Updated boost to v1.55.0

[rsem.git] / boost / fusion / container / list / detail / at_impl.hpp

diff --git a/boost/fusion/container/list/detail/at_impl.hpp b/boost/fusion/container/list/detail/at_impl.hpp
new file mode 100644 (file)
index 0000000..7574639
--- /dev/null
+++ b/boost/fusion/container/list/detail/at_impl.hpp
@@ -0,0 +1,132 @@
+/*=============================================================================
+    Copyright (c) 2001-2011 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(FUSION_AT_IMPL_07172005_0726)
+#define FUSION_AT_IMPL_07172005_0726
+
+#include <boost/fusion/support/detail/access.hpp>
+#include <boost/type_traits/is_const.hpp>
+#include <boost/type_traits/add_const.hpp>
+#include <boost/mpl/if.hpp>
+#include <boost/mpl/bool.hpp>
+
+namespace boost { namespace fusion
+{
+    namespace detail
+    {
+        template <typename Cons>
+        struct cons_deref
+        {
+            typedef typename Cons::car_type type;
+        };
+
+        template <typename Cons, int I>
+        struct cons_advance
+        {
+            typedef typename
+                cons_advance<Cons, I-1>::type::cdr_type
+            type;
+        };
+
+        template <typename Cons>
+        struct cons_advance<Cons, 0>
+        {
+            typedef Cons type;
+        };
+
+        template <typename Cons>
+        struct cons_advance<Cons, 1>
+        {
+            typedef typename Cons::cdr_type type;
+        };
+
+        template <typename Cons>
+        struct cons_advance<Cons, 2>
+        {
+#if BOOST_WORKAROUND(BOOST_MSVC, > 1400) // VC8 and above
+            typedef typename Cons::cdr_type::cdr_type type;
+#else
+            typedef typename Cons::cdr_type _a;
+            typedef typename _a::cdr_type type;
+#endif
+        };
+
+        template <typename Cons>
+        struct cons_advance<Cons, 3>
+        {
+#if BOOST_WORKAROUND(BOOST_MSVC, > 1400) // VC8 and above
+            typedef typename Cons::cdr_type::cdr_type::cdr_type type;
+#else
+            typedef typename Cons::cdr_type _a;
+            typedef typename _a::cdr_type _b;
+            typedef typename _b::cdr_type type;
+#endif
+        };
+
+        template <typename Cons>
+        struct cons_advance<Cons, 4>
+        {
+#if BOOST_WORKAROUND(BOOST_MSVC, > 1400) // VC8 and above
+            typedef typename Cons::cdr_type::cdr_type::cdr_type::cdr_type type;
+#else
+            typedef typename Cons::cdr_type _a;
+            typedef typename _a::cdr_type _b;
+            typedef typename _b::cdr_type _c;
+            typedef typename _c::cdr_type type;
+#endif
+        };
+    }
+
+    struct cons_tag;
+
+    namespace extension
+    {
+        template <typename Tag>
+        struct at_impl;
+
+        template <>
+        struct at_impl<cons_tag>
+        {
+            template <typename Sequence, typename N>
+            struct apply
+            {
+                typedef typename detail::cons_deref<
+                    typename detail::cons_advance<Sequence, N::value>::type>::type
+                element;
+
+                typedef typename
+                    mpl::if_<
+                        is_const<Sequence>
+                      , typename detail::cref_result<element>::type
+                      , typename detail::ref_result<element>::type
+                    >::type
+                type;
+
+                template <typename Cons, int N2>
+                static type
+                call(Cons& s, mpl::int_<N2>)
+                {
+                    return call(s.cdr, mpl::int_<N2-1>());
+                }
+
+                template <typename Cons>
+                static type
+                call(Cons& s, mpl::int_<0>)
+                {
+                    return s.car;
+                }
+
+                static type
+                call(Sequence& s)
+                {
+                    return call(s, mpl::int_<N::value>());
+                }
+            };
+        };
+    }
+}}
+
+#endif