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// Components for manipulating sequences of characters -- C++ -- // Copyright (C) 1997-2018 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/atomicity.h> #include <ext/alloc_traits.h> #include <debug/debug.h> #if __cplusplus >= 201103L #include <initializer_list> #endif #if __cplusplus > 201402L # include <string_view> #endif namespace std _GLIBCXX_VISIBILITY(default) { _GLIBCXX_BEGIN_NAMESPACE_VERSION #if __cplusplus >= 201703L // Support P0426R1 changes to char_traits in C++17. # define __cpp_lib_constexpr_string 201611L #endif #if _GLIBCXX_USE_CXX11_ABI _GLIBCXX_BEGIN_NAMESPACE_CXX11 /* * @class basic_string basic_string.h <string> * @brief Managing sequences of characters and character-like objects. * * @ingroup strings * @ingroup sequences * * @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 { typedef typename __gnu_cxx::__alloc_traits<_Alloc>::template rebind<_CharT>::other _Char_alloc_type; 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); private: // type used for positions in insert, erase etc. #if __cplusplus < 201103L typedef iterator __const_iterator; #else typedef const_iterator __const_iterator; #endif #if __cplusplus > 201402L // 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. 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 { explicit __sv_wrapper(__sv_type __sv) noexcept : _M_sv(__sv) { } __sv_type _M_sv; }; #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 _Alloc_hider(pointer __dat, const _Alloc& __a) : allocator_type(__a), _M_p(__dat) { } _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; }; void _M_data(pointer __p) { _M_dataplus._M_p = __p; } void _M_length(size_type __length) { _M_string_length = __length; } pointer _M_data() const { return _M_dataplus._M_p; } pointer _M_local_data() { #if __cplusplus >= 201103L return std::pointer_traits<pointer>::pointer_to(_M_local_buf); #else return pointer(_M_local_buf); #endif } 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 } void _M_capacity(size_type __capacity) { _M_allocated_capacity = __capacity; } void _M_set_length(size_type __n) { _M_length(__n); traits_type::assign(_M_data()[__n], _CharT()); } bool _M_is_local() const { return _M_data() == _M_local_data(); } // Create & Destroy pointer _M_create(size_type&, size_type); void _M_dispose() { if (!_M_is_local()) _M_destroy(_M_allocated_capacity); } void _M_destroy(size_type __size) throw() { _Alloc_traits::deallocate(_M_get_allocator(), _M_data(), __size + 1); } // _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); } template<typename _InIterator> void _M_construct(_InIterator __beg, _InIterator __end) { typedef typename std::__is_integer<_InIterator>::__type _Integral; _M_construct_aux(__beg, __end, _Integral()); } // For Input Iterators, used in istreambuf_iterators, etc. template<typename _InIterator> 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> void _M_construct(_FwdIterator __beg, _FwdIterator __end, std::forward_iterator_tag); void _M_construct(size_type __req, _CharT __c); allocator_type& _M_get_allocator() { return _M_dataplus; } const allocator_type& _M_get_allocator() const { return _M_dataplus; } 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 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; } 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. 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. 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); } 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); } 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> 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. } static void _S_copy_chars(_CharT* __p, iterator __k1, iterator __k2) _GLIBCXX_NOEXCEPT { _S_copy_chars(__p, __k1.base(), __k2.base()); } static void _S_copy_chars(_CharT* __p, const_iterator __k1, const_iterator __k2) _GLIBCXX_NOEXCEPT { _S_copy_chars(__p, __k1.base(), __k2.base()); } static void _S_copy_chars(_CharT* __p, _CharT* __k1, _CharT* __k2) _GLIBCXX_NOEXCEPT { _S_copy(__p, __k1, __k2 - __k1); } static void _S_copy_chars(_CharT* __p, const _CharT* __k1, const _CharT* __k2) _GLIBCXX_NOEXCEPT { _S_copy(__p, __k1, __k2 - __k1); } 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); } void _M_assign(const basic_string&); void _M_mutate(size_type __pos, size_type __len1, const _CharT* __s, size_type __len2); 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. / basic_string() _GLIBCXX_NOEXCEPT_IF(is_nothrow_default_constructible<_Alloc>::value) : _M_dataplus(_M_local_data()) { _M_set_length(0); } /* * @brief