142 lines
4.5 KiB
ReStructuredText
142 lines
4.5 KiB
ReStructuredText
.. Copyright David Abrahams 2006. Distributed under the Boost
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.. Software License, Version 1.0. (See accompanying
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.. file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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::
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template <class Iterator>
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class reverse_iterator
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{
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public:
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typedef iterator_traits<Iterator>::value_type value_type;
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typedef iterator_traits<Iterator>::reference reference;
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typedef iterator_traits<Iterator>::pointer pointer;
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typedef iterator_traits<Iterator>::difference_type difference_type;
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typedef /* see below */ iterator_category;
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reverse_iterator() {}
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explicit reverse_iterator(Iterator x) ;
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template<class OtherIterator>
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reverse_iterator(
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reverse_iterator<OtherIterator> const& r
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, typename enable_if_convertible<OtherIterator, Iterator>::type* = 0 // exposition
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);
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Iterator const& base() const;
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reference operator*() const;
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reverse_iterator& operator++();
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reverse_iterator& operator--();
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private:
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Iterator m_iterator; // exposition
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};
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If ``Iterator`` models Random Access Traversal Iterator and Readable
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Lvalue Iterator, then ``iterator_category`` is convertible to
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``random_access_iterator_tag``. Otherwise, if
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``Iterator`` models Bidirectional Traversal Iterator and Readable
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Lvalue Iterator, then ``iterator_category`` is convertible to
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``bidirectional_iterator_tag``. Otherwise, ``iterator_category`` is
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convertible to ``input_iterator_tag``.
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``reverse_iterator`` requirements
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.................................
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``Iterator`` must be a model of Bidirectional Traversal Iterator. The
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type ``iterator_traits<Iterator>::reference`` must be the type of
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``*i``, where ``i`` is an object of type ``Iterator``.
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``reverse_iterator`` models
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...........................
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A specialization of ``reverse_iterator`` models the same iterator
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traversal and iterator access concepts modeled by its ``Iterator``
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argument. In addition, it may model old iterator concepts
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specified in the following table:
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+---------------------------------------+-----------------------------------+
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| If ``I`` models |then ``reverse_iterator<I>`` models|
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+=======================================+===================================+
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| Readable Lvalue Iterator, | Bidirectional Iterator |
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| Bidirectional Traversal Iterator | |
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+---------------------------------------+-----------------------------------+
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| Writable Lvalue Iterator, | Mutable Bidirectional Iterator |
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| Bidirectional Traversal Iterator | |
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+---------------------------------------+-----------------------------------+
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| Readable Lvalue Iterator, | Random Access Iterator |
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| Random Access Traversal Iterator | |
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+---------------------------------------+-----------------------------------+
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| Writable Lvalue Iterator, | Mutable Random Access Iterator |
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| Random Access Traversal Iterator | |
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+---------------------------------------+-----------------------------------+
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``reverse_iterator<X>`` is interoperable with
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``reverse_iterator<Y>`` if and only if ``X`` is interoperable with
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``Y``.
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``reverse_iterator`` operations
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...............................
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In addition to the operations required by the concepts modeled by
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``reverse_iterator``, ``reverse_iterator`` provides the following
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operations.
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``reverse_iterator();``
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:Requires: ``Iterator`` must be Default Constructible.
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:Effects: Constructs an instance of ``reverse_iterator`` with ``m_iterator``
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default constructed.
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``explicit reverse_iterator(Iterator x);``
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:Effects: Constructs an instance of ``reverse_iterator`` with
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``m_iterator`` copy constructed from ``x``.
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::
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template<class OtherIterator>
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reverse_iterator(
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reverse_iterator<OtherIterator> const& r
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, typename enable_if_convertible<OtherIterator, Iterator>::type* = 0 // exposition
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);
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:Requires: ``OtherIterator`` is implicitly convertible to ``Iterator``.
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:Effects: Constructs instance of ``reverse_iterator`` whose
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``m_iterator`` subobject is constructed from ``y.base()``.
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``Iterator const& base() const;``
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:Returns: ``m_iterator``
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``reference operator*() const;``
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:Effects:
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::
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Iterator tmp = m_iterator;
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return *--tmp;
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``reverse_iterator& operator++();``
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:Effects: ``--m_iterator``
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:Returns: ``*this``
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``reverse_iterator& operator--();``
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:Effects: ``++m_iterator``
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:Returns: ``*this``
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