Blob(long len, Stream stream)
{
if (len < 0)
{
throw new ArgumentOutOfRangeException();
}
long startPosition = stream.Position;
trackNumber = checked ((byte)stream.readUint4());
Span <byte> buffer = stackalloc byte[3];
stream.read(buffer);
timestamp = BinaryPrimitives.ReadInt16BigEndian(buffer);
flags = (eBlockFlags)buffer[2];
long currentPosition = stream.Position;
position = currentPosition;
length = checked ((int)(len - (currentPosition - startPosition)));
}
public static void unpackFrames(this Stream stream, ref Blob blob, ref LacedFrames laced)
{
eBlockFlags lacing = blob.lacing;
if (lacing == eBlockFlags.NoLacing)
{
// laced.frames?.Clear();
laced.lacing = eLacingResult.NoLacing;
return;
}
stream.Seek(blob.position, SeekOrigin.Begin);
int lacingHeader;
if (blob.length <= maxBuffer)
{
if (null != laced.buffer)
{
if (laced.buffer.Length < blob.length)
{
laced.buffer = new byte[blob.length];
}
}
else
{
laced.buffer = new byte[blob.length];
}
stream.read(laced.buffer.AsSpan().Slice(0, blob.length));
lacingHeader = laced.buffer[0];
laced.lacing = eLacingResult.Buffered;
}
else
{
lacingHeader = stream.ReadByte();
if (lacingHeader < 0)
{
throw new EndOfStreamException();
}
laced.lacing = eLacingResult.Large;
}
int lacedBlocksCount = lacingHeader + 1;
laced.initialize(lacedBlocksCount);
switch (lacing)
{
case eBlockFlags.FixedSize:
int cbPayload = blob.length - 1;
if (0 != cbPayload % lacedBlocksCount)
{
throw new ArgumentException($"Error in the MKV file, blob header specifies fixed size lacing with { lacedBlocksCount } laced frames, yet the block payload size { cbPayload } ain’t divisible");
}
int cbFrame = cbPayload / lacedBlocksCount;
for (int i = 0; i < lacedBlocksCount; i++)
{
laced.add(1 + cbFrame * i, cbFrame);
}
return;
case eBlockFlags.EBML:
if (laced.lacing == eLacingResult.Buffered)
{
unpackEbmlFromBuffer(lacedBlocksCount, laced.buffer.AsSpan().Slice(0, blob.length), ref laced);
}
else
{
unpackEbmlFromStream(lacedBlocksCount, stream, blob.length, ref laced);
}
break;
default:
throw new NotImplementedException($"{ lacing } lacing is not implemented");
}
}