Construct an empty string using allocator @a a. / explicit basic_string(const _Alloc& __a) _GLIBCXX_NOEXCEPT : _M_dataplus(_M_local_data(), __a) { _M_set_length(0); } /* * @brief Construct string with copy of value of @a __str. * @param __str Source string. / 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()); } // _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. / 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)); } /** * @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. / 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)); } /** * @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. / 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)); } /** * @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. / basic_string(const _CharT __s, size_type __n, const _Alloc& __a = _Alloc()) : _M_dataplus(_M_local_data(), __a) { _M_construct(__s, __s + __n); } /** * @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 basic_string(const _CharT __s, const _Alloc& __a = _Alloc()) : _M_dataplus(_M_local_data(), __a) { _M_construct(__s, __s ? __s + traits_type::length(__s) : __s+npos); } /** * @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 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. / basic_string(basic_string&& __str) noexcept : _M_dataplus(_M_local_data(), std::move(__str._M_get_allocator())) { if (__str._M_is_local()) { traits_type::copy(_M_local_buf, __str._M_local_buf, _S_local_capacity + 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_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). / basic_string(initializer_list<_CharT> __l, const _Alloc& __a = _Alloc()) : _M_dataplus(_M_local_data(), __a) { _M_construct(__l.begin(), __l.end()); } basic_string(const basic_string& __str, const _Alloc& __a) : _M_dataplus(_M_local_data(), __a) { _M_construct(__str.begin(), __str.end()); } 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()) { traits_type::copy(_M_local_buf, __str._M_local_buf, _S_local_capacity + 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_local_buf); __str._M_set_length(0); } else _M_construct(__str.begin(), __str.end()); } #endif // C++11 /* * @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 basic_string(_InputIterator __beg, _InputIterator __end, const _Alloc& __a = _Alloc()) : _M_dataplus(_M_local_data(), __a) { _M_construct(__beg, __end); } #if __cplusplus > 201402L /* * @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 = _If_sv<_Tp, void>> 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>> explicit basic_string(const _Tp& __t, const _Alloc& __a = _Alloc()) : basic_string(__sv_wrapper(_S_to_string_view(__t)), __a) { } /* * @brief Only internally used: Construct string from a string view * wrapper. * @param __svw string view wrapper. * @param __a Allocator to use. / explicit basic_string(__sv_wrapper __svw, const _Alloc& __a) : basic_string(__svw._M_sv.data(), __svw._M_sv.size(), __a) { } #endif // C++17 /* * @brief Destroy the string instance. / ~basic_string() { _M_dispose(); } /* * @brief Assign the value of @a str to this string. * @param __str Source string. / basic_string& operator=(const basic_string& __str) { #if __cplusplus >= 201103L if (_Alloc_traits::_S_propagate_on_copy_assign()) { if (!_Alloc_traits::_S_always_equal() && !_M_is_local() && _M_get_allocator() != __str._M_get_allocator()) { // Propagating allocator cannot free existing storage so must // deallocate it before replacing current allocator. if (__str.size() <= _S_local_capacity) { _M_destroy(_M_allocated_capacity); _M_data(_M_local_data()); _M_set_length(0); } else { const auto __len = __str.size(); auto __alloc = __str._M_get_allocator(); // If this allocation throws there are no effects: auto __ptr = _Alloc_traits::allocate(__alloc, __len + 1); _M_destroy(_M_allocated_capacity); _M_data(__ptr); _M_capacity(__len); _M_set_length(__len); } } std::__alloc_on_copy(_M_get_allocator(), __str._M_get_allocator()); } #endif return this->assign(__str); } /* * @brief Copy contents of @a s into this string. * @param __s Source null-terminated string. / 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. / 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. */ // PR 58265, this should be noexcept. // _GLIBCXX_RESOLVE_LIB_DEFECTS // 2063. Contradictory requirements for string move assignment basic_string& operator=(basic_string&& __str) noexcept(_Alloc_traits::_S_nothrow_move()) { if (!