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1 | // Boost.Range library concept checks |
2 | // | |
3 | // Copyright Neil Groves 2009. Use, modification and distribution | |
4 | // are subject to the Boost Software License, Version 1.0. (See | |
5 | // accompanying file LICENSE_1_0.txt or copy at | |
6 | // http://www.boost.org/LICENSE_1_0.txt) | |
7 | // | |
8 | // Copyright Daniel Walker 2006. Use, modification and distribution | |
9 | // are subject to the Boost Software License, Version 1.0. (See | |
10 | // accompanying file LICENSE_1_0.txt or copy at | |
11 | // http://www.boost.org/LICENSE_1_0.txt) | |
12 | // | |
13 | // For more information, see http://www.boost.org/libs/range/ | |
14 | // | |
15 | ||
16 | #ifndef BOOST_RANGE_CONCEPTS_HPP | |
17 | #define BOOST_RANGE_CONCEPTS_HPP | |
18 | ||
19 | #include <boost/concept_check.hpp> | |
20 | #include <boost/iterator/iterator_concepts.hpp> | |
21 | #include <boost/range/begin.hpp> | |
22 | #include <boost/range/end.hpp> | |
23 | #include <boost/range/iterator.hpp> | |
24 | #include <boost/range/value_type.hpp> | |
25 | #include <boost/range/detail/misc_concept.hpp> | |
26 | #include <boost/type_traits/remove_reference.hpp> | |
27 | ||
28 | /*! | |
29 | * \file | |
30 | * \brief Concept checks for the Boost Range library. | |
31 | * | |
32 | * The structures in this file may be used in conjunction with the | |
33 | * Boost Concept Check library to insure that the type of a function | |
34 | * parameter is compatible with a range concept. If not, a meaningful | |
35 | * compile time error is generated. Checks are provided for the range | |
36 | * concepts related to iterator traversal categories. For example, the | |
37 | * following line checks that the type T models the ForwardRange | |
38 | * concept. | |
39 | * | |
40 | * \code | |
41 | * BOOST_CONCEPT_ASSERT((ForwardRangeConcept<T>)); | |
42 | * \endcode | |
43 | * | |
44 | * A different concept check is required to ensure writeable value | |
45 | * access. For example to check for a ForwardRange that can be written | |
46 | * to, the following code is required. | |
47 | * | |
48 | * \code | |
49 | * BOOST_CONCEPT_ASSERT((WriteableForwardRangeConcept<T>)); | |
50 | * \endcode | |
51 | * | |
52 | * \see http://www.boost.org/libs/range/doc/range.html for details | |
53 | * about range concepts. | |
54 | * \see http://www.boost.org/libs/iterator/doc/iterator_concepts.html | |
55 | * for details about iterator concepts. | |
56 | * \see http://www.boost.org/libs/concept_check/concept_check.htm for | |
57 | * details about concept checks. | |
58 | */ | |
59 | ||
60 | namespace boost { | |
61 | ||
62 | namespace range_detail { | |
63 | ||
64 | #ifndef BOOST_RANGE_ENABLE_CONCEPT_ASSERT | |
65 | ||
66 | // List broken compiler versions here: | |
67 | #ifndef __clang__ | |
68 | #ifdef __GNUC__ | |
69 | // GNUC 4.2 has strange issues correctly detecting compliance with the Concepts | |
70 | // hence the least disruptive approach is to turn-off the concept checking for | |
71 | // this version of the compiler. | |
72 | #if __GNUC__ == 4 && __GNUC_MINOR__ == 2 | |
73 | #define BOOST_RANGE_ENABLE_CONCEPT_ASSERT 0 | |
74 | #endif | |
75 | #endif | |
76 | ||
77 | #ifdef __GCCXML__ | |
78 | // GCC XML, unsurprisingly, has the same issues | |
79 | #if __GCCXML_GNUC__ == 4 && __GCCXML_GNUC_MINOR__ == 2 | |
80 | #define BOOST_RANGE_ENABLE_CONCEPT_ASSERT 0 | |
81 | #endif | |
82 | #endif | |
83 | #endif | |
84 | ||
85 | #ifdef __BORLANDC__ | |
86 | #define BOOST_RANGE_ENABLE_CONCEPT_ASSERT 0 | |
87 | #endif | |
88 | ||
89 | #ifdef __PATHCC__ | |
90 | #define BOOST_RANGE_ENABLE_CONCEPT_ASSERT 0 | |
91 | #endif | |
92 | ||
