Added boost header

test/external/boost/python/object/forward.hpp

@@ -0,0 +1,194 @@
+// Copyright David Abrahams 2001.
+// 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 FORWARD_DWA20011215_HPP
+# define FORWARD_DWA20011215_HPP
+
+# include <boost/mpl/if.hpp>
+# include <boost/type_traits/is_scalar.hpp>
+# include <boost/type_traits/add_const.hpp>
+# include <boost/type_traits/add_reference.hpp>
+# include <boost/ref.hpp>
+# include <boost/python/detail/value_arg.hpp>
+# include <boost/python/detail/copy_ctor_mutates_rhs.hpp>
+# if BOOST_WORKAROUND(BOOST_MSVC, < 1300)
+#  include <boost/type_traits/is_enum.hpp>
+#  include <boost/mpl/and.hpp>
+#  include <boost/mpl/not.hpp>
+# else
+#  include <boost/mpl/or.hpp>
+# endif 
+
+namespace boost { namespace python { namespace objects { 
+
+// Very much like boost::reference_wrapper<T>, except that in this
+// case T can be a reference already without causing a
+// reference-to-reference error.
+template <class T>
+struct reference_to_value
+{
+    typedef typename add_reference<typename add_const<T>::type>::type reference;
+    
+    reference_to_value(reference x) : m_value(x) {}
+    reference get() const { return m_value; }
+ private:
+    reference m_value;
+};
+
+// A little metaprogram which selects the type to pass through an
+// intermediate forwarding function when the destination argument type
+// is T.
+template <class T>
+struct forward
+    : mpl::if_<
+# if BOOST_WORKAROUND(BOOST_MSVC, < 1300)
+          // vc6 chokes on unforwarding enums nested in classes
+          mpl::and_<
+              is_scalar<T>
+            , mpl::not_< 
+                  is_enum<T>
+              >
+          >
+# else 
+          mpl::or_<python::detail::copy_ctor_mutates_rhs<T>, is_scalar<T> >
+# endif 
+        , T
+        , reference_to_value<T>
+      >
+{
+};
+
+# ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
+template<typename T>
+struct unforward
+{
+    typedef typename unwrap_reference<T>::type& type;
+};
+
+template<typename T>
+struct unforward<reference_to_value<T> >
+{
+    typedef T type;
+};
+
+template <typename T>
+struct unforward_cref
+  : python::detail::value_arg<
+        typename unwrap_reference<T>::type
+    >
+{
+};
+
+template<typename T>
+struct unforward_cref<reference_to_value<T> >
+  : add_reference<typename add_const<T>::type>
+{
+};
+
+# else // no partial specialization
+
+namespace detail
+{
+  typedef char (&yes_reference_to_value_t)[1];
+  typedef char (&no_reference_to_value_t)[2];
+      
+  no_reference_to_value_t is_reference_to_value_test(...);
+
+  template<typename T>
+  yes_reference_to_value_t is_reference_to_value_test(boost::type< reference_to_value<T> >);
+
+  template<bool wrapped>
+  struct unforwarder
+  {
+      template <class T>
+      struct apply
+      {
+          typedef typename unwrap_reference<T>::type& type;
+      };
+  };
+
+  template<>
+  struct unforwarder<true>
+  {
+      template <class T>
+      struct apply
+      {
+          typedef typename T::reference type;
+      };
+  };
+
+  template<bool wrapped = false>
+  struct cref_unforwarder
+  {
+      template <class T>
+      struct apply
+        : python::detail::value_arg<
+              typename unwrap_reference<T>::type
+          >
+      {          
+      };
+  };
+      
+  template<>
+  struct cref_unforwarder<true>
+  {
+      template <class T>
+      struct apply
+        : python::detail::value_arg<
+              typename T::reference
+          >
+      {
+      };
+  };
+
+  template<typename T>
+  struct is_reference_to_value
+  {
+      BOOST_STATIC_CONSTANT(
+          bool, value = (
+              sizeof(is_reference_to_value_test(boost::type<T>()))
+              == sizeof(yes_reference_to_value_t)));
+      typedef mpl::bool_<value> type;
+  };
+}
+
+template <typename T>
+struct unforward
+    : public detail::unforwarder<
+        detail::is_reference_to_value<T>::value
+      >::template apply<T>
+{};
+
+template <typename T>
+struct unforward_cref
+    : public detail::cref_unforwarder<
+        detail::is_reference_to_value<T>::value
+      >::template apply<T>
+{};
+
+# endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
+
+template <class T>
+typename reference_to_value<T>::reference
+do_unforward(reference_to_value<T> const& x, int)
+{
+    return x.get();
+}
+
+template <class T>
+typename reference_wrapper<T>::type&
+do_unforward(reference_wrapper<T> const& x, int)
+{
+    return x.get();
+}
+
+template <class T>
+T const& do_unforward(T const& x, ...)
+{
+    return x;
+}
+
+}}} // namespace boost::python::objects
+
+#endif // FORWARD_DWA20011215_HPP