public void Write(HJ212Message message)
{
_streamResource.DiscardInBuffer();
byte[] frame = BuildMessageFrame(message);
_streamResource.Write(frame, 0, frame.Length);
}
internal bool ChecksumsMatch(HJ212Message message, byte[] messageFrame)
{
var crcString = Encoding.ASCII.GetString(messageFrame, messageFrame.Length - 4, 4);
var crcBytes = BytesUtility.HexToBytes(crcString);
return(BitConverter.ToUInt16(crcBytes, 0) ==
BitConverter.ToUInt16(BytesUtility.CalculateCrc(message.MessageFrame), 0));
}
public T UnicastMessage <T>(HJ212Message message) where T : HJ212Message, new()
{
HJ212Message response = null;
lock (_syncLock)
{
Write(message);
response = ReadResponse <T>();
}
ValidateResponse(message, response);
return((T)response);
}
internal byte[] BuildMessageFrame(HJ212Message message)
{
var messageFrame = message.MessageFrame;
var crc = BytesUtility.GetAsciiBytes(BytesUtility.CalculateCrc(messageFrame));
var messageBody = new MemoryStream(_header.Length + _len.Length +
messageFrame.Length + crc.Length + _tailer.Length);
messageBody.Write(Encoding.ASCII.GetBytes(_header), 0, _header.Length);
messageBody.Write(Encoding.ASCII.GetBytes(_len), 0, _header.Length);
messageBody.Write(messageFrame, 0, messageFrame.Length);
messageBody.Write(crc, 0, crc.Length);
messageBody.Write(Encoding.ASCII.GetBytes(_tailer), 0, _tailer.Length);
return(messageBody.ToArray());
}
internal void ValidateResponse(HJ212Message request, HJ212Message response)
{
// always check the function code and slave address, regardless of transport protocol
if (request.QN != request.QN)
{
throw new IOException(String.Format(CultureInfo.InvariantCulture,
"Received response with unexpected QN. Expected {0}, received {1}.", request.QN,
response.QN));
}
if (request.MN != response.MN)
{
throw new IOException(String.Format(CultureInfo.InvariantCulture,
"Response MN does not match request. Expected {0}, received {1}.", response.MN,
request.MN));
}
// message specific validation
if (request != null)
{
request.ValidateResponse(response);
}
}