93 | // Default to using the concept asserts unless we have defined it off | |
94 | // during the search for black listed compilers. | |
95 | #ifndef BOOST_RANGE_ENABLE_CONCEPT_ASSERT | |
96 | #define BOOST_RANGE_ENABLE_CONCEPT_ASSERT 1 | |
97 | #endif | |
98 | ||
99 | #endif | |
100 | ||
101 | #if BOOST_RANGE_ENABLE_CONCEPT_ASSERT | |
102 | #define BOOST_RANGE_CONCEPT_ASSERT( x ) BOOST_CONCEPT_ASSERT( x ) | |
103 | #else | |
104 | #define BOOST_RANGE_CONCEPT_ASSERT( x ) | |
105 | #endif | |
106 | ||
107 | // Rationale for the inclusion of redefined iterator concept | |
108 | // classes: | |
109 | // | |
110 | // The Range algorithms often do not require that the iterators are | |
111 | // Assignable or default constructable, but the correct standard | |
112 | // conformant iterators do require the iterators to be a model of the | |
113 | // Assignable concept. | |
114 | // Iterators that contains a functor that is not assignable therefore | |
115 | // are not correct models of the standard iterator concepts, | |
116 | // despite being adequate for most algorithms. An example of this | |
117 | // use case is the combination of the boost::adaptors::filtered | |
118 | // class with a boost::lambda::bind generated functor. | |
119 | // Ultimately modeling the range concepts using composition | |
120 | // with the Boost.Iterator concepts would render the library | |
121 | // incompatible with many common Boost.Lambda expressions. | |
122 | template<class Iterator> | |
123 | struct IncrementableIteratorConcept : CopyConstructible<Iterator> | |
124 | { | |
125 | #if BOOST_RANGE_ENABLE_CONCEPT_ASSERT | |
126 | typedef BOOST_DEDUCED_TYPENAME iterator_traversal<Iterator>::type traversal_category; | |
127 | ||
128 | BOOST_RANGE_CONCEPT_ASSERT(( | |
129 | Convertible< | |
130 | traversal_category, | |
131 | incrementable_traversal_tag | |
132 | >)); | |
133 | ||
134 | BOOST_CONCEPT_USAGE(IncrementableIteratorConcept) | |
135 | { | |
136 | ++i; | |
137 | (void)i++; | |
138 | } | |
139 | private: | |
140 | Iterator i; | |
141 | #endif | |
142 | }; | |
143 | ||
144 | template<class Iterator> | |
145 | struct SinglePassIteratorConcept | |
146 | : IncrementableIteratorConcept<Iterator> | |
147 | , EqualityComparable<Iterator> | |
148 | { | |
149 | #if BOOST_RANGE_ENABLE_CONCEPT_ASSERT | |
150 | BOOST_RANGE_CONCEPT_ASSERT(( | |
151 | Convertible< | |
152 | BOOST_DEDUCED_TYPENAME SinglePassIteratorConcept::traversal_category, | |
153 | single_pass_traversal_tag | |
154 | >)); | |
155 | ||
156 | BOOST_CONCEPT_USAGE(SinglePassIteratorConcept) | |
157 | { | |
158 | Iterator i2(++i); | |
159 | boost::ignore_unused_variable_warning(i2); | |
160 | ||
161 | // deliberately we are loose with the postfix version for the single pass | |
162 | // iterator due to the commonly poor adherence to the specification means that | |
163 | // many algorithms would be unusable, whereas actually without the check they | |
164 | // work | |
165 | (void)(i++); | |
166 | ||
167 | BOOST_DEDUCED_TYPENAME boost::detail::iterator_traits<Iterator>::reference r1(*i); | |
168 | boost::ignore_unused_variable_warning(r1); | |
169 | ||
170 | BOOST_DEDUCED_TYPENAME boost::detail::iterator_traits<Iterator>::reference r2(*(++i)); | |
171 | boost::ignore_unused_variable_warning(r2); | |
172 | } | |
173 | private: | |
174 | Iterator i; | |
175 | #endif | |
176 | }; | |
177 | ||
178 | template<class Iterator> | |
179 | struct ForwardIteratorConcept | |
180 | : SinglePassIteratorConcept<Iterator> | |
181 | , DefaultConstructible<Iterator> | |
182 | { | |
183 | #if BOOST_RANGE_ENABLE_CONCEPT_ASSERT | |
184 | typedef BOOST_DEDUCED_TYPENAME boost::detail::iterator_traits<Iterator>::difference_type difference_type; | |
185 | ||
