diff --git a/src/readonlybuffer.h b/src/readonlybuffer.h
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+/*
+  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/>.
+*/
+
+#ifndef READONLYBUFFER_H
+#define READONLYBUFFER_H
+
+// IMPORTANT TODO: rename to "framebuffer.h" when stream work is done.
+#include "framebuffer2.h"
+
+/// A read only frame buffer used for storing snapshot data. Main advantage of
+/// this compared to `RingBuffer` is that reading data should be somewhat
+/// faster.
+class ReadOnlyBuffer : public FrameBuffer
+{
+public:
+    /// Creates a buffer with data copied from `source`. Source buffer cannot be
+    /// empty.
+    ReadOnlyBuffer(const FrameBuffer* source);
+
+    /// Creates a buffer from a slice of the `source`.
+    ///
+    /// @param start start of the slice
+    /// @param n number of samples
+    ///
+    /// @important (start + n) should be smaller or equal than `source->size()`,
+    /// otherwise it's an error.
+    ReadOnlyBuffer(const FrameBuffer* source, unsigned start, unsigned n);
+
+    ~ReadOnlyBuffer();
+
+    virtual unsigned size() const;
+    virtual double sample(unsigned i) const;
+    virtual Range limits() const;
+
+private:
+    double* data;    ///< data storage
+    unsigned _size;  ///< data size
+    Range _limits;   ///< limits cache
+};
+
+#endif // READONLYBUFFER_H