367 lines
13 KiB
C++
367 lines
13 KiB
C++
// 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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