Added basic SoftwareRTC implementation.

See #3

Author: cmaglie

api/SoftwareRTC.cpp

@@ -0,0 +1,46 @@
+/*
+  Software RealTimeClock
+  Copyright (c) 2016 Arduino LLC. All right reserved.
+
+  This library 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 2.1 of the License, or (at your option) any later version.
+
+  This library 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 this library; if not, write to the Free Software
+  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+*/
+
+#include "Arduino.h"
+#include "SoftwareRTC.h"
+
+SoftwareRTC::SoftwareRTC() : lastTimestamp(0), lastMillis(0)
+{
+  // Empty
+}
+
+unsigned long SoftwareRTC::getTime()
+{
+  if (lastTimestamp == 0) return 0;
+  unsigned long now = millis();
+  unsigned long delta = now - lastMillis;
+  if (delta >= 1000) {
+    delta /= 1000; // Determine the number of seconds elapsed
+    lastMillis += delta * 1000;
+    lastTimestamp += delta;
+  }
+  return lastTimestamp;
+}
+
+bool SoftwareRTC::setTime(unsigned long t)
+{
+  lastTimestamp = t;
+  lastMillis = millis();
+}
+

api/SoftwareRTC.h

@@ -0,0 +1,41 @@
+/*
+  Software RealTimeClock
+  Copyright (c) 2016 Arduino LLC. All right reserved.
+
+  This library 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 2.1 of the License, or (at your option) any later version.
+
+  This library 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 this library; if not, write to the Free Software
+  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+*/
+
+#ifndef ARDUINO_SOFTWARE_RTC_H
+#define ARDUINO_SOFTWARE_RTC_H
+
+#include "RealTimeClock.h"
+
+class SoftwareRTC : public RealTimeClock {
+public:
+  SoftwareRTC();
+
+  // Get the current time as unix-timestamp.
+  // Return 0 if time has not been set.
+  virtual unsigned long getTime();
+
+  // Set the current time as unix-timestamp
+  virtual bool setTime(unsigned long t);
+
+private:
+  unsigned long lastTimestamp;
+  unsigned long lastMillis; 
+};
+
+#endif