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_DISTANCE_09172005_0721)
Chris@16: #define FUSION_DISTANCE_09172005_0721
Chris@16: 
Chris@101: #include <boost/fusion/support/config.hpp>
Chris@16: #include <boost/fusion/iterator/detail/distance.hpp>
Chris@16: #include <boost/fusion/support/category_of.hpp>
Chris@16: 
Chris@16: #include <boost/mpl/int.hpp>
Chris@16: #include <boost/mpl/assert.hpp>
Chris@16: #include <boost/type_traits/is_same.hpp>
Chris@16: 
Chris@16: #include <boost/fusion/support/tag_of.hpp>
Chris@16: 
Chris@16: namespace boost { namespace fusion
Chris@16: {
Chris@16:     struct random_access_traversal_tag;
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 distance_impl
Chris@16:         {
Chris@16:             // default implementation
Chris@16:             template <typename First, typename Last>
Chris@16:             struct apply : distance_detail::linear_distance<First, Last> 
Chris@16:             {};
Chris@16:         };
Chris@16: 
Chris@16:         template <>
Chris@16:         struct distance_impl<iterator_facade_tag>
Chris@16:         {
Chris@16:             template <typename First, typename Last>
Chris@16:             struct apply : First::template distance<First, Last> {};
Chris@16:         };
Chris@16: 
Chris@16:         template <>
Chris@16:         struct distance_impl<boost_array_iterator_tag>;
Chris@16: 
Chris@16:         template <>
Chris@16:         struct distance_impl<mpl_iterator_tag>;
Chris@16: 
Chris@16:         template <>
Chris@16:         struct distance_impl<std_pair_iterator_tag>;
Chris@16:     }
Chris@16: 
Chris@16:     namespace result_of
Chris@16:     {
Chris@16:         template <typename First, typename Last>
Chris@16:         struct distance
Chris@16:           : extension::distance_impl<typename detail::tag_of<First>::type>::
Chris@16:                 template apply<First, Last>
Chris@16:         {
Chris@16:             typedef typename extension::distance_impl<typename detail::tag_of<First>::type>:: 
Chris@16:             template apply<First, Last>::type distance_application;
Chris@16:             BOOST_STATIC_CONSTANT(int, value = distance_application::value);
Chris@16:         };
Chris@16:     }
Chris@16:         
Chris@16:     template <typename First, typename Last>
Chris@101:     BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
Chris@16:     inline typename result_of::distance<First, Last>::type
Chris@16:     distance(First const& a, Last const& b)
Chris@16:     {
Chris@16:         return result_of::distance<First, Last>::call(a,b);
Chris@16:     }
Chris@16: }}
Chris@16: 
Chris@16: #endif