[/
Copyright 2021 Peter Dimov
Distributed under the Boost Software License, Version 1.0.
https://boost.org/LICENSE_1_0.txt
]
[section:string_view string_view]
[simplesect Authors]
* Peter Dimov
[endsimplesect]
[section Header <boost/core/string_view.hpp>]
The header `<boost/core/string_view.hpp>` defines `boost::core::string_view`,
a portable and interoperable implementation of `std::string_view`.
Unlike `boost::string_view`, `boost::core::string_view` has implicit
conversions from and to `std::string_view`, which allows Boost libraries that
support C++11/C++14 to use it in interfaces without forcing users to forgo the
use of `std::string_view` in their code.
[section Synopsis]
``
namespace boost
{
namespace core
{
template<class Ch> class basic_string_view
{
public:
// types
typedef std::char_traits<Ch> traits_type;
typedef Ch value_type;
typedef Ch* pointer;
typedef Ch const* const_pointer;
typedef Ch& reference;
typedef Ch const& const_reference;
typedef Ch const* const_iterator;
typedef const_iterator iterator;
typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
typedef const_reverse_iterator reverse_iterator;
typedef std::size_t size_type;
typedef std::ptrdiff_t difference_type;
// npos
static constexpr size_type npos = static_cast<size_type>( -1 );
public:
// construction and assignment
constexpr basic_string_view() noexcept;
constexpr basic_string_view( basic_string_view const& ) noexcept = default;
constexpr basic_string_view& operator=( basic_string_view const& ) noexcept & = default;
constexpr basic_string_view( Ch const* str ) noexcept;
constexpr basic_string_view( Ch const* str, size_type len ) noexcept;
constexpr basic_string_view( Ch const* begin, Ch const* end ) noexcept;
template<class A> basic_string_view( std::basic_string<Ch, std::char_traits<Ch>, A> const& str ) noexcept;
basic_string_view( std::basic_string_view<Ch, std::char_traits<Ch>> const& str ) noexcept;
// conversions
template<class A> operator std::basic_string<Ch, std::char_traits<Ch>, A>() const;
template<class Ch2> operator std::basic_string_view<Ch2>() const noexcept;
// iterator support
constexpr const_iterator begin() const noexcept;
constexpr const_iterator end() const noexcept;
constexpr const_iterator cbegin() const noexcept;
constexpr const_iterator cend() const noexcept;
constexpr const_reverse_iterator rbegin() const noexcept;
constexpr const_reverse_iterator rend() const noexcept;
constexpr const_reverse_iterator crbegin() const noexcept;
constexpr const_reverse_iterator crend() const noexcept;
// capacity
constexpr size_type size() const noexcept;
constexpr size_type length() const noexcept;
constexpr size_type max_size() const noexcept;
constexpr bool empty() const noexcept;
// element access
constexpr const_reference operator[]( size_type pos ) const noexcept;
constexpr const_reference at( size_type pos ) const;
constexpr const_reference front() const noexcept;
constexpr const_reference back() const noexcept;
constexpr const_pointer data() const noexcept;
// modifiers
constexpr void remove_prefix( size_type n ) noexcept;
constexpr void remove_suffix( size_type n ) noexcept;
constexpr void swap( basic_string_view& s ) noexcept;
// string operations
constexpr size_type copy( Ch* s, size_type n, size_type pos = 0 ) const;
constexpr basic_string_view substr( size_type pos = 0, size_type n = npos ) const;
// compare
constexpr int compare( basic_string_view str ) const noexcept;
constexpr int compare( size_type pos1, size_type n1, basic_string_view str ) const;
constexpr int compare( size_type pos1, size_type n1, basic_string_view str, size_type pos2, size_type n2 ) const;
constexpr int compare( Ch const* s ) const;
constexpr int compare( size_type pos1, size_type n1, Ch const* s ) const;
constexpr int compare( size_type pos1, size_type n1, Ch const* s, size_type n2 ) const;
