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std::extents

From cppreference.com
< cpp‎ | container‎ | mdspan
 
 
 
 
Defined in header <mdspan>
template<class IndexType, std::size_t... Extents>
class extents;
(since C++23)

The class template extents represents a multidimensional index space of rank equal to sizeof...(Extents).

Each specialization of extents models regular and is TriviallyCopyable.

Contents

[edit] Template parameters

IndexType - the type of each non-dynamic Extents. Shall be a signed or unsigned integer type. Otherwise, the program is ill-formed.
Extents - represents extent (size of an integer interval) for each rank index. Each element of it is either equal to std::dynamic_extent (in this case, it represents a dynamic extent and the extent size shall be determined dynamically), or is representable as a value of type IndexType (then it represents a static extent and the extent size is just the value of it), or else the program is ill-formed.

[edit] Member types

Member type Definition
index_type IndexType
size_type std::make_unsigned_t<index_type>
rank_type std::size_t

[edit] Data members

Typical implementations only hold one non-static data member:

  • dynamic-extents in type std::array<index_type, rank_dynamic()>, stores the size of each dynamic extents. The name is for exposition only.

[edit] Member functions

constructs an extents
(public member function) [edit]
Observers
[static]
returns the static rank of an extents
(public static member function) [edit]
returns the dynamic rank of an extents
(public static member function) [edit]
returns static extent size of an extents at a certain rank index
(public static member function) [edit]
returns dynamic extent size of an extents at a certain rank index
(public member function) [edit]
Public exposition-only helpers
returns the product of extent size in range [0i). The name is for exposition only.
(public member function) [edit]
returns the product of extents size in range [i + 1rank()). The name is for exposition only.
(public member function) [edit]
casts the input into an integer type. The name is for exposition only.
(public member function) [edit]
Private exposition-only helpers
returns the number of dynamic extents below a certain rank index. The name is for exposition only.
(private member function) [edit]
returns the number r that in range [0r + 1) there is exactly i + 1 dynamic extents for a certain argument i. The name is for exposition only.
(private member function) [edit]

[edit] Non-member functions

compare underlying extents in each dimension of two extents
(function) [edit]

[edit] Deduction guides

[edit] Example