array_ref< T, IdxType > Class Template Reference

An object representing a reference or slice of a contiguous area of memory of type T . More...

Public Types
typedef T	element_type
	Type of the data contained in the view.
typedef std::remove_cv< element_type >::type	value_type
	Type of variables of the type of the pointed-to data.
typedef std::add_const< value_type >::type	const_value_type
	const version of the value_type .
typedef ptrdiff_t	difference_type
	Type for the distance between pointers or iterators.
typedef IdxType	size_type
	Type for subscript / indexed access (eg.: operator[]).
typedef std::add_pointer< element_type >::type	pointer
	Type of a pointer to a contained value; potentially writable.
typedef std::add_pointer< element_type const >::type	const_pointer
	Type of a pointer to a contained value; view-only.
typedef pointer	iterator
	Iterator type; potentially writable.
typedef const_pointer	const_iterator
	Iterator type; view-only.
typedef std::reverse_iterator< iterator >	reverse_iterator
	Reverse iterator type; potentially writable.
typedef std::reverse_iterator< const_iterator >	const_reverse_iterator
	Reverse iterator type; view-only.

Public Member Functions
constexpr	array_ref () noexcept=default
	Trivial constructor; creates a view to nothing.
constexpr	array_ref (array_ref const &) noexcept=default
	Copy constructor (trivial)
constexpr array_ref &	operator= (array_ref const &) noexcept=default
	Assignment operator (trivial)
CXXO_CONSTEXPR	array_ref (pointer p, size_type len) CXXO_NOEXCEPTNOTHROW
	Construct a view to a buffer starting at p and of len units long.
CXXO_CONSTEXPR	array_ref (std::nullptr_t, pointer p, pointer q) CXXO_NOEXCEPTNOTHROW
	Construct a view to a buffer starting at p and ending at q (not in the original n3334 proposal).
template<size_t N>
CXXO_CONSTEXPR	array_ref (T(&arr)[N]) CXXO_NOEXCEPTNOTHROW
	Constructs a view over a native C array.
reference	operator[] (size_type i) CXXO_NOEXCEPTNOTHROW
	Unchecked access to the i -th element.
CXXO_CONSTEXPR const_reference	operator[] (size_type i) const CXXO_NOEXCEPTNOTHROW
	Unchecked access to the i -th element.
reference	at (size_type i)
	Checked access to the i -th element; throw.
const_reference	at (size_type i) const
	Checked access to the i -th element; throw.
reference	at_or (size_type i, reference alt) CXXO_NOEXCEPTNOTHROW
	Checked access to the i -th element; returns an alternative if it doesn't exist.
CXXO_CONSTEXPR const_reference	at_or (size_type i, const_reference alt) const CXXO_NOEXCEPTNOTHROW
	Checked access to the i -th element; returns an alternative if it doesn't exist.
CXXO_CONSTEXPR size_type	size () const CXXO_NOEXCEPTNOTHROW
CXXO_CONSTEXPR bool	empty () const CXXO_NOEXCEPTNOTHROW
CXXO_CONSTEXPR14 pointer	data () CXXO_NOEXCEPTNOTHROW
CXXO_CONSTEXPR const_pointer	data () const CXXO_NOEXCEPTNOTHROW
CXXO_CONSTEXPR size_type	size_bytes () const CXXO_NOEXCEPTNOTHROW
CXXO_CONSTEXPR const_iterator	cbegin () const CXXO_NOEXCEPTNOTHROW
	begin
CXXO_CONSTEXPR const_iterator	cend () const CXXO_NOEXCEPTNOTHROW
	end
iterator	begin () CXXO_NOEXCEPTNOTHROW
	begin
iterator	end () CXXO_NOEXCEPTNOTHROW
	end
CXXO_CONSTEXPR const_iterator	begin () const CXXO_NOEXCEPTNOTHROW
	begin
CXXO_CONSTEXPR const_iterator	end () const CXXO_NOEXCEPTNOTHROW
	end
CXXO_CONSTEXPR const_reverse_iterator	crbegin () const CXXO_NOEXCEPTNOTHROW
	reverse-begin
CXXO_CONSTEXPR const_reverse_iterator	crend () const CXXO_NOEXCEPTNOTHROW
	reverse-end
reverse_iterator	rbegin () CXXO_NOEXCEPTNOTHROW
	reverse-begin
reverse_iterator	rend () CXXO_NOEXCEPTNOTHROW
	reverse-end
const_reverse_iterator	rbegin () const CXXO_NOEXCEPTNOTHROW
	reverse-begin
const_reverse_iterator	rend () const CXXO_NOEXCEPTNOTHROW
	reverse-end
const_iterator	front () const CXXO_NOEXCEPTNOTHROW
	Unchecked (!) access to the 0th element.
iterator	front () CXXO_NOEXCEPTNOTHROW
	Unchecked (!) access to the 0th element.
const_iterator	back () const CXXO_NOEXCEPTNOTHROW
	Unchecked (!) access to the last element.
iterator	back () CXXO_NOEXCEPTNOTHROW
	Unchecked (!) access to the last element.
CXXO_CONSTEXPR array_ref	substr (size_type pos, size_type count) const
	Returns a view to the count -elements subsequence starting from pos .
array_ref	substr (size_type pos) const
array_ref	leftmost (size_type n) const CXXO_NOEXCEPTNOTHROW
	Returns a view to the leftmost (first) n elements.
array_ref	rightmost (size_type n) const CXXO_NOEXCEPTNOTHROW
	Returns a view to the rightmost (last) n elements.
array_ref	slice (difference_type pos, size_type count) const
	Returns a view of sub-contents from position pos which can be negative, ala PHP, JS.
array_ref	slice (difference_type pos) const
array_ref	without_back_n (size_type n) const
	Removes the last n elements.
array_ref	without_front_n (size_type n) const
	Removes the first n elements.
array_ref	without_back () const
	Returns a view with the last element removed.
array_ref	without_front () const
	Returns a view with the first element removed.