// starts_with
constexpr bool starts_with( basic_string_view x ) const noexcept;
constexpr bool starts_with( Ch x ) const noexcept;
constexpr bool starts_with( Ch const* x ) const noexcept;
// ends_with
constexpr bool ends_with( basic_string_view x ) const noexcept;
constexpr bool ends_with( Ch x ) const noexcept;
constexpr bool ends_with( Ch const* x ) const noexcept;
// find
constexpr size_type find( basic_string_view str, size_type pos = 0 ) const noexcept;
constexpr size_type find( Ch c, size_type pos = 0 ) const noexcept;
constexpr size_type find( Ch const* s, size_type pos, size_type n ) const noexcept;
constexpr size_type find( Ch const* s, size_type pos = 0 ) const noexcept;
// rfind
constexpr size_type rfind( basic_string_view str, size_type pos = npos ) const noexcept;
constexpr size_type rfind( Ch c, size_type pos = npos ) const noexcept;
constexpr size_type rfind( Ch const* s, size_type pos, size_type n ) const noexcept;
constexpr size_type rfind( Ch const* s, size_type pos = npos ) const noexcept;
// find_first_of
constexpr size_type find_first_of( basic_string_view str, size_type pos = 0 ) const noexcept;
constexpr size_type find_first_of( Ch c, size_type pos = 0 ) const noexcept;
constexpr size_type find_first_of( Ch const* s, size_type pos, size_type n ) const noexcept;
constexpr size_type find_first_of( Ch const* s, size_type pos = 0 ) const noexcept;
// find_last_of
constexpr size_type find_last_of( basic_string_view str, size_type pos = npos ) const noexcept;
constexpr size_type find_last_of( Ch c, size_type pos = npos ) const noexcept;
constexpr size_type find_last_of( Ch const* s, size_type pos, size_type n ) const noexcept;
constexpr size_type find_last_of( Ch const* s, size_type pos = npos ) const noexcept;
// find_first_not_of
constexpr size_type find_first_not_of( basic_string_view str, size_type pos = 0 ) const noexcept;
constexpr size_type find_first_not_of( Ch c, size_type pos = 0 ) const noexcept;
constexpr size_type find_first_not_of( Ch const* s, size_type pos, size_type n ) const noexcept;
constexpr size_type find_first_not_of( Ch const* s, size_type pos = 0 ) const noexcept;
// find_last_not_of
constexpr size_type find_last_not_of( basic_string_view str, size_type pos = npos ) const noexcept;
constexpr size_type find_last_not_of( Ch c, size_type pos = npos ) const noexcept;
constexpr size_type find_last_not_of( Ch const* s, size_type pos, size_type n ) const noexcept;
constexpr size_type find_last_not_of( Ch const* s, size_type pos = npos ) const noexcept;
// contains
constexpr bool contains( basic_string_view sv ) const noexcept;
constexpr bool contains( Ch c ) const noexcept;
constexpr bool contains( Ch const* s ) const noexcept;
// relational operators
constexpr friend bool operator==( basic_string_view sv1, basic_string_view sv2 ) noexcept;
constexpr friend bool operator!=( basic_string_view sv1, basic_string_view sv2 ) noexcept;
constexpr friend bool operator<( basic_string_view sv1, basic_string_view sv2 ) noexcept;
constexpr friend bool operator<=( basic_string_view sv1, basic_string_view sv2 ) noexcept;
constexpr friend bool operator>( basic_string_view sv1, basic_string_view sv2 ) noexcept;
constexpr friend bool operator>=( basic_string_view sv1, basic_string_view sv2 ) noexcept;
};
// stream inserter
template<class Ch> std::basic_ostream<Ch>& operator<<( std::basic_ostream<Ch>& os, basic_string_view<Ch> str );
// typedef names
typedef basic_string_view<char> string_view;
typedef basic_string_view<wchar_t> wstring_view;
typedef basic_string_view<char16_t> u16string_view;
typedef basic_string_view<char32_t> u32string_view;
typedef basic_string_view<char8_t> u8string_view;
} // namespace core
} // namespace boost
``
[endsect]
[section Construction]
[section `constexpr basic_string_view() noexcept;`]
* *Ensures:* `data() == 0`; `size() == 0`.
