Chris@16: /*=============================================================================
Chris@16:     Copyright (c) 2001-2011 Joel de Guzman
Chris@16: 
Chris@16:     Distributed under the Boost Software License, Version 1.0. (See accompanying
Chris@16:     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@16: ==============================================================================*/
Chris@16: #if !defined(FUSION_EQUAL_TO_05052005_1208)
Chris@16: #define FUSION_EQUAL_TO_05052005_1208
Chris@16: 
Chris@101: #include <boost/fusion/support/config.hpp>
Chris@16: #include <boost/type_traits/is_same.hpp>
Chris@16: #include <boost/fusion/support/tag_of.hpp>
Chris@16: #include <boost/type_traits/add_const.hpp>
Chris@16: #include <boost/fusion/support/is_iterator.hpp>
Chris@16: #include <boost/mpl/and.hpp>
Chris@16: #include <boost/utility/enable_if.hpp>
Chris@16: 
Chris@16: namespace boost { namespace fusion
Chris@16: {
Chris@16:     // Special tags:
Chris@16:     struct iterator_facade_tag; // iterator facade tag
Chris@16:     struct boost_array_iterator_tag; // boost::array iterator tag
Chris@16:     struct mpl_iterator_tag; // mpl sequence iterator tag
Chris@16:     struct std_pair_iterator_tag; // std::pair iterator tag
Chris@16: 
Chris@16:     namespace extension
Chris@16:     {
Chris@16:         template <typename Tag>
Chris@16:         struct equal_to_impl
Chris@16:         {
Chris@16:             // default implementation
Chris@16:             template <typename I1, typename I2>
Chris@16:             struct apply
Chris@16:                 : is_same<typename add_const<I1>::type, typename add_const<I2>::type>
Chris@16:             {};
Chris@16:         };
Chris@16: 
Chris@16:         template <>
Chris@16:         struct equal_to_impl<iterator_facade_tag>
Chris@16:         {
Chris@16:             template <typename It1, typename It2, typename Tag1, typename Tag2>
Chris@16:             struct dispatch : mpl::false_ {};
Chris@16: 
Chris@16:             template <typename It1, typename It2, typename Tag>
Chris@16:             struct dispatch<It1, It2, Tag, Tag> // same tag
Chris@16:               : It1::template equal_to<It1, It2>
Chris@16:             {};
Chris@16: 
Chris@16:             template<typename It1, typename It2>
Chris@16:             struct apply : dispatch<It1, It2,
Chris@16:                 typename It1::fusion_tag, typename It2::fusion_tag>
Chris@16:             {};
Chris@16:         };
Chris@16: 
Chris@16:         template <>
Chris@16:         struct equal_to_impl<boost_array_iterator_tag>;
Chris@16: 
Chris@16:         template <>
Chris@16:         struct equal_to_impl<mpl_iterator_tag>;
Chris@16: 
Chris@16:         template <>
Chris@16:         struct equal_to_impl<std_pair_iterator_tag>;
Chris@16:     }
Chris@16: 
Chris@16:     namespace result_of
Chris@16:     {
Chris@16:         template <typename I1, typename I2>
Chris@16:         struct equal_to
Chris@16:             : extension::equal_to_impl<typename detail::tag_of<I1>::type>::
Chris@16:                 template apply<I1, I2>
Chris@16:         {};
Chris@16:     }
Chris@16: 
Chris@16:     namespace iterator_operators
Chris@16:     {
Chris@16:         template <typename Iter1, typename Iter2>
Chris@101:         BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
Chris@16:         inline typename
Chris@16:         boost::enable_if<
Chris@16:             mpl::and_<is_fusion_iterator<Iter1>, is_fusion_iterator<Iter2> >
Chris@16:             , bool
Chris@16:             >::type
Chris@16:         operator==(Iter1 const&, Iter2 const&)
Chris@16:         {
Chris@16:             return result_of::equal_to<Iter1, Iter2>::value;
Chris@16:         }
Chris@16: 
Chris@16:         template <typename Iter1, typename Iter2>
Chris@101:         BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
Chris@16:         inline typename
Chris@16:         boost::enable_if<
Chris@16:             mpl::and_<is_fusion_iterator<Iter1>, is_fusion_iterator<Iter2> >
Chris@16:             , bool
Chris@16:             >::type
Chris@16:         operator!=(Iter1 const&, Iter2 const&)
Chris@16:         {
Chris@16:             return !result_of::equal_to<Iter1, Iter2>::value;
Chris@16:         }
Chris@16:     }
Chris@16: 
Chris@16:     using iterator_operators::operator==;
Chris@16:     using iterator_operators::operator!=;
Chris@16: }}
Chris@16: 
Chris@16: #endif
Chris@16: