Incomplete work for using Boost.Polygon to compute medial axis

xs/src/boost/concept/usage.hpp

@@ -0,0 +1,44 @@
+// Copyright David Abrahams 2006. Distributed under the Boost
+// Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+#ifndef BOOST_CONCEPT_USAGE_DWA2006919_HPP
+# define BOOST_CONCEPT_USAGE_DWA2006919_HPP
+
+# include <boost/concept/assert.hpp>
+# include <boost/detail/workaround.hpp>
+# include <boost/concept/detail/backward_compatibility.hpp>
+
+namespace boost { namespace concepts { 
+
+# if BOOST_WORKAROUND(__GNUC__, == 2)
+
+#  define BOOST_CONCEPT_USAGE(model) ~model()
+
+# else 
+
+template <class Model>
+struct usage_requirements
+{
+    ~usage_requirements() { ((Model*)0)->~Model(); }
+};
+
+#  if BOOST_WORKAROUND(__GNUC__, <= 3)
+
+#   define BOOST_CONCEPT_USAGE(model)                                    \
+      model(); /* at least 2.96 and 3.4.3 both need this :( */           \
+      BOOST_CONCEPT_ASSERT((boost::concepts::usage_requirements<model>)); \
+      ~model()
+
+#  else
+
+#   define BOOST_CONCEPT_USAGE(model)                                    \
+      BOOST_CONCEPT_ASSERT((boost::concepts::usage_requirements<model>)); \
+      ~model()
+
+#  endif
+
+# endif 
+
+}} // namespace boost::concepts
+
+#endif // BOOST_CONCEPT_USAGE_DWA2006919_HPP