std::ranges::lazy_split_view<V, Pattern>::inner_iterator

 

C++

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Feature test macros (C++20)

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Concepts library (C++20)

Metaprogramming library (C++11)

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General utilities library

Strings library

Containers library

Iterators library

Ranges library (C++20)

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Filesystem library (C++17)

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Technical specifications

Symbols index

External libraries

 

Ranges library

Range access
begin cbegin end cend	rbegin crbegin rend crend	size ssize data cdata	empty
Range conversions
to (C++23)
Range primitives
range_size_trange_difference_t range_value_t	range_reference_trange_const_reference_trange_rvalue_reference_t   (C++23)	iterator_tconst_iterator_tsentinel_t (C++23)
Dangling iterator handling
dangling	borrowed_iterator_t	borrowed_subrange_t
Range concepts
range borrowed_range    sized_range constant_range (C++23)	common_range view viewable_range	input_range output_range forward_range	bidirectional_range random_access_range contiguous_range
Views
view_interface	subrange
Factories
empty_viewviews::empty iota_viewviews::iota	single_viewviews::single basic_istream_viewviews::istream	repeat_viewviews::repeat (C++23)(C++23)
Adaptors
ref_view views::all_tviews::all common_viewviews::common owning_view views::counted reverse_viewviews::reverse zip_viewviews::zip (C++23)(C++23) as_const_viewviews::as_const (C++23)(C++23) as_rvalue_viewviews::as_rvalue (C++23)(C++23)	take_viewviews::take take_while_viewviews::take_while drop_viewviews::drop drop_while_viewviews::drop_while zip_transform_viewviews::zip_transform (C++23)(C++23) adjacent_transform_viewviews::adjacent_transform (C++23)(C++23)   cartesian_product_viewviews::cartesian_product (C++23)(C++23)	elements_viewviews::elements keys_viewviews::keys values_viewviews::values transform_viewviews::transform adjacent_viewviews::adjacent (C++23)(C++23) slide_viewviews::slide (C++23)(C++23) stride_viewviews::stride (C++23)(C++23)	filter_viewviews::filter join_viewviews::join split_viewviews::split lazy_split_viewviews::lazy_split join_with_viewviews::join_with (C++23)(C++23) chunk_viewviews::chunk (C++23)(C++23) chunk_by_viewviews::chunk_by (C++23)(C++23)
Range adaptor objects
Range adaptor closure objects
Helper items
copyable-box	simple-view

 

std::ranges::lazy_split_view

Member functions

lazy_split_view::lazy_split_view (C++20)

lazy_split_view::base (C++20)

lazy_split_view::begin (C++20)

lazy_split_view::end (C++20)

Nested classes

lazy_split_view::outer_iterator (C++20)

lazy_split_view::outer_iterator::value_type (C++20)

lazy_split_view::inner_iterator (C++20)

Deduction guides

 

template< bool Const > struct /*inner_iterator*/;	(1)	(since C++20)

The return type of lazy_split_view::outer_iterator::value_type::begin().

Const matches the template argument of outer_iterator.

The name of this class template (shown here as /*inner_iterator*/) is unspecified.

Member types

Member type	Definition
Base (private)	const V if Const is true, otherwise V. The name is for exposition only.
iterator_concept	equivalent to /*outer_iterator*/<Const>::iterator_concept, that is std::forward_iterator_tag if Base models forward_range, or std::forward_iterator_tag otherwise.
iterator_category	Not present if Base does not model forward_range. std::forward_iterator_tag if std::iterator_traits<ranges::iterator_t<Base>>::iterator_category models std::derived_from<std::forward_iterator_tag>. std::iterator_traits<ranges::iterator_t<Base>>::iterator_category otherwise.
value_type	ranges::range_value_t<Base>.
difference_type	ranges::range_difference_t<Base>.

Data members

Typical implementations of inner_iterator hold two non-static data members:

• An iterator of type /*outer_iterator*/<Const> (shown here as i_ for exposition only) into the underlying view of the parent lazy_split_view.
• A boolean flag (shown here as incremented_ for exposition only) that indicates whether the operator++ was invoked on this object at least once.

Member functions

(constructor) (C++20)	constructs an iterator (public member function)
base (C++20)	returns the underlying iterator (public member function)
operator* (C++20)	returns the current element (public member function)
operator++operator++(int) (C++20)	advances the iterator (public member function)

Member functions

std::ranges::lazy_split_view::inner_iterator::inner_iterator

/*inner_iterator*/() = default;	(1)	(since C++20)
constexpr explicit /*inner_iterator*/( /*outer_iterator*/<Const> i );	(2)	(since C++20)

1) Value initializes the exposition-only data member i_ via its default member initializer (= /*outer_iterator*/<Const>()).

2) Initializes i_ with std::move(i).

The exposition-only data member incremented_ is initialized with its default member initializer to false.

std::ranges::lazy_split_view::inner_iterator::base

constexpr const ranges::iterator_t<Base>& base() const & noexcept;	(1)	(since C++20)
constexpr ranges::iterator_t<Base> base() &&     requires ranges::forward_range<V>;	(2)	(since C++20)

Returns a copy of the underlying iterator.

1) Copy constructs the result from the underlying iterator. Equivalent to return i_./*cur*/();.

2) Move constructs the result from the underlying iterator. Equivalent to return std::move(i_./*cur*/());.

std::ranges::lazy_split_view::inner_iterator::operator*

constexpr decltype(auto) operator*() const;		(since C++20)

Returns the element the underlying iterator points to.

Equivalent to return *i_./*cur*/();.

std::ranges::lazy_split_view::inner_iterator::operator++

constexpr /*inner_iterator*/& operator++();	(1)	(since C++20)
constexpr decltype(auto) operator++(int);	(2)	(since C++20)

1) The function body is equivalent to
incremented_ = true;

if constexpr (!ranges::forward_range<Base>) {
  if constexpr (Pattern::size() == 0) {
    return *this;
  }
}
++i_./*cur*/();

return *this;

2) Equivalent to
if constexpr (ranges::forward_range<Base>) {

  auto tmp = *this;
  ++*this;
  return tmp;
} else {
    ++*this; // no return statement
}

Non-member functions

operator== (C++20)	compares the iterators or the iterator and std::default_sentinel (function)
iter_move (C++20)	casts the result of dereferencing the underlying iterator to its associated rvalue reference type (function)
iter_swap (C++20)	swaps the objects pointed to by two underlying iterators (function)

operator==(std::ranges::split_view::inner_iterator)

friend constexpr bool operator==( const /*inner_iterator*/& x,                                   const /*inner_iterator*/& y )       requires forward_range<Base>;	(1)	(since C++20)
friend constexpr bool operator==( const /*inner_iterator*/& x,                                   std::default_sentinel_t );	(2)	(since C++20)

1) Equivalent to return x.i_./*cur*/() == y.i_./*cur*/();.

2) The function body is equivalent to

auto [pcur, pend] = ranges::subrange{x.i_.parent_->pattern_};
auto end = ranges::end(x.i_.parent_->base_);
if constexpr (/*tiny_range*/<Pattern>) {
  const auto& cur = x.i_./*cur*/();
  if (cur == end) return true;
  if (pcur == pend) return x.incremented_;
  return *cur == *pcur;
} else {
  auto cur = x.i_./*cur*/();
  if (cur == end) return true;
  if (pcur == pend) return x.incremented_;
  do {
    if (*cur != *pcur) return false;
    if (++pcur == pend) return true;
  } while (++cur != end);
  return false;
}

The != operator is synthesized from operator==.

These functions are not visible to ordinary unqualified or qualified lookup, and can only be found by argument-dependent lookup when std::ranges::split_view::inner_iterator is an associated class of the arguments.

iter_move(std::ranges::split_view::inner_iterator)

friend constexpr decltype(auto) iter_move( const /*inner_iterator*/& i )     noexcept(noexcept(ranges::iter_move(i.i_./*cur*/())));		(since C++20)

Equivalent to return ranges::iter_move(i.i_./*cur*/());.

This function is not visible to ordinary unqualified or qualified lookup, and can only be found by argument-dependent lookup when std::ranges::split_view::inner_iterator is an associated class of the arguments.

iter_swap(std::ranges::split_view::inner_iterator)

friend constexpr void iter_swap( const /*inner_iterator*/& x,                                  const /*inner_iterator*/& y )   noexcept(noexcept(ranges::iter_swap(x.i_.current, y.i_.current)))   requires std::indirectly_swappable<ranges::iterator_t<Base>>;		(since C++20)

Equivalent to ranges::iter_swap(x.i_./*cur*/(), y.i_./*cur*/()).

This function is not visible to ordinary unqualified or qualified lookup, and can only be found by argument-dependent lookup when std::ranges::split_view::inner_iterator is an associated class of the arguments.

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR	Applied to	Behavior as published	Correct behavior
LWG 3591	C++20	the && overload of base might invalidate outer iterators	constraints added
LWG 3593	C++20	the const& overload of base returns a reference but might not be noexcept	made noexcept