Imported Upstream version 1.57.0upstream/1.57.0

1 files changed, 61 insertions, 0 deletions

diff --git a/boost/fusion/container/map/detail/at_key_impl.hpp b/boost/fusion/container/map/detail/at_key_impl.hpp
new file mode 100644
index 0000000000..5b57c4b835
--- /dev/null
+++ b/boost/fusion/container/map/detail/at_key_impl.hpp
@@ -0,0 +1,61 @@
+/*=============================================================================
+    Copyright (c) 2001-2013 Joel de Guzman
+
+    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)
+==============================================================================*/
+#if !defined(BOOST_FUSION_MAP_DETAIL_AT_KEY_IMPL_02042013_0821)
+#define BOOST_FUSION_MAP_DETAIL_AT_KEY_IMPL_02042013_0821
+
+#include <boost/fusion/support/config.hpp>
+#include <boost/fusion/support/detail/access.hpp>
+#include <boost/type_traits/is_const.hpp>
+#include <boost/mpl/at.hpp>
+#include <boost/mpl/identity.hpp>
+
+namespace boost { namespace fusion
+{
+    struct map_tag;
+
+    namespace extension
+    {
+        template <typename Tag>
+        struct at_key_impl;
+
+        template <>
+        struct at_key_impl<map_tag>
+        {
+            template <typename Sequence, typename Key>
+            struct apply
+            {
+                typedef
+                    decltype(std::declval<Sequence>().get(mpl::identity<Key>()))
+                type;
+
+                BOOST_FUSION_GPU_ENABLED
+                static type
+                call(Sequence& m)
+                {
+                    return m.get(mpl::identity<Key>());
+                }
+            };
+
+            template <typename Sequence, typename Key>
+            struct apply<Sequence const, Key>
+            {
+                typedef
+                    decltype(std::declval<Sequence const>().get(mpl::identity<Key>()))
+                type;
+
+                BOOST_FUSION_GPU_ENABLED
+                static type
+                call(Sequence const& m)
+                {
+                    return m.get(mpl::identity<Key>());
+                }
+            };
+        };
+    }
+}}
+
+#endif