branch for creating branch for fusion 2.1

[SVN r40237]

include/boost/fusion/iterator/equal_to.hpp

@@ -0,0 +1,93 @@
+/*=============================================================================
+    Copyright (c) 2001-2006 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_EQUAL_TO_05052005_1208)
+#define FUSION_EQUAL_TO_05052005_1208
+
+#include <boost/type_traits/is_same.hpp>
+#include <boost/fusion/support/tag_of.hpp>
+#include <boost/type_traits/add_const.hpp>
+#include <boost/fusion/support/is_iterator.hpp>
+#include <boost/mpl/and.hpp>
+#include <boost/utility/enable_if.hpp>
+
+namespace boost { namespace fusion
+{
+    // Special tags:
+    struct iterator_facade_tag; // iterator facade tag
+    struct array_iterator_tag; // boost::array iterator tag
+    struct mpl_iterator_tag; // mpl sequence iterator tag
+    struct std_pair_iterator_tag; // std::pair iterator tag
+
+    namespace extension
+    {
+        template <typename Tag>
+        struct equal_to_impl
+        {
+            // default implementation
+            template <typename I1, typename I2>
+            struct apply
+                : is_same<typename add_const<I1>::type, typename add_const<I2>::type>
+            {};
+        };
+
+        template <>
+        struct equal_to_impl<iterator_facade_tag>
+        {
+            template <typename I1, typename I2>
+            struct apply : I1::template equal_to<I1, I2> {};
+        };
+
+        template <>
+        struct equal_to_impl<array_iterator_tag>;
+
+        template <>
+        struct equal_to_impl<mpl_iterator_tag>;
+
+        template <>
+        struct equal_to_impl<std_pair_iterator_tag>;
+    }
+
+    namespace result_of
+    {
+        template <typename I1, typename I2>
+        struct equal_to
+            : extension::equal_to_impl<typename detail::tag_of<I1>::type>::
+                template apply<I1, I2>
+        {};
+    }
+
+    namespace iterator_operators
+    {
+        template <typename Iter1, typename Iter2>
+        inline typename 
+        enable_if<
+            mpl::and_<is_fusion_iterator<Iter1>, is_fusion_iterator<Iter2> >
+            , bool
+            >::type
+        operator==(Iter1 const&, Iter2 const&)
+        {
+            return result_of::equal_to<Iter1, Iter2>::value;
+        }
+
+        template <typename Iter1, typename Iter2>
+        inline typename 
+        enable_if<
+            mpl::and_<is_fusion_iterator<Iter1>, is_fusion_iterator<Iter2> >
+            , bool
+            >::type
+        operator!=(Iter1 const&, Iter2 const&)
+        {
+            return !result_of::equal_to<Iter1, Iter2>::value;
+        }
+    }
+
+    using iterator_operators::operator==;
+    using iterator_operators::operator!=;
+}}
+
+#endif
+