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366 lines
13 KiB
366 lines
13 KiB
// Boost.Range library concept checks |
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// |
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// Copyright Neil Groves 2009. Use, modification and distribution |
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// are subject to the Boost Software License, Version 1.0. (See |
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// accompanying file LICENSE_1_0.txt or copy at |
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// http://www.boost.org/LICENSE_1_0.txt) |
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// |
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// Copyright Daniel Walker 2006. Use, modification and distribution |
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// are subject to the Boost Software License, Version 1.0. (See |
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// accompanying file LICENSE_1_0.txt or copy at |
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// http://www.boost.org/LICENSE_1_0.txt) |
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// |
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// For more information, see http://www.boost.org/libs/range/ |
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// |
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#ifndef BOOST_RANGE_CONCEPTS_HPP |
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#define BOOST_RANGE_CONCEPTS_HPP |
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#include <boost/concept_check.hpp> |
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#include <boost/iterator/iterator_concepts.hpp> |
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#include <boost/range/begin.hpp> |
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#include <boost/range/end.hpp> |
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#include <boost/range/iterator.hpp> |
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#include <boost/range/value_type.hpp> |
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#include <boost/range/detail/misc_concept.hpp> |
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/*! |
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* \file |
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* \brief Concept checks for the Boost Range library. |
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* |
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* The structures in this file may be used in conjunction with the |
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* Boost Concept Check library to insure that the type of a function |
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* parameter is compatible with a range concept. If not, a meaningful |
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* compile time error is generated. Checks are provided for the range |
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* concepts related to iterator traversal categories. For example, the |
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* following line checks that the type T models the ForwardRange |
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* concept. |
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* |
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* \code |
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* BOOST_CONCEPT_ASSERT((ForwardRangeConcept<T>)); |
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* \endcode |
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* |
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* A different concept check is required to ensure writeable value |
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* access. For example to check for a ForwardRange that can be written |
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* to, the following code is required. |
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* |
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* \code |
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* BOOST_CONCEPT_ASSERT((WriteableForwardRangeConcept<T>)); |
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* \endcode |
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* |
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* \see http://www.boost.org/libs/range/doc/range.html for details |
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* about range concepts. |
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* \see http://www.boost.org/libs/iterator/doc/iterator_concepts.html |
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* for details about iterator concepts. |
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* \see http://www.boost.org/libs/concept_check/concept_check.htm for |
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* details about concept checks. |
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*/ |
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namespace boost { |
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namespace range_detail { |
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#ifndef BOOST_RANGE_ENABLE_CONCEPT_ASSERT |
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// List broken compiler versions here: |
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#ifdef __GNUC__ |
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// GNUC 4.2 has strange issues correctly detecting compliance with the Concepts |
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// hence the least disruptive approach is to turn-off the concept checking for |
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// this version of the compiler. |
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#if __GNUC__ == 4 && __GNUC_MINOR__ == 2 |
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#define BOOST_RANGE_ENABLE_CONCEPT_ASSERT 0 |
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#endif |
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#endif |
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#ifdef __BORLANDC__ |
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#define BOOST_RANGE_ENABLE_CONCEPT_ASSERT 0 |
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#endif |
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#ifdef __PATHCC__ |
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#define BOOST_RANGE_ENABLE_CONCEPT_ASSERT 0 |
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#endif |
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// Default to using the concept asserts unless we have defined it off |
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// during the search for black listed compilers. |
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#ifndef BOOST_RANGE_ENABLE_CONCEPT_ASSERT |
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#define BOOST_RANGE_ENABLE_CONCEPT_ASSERT 1 |
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#endif |
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#endif |
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#if BOOST_RANGE_ENABLE_CONCEPT_ASSERT |
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#define BOOST_RANGE_CONCEPT_ASSERT( x ) BOOST_CONCEPT_ASSERT( x ) |
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#else |
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#define BOOST_RANGE_CONCEPT_ASSERT( x ) |
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#endif |
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// Rationale for the inclusion of redefined iterator concept |
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// classes: |
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// |
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// The Range algorithms often do not require that the iterators are |
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// Assignable or default constructable, but the correct standard |
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// conformant iterators do require the iterators to be a model of the |
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// Assignable concept. |
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// Iterators that contains a functor that is not assignable therefore |
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// are not correct models of the standard iterator concepts, |
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// despite being adequate for most algorithms. An example of this |
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// use case is the combination of the boost::adaptors::filtered |
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// class with a boost::lambda::bind generated functor. |
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// Ultimately modeling the range concepts using composition |
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// with the Boost.Iterator concepts would render the library |
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// incompatible with many common Boost.Lambda expressions. |
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template<class Iterator> |
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struct IncrementableIteratorConcept : CopyConstructible<Iterator> |
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{ |
