From 39785ddb0e6b3ef83ebf8aaa3e89be3c4005fa31 Mon Sep 17 00:00:00 2001
From: Kohei Takahashi <flast@flast.jp>
Date: Wed, 17 Oct 2012 18:05:39 +0900
Subject: [PATCH] Add convert implementation for Boost.Tuple

Signed-off-by: Kohei Takahashi <flast@flast.jp>
---
 include/boost/fusion/adapted/boost_tuple.hpp  |  1 +
 .../adapted/boost_tuple/detail/build_cons.hpp | 59 +++++++++++++++++++
 .../boost_tuple/detail/convert_impl.hpp       | 50 ++++++++++++++++
 3 files changed, 110 insertions(+)
 create mode 100644 include/boost/fusion/adapted/boost_tuple/detail/build_cons.hpp
 create mode 100644 include/boost/fusion/adapted/boost_tuple/detail/convert_impl.hpp

diff --git a/include/boost/fusion/adapted/boost_tuple.hpp b/include/boost/fusion/adapted/boost_tuple.hpp
index 85af5764..a391156d 100644
--- a/include/boost/fusion/adapted/boost_tuple.hpp
+++ b/include/boost/fusion/adapted/boost_tuple.hpp
@@ -17,5 +17,6 @@
 #include <boost/fusion/adapted/boost_tuple/detail/size_impl.hpp>
 #include <boost/fusion/adapted/boost_tuple/detail/at_impl.hpp>
 #include <boost/fusion/adapted/boost_tuple/detail/value_at_impl.hpp>
+#include <boost/fusion/adapted/boost_tuple/detail/convert_impl.hpp>
 
 #endif
diff --git a/include/boost/fusion/adapted/boost_tuple/detail/build_cons.hpp b/include/boost/fusion/adapted/boost_tuple/detail/build_cons.hpp
new file mode 100644
index 00000000..216fb0a6
--- /dev/null
+++ b/include/boost/fusion/adapted/boost_tuple/detail/build_cons.hpp
@@ -0,0 +1,59 @@
+/*=============================================================================
+    Copyright (c) 2012-2014 Kohei Takahashi
+
+    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_BUILD_CONS_10172012_0130)
+#define BOOST_FUSION_BUILD_CONS_10172012_0130
+
+#include <boost/tuple/tuple.hpp>
+#include <boost/fusion/iterator/equal_to.hpp>
+#include <boost/fusion/iterator/next.hpp>
+#include <boost/fusion/iterator/value_of.hpp>
+#include <boost/fusion/iterator/deref.hpp>
+
+namespace boost { namespace fusion { namespace detail
+{
+    template <
+        typename First
+      , typename Last
+      , bool is_empty = result_of::equal_to<First, Last>::value>
+    struct build_tuple_cons;
+
+    template <typename First, typename Last>
+    struct build_tuple_cons<First, Last, true>
+    {
+        typedef boost::tuples::null_type type;
+
+        BOOST_FUSION_GPU_ENABLED
+        static type
+        call(First const&, Last const&)
+        {
+            return type();
+        }
+    };
+
+    template <typename First, typename Last>
+    struct build_tuple_cons<First, Last, false>
+    {
+        typedef
+            build_tuple_cons<typename result_of::next<First>::type, Last>
+        next_build_tuple_cons;
+
+        typedef boost::tuples::cons<
+            typename result_of::value_of<First>::type
+          , typename next_build_tuple_cons::type>
+        type;
+
+        BOOST_FUSION_GPU_ENABLED
+        static type
+        call(First const& f, Last const& l)
+        {
+            typename result_of::value_of<First>::type v = *f;
+            return type(v, next_build_tuple_cons::call(fusion::next(f), l));
+        }
+    };
+}}}
+
+#endif
diff --git a/include/boost/fusion/adapted/boost_tuple/detail/convert_impl.hpp b/include/boost/fusion/adapted/boost_tuple/detail/convert_impl.hpp
new file mode 100644
index 00000000..8f2fbeec
--- /dev/null
+++ b/include/boost/fusion/adapted/boost_tuple/detail/convert_impl.hpp
@@ -0,0 +1,50 @@
+/*=============================================================================
+    Copyright (c) 2012-2014 Kohei Takahashi
+
+    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_CONVERT_IMPL_10172012_0120)
+#define BOOST_FUSION_CONVERT_IMPL_10172012_0120
+
+#include <boost/tuple/tuple.hpp>
+#include <boost/fusion/adapted/boost_tuple/detail/build_cons.hpp>
+#include <boost/fusion/sequence/intrinsic/begin.hpp>
+#include <boost/fusion/sequence/intrinsic/end.hpp>
+
+namespace boost { namespace fusion
+{
+    struct boost_tuple_tag;
+
+    namespace extension
+    {
+        template <typename T>
+        struct convert_impl;
+
+        template <>
+        struct convert_impl<boost_tuple_tag>
+        {
+            template <typename Sequence>
+            struct apply
+            {
+                typedef typename
+                    detail::build_tuple_cons<
+                        typename result_of::begin<Sequence>::type
+                      , typename result_of::end<Sequence>::type
+                    >
+                build_tuple_cons;
+
+                typedef typename build_tuple_cons::type type;
+
+                BOOST_FUSION_GPU_ENABLED
+                static type
+                call(Sequence& seq)
+                {
+                    return build_tuple_cons::call(fusion::begin(seq), fusion::end(seq));
+                }
+            };
+        };
+    }
+}}
+
+#endif