private int ReceiveFromPkgBuffer()

in rd-net/RdFramework/Impl/SocketWire.cs [236:306]
61 lines of code
11 McCabe index (conditional complexity)

      private int ReceiveFromPkgBuffer(byte[] buffer, int offset, int size)
      {
        //size > 0

        if (myPkg.Available > 0)
        {
          var sizeToCopy = Math.Min(size, myPkg.Available);
          myPkg.MoveTo(buffer, offset, sizeToCopy);
          return sizeToCopy;
        }
        else
        {
          while (true)
          {
            myPkgHeaderBuffer.Clear();
            if (!myPkgHeaderBuffer.Read(ref mySocketBuffer, ReceiveFromSocket))
              return 0;

            Int32 len = UnsafeReader.ReadInt32FromBytes(myPkgHeaderBuffer.Data);

            if (len == PING_LEN)
            {
              Int32 receivedTimestamp = UnsafeReader.ReadInt32FromBytes(myPkgHeaderBuffer.Data, sizeof(Int32));
              Int32 receivedCounterpartTimestamp = UnsafeReader.ReadInt32FromBytes(myPkgHeaderBuffer.Data, sizeof(Int32) + sizeof(Int32));
              myCounterpartTimestamp = receivedTimestamp;
              myCounterpartNotionTimestamp = receivedCounterpartTimestamp;

              if (ConnectionEstablished(myCurrentTimeStamp, myCounterpartNotionTimestamp))
              {
                if (!HeartbeatAlive.Value) // only on change
                {
                  Log.WhenTrace()?.Log($"Connection is alive after receiving PING {Id}: " +
                                       $"receivedTimestamp: {receivedTimestamp}, " +
                                       $"receivedCounterpartTimestamp: {receivedCounterpartTimestamp}, " +
                                       $"currentTimeStamp: {myCurrentTimeStamp}, " +
                                       $"counterpartTimestamp: {myCounterpartTimestamp}, " +
                                       $"counterpartNotionTimestamp: {myCounterpartNotionTimestamp}");
                }
                HeartbeatAlive.Value = true;
              }

              continue;
            }

            Int64 seqN = UnsafeReader.ReadInt64FromBytes(myPkgHeaderBuffer.Data, sizeof(Int32));
            if (len == ACK_MSG_LEN)
            {
              SendBuffer.Acknowledge(seqN);
            }
            else
            {

              myPkg.Clear();
              if (!myPkg.Read(ref mySocketBuffer, ReceiveFromSocket, len))
                return 0;

              if (seqN > myMaxReceivedSeqn || seqN == 1 /*TODO new client, possible duplicate problem if ack for seqN=1 from previous client's connection hasn't passed*/)
              {
                myMaxReceivedSeqn = seqN; //will be acknowledged when we read whole message
                Assertion.Assert(myPkg.Available > 0);

                var sizeToCopy = Math.Min(size, myPkg.Available);
                myPkg.MoveTo(buffer, offset, sizeToCopy);
                return sizeToCopy;
              }
              else
                myAcktor.SendAsync(seqN);
            }
          }
        }
      }