template < class Iterator , class Value = use_default , class CategoryOrTraversal = use_default , class Reference = use_default , class Difference = use_default > class indirect_iterator { public: typedef /* see below */ value_type; typedef /* see below */ reference; typedef /* see below */ pointer; typedef /* see below */ difference_type; typedef /* see below */ iterator_category; indirect_iterator(); indirect_iterator(Iterator x); template < class Iterator2, class Value2, class Category2 , class Reference2, class Difference2 > indirect_iterator( indirect_iterator< Iterator2, Value2, Category2, Reference2, Difference2 > const& y , typename enable_if_convertible<Iterator2, Iterator>::type* = 0 // exposition ); Iterator const& base() const; reference operator*() const; indirect_iterator& operator++(); indirect_iterator& operator--(); private: Iterator m_iterator; // exposition };
The member types of indirect_iterator are defined according to the following pseudo-code, where V is iterator_traits<Iterator>::value_type
if (Value is use_default) then typedef remove_const<pointee<V>::type>::type value_type; else typedef remove_const<Value>::type value_type; if (Reference is use_default) then if (Value is use_default) then typedef indirect_reference<V>::type reference; else typedef Value& reference; else typedef Reference reference; if (Value is use_default) then typedef pointee<V>::type* pointer; else typedef Value* pointer; if (Difference is use_default) typedef iterator_traits<Iterator>::difference_type difference_type; else typedef Difference difference_type; if (CategoryOrTraversal is use_default) typedef iterator-category ( iterator_traversal<Iterator>::type,``reference``,``value_type`` ) iterator_category; else typedef iterator-category ( CategoryOrTraversal,``reference``,``value_type`` ) iterator_category;
The expression *v, where v is an object of iterator_traits<Iterator>::value_type, shall be valid expression and convertible to reference. Iterator shall model the traversal concept indicated by iterator_category. Value, Reference, and Difference shall be chosen so that value_type, reference, and difference_type meet the requirements indicated by iterator_category.
[Note: there are further requirements on the iterator_traits<Iterator>::value_type if the Value parameter is not use_default, as implied by the algorithm for deducing the default for the value_type member.]
In addition to the concepts indicated by iterator_category and by iterator_traversal<indirect_iterator>::type, a specialization of indirect_iterator models the following concepts, Where v is an object of iterator_traits<Iterator>::value_type:
- Readable Iterator if reference(*v) is convertible to value_type.
- Writable Iterator if reference(*v) = t is a valid expression (where t is an object of type indirect_iterator::value_type)
- Lvalue Iterator if reference is a reference type.
indirect_iterator<X,V1,C1,R1,D1> is interoperable with indirect_iterator<Y,V2,C2,R2,D2> if and only if X is interoperable with Y.
In addition to the operations required by the concepts described above, specializations of indirect_iterator provide the following operations.
indirect_iterator();
Requires: | Iterator must be Default Constructible. |
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Effects: | Constructs an instance of indirect_iterator with a default-constructed m_iterator. |
indirect_iterator(Iterator x);
Effects: | Constructs an instance of indirect_iterator with m_iterator copy constructed from x. |
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template < class Iterator2, class Value2, unsigned Access, class Traversal , class Reference2, class Difference2 > indirect_iterator( indirect_iterator< Iterator2, Value2, Access, Traversal, Reference2, Difference2 > const& y , typename enable_if_convertible<Iterator2, Iterator>::type* = 0 // exposition );
Requires: | Iterator2 is implicitly convertible to Iterator. |
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Effects: | Constructs an instance of indirect_iterator whose m_iterator subobject is constructed from y.base(). |
Iterator const& base() const;
Returns: | m_iterator |
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reference operator*() const;
Returns: | **m_iterator |
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indirect_iterator& operator++();
Effects: | ++m_iterator |
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Returns: | *this |
indirect_iterator& operator--();
Effects: | --m_iterator |
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Returns: | *this |