private OggPage ReadPage()
{
byte[] pageHeaderData;
if (stream.ReadBytes(out pageHeaderData, 27) < 27)
{
return(null);
}
string magic = System.Text.Encoding.UTF8.GetString(pageHeaderData, 0, 4);
if (magic != "OggS")
{
return(null);
}
byte version = pageHeaderData[4];
OggPageType type = (OggPageType)pageHeaderData[5];
byte[] granule = new byte[8];
Array.Copy(pageHeaderData, 6, granule, 0, 8);
//Buffer.BlockCopy (pageHeaderData, 6, granule, 0, 8);
int streamSerialNumber = BitConverter.ToInt32(pageHeaderData, 14);
int pageSequenceNumber = BitConverter.ToInt32(pageHeaderData, 18);
int checksum = BitConverter.ToInt32(pageHeaderData, 22);
byte segments = pageHeaderData[26];
byte[] segmentLengths = new byte[segments];
if (stream.ReadBytes(out segmentLengths, segments) < segments)
{
return(null);
}
byte[][] data = new byte[segmentLengths.Length][];
for (int i = 0; i < segmentLengths.Length; ++i)
{
byte len = segmentLengths[i];
byte[] segment;
if (stream.ReadBytes(out segment, len) != len)
{
return(null);
}
data[i] = segment;
}
OggPage page = new OggPage(streamSerialNumber, pageSequenceNumber);
page.Type = type;
page.Version = version;
page.Segments = data;
page.Granule = granule;
return(page);
}
List <byte> pageBytes = new List <byte>(); //For checksum check
private List <byte[]> ReadPage(Stream stream, out OggPageType type)
{
pageBytes.Clear();
ReadUntilMagic(stream); //Magic word
pageBytes.AddRange(magic);
var vn = stream.ReadByte(); //Ogg version number (0)
pageBytes.Add((byte)vn);
var packetFlag = stream.ReadByte(); //Packet flag
pageBytes.Add((byte)packetFlag);
type = (OggPageType)packetFlag;
var granulePosition = ReadBytes(stream, 8); //Granule position
pageBytes.AddRange(granulePosition);
var streamSN = ReadBytes(stream, 4);
pageBytes.AddRange(streamSN);
var pageSN = ReadBytes(stream, 4);
pageBytes.AddRange(pageSN);
var crc = ReadBytes(stream, 4);
pageBytes.AddRange(new byte[] { 0, 0, 0, 0 });
var segmentCount = stream.ReadByte(); //Number of segments in this page, 0-255
pageBytes.Add((byte)segmentCount);
int[] segmentLengths = new int[segmentCount];
//Read segment table
for (int i = 0; i < segmentCount; i++)
{
segmentLengths[i] = stream.ReadByte();
pageBytes.Add((byte)segmentLengths[i]);
}
List <byte[]> data = new List <byte[]>();
//Read segments
for (int i = 0; i < segmentCount; i++)
{
byte[] segmentBytes = ReadBytes(stream, segmentLengths[i]);
pageBytes.AddRange(segmentBytes);
buffer.AddRange(segmentBytes);
if (segmentLengths[i] < 255)
{
data.Add(buffer.ToArray());
buffer.Clear();
}
}
//Skip page if CRC does not match
uint calculatedCrc = CalculateChecksum(pageBytes);
if (calculatedCrc != BitConverter.ToUInt32(crc, 0))
{
return(new List <byte[]>());
}
return(data);
}
