All member functions of
span have constant time complexity
.
namespace std {
template<class ElementType, ptrdiff_t Extent = dynamic_extent>
class span {
public:
using element_type = ElementType;
using value_type = remove_cv_t<ElementType>;
using index_type = ptrdiff_t;
using difference_type = ptrdiff_t;
using pointer = element_type*;
using reference = element_type&;
using iterator = implementation-defined;
using const_iterator = implementation-defined;
using reverse_iterator = std::reverse_iterator<iterator>;
using const_reverse_iterator = std::reverse_iterator<const_iterator>;
static constexpr index_type extent = Extent;
constexpr span() noexcept;
constexpr span(pointer ptr, index_type count);
constexpr span(pointer first, pointer last);
template<size_t N>
constexpr span(element_type (&arr)[N]) noexcept;
template<size_t N>
constexpr span(array<value_type, N>& arr) noexcept;
template<size_t N>
constexpr span(const array<value_type, N>& arr) noexcept;
template<class Container>
constexpr span(Container& cont);
template<class Container>
constexpr span(const Container& cont);
constexpr span(const span& other) noexcept = default;
template<class OtherElementType, ptrdiff_t OtherExtent>
constexpr span(const span<OtherElementType, OtherExtent>& s) noexcept;
~span() noexcept = default;
constexpr span& operator=(const span& other) noexcept = default;
template<ptrdiff_t Count>
constexpr span<element_type, Count> first() const;
template<ptrdiff_t Count>
constexpr span<element_type, Count> last() const;
template<ptrdiff_t Offset, ptrdiff_t Count = dynamic_extent>
constexpr span<element_type, see below> subspan() const;
constexpr span<element_type, dynamic_extent> first(index_type count) const;
constexpr span<element_type, dynamic_extent> last(index_type count) const;
constexpr span<element_type, dynamic_extent> subspan(
index_type offset, index_type count = dynamic_extent) const;
constexpr index_type size() const noexcept;
constexpr index_type size_bytes() const noexcept;
constexpr bool empty() const noexcept;
constexpr reference operator[](index_type idx) const;
constexpr reference operator()(index_type idx) const;
constexpr pointer data() const noexcept;
constexpr iterator begin() const noexcept;
constexpr iterator end() const noexcept;
constexpr const_iterator cbegin() const noexcept;
constexpr const_iterator cend() const noexcept;
constexpr reverse_iterator rbegin() const noexcept;
constexpr reverse_iterator rend() const noexcept;
constexpr const_reverse_iterator crbegin() const noexcept;
constexpr const_reverse_iterator crend() const noexcept;
private:
pointer data_; index_type size_; };
template<class T, size_t N>
span(T (&)[N]) -> span<T, N>;
template<class T, size_t N>
span(array<T, N>&) -> span<T, N>;
template<class T, size_t N>
span(const array<T, N>&) -> span<const T, N>;
template<class Container>
span(Container&) -> span<typename Container::value_type>;
template<class Container>
span(const Container&) -> span<const typename Container::value_type>;
}