libstdc++
std::reverse_iterator< _Iterator > Class Template Reference

#include <stl_iterator.h>

Inheritance diagram for std::reverse_iterator< _Iterator >:
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Public Types

using difference_type = iter_difference_t< _Iterator >
 
using iterator_category = __detail::__clamp_iter_cat< typename __traits_type::iterator_category, random_access_iterator_tag >
 
using iterator_concept = __conditional_t< random_access_iterator< _Iterator >, random_access_iterator_tag, bidirectional_iterator_tag >
 
typedef _Iterator iterator_type
 
typedef __traits_type::pointer pointer
 
using reference = iter_reference_t< _Iterator >
 
using value_type = iter_value_t< _Iterator >
 

Public Member Functions

constexpr reverse_iterator () noexcept(/*conditional */)
 
constexpr reverse_iterator (const reverse_iterator &__x) noexcept(/*conditional */)
 
template<typename _Iter >
requires __convertible<_Iter>
constexpr reverse_iterator (const reverse_iterator< _Iter > &__x) noexcept(/*conditional */)
 
constexpr reverse_iterator (iterator_type __x) noexcept(/*conditional */)
 
constexpr iterator_type base () const noexcept(/*conditional */)
 
constexpr reference operator* () const
 
constexpr reverse_iterator operator+ (difference_type __n) const
 
constexpr reverse_iteratoroperator++ ()
 
constexpr reverse_iterator operator++ (int)
 
constexpr reverse_iteratoroperator+= (difference_type __n)
 
constexpr reverse_iterator operator- (difference_type __n) const
 
constexpr reverse_iteratoroperator-- ()
 
constexpr reverse_iterator operator-- (int)
 
constexpr reverse_iteratoroperator-= (difference_type __n)
 
constexpr pointer operator-> () const
 
reverse_iteratoroperator= (const reverse_iterator &)=default
 
template<typename _Iter >
requires __convertible<_Iter> && assignable_from<_Iterator&, const _Iter&>
constexpr reverse_iteratoroperator= (const reverse_iterator< _Iter > &__x) noexcept(/*conditional */)
 
constexpr reference operator[] (difference_type __n) const
 

Protected Types

typedef iterator_traits< _Iterator > __traits_type
 

Protected Attributes

_Iterator current
 

Friends

constexpr iter_rvalue_reference_t< _Iterator > iter_move (const reverse_iterator &__i) noexcept(is_nothrow_copy_constructible_v< _Iterator > &&noexcept(ranges::iter_move(--std::declval< _Iterator & >())))
 
template<indirectly_swappable< _Iterator > _Iter2>
constexpr void iter_swap (const reverse_iterator &__x, const reverse_iterator< _Iter2 > &__y) noexcept(is_nothrow_copy_constructible_v< _Iterator > &&is_nothrow_copy_constructible_v< _Iter2 > &&noexcept(ranges::iter_swap(--std::declval< _Iterator & >(), --std::declval< _Iter2 & >())))
 

Detailed Description

template<typename _Iterator>
class std::reverse_iterator< _Iterator >

Bidirectional and random access iterators have corresponding reverse iterator adaptors that iterate through the data structure in the opposite direction. They have the same signatures as the corresponding iterators. The fundamental relation between a reverse iterator and its corresponding iterator i is established by the identity:

This mapping is dictated by the fact that while there is always a pointer past the end of an array, there might not be a valid pointer before the beginning of an array. [24.4.1]/1,2

Reverse iterators can be tricky and surprising at first. Their semantics make sense, however, and the trickiness is a side effect of the requirement that the iterators must be safe.

Definition at line 136 of file bits/stl_iterator.h.

Member Typedef Documentation

◆ __traits_type

template<typename _Iterator >
typedef iterator_traits<_Iterator> std::reverse_iterator< _Iterator >::__traits_type
protected

Definition at line 157 of file bits/stl_iterator.h.

◆ difference_type

template<typename _Iterator >
using std::reverse_iterator< _Iterator >::difference_type = iter_difference_t<_Iterator>

Definition at line 174 of file bits/stl_iterator.h.

