span< T, Extent > Struct Template Reference

A non-owning view over a contiguous sequence of objects. More...

#include <span.hpp>

Public Types
using	const_pointer = T const*
using	const_reference = T const&
using	difference_type = etl::ptrdiff_t
using	element_type = T
using	iterator = T*
using	pointer = T*
using	reference = T&
using	reverse_iterator = etl::reverse_iterator<iterator>
using	size_type = etl::size_t
using	value_type = etl::remove_cv_t<T>

Public Member Functions
constexpr	span () noexcept=default
	Constructs a span. Constructs an empty span whose data() == nullptr and size() == 0.
constexpr auto	back () const -> reference
	Returns a reference to the last element in the span. Calling front on an empty span results in undefined behavior.
constexpr auto	begin () const noexcept -> iterator
	Returns an iterator to the first element of the span. If the span is empty, the returned iterator will be equal to end().
constexpr auto	data () const noexcept -> pointer
	Returns a pointer to the beginning of the sequence.
constexpr auto	empty () const noexcept -> bool
	Checks if the span is empty.
constexpr auto	end () const noexcept -> iterator
	Returns an iterator to the element following the last element of the span. This element acts as a placeholder; attempting to access it results in undefined behavior.
template<typename It> requires detail::span_convertible_from<remove_reference_t<iter_reference_t<It>>, T>
	explicit (extent !=dynamic_extent) const expr span(It first
	Constructs a span.
template<size_t Count>
constexpr auto	first () const -> span< element_type, Count >
	Obtains a span that is a view over the first Count elements of this span. The program is ill-formed if Count > Extent.
constexpr auto	first (size_type count) const -> span< element_type, dynamic_extent >
	Obtains a span that is a view over the first Count elements of this span. The behavior is undefined if Count > size().
constexpr auto	front () const -> reference
	Returns a reference to the first element in the span. Calling front on an empty span results in undefined behavior.
template<size_t Count>
constexpr auto	last () const -> span< element_type, Count >
	Obtains a span that is a view over the last Count elements of this span. The program is ill-formed if Count > Extent.
constexpr auto	last (size_type count) const -> span< element_type, dynamic_extent >
	Obtains a span that is a view over the last Count elements of this span. The behavior is undefined if Count > size().
constexpr auto	operator[] (size_type idx) const -> reference
	Returns a reference to the idx-th element of the sequence. The behavior is undefined if idx is out of range (i.e., if it is greater than or equal to size()).
constexpr auto	rbegin () const noexcept -> reverse_iterator
	Returns a reverse iterator to the first element of the reversed span. It corresponds to the last element of the non-reversed span. If the span is empty, the returned iterator is equal to rend().
constexpr auto	rend () const noexcept -> reverse_iterator
	Returns a reverse iterator to the element following the last element of the reversed span. It corresponds to the element preceding the first element of the non-reversed span. This element acts as a placeholder, attempting to access it results in undefined behavior.
constexpr auto	size () const noexcept -> size_type
	Returns the number of elements in the span.
constexpr auto	size_bytes () const noexcept -> size_type
	Returns the number of elements in the span.
template<size_t Offset, size_t Count = dynamic_extent>
constexpr auto	subspan () const -> span< T, detail::subspan_extent< Offset, Count, Extent >()>
	Obtains a span that is a view over the Count elements of this span starting at offset Offset. If Count is etl::dynamic_extent, the number of elements in the subspan is size() - offset (i.e., it ends at the end of *this.).
constexpr auto	subspan (size_type offset, size_type count=dynamic_extent) const -> span< T, dynamic_extent >
	Obtains a span that is a view over the Count elements of this span starting at offset Offset. If Count is etl::dynamic_extent, the number of elements in the subspan is size() - offset (i.e., it ends at the end of *this.).

Public Attributes
size_type	count: _storage{first

Static Public Attributes
static constexpr size_type	extent = Extent
	The number of elements in the sequence, or etl::dynamic_extent if dynamic.

Related Symbols
(Note that these are not member symbols.)
template<typename T, size_t N>
auto	as_bytes (span< T, N > s) noexcept -> span< byte const, detail::span_as_bytes_size< T, N > >
	Obtains a view to the object representation of the elements of the span s.
template<typename T, size_t N>
auto	as_writable_bytes (span< T, N > s) noexcept -> span< byte, detail::span_as_bytes_size< T, N > >
	Obtains a view to the object representation of the elements of the span s.

Detailed Description

template<typename T, size_t Extent>
struct etl::span< T, Extent >

A non-owning view over a contiguous sequence of objects.

The class template span describes an object that can refer to a contiguous sequence of objects with the first element of the sequence at position zero. A span can either have a static extent, in which case the number of elements in the sequence is known and encoded in the type, or a dynamic extent.

If a span has dynamic extent a typical implementation holds two members: a pointer to T and a size. A span with static extent may have only one member: a pointer to T.

Examples

numeric.cpp.

Member Typedef Documentation

const_pointer

template<typename T, size_t Extent>

using const_pointer = T const*

const_reference

template<typename T, size_t Extent>

using const_reference = T const&

difference_type

template<typename T, size_t Extent>

using difference_type = etl::ptrdiff_t

element_type

template<typename T, size_t Extent>

using element_type = T

iterator

template<typename T, size_t Extent>

using iterator = T*

pointer

template<typename T, size_t Extent>

using pointer = T*

reference

template<typename T, size_t Extent>

using reference = T&

reverse_iterator

template<typename T, size_t Extent>

using reverse_iterator = etl::reverse_iterator<iterator>

size_type

template<typename T, size_t Extent>

using size_type = etl::size_t

value_type

template<typename T, size_t Extent>

using value_type = etl::remove_cv_t<T>

Constructor & Destructor Documentation

span()

template<typename T, size_t Extent>

span ( )

constexprdefaultnoexcept

Constructs a span. Constructs an empty span whose data() == nullptr and size() == 0.

