std::ranges::contiguous_range
From cppreference.com
| Defined in header <ranges>
|
||
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>>>; }; |
(since C++20) | |
The contiguous_range concept is a refinement of range for which ranges::begin returns a model of contiguous_iterator and the customization point ranges::data is usable.
Semantic requirements
T models contiguous_range only if given an expression e such that decltype((e)) is T&, std::to_address(ranges::begin(e)) == ranges::data(e).
Example
Run this code
#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>;
// zstring being a ranges::contiguous_range doesn't have to be a 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>>>
);
}
See also
(C++20) |
specifies that a range knows its size in constant time (concept) |
(C++20) |
specifies a range whose iterator type satisfies random_access_iterator (concept) |