From Jason Turner

[range.split.outer]

C++17 → C++20 4.1 KB 128 lines
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Archived: C++17 | C++20
Markdown: C++17 | C++20
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tmp/tmp9tff2tpu/{from.md → to.md} RENAMED
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+ #### Class template `split_view::outer-iterator` <a id="range.split.outer">[[range.split.outer]]</a>
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+
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+ ``` cpp
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+ namespace std::ranges {
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+ template<input_range V, forward_range Pattern>
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+ requires view<V> && view<Pattern> &&
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+ indirectly_comparable<iterator_t<V>, iterator_t<Pattern>, ranges::equal_to> &&
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+ (forward_range<V> || tiny-range<Pattern>)
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+ template<bool Const>
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+ struct split_view<V, Pattern>::outer-iterator {
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+ private:
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+ using Parent = // exposition only
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+ conditional_t<Const, const split_view, split_view>;
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+ using Base = // exposition only
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+ conditional_t<Const, const V, V>;
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+ Parent* parent_ = nullptr; // exposition only
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+ iterator_t<Base> current_ = // exposition only, present only if V models forward_range
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+ iterator_t<Base>();
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+
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+ public:
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+ using iterator_concept =
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+ conditional_t<forward_range<Base>, forward_iterator_tag, input_iterator_tag>;
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+ using iterator_category = input_iterator_tag;
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+ // [range.split.outer.value], class split_view::outer-iterator::value_type
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+ struct value_type;
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+ using difference_type = range_difference_t<Base>;
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+
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+ outer-iterator() = default;
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+ constexpr explicit outer-iterator(Parent& parent)
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+ requires (!forward_range<Base>);
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+ constexpr outer-iterator(Parent& parent, iterator_t<Base> current)
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+ requires forward_range<Base>;
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+ constexpr outer-iterator(outer-iterator<!Const> i)
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+ requires Const && convertible_to<iterator_t<V>, iterator_t<Base>>;
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+
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+ constexpr value_type operator*() const;
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+
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+ constexpr outer-iterator& operator++();
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+ constexpr decltype(auto) operator++(int) {
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+ if constexpr (forward_range<Base>) {
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+ auto tmp = *this;
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+ ++*this;
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+ return tmp;
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+ } else
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+ ++*this;
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+ }
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+
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+ friend constexpr bool operator==(const outer-iterator& x, const outer-iterator& y)
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+ requires forward_range<Base>;
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+
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+ friend constexpr bool operator==(const outer-iterator& x, default_sentinel_t);
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+ };
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+ }
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+ ```
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+
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+ Many of the following specifications refer to the notional member
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+ *current* of *`outer-iterator`*. *current* is equivalent to *`current_`*
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+ if `V` models `forward_range`, and `parent_->current_` otherwise.
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+
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+ ``` cpp
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+ constexpr explicit outer-iterator(Parent& parent)
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+ requires (!forward_range<Base>);
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+ ```
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+
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+ *Effects:* Initializes *parent\_* with `addressof(parent)`.
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+
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+ ``` cpp
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+ constexpr outer-iterator(Parent& parent, iterator_t<Base> current)
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+ requires forward_range<Base>;
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+ ```
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+
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+ *Effects:* Initializes *parent\_* with `addressof(parent)` and
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+ *current\_* with `std::move(current)`.
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+
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+ ``` cpp
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+ constexpr outer-iterator(outer-iterator<!Const> i)
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+ requires Const && convertible_to<iterator_t<V>, iterator_t<Base>>;
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+ ```
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+
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+ *Effects:* Initializes *parent\_* with `i.`*`parent_`* and *current\_*
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+ with `std::move(i.`*`current_`*`)`.
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+
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+ ``` cpp
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+ constexpr value_type operator*() const;
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+ ```
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+
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+ *Effects:* Equivalent to: `return value_type{*this};`
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+
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+ ``` cpp
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+ constexpr outer-iterator& operator++();
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+ ```
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+
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+ *Effects:* Equivalent to:
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+
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+ ``` cpp
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+ const auto end = ranges::end(parent_->base_);
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+ if (current == end) return *this;
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+ const auto [pbegin, pend] = subrange{parent_->pattern_};
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+ if (pbegin == pend) ++current;
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+ else {
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+ do {
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+ auto [b, p] = ranges::mismatch(std::move(current), end, pbegin, pend);
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+ current = std::move(b);
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+ if (p == pend) {
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+ break; // The pattern matched; skip it
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+ }
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+ } while (++current != end);
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+ }
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+ return *this;
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+ ```
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+
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+ ``` cpp
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+ friend constexpr bool operator==(const outer-iterator& x, const outer-iterator& y)
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+ requires forward_range<Base>;
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+ ```
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+
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+ *Effects:* Equivalent to: `return x.`*`current_`*` == y.`*`current_`*`;`
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+
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+ ``` cpp
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+ friend constexpr bool operator==(const outer-iterator& x, default_sentinel_t);
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+ ```
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+
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+ *Effects:* Equivalent to:
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+ `return x.`*`current`*` == ranges::end(x.`*`parent_`*`->`*`base_`*`);`
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+