Imported Upstream version 1.57.0upstream/1.57.0

1 files changed, 126 insertions, 0 deletions

diff --git a/boost/type_erasure/detail/extract_concept.hpp b/boost/type_erasure/detail/extract_concept.hpp
new file mode 100644
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+++ b/boost/type_erasure/detail/extract_concept.hpp
@@ -0,0 +1,126 @@
+// Boost.TypeErasure library
+//
+// Copyright 2011 Steven Watanabe
+//
+// 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)
+//
+// $Id$
+
+#if !defined(BOOST_PP_IS_ITERATING)
+
+#ifndef BOOST_TYPE_ERASURE_DETAIL_EXTRACT_CONCEPT_HPP_INCLUDED
+#define BOOST_TYPE_ERASURE_DETAIL_EXTRACT_CONCEPT_HPP_INCLUDED
+
+#include <boost/mpl/eval_if.hpp>
+#include <boost/mpl/identity.hpp>
+#include <boost/type_traits/remove_cv.hpp>
+#include <boost/type_traits/remove_reference.hpp>
+#include <boost/preprocessor/cat.hpp>
+#include <boost/preprocessor/inc.hpp>
+#include <boost/preprocessor/iteration/iterate.hpp>
+#include <boost/preprocessor/repetition/repeat.hpp>
+#include <boost/preprocessor/repetition/enum_params.hpp>
+#include <boost/type_erasure/is_placeholder.hpp>
+#include <boost/type_erasure/concept_of.hpp>
+#include <boost/type_erasure/config.hpp>
+
+namespace boost {
+namespace type_erasure {
+namespace detail {
+
+template<class T, class U>
+struct combine_concepts;
+
+template<class T>
+struct combine_concepts<T, T> { typedef T type; };
+template<class T>
+struct combine_concepts<T, void> { typedef T type; };
+template<class T>
+struct combine_concepts<void, T> { typedef T type; };
+template<>
+struct combine_concepts<void, void> { typedef void type; };
+
+template<class T, class U>
+struct maybe_extract_concept
+{
+    typedef typename ::boost::mpl::eval_if<
+        ::boost::type_erasure::is_placeholder<
+            typename ::boost::remove_cv<
+                typename ::boost::remove_reference<T>::type
+            >::type
+        >,
+        ::boost::type_erasure::concept_of<typename ::boost::remove_reference<U>::type>,
+        ::boost::mpl::identity<void>
+    >::type type;
+};
+
+#if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
+
+template<class Args, class... U>
+struct extract_concept;
+
+template<class R, class T0, class... T, class U0, class... U>
+struct extract_concept<R(T0, T...), U0, U...>
+{
+    typedef typename ::boost::type_erasure::detail::combine_concepts<
+        typename ::boost::type_erasure::detail::maybe_extract_concept<
+            T0, U0
+        >::type,
+        typename ::boost::type_erasure::detail::extract_concept<
+            void(T...),
+            U...
+        >::type
+    >::type type;
+};
+
+template<>
+struct extract_concept<void()>
+{
+    typedef void type;
+};
+
+#else
+//#endif
+
+#define BOOST_PP_FILENAME_1 <boost/type_erasure/detail/extract_concept.hpp>
+#define BOOST_PP_ITERATION_LIMITS (1, BOOST_TYPE_ERASURE_MAX_ARITY)
+#include BOOST_PP_ITERATE()
+
+#endif
+
+}
+}
+}
+
+#endif
+
+#else
+
+#define N BOOST_PP_ITERATION()
+
+#define BOOST_TYPE_ERASURE_EXTRACT_CONCEPT(z, n, data)                  \
+    typedef typename ::boost::type_erasure::detail::combine_concepts<   \
+        typename ::boost::type_erasure::detail::maybe_extract_concept<  \
+            BOOST_PP_CAT(T, n), BOOST_PP_CAT(U, n)                      \
+        >::type,                                                        \
+        BOOST_PP_CAT(concept, n)                                        \
+    >::type BOOST_PP_CAT(concept, BOOST_PP_INC(n));
+
+template<
+    BOOST_PP_ENUM_PARAMS(N, class T),
+    BOOST_PP_ENUM_PARAMS(N, class U)>
+struct BOOST_PP_CAT(extract_concept, N)
+{
+    typedef void concept0;
+
+    BOOST_PP_REPEAT(N, BOOST_TYPE_ERASURE_EXTRACT_CONCEPT, ~)
+
+    typedef BOOST_PP_CAT(concept, N) type;
+};
+
+#undef BOOST_TYPE_ERASURE_EXTRACT_CONCEPT
+#undef N
+
+#endif