1 /*=============================================================================
2 Copyright (c) 2001-2011 Joel de Guzman
4 Distributed under the Boost Software License, Version 1.0. (See accompanying
5 file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
6 ==============================================================================*/
7 #if !defined(FUSION_DISTANCE_09172005_0721)
8 #define FUSION_DISTANCE_09172005_0721
10 #include <boost/fusion/iterator/detail/distance.hpp>
11 #include <boost/fusion/support/category_of.hpp>
13 #include <boost/mpl/int.hpp>
14 #include <boost/mpl/assert.hpp>
15 #include <boost/type_traits/is_same.hpp>
17 #include <boost/fusion/support/tag_of.hpp>
19 namespace boost { namespace fusion
21 struct random_access_traversal_tag;
24 struct iterator_facade_tag; // iterator facade tag
25 struct boost_array_iterator_tag; // boost::array iterator tag
26 struct mpl_iterator_tag; // mpl sequence iterator tag
27 struct std_pair_iterator_tag; // std::pair iterator tag
31 template <typename Tag>
34 // default implementation
35 template <typename First, typename Last>
36 struct apply : distance_detail::linear_distance<First, Last>
41 struct distance_impl<iterator_facade_tag>
43 template <typename First, typename Last>
44 struct apply : First::template distance<First, Last> {};
48 struct distance_impl<boost_array_iterator_tag>;
51 struct distance_impl<mpl_iterator_tag>;
54 struct distance_impl<std_pair_iterator_tag>;
59 template <typename First, typename Last>
61 : extension::distance_impl<typename detail::tag_of<First>::type>::
62 template apply<First, Last>
64 typedef typename extension::distance_impl<typename detail::tag_of<First>::type>::
65 template apply<First, Last>::type distance_application;
66 BOOST_STATIC_CONSTANT(int, value = distance_application::value);
70 template <typename First, typename Last>
71 inline typename result_of::distance<First, Last>::type
72 distance(First const& a, Last const& b)
74 return result_of::distance<First, Last>::call(a,b);