public static WritingContext StartWriting(MemoryCursor cursor,
AckDelay delay,
PacketNumber largestAcknowledged,
int beforLargestAcknowledgedLength,
AckEcnCounts?ecnFeedback = null)
{
if (beforLargestAcknowledgedLength < 0)
{
throw new EncodingException();
}
FrameType
.CreateAck(ecnFeedback.HasValue)
.Write(cursor);
largestAcknowledged.WriteVariable(cursor);
delay.Write(cursor);
var startPayloadOffset = cursor.AsOffset();
cursor.EncodeVariable32(beforLargestAcknowledgedLength);
var startRangesOffset = cursor.AsOffset();
return(new WritingContext(cursor, ecnFeedback, startPayloadOffset, startRangesOffset));
}
private AckFrame(AckDelay delay,
PacketNumber largestAcknowledged,
AckRanges ranges,
AckEcnCounts?ecnFeedback)
{
Delay = delay;
LargestAcknowledged = largestAcknowledged;
Ranges = ranges;
EcnFeedback = ecnFeedback;
}
public static bool TryParse(MemoryCursor cursor, out AckFrame result)
{
result = new AckFrame();
var type = FrameType.Peek(cursor);
if (!type.IsAck)
{
return(false);
}
type.Slice(cursor);
var largestAcknowledged = PacketNumber.ParseVariable(cursor);
var delay = AckDelay.Parse(cursor);
var rangesCount = cursor.DecodeVariable32();
var ranges = SliceRanges(cursor, rangesCount + 1);
var ecnFeedback = type.HasAckEcnFeedback ? AckEcnCounts.Parse(cursor) : new AckEcnCounts?();
result = new AckFrame(delay, largestAcknowledged, ranges, ecnFeedback);
return(true);
}