBytes];
Array.Copy(data, headerBytes, page.Data, 0, bodyBytes);
TrimFront(headerBytes + bodyBytes);
headerBytes = 0;
bodyBytes = 0;
return OggReadPageResult.Success;
}
else
return OggReadPageResult.NeedMoreData;
}