1
2#ifndef BOOST_MPL_PAIR_VIEW_HPP_INCLUDED
3#define BOOST_MPL_PAIR_VIEW_HPP_INCLUDED
4
5// Copyright David Abrahams 2003-2004
6// Copyright Aleksey Gurtovoy 2004
7//
8// Distributed under the Boost Software License, Version 1.0.
9// (See accompanying file LICENSE_1_0.txt or copy at
10// http://www.boost.org/LICENSE_1_0.txt)
11//
12// See http://www.boost.org/libs/mpl for documentation.
13
14// $Id$
15// $Date$
16// $Revision$
17
18#include <boost/mpl/begin_end.hpp>
19#include <boost/mpl/iterator_category.hpp>
20#include <boost/mpl/advance.hpp>
21#include <boost/mpl/distance.hpp>
22#include <boost/mpl/next_prior.hpp>
23#include <boost/mpl/deref.hpp>
24#include <boost/mpl/min_max.hpp>
25#include <boost/mpl/pair.hpp>
26#include <boost/mpl/iterator_tags.hpp>
27#include <boost/mpl/aux_/config/ctps.hpp>
28#include <boost/mpl/aux_/na_spec.hpp>
29
30namespace boost { namespace mpl {
31
32namespace aux {
33struct pair_iter_tag;
34
35#if defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
36
37template< typename Iter1, typename Iter2, typename Category >
38struct pair_iter;
39
40template< typename Category > struct prior_pair_iter
41{
42 template< typename Iter1, typename Iter2 > struct apply
43 {
44 typedef typename mpl::prior<Iter1>::type i1_;
45 typedef typename mpl::prior<Iter2>::type i2_;
46 typedef pair_iter<i1_,i2_,Category> type;
47 };
48};
49
50template<> struct prior_pair_iter<forward_iterator_tag>
51{
52 template< typename Iter1, typename Iter2 > struct apply
53 {
54 typedef pair_iter<Iter1,Iter2,forward_iterator_tag> type;
55 };
56};
57
58#endif
59}
60
61template<
62 typename Iter1
63 , typename Iter2
64 , typename Category
65 >
66struct pair_iter
67{
68 typedef aux::pair_iter_tag tag;
69 typedef Category category;
70 typedef Iter1 first;
71 typedef Iter2 second;
72
73#if defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
74 typedef pair<
75 typename deref<Iter1>::type
76 , typename deref<Iter2>::type
77 > type;
78
79 typedef typename mpl::next<Iter1>::type i1_;
80 typedef typename mpl::next<Iter2>::type i2_;
81 typedef pair_iter<i1_,i2_,Category> next;
82
83 typedef apply_wrap2< aux::prior_pair_iter<Category>,Iter1,Iter2 >::type prior;
84#endif
85};
86
87
88#if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
89
90template< typename Iter1, typename Iter2, typename C >
91struct deref< pair_iter<Iter1,Iter2,C> >
92{
93 typedef pair<
94 typename deref<Iter1>::type
95 , typename deref<Iter2>::type
96 > type;
97};
98
99template< typename Iter1, typename Iter2, typename C >
100struct next< pair_iter<Iter1,Iter2,C> >
101{
102 typedef typename mpl::next<Iter1>::type i1_;
103 typedef typename mpl::next<Iter2>::type i2_;
104 typedef pair_iter<i1_,i2_,C> type;
105};
106
107template< typename Iter1, typename Iter2, typename C >
108struct prior< pair_iter<Iter1,Iter2,C> >
109{
110 typedef typename mpl::prior<Iter1>::type i1_;
111 typedef typename mpl::prior<Iter2>::type i2_;
112 typedef pair_iter<i1_,i2_,C> type;
113};
114
115#endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
116
117
118template<> struct advance_impl<aux::pair_iter_tag>
119{
120 template< typename Iter, typename D > struct apply
121 {
122 typedef typename mpl::advance< typename Iter::first,D >::type i1_;
123 typedef typename mpl::advance< typename Iter::second,D >::type i2_;
124 typedef pair_iter<i1_,i2_,typename Iter::category> type;
125 };
126};
127
128template<> struct distance_impl<aux::pair_iter_tag>
129{
130 template< typename Iter1, typename Iter2 > struct apply
131 {
132 // agurt, 10/nov/04: MSVC 6.5 ICE-s on forwarding
133 typedef typename mpl::distance<
134 typename first<Iter1>::type
135 , typename first<Iter2>::type
136 >::type type;
137 };
138};
139
140
141template<
142 typename BOOST_MPL_AUX_NA_PARAM(Sequence1)
143 , typename BOOST_MPL_AUX_NA_PARAM(Sequence2)
144 >
145struct pair_view
146{
147 typedef nested_begin_end_tag tag;
148
149 typedef typename begin<Sequence1>::type iter1_;
150 typedef typename begin<Sequence2>::type iter2_;
151 typedef typename min<
152 typename iterator_category<iter1_>::type
153 , typename iterator_category<iter2_>::type
154 >::type category_;
155
156 typedef pair_iter<iter1_,iter2_,category_> begin;
157
158 typedef pair_iter<
159 typename end<Sequence1>::type
160 , typename end<Sequence2>::type
161 , category_
162 > end;
163};
164
165BOOST_MPL_AUX_NA_SPEC(2, pair_view)
166
167}}
168
169#endif // BOOST_MPL_PAIR_VIEW_HPP_INCLUDED
170

source code of include/boost/mpl/pair_view.hpp