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diff --git a/boost/python/cast.hpp b/boost/python/cast.hpp
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+++ b/boost/python/cast.hpp
@@ -0,0 +1,106 @@
+// Copyright David Abrahams 2002.
+// 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 CAST_DWA200269_HPP
+# define CAST_DWA200269_HPP
+
+# include <boost/python/detail/prefix.hpp>
+
+# include <boost/type_traits/same_traits.hpp>
+# include <boost/type_traits/cv_traits.hpp>
+# include <boost/type.hpp>
+# include <boost/python/base_type_traits.hpp>
+# include <boost/python/detail/convertible.hpp>
+
+namespace boost { namespace python { 
+
+namespace detail
+{
+  template <class Source, class Target> inline Target* upcast_impl(Source*, Target*);
+  
+  template <class Source, class Target>
+  inline Target* upcast(Source* p, yes_convertible, no_convertible, Target*)
+  {
+      return p;
+  }
+
+  template <class Source, class Target>
+  inline Target* upcast(Source* p, no_convertible, no_convertible, Target*)
+  {
+      typedef typename base_type_traits<Source>::type base;
+      
+      return detail::upcast_impl((base*)p, (Target*)0);
+  }
+
+  template <bool is_same = true>
+  struct upcaster
+  {
+      template <class T>
+      static inline T* execute(T* x, T*) { return x; }
+  };
+  
+  template <>
+  struct upcaster<false>
+  {
+      template <class Source, class Target>
+      static inline Target* execute(Source* x, Target*)
+      {
+          return detail::upcast(
+              x, detail::convertible<Target*>::check(x)
+              , detail::convertible<Source*>::check((Target*)0)
+              , (Target*)0);
+      }
+  };
+
+
+  template <class Target, class Source>
+  inline Target* downcast(Source* p, yes_convertible)
+  {
+      return static_cast<Target*>(p);
+  }
+
+  template <class Target, class Source>
+  inline Target* downcast(Source* p, no_convertible, boost::type<Target>* = 0)
+  {
+      typedef typename base_type_traits<Source>::type base;
+      return (Target*)detail::downcast<base>(p, convertible<Source*>::check((base*)0));
+  }
+
+  template <class T>
+  inline void assert_castable(boost::type<T>* = 0)
+  {
+      typedef char must_be_a_complete_type[sizeof(T)];
+  }
+
+  template <class Source, class Target>
+  inline Target* upcast_impl(Source* x, Target*)
+  {
+      typedef typename add_cv<Source>::type src_t;
+      typedef typename add_cv<Target>::type target_t;
+      bool const same = is_same<src_t,target_t>::value;
+      
+      return detail::upcaster<same>::execute(x, (Target*)0);
+  }
+}
+
+template <class Target, class Source>
+inline Target* upcast(Source* x, Target* = 0)
+{
+    detail::assert_castable<Source>();
+    detail::assert_castable<Target>();
+    return detail::upcast_impl(x, (Target*)0);
+    
+}
+
+template <class Target, class Source>
+inline Target* downcast(Source* x, Target* = 0)
+{
+    detail::assert_castable<Source>();
+    detail::assert_castable<Target>();
+    return detail::downcast<Target>(x, detail::convertible<Source*>::check((Target*)0));
+}
+
+}} // namespace boost::python
+
+#endif // CAST_DWA200269_HPP