forked from boostorg/iterator
382 lines
11 KiB
C++
382 lines
11 KiB
C++
// (C) Copyright Jeremy Siek 2002. Permission to copy, use, modify,
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// sell and distribute this software is granted provided this
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// copyright notice appears in all copies. This software is provided
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// "as is" without express or implied warranty, and with no claim as
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// to its suitability for any purpose.
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#ifndef BOOST_ITERATOR_CONCEPTS_HPP
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#define BOOST_ITERATOR_CONCEPTS_HPP
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// Revision History
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// 26 Apr 2003 thw
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// Adapted to new iterator concepts
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// 22 Nov 2002 Thomas Witt
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// Added interoperable concept.
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#include <boost/concept_check.hpp>
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#include <boost/iterator/iterator_categories.hpp>
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// Use boost::detail::iterator_traits to work around some MSVC/Dinkumware problems.
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#include <boost/detail/iterator.hpp>
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#include <boost/type_traits/is_same.hpp>
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#include <boost/type_traits/is_integral.hpp>
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#include <boost/type_traits/is_convertible.hpp>
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#include <boost/mpl/bool.hpp>
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#include <boost/mpl/if.hpp>
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#include <boost/mpl/and.hpp>
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#include <boost/mpl/or.hpp>
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#include <boost/static_assert.hpp>
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// Use boost/limits to work around missing limits headers on some compilers
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#include <boost/limits.hpp>
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#include <algorithm>
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namespace boost_concepts {
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// Used a different namespace here (instead of "boost") so that the
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// concept descriptions do not take for granted the names in
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// namespace boost.
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// We use this in place of STATIC_ASSERT((is_convertible<...>))
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// because some compilers (CWPro7.x) can't detect convertibility.
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//
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// Of course, that just gets us a different error at the moment with
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// some tests, since new iterator category deduction still depends
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// on convertibility detection. We might need some specializations
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// to support this compiler.
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template <class Target, class Source>
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struct static_assert_base_and_derived
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{
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static_assert_base_and_derived(Target* = (Source*)0) {}
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};
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//===========================================================================
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// Iterator Access Concepts
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template <typename Iterator>
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class ReadableIteratorConcept {
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public:
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typedef BOOST_DEDUCED_TYPENAME boost::detail::iterator_traits<Iterator>::value_type value_type;
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typedef BOOST_DEDUCED_TYPENAME boost::detail::iterator_traits<Iterator>::reference reference;
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void constraints() {
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boost::function_requires< boost::SGIAssignableConcept<Iterator> >();
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boost::function_requires< boost::EqualityComparableConcept<Iterator> >();
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boost::function_requires<
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boost::DefaultConstructibleConcept<Iterator> >();
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reference r = *i; // or perhaps read(x)
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value_type v = r;
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value_type v2 = *i;
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boost::ignore_unused_variable_warning(v);
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}
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Iterator i;
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};
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template <
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typename Iterator
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, typename ValueType = typename boost::detail::iterator_traits<Iterator>::value_type
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>
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class WritableIteratorConcept {
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public:
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void constraints() {
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boost::function_requires< boost::SGIAssignableConcept<Iterator> >();
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boost::function_requires< boost::EqualityComparableConcept<Iterator> >();
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boost::function_requires<
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boost::DefaultConstructibleConcept<Iterator> >();
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*i = v; // a good alternative could be something like write(x, v)
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}
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ValueType v;
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Iterator i;
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};
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template <typename Iterator>
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class SwappableIteratorConcept {
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public:
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void constraints() {
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std::iter_swap(i1, i2);
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}
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Iterator i1;
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Iterator i2;
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};
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template <typename Iterator>
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class ReadableLvalueIteratorConcept
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{
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public:
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typedef typename boost::detail::iterator_traits<Iterator>::value_type value_type;
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typedef typename boost::detail::iterator_traits<Iterator>::reference reference;
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void constraints()
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{
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boost::function_requires< ReadableIteratorConcept<Iterator> >();
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typedef boost::mpl::or_<
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boost::is_same<reference, value_type&>
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, boost::is_same<reference, value_type const&>
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> correct_reference;
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BOOST_STATIC_ASSERT(correct_reference::value);
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reference v = *i;
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boost::ignore_unused_variable_warning(v);
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}
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Iterator i;
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};
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template <typename Iterator>
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class WritableLvalueIteratorConcept {
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public:
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typedef typename boost::detail::iterator_traits<Iterator>::value_type value_type;
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typedef typename boost::detail::iterator_traits<Iterator>::reference reference;
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void constraints() {
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boost::function_requires<
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ReadableLvalueIteratorConcept<Iterator> >();
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boost::function_requires<
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WritableIteratorConcept<Iterator, value_type> >();
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boost::function_requires<
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SwappableIteratorConcept<Iterator> >();
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BOOST_STATIC_ASSERT((boost::is_same<reference, value_type&>::value));
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}
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};
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//===========================================================================
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// Iterator Traversal Concepts
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template <typename Iterator>
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class IncrementableIteratorConcept {
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public:
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typedef typename boost::iterator_traversal<Iterator>::type traversal_category;
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void constraints() {
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boost::function_requires< boost::SGIAssignableConcept<Iterator> >();
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boost::function_requires<
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boost::DefaultConstructibleConcept<Iterator> >();
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BOOST_STATIC_ASSERT(
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(boost::is_convertible<
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traversal_category
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, boost::incrementable_traversal_tag
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>::value
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));
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++i;
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(void)i++;
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}
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Iterator i;
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};
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template <typename Iterator>
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class SinglePassIteratorConcept {
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public:
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typedef typename boost::iterator_traversal<Iterator>::type traversal_category;
