Rework of Plugin _P056_SDS011-Dust (#451)

* First rework

* Moved classes to library

* Finished rework

lib/SerialDevices/SensorSerialBuffer.cpp

@@ -0,0 +1,59 @@
+/*-------------------------------------------------------------------------
+  Arduino library to ...
+
+  Written by Jochen Krapf,
+  contributions by ... and other members of the open
+  source community.
+
+  -------------------------------------------------------------------------
+  This file is part of the MechInputs library.
+
+  MechInputs is free software: you can redistribute it and/or modify
+  it under the terms of the GNU Lesser General Public License as
+  published by the Free Software Foundation, either version 3 of
+  the License, or (at your option) any later version.
+
+  MechInputs is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public
+  License along with MechInputs.  If not, see
+  <http://www.gnu.org/licenses/>.
+  -------------------------------------------------------------------------*/
+
+#include "SensorSerialBuffer.h"
+
+CSensorSerialBuffer::CSensorSerialBuffer()
+{
+  _writeIndex = 0;
+  _packetLength = 0;
+  Clear();
+}
+
+void CSensorSerialBuffer::Clear ()
+{
+  for (byte i=0; i<SERIALBUFFER_SIZE; i++)
+    _buffer[i] = 0;
+}
+
+void CSensorSerialBuffer::AddData (byte b)
+{
+  _buffer[_writeIndex] = b;
+  _writeIndex++;
+  _writeIndex &= SERIALBUFFER_MASK;
+}
+
+void CSensorSerialBuffer::SetPacketLength (byte len)
+{
+  _packetLength = len;
+}
+
+byte& CSensorSerialBuffer::operator[] (byte x)
+{
+  x += _writeIndex;
+  x -= _packetLength;
+  x &= SERIALBUFFER_MASK;
+  return _buffer[x];
+}