private void Read(ModbusDevice device, ModbusFunctionCode functionCode, int zeroBasedOffset, int count, Action <MessageBufferSpan> actionWithReturnedBuffer)
{
var requestContext = new ModbusTransportContext()
{
TransactionIdentifier = GetTransactionIdentifier()
};
ModbusTransport.SendMessage(requestContext,
(writer) =>
{
writer.Push(device.Address);
writer.Push((byte)functionCode);
writer.Push((byte)((zeroBasedOffset >> 8) & 0xFF));
writer.Push((byte)((zeroBasedOffset >> 0) & 0xFF));
writer.Push((byte)((count >> 8) & 0xFF));
writer.Push((byte)((count >> 0) & 0xFF));
});
MessageBufferSpan?receivedBuffer = null;
var responseContext = ModbusTransport.ReceiveMessage(
(reader) =>
{
if (reader.PushByteFromStream() != device.Address)
{
throw new InvalidOperationException();
}
byte receivedFunctionCode = reader.PushByteFromStream();
if (receivedFunctionCode == ((byte)functionCode | 0x80))
{
var exceptionCode = (ModbusExceptionCode)reader.PushByteFromStream();
throw new ModbusException(exceptionCode);
}
if (receivedFunctionCode != (byte)functionCode)
{
throw new InvalidOperationException();
}
var byteCount = reader.PushByteFromStream();
reader.PushFromStream(byteCount);
receivedBuffer = new MessageBufferSpan(reader.Buffer, (ushort)(reader.Buffer.Length - byteCount), byteCount);
});
if (responseContext.TransactionIdentifier != requestContext.TransactionIdentifier)
{
throw new InvalidOperationException();
}
actionWithReturnedBuffer(receivedBuffer !);
}
private T Write <T>(ModbusDevice device, ModbusFunctionCode functionCode, int zeroBasedOffset, Action <IMessageBufferWriter> writeAction, Func <IMessageBufferReader, T> readValueFunc)
{
var requestContext = new ModbusTransportContext()
{
TransactionIdentifier = GetTransactionIdentifier()
};
ModbusTransport.SendMessage(requestContext,
(writer) =>
{
writer.Push(device.Address);
writer.Push((byte)functionCode);
writer.Push((byte)((zeroBasedOffset >> 8) & 0xFF));
writer.Push((byte)((zeroBasedOffset >> 0) & 0xFF));
writeAction(writer);
});
T returnedValue = default;
var responseContext = ModbusTransport.ReceiveMessage(
(reader) =>
{
if (reader.PushByteFromStream() != device.Address)
{
throw new InvalidOperationException();
}
byte receivedFunctionCode = reader.PushByteFromStream();
if (receivedFunctionCode == ((byte)functionCode | 0x80))
{
var exceptionCode = (ModbusExceptionCode)reader.PushByteFromStream();
throw new ModbusException(exceptionCode);
}
if (receivedFunctionCode != (byte)functionCode)
{
throw new InvalidOperationException();
}
if ((ushort)((reader.PushByteFromStream() << 8) + (reader.PushByteFromStream() << 0)) != zeroBasedOffset)
{
throw new InvalidOperationException();
}
returnedValue = readValueFunc(reader);
});
if (requestContext.TransactionIdentifier != responseContext.TransactionIdentifier)
{
throw new InvalidOperationException();
}
return(returnedValue !);
}