From Jason Turner

[range.subrange.access]

C++17 → C++20 2.4 KB 116 lines
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Archived: C++17 | C++20
Markdown: C++17 | C++20
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  1. tmp/tmpekthf3id/{from.md → to.md} +113 -0
tmp/tmpekthf3id/{from.md → to.md} RENAMED
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+ #### Accessors <a id="range.subrange.access">[[range.subrange.access]]</a>
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+
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+ ``` cpp
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+ constexpr I begin() const requires copyable<I>;
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+ ```
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+
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+ *Effects:* Equivalent to: `return `*`begin_`*`;`
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+
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+ ``` cpp
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+ [[nodiscard]] constexpr I begin() requires (!copyable<I>);
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+ ```
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+
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+ *Effects:* Equivalent to: `return std::move(`*`begin_`*`);`
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+
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+ ``` cpp
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+ constexpr S end() const;
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+ ```
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+
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+ *Effects:* Equivalent to: `return `*`end_`*`;`
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+
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+ ``` cpp
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+ constexpr bool empty() const;
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+ ```
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+
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+ *Effects:* Equivalent to: `return `*`begin_`*` == `*`end_`*`;`
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+
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+ ``` cpp
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+ constexpr make-unsigned-like-t<iter_difference_t<I>> size() const
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+ requires (K == subrange_kind::sized);
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+ ```
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+
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+ *Effects:*
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+
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+ - If *StoreSize* is `true`, equivalent to: `return `*`size_`*`;`
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+ - Otherwise, equivalent to:
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+ `return `*`to-unsigned-like`*`(`*`end_`*` - `*`begin_`*`);`
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+
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+ ``` cpp
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+ [[nodiscard]] constexpr subrange next(iter_difference_t<I> n = 1) const &
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+ requires forward_iterator<I>;
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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 tmp = *this;
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+ tmp.advance(n);
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+ return tmp;
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+ ```
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+
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+ ``` cpp
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+ [[nodiscard]] constexpr subrange next(iter_difference_t<I> n = 1) &&;
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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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+ advance(n);
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+ return std::move(*this);
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+ ```
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+
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+ ``` cpp
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+ [[nodiscard]] constexpr subrange prev(iter_difference_t<I> n = 1) const
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+ requires bidirectional_iterator<I>;
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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 tmp = *this;
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+ tmp.advance(-n);
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+ return tmp;
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+ ```
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+
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+ ``` cpp
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+ constexpr subrange& advance(iter_difference_t<I> n);
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+ ```
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+
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+ *Effects:* Equivalent to:
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+
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+ - If *StoreSize* is `true`,
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+ ``` cpp
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+ auto d = n - ranges::advance(begin_, n, end_);
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+ if (d >= 0)
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+ size_ -= to-unsigned-like(d);
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+ else
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+ size_ += to-unsigned-like(-d);
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+ return *this;
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+ ```
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+ - Otherwise,
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+ ``` cpp
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+ ranges::advance(begin_, n, end_);
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+ return *this;
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+ ```
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+
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+ ``` cpp
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+ template<size_t N, class I, class S, subrange_kind K>
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+ requires (N < 2)
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+ constexpr auto get(const subrange<I, S, K>& r);
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+ template<size_t N, class I, class S, subrange_kind K>
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+ requires (N < 2)
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+ constexpr auto get(subrange<I, S, K>&& r);
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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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+ if constexpr (N == 0)
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+ return r.begin();
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+ else
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+ return r.end();
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+ ```
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+