protected override bool MatchesSafely()

in src/Proton.TestPeer/Matchers/Types/Messaging/CompositingDataSectionMatcher.cs [70:139]
58 lines of code
14 McCabe index (conditional complexity)

      protected override bool MatchesSafely(Stream receivedBinary)
      {
         if (expectDataSectionPreamble)
         {
            object descriptor = ReadDescribedTypeEncoding(receivedBinary);

            if (!(DescriptorCode.Equals(descriptor) || DescriptorSymbol.Equals(descriptor)))
            {
               return false;
            }

            // Should be a Binary AMQP type with a length value and possibly some bytes
            EncodingCodes encodingCode = receivedBinary.ReadEncodingCode();

            if (encodingCode == EncodingCodes.VBin8)
            {
               expectedCurrentDataSectionBytes = receivedBinary.ReadUnsignedByte();
            }
            else if (encodingCode == EncodingCodes.VBin32)
            {
               expectedCurrentDataSectionBytes = receivedBinary.ReadInt();
            }
            else
            {
               decodingErrorDescription = "Expected to read a Binary Type but read encoding code: " + encodingCode;
               return false;
            }

            if (expectedCurrentDataSectionBytes > expectedRemainingBytes)
            {
               decodingErrorDescription = "Expected encoded Binary to indicate size of: " + expectedRemainingBytes + ", " +
                                          "or less but read an encoded size of: " + expectedCurrentDataSectionBytes;
               return false;
            }

            expectDataSectionPreamble = false;  // We got the current preamble
         }

         if (expectedRemainingBytes != 0)
         {
            int currentChunkSize = Math.Min(expectedCurrentDataSectionBytes, (int)receivedBinary.ReadableBytes());

            byte[] expectedValueChunk = expectedValueStream.ReadBytes(currentChunkSize);
            byte[] currentChunk = receivedBinary.ReadBytes(currentChunkSize);

            if (!expectedValueChunk.SequenceEqual(currentChunk))
            {
               return false;
            }

            expectedRemainingBytes -= currentChunkSize;
            expectedCurrentDataSectionBytes -= currentChunkSize;

            if (expectedRemainingBytes != 0 && expectedCurrentDataSectionBytes == 0)
            {
               expectDataSectionPreamble = true;
               expectedCurrentDataSectionBytes = -1;
            }
         }

         if (expectedRemainingBytes == 0 && receivedBinary.IsReadable() && !ExpectTrailingBytes)
         {
            unexpectedTrailingBytes = true;
            return false;
         }
         else
         {
            return true;
         }
      }