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

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 Ith view in the parent concat_view.

Returns std::get<I>(parent_ ->views_ ).

3) Obtains an iterator to the beginning of the Ith view in the parent concat_view.

Returns ranges::begin(get-view <I>()).

4) Obtains a past-the-end iterator or a sentinel of the Ith 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_ .templateemplace<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_ .templateemplace<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.

If N is sizeof...(Views) - 1, equivalent to get-iter <N>()+= to-underlying-diff-type (steps);.
Otherwise, equivalent to auton_size=ranges::distance(get-view <N>())); if(offset+steps<n_size) get-iter <N>()+= to-underlying-diff-type (steps); else { it_ .templateemplace<N+1>(get-begin <N+1>()); advance-fwd <N+1>(0,offset+steps-n_size); }.

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.

If N is 0, equivalent to get-iter <N>()-= to-underlying-diff-type (steps);.
Otherwise, equivalent to if(offset>=steps) get-iter <N>()-= to-underlying-diff-type (steps); else { autoprev_size=ranges::distance(get-view <N-1>()); it_ .templateemplace<N-1>(get-end <N-1>()); advance-bwd <N-1>(prev_size,steps-offset); }.

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

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