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94 lines
3.0 KiB
ReStructuredText
94 lines
3.0 KiB
ReStructuredText
::
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template <class UnaryFunction,
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class Iterator,
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class Reference = use_default,
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class Value = use_default>
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class transform_iterator
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: public iterator_adaptor</* see discussion */>
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{
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friend class iterator_core_access;
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public:
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transform_iterator();
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transform_iterator(Iterator const& x, UnaryFunction f);
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template<class OtherIterator, class R2, class V2>
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transform_iterator(
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transform_iterator<UnaryFunction, OtherIterator, R2, V2> const& t
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, typename enable_if_convertible<OtherIterator, Iterator>::type* = 0 // exposition
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);
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UnaryFunction functor() const;
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private:
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typename transform_iterator::value_type dereference() const;
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UnaryFunction m_f;
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};
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``transform_iterator`` requirements
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...................................
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The type ``UnaryFunction`` must be Assignable, Copy Constructible, and
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the expression ``f(*i)`` must be valid where ``f`` is an object of
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type ``UnaryFunction``, ``i`` is an object of type ``Iterator``, and
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where the type of ``f(*i)`` must be
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``result_of<UnaryFunction(iterator_traits<Iterator>::reference)>::type``.
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The type ``Iterator`` must at least model Readable Iterator. The
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resulting ``transform_iterator`` models the most refined of the
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following options that is also modeled by ``Iterator``.
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* Writable Lvalue Iterator if ``result_of<UnaryFunction(iterator_traits<Iterator>::reference)>::type`` is a non-const reference.
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* Readable Lvalue Iterator if ``result_of<UnaryFunction(iterator_traits<Iterator>::reference)>::type`` is a const
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reference.
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* Readable Iterator otherwise.
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The ``transform_iterator`` models the most refined standard traversal
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concept that is modeled by ``Iterator``.
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The ``reference`` type of ``transform_iterator`` is
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``result_of<UnaryFunction(iterator_traits<Iterator>::reference)>::type``.
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The ``value_type`` is ``remove_cv<remove_reference<reference> >::type``.
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``transform_iterator`` public operations
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........................................
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``transform_iterator();``
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:Returns: An instance of ``transform_iterator`` with ``m_f``
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and ``m_iterator`` default constructed.
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``transform_iterator(Iterator const& x, UnaryFunction f);``
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:Returns: An instance of ``transform_iterator`` with ``m_f``
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initialized to ``f`` and ``m_iterator`` initialized to ``x``.
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::
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template<class OtherIterator, class R2, class V2>
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transform_iterator(
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transform_iterator<UnaryFunction, OtherIterator, R2, V2> const& t
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, typename enable_if_convertible<OtherIterator, Iterator>::type* = 0 // exposition
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);
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:Returns: An instance of ``transform_iterator`` that is a copy of ``t``.
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:Requires: ``OtherIterator`` is implicitly convertible to ``Iterator``.
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``UnaryFunction functor() const;``
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:Returns: ``m_f``
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``transform_iterator`` private operations
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.........................................
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``typename transform_iterator::value_type dereference() const;``
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:Returns: ``m_f(transform_iterator::dereference());``
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