1// (C) Copyright Jeremy Siek 2002.
2// Distributed under the Boost Software License, Version 1.0. (See
3// accompanying file LICENSE_1_0.txt or copy at
4// http://www.boost.org/LICENSE_1_0.txt)
5
6#ifndef BOOST_ITERATOR_CONCEPTS_HPP
7#define BOOST_ITERATOR_CONCEPTS_HPP
8
9#include <boost/concept_check.hpp>
10#include <boost/iterator/iterator_categories.hpp>
11
12// Use boost::detail::iterator_traits to work around some MSVC/Dinkumware problems.
13#include <boost/detail/iterator.hpp>
14
15#include <boost/type_traits/is_same.hpp>
16#include <boost/type_traits/is_integral.hpp>
17
18#include <boost/mpl/bool.hpp>
19#include <boost/mpl/if.hpp>
20#include <boost/mpl/and.hpp>
21#include <boost/mpl/or.hpp>
22
23#include <boost/static_assert.hpp>
24
25// Use boost/limits to work around missing limits headers on some compilers
26#include <boost/limits.hpp>
27#include <boost/config.hpp>
28
29#include <algorithm>
30
31#include <boost/concept/detail/concept_def.hpp>
32
33namespace boost_concepts
34{
35 // Used a different namespace here (instead of "boost") so that the
36 // concept descriptions do not take for granted the names in
37 // namespace boost.
38
39 //===========================================================================
40 // Iterator Access Concepts
41
42 BOOST_concept(ReadableIterator,(Iterator))
43 : boost::Assignable<Iterator>
44 , boost::CopyConstructible<Iterator>
45
46 {
47 typedef BOOST_DEDUCED_TYPENAME boost::detail::iterator_traits<Iterator>::value_type value_type;
48 typedef BOOST_DEDUCED_TYPENAME boost::detail::iterator_traits<Iterator>::reference reference;
49
50 BOOST_CONCEPT_USAGE(ReadableIterator)
51 {
52
53 value_type v = *i;
54 boost::ignore_unused_variable_warning(v);
55 }
56 private:
57 Iterator i;
58 };
59
60 template <
61 typename Iterator
62 , typename ValueType = BOOST_DEDUCED_TYPENAME boost::detail::iterator_traits<Iterator>::value_type
63 >
64 struct WritableIterator
65 : boost::CopyConstructible<Iterator>
66 {
67 BOOST_CONCEPT_USAGE(WritableIterator)
68 {
69 *i = v;
70 }
71 private:
72 ValueType v;
73 Iterator i;
74 };
75
76 template <
77 typename Iterator
78 , typename ValueType = BOOST_DEDUCED_TYPENAME boost::detail::iterator_traits<Iterator>::value_type
79 >
80 struct WritableIteratorConcept : WritableIterator<Iterator,ValueType> {};
81
82 BOOST_concept(SwappableIterator,(Iterator))
83 {
84 BOOST_CONCEPT_USAGE(SwappableIterator)
85 {
86 std::iter_swap(i1, i2);
87 }
88 private:
89 Iterator i1;
90 Iterator i2;
91 };
92
93 BOOST_concept(LvalueIterator,(Iterator))
94 {
95 typedef typename boost::detail::iterator_traits<Iterator>::value_type value_type;
96
97 BOOST_CONCEPT_USAGE(LvalueIterator)
98 {
99 value_type& r = const_cast<value_type&>(*i);
100 boost::ignore_unused_variable_warning(r);
101 }
102 private:
103 Iterator i;
104 };
105
106
107 //===========================================================================
108 // Iterator Traversal Concepts
109
110 BOOST_concept(IncrementableIterator,(Iterator))
111 : boost::Assignable<Iterator>
112 , boost::CopyConstructible<Iterator>
113 {
114 typedef typename boost::iterator_traversal<Iterator>::type traversal_category;
115
116 BOOST_CONCEPT_ASSERT((
117 boost::Convertible<
118 traversal_category
119 , boost::incrementable_traversal_tag
120 >));
121
122 BOOST_CONCEPT_USAGE(IncrementableIterator)
123 {
124 ++i;
125 (void)i++;
126 }
127 private:
128 Iterator i;
129 };
130
131 BOOST_concept(SinglePassIterator,(Iterator))
132 : IncrementableIterator<Iterator>
133 , boost::EqualityComparable<Iterator>
134
135 {
136 BOOST_CONCEPT_ASSERT((
137 boost::Convertible<
138 BOOST_DEDUCED_TYPENAME SinglePassIterator::traversal_category
139 , boost::single_pass_traversal_tag