[endsect]
[section `constexpr basic_string_view( Ch const* str ) noexcept;`]
* *Ensures:* `data() == str`; `size() == traits_type::length( str )`.
[endsect]
[section `constexpr basic_string_view( Ch const* str, size_type len ) noexcept;`]
* *Ensures:* `data() == str`; `size() == len`.
[endsect]
[section `constexpr basic_string_view( Ch const* begin, Ch const* end ) noexcept;`]
* *Requires:* `end >= begin`.
* *Ensures:* `data() == begin`; `size() == end - begin`.
[endsect]
[section `template<class A> basic_string_view( std::basic_string<Ch, std::char_traits<Ch>, A> const& str ) noexcept;`]
* *Ensures:* `data() == str.data()`; `size() == str.size()`.
[endsect]
[section `basic_string_view( std::basic_string_view<Ch, std::char_traits<Ch>> const& str ) noexcept;`]
* *Ensures:* `data() == str.data()`; `size() == str.size()`.
[endsect]
[endsect]
[section Conversions]
[section `template<class A> operator std::basic_string<Ch, std::char_traits<Ch>, A>() const;`]
* *Returns:* `std::basic_string<Ch, std::char_traits<Ch>, A>( data(), size() )`.
[endsect]
[section `template<class Ch2> operator std::basic_string_view<Ch2>() const noexcept;`]
* *Constraints:* `Ch2` is the same type as `Ch`.
* *Returns:* `std::basic_string_view<Ch2>( data(), size() )`.
[endsect]
[endsect]
[section Iterator Support]
[section `constexpr const_iterator begin() const noexcept;`]
* *Returns:* `data()`.
[endsect]
[section `constexpr const_iterator end() const noexcept;`]
* *Returns:* `data() + size()`.
[endsect]
[section `constexpr const_iterator cbegin() const noexcept;`]
* *Returns:* `begin()`.
[endsect]
[section `constexpr const_iterator cend() const noexcept;`]
* *Returns:* `end()`.
[endsect]
[section `constexpr const_reverse_iterator rbegin() const noexcept;`]
* *Returns:* `const_reverse_iterator( end() )`.
[endsect]
[section `constexpr const_reverse_iterator rend() const noexcept;`]
* *Returns:* `const_reverse_iterator( begin() )`.
[endsect]
[section `constexpr const_reverse_iterator crbegin() const noexcept;`]
* *Returns:* `rbegin()`.
[endsect]
[section `constexpr const_reverse_iterator crend() const noexcept;`]
* *Returns:* `rend()`.
[endsect]
[endsect]
[section Capacity]
[section `constexpr size_type size() const noexcept;`]
* *Returns:* the length of the referenced character sequence.
[endsect]
[section `constexpr size_type length() const noexcept;`]
* *Returns:* `size()`.
[endsect]
[section `constexpr size_type max_size() const noexcept;`]
* *Returns:* `std::numeric_limits<size_type>::max() / sizeof(Ch)`.
[endsect]
[section `constexpr bool empty() const noexcept;`]
* *Returns:* `size() == 0`.
[endsect]
[endsect]
[section Element Access]
[section `constexpr const_reference operator[]( size_type pos ) const noexcept;`]
* *Requires:* `pos < size()`.
* *Returns:* `data()[ pos ]`.
[endsect]
[section `constexpr const_reference at( size_type pos ) const;`]
* *Returns:* `data()[ pos ]`.
* *Throws:* `std::out_of_range` when `pos >= size()`.
[endsect]
[section `constexpr const_reference front() const noexcept;`]
* *Requires:* `!empty()`.
