mirrored from git://gcc.gnu.org/git/gcc.git
/
basic_string.h
4746 lines (4367 loc) · 162 KB
/
basic_string.h
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// Components for manipulating sequences of characters -*- C++ -*-
// Copyright (C) 1997-2024 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.
// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
// <http://www.gnu.org/licenses/>.
/** @file bits/basic_string.h
* This is an internal header file, included by other library headers.
* Do not attempt to use it directly. @headername{string}
*/
//
// ISO C++ 14882: 21 Strings library
//
#ifndef _BASIC_STRING_H
#define _BASIC_STRING_H 1
#pragma GCC system_header
#include <ext/alloc_traits.h>
#include <debug/debug.h>
#if __cplusplus >= 201103L
#include <initializer_list>
#endif
#if __cplusplus >= 201703L
# include <string_view>
#endif
#if __cplusplus > 202302L
# include <charconv>
#endif
#include <bits/version.h>
#if ! _GLIBCXX_USE_CXX11_ABI
# include "cow_string.h"
#else
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
_GLIBCXX_BEGIN_NAMESPACE_CXX11
/**
* @class basic_string basic_string.h <string>
* @brief Managing sequences of characters and character-like objects.
*
* @ingroup strings
* @ingroup sequences
* @headerfile string
* @since C++98
*
* @tparam _CharT Type of character
* @tparam _Traits Traits for character type, defaults to
* char_traits<_CharT>.
* @tparam _Alloc Allocator type, defaults to allocator<_CharT>.
*
* Meets the requirements of a <a href="tables.html#65">container</a>, a
* <a href="tables.html#66">reversible container</a>, and a
* <a href="tables.html#67">sequence</a>. Of the
* <a href="tables.html#68">optional sequence requirements</a>, only
* @c push_back, @c at, and @c %array access are supported.
*/
template<typename _CharT, typename _Traits, typename _Alloc>
class basic_string
{
#if __cplusplus >= 202002L
static_assert(is_same_v<_CharT, typename _Traits::char_type>);
static_assert(is_same_v<_CharT, typename _Alloc::value_type>);
using _Char_alloc_type = _Alloc;
#else
typedef typename __gnu_cxx::__alloc_traits<_Alloc>::template
rebind<_CharT>::other _Char_alloc_type;
#endif
typedef __gnu_cxx::__alloc_traits<_Char_alloc_type> _Alloc_traits;
// Types:
public:
typedef _Traits traits_type;
typedef typename _Traits::char_type value_type;
typedef _Char_alloc_type allocator_type;
typedef typename _Alloc_traits::size_type size_type;
typedef typename _Alloc_traits::difference_type difference_type;
typedef typename _Alloc_traits::reference reference;
typedef typename _Alloc_traits::const_reference const_reference;
typedef typename _Alloc_traits::pointer pointer;
typedef typename _Alloc_traits::const_pointer const_pointer;
typedef __gnu_cxx::__normal_iterator<pointer, basic_string> iterator;
typedef __gnu_cxx::__normal_iterator<const_pointer, basic_string>
const_iterator;
typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
typedef std::reverse_iterator<iterator> reverse_iterator;
/// Value returned by various member functions when they fail.
static const size_type npos = static_cast<size_type>(-1);
protected:
// type used for positions in insert, erase etc.
#if __cplusplus < 201103L
typedef iterator __const_iterator;
#else
typedef const_iterator __const_iterator;
#endif
private:
static _GLIBCXX20_CONSTEXPR pointer
_S_allocate(_Char_alloc_type& __a, size_type __n)
{
pointer __p = _Alloc_traits::allocate(__a, __n);
#if __glibcxx_constexpr_string >= 201907L
// std::char_traits begins the lifetime of characters,
// but custom traits might not, so do it here.
if constexpr (!is_same_v<_Traits, char_traits<_CharT>>)
if (std::__is_constant_evaluated())
// Begin the lifetime of characters in allocated storage.
for (size_type __i = 0; __i < __n; ++__i)
std::construct_at(__builtin_addressof(__p[__i]));
#endif
return __p;
}
#if __cplusplus >= 201703L
// A helper type for avoiding boiler-plate.
typedef basic_string_view<_CharT, _Traits> __sv_type;
template<typename _Tp, typename _Res>
using _If_sv = enable_if_t<
__and_<is_convertible<const _Tp&, __sv_type>,
__not_<is_convertible<const _Tp*, const basic_string*>>,
__not_<is_convertible<const _Tp&, const _CharT*>>>::value,
_Res>;
// Allows an implicit conversion to __sv_type.
