std::ranges::contiguous_range

 

C++

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自立实现与有宿主实现

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功能特性测试宏 (C++20)

语言支持库

概念库 (C++20)

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元编程库 (C++11)

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范围库 (C++20)

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技术规范

符号索引

外部库

 

范围库

范围访问 begin cbegin   end cend rbegin crbegin   rend crend size ssize   data cdata reserve_hint (C++26)   empty

范围转换 std::from_range_t std::from_range (C++23)(C++23)     to (C++23)

悬垂迭代器处理 dangling borrowed_iterator_t borrowed_subrange_t

范围原语
range_size_trange_difference_trange_value_t elements_of (C++23)	iterator_tconst_iterator_tsentinel_tconst_sentinel_t (C++23)(C++23)	range_reference_trange_const_reference_trange_rvalue_reference_trange_common_reference_t (C++23)

范围概念
range borrowed_range    common_range	sized_range viewable_range    view	input_range output_range forward_range	bidirectional_range    random_access_range contiguous_range	approximately_sized_range (C++26) constant_range (C++23)

视图
view_interface	subrange

范围工厂
empty_viewviews::empty	single_viewviews::single	basic_istream_viewviews::istream	iota_viewviews::iota	repeat_viewviews::repeat (C++23)(C++23)

范围适配器
views::all_tviews::all as_rvalue_viewviews::as_rvalue (C++23)(C++23)   filter_viewviews::filter transform_viewviews::transform take_viewviews::take take_while_viewviews::take_while common_viewviews::common views::counted to_input_viewviews::to_input (C++26)(C++26)	ref_view drop_viewviews::drop drop_while_viewviews::drop_while lazy_split_viewviews::lazy_split split_viewviews::split join_viewviews::join join_with_viewviews::join_with (C++23)(C++23)   concat_viewviews::concat (C++26)(C++26) cache_latest_viewviews::cache_latest (C++26)(C++26)	owning_view reverse_viewviews::reverse as_const_viewviews::as_const (C++23)(C++23) elements_viewviews::elements keys_viewviews::keys values_viewviews::values enumerate_viewviews::enumerate (C++23)(C++23) zip_viewviews::zip (C++23)(C++23) zip_transform_viewviews::zip_transform (C++23)(C++23)	adjacent_viewviews::adjacent (C++23)(C++23) views::pairwise (C++23) adjacent_transform_viewviews::adjacent_transform (C++23)(C++23) views::pairwise_transform (C++23) chunk_viewviews::chunk (C++23)(C++23) slide_viewviews::slide (C++23)(C++23) chunk_by_viewviews::chunk_by (C++23)(C++23) stride_viewviews::stride (C++23)(C++23) cartesian_product_viewviews::cartesian_product (C++23)(C++23)

范围生成器 std::generator (C++23)

范围适配器闭包对象 range_adaptor_closure (C++23)

范围适配器对象

辅助项
copyable-box movable-box (C++23 前)  (C++23)	simple-view non-propagating-cache

 

在标头 <ranges> 定义
template< class T > concept contiguous_range =     ranges::random_access_range<T> &&     std::contiguous_iterator<ranges::iterator_t<T>> &&     requires(T& t) {         { ranges::data(t) } ->             std::same_as<std::add_pointer_t<ranges::range_reference_t<T>>>;     };		(C++20 起)

contiguous_range 概念是 range 的精化，对于实现它的类型，ranges::begin 返回 contiguous_iterator 的实现，且定制点 ranges::data 可用。

语义要求

仅若给定表达式 e 使得 decltype((e)) 为 T&，std::to_address(ranges::begin(t)) == ranges::data(t) 时，T 实现 contiguous_range。

示例

运行此代码

#include <array>
#include <deque>
#include <list>
#include <mdspan>
#include <ranges>
#include <set>
#include <span>
#include <string_view>
#include <valarray>
#include <vector>
 
template<typename T>
concept CR = std::ranges::contiguous_range<T>;
 
// 作为 ranges::contiguous_range 的 zstring 不必是 ranges::sized_range
struct zstring
{
    struct sentinel
    {
        friend constexpr bool operator==(const char* str, sentinel) noexcept
        { return *str == '\0'; }
    };
 
    const char* str;
 
    const char* begin() const noexcept { return str; }
    sentinel end() const noexcept { return {}; }
};
 
int main()
{
    int a[4];
    static_assert(
            CR<std::vector<int>> and
        not CR<std::vector<bool>> and
        not CR<std::deque<int>> and
            CR<std::valarray<int>> and
            CR<decltype(a)> and
        not CR<std::list<int>> and
        not CR<std::set<int>> and
            CR<std::array<std::list<int>,42>> and
            CR<std::string_view> and
            CR<zstring> and
            CR<std::span<const int>> and
        not CR<std::mdspan<int, std::dims<1>>>
    );
}

参阅

ranges::sized_range (C++20)	指定范围可以常数时间计算大小 (概念)
ranges::random_access_range (C++20)	指定范围的迭代器类型满足 random_access_iterator (概念)