* *Returns:* `data()[ 0 ]`.
[endsect]
[section `constexpr const_reference back() const noexcept;`]
* *Requires:* `!empty()`.
* *Returns:* `data()[ size() - 1 ]`.
[endsect]
[section `constexpr const_pointer data() const noexcept;`]
* *Returns:* a pointer to the beginning of the referenced character sequence.
[endsect]
[endsect]
[section Modifiers]
[section `constexpr void remove_prefix( size_type n ) noexcept;`]
* *Requires:* `n <= size()`.
* *Effects:* advances `data()` by `n` and decreases `size()` by `n`.
[endsect]
[section `constexpr void remove_suffix( size_type n ) noexcept;`]
* *Requires:* `n <= size()`.
* *Effects:* decreases `size()` by `n`.
[endsect]
[section `constexpr void swap( basic_string_view& s ) noexcept;`]
* *Effects:* exchanges the contents of `*this` and `s`.
[endsect]
[endsect]
[section String Operations]
[section copy]
[section `constexpr size_type copy( Ch* s, size_type n, size_type pos = 0 ) const;`]
* *Effects:* copies to `s` the contents of `substr( pos, n )`.
* *Throws:* `std::out_of_range` when `pos >= size()`.
[endsect]
[endsect]
[section substr]
[section `constexpr basic_string_view substr( size_type pos = 0, size_type n = npos ) const;`]
* *Returns:* `basic_string_view( data() + pos, std::min( size() - pos, n ) )`.
* *Throws:* `std::out_of_range` when `pos >= size()`.
[endsect]
[endsect]
[section compare]
[section `constexpr int compare( basic_string_view str ) const noexcept;`]
* *Returns:*
* if `traits_type::compare( data(), str.data(), std::min( size(), str.size() ) )` is not zero, returns it. Otherwise,
* if `size() < str.size()`, returns a negative number. Otherwise,
* if `size() > str.size()`, returns a positive number. Otherwise,
* returns 0.
[endsect]
[section `constexpr int compare( size_type pos1, size_type n1, basic_string_view str ) const;`]
* *Returns:* `substr( pos1, n1 ).compare( str )`.
[endsect]
[section `constexpr int compare( size_type pos1, size_type n1, basic_string_view str, size_type pos2, size_type n2 ) const;`]
* *Returns:* `substr( pos1, n1 ).compare( str.substr( pos2, n2 ) )`.
[endsect]
[section `constexpr int compare( Ch const* s ) const noexcept;`]
* *Returns:* `compare( basic_string_view( s ) )`.
[endsect]
[section `constexpr int compare( size_type pos1, size_type n1, Ch const* s ) const;`]
* *Returns:* `substr( pos1, n1 ).compare( basic_string_view( s ) )`.
[endsect]
[section `constexpr int compare( size_type pos1, size_type n1, Ch const* s, size_type n2 ) const;`]
* *Returns:* `substr( pos1, n1 ).compare( basic_string_view( s, n2 ) )`.
[endsect]
[endsect]
[section starts_with]
[section `constexpr bool starts_with( basic_string_view x ) const noexcept;`]
* *Returns:* `substr( 0, x.size() ) == x`.
[endsect]
[section `constexpr bool starts_with( Ch x ) const noexcept;`]
* *Returns:* `starts_with( basic_string_view( &x, 1 ) )`.
[endsect]
[section `constexpr bool starts_with( Ch const* x ) const noexcept;`]
* *Returns:* `starts_with( basic_string_view( x ) )`.
[endsect]
[endsect]
[section ends_with]
[section `constexpr bool ends_with( basic_string_view x ) const noexcept;`]
* *Returns:* `size() >= x.size() && substr( size() - x.size(), x.size() ) == x`.
[endsect]
[section `constexpr bool ends_with( Ch x ) const noexcept;`]
* *Returns:* `ends_with( basic_string_view( &x, 1 ) )`.