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typedef typename boost::detail::iterator_traits<Iterator>::difference_type difference_type;
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void constraints() {
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boost::function_requires< IncrementableIteratorConcept<Iterator> >();
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boost::function_requires< boost::EqualityComparableConcept<Iterator> >();
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BOOST_STATIC_ASSERT(
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(boost::is_convertible<
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traversal_category
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, boost::single_pass_traversal_tag
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>::value
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));
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}
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};
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template <typename Iterator>
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class ForwardTraversalConcept {
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public:
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typedef typename boost::iterator_traversal<Iterator>::type traversal_category;
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typedef typename boost::detail::iterator_traits<Iterator>::difference_type difference_type;
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void constraints() {
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boost::function_requires< SinglePassIteratorConcept<Iterator> >();
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typedef boost::mpl::and_<
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boost::is_integral<difference_type>,
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boost::mpl::bool_< std::numeric_limits<difference_type>::is_signed >
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> difference_type_is_signed_integral;
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BOOST_STATIC_ASSERT(difference_type_is_signed_integral::value);
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BOOST_STATIC_ASSERT(
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(boost::is_convertible<
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traversal_category
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, boost::forward_traversal_tag
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>::value
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));
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}
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};
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template <typename Iterator>
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class BidirectionalTraversalConcept {
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public:
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typedef typename boost::iterator_traversal<Iterator>::type traversal_category;
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void constraints() {
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boost::function_requires< ForwardTraversalConcept<Iterator> >();
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BOOST_STATIC_ASSERT(
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(boost::is_convertible<
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traversal_category
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, boost::bidirectional_traversal_tag
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>::value
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));
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--i;
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(void)i--;
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}
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Iterator i;
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};
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template <typename Iterator>
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class RandomAccessTraversalConcept {
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public:
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typedef typename boost::iterator_traversal<Iterator>::type traversal_category;
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typedef typename boost::detail::iterator_traits<Iterator>::difference_type
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difference_type;
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void constraints() {
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boost::function_requires< BidirectionalTraversalConcept<Iterator> >();
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BOOST_STATIC_ASSERT(
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(boost::is_convertible<
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traversal_category
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, boost::random_access_traversal_tag
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>::value
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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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difference_type n;
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Iterator i, j;
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};
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//===========================================================================
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// Iterator Interoperability Concept
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namespace detail
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{
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template <typename TraversalTag>
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struct Operations;
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template <>
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struct Operations<boost::incrementable_traversal_tag>
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{
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template <typename Iterator1, typename Iterator2>
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static void constraints(Iterator1 const& i1, Iterator2 const& i2)
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{
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// no interoperability constraints
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}
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};
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template <>
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struct Operations<boost::single_pass_traversal_tag>
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{
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template <typename Iterator1, typename Iterator2>
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static void constraints(Iterator1 const& i1, Iterator2 const& i2)
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{
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Operations<boost::incrementable_traversal_tag>::constraints(i1, i2);
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i1 == i2;
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i1 != i2;
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i2 == i1;
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i2 != i1;
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}
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};
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template <>
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struct Operations<boost::forward_traversal_tag>
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{
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template <typename Iterator1, typename Iterator2>
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static void constraints(Iterator1 const& i1, Iterator2 const& i2)
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{
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Operations<boost::single_pass_traversal_tag>::constraints(i1, i2);
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}
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};
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template <>
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struct Operations<boost::bidirectional_traversal_tag>
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{
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template <typename Iterator1, typename Iterator2>
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static void constraints(Iterator1 const& i1, Iterator2 const& i2)
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{
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Operations<boost::forward_traversal_tag>::constraints(i1, i2);
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}
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};
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template <>
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struct Operations<boost::random_access_traversal_tag>
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{
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template <typename Iterator1, typename Iterator2>
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static void constraints(Iterator1 const& i1, Iterator2 const& i2)
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{
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Operations<boost::bidirectional_traversal_tag>::constraints(i1, i2);
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i1 < i2;
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i1 <= i2;
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i1 > i2;
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i1 >= i2;
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i1 - i2;
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i2 < i1;
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i2 <= i1;
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i2 > i1;
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i2 >= i1;
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i2 - i1;
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}
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};
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} // namespace detail
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template <typename Iterator, typename ConstIterator>
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class InteroperableConcept
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{
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public:
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typedef typename boost::iterator_traversal<Iterator>::type traversal_category;
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typedef typename boost::detail::iterator_traits<Iterator>::difference_type
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difference_type;
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typedef typename boost::iterator_traversal<ConstIterator>::type
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const_traversal_category;
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typedef typename boost::detail::iterator_traits<ConstIterator>::difference_type
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const_difference_type;
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void constraints() {
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BOOST_STATIC_ASSERT((boost::is_same< difference_type,
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const_difference_type>::value));
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BOOST_STATIC_ASSERT((boost::is_same< traversal_category,
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const_traversal_category>::value));
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// ToDo check what the std really requires
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// detail::Operations<traversal_category>::constraints(i, ci);
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ci = i;
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}
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Iterator i;
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ConstIterator ci;
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};
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} // namespace boost_concepts
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#endif // BOOST_ITERATOR_CONCEPTS_HPP
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