Detailed Description

template<class T, class IdxType = size_t>
class cxxomfort::impl::array_ref::array_ref< T, IdxType >

An object representing a reference or slice of a contiguous area of memory of type T .

Template Parameters

T	Type of the kind of value contained in the view.
IdxType	A numeric type to be used as the index, defaults to size_t .

Supplements:

A array_ref is a non-owning view of a sequence of contiguous elements via a simple {pointer+length} package. In many ways it could be considered an analogue to std::array except it doesn't actually hold the data (hence the name, array_ref ), and to std::reference_wrapper.

Being a reference/view type, it is good to pass by value. Also, iterator types are raw pointers.

This implementation is intended to be used for sequences of const elements (ie.: template argument is T const).

The utility function arrayref() and carrayref() help create array_refs from contexts where they can be needed.

See also: std::array, std::vector, seq_ .

Differences with std::basic_string_view

• Allows for a array_ref of non-const objects.
• Allows for an index type shorter than size_t (for eg.: short alloc buffers).
• Adds ( pointer , pointer ) constructor.
• Discards vector constructor for lower dependency overhead.
• Adds member functions front , back .
• Adds member functions leftmost , rightmost .
• Ally functions arrayref() and carrayref() provided as support.

See Also

array_ref is based in the original publication "n3334" by Jeffrey Yasskin

See also

WG21 index n3334 array_ref container/span @ cppreference

Member Function Documentation

size()

CXXO_CONSTEXPR size_type size ( ) const

inline

Returns

size of the view as a size_t .

Referenced by array_ref< Ch const >::at_or(), array_ref< Ch const >::back(), basic_string_view< Ch, ChT >::copy(), array_ref< Ch const >::empty(), cxxomfort::string::find(), basic_string_view< Ch, ChT >::find(), basic_string_view< Ch, ChT >::length(), and basic_string_view< Ch, ChT >::substr().

empty()

CXXO_CONSTEXPR bool empty ( ) const

inline

Returns

bool .

Referenced by array_ref< Ch const >::rightmost().

data() [1/2]

CXXO_CONSTEXPR14 pointer data ( )

inline

Returns

pointer to the view's data.

Referenced by array_ref< Ch const >::back(), basic_string_view< Ch, ChT >::copy(), cxxomfort::string::find(), and basic_string_view< Ch, ChT >::substr().

data() [2/2]

CXXO_CONSTEXPR const_pointer data ( ) const

inline

Returns

pointer to the view's data.

size_bytes()

CXXO_CONSTEXPR size_type size_bytes ( ) const

inline

Returns

size of the view in bytes.

substr()

array_ref substr

(

size_type

pos

)

const

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

slice()

array_ref slice

(

difference_type

pos

)

const

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

---

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

• n3334-array_ref.hpp