[mdspan.layout.left.obs] (original) (raw)
23 Containers library [containers]
23.7 Views [views]
23.7.3 Multidimensional access [views.multidim]
23.7.3.4 Layout mapping [mdspan.layout]
23.7.3.4.5 Class template layout_left::mapping [mdspan.layout.left]
23.7.3.4.5.3 Observers [mdspan.layout.left.obs]
constexpr index_type required_span_size() const noexcept;
Returns: extents().fwd-prod-of-extents(extents_type::rank()).
template<class... Indices> constexpr index_type operator()(Indices... i) const noexcept;
Constraints:
- sizeof...(Indices) == extents_type::rank() is true,
- (is_convertible_v<Indices, index_type> && ...) is true, and
- (is_nothrow_constructible_v<index_type, Indices> && ...) is true.
Preconditions: extents_type::index-cast(i) is a multidimensional index in extents_ ([mdspan.overview]).
Effects: Let P be a parameter pack such thatis_same_v<index_sequence_for<Indices...>, index_sequence<P...>> is true.
Equivalent to:return ((static_cast<index_type>(i) * stride(P)) + ... + 0);
constexpr index_type stride(rank_type i) const;
Constraints: extents_type::rank() > 0 is true.
Preconditions: i < extents_type::rank() is true.
Returns: extents().fwd-prod-of-extents(i).
template<class OtherExtents> friend constexpr bool operator==(const mapping& x, const mapping<OtherExtents>& y) noexcept;
Constraints: extents_type::rank() == OtherExtents::rank() is true.
Effects: Equivalent to: return x.extents() == y.extents();