_M_is_local() && _Alloc_traits::_S_propagate_on_move_assign() && !_Alloc_traits::_S_always_equal() && _M_get_allocator() != __str._M_get_allocator()) { // 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. 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() \|\| _Alloc_traits::_S_always_equal() \|\| _M_get_allocator() == __str._M_get_allocator()) { // Just move the allocated pointer, our allocator can free it. pointer __data = nullptr; size_type __capacity; if (!_M_is_local()) { if (_Alloc_traits::_S_always_equal()) { // __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_local_buf); } 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. / basic_string& operator=(initializer_list<_CharT> __l) { this->assign(__l.begin(), __l.size()); return this; } #endif // C++11 #if __cplusplus > 201402L /** * @brief Set value to string constructed from a string_view. * @param __svt An object convertible to string_view. / template<typename _Tp> _If_sv<_Tp, basic_string&> operator=(const _Tp& __svt) { return this->assign(__svt); } /* * @brief Convert to a string_view. * @return A string_view. / 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. / iterator begin() _GLIBCXX_NOEXCEPT { return iterator(_M_data()); } /* * Returns a read-only (constant) iterator that points to the first * character in the %string. / 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. / 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. / 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. / reverse_iterator rbegin() _GLIBCXX_NOEXCEPT { return reverse_iterator(this->end()); } /* * Returns a read-only (constant) reverse iterator that points * to the last character in the %string. Iteration is done in * reverse element order. / const_reverse_iterator rbegin() const _GLIBCXX_NOEXCEPT { return const_reverse_iterator(this->end()); } /* * Returns a read/write reverse iterator that points to one before the * first character in the %string. Iteration is done in reverse * element order. / reverse_iterator rend() _GLIBCXX_NOEXCEPT { return reverse_iterator(this->begin()); } /* * Returns a read-only (constant) reverse iterator that points * to one before the first character in the %string. Iteration * is done in reverse element order. / const_reverse_iterator rend() const _GLIBCXX_NOEXCEPT { return const_reverse_iterator(this->begin()); } #if __cplusplus >= 201103L /* * Returns a read-only (constant) iterator that points to the first * character in the %string. / const_iterator cbegin() const noexcept { return const_iterator(this->_M_data()); } /* * Returns a read-only (constant) iterator that points one past the * last character in the %string. / const_iterator cend() const noexcept { return const_iterator(this->_M_data() + this->size()); } /* * Returns a read-only (constant) reverse iterator that points * to the last character in the %string. Iteration is done in * reverse element order. / const_reverse_iterator crbegin() const noexcept { return const_reverse_iterator(this->end()); } /* * Returns a read-only (constant) reverse iterator that points * to one before the first character in the %string. Iteration * is done in reverse element order. / const_reverse_iterator crend() const noexcept { return const_reverse_iterator(this->begin()); } #endif public: // Capacity: /// Returns the number of characters in the string, not including any /// null-termination. size_type size() const _GLIBCXX_NOEXCEPT { return _M_string_length; } /// Returns the number of characters in the string, not including any /// null-termination. size_type length() const _GLIBCXX_NOEXCEPT { return _M_string_length; } /// Returns the size() of the largest possible %string. size_type max_size() const _GLIBCXX_NOEXCEPT { return (_Alloc_traits::max_size(_M_get_allocator()) - 1) / 2; } /* * @brief Resizes the %string to the specified number of characters. * @param __n Number of characters the %string should contain. * @param __c Character to fill any new elements. * * This function will %resize the %string to the specified * number of characters. If the number is smaller than the * %string's current size the %string is truncated, otherwise * the %string is extended and new elements are %set to @a __c. / void resize(size_type __n, _CharT __c); /* * @brief Resizes the %string to the specified number of characters. * @param __n Number of characters the %string should contain. * * This function will resize the %string to the specified length. If * the new size is smaller than the %string's current size the %string * is truncated, otherwise the %string is extended and new characters * are default-constructed. For basic types such as char, this means * setting them to 0. / void resize(size_type __n) { this->resize(__n, _CharT()); } #if __cplusplus >= 201103L /// A non-binding request to reduce capacity() to size(). void shrink_to_fit() noexcept { #if __cpp_exceptions if (capacity() > size()) { try { reserve(0); } catch(...) { } } #endif } #endif /* * Returns the total number of characters that the %string can hold * before needing to allocate more memory. / size_type capacity() const _GLIBCXX_NOEXCEPT { return _M_is_local() ? size_type(_S_local_capacity) : _M_allocated_capacity; } /* * @brief Attempt to preallocate enough memory for specified number of * characters. * @param __res_arg Number of characters required. * @throw std::length_error If @a __res_arg exceeds @c max_size(). * * This function attempts to reserve enough memory for the * %string to hold the specified number of characters. If the * number requested is more than max_size(), length_error is * thrown. * * The advantage of this function is that if optimal code is a * necessity and the user can determine the string length that will be * required, the user can reserve the memory in %advance, and thus * prevent a possible reallocation of memory and copying of %string * data. / void reserve(size_type __res_arg = 0); /* * Erases the string, making it empty. / void clear() _GLIBCXX_NOEXCEPT { _M_set_length(0); } /* * Returns true if the %string is empty. Equivalent to * <code>this == ""</code>. / bool empty() const _GLIBCXX_NOEXCEPT { return this->size() == 0; } // Element access: /** * @brief Subscript access to the data contained in the %string. * @param __pos The index of the character to access. * @return Read-only (constant) reference to the character. * * This operator allows for easy, array-style, data access. * Note that data access with this operator is unchecked and * out_of_range lookups are not defined. (For checked lookups * see at().) / const_reference operator[] (size_type __pos) const _GLIBCXX_NOEXCEPT { __glibcxx_assert(__pos <= size()); return _M_data()[__pos]; } /* * @brief Subscript access to the data contained in the %string. * @param __pos The index of the character to access. * @return Read/write reference to the character. * * This operator allows for easy, array-style, data access. * Note that data access with this operator is unchecked and * out_of_range lookups are not defined. (For checked lookups * see at().) / reference operator[](size_type __pos) { // Allow pos == size() both in C++98 mode, as v3 extension, // and in C++11 mode. __glibcxx_assert(__pos <= size()); // In pedantic mode be strict in C++98 mode. _GLIBCXX_DEBUG_PEDASSERT(__cplusplus >= 201103L \|\| __pos < size()); return _M_data()[__pos]; } /* * @brief Provides access to the data contained in the %string. * @param __n The index of the character to access. * @return Read-only (const) reference to the character. * @throw std::out_of_range If @a n is an invalid index. * * This function provides for safer data access. The parameter is * first checked that it is in the range of the string. The function * throws out_of_range if the check fails. / const_reference at(size_type __n) const { if (__n >= this->size()) __throw_out_of_range_fmt(__N("basic_string::at: __n " "(which is %zu) >= this->size() " "(which is %zu)"), __n, this->size()); return _M_data()[__n]; } /* * @brief Provides access to the data contained in the %string. * @param __n The index of the character to access. * @return Read/write reference to the character. * @throw std::out_of_range If @a n is an invalid index. * * This function provides for safer data access. The parameter is * first checked that it is in the range of the string. The function * throws out_of_range if the check fails. / reference at(size_type __n) { if (__n >= size()) __throw_out_of_range_fmt(__N("basic_string::at: __n " "(which is %zu) >= this->size() " "(which is %zu)"), __n, this->size()); return _M_data()[__n]; } #if __cplusplus >= 201103L /* * Returns a read/write reference to the data at the first * element of the %string. / reference front() noexcept { __glibcxx_assert(!empty()); return operator[](0); } /* * Returns a read-only (constant) reference to the data at the first * element of the %string. / const_reference front() const noexcept { __glibcxx_assert(!empty()); return operator[](0); } /* * Returns a read/write reference to the data at the last * element of the %string. / reference back() noexcept { __glibcxx_assert(!empty()); return operator[](this->size() - 1); } /* * Returns a read-only (constant) reference to the data at the * last element of the %string. / const_reference back() const noexcept { __glibcxx_assert(!empty()); return operator[](this->size() - 1); } #endif // Modifiers: /* * @brief Append a string to this string. * @param __str The string to append. * @return Reference to this string. / basic_string& operator+=(const basic_string& __str) { return this->append(__str); } /* * @brief Append a C string. * @param __s The C string to append. * @return Reference to this string. / basic_string& operator+=(const _CharT __s) { return this->append(__s); } /** * @brief Append a character. * @param __c The character to append. * @return Reference to this string. / basic_string& operator+=(_CharT __c) { this->push_back(__c); return this; } #if __cplusplus >= 201103L /** * @brief Append an initializer_list of characters. * @param __l The initializer_list of characters to be appended. * @return Reference to this string. / basic_string& operator+=(initializer_list<_CharT> __l) { return this->append(__l.begin(), __l.size()); } #endif // C++11 #if __cplusplus > 201402L /* * @brief Append a string_view. * @param __svt An object convertible to string_view to be appended. * @return Reference to this string. / template<typename _Tp> _If_sv<_Tp, basic_string&> operator+=(const _Tp& __svt) { return this->append(__svt); } #endif // C++17 /* * @brief Append a string to this string. * @param __str The string to append. * @return Reference to this string. / basic_string& append(const basic_string& __str) { return _M_append(__str._M_data(), __str.size()); } /* * @brief Append a substring. * @param __str The string to append. * @param __pos Index of the first character of str to append. * @param __n The number of characters to append. * @return Reference to this string. * @throw std::out_of_range if @a __pos is not a valid index. * * This function appends @a __n characters from @a __str * starting at @a __pos to this string. If @a __n is is larger * than the number of available characters in @a __str, the * remainder of @a __str is appended. / basic_string& append(const basic_string& __str, size_type __pos, size_type __n = npos) { return _M_append(__str._M_data() + __str._M_check(__pos, "basic_string::append"), __str._M_limit(__pos, __n)); } /* * @brief Append a C substring. * @param __s The C string to append. * @param __n The number of characters to append. * @return Reference to this string. / basic_string& append(const _CharT __s, size_type __n) { __glibcxx_requires_string_len(__s, __n); _M_check_length(size_type(0), __n, "basic_string::append"); return _M_append(__s, __n); } /** * @brief Append a C string. * @param __s The C string to append. * @return Reference to this string. / basic_string& append(const _CharT __s) { __glibcxx_requires_string(__s); const size_type __n = traits_type::length(__s); _M_check_length(size_type(0), __n, "basic_string::append"); return _M_append(__s, __n); } /** * @brief Append multiple characters. * @param __n The number of characters to append. * @param __c The character to use. * @return Reference to this string. * * Appends __n copies of __c to this string. / basic_string& append(size_type __n, _CharT __c) { return _M_replace_aux(this->size(), size_type(0), __n, __c); } #if __cplusplus >= 201103L /* * @brief Append an initializer_list of characters. * @param __l The initializer_list of characters to append. * @return Reference to this string. / basic_string& append(initializer_list<_CharT> __l) { return this->append(__l.begin(), __l.size()); } #endif // C++11 /* * @brief Append a range of characters. * @param __first Iterator referencing the first character to append. * @param __last Iterator marking the end of the range. * @return Reference to this string. * * Appends characters in the range [__first,__last) to this string. / #if __cplusplus >= 201103L template<class _InputIterator, typename = std::_RequireInputIter<_InputIterator>> #else template<class _InputIterator> #endif basic_string& append(_InputIterator __first, _InputIterator __last) { return this->replace(end(), end(), __first, __last); } #if __cplusplus > 201402L /* * @brief Append a string_view. * @param __svt An object convertible to string_view to be appended. * @return Reference to this string. / template<typename _Tp> _If_sv<_Tp, basic_string&> append(const _Tp& __svt) { __sv_type __sv = __svt; return this->append(__sv.data(), __sv.size()); } /* * @brief Append a range of characters from a string_view. * @param __svt An object convertible to string_view to be appended from. * @param __pos The position in the string_view to append from. * @param __n The number of characters to append from the string_view. * @return Reference to this string. / template<typename _Tp> _If_sv<_Tp, basic_string&> append(const _Tp& __svt, size_type __pos, size_type __n = npos) { __sv_type __sv = __svt; return _M_append(__sv.data() + __sv._M_check(__pos, "basic_string::append"), __sv._M_limit(__pos, __n)); } #endif // C++17 /* * @brief Append a single character. * @param __c Character to append. / void push_back(_CharT __c) { const size_type __size = this->size(); if (__size + 1 > this->capacity()) this->_M_mutate(__size, size_type(0), 0, size_type(1)); traits_type::assign(this->_M_data()[__size], __c); this->_M_set_length(__size + 1); } /* * @brief Set value to contents of another string. * @param __str Source string to use. * @return Reference to this string. / basic_string& assign(const basic_string& __str) { this->_M_assign(__str); return this; } #if __cplusplus >= 201103L /** * @brief Set value to contents of another string. * @param __str Source string to use. * @return Reference to this string. * * This function sets this string to the exact contents of @a __str. * @a __str is a valid, but unspecified string. / basic_string& assign(basic_string&& __str) noexcept(_Alloc_traits::_S_nothrow_move()) { // _GLIBCXX_RESOLVE_LIB_DEFECTS // 2063. Contradictory requirements for string move assignment return this = std::move(__str); } #endif // C++11 /** * @brief Set value to a substring of a string. * @param __str The string to use. * @param __pos Index of the first character of str. * @param __n Number of characters to use. * @return Reference to this string. * @throw std::out_of_range if @a pos is not a valid index. * * This function sets this string to the substring of @a __str * consisting of @a __n characters at @a __pos. If @a __n is * is larger than the number of available characters in @a * __str, the remainder of @a __str is used. / basic_string& assign(const basic_string& __str, size_type __pos, size_type __n = npos) { return _M_replace(size_type(0), this->size(), __str._M_data() + __str._M_check(__pos, "basic_string::assign"), __str._M_limit(__pos, __n)); } /* * @brief Set value to a C substring. * @param __s The C string to use. * @param __n Number of characters to use. * @return Reference to this string. * * This function sets the value of this string to the first @a __n * characters of @a __s. If @a __n is is larger than the number of * available characters in @a __s, the remainder of @a __s is used. / basic_string& assign(const _CharT __s, size_type __n) { __glibcxx_requires_string_len(__s, __n); return _M_replace(size_type(0), this->size(), __s, __n); } /** * @brief Set value to contents of a C string. * @param __s The C string to use. * @return Reference to this string. * * This function sets the value of this string to the value of @a __s. * The data is copied, so there is no dependence on @a __s once the * function returns. / basic_string& assign(const _CharT __s) { __glibcxx_requires_string(__s); return _M_replace(size_type(0), this->size(), __s, traits_type::length(__s)); } /** * @brief Set value to multiple characters. * @param __n Length of the resulting string. * @param __c The character to use. * @return Reference to this string. * * This function sets the value of this string to @a __n copies of * character @a __c. / basic_string& assign(size_type __n, _CharT __c) { return _M_replace_aux(size_type(0), this->size(), __n, __c); } /* * @brief Set value to a range of characters. * @param __first Iterator referencing the first character to append. * @param __last Iterator marking the end of the range. * @return Reference to this string. * * Sets value of string to characters in the range [__first,__last). / #if __cplusplus >= 201103L template<class _InputIterator, typename = std::_RequireInputIter<_InputIterator>> #else template<class _InputIterator> #endif basic_string& assign(_InputIterator __first, _InputIterator __last) { return this->replace(begin(), end(), __first, __last); } #if __cplusplus >= 201103L /* * @brief Set value to an initializer_list of characters. * @param __l The initializer_list of characters to assign. * @return Reference to this string. / basic_string& assign(initializer_list<_CharT> __l) { return this->assign(__l.begin(), __l.size()); } #endif // C++11 #if __cplusplus > 201402L /* * @brief Set value from a string_view. * @param __svt The source object convertible to string_view. * @return Reference to this string. / template<typename _Tp> _If_sv<_Tp, basic_string&> assign(const _Tp& __svt) { __sv_type __sv = __svt; return this->assign(__sv.data(), __sv.size()); } /* * @brief Set value from a range of characters in a string_view. * @param __svt The source object convertible to string_view. * @param __pos The position in the string_view to assign from. * @param __n The number of characters to assign. * @return Reference to this string. / template<typename _Tp> _If_sv<_Tp, basic_string&> assign(const _Tp& __svt, size_type __pos, size_type __n = npos) { __sv_type __sv = __svt; return _M_replace(size_type(0), this->size(), __sv.data() + __sv._M_check(__pos, "basic_string::assign"), __sv._M_limit(__pos, __n)); } #endif // C++17 #if __cplusplus >= 201103L /* * @brief Insert multiple characters. * @param __p Const_iterator referencing location in string to * insert at. * @param __n Number of characters to insert * @param __c The character to insert. * @return Iterator referencing the first inserted char. * @throw std::length_error If new length exceeds @c max_size(). * * Inserts @a __n copies of character @a __c starting at the * position referenced by iterator @a __p. If adding * characters causes the length to exceed max_size(), * length_error is thrown. The value of the string doesn't * change if an error is thrown. / iterator insert(const_iterator __p, size_type __n, _CharT __c) { _GLIBCXX_DEBUG_PEDASSERT(__p >= begin() && __p <= end()); const size_type __pos = __p - begin(); this->replace(__p, __p, __n, __c); return iterator(this->_M_data() + __pos); } #else /* * @brief Insert multiple characters. * @param __p Iterator referencing location in string to insert at. * @param __n Number of characters to insert * @param __c The character to insert. * @throw std::length_error If new length exceeds @c max_size(). * * Inserts @a __n copies of character @a __c starting at the * position referenced by iterator @a __p. If adding * characters causes the length to exceed max_size(), * length_error is thrown. The value of the string doesn't * change if an error is thrown. / void insert(iterator __p, size_type __n, _CharT __c) { this->replace(__p, __p, __n, __c); } #endif #if __cplusplus >= 201103L /* * @brief Insert a range of characters. * @param __p Const_iterator referencing location in string to * insert at. * @param __beg Start of range. * @param __end End of range. * @return Iterator referencing the first inserted char. * @throw std::length_error If new length exceeds @c max_size(). * * Inserts characters in range [beg,end). If adding characters * causes the length to exceed max_size(), length_error is * thrown. The value of the string doesn't change if an error * is thrown. / template<class _InputIterator, typename = std::_RequireInputIter<_InputIterator>> iterator insert(const_iterator __p, _InputIterator __beg, _InputIterator __end) { _GLIBCXX_DEBUG_PEDASSERT(__p >= begin() && __p <= end()); const size_type __pos = __p - begin(); this->replace(__p, __p, __beg, __end); return iterator(this->_M_data() + __pos); } #else /* * @brief Insert a range of characters. * @param __p Iterator referencing location in string to insert at. * @param __beg Start of range. * @param __end End of range. * @throw std::length_error If new length exceeds @c max_size(). * * Inserts characters in range [__beg,__end). If adding * characters causes the length to exceed max_size(), * length_error is thrown. The value of the string doesn't * change if an error is thrown. / template<class _InputIterator> void insert(iterator __p, _InputIterator __beg, _InputIterator __end) { this->replace(__p, __p, __beg, __end); } #endif #if __cplusplus >= 201103L /* * @brief Insert an initializer_list of characters. * @param __p Iterator referencing location in string to insert at. * @param __l The initializer_list of characters to insert. * @throw std::length_error If new length exceeds @c max_size(). / void insert(iterator __p, initializer_list<_CharT> __l) { _GLIBCXX_DEBUG_PEDASSERT(__p >= begin() && __p <= end