_GLIBCXX20_CONSTEXPR
static __sv_type
_S_to_string_view(__sv_type __svt) noexcept
{ return __svt; }
// Wraps a string_view by explicit conversion and thus
// allows to add an internal constructor that does not
// participate in overload resolution when a string_view
// is provided.
struct __sv_wrapper
{
_GLIBCXX20_CONSTEXPR explicit
__sv_wrapper(__sv_type __sv) noexcept : _M_sv(__sv) { }
__sv_type _M_sv;
};
/**
* @brief Only internally used: Construct string from a string view
* wrapper.
* @param __svw string view wrapper.
* @param __a Allocator to use.
*/
_GLIBCXX20_CONSTEXPR
explicit
basic_string(__sv_wrapper __svw, const _Alloc& __a)
: basic_string(__svw._M_sv.data(), __svw._M_sv.size(), __a) { }
#endif
// Use empty-base optimization: http://www.cantrip.org/emptyopt.html
struct _Alloc_hider : allocator_type // TODO check __is_final
{
#if __cplusplus < 201103L
_Alloc_hider(pointer __dat, const _Alloc& __a = _Alloc())
: allocator_type(__a), _M_p(__dat) { }
#else
_GLIBCXX20_CONSTEXPR
_Alloc_hider(pointer __dat, const _Alloc& __a)
: allocator_type(__a), _M_p(__dat) { }
_GLIBCXX20_CONSTEXPR
_Alloc_hider(pointer __dat, _Alloc&& __a = _Alloc())
: allocator_type(std::move(__a)), _M_p(__dat) { }
#endif
pointer _M_p; // The actual data.
};
_Alloc_hider _M_dataplus;
size_type _M_string_length;
enum { _S_local_capacity = 15 / sizeof(_CharT) };
union
{
_CharT _M_local_buf[_S_local_capacity + 1];
size_type _M_allocated_capacity;
};
_GLIBCXX20_CONSTEXPR
void
_M_data(pointer __p)
{ _M_dataplus._M_p = __p; }
_GLIBCXX20_CONSTEXPR
void
_M_length(size_type __length)
{ _M_string_length = __length; }
_GLIBCXX20_CONSTEXPR
pointer
_M_data() const
{ return _M_dataplus._M_p; }
_GLIBCXX20_CONSTEXPR
pointer
_M_local_data()
{
#if __cplusplus >= 201103L
return std::pointer_traits<pointer>::pointer_to(*_M_local_buf);
#else
return pointer(_M_local_buf);
#endif
}
_GLIBCXX20_CONSTEXPR
const_pointer
_M_local_data() const
{
#if __cplusplus >= 201103L
return std::pointer_traits<const_pointer>::pointer_to(*_M_local_buf);
#else
return const_pointer(_M_local_buf);
#endif
}
_GLIBCXX20_CONSTEXPR
void
_M_capacity(size_type __capacity)
{ _M_allocated_capacity = __capacity; }
_GLIBCXX20_CONSTEXPR
void
_M_set_length(size_type __n)
{
_M_length(__n);
traits_type::assign(_M_data()[__n], _CharT());
}
_GLIBCXX20_CONSTEXPR
bool
_M_is_local() const
{
if (_M_data() == _M_local_data())
{
if (_M_string_length > _S_local_capacity)
__builtin_unreachable();
return true;
}
return false;
}
// Create & Destroy
_GLIBCXX20_CONSTEXPR
pointer
_M_create(size_type&, size_type);
_GLIBCXX20_CONSTEXPR
void
_M_dispose()
{
if (!_M_is_local())
_M_destroy(_M_allocated_capacity);
}
_GLIBCXX20_CONSTEXPR
void
_M_destroy(size_type __size) throw()
{ _Alloc_traits::deallocate(_M_get_allocator(), _M_data(), __size + 1); }
#if __cplusplus < 201103L || defined _GLIBCXX_DEFINING_STRING_INSTANTIATIONS
// _M_construct_aux is used to implement the 21.3.1 para 15 which
// requires special behaviour if _InIterator is an integral type
template<typename _InIterator>
void
_M_construct_aux(_InIterator __beg, _InIterator __end,
std::__false_type)
{
typedef typename iterator_traits<_InIterator>::iterator_category _Tag;
_M_construct(__beg, __end, _Tag());
}
// _GLIBCXX_RESOLVE_LIB_DEFECTS
// 438. Ambiguity in the "do the right thing" clause
template<typename _Integer>
void
_M_construct_aux(_Integer __beg, _Integer __end, std::__true_type)
{ _M_construct_aux_2(static_cast<size_type>(__beg), __end); }
void
_M_construct_aux_2(size_type __req, _CharT __c)
{ _M_construct(__req, __c); }
#endif
// For Input Iterators, used in istreambuf_iterators, etc.