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#if BOOST_RANGE_ENABLE_CONCEPT_ASSERT |
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typedef BOOST_DEDUCED_TYPENAME iterator_traversal<Iterator>::type traversal_category; |
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BOOST_RANGE_CONCEPT_ASSERT(( |
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Convertible< |
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traversal_category, |
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incrementable_traversal_tag |
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>)); |
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BOOST_CONCEPT_USAGE(IncrementableIteratorConcept) |
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{ |
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++i; |
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(void)i++; |
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} |
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private: |
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Iterator i; |
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#endif |
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}; |
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template<class Iterator> |
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struct SinglePassIteratorConcept |
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: IncrementableIteratorConcept<Iterator> |
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, EqualityComparable<Iterator> |
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{ |
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#if BOOST_RANGE_ENABLE_CONCEPT_ASSERT |
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BOOST_RANGE_CONCEPT_ASSERT(( |
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Convertible< |
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BOOST_DEDUCED_TYPENAME SinglePassIteratorConcept::traversal_category, |
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single_pass_traversal_tag |
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>)); |
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BOOST_CONCEPT_USAGE(SinglePassIteratorConcept) |
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{ |
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Iterator i2(++i); |
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boost::ignore_unused_variable_warning(i2); |
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// deliberately we are loose with the postfix version for the single pass |
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// iterator due to the commonly poor adherence to the specification means that |
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// many algorithms would be unusable, whereas actually without the check they |
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// work |
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(void)(i++); |
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BOOST_DEDUCED_TYPENAME boost::detail::iterator_traits<Iterator>::reference r1(*i); |
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boost::ignore_unused_variable_warning(r1); |
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BOOST_DEDUCED_TYPENAME boost::detail::iterator_traits<Iterator>::reference r2(*(++i)); |
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boost::ignore_unused_variable_warning(r2); |
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} |
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private: |
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Iterator i; |
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#endif |
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}; |
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template<class Iterator> |
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struct ForwardIteratorConcept |
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: SinglePassIteratorConcept<Iterator> |
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, DefaultConstructible<Iterator> |
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{ |
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#if BOOST_RANGE_ENABLE_CONCEPT_ASSERT |
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typedef BOOST_DEDUCED_TYPENAME boost::detail::iterator_traits<Iterator>::difference_type difference_type; |
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BOOST_MPL_ASSERT((is_integral<difference_type>)); |
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BOOST_MPL_ASSERT_RELATION(std::numeric_limits<difference_type>::is_signed, ==, true); |
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BOOST_RANGE_CONCEPT_ASSERT(( |
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Convertible< |
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BOOST_DEDUCED_TYPENAME ForwardIteratorConcept::traversal_category, |
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forward_traversal_tag |
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>)); |
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BOOST_CONCEPT_USAGE(ForwardIteratorConcept) |
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{ |
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// See the above note in the SinglePassIteratorConcept about the handling of the |
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// postfix increment. Since with forward and better iterators there is no need |
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// for a proxy, we can sensibly require that the dereference result |
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// is convertible to reference. |
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Iterator i2(i++); |
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boost::ignore_unused_variable_warning(i2); |
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BOOST_DEDUCED_TYPENAME boost::detail::iterator_traits<Iterator>::reference r(*(i++)); |
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boost::ignore_unused_variable_warning(r); |
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} |
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private: |
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Iterator i; |
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#endif |
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}; |
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template<class Iterator> |
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struct BidirectionalIteratorConcept |
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: ForwardIteratorConcept<Iterator> |
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{ |
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#if BOOST_RANGE_ENABLE_CONCEPT_ASSERT |
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BOOST_RANGE_CONCEPT_ASSERT(( |
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Convertible< |
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BOOST_DEDUCED_TYPENAME BidirectionalIteratorConcept::traversal_category, |
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bidirectional_traversal_tag |
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>)); |
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BOOST_CONCEPT_USAGE(BidirectionalIteratorConcept) |
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{ |
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--i; |
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(void)i--; |
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} |
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private: |
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Iterator i; |
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#endif |
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}; |
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template<class Iterator> |
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struct RandomAccessIteratorConcept |
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: BidirectionalIteratorConcept<Iterator> |
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{ |
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#if BOOST_RANGE_ENABLE_CONCEPT_ASSERT |
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BOOST_RANGE_CONCEPT_ASSERT(( |
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Convertible< |
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BOOST_DEDUCED_TYPENAME RandomAccessIteratorConcept::traversal_category, |
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random_access_traversal_tag |
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>)); |
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BOOST_CONCEPT_USAGE(RandomAccessIteratorConcept) |
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{ |
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i += n; |
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i = i + n; |
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i = n + i; |
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i -= n; |
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i = i - n; |
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n = i - j; |
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} |
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private: |