186 | BOOST_MPL_ASSERT((is_integral<difference_type>)); | |
187 | BOOST_MPL_ASSERT_RELATION(std::numeric_limits<difference_type>::is_signed, ==, true); | |
188 | ||
189 | BOOST_RANGE_CONCEPT_ASSERT(( | |
190 | Convertible< | |
191 | BOOST_DEDUCED_TYPENAME ForwardIteratorConcept::traversal_category, | |
192 | forward_traversal_tag | |
193 | >)); | |
194 | ||
195 | BOOST_CONCEPT_USAGE(ForwardIteratorConcept) | |
196 | { | |
197 | // See the above note in the SinglePassIteratorConcept about the handling of the | |
198 | // postfix increment. Since with forward and better iterators there is no need | |
199 | // for a proxy, we can sensibly require that the dereference result | |
200 | // is convertible to reference. | |
201 | Iterator i2(i++); | |
202 | boost::ignore_unused_variable_warning(i2); | |
203 | BOOST_DEDUCED_TYPENAME boost::detail::iterator_traits<Iterator>::reference r(*(i++)); | |
204 | boost::ignore_unused_variable_warning(r); | |
205 | } | |
206 | private: | |
207 | Iterator i; | |
208 | #endif | |
209 | }; | |
210 | ||
211 | template<class Iterator> | |
212 | struct BidirectionalIteratorConcept | |
213 | : ForwardIteratorConcept<Iterator> | |
214 | { | |
215 | #if BOOST_RANGE_ENABLE_CONCEPT_ASSERT | |
216 | BOOST_RANGE_CONCEPT_ASSERT(( | |
217 | Convertible< | |
218 | BOOST_DEDUCED_TYPENAME BidirectionalIteratorConcept::traversal_category, | |
219 | bidirectional_traversal_tag | |
220 | >)); | |
221 | ||
222 | BOOST_CONCEPT_USAGE(BidirectionalIteratorConcept) | |
223 | { | |
224 | --i; | |
225 | (void)i--; | |
226 | } | |
227 | private: | |
228 | Iterator i; | |
229 | #endif | |
230 | }; | |
231 | ||
232 | template<class Iterator> | |
233 | struct RandomAccessIteratorConcept | |
234 | : BidirectionalIteratorConcept<Iterator> | |
235 | { | |
236 | #if BOOST_RANGE_ENABLE_CONCEPT_ASSERT | |
237 | BOOST_RANGE_CONCEPT_ASSERT(( | |
238 | Convertible< | |
239 | BOOST_DEDUCED_TYPENAME RandomAccessIteratorConcept::traversal_category, | |
240 | random_access_traversal_tag | |
241 | >)); | |
242 | ||
243 | BOOST_CONCEPT_USAGE(RandomAccessIteratorConcept) | |
244 | { | |
245 | i += n; | |
246 | i = i + n; | |
247 | i = n + i; | |
248 | i -= n; | |
249 | i = i - n; | |
250 | n = i - j; | |
251 | } | |
252 | private: | |
253 | BOOST_DEDUCED_TYPENAME RandomAccessIteratorConcept::difference_type n; | |
254 | Iterator i; | |
255 | Iterator j; | |
256 | #endif | |
257 | }; | |
258 | ||
259 | } // namespace range_detail | |
260 | ||
261 | //! Check if a type T models the SinglePassRange range concept. | |
262 | template<class T> | |
263 | struct SinglePassRangeConcept | |
264 | { | |
265 | #if BOOST_RANGE_ENABLE_CONCEPT_ASSERT | |
266 | // A few compilers don't like the rvalue reference T types so just | |
267 | // remove it. | |
268 | typedef BOOST_DEDUCED_TYPENAME remove_reference<T>::type Rng; | |
269 | ||
270 | typedef BOOST_DEDUCED_TYPENAME range_iterator< | |
271 | Rng const | |
272 | >::type const_iterator; | |
273 | ||
274 | typedef BOOST_DEDUCED_TYPENAME range_iterator<Rng>::type iterator; | |
275 | ||
276 | BOOST_RANGE_CONCEPT_ASSERT(( | |
277 | range_detail::SinglePassIteratorConcept<iterator>)); | |
278 | ||
279 | BOOST_RANGE_CONCEPT_ASSERT(( | |
280 | range_detail::SinglePassIteratorConcept<const_iterator>)); | |
281 | ||
282 | BOOST_CONCEPT_USAGE(SinglePassRangeConcept) | |
283 | { | |
284 | // This has been modified from assigning to this->i | |
285 | // (where i was a member variable) to improve | |
286 | // compatibility with Boost.Lambda | |
287 | iterator i1 = boost::begin(*m_range); | |
288 | iterator i2 = boost::end(*m_range); | |
289 | ||
290 | boost::ignore_unused_variable_warning(i1); | |
291 | boost::ignore_unused_variable_warning(i2); | |