template<typename _InIterator>
_GLIBCXX20_CONSTEXPR
void
_M_construct(_InIterator __beg, _InIterator __end,
std::input_iterator_tag);
// For forward_iterators up to random_access_iterators, used for
// string::iterator, _CharT*, etc.
template<typename _FwdIterator>
_GLIBCXX20_CONSTEXPR
void
_M_construct(_FwdIterator __beg, _FwdIterator __end,
std::forward_iterator_tag);
_GLIBCXX20_CONSTEXPR
void
_M_construct(size_type __req, _CharT __c);
_GLIBCXX20_CONSTEXPR
allocator_type&
_M_get_allocator()
{ return _M_dataplus; }
_GLIBCXX20_CONSTEXPR
const allocator_type&
_M_get_allocator() const
{ return _M_dataplus; }
// Ensure that _M_local_buf is the active member of the union.
__attribute__((__always_inline__))
_GLIBCXX14_CONSTEXPR
void
_M_init_local_buf() _GLIBCXX_NOEXCEPT
{
#if __glibcxx_is_constant_evaluated
if (std::is_constant_evaluated())
for (size_type __i = 0; __i <= _S_local_capacity; ++__i)
_M_local_buf[__i] = _CharT();
#endif
}
__attribute__((__always_inline__))
_GLIBCXX14_CONSTEXPR
pointer
_M_use_local_data() _GLIBCXX_NOEXCEPT
{
#if __cpp_lib_is_constant_evaluated
_M_init_local_buf();
#endif
return _M_local_data();
}
private:
#ifdef _GLIBCXX_DISAMBIGUATE_REPLACE_INST
// The explicit instantiations in misc-inst.cc require this due to
// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64063
template<typename _Tp, bool _Requires =
!__are_same<_Tp, _CharT*>::__value
&& !__are_same<_Tp, const _CharT*>::__value
&& !__are_same<_Tp, iterator>::__value
&& !__are_same<_Tp, const_iterator>::__value>
struct __enable_if_not_native_iterator
{ typedef basic_string& __type; };
template<typename _Tp>
struct __enable_if_not_native_iterator<_Tp, false> { };
#endif
_GLIBCXX20_CONSTEXPR
size_type
_M_check(size_type __pos, const char* __s) const
{
if (__pos > this->size())
__throw_out_of_range_fmt(__N("%s: __pos (which is %zu) > "
"this->size() (which is %zu)"),
__s, __pos, this->size());
return __pos;
}
_GLIBCXX20_CONSTEXPR
void
_M_check_length(size_type __n1, size_type __n2, const char* __s) const
{
if (this->max_size() - (this->size() - __n1) < __n2)
__throw_length_error(__N(__s));
}
// NB: _M_limit doesn't check for a bad __pos value.
_GLIBCXX20_CONSTEXPR
size_type
_M_limit(size_type __pos, size_type __off) const _GLIBCXX_NOEXCEPT
{
const bool __testoff = __off < this->size() - __pos;
return __testoff ? __off : this->size() - __pos;
}
// True if _Rep and source do not overlap.
bool
_M_disjunct(const _CharT* __s) const _GLIBCXX_NOEXCEPT
{
return (less<const _CharT*>()(__s, _M_data())
|| less<const _CharT*>()(_M_data() + this->size(), __s));
}
// When __n = 1 way faster than the general multichar
// traits_type::copy/move/assign.
