From Jason Turner

[range.split.inner]

C++17 → C++20 4.0 KB 128 lines
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Archived: C++17 | C++20
Markdown: C++17 | C++20
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  1. tmp/tmpzwubo58h/{from.md → to.md} +125 -0
tmp/tmpzwubo58h/{from.md → to.md} RENAMED
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+ #### Class template `split_view::inner-iterator` <a id="range.split.inner">[[range.split.inner]]</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>::inner-iterator {
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+ private:
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+ using Base = conditional_t<Const, const V, V>; // exposition only
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+ outer-iterator<Const> i_ = outer-iterator<Const>(); // exposition only
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+ bool incremented_ = false; // exposition only
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+ public:
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+ using iterator_concept = typename outer-iterator<Const>::iterator_concept;
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+ using iterator_category = see below;
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+ using value_type = range_value_t<Base>;
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+ using difference_type = range_difference_t<Base>;
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+
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+ inner-iterator() = default;
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+ constexpr explicit inner-iterator(outer-iterator<Const> i);
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+
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+ constexpr decltype(auto) operator*() const { return *i_.current; }
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+
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+ constexpr inner-iterator& operator++();
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+ constexpr decltype(auto) operator++(int) {
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+ if constexpr (forward_range<V>) {
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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 inner-iterator& x, const inner-iterator& y)
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+ requires forward_range<Base>;
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+
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+ friend constexpr bool operator==(const inner-iterator& x, default_sentinel_t);
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+
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+ friend constexpr decltype(auto) iter_move(const inner-iterator& i)
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+ noexcept(noexcept(ranges::iter_move(i.i_.current))) {
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+ return ranges::iter_move(i.i_.current);
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+ }
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+
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+ friend constexpr void iter_swap(const inner-iterator& x, const inner-iterator& y)
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+ noexcept(noexcept(ranges::iter_swap(x.i_.current, y.i_.current)))
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+ requires indirectly_swappable<iterator_t<Base>>;
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+ };
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+ }
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+ ```
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+
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+ The *typedef-name* `iterator_category` denotes:
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+
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+ - `forward_iterator_tag` if
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+ `iterator_traits<iterator_t<Base>>::iterator_category` models
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+ `derived_from<forward_iterator_tag>`;
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+ - otherwise, `iterator_traits<iterator_t<Base>>::iterator_category`.
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+
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+ ``` cpp
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+ constexpr explicit inner-iterator(outer-iterator<Const> i);
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+ ```
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+
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+ *Effects:* Initializes *i\_* with `std::move(i)`.
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+
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+ ``` cpp
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+ constexpr inner-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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+ incremented_ = true;
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+ if constexpr (!forward_range<Base>) {
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+ if constexpr (Pattern::size() == 0) {
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+ return *this;
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+ }
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+ }
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+ ++i_.current;
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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 inner-iterator& x, const inner-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:
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+ `return x.`*`i_`*`.`*`current`*` == y.`*`i_`*`.`*`current`*`;`
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+
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+ ``` cpp
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+ friend constexpr bool operator==(const inner-iterator& x, default_sentinel_t);
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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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+ auto [pcur, pend] = subrange{x.i_.parent_->pattern_};
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+ auto end = ranges::end(x.i_.parent_->base_);
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+ if constexpr (tiny-range<Pattern>) {
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+ const auto & cur = x.i_.current;
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+ if (cur == end) return true;
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+ if (pcur == pend) return x.incremented_;
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+ return *cur == *pcur;
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+ } else {
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+ auto cur = x.i_.current;
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+ if (cur == end) return true;
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+ if (pcur == pend) return x.incremented_;
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+ do {
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+ if (*cur != *pcur) return false;
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+ if (++pcur == pend) return true;
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+ } while (++cur != end);
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+ return false;
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+ }
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+ ```
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+
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+ ``` cpp
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+ friend constexpr void iter_swap(const inner-iterator& x, const inner-iterator& y)
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+ noexcept(noexcept(ranges::iter_swap(x.i_.current, y.i_.current)))
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+ requires indirectly_swappable<iterator_t<Base>>;
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+ ```
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+
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+ *Effects:* Equivalent to
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+ `ranges::iter_swap(x.`*`i_`*`.`*`current`*`, y.`*`i_`*`.`*`current`*`)`.
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+