[endsect]
[section `constexpr bool ends_with( Ch const* x ) const noexcept;`]
* *Returns:* `ends_with( basic_string_view( x ) )`.
[endsect]
[endsect]
[endsect]
[section Searching]
[section find]
[section `constexpr size_type find( basic_string_view str, size_type pos = 0 ) const noexcept;`]
* *Returns:* The lowest position `i` such that `i >= pos` and `substr( i, str.size() ) == str`, or `npos` if such a position doesn't exist.
[endsect]
[section `constexpr size_type find( Ch c, size_type pos = 0 ) const noexcept;`]
* *Returns:* `find( basic_string_view( &c, 1 ), pos )`.
[endsect]
[section `constexpr size_type find( Ch const* s, size_type pos, size_type n ) const noexcept;`]
* *Returns:* `find( basic_string_view( s, n ), pos )`.
[endsect]
[section `constexpr size_type find( Ch const* s, size_type pos = 0 ) const noexcept;`]
* *Returns:* `find( basic_string_view( s ), pos )`.
[endsect]
[endsect]
[section rfind]
[section `constexpr size_type rfind( basic_string_view str, size_type pos = npos ) const noexcept;`]
* *Returns:* The highest position `i` such that `i <= pos` and `substr( i, str.size() ) == str`, or `npos` if such a position doesn't exist.
[endsect]
[section `constexpr size_type rfind( Ch c, size_type pos = npos ) const noexcept;`]
* *Returns:* `rfind( basic_string_view( &c, 1 ), pos )`.
[endsect]
[section `constexpr size_type rfind( Ch const* s, size_type pos, size_type n ) const noexcept;`]
* *Returns:* `rfind( basic_string_view( s, n ), pos )`.
[endsect]
[section `constexpr size_type rfind( Ch const* s, size_type pos = npos ) const noexcept;`]
* *Returns:* `rfind( basic_string_view( s ), pos )`.
[endsect]
[endsect]
[section find_first_of]
[section `constexpr size_type find_first_of( basic_string_view str, size_type pos = 0 ) const noexcept;`]
* *Returns:* The lowest position `i` such that `i >= pos` and the character at position `i` is equal to one of the characters in `str`, or `npos` if such a position doesn't exist.
[endsect]
[section `constexpr size_type find_first_of( Ch c, size_type pos = 0 ) const noexcept;`]
* *Returns:* `find_first_of( basic_string_view( &c, 1 ), pos )`.
[endsect]
[section `constexpr size_type find_first_of( Ch const* s, size_type pos, size_type n ) const noexcept;`]
* *Returns:* `find_first_of( basic_string_view( s, n ), pos )`.
[endsect]
[section `constexpr size_type find_first_of( Ch const* s, size_type pos = 0 ) const noexcept;`]
* *Returns:* `find_first_of( basic_string_view( s ), pos )`.
[endsect]
[endsect]
[section find_last_of]
[section `constexpr size_type find_last_of( basic_string_view str, size_type pos = npos ) const noexcept;`]
* *Returns:* The highest position `i` such that `i <= pos` and the character at position `i` is equal to one of the characters in `str`, or `npos` if such a position doesn't exist.
[endsect]
[section `constexpr size_type find_last_of( Ch c, size_type pos = npos ) const noexcept;`]
* *Returns:* `find_last_of( basic_string_view( &c, 1 ), pos )`.
[endsect]
[section `constexpr size_type find_last_of( Ch const* s, size_type pos, size_type n ) const noexcept;`]
* *Returns:* `find_last_of( basic_string_view( s, n ), pos )`.
[endsect]
[section `constexpr size_type find_last_of( Ch const* s, size_type pos = npos ) const noexcept;`]
* *Returns:* `find_last_of( basic_string_view( s ), pos )`.