140 > ));
141 };
142
143 BOOST_concept(ForwardTraversal,(Iterator))
144 : SinglePassIterator<Iterator>
145 , boost::DefaultConstructible<Iterator>
146 {
147 typedef typename boost::detail::iterator_traits<Iterator>::difference_type difference_type;
148
149 BOOST_MPL_ASSERT((boost::is_integral<difference_type>));
150 BOOST_MPL_ASSERT_RELATION(std::numeric_limits<difference_type>::is_signed, ==, true);
151
152 BOOST_CONCEPT_ASSERT((
153 boost::Convertible<
154 BOOST_DEDUCED_TYPENAME ForwardTraversal::traversal_category
155 , boost::forward_traversal_tag
156 > ));
157 };
158
159 BOOST_concept(BidirectionalTraversal,(Iterator))
160 : ForwardTraversal<Iterator>
161 {
162 BOOST_CONCEPT_ASSERT((
163 boost::Convertible<
164 BOOST_DEDUCED_TYPENAME BidirectionalTraversal::traversal_category
165 , boost::bidirectional_traversal_tag
166 > ));
167
168 BOOST_CONCEPT_USAGE(BidirectionalTraversal)
169 {
170 --i;
171 (void)i--;
172 }
173 private:
174 Iterator i;
175 };
176
177 BOOST_concept(RandomAccessTraversal,(Iterator))
178 : BidirectionalTraversal<Iterator>
179 {
180 BOOST_CONCEPT_ASSERT((
181 boost::Convertible<
182 BOOST_DEDUCED_TYPENAME RandomAccessTraversal::traversal_category
183 , boost::random_access_traversal_tag
184 > ));
185
186 BOOST_CONCEPT_USAGE(RandomAccessTraversal)
187 {
188 i += n;
189 i = i + n;
190 i = n + i;
191 i -= n;
192 i = i - n;
193 n = i - j;
194 }
195
196 private:
197 typename BidirectionalTraversal<Iterator>::difference_type n;
198 Iterator i, j;
199 };
200
201 //===========================================================================
202 // Iterator Interoperability
203
204 namespace detail
205 {
206 template <typename Iterator1, typename Iterator2>
207 void interop_single_pass_constraints(Iterator1 const& i1, Iterator2 const& i2)
208 {
209 bool b;
210 b = i1 == i2;
211 b = i1 != i2;
212
213 b = i2 == i1;
214 b = i2 != i1;
215 boost::ignore_unused_variable_warning(b);
216 }
217
218 template <typename Iterator1, typename Iterator2>
219 void interop_rand_access_constraints(
220 Iterator1 const& i1, Iterator2 const& i2,
221 boost::random_access_traversal_tag, boost::random_access_traversal_tag)
222 {
223 bool b;
224 typename boost::detail::iterator_traits<Iterator2>::difference_type n;
225 b = i1 < i2;
226 b = i1 <= i2;
227 b = i1 > i2;
228 b = i1 >= i2;
229 n = i1 - i2;
230
231 b = i2 < i1;
232 b = i2 <= i1;
233 b = i2 > i1;
234 b = i2 >= i1;
235 n = i2 - i1;
236 boost::ignore_unused_variable_warning(b);
237 boost::ignore_unused_variable_warning(n);
238 }
239
240 template <typename Iterator1, typename Iterator2>
241 void interop_rand_access_constraints(
242 Iterator1 const&, Iterator2 const&,
243 boost::single_pass_traversal_tag, boost::single_pass_traversal_tag)
244 { }
245
246 } // namespace detail
247
248 BOOST_concept(InteroperableIterator,(Iterator)(ConstIterator))
249 {
250 private:
251 typedef typename boost::iterators::pure_iterator_traversal<Iterator>::type traversal_category;
252 typedef typename boost::iterators::pure_iterator_traversal<ConstIterator>::type const_traversal_category;
253
254 public:
255 BOOST_CONCEPT_ASSERT((SinglePassIterator<Iterator>));
256 BOOST_CONCEPT_ASSERT((SinglePassIterator<ConstIterator>));
257
258 BOOST_CONCEPT_USAGE(InteroperableIterator)
259 {
260 detail::interop_single_pass_constraints(i, ci);
261 detail::interop_rand_access_constraints(i, ci, traversal_category(), const_traversal_category());
262
263 ci = i;
264 }
265
266 private:
267 Iterator i;
268 ConstIterator ci;
269 };
270
271} // namespace boost_concepts
272
273#include <boost/concept/detail/concept_undef.hpp>
274
275#endif // BOOST_ITERATOR_CONCEPTS_HPP
276

source code of boost/boost/iterator/iterator_concepts.hpp