diff --git a/src/linindexbuffer.cpp b/src/linindexbuffer.cpp
new file mode 100644
--- /dev/null
+++ b/src/linindexbuffer.cpp
@@ -0,0 +1,57 @@
+ /*
+  Copyright © 2017 Hasan Yavuz Özderya
+
+  This file is part of serialplot.
+
+  serialplot is free software: you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  serialplot 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 General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with serialplot.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <QtGlobal>
+
+#include "linindexbuffer.h"
+
+LinIndexBuffer::LinIndexBuffer(unsigned n, Range lim)
+{
+    Q_ASSERT(n > 0);
+
+    _size = n;
+    setLimits(lim);
+}
+
+unsigned LinIndexBuffer::size() const
+{
+    return _size;
+}
+
+double LinIndexBuffer::sample(unsigned i) const
+{
+    return _limits.start + i * _step;
+}
+
+Range LinIndexBuffer::limits() const
+{
+    return _limits;
+}
+
+void LinIndexBuffer::resize(unsigned n)
+{
+    _size = n;
+    setLimits(_limits);         // called to update `_step`
+}
+
+void LinIndexBuffer::setLimits(Range lim)
+{
+    _limits = lim;
+    _step = (lim.end - lim.start) / (_size-1);
+}