_GLIBCXX20_CONSTEXPR
static void
_S_copy(_CharT* __d, const _CharT* __s, size_type __n)
{
if (__n == 1)
traits_type::assign(*__d, *__s);
else
traits_type::copy(__d, __s, __n);
}
_GLIBCXX20_CONSTEXPR
static void
_S_move(_CharT* __d, const _CharT* __s, size_type __n)
{
if (__n == 1)
traits_type::assign(*__d, *__s);
else
traits_type::move(__d, __s, __n);
}
_GLIBCXX20_CONSTEXPR
static void
_S_assign(_CharT* __d, size_type __n, _CharT __c)
{
if (__n == 1)
traits_type::assign(*__d, __c);
else
traits_type::assign(__d, __n, __c);
}
// _S_copy_chars is a separate template to permit specialization
// to optimize for the common case of pointers as iterators.
template<class _Iterator>
_GLIBCXX20_CONSTEXPR
static void
_S_copy_chars(_CharT* __p, _Iterator __k1, _Iterator __k2)
{
for (; __k1 != __k2; ++__k1, (void)++__p)
traits_type::assign(*__p, *__k1); // These types are off.
}
_GLIBCXX20_CONSTEXPR
static void
_S_copy_chars(_CharT* __p, iterator __k1, iterator __k2) _GLIBCXX_NOEXCEPT
{ _S_copy_chars(__p, __k1.base(), __k2.base()); }
_GLIBCXX20_CONSTEXPR
static void
_S_copy_chars(_CharT* __p, const_iterator __k1, const_iterator __k2)
_GLIBCXX_NOEXCEPT
{ _S_copy_chars(__p, __k1.base(), __k2.base()); }
_GLIBCXX20_CONSTEXPR
static void
_S_copy_chars(_CharT* __p, _CharT* __k1, _CharT* __k2) _GLIBCXX_NOEXCEPT
{ _S_copy(__p, __k1, __k2 - __k1); }
_GLIBCXX20_CONSTEXPR
static void
_S_copy_chars(_CharT* __p, const _CharT* __k1, const _CharT* __k2)
_GLIBCXX_NOEXCEPT
{ _S_copy(__p, __k1, __k2 - __k1); }
_GLIBCXX20_CONSTEXPR
static int
_S_compare(size_type __n1, size_type __n2) _GLIBCXX_NOEXCEPT
{
const difference_type __d = difference_type(__n1 - __n2);
if (__d > __gnu_cxx::__numeric_traits<int>::__max)
return __gnu_cxx::__numeric_traits<int>::__max;
else if (__d < __gnu_cxx::__numeric_traits<int>::__min)
return __gnu_cxx::__numeric_traits<int>::__min;
else
return int(__d);
}
_GLIBCXX20_CONSTEXPR
void
_M_assign(const basic_string&);
_GLIBCXX20_CONSTEXPR
void
_M_mutate(size_type __pos, size_type __len1, const _CharT* __s,
size_type __len2);
_GLIBCXX20_CONSTEXPR
void
_M_erase(size_type __pos, size_type __n);
public:
// Construct/copy/destroy:
// NB: We overload ctors in some cases instead of using default
// arguments, per 17.4.4.4 para. 2 item 2.
/**
* @brief Default constructor creates an empty string.
*/
_GLIBCXX20_CONSTEXPR
basic_string()
_GLIBCXX_NOEXCEPT_IF(is_nothrow_default_constructible<_Alloc>::value)
: _M_dataplus(_M_local_data())
{
_M_init_local_buf();
_M_set_length(0);
}
/**
* @brief Construct an empty string using allocator @a a.
*/
_GLIBCXX20_CONSTEXPR
explicit
basic_string(const _Alloc& __a) _GLIBCXX_NOEXCEPT
: _M_dataplus(_M_local_data(), __a)
{
_M_init_local_buf();
_M_set_length(0);
}
/**
* @brief Construct string with copy of value of @a __str.
* @param __str Source string.
*/
_GLIBCXX20_CONSTEXPR
basic_string(const basic_string& __str)
: _M_dataplus(_M_local_data(),
_Alloc_traits::_S_select_on_copy(__str._M_get_allocator()))
{
_M_construct(__str._M_data(), __str._M_data() + __str.length(),
std::forward_iterator_tag());
}
// _GLIBCXX_RESOLVE_LIB_DEFECTS
// 2583. no way to supply an allocator for basic_string(str, pos)
/**
* @brief Construct string as copy of a substring.
* @param __str Source string.
* @param __pos Index of first character to copy from.
* @param __a Allocator to use.
*/
_GLIBCXX20_CONSTEXPR
basic_string(const basic_string& __str, size_type __pos,
const _Alloc& __a = _Alloc())
: _M_dataplus(_M_local_data(), __a)
{
const _CharT* __start = __str._M_data()
+ __str._M_check(__pos, "basic_string::basic_string");
_M_construct(__start, __start + __str._M_limit(__pos, npos),
std::forward_iterator_tag());
}
/**
* @brief Construct string as copy of a substring.
