Imported existing code

libraries/include/boost/python/detail/is_wrapper.hpp

@@ -0,0 +1,29 @@
+// Copyright David Abrahams 2004. 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 IS_WRAPPER_DWA2004723_HPP
+# define IS_WRAPPER_DWA2004723_HPP
+
+# include <boost/python/detail/prefix.hpp>
+# include <boost/mpl/bool.hpp>
+
+namespace boost { namespace python {
+
+template <class T> class wrapper;
+
+namespace detail
+{
+  typedef char (&is_not_wrapper)[2];
+  is_not_wrapper is_wrapper_helper(...);
+  template <class T>
+  char is_wrapper_helper(wrapper<T> const volatile*);
+
+  // A metafunction returning true iff T is [derived from] wrapper<U> 
+  template <class T>
+  struct is_wrapper
+    : mpl::bool_<(sizeof(detail::is_wrapper_helper((T*)0)) == 1)>
+  {};
+
+}}} // namespace boost::python::detail
+
+#endif // IS_WRAPPER_DWA2004723_HPP