internal override void Parse()

in src/Proton.TestPeer/Driver/FrameDecoder.cs [308:397]
74 lines of code
9 McCabe index (conditional complexity)

         internal override void Parse(Stream input)
         {
            uint dataOffset = (uint)((input.ReadByte() << 2) & 0x3FF);
            uint frameSize = (uint)(this.frameSize + FRAME_SIZE_BYTES);

            ValidateDataOffset(dataOffset, frameSize);

            int type = input.ReadByte() & 0xFF;
            ushort channel = input.ReadUnsignedShort();

            // note that this skips over the extended header if it's present
            if (dataOffset != 8)
            {
               input.Position = input.Position + dataOffset - 8;
            }

            uint frameBodySize = frameSize - dataOffset;

            byte[] payload = null;
            object val = null;

            if (frameBodySize > 0)
            {
               uint frameBodyStartIndex = (uint)input.Position;

               try
               {
                  decoder.codec.Decode(input);
               }
               catch (Exception e)
               {
                  throw new Exception("Decoder failed reading remote input:", e);
               }

               DataType dataType = decoder.codec.DataType;
               if (dataType != DataType.Described)
               {
                  throw new ArgumentException(
                      "Frame body type expected to be " + DataType.Described + " but was: " + dataType);
               }

               try
               {
                  val = decoder.codec.GetDescribedType();
               }
               finally
               {
                  decoder.codec.Clear();
               }

               // Slice to the known Frame body size and use that as the buffer for any payload once
               // the actual Performative has been decoded.  The implies that the data comprising the
               // performative will be held as long as the payload buffer is kept.
               if (input.Position < input.Length)
               {
                  // Check that the remaining bytes aren't part of another frame.
                  uint payloadSize = (uint)(frameBodySize - (input.Position - frameBodyStartIndex));
                  if (payloadSize > 0)
                  {
                     payload = input.ReadBytes((int)payloadSize);
                  }
               }
            }
            else
            {
               decoder.logger.LogTrace("{} Read: CH[{}] : Heartbeat [{}]", frameHandler.Name, channel, payload);
               decoder.TransitionToFrameSizeParsingStage();
               frameHandler.HandleHeartbeat(frameSize, channel);
               return;
            }

            if (type == AMQP_FRAME_TYPE)
            {
               PerformativeDescribedType performative = (PerformativeDescribedType)val;
               decoder.logger.LogTrace("{} Read: CH[{}] : {} [{}]", frameHandler.Name, channel, performative, payload);
               decoder.TransitionToFrameSizeParsingStage();
               frameHandler.HandlePerformative(frameSize, performative, channel, payload);
            }
            else if (type == SASL_FRAME_TYPE)
            {
               SaslDescribedType performative = (SaslDescribedType)val;
               decoder.logger.LogTrace("{} Read: {} [{}]", frameHandler.Name, performative, payload);
               decoder.TransitionToFrameSizeParsingStage();
               frameHandler.HandleSaslPerformative(frameSize, performative, channel, payload);
            }
            else
            {
               throw new ArgumentException(string.Format("unknown frame type: {0}", type));
            }
         }