* @param __str Source string.
* @param __pos Index of first character to copy from.
* @param __n Number of characters to copy.
*/
_GLIBCXX20_CONSTEXPR
basic_string(const basic_string& __str, size_type __pos,
size_type __n)
: _M_dataplus(_M_local_data())
{
const _CharT* __start = __str._M_data()
+ __str._M_check(__pos, "basic_string::basic_string");
_M_construct(__start, __start + __str._M_limit(__pos, __n),
std::forward_iterator_tag());
}
/**
* @brief Construct string as copy of a substring.
* @param __str Source string.
* @param __pos Index of first character to copy from.
* @param __n Number of characters to copy.
* @param __a Allocator to use.
*/
_GLIBCXX20_CONSTEXPR
basic_string(const basic_string& __str, size_type __pos,
size_type __n, const _Alloc& __a)
: _M_dataplus(_M_local_data(), __a)
{
const _CharT* __start
= __str._M_data() + __str._M_check(__pos, "string::string");
_M_construct(__start, __start + __str._M_limit(__pos, __n),
std::forward_iterator_tag());
}
/**
* @brief Construct string initialized by a character %array.
* @param __s Source character %array.
* @param __n Number of characters to copy.
* @param __a Allocator to use (default is default allocator).
*
* NB: @a __s must have at least @a __n characters, '\\0'
* has no special meaning.
*/
_GLIBCXX20_CONSTEXPR
basic_string(const _CharT* __s, size_type __n,
const _Alloc& __a = _Alloc())
: _M_dataplus(_M_local_data(), __a)
{
// NB: Not required, but considered best practice.
if (__s == 0 && __n > 0)
std::__throw_logic_error(__N("basic_string: "
"construction from null is not valid"));
_M_construct(__s, __s + __n, std::forward_iterator_tag());
}
/**
* @brief Construct string as copy of a C string.
* @param __s Source C string.
* @param __a Allocator to use (default is default allocator).
*/
#if __cpp_deduction_guides && ! defined _GLIBCXX_DEFINING_STRING_INSTANTIATIONS
// _GLIBCXX_RESOLVE_LIB_DEFECTS
// 3076. basic_string CTAD ambiguity
template<typename = _RequireAllocator<_Alloc>>
#endif
_GLIBCXX20_CONSTEXPR
basic_string(const _CharT* __s, const _Alloc& __a = _Alloc())
: _M_dataplus(_M_local_data(), __a)
{
// NB: Not required, but considered best practice.
if (__s == 0)
std::__throw_logic_error(__N("basic_string: "
"construction from null is not valid"));
const _CharT* __end = __s + traits_type::length(__s);
_M_construct(__s, __end, forward_iterator_tag());
}
/**
* @brief Construct string as multiple characters.
* @param __n Number of characters.
* @param __c Character to use.
* @param __a Allocator to use (default is default allocator).
*/
#if __cpp_deduction_guides && ! defined _GLIBCXX_DEFINING_STRING_INSTANTIATIONS
// _GLIBCXX_RESOLVE_LIB_DEFECTS
// 3076. basic_string CTAD ambiguity
template<typename = _RequireAllocator<_Alloc>>
#endif
_GLIBCXX20_CONSTEXPR
basic_string(size_type __n, _CharT __c, const _Alloc& __a = _Alloc())
: _M_dataplus(_M_local_data(), __a)
{ _M_construct(__n, __c); }
#if __cplusplus >= 201103L
/**
* @brief Move construct string.
* @param __str Source string.
*
* The newly-created string contains the exact contents of @a __str.
* @a __str is a valid, but unspecified string.
*/
_GLIBCXX20_CONSTEXPR
basic_string(basic_string&& __str) noexcept
: _M_dataplus(_M_local_data(), std::move(__str._M_get_allocator()))
{
if (__str._M_is_local())
{
_M_init_local_buf();
traits_type::copy(_M_local_buf, __str._M_local_buf,
__str.length() + 1);
}
else
{
_M_data(__str._M_data());
_M_capacity(__str._M_allocated_capacity);
}
// Must use _M_length() here not _M_set_length() because
// basic_stringbuf relies on writing into unallocated capacity so
// we mess up the contents if we put a '\0' in the string.