◆ iterator_category

template<typename _Iterator >
using std::reverse_iterator< _Iterator >::iterator_category = __detail::__clamp_iter_cat<typename __traits_type::iterator_category, random_access_iterator_tag>

Definition at line 170 of file bits/stl_iterator.h.

◆ iterator_concept

template<typename _Iterator >
using std::reverse_iterator< _Iterator >::iterator_concept = __conditional_t<random_access_iterator<_Iterator>, random_access_iterator_tag, bidirectional_iterator_tag>

Definition at line 166 of file bits/stl_iterator.h.

◆ iterator_type

template<typename _Iterator >
typedef _Iterator std::reverse_iterator< _Iterator >::iterator_type

Definition at line 160 of file bits/stl_iterator.h.

◆ pointer

template<typename _Iterator >
typedef __traits_type::pointer std::reverse_iterator< _Iterator >::pointer

Definition at line 161 of file bits/stl_iterator.h.

◆ reference

template<typename _Iterator >
using std::reverse_iterator< _Iterator >::reference = iter_reference_t<_Iterator>

Definition at line 175 of file bits/stl_iterator.h.

◆ value_type

template<typename _Iterator >
using std::reverse_iterator< _Iterator >::value_type = iter_value_t<_Iterator>

Definition at line 173 of file bits/stl_iterator.h.

Constructor & Destructor Documentation

◆ reverse_iterator() [1/4]

template<typename _Iterator >
constexpr std::reverse_iterator< _Iterator >::reverse_iterator ( )
inlineconstexprnoexcept

The default constructor value-initializes member current. If it is a pointer, that means it is zero-initialized.

Definition at line 186 of file bits/stl_iterator.h.

◆ reverse_iterator() [2/4]

template<typename _Iterator >
constexpr std::reverse_iterator< _Iterator >::reverse_iterator ( iterator_type  __x)
inlineexplicitconstexprnoexcept

This iterator will move in the opposite direction that x does.

Definition at line 195 of file bits/stl_iterator.h.

◆ reverse_iterator() [3/4]

template<typename _Iterator >
constexpr std::reverse_iterator< _Iterator >::reverse_iterator ( const reverse_iterator< _Iterator > &  __x)
inlineconstexprnoexcept

The copy constructor is normal.

Definition at line 204 of file bits/stl_iterator.h.

◆ reverse_iterator() [4/4]

template<typename _Iterator >
template<typename _Iter >
requires __convertible<_Iter>
constexpr std::reverse_iterator< _Iterator >::reverse_iterator ( const reverse_iterator< _Iter > &  __x)
inlineconstexprnoexcept

A reverse_iterator across other types can be copied if the underlying iterator can be converted to the type of current.

Definition at line 222 of file bits/stl_iterator.h.

Member Function Documentation

◆ base()

template<typename _Iterator >
constexpr iterator_type std::reverse_iterator< _Iterator >::base ( ) const
inlineconstexprnoexcept
Returns
current, the iterator used for underlying work.

Definition at line 248 of file bits/stl_iterator.h.

Referenced by std::operator==().

◆ operator*()

template<typename _Iterator >
constexpr reference std::reverse_iterator< _Iterator >::operator* ( ) const
inlineconstexpr
Returns
A reference to the value at --current

This requires that --current is dereferenceable.

Warning
This implementation requires that for an iterator of the underlying iterator type, x, a reference obtained by *x remains valid after x has been modified or destroyed. This is a bug: http://gcc.gnu.org/PR51823

Definition at line 264 of file bits/stl_iterator.h.

◆ operator+()

template<typename _Iterator >
constexpr reverse_iterator std::reverse_iterator< _Iterator >::operator+ ( difference_type  __n) const
inlineconstexpr
Returns
A reverse_iterator that refers to current - __n

The underlying iterator must be a Random Access Iterator.

Definition at line 347 of file bits/stl_iterator.h.

◆ operator++() [1/2]

template<typename _Iterator >
constexpr reverse_iterator & std::reverse_iterator< _Iterator >::operator++ ( )
inlineconstexpr
Returns
*this

Decrements the underlying iterator.

