diff --git a/src/abstractreader.cpp b/src/abstractreader.cpp
--- a/src/abstractreader.cpp
+++ b/src/abstractreader.cpp
@@ -1,5 +1,5 @@
 /*
-  Copyright © 2018 Hasan Yavuz Özderya
+  Copyright © 2019 Hasan Yavuz Özderya
 
   This file is part of serialplot.
 
@@ -23,6 +23,7 @@ AbstractReader::AbstractReader(QIODevice
     QObject(parent)
 {
     _device = device;
+    bytesRead = 0;
 }
 
 void AbstractReader::pause(bool enabled)
@@ -43,3 +44,15 @@ void AbstractReader::enable(bool enabled
         disconnectSinks();
     }
 }
+
+void AbstractReader::onDataReady()
+{
+    bytesRead += readData();
+}
+
+unsigned AbstractReader::getBytesRead()
+{
+    unsigned r = bytesRead;
+    bytesRead = 0;
+    return r;
+}