[endsect]
[endsect]
[section find_first_not_of]
[section `constexpr size_type find_first_not_of( basic_string_view str, size_type pos = 0 ) const noexcept;`]
* *Returns:* The lowest position `i` such that `i >= pos` and the character at position `i` is not equal to one of the characters in `str`, or `npos` if such a position doesn't exist.
[endsect]
[section `constexpr size_type find_first_not_of( Ch c, size_type pos = 0 ) const noexcept;`]
* *Returns:* `find_first_not_of( basic_string_view( &c, 1 ), pos )`.
[endsect]
[section `constexpr size_type find_first_not_of( Ch const* s, size_type pos, size_type n ) const noexcept;`]
* *Returns:* `find_first_not_of( basic_string_view( s, n ), pos )`.
[endsect]
[section `constexpr size_type find_first_not_of( Ch const* s, size_type pos = 0 ) const noexcept;`]
* *Returns:* `find_first_not_of( basic_string_view( s ), pos )`.
[endsect]
[endsect]
[section find_last_not_of]
[section `constexpr size_type find_last_not_of( basic_string_view str, size_type pos = npos ) const noexcept;`]
* *Returns:* The highest position `i` such that `i <= pos` and the character at position `i` is not equal to one of the characters in `str`, or `npos` if such a position doesn't exist.
[endsect]
[section `constexpr size_type find_last_not_of( Ch c, size_type pos = npos ) const noexcept;`]
* *Returns:* `find_last_not_of( basic_string_view( &c, 1 ), pos )`.
[endsect]
[section `constexpr size_type find_last_not_of( Ch const* s, size_type pos, size_type n ) const noexcept;`]
* *Returns:* `find_last_not_of( basic_string_view( s, n ), pos )`.
[endsect]
[section `constexpr size_type find_last_not_of( Ch const* s, size_type pos = npos ) const noexcept;`]
* *Returns:* `find_last_not_of( basic_string_view( s ), pos )`.
[endsect]
[endsect]
[section contains]
[section `constexpr bool contains( basic_string_view sv ) const noexcept;`]
* *Returns:* `find( sv ) != npos`.
[endsect]
[section `constexpr bool contains( Ch c ) const noexcept;`]
* *Returns:* `find( c ) != npos`.
[endsect]
[section `constexpr bool contains( Ch const* s ) const noexcept;`]
* *Returns:* `find( s ) != npos`.
[endsect]
[endsect]
[endsect]
[section Relational Operators]
[section `constexpr friend bool operator==( basic_string_view sv1, basic_string_view sv2 ) noexcept;`]
* *Returns:* `sv1.compare( sv2 ) == 0`.
[endsect]
[section `constexpr friend bool operator!=( basic_string_view sv1, basic_string_view sv2 ) noexcept;`]
* *Returns:* `sv1.compare( sv2 ) != 0`.
[endsect]
[section `constexpr friend bool operator<( basic_string_view sv1, basic_string_view sv2 ) noexcept;`]
* *Returns:* `sv1.compare( sv2 ) < 0`.
[endsect]
[section `constexpr friend bool operator<=( basic_string_view sv1, basic_string_view sv2 ) noexcept;`]
* *Returns:* `sv1.compare( sv2 ) <= 0`.
[endsect]
[section `constexpr friend bool operator>( basic_string_view sv1, basic_string_view sv2 ) noexcept;`]
* *Returns:* `sv1.compare( sv2 ) > 0`.
[endsect]
[section `constexpr friend bool operator>=( basic_string_view sv1, basic_string_view sv2 ) noexcept;`]
* *Returns:* `sv1.compare( sv2 ) >= 0`.
[endsect]
[endsect]
[section Stream Inserter]
[section `template<class Ch> std::basic_ostream<Ch>& operator<<( std::basic_ostream<Ch>& os, basic_string_view<Ch> str );`]
* *Effects:* equivalent to `os << x`, where `x` is a pointer to a null-terminated character sequence with the same contents as `str`.
[endsect]
[endsect]
[endsect]
[endsect]