Definition at line 296 of file bits/stl_iterator.h.

◆ operator++() [2/2]

template<typename _Iterator >
constexpr reverse_iterator std::reverse_iterator< _Iterator >::operator++ ( int  )
inlineconstexpr
Returns
The original value of *this

Decrements the underlying iterator.

Definition at line 308 of file bits/stl_iterator.h.

◆ operator+=()

template<typename _Iterator >
constexpr reverse_iterator & std::reverse_iterator< _Iterator >::operator+= ( difference_type  __n)
inlineconstexpr
Returns
*this

Moves the underlying iterator backwards __n steps. The underlying iterator must be a Random Access Iterator.

Definition at line 357 of file bits/stl_iterator.h.

◆ operator-()

template<typename _Iterator >
constexpr reverse_iterator std::reverse_iterator< _Iterator >::operator- ( difference_type  __n) const
inlineconstexpr
Returns
A reverse_iterator that refers to current - __n

The underlying iterator must be a Random Access Iterator.

Definition at line 370 of file bits/stl_iterator.h.

◆ operator--() [1/2]

template<typename _Iterator >
constexpr reverse_iterator & std::reverse_iterator< _Iterator >::operator-- ( )
inlineconstexpr
Returns
*this

Increments the underlying iterator.

Definition at line 321 of file bits/stl_iterator.h.

◆ operator--() [2/2]

template<typename _Iterator >
constexpr reverse_iterator std::reverse_iterator< _Iterator >::operator-- ( int  )
inlineconstexpr
Returns
A reverse_iterator with the previous value of *this

Increments the underlying iterator.

Definition at line 333 of file bits/stl_iterator.h.

◆ operator-=()

template<typename _Iterator >
constexpr reverse_iterator & std::reverse_iterator< _Iterator >::operator-= ( difference_type  __n)
inlineconstexpr
Returns
*this

Moves the underlying iterator forwards __n steps. The underlying iterator must be a Random Access Iterator.

Definition at line 380 of file bits/stl_iterator.h.

◆ operator->()

template<typename _Iterator >
constexpr pointer std::reverse_iterator< _Iterator >::operator-> ( ) const
inlineconstexpr
Returns
A pointer to the value at --current

This requires that --current is dereferenceable.

Definition at line 277 of file bits/stl_iterator.h.

◆ operator=()

template<typename _Iterator >
template<typename _Iter >
requires __convertible<_Iter> && assignable_from<_Iterator&, const _Iter&>
constexpr reverse_iterator & std::reverse_iterator< _Iterator >::operator= ( const reverse_iterator< _Iter > &  __x)
inlineconstexprnoexcept

Definition at line 235 of file bits/stl_iterator.h.

◆ operator[]()

template<typename _Iterator >
constexpr reference std::reverse_iterator< _Iterator >::operator[] ( difference_type  __n) const
inlineconstexpr
Returns
The value at current - __n - 1

The underlying iterator must be a Random Access Iterator.

Definition at line 393 of file bits/stl_iterator.h.

Friends And Related Symbol Documentation

◆ reverse_iterator

template<typename _Iterator >
template<typename _Iter >
friend class reverse_iterator
friend

Definition at line 144 of file bits/stl_iterator.h.

◆ iter_move

template<typename _Iterator >
constexpr iter_rvalue_reference_t< _Iterator > iter_move ( const reverse_iterator< _Iterator > &  __i)
friend

Definition at line 399 of file bits/stl_iterator.h.

◆ iter_swap

template<typename _Iterator >
template<indirectly_swappable< _Iterator > _Iter2>
constexpr void iter_swap ( const reverse_iterator< _Iterator > &  __x,
const reverse_iterator< _Iter2 > &  __y 
)
friend

Definition at line 409 of file bits/stl_iterator.h.

Member Data Documentation

◆ current

template<typename _Iterator >
_Iterator std::reverse_iterator< _Iterator >::current
protected

Definition at line 155 of file bits/stl_iterator.h.


The documentation for this class was generated from the following file: