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

 

C++

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Named requirements

Feature test macros (C++20)

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Concepts library (C++20)

Metaprogramming library (C++11)

Diagnostics library

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 /*outer_iterator*/;	(1)	(since C++20)

The return type of lazy_split_view::begin, and of lazy_split_view::end when the underlying view is a common_range and forward_range.

If either V or Pattern is not a simple view (e.g. if ranges::iterator_t<const V> is invalid or different from ranges::iterator_t<V>), Const is true for iterators returned from the const overloads, and false otherwise. If V is a simple view, Const is true if and only if V is a forward_range.

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

Member types

Member type	Definition
Parent (private)	const ranges::lazy_split_view if Const is true, otherwise ranges::lazy_split_view. The name is for exposition only.
Base (private)	const V if Const is true, otherwise V. The name is for exposition only.
iterator_concept	std::forward_iterator_tag if Base models forward_range, otherwise std::forward_iterator_tag.
iterator_category	std::input_iterator_tag if Base models forward_range. Not present otherwise.
value_type	ranges::lazy_iterator_view<V, Pattern>::/*outer_iterator*/<Const>::value_type.
difference_type	ranges::range_difference_t<Base>.

Data members

Typical implementations of outer_iterator hold two or three non-static data members:

• A pointer of type Parent* to the parent lazy_split_view object (shown here as parent_ for exposition only).
• An iterator of type ranges::iterator_t<Base> (shown here as current_ for exposition only) into the underlying view; present only if V models forward_range.
• A boolean flag (shown here as trailing_empty_ for exposition only) that indicates whether an empty trailing subrange (if any) was reached.

Member functions

(constructor) (C++20)	constructs an iterator (public member function)
operator* (C++20)	returns the current subrange (public member function)
operator++operator++(int) (C++20)	advances the iterator (public member function)
cur (C++20)	returns conditionally a reference to the current_ (if present) or to the *parent_->current_ (exposition-only member function)

Member functions

std::ranges::lazy_split_view::outer_iterator::outer_iterator

/*outer_iterator*/() = default;	(1)	(since C++20)
constexpr explicit /*outer_iterator*/( Parent& parent )   requires (!ranges::forward_range<Base>);	(2)	(since C++20)
constexpr /*outer_iterator*/( Parent& parent, ranges::iterator_t<Base> current )   requires ranges::forward_range<Base>;	(3)	(since C++20)
constexpr /*outer_iterator*/( /*outer_iterator*/<!Const> i )   requires Const && std::convertible_to<ranges::iterator_t<V>,                                         ranges::iterator_t<Base>>;	(4)	(since C++20)

1) Value initializes the exposition-only non-static data members with their default member initializer, that is:

• parent_ = nullptr;,
• current_ = iterator_t<Base>(); (present only if V models forward_range),

2) Initializes parent_ with std::addressof(parent).

3) Initializes parent_ with std::addressof(parent) and current_ with std::move(current).

4) Initializes parent_ with i.parent_ and current_ with std::move(i.current_).

The exposition-only non-static data member trailing_empty_ is initialized with its default member initializer to false.

std::ranges::lazy_split_view::outer_iterator::operator*

constexpr value_type operator*() const;		(since C++20)

Equivalent to return value_type{*this};.

std::ranges::lazy_split_view::outer_iterator::operator++

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

1) The function body is equivalent to

const auto end = ranges::end(parent_->base_);
  if (/*cur*/() == end) {
    trailing_empty_ = false;
    return *this;
  }
  const auto [pbegin, pend] = ranges::subrange{parent_->pattern_};
  if (pbegin == pend) ++/*cur*/();
  else if constexpr (/*tiny_range*/<Pattern>) {
    /*cur*/() = ranges::find(std::move(/*cur*/()), end, *pbegin);
    if (/*cur*/() != end) {
      ++/*cur*/();
      if (/*cur*/() == end)
        trailing_empty_ = true;
    }
  }
  else {
    do {
      auto [b, p] = ranges::mismatch(/*cur*/(), end, pbegin, pend);
      if (p == pend) {
        /*cur*/() = b;
        if (/*cur*/() == end)
          trailing_empty_ = true;
        break;            // The pattern matched; skip it
      }
    } while (++/*cur*/() != end);
  }
  return *this;

2) Equivalent to

if constexpr (ranges::forward_range<Base>) {
  auto tmp = *this;
  ++*this;
  return tmp;
} else {
  ++*this; // no return statement
}

std::ranges::lazy_split_view::outer_iterator::cur()

constexpr auto& /*cur*/() noexcept;          // exposition only	(1)	(since C++20)
constexpr auto& /*cur*/() const noexcept;    // exposition only	(2)	(since C++20)

This exposition-only convenience member function is referred to from /*outer_iterator*/::operator++(), from the non-member operator==(const /*outer_iterator*/&, std::default_sentinel_t), and from some member functions of the possible implementation of inner_iterator.

1,2) Equivalent to
if constexpr (ranges::forward_range<V>)

    return current_;
  else
    return *parent->current_;

Non-member functions

operator== (C++20)

compares the underlying iterators or the underlying iterator and std::default_sentinel (function)

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

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

1) Equivalent to return x.current_ == y.current_ and x.trailing_empty_ == y.trailing_empty_;.

2) Equivalent to return x./*cur*/() == ranges::end(x.parent_->base_) and !x.trailing_empty_;.

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::outer_iterator is an associated class of the arguments.

Nested classes

value_type (C++20)

the value type of the outer_iterator (public member class)