This overload only participates in overload resolution if extent == 0 || extent == etl::dynamic_extent.

Member Function Documentation

back()

template<typename T, size_t Extent>

auto back ( ) const -> reference

inlinenodiscardconstexpr

Returns a reference to the last element in the span. Calling front on an empty span results in undefined behavior.

begin()

template<typename T, size_t Extent>

auto begin ( ) const -> iterator

inlinenodiscardconstexprnoexcept

Returns an iterator to the first element of the span. If the span is empty, the returned iterator will be equal to end().

data()

template<typename T, size_t Extent>

auto data ( ) const -> pointer

inlinenodiscardconstexprnoexcept

Returns a pointer to the beginning of the sequence.

empty()

template<typename T, size_t Extent>

auto empty ( ) const -> bool

inlinenodiscardconstexprnoexcept

Checks if the span is empty.

end()

template<typename T, size_t Extent>

auto end ( ) const -> iterator

inlinenodiscardconstexprnoexcept

Returns an iterator to the element following the last element of the span. This element acts as a placeholder; attempting to access it results in undefined behavior.

explicit()

template<typename T, size_t Extent>

template<typename It>
requires detail::span_convertible_from<remove_reference_t<iter_reference_t<It>>, T>

explicit

(

extent !

= dynamic_extent

)

const

Constructs a span.

Constructs a span that is a view over the range [first, first + count);

first() [1/2]

template<typename T, size_t Extent>

template<size_t Count>

auto first ( ) const -> span<element_type, Count>

inlinenodiscardconstexpr

Obtains a span that is a view over the first Count elements of this span. The program is ill-formed if Count > Extent.

first() [2/2]

template<typename T, size_t Extent>

auto first ( size_type count ) const -> span<element_type, dynamic_extent>

inlinenodiscardconstexpr

Obtains a span that is a view over the first Count elements of this span. The behavior is undefined if Count > size().

front()

template<typename T, size_t Extent>

auto front ( ) const -> reference

inlinenodiscardconstexpr

Returns a reference to the first element in the span. Calling front on an empty span results in undefined behavior.

last() [1/2]

template<typename T, size_t Extent>

template<size_t Count>

auto last ( ) const -> span<element_type, Count>

inlinenodiscardconstexpr

Obtains a span that is a view over the last Count elements of this span. The program is ill-formed if Count > Extent.

last() [2/2]

template<typename T, size_t Extent>

auto last ( size_type count ) const -> span<element_type, dynamic_extent>

inlinenodiscardconstexpr

Obtains a span that is a view over the last Count elements of this span. The behavior is undefined if Count > size().

operator[]()

template<typename T, size_t Extent>

auto operator[] ( size_type idx ) const -> reference

inlinenodiscardconstexpr

Returns a reference to the idx-th element of the sequence. The behavior is undefined if idx is out of range (i.e., if it is greater than or equal to size()).

rbegin()

template<typename T, size_t Extent>

auto rbegin ( ) const -> reverse_iterator

inlinenodiscardconstexprnoexcept

Returns a reverse iterator to the first element of the reversed span. It corresponds to the last element of the non-reversed span. If the span is empty, the returned iterator is equal to rend().

rend()

template<typename T, size_t Extent>

auto rend ( ) const -> reverse_iterator

inlinenodiscardconstexprnoexcept

Returns a reverse iterator to the element following the last element of the reversed span. It corresponds to the element preceding the first element of the non-reversed span. This element acts as a placeholder, attempting to access it results in undefined behavior.

size()

template<typename T, size_t Extent>

auto size ( ) const -> size_type

inlinenodiscardconstexprnoexcept

Returns the number of elements in the span.

size_bytes()

template<typename T, size_t Extent>

auto size_bytes ( ) const -> size_type

inlinenodiscardconstexprnoexcept

Returns the number of elements in the span.

subspan() [1/2]

template<typename T, size_t Extent>

template<size_t Offset, size_t Count = dynamic_extent>

auto subspan ( ) const -> span<T, detail::subspan_extent<Offset, Count, Extent>()>

inlinenodiscardconstexpr

Obtains a span that is a view over the Count elements of this span starting at offset Offset. If Count is etl::dynamic_extent, the number of elements in the subspan is size() - offset (i.e., it ends at the end of *this.).

subspan() [2/2]

template<typename T, size_t Extent>

auto subspan ( size_type offset, size_type count = dynamic_extent ) const -> span<T, dynamic_extent>

inlinenodiscardconstexpr

Obtains a span that is a view over the Count elements of this span starting at offset Offset. If Count is etl::dynamic_extent, the number of elements in the subspan is size() - offset (i.e., it ends at the end of *this.).

Member Data Documentation

count

template<typename T, size_t Extent>

size_type count

extent

template<typename T, size_t Extent>

size_type extent = Extent

staticconstexpr

The number of elements in the sequence, or etl::dynamic_extent if dynamic.

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The documentation for this struct was generated from the following file:

• include/etl/_span/span.hpp