1 /*=============================================================================
2     Copyright (c) 2001-2011 Joel de Guzman
3 
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_FUSION_ITERATOR_10012005_1551)
8 #define FUSION_FUSION_ITERATOR_10012005_1551
9 
10 #include <boost/fusion/support/config.hpp>
11 #include <boost/fusion/iterator/value_of.hpp>
12 #include <boost/fusion/iterator/next.hpp>
13 #include <boost/fusion/iterator/prior.hpp>
14 #include <boost/fusion/iterator/advance.hpp>
15 #include <boost/fusion/iterator/distance.hpp>
16 #include <boost/fusion/support/category_of.hpp>
17 #include <boost/mpl/next_prior.hpp>
18 #include <boost/mpl/advance_fwd.hpp>
19 #include <boost/mpl/distance_fwd.hpp>
20 #include <boost/mpl/iterator_tags.hpp>
21 #include <boost/mpl/eval_if.hpp>
22 #include <boost/type_traits/is_base_of.hpp>
23 
24 namespace boost { namespace fusion { namespace detail
25 {
26 
27 template<class Category>
28 struct to_mpl_category {
29     typedef typename mpl::eval_if<
30         is_base_of<random_access_traversal_tag, Category>,
31         mpl::random_access_iterator_tag,
32         mpl::eval_if<
33             is_base_of<bidirectional_traversal_tag, Category>,
34             mpl::bidirectional_iterator_tag,
35             mpl::forward_iterator_tag
36         >
37     >::type type;
38 };
39 
40 }}}
41 
42 namespace boost { namespace mpl
43 {
44     template <typename Iterator>
45     struct fusion_iterator
46     {
47         typedef typename fusion::result_of::value_of<Iterator>::type type;
48         typedef typename fusion::traits::category_of<Iterator>::type fusion_category;
49         typedef typename fusion::detail::to_mpl_category<fusion_category>::type category;
50         typedef Iterator iterator;
51     };
52 
53     template <typename Iterator>
54     struct next<fusion_iterator<Iterator> >
55     {
56         typedef fusion_iterator<typename fusion::result_of::next<Iterator>::type> type;
57     };
58 
59     template <typename Iterator>
60     struct prior<fusion_iterator<Iterator> >
61     {
62         typedef fusion_iterator<typename fusion::result_of::prior<Iterator>::type> type;
63     };
64 
65     template <typename Iterator, typename N>
66     struct advance<fusion_iterator<Iterator>, N>
67     {
68         typedef fusion_iterator<typename fusion::result_of::advance<Iterator, N>::type> type;
69     };
70 
71     template <typename First, typename Last>
72     struct distance<fusion_iterator<First>, fusion_iterator<Last> >
73         : fusion::result_of::distance<First, Last>
74     {};
75 
76 }}
77 
78 #endif
79 
80 
81