1 /*=============================================================================
2     Copyright (c) 2001-2011 Joel de Guzman
3     Copyright (c) 2005 Eric Niebler
4 
5     Distributed under the Boost Software License, Version 1.0. (See accompanying
6     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
7 ==============================================================================*/
8 #if !defined(FUSION_CONS_ITERATOR_07172005_0849)
9 #define FUSION_CONS_ITERATOR_07172005_0849
10 
11 #include <boost/fusion/support/config.hpp>
12 #include <boost/type_traits/add_const.hpp>
13 #include <boost/fusion/support/iterator_base.hpp>
14 #include <boost/fusion/container/list/detail/deref_impl.hpp>
15 #include <boost/fusion/container/list/detail/next_impl.hpp>
16 #include <boost/fusion/container/list/detail/value_of_impl.hpp>
17 #include <boost/fusion/container/list/detail/equal_to_impl.hpp>
18 #include <boost/fusion/container/list/list_fwd.hpp>
19 
20 namespace boost { namespace fusion
21 {
22     struct nil_;
23     struct cons_iterator_tag;
24     struct forward_traversal_tag;
25 
26     template <typename Cons>
27     struct cons_iterator_identity;
28 
29     template <typename Cons = nil_>
30     struct cons_iterator : iterator_base<cons_iterator<Cons> >
31     {
32         typedef cons_iterator_tag fusion_tag;
33         typedef forward_traversal_tag category;
34         typedef Cons cons_type;
35         typedef cons_iterator_identity<
36             typename add_const<Cons>::type>
37         identity;
38 
39         BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
cons_iteratorboost::fusion::cons_iterator40         explicit cons_iterator(cons_type& in_cons) BOOST_NOEXCEPT
41             : cons(in_cons) {}
42 
43         cons_type& cons;
44 
45     private:
46         // silence MSVC warning C4512: assignment operator could not be generated
47         cons_iterator& operator= (cons_iterator const&);
48     };
49 
50     struct nil_iterator : iterator_base<nil_iterator>
51     {
52         typedef forward_traversal_tag category;
53         typedef cons_iterator_tag fusion_tag;
54         typedef nil_ cons_type;
55         typedef cons_iterator_identity<
56             add_const<nil_>::type>
57         identity;
58 
59         BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
nil_iteratorboost::fusion::nil_iterator60         nil_iterator() BOOST_NOEXCEPT {}
61         BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
nil_iteratorboost::fusion::nil_iterator62         explicit nil_iterator(nil_ const&) BOOST_NOEXCEPT {}
63     };
64 
65     template <>
66     struct cons_iterator<nil_> : nil_iterator
67     {
68         BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
cons_iteratorboost::fusion::cons_iterator69         cons_iterator() BOOST_NOEXCEPT {}
70         BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
cons_iteratorboost::fusion::cons_iterator71         explicit cons_iterator(nil_ const&) BOOST_NOEXCEPT {}
72     };
73 
74     template <>
75     struct cons_iterator<nil_ const> : nil_iterator
76     {
77         BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
cons_iteratorboost::fusion::cons_iterator78         cons_iterator() BOOST_NOEXCEPT {}
79         BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
cons_iteratorboost::fusion::cons_iterator80         explicit cons_iterator(nil_ const&) BOOST_NOEXCEPT {}
81     };
82 
83     template <>
84     struct cons_iterator<list<> > : nil_iterator
85     {
86         BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
87         cons_iterator() BOOST_NOEXCEPT {}
88         BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
89         explicit cons_iterator(nil_ const&) BOOST_NOEXCEPT {}
90     };
91 
92     template <>
93     struct cons_iterator<list<> const> : nil_iterator
94     {
95         BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
96         cons_iterator() BOOST_NOEXCEPT {}
97         BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
98         explicit cons_iterator(nil_ const&) BOOST_NOEXCEPT {}
99     };
100 }}
101 
102 #ifdef BOOST_FUSION_WORKAROUND_FOR_LWG_2408
103 namespace std
104 {
105     template <typename Cons>
106     struct iterator_traits< ::boost::fusion::cons_iterator<Cons> >
107     { };
108 }
109 #endif
110 
111 #endif
112