basic_string_view< CharTy, CTraits > Class Template Reference

Read-only view of a string or string-like object, from C++17. See also string/basic_string_view @ cppreference . More...

Public Types
typedef CharTy	value_type
	Character type employed by the string.
typedef CTraits	traits_type
	char_traits corresponding to the character type
typedef basetype::element_type	element_type
	Element type representing the underlying buffer view.
typedef basetype::size_type	size_type
	Type representing the amount of characters the string can have.
typedef basetype::difference_type	difference_type
	Integral type representing the difference between two iterators.
typedef CharTy *	pointer
	Pointer type for the underlying character storage.
typedef CharTy const *	const_pointer
	Pointer type to a const view of the underlying character storage.
typedef CharTy &	reference
	Reference type for the underlying characters.
typedef CharTy const &	const_reference
	Reference type to a const view of the underlying characters.
typedef const_pointer	const_iterator
	Iterator type.
typedef basetype::const_reverse_iterator	const_reverse_iterator
	Reverse iterator type.

Public Member Functions
constexpr	basic_string_view () noexcept=default
	default-ctor: empty string.
constexpr	basic_string_view (basic_string_view const &) noexcept=default
	copy-ctor
CXXO_CONSTEXPR	basic_string_view (CharTy const *px, size_t sz) CXXO_NOEXCEPTNOTHROW
	string_view to characters at position px with length sz .
	basic_string_view (const_pointer const px) CXXO_NOEXCEPTNOTHROW
	string_view to characters at position px and length reported by CTraits::length .
template<typename IBegin , typename IEnd >
	basic_string_view (IBegin ini, IEnd fin)
	Iterator constructor, added in C++20.
CXXO_CONSTEXPR size_type	length () const CXXO_NOEXCEPTNOTHROW
	Returns the length of the viewed string.
const_reference	at (size_type idx) const
	Accesses characters in the string, checked.
size_type	copy (CharTy *d, size_type count, size_type pos=0) const
	Copies contents from the viewed string to a CharTy array.
basic_string_view	substr (size_type pos, size_type count=npos) const
	Returns a view of part of the string.
int	compare (basic_string_view const r) const CXXO_NOEXCEPTNOTHROW
	strcmp -like compare against another string view
CXXO_CONSTEXPR14 size_type	find (basic_string_view, size_type pos=0) const CXXO_NOEXCEPTNOTHROW
	Find a substring.
CXXO_CONSTEXPR14 size_type	find (CharTy const, size_type pos=0) const CXXO_NOEXCEPTNOTHROW
	Find a character.
size_type	find (const_pointer s, size_type pos=0) const CXXO_NOEXCEPTNOTHROW
	Find a substring.
size_type	find (const_pointer s, size_type pos, size_type count) const CXXO_NOEXCEPTNOTHROW
	Find a substring.
size_type	rfind (basic_string_view, size_type pos=0) const CXXO_NOEXCEPTNOTHROW
	Find last instance of a string.
size_type	rfind (CharTy, size_type pos=0) const CXXO_NOEXCEPTNOTHROW
	Find last instance of a character.
size_type	rfind (const_pointer s, size_type pos=0) const CXXO_NOEXCEPTNOTHROW
	Find last instance of a string.
size_type	rfind (const_pointer s, size_type pos, size_type count) const CXXO_NOEXCEPTNOTHROW
	Find last instance of a string.

Static Public Attributes
static const size_type	npos = size_type(-1)
	Flag that indicates a position not found.

Additional Inherited Members
Protected Types inherited from array_ref< T, IdxType >
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.
Protected Member Functions inherited from array_ref< T, IdxType >
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 CharTy, class CTraits = std::char_traits<CharTy>>
class cxxomfort::cxxostd::basic_string_view< CharTy, CTraits >

Read-only view of a string or string-like object, from C++17. See also string/basic_string_view @ cppreference .

A basic_string_view is a view (non-owning) to a buffer of characters representing a string object, and given a set of operations.

Differences with std::basic_string_view

Cxxomfort's basic_string_view has a number of differences from the std version in C++17 onwards, documented here for clarity. Largely the differences lie in the member functions, as cxxomfort intentionally chooses to not implement the hundreditude of member functions that std::basic_string_view inherits from the bad design of std::basic_string .

Compared to the std version, the cxxomfort implementation:

• incorporates an element_type member type equivalent to std::span 's  element_type
• incorporates a constructor from CharTy[N] for C++<11
• incorporates a constructor from std::basic_string for C++<17, to supplement the conversion operator in std::basic_string post-C++17 that can not be injected in previous versions
• incorporates an at_or() method that returns an alternative value instead of throwing an exception, when the index is out of bounds. (This is inherited from array_ref )
• does not implement remove_prefix() and remove_suffix()
• does not implement starts_with() and end_with() from C++20, leaving them instead to the global accessors in cxxomfort/string.hpp
• does not implement contains() from C++23.

Cxxomfort also offers the helper sv_helper in order to construct basic_string_view s easily; and starting with C++11 it implements the ""sv user-defined literal as well.

See also

string/basic_string_view @ cppreference .

"sv" helper sv("text")

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

• 17-string_view.hpp