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+
+/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*- vi:set ts=8 sts=4 sw=4: */
+
+/*
+    Rosegarden
+    A MIDI and audio sequencer and musical notation editor.
+
+    This program is Copyright 2000-2008
+        Guillaume Laurent   <glaurent@telegraph-road.org>,
+        Chris Cannam        <cannam@all-day-breakfast.com>,
+        Richard Bown        <richard.bown@ferventsoftware.com>
+
+    The moral rights of Guillaume Laurent, Chris Cannam, and Richard
+    Bown to claim authorship of this work have been asserted.
+
+    Other copyrights also apply to some parts of this work.  Please
+    see the AUTHORS file and individual file headers for details.
+
+    This program 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 2 of the
+    License, or (at your option) any later version.  See the file
+    COPYING included with this distribution for more information.
+*/
+
+#ifndef _RG_BASICCOMMAND_H_
+#define _RG_BASICCOMMAND_H_
+
+#include "base/Segment.h"
+#include <kcommand.h>
+#include "base/Event.h"
+#include "misc/Debug.h"
+
+class QString;
+
+
+namespace Rosegarden
+{
+
+
+
+/**
+ * BasicCommand is an abstract subclass of Command that manages undo,
+ * redo and notification of changes within a contiguous region of a
+ * single Rosegarden Segment, by brute force.  When a subclass
+ * of BasicCommand executes, it stores a copy of the events that are
+ * modified by the command, ready to be restored verbatim on undo.
+ */
+
+class BasicCommand : public KNamedCommand
+{
+public:
+    virtual ~BasicCommand();
+
+    virtual void execute();
+    virtual void unexecute();
+
+    virtual Segment &getSegment();
+
+    timeT getStartTime() { return m_startTime; }
+    timeT getEndTime() { return m_endTime; }
+    virtual timeT getRelayoutEndTime();
+
+protected:
+    /**
+     * You should pass "bruteForceRedoRequired = true" if your
+     * subclass's implementation of modifySegment uses discrete
+     * event pointers or segment iterators to determine which
+     * events to modify, in which case it won't work when
+     * replayed for redo because the pointers may no longer be
+     * valid.  In which case, BasicCommand will implement redo
+     * much like undo, and will only call your modifySegment 
+     * the very first time the command object is executed.
+     *
+     * It is always safe to pass bruteForceRedoRequired true,
+     * it's just normally a waste of memory.
+     */
+    BasicCommand(const QString &name,
+                 Segment &segment,
+                 timeT start, timeT end,
+                 bool bruteForceRedoRequired = false);
+
+    virtual void modifySegment() = 0;
+
+    virtual void beginExecute();
+
+private:
+    //--------------- Data members ---------------------------------
+
+    void copyTo(Segment *);
+    void copyFrom(Segment *);
+
+    timeT calculateStartTime(timeT given,
+                                         Segment &segment);
+    timeT calculateEndTime(timeT given,
+                                       Segment &segment);
+
+    timeT m_startTime;
+    timeT m_endTime;
+
+    Segment &m_segment;
+    Segment m_savedEvents;
+
+    bool m_doBruteForceRedo;
+    Segment *m_redoEvents;
+};
+
+
+
+}
+
+#endif