diff -r c595cfb4791c -r 31540c1f22ea src/misc/ringFinder.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/misc/ringFinder.h	Mon Jan 20 15:04:26 2014 +0200
@@ -0,0 +1,88 @@
+/*
+ *  LDForge: LDraw parts authoring CAD
+ *  Copyright (C) 2013, 2014 Santeri Piippo
+ *
+ *  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 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef LDFORGE_MISC_RINGFINDER_H
+#define LDFORGE_MISC_RINGFINDER_H
+
+#include "../main.h"
+
+// =============================================================================
+// RingFinder
+//
+// Provides an algorithm for finding a solution of rings between radii r0 and r1.
+// =============================================================================
+class RingFinder
+{
+	public:
+		struct Component
+		{
+			int num;
+			double scale;
+		};
+
+		class Solution
+		{
+			public:
+				// Components of this solution
+				inline const QVector<Component>& getComponents() const
+				{
+					return m_components;
+				}
+
+				// Add a component to this solution
+				inline void addComponent (const Component& a)
+				{
+					m_components.push_back (a);
+				}
+
+				// Compare solutions
+				bool isBetterThan (const Solution* other) const;
+
+			private:
+				QVector<Component> m_components;
+		};
+
+		RingFinder() {}
+		bool findRings (double r0, double r1);
+
+		inline const Solution* bestSolution()
+		{
+			return m_bestSolution;
+		}
+
+		inline const QVector<Solution>& allSolutions() const
+		{
+			return m_solutions;
+		}
+
+		inline bool operator() (double r0, double r1)
+		{
+			return findRings (r0, r1);
+		}
+
+	private:
+		QVector<Solution> m_solutions;
+		const Solution*   m_bestSolution;
+		int               m_stack;
+
+		bool findRingsRecursor (double r0, double r1, Solution& currentSolution);
+};
+
+extern RingFinder g_RingFinder;
+
+#endif // LDFORGE_MISC_RINGFINDER_H
\ No newline at end of file