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BOOST_DEDUCED_TYPENAME RandomAccessIteratorConcept::difference_type n; |
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Iterator i; |
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Iterator j; |
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#endif |
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}; |
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} // namespace range_detail |
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//! Check if a type T models the SinglePassRange range concept. |
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template<class T> |
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struct SinglePassRangeConcept |
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{ |
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#if BOOST_RANGE_ENABLE_CONCEPT_ASSERT |
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typedef BOOST_DEDUCED_TYPENAME range_iterator<T const>::type const_iterator; |
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typedef BOOST_DEDUCED_TYPENAME range_iterator<T>::type iterator; |
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BOOST_RANGE_CONCEPT_ASSERT((range_detail::SinglePassIteratorConcept<iterator>)); |
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BOOST_RANGE_CONCEPT_ASSERT((range_detail::SinglePassIteratorConcept<const_iterator>)); |
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BOOST_CONCEPT_USAGE(SinglePassRangeConcept) |
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{ |
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// This has been modified from assigning to this->i |
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// (where i was a member variable) to improve |
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// compatibility with Boost.Lambda |
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iterator i1 = boost::begin(*m_range); |
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iterator i2 = boost::end(*m_range); |
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ignore_unused_variable_warning(i1); |
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ignore_unused_variable_warning(i2); |
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const_constraints(*m_range); |
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} |
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private: |
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void const_constraints(const T& const_range) |
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{ |
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const_iterator ci1 = boost::begin(const_range); |
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const_iterator ci2 = boost::end(const_range); |
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ignore_unused_variable_warning(ci1); |
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ignore_unused_variable_warning(ci2); |
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} |
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// Rationale: |
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// The type of m_range is T* rather than T because it allows |
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// T to be an abstract class. The other obvious alternative of |
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// T& produces a warning on some compilers. |
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T* m_range; |
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#endif |
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}; |
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//! Check if a type T models the ForwardRange range concept. |
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template<class T> |
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struct ForwardRangeConcept : SinglePassRangeConcept<T> |
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{ |
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#if BOOST_RANGE_ENABLE_CONCEPT_ASSERT |
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BOOST_RANGE_CONCEPT_ASSERT((range_detail::ForwardIteratorConcept<BOOST_DEDUCED_TYPENAME ForwardRangeConcept::iterator>)); |
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BOOST_RANGE_CONCEPT_ASSERT((range_detail::ForwardIteratorConcept<BOOST_DEDUCED_TYPENAME ForwardRangeConcept::const_iterator>)); |
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#endif |
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}; |
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template<class Range> |
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struct WriteableRangeConcept |
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{ |
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#if BOOST_RANGE_ENABLE_CONCEPT_ASSERT |
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typedef BOOST_DEDUCED_TYPENAME range_iterator<Range>::type iterator; |
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BOOST_CONCEPT_USAGE(WriteableRangeConcept) |
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{ |
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*i = v; |
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} |
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private: |
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iterator i; |
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BOOST_DEDUCED_TYPENAME range_value<Range>::type v; |
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#endif |
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}; |
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//! Check if a type T models the WriteableForwardRange range concept. |
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template<class T> |
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struct WriteableForwardRangeConcept |
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: ForwardRangeConcept<T> |
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, WriteableRangeConcept<T> |
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{ |
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}; |
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//! Check if a type T models the BidirectionalRange range concept. |
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template<class T> |
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struct BidirectionalRangeConcept : ForwardRangeConcept<T> |
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{ |
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#if BOOST_RANGE_ENABLE_CONCEPT_ASSERT |
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BOOST_RANGE_CONCEPT_ASSERT((BidirectionalIteratorConcept<BOOST_DEDUCED_TYPENAME BidirectionalRangeConcept::iterator>)); |
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BOOST_RANGE_CONCEPT_ASSERT((BidirectionalIteratorConcept<BOOST_DEDUCED_TYPENAME BidirectionalRangeConcept::const_iterator>)); |
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#endif |
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}; |
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//! Check if a type T models the WriteableBidirectionalRange range concept. |
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template<class T> |
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struct WriteableBidirectionalRangeConcept |
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: BidirectionalRangeConcept<T> |
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, WriteableRangeConcept<T> |
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{ |
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}; |
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//! Check if a type T models the RandomAccessRange range concept. |
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template<class T> |
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struct RandomAccessRangeConcept : BidirectionalRangeConcept<T> |
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{ |
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#if BOOST_RANGE_ENABLE_CONCEPT_ASSERT |
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BOOST_RANGE_CONCEPT_ASSERT((RandomAccessIteratorConcept<BOOST_DEDUCED_TYPENAME RandomAccessRangeConcept::iterator>)); |
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BOOST_RANGE_CONCEPT_ASSERT((RandomAccessIteratorConcept<BOOST_DEDUCED_TYPENAME RandomAccessRangeConcept::const_iterator>)); |
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#endif |
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}; |
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//! Check if a type T models the WriteableRandomAccessRange range concept. |
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template<class T> |
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struct WriteableRandomAccessRangeConcept |
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: RandomAccessRangeConcept<T> |
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, WriteableRangeConcept<T> |
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{ |
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}; |
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} // namespace boost |
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#endif // BOOST_RANGE_CONCEPTS_HPP
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