void IProtocolCodec.ServerEncode(CommDataBase data)
{
var server = (ModbusServer)data.OwnerProtocol;
var command = (ModbusCommand)data.UserData;
var fncode = command.FunctionCode;
//encode the command body, if applies
var body = new ByteArrayWriter();
var codec = CommandCodecs[fncode];
if (codec != null)
{
codec.ServerEncode(command, body);
}
//calculate length field
var length = (command.ExceptionCode == 0)
? 2 + body.Length
: 3;
//create a writer for the outgoing data
var writer = new ByteArrayWriter();
//unit identifier (address)
writer.WriteByte(server.Address);
if (command.ExceptionCode == 0)
{
//function code
writer.WriteByte(fncode);
//body data
writer.WriteBytes(body);
}
else
{
//function code
writer.WriteByte((byte)(command.FunctionCode | 0x80));
//exception code
writer.WriteByte(command.ExceptionCode);
}
//CRC-16
ushort crc;
unchecked
{
crc = (ushort)ModbusRtuCodec.Crc16.Compute(
((IByteArray)writer).Data,
0,
writer.Length);
}
writer.WriteUInt16LE(crc);
data.OutgoingData = writer.ToReader();
}
void IProtocolCodec.ClientEncode(CommDataBase data)
{
var client = (ModbusClient)data.OwnerProtocol;
var command = (ModbusCommand)data.UserData;
var fncode = command.FunctionCode;
//encode the command body, if applies
var body = new ByteArrayWriter();
var codec = CommandCodecs[fncode];
if (codec != null)
{
codec.ClientEncode(command, body);
}
//create a writer for the outgoing data
var writer = new ByteArrayWriter();
//unit identifier (address)
writer.WriteByte(client.Address);
//function code
writer.WriteByte(fncode);
//body data
writer.WriteBytes(body);
//CRC-16
ushort crc;
unchecked
{
crc = (ushort)ModbusRtuCodec.Crc16.Compute(
((IByteArray)writer).Data,
0,
writer.Length
);
}
writer.WriteUInt16LE(crc);
data.OutgoingData = writer.ToReader();
}