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1 | /////////////////////////////////////////////////////////////////////////////// |
2 | /// \file iterator.hpp | |
3 | /// Proto callables for std functions found in \<iterator\> | |
4 | // | |
5 | // Copyright 2012 Eric Niebler. Distributed under the Boost | |
6 | // Software License, Version 1.0. (See accompanying file | |
7 | // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) | |
8 | ||
9 | #ifndef BOOST_PROTO_FUNCTIONAL_STD_ITERATOR_HPP_EAN_27_08_2012 | |
10 | #define BOOST_PROTO_FUNCTIONAL_STD_ITERATOR_HPP_EAN_27_08_2012 | |
11 | ||
12 | #include <iterator> | |
13 | #include <boost/type_traits/remove_const.hpp> | |
14 | #include <boost/type_traits/remove_reference.hpp> | |
15 | #include <boost/proto/proto_fwd.hpp> | |
16 | ||
17 | namespace boost { namespace proto { namespace functional | |
18 | { | |
19 | ||
20 | // A PolymorphicFunctionObject wrapping std::advance | |
21 | struct advance | |
22 | { | |
23 | BOOST_PROTO_CALLABLE() | |
24 | ||
25 | typedef void result_type; | |
26 | ||
27 | template<typename InputIterator, typename Distance> | |
28 | void operator()(InputIterator &x, Distance n) const | |
29 | { | |
30 | std::advance(x, n); | |
31 | } | |
32 | }; | |
33 | ||
34 | // A PolymorphicFunctionObject wrapping std::distance | |
35 | struct distance | |
36 | { | |
37 | BOOST_PROTO_CALLABLE() | |
38 | ||
39 | template<typename Sig> | |
40 | struct result; | |
41 | ||
42 | template<typename This, typename InputIter1, typename InputIter2> | |
43 | struct result<This(InputIter1, InputIter2)> | |
44 | { | |
45 | typedef | |
46 | typename std::iterator_traits< | |
47 | typename boost::remove_const< | |
48 | typename boost::remove_reference<InputIter1>::type | |
49 | >::type | |
50 | >::difference_type | |
51 | type; | |
52 | }; | |
53 | ||
54 | template<typename InputIterator> | |
55 | typename std::iterator_traits<InputIterator>::difference_type | |
56 | operator()(InputIterator first, InputIterator last) const | |
57 | { | |
58 | return std::distance(first, last); | |
59 | } | |
60 | }; | |
61 | ||
62 | // A PolymorphicFunctionObject wrapping std::next | |
63 | struct next | |
64 | { | |
65 | BOOST_PROTO_CALLABLE() | |
66 | ||
67 | template<typename Sig> | |
68 | struct result; | |
69 | ||
70 | template<typename This, typename ForwardIterator> | |
71 | struct result<This(ForwardIterator)> | |
72 | { | |
73 | typedef | |
74 | typename boost::remove_const< | |
75 | typename boost::remove_reference<ForwardIterator>::type | |
76 | >::type | |
77 | type; | |
78 | }; | |
79 | ||
80 | template<typename This, typename ForwardIterator, typename Distance> | |
81 | struct result<This(ForwardIterator, Distance)> | |
82 | { | |
83 | typedef | |
84 | typename boost::remove_const< | |
85 | typename boost::remove_reference<ForwardIterator>::type | |
86 | >::type | |
87 | type; | |
88 | }; | |
89 | ||
90 | template<typename ForwardIterator> | |
91 | ForwardIterator operator()(ForwardIterator x) const | |
92 | { | |
93 | return std::advance( | |
94 | x | |
95 | , static_cast<typename std::iterator_traits<ForwardIterator>::difference_type>(1) | |
96 | ); | |
97 | } | |
98 | ||
99 | template<typename ForwardIterator> | |
100 | ForwardIterator operator()( | |
101 | ForwardIterator x | |
102 | , typename std::iterator_traits<ForwardIterator>::difference_type n | |
103 | ) const | |
104 | { | |
105 | return std::advance(x, n); | |
106 | } | |
107 | }; | |
108 | ||
109 | // A PolymorphicFunctionObject wrapping std::prior | |
110 | struct prior | |
111 | { | |
112 | BOOST_PROTO_CALLABLE() | |
113 | ||
114 | template<typename Sig> | |
115 | struct result; | |
116 | ||
117 | template<typename This, typename BidirectionalIterator> | |
118 | struct result<This(BidirectionalIterator)> | |
119 | { | |
120 | typedef | |
121 | typename boost::remove_const< | |
122 | typename boost::remove_reference<BidirectionalIterator>::type | |
123 | >::type | |
124 | type; | |
125 | }; | |
126 | ||
127 | template<typename This, typename BidirectionalIterator, typename Distance> | |
128 | struct result<This(BidirectionalIterator, Distance)> | |
129 | { | |
130 | typedef | |
131 | typename boost::remove_const< | |
132 | typename boost::remove_reference<BidirectionalIterator>::type | |
133 | >::type | |
134 | type; | |
135 | }; | |
136 | ||
137 | template<typename BidirectionalIterator> | |
138 | BidirectionalIterator operator()(BidirectionalIterator x) const | |
139 | { | |
140 | return std::advance( | |
141 | x | |
142 | , -static_cast<typename std::iterator_traits<BidirectionalIterator>::difference_type>(1) | |
143 | ); | |
144 | } | |
145 | ||
146 | template<typename BidirectionalIterator> | |
147 | BidirectionalIterator operator()( | |
148 | BidirectionalIterator x | |
149 | , typename std::iterator_traits<BidirectionalIterator>::difference_type n | |
150 | ) const | |
151 | { | |
152 | return std::advance(x, -n); | |
153 | } | |
154 | }; | |
155 | ||
156 | }}} | |
157 | ||
158 | #endif |