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. |
|---|---|
| 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. |
|---|
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. |
|---|---|
| Effects: | Constructs an instance of indirect_iterator whose m_iterator subobject is constructed from y.base(). |
Iterator const& base() const;
| Returns: | m_iterator |
|---|
reference operator*() const;
| Returns: | **m_iterator |
|---|
indirect_iterator& operator++();
| Effects: | ++m_iterator |
|---|---|
| Returns: | *this |
indirect_iterator& operator--();
| Effects: | --m_iterator |
|---|---|
| Returns: | *this |