1 | |
2 | #ifndef BOOST_MPL_AUX_SINGLE_ELEMENT_ITER_HPP_INCLUDED |
3 | #define BOOST_MPL_AUX_SINGLE_ELEMENT_ITER_HPP_INCLUDED |
4 | |
5 | // Copyright Aleksey Gurtovoy 2000-2004 |
6 | // |
7 | // Distributed under the Boost Software License, Version 1.0. |
8 | // (See accompanying file LICENSE_1_0.txt or copy at |
9 | // http://www.boost.org/LICENSE_1_0.txt) |
10 | // |
11 | // See http://www.boost.org/libs/mpl for documentation. |
12 | |
13 | // $Id$ |
14 | // $Date$ |
15 | // $Revision$ |
16 | |
17 | #include <boost/mpl/iterator_tags.hpp> |
18 | #include <boost/mpl/advance_fwd.hpp> |
19 | #include <boost/mpl/distance_fwd.hpp> |
20 | #include <boost/mpl/next_prior.hpp> |
21 | #include <boost/mpl/deref.hpp> |
22 | #include <boost/mpl/int.hpp> |
23 | #include <boost/mpl/aux_/nttp_decl.hpp> |
24 | #include <boost/mpl/aux_/value_wknd.hpp> |
25 | #include <boost/mpl/aux_/config/ctps.hpp> |
26 | |
27 | namespace boost { namespace mpl { |
28 | |
29 | #if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION) |
30 | |
31 | namespace aux { |
32 | |
33 | template< typename T, BOOST_MPL_AUX_NTTP_DECL(int, is_last_) > |
34 | struct sel_iter; |
35 | |
36 | template< typename T > |
37 | struct sel_iter<T,0> |
38 | { |
39 | typedef random_access_iterator_tag category; |
40 | typedef sel_iter<T,1> next; |
41 | typedef T type; |
42 | }; |
43 | |
44 | template< typename T > |
45 | struct sel_iter<T,1> |
46 | { |
47 | typedef random_access_iterator_tag category; |
48 | typedef sel_iter<T,0> prior; |
49 | }; |
50 | |
51 | } // namespace aux |
52 | |
53 | template< typename T, BOOST_MPL_AUX_NTTP_DECL(int, is_last_), typename Distance > |
54 | struct advance< aux::sel_iter<T,is_last_>,Distance> |
55 | { |
56 | typedef aux::sel_iter< |
57 | T |
58 | , ( is_last_ + BOOST_MPL_AUX_NESTED_VALUE_WKND(int, Distance) ) |
59 | > type; |
60 | }; |
61 | |
62 | template< |
63 | typename T |
64 | , BOOST_MPL_AUX_NTTP_DECL(int, l1) |
65 | , BOOST_MPL_AUX_NTTP_DECL(int, l2) |
66 | > |
67 | struct distance< aux::sel_iter<T,l1>, aux::sel_iter<T,l2> > |
68 | : int_<( l2 - l1 )> |
69 | { |
70 | }; |
71 | |
72 | #else |
73 | |
74 | namespace aux { |
75 | |
76 | struct sel_iter_tag; |
77 | |
78 | template< typename T, BOOST_MPL_AUX_NTTP_DECL(int, is_last_) > |
79 | struct sel_iter |
80 | { |
81 | enum { pos_ = is_last_ }; |
82 | typedef aux::sel_iter_tag tag; |
83 | typedef random_access_iterator_tag category; |
84 | |
85 | typedef sel_iter<T,(is_last_ + 1)> next; |
86 | typedef sel_iter<T,(is_last_ - 1)> prior; |
87 | typedef T type; |
88 | }; |
89 | |
90 | } // namespace aux |
91 | |
92 | template<> struct advance_impl<aux::sel_iter_tag> |
93 | { |
94 | template< typename Iterator, typename N > struct apply |
95 | { |
96 | enum { pos_ = Iterator::pos_, n_ = N::value }; |
97 | typedef aux::sel_iter< |
98 | typename Iterator::type |
99 | , (pos_ + n_) |
100 | > type; |
101 | }; |
102 | }; |
103 | |
104 | template<> struct distance_impl<aux::sel_iter_tag> |
105 | { |
106 | template< typename Iter1, typename Iter2 > struct apply |
107 | { |
108 | enum { pos1_ = Iter1::pos_, pos2_ = Iter2::pos_ }; |
109 | typedef int_<( pos2_ - pos1_ )> type; |
110 | BOOST_STATIC_CONSTANT(int, value = ( pos2_ - pos1_ )); |
111 | }; |
112 | }; |
113 | |
114 | #endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION |
115 | |
116 | }} |
117 | |
118 | #endif // BOOST_MPL_AUX_SINGLE_ELEMENT_ITER_HPP_INCLUDED |
119 | |