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 |
387 | |