292 | ||
293 | const_constraints(*m_range); | |
294 | } | |
295 | ||
296 | private: | |
297 | void const_constraints(const Rng& const_range) | |
298 | { | |
299 | const_iterator ci1 = boost::begin(const_range); | |
300 | const_iterator ci2 = boost::end(const_range); | |
301 | ||
302 | boost::ignore_unused_variable_warning(ci1); | |
303 | boost::ignore_unused_variable_warning(ci2); | |
304 | } | |
305 | ||
306 | // Rationale: | |
307 | // The type of m_range is T* rather than T because it allows | |
308 | // T to be an abstract class. The other obvious alternative of | |
309 | // T& produces a warning on some compilers. | |
310 | Rng* m_range; | |
311 | #endif | |
312 | }; | |
313 | ||
314 | //! Check if a type T models the ForwardRange range concept. | |
315 | template<class T> | |
316 | struct ForwardRangeConcept : SinglePassRangeConcept<T> | |
317 | { | |
318 | #if BOOST_RANGE_ENABLE_CONCEPT_ASSERT | |
319 | BOOST_RANGE_CONCEPT_ASSERT((range_detail::ForwardIteratorConcept<BOOST_DEDUCED_TYPENAME ForwardRangeConcept::iterator>)); | |
320 | BOOST_RANGE_CONCEPT_ASSERT((range_detail::ForwardIteratorConcept<BOOST_DEDUCED_TYPENAME ForwardRangeConcept::const_iterator>)); | |
321 | #endif | |
322 | }; | |
323 | ||
324 | template<class T> | |
325 | struct WriteableRangeConcept | |
326 | { | |
327 | #if BOOST_RANGE_ENABLE_CONCEPT_ASSERT | |
328 | typedef BOOST_DEDUCED_TYPENAME range_iterator<T>::type iterator; | |
329 | ||
330 | BOOST_CONCEPT_USAGE(WriteableRangeConcept) | |
331 | { | |
332 | *i = v; | |
333 | } | |
334 | private: | |
335 | iterator i; | |
336 | BOOST_DEDUCED_TYPENAME range_value<T>::type v; | |
337 | #endif | |
338 | }; | |
339 | ||
340 | //! Check if a type T models the WriteableForwardRange range concept. | |
341 | template<class T> | |
342 | struct WriteableForwardRangeConcept | |
343 | : ForwardRangeConcept<T> | |
344 | , WriteableRangeConcept<T> | |
345 | { | |
346 | }; | |
347 | ||
348 | //! Check if a type T models the BidirectionalRange range concept. | |
349 | template<class T> | |
350 | struct BidirectionalRangeConcept : ForwardRangeConcept<T> | |
351 | { | |
352 | #if BOOST_RANGE_ENABLE_CONCEPT_ASSERT | |
353 | BOOST_RANGE_CONCEPT_ASSERT((range_detail::BidirectionalIteratorConcept<BOOST_DEDUCED_TYPENAME BidirectionalRangeConcept::iterator>)); | |
354 | BOOST_RANGE_CONCEPT_ASSERT((range_detail::BidirectionalIteratorConcept<BOOST_DEDUCED_TYPENAME BidirectionalRangeConcept::const_iterator>)); | |
355 | #endif | |
356 | }; | |
357 | ||
358 | //! Check if a type T models the WriteableBidirectionalRange range concept. | |
359 | template<class T> | |
360 | struct WriteableBidirectionalRangeConcept | |
361 | : BidirectionalRangeConcept<T> | |
362 | , WriteableRangeConcept<T> | |
363 | { | |
364 | }; | |
365 | ||
366 | //! Check if a type T models the RandomAccessRange range concept. | |
367 | template<class T> | |
368 | struct RandomAccessRangeConcept : BidirectionalRangeConcept<T> | |
369 | { | |
370 | #if BOOST_RANGE_ENABLE_CONCEPT_ASSERT | |
371 | BOOST_RANGE_CONCEPT_ASSERT((range_detail::RandomAccessIteratorConcept<BOOST_DEDUCED_TYPENAME RandomAccessRangeConcept::iterator>)); | |
372 | BOOST_RANGE_CONCEPT_ASSERT((range_detail::RandomAccessIteratorConcept<BOOST_DEDUCED_TYPENAME RandomAccessRangeConcept::const_iterator>)); | |
373 | #endif | |
374 | }; | |
375 | ||
376 | //! Check if a type T models the WriteableRandomAccessRange range concept. | |
377 | template<class T> | |
378 | struct WriteableRandomAccessRangeConcept | |
379 | : RandomAccessRangeConcept<T> | |
380 | , WriteableRangeConcept<T> | |
381 | { | |
382 | }; | |
383 | ||
384 | } // namespace boost | |
385 | ||
386 | #endif // BOOST_RANGE_CONCEPTS_HPP |