_M_length(__str.length());
__str._M_data(__str._M_use_local_data());
__str._M_set_length(0);
}
/**
* @brief Construct string from an initializer %list.
* @param __l std::initializer_list of characters.
* @param __a Allocator to use (default is default allocator).
*/
_GLIBCXX20_CONSTEXPR
basic_string(initializer_list<_CharT> __l, const _Alloc& __a = _Alloc())
: _M_dataplus(_M_local_data(), __a)
{ _M_construct(__l.begin(), __l.end(), std::forward_iterator_tag()); }
_GLIBCXX20_CONSTEXPR
basic_string(const basic_string& __str, const _Alloc& __a)
: _M_dataplus(_M_local_data(), __a)
{ _M_construct(__str.begin(), __str.end(), std::forward_iterator_tag()); }
_GLIBCXX20_CONSTEXPR
basic_string(basic_string&& __str, const _Alloc& __a)
noexcept(_Alloc_traits::_S_always_equal())
: _M_dataplus(_M_local_data(), __a)
{
if (__str._M_is_local())
{
_M_init_local_buf();
traits_type::copy(_M_local_buf, __str._M_local_buf,
__str.length() + 1);
_M_length(__str.length());
__str._M_set_length(0);
}
else if (_Alloc_traits::_S_always_equal()
|| __str.get_allocator() == __a)
{
_M_data(__str._M_data());
_M_length(__str.length());
_M_capacity(__str._M_allocated_capacity);
__str._M_data(__str._M_use_local_data());
__str._M_set_length(0);
}
else
_M_construct(__str.begin(), __str.end(), std::forward_iterator_tag());
}
#endif // C++11
#if __cplusplus >= 202100L
basic_string(nullptr_t) = delete;
basic_string& operator=(nullptr_t) = delete;
#endif // C++23
/**
* @brief Construct string as copy of a range.
* @param __beg Start of range.
* @param __end End of range.
* @param __a Allocator to use (default is default allocator).
*/
#if __cplusplus >= 201103L
template<typename _InputIterator,
typename = std::_RequireInputIter<_InputIterator>>
#else
template<typename _InputIterator>
#endif
_GLIBCXX20_CONSTEXPR
basic_string(_InputIterator __beg, _InputIterator __end,
const _Alloc& __a = _Alloc())
: _M_dataplus(_M_local_data(), __a), _M_string_length(0)
{
#if __cplusplus >= 201103L
_M_construct(__beg, __end, std::__iterator_category(__beg));
#else
typedef typename std::__is_integer<_InputIterator>::__type _Integral;
_M_construct_aux(__beg, __end, _Integral());
#endif
}
#if __cplusplus >= 201703L
/**
* @brief Construct string from a substring of a string_view.
* @param __t Source object convertible to string view.
* @param __pos The index of the first character to copy from __t.
* @param __n The number of characters to copy from __t.
* @param __a Allocator to use.
*/
template<typename _Tp,
typename = enable_if_t<is_convertible_v<const _Tp&, __sv_type>>>
_GLIBCXX20_CONSTEXPR
basic_string(const _Tp& __t, size_type __pos, size_type __n,
const _Alloc& __a = _Alloc())
: basic_string(_S_to_string_view(__t).substr(__pos, __n), __a) { }
/**
* @brief Construct string from a string_view.
* @param __t Source object convertible to string view.
* @param __a Allocator to use (default is default allocator).
*/
template<typename _Tp, typename = _If_sv<_Tp, void>>
_GLIBCXX20_CONSTEXPR
explicit
basic_string(const _Tp& __t, const _Alloc& __a = _Alloc())
: basic_string(__sv_wrapper(_S_to_string_view(__t)), __a) { }
#endif // C++17
/**
* @brief Destroy the string instance.
*/
_GLIBCXX20_CONSTEXPR
~basic_string()
{ _M_dispose(); }
/**
* @brief Assign the value of @a str to this string.
* @param __str Source string.
*/
_GLIBCXX20_CONSTEXPR
basic_string&
operator=(const basic_string& __str)
{
return this->assign(__str);
}
/**
* @brief Copy contents of @a s into this string.
* @param __s Source null-terminated string.
*/
_GLIBCXX20_CONSTEXPR
basic_string&
operator=(const _CharT* __s)
{ return this->assign(__s); }
/**
* @brief Set value to string of length 1.
* @param __c Source character.
*
* Assigning to a character makes this string length 1 and
* (*this)[0] == @a c.
*/
_GLIBCXX20_CONSTEXPR
basic_string&
operator=(_CharT __c)
{
this->assign(1, __c);
return *this;
}
#if __cplusplus >= 201103L
/**
* @brief Move assign the value of @a str to this string.
* @param __str Source string.
*
* The contents of @a str are moved into this string (without copying).
* @a str is a valid, but unspecified string.
*/
// _GLIBCXX_RESOLVE_LIB_DEFECTS
// 2063. Contradictory requirements for string move assignment
_GLIBCXX20_CONSTEXPR
basic_string&
operator=(basic_string&& __str)
noexcept(_Alloc_traits::_S_nothrow_move())
{
const bool __equal_allocs = _Alloc_traits::_S_always_equal()
|| _M_get_allocator() == __str._M_get_allocator();
if (!_M_is_local() && _Alloc_traits::_S_propagate_on_move_assign()
&& !__equal_allocs)
{
// Destroy existing storage before replacing allocator.
_M_destroy(_M_allocated_capacity);
_M_data(_M_local_data());
_M_set_length(0);
}
// Replace allocator if POCMA is true.
std::__alloc_on_move(_M_get_allocator(), __str._M_get_allocator());
if (__str._M_is_local())
{
// We've always got room for a short string, just copy it
// (unless this is a self-move, because that would violate the
// char_traits::copy precondition that the ranges don't overlap).
if (__builtin_expect(std::__addressof(__str) != this, true))
{
if (__str.size())
this->_S_copy(_M_data(), __str._M_data(), __str.size());
_M_set_length(__str.size());
}
}
else if (_Alloc_traits::_S_propagate_on_move_assign() || __equal_allocs)
{
// Just move the allocated pointer, our allocator can free it.
pointer __data = nullptr;
size_type __capacity;
if (!_M_is_local())
{
if (__equal_allocs)
{
// __str can reuse our existing storage.
__data = _M_data();
__capacity = _M_allocated_capacity;
}
else // __str can't use it, so free it.
_M_destroy(_M_allocated_capacity);
}
_M_data(__str._M_data());
_M_length(__str.length());
_M_capacity(__str._M_allocated_capacity);
if (__data)
{
__str._M_data(__data);
__str._M_capacity(__capacity);
}
else
__str._M_data(__str._M_use_local_data());
}
else // Need to do a deep copy
assign(__str);
__str.clear();
return *this;
}
/**
* @brief Set value to string constructed from initializer %list.
* @param __l std::initializer_list.
*/
_GLIBCXX20_CONSTEXPR
basic_string&
operator=(initializer_list<_CharT> __l)
{
this->assign(__l.begin(), __l.size());
return *this;
}
#endif // C++11
#if __cplusplus >= 201703L
/**
* @brief Set value to string constructed from a string_view.
* @param __svt An object convertible to string_view.
*/
template<typename _Tp>
_GLIBCXX20_CONSTEXPR
_If_sv<_Tp, basic_string&>
operator=(const _Tp& __svt)
{ return this->assign(__svt); }
/**
* @brief Convert to a string_view.
* @return A string_view.
*/
_GLIBCXX20_CONSTEXPR
operator __sv_type() const noexcept
{ return __sv_type(data(), size()); }
#endif // C++17
// Iterators:
/**
* Returns a read/write iterator that points to the first character in
* the %string.
*/
_GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
iterator
begin() _GLIBCXX_NOEXCEPT
{ return iterator(_M_data()); }
/**
* Returns a read-only (constant) iterator that points to the first
* character in the %string.
*/
_GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
const_iterator
begin() const _GLIBCXX_NOEXCEPT
{ return const_iterator(_M_data()); }
/**
* Returns a read/write iterator that points one past the last
* character in the %string.
*/
_GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
iterator
end() _GLIBCXX_NOEXCEPT
{ return iterator(_M_data() + this->size()); }
/**
* Returns a read-only (constant) iterator that points one past the
* last character in the %string.
*/
_GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
const_iterator
end() const _GLIBCXX_NOEXCEPT
{ return const_iterator(_M_data() + this->size()); }
/**
* Returns a read/write reverse iterator that points to the last
* character in the %string. Iteration is done in reverse element
* order.
*/
_GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
reverse_iterator
rbegin() _GLIBCXX_NOEXCEPT
{ return reverse_iterator(this->end()); }
/**