std::ranges::concat_view<Views...>:: iterator <Const>:: satisfy , prev , advance-fwd , advance-bwd

From cppreference.com
C++
Ranges library
Range adaptors
std::ranges::concat_view
Member functions
Deduction guides
Iterator
Member functions
concat_view:: iterator :: satisfy
concat_view:: iterator :: prev
concat_view:: iterator :: advance-fwd
concat_view:: iterator :: advance-bwd
Non-member functions

The following exposition-only member function templates simplify the description.

Each helper function template has a non-type template parameter of type std::size_t .

  • If the name of the template parameter is N , the template argument is always it_  . index ( ) .
  • If the name of the template parameter is I , the template argument can be any std::size_t value in [ ​ 0 ​ , sizeof... ( Views ) ) .

However, the template argument might not be a compile-time constant, therefore the actual effect of helper  < non_const > ( /* arguments */ ) is similar to if ( non_const == 0 )
helper  < 0 > ( /* arguments */ ) ;
else if ( non_const == 1 )
helper  < 1 > ( /* arguments */ ) ;
/* other indices */
else if ( non_const == ( sizeof... ( Views ) - 1 ) )
helper  < sizeof... ( Views ) - 1 > ( /* arguments */ ) ;
.

Helper templates

Mini helper templates

template < std:: size_t N >
constexpr auto /*get-iter*/ ( ) ;
(1) ( exposition only* )
template < std:: size_t I >
constexpr auto /*get-view*/ ( ) ;
(2) ( exposition only* )
template < std:: size_t I >
constexpr auto /*get-begin*/ ( ) ;
(3) ( exposition only* )
template < std:: size_t I >
constexpr auto /*get-end*/ ( ) ;
(4) ( exposition only* )
template < std:: size_t N >
constexpr auto /*to-underlying-diff-type*/ ( difference_type value ) ;
(5) ( exposition only* )

The mini helper templates simplify the description of the main helper templates and member functions. They are not included in the C++ standard documents.

1) Obtains the underlying iterator contained in it_ .
Returns std::get < N > ( it_  ) .
2) Obtains the I th view in the parent concat_view .
Returns std::get < I > ( parent_  - > views_  ) .
3) Obtains an iterator to the beginning of the I th view in the parent concat_view .
Returns ranges:: begin ( get-view  < I > ( ) ) .
4) Obtains a past-the-end iterator or a sentinel of the I th view in the parent concat_view .
Returns ranges:: end ( get-view  < I > ( ) ) .
5) Converts value to the underlying difference type of the underlying iterator contained in it_ .
Returns static_cast < std:: iter_difference_t < std:: variant_alternative_t < N, base-iter  >>> ( value ) .

std::ranges::concat_view:: iterator :: satisfy <N>

template < std:: size_t N >
constexpr void /*satisfy*/ ( ) ;
( exposition only* )

Adjusts the current (global) position of it_ .

  • If N is sizeof... ( Views ) - 1 , does nothing.
  • Otherwise, equivalent to if ( get-iter  < N > ( ) == get-end  < N > ( ) )
    {
    it_  . template emplace < N + 1 > ( get-begin  < N + 1 > ( ) ) ;
    satisfy  < N + 1 > ( ) ;
    }     .

std::ranges::concat_view:: iterator :: prev <N>

template < size_t N >
constexpr void /*prev*/ ( ) ;
( exposition only* )

Moves it_ to the previous (global) position.

  • If N is ​ 0 ​ , equivalent to -- get-iter  < 0 > ( ) ; .
  • Otherwise, equivalent to if ( get-iter  < N > ( ) == get-begin  < N > ( ) )
    {
    it_  . template emplace < N - 1 > ( get-end  < N - 1 > ( ) ) ;
    prev  < N - 1 > ( ) ;
    }
    else
    -- get-iter  < 0 > ( ) ;     .

std::ranges::concat_view:: iterator :: advance-fwd <N>

template < size_t N >

constexpr void /*advance-fwd*/ ( difference_type offset,

difference_type steps ) ;
( exposition only* )

Advances the current (global) position step steps forward.

Parameters

offset - the offset of the current (global) position from the beginning of range it_ currently refers into
steps - the number of steps to advance forward

std::ranges::concat_view:: iterator :: advance-bwd <N>

template < size_t N >

constexpr void /*advance-bwd*/ ( difference_type offset,

difference_type steps ) ;
( exposition only* )

Advances the current (global) position steps steps backward.

Parameters

offset - the offset of the current (global) position from the beginning of range it_ currently refers into
steps - the number of steps to advance backward
Retrieved from " https://en.cppreference.com/mwiki/index.php?title=cpp/ranges/concat_view/iterator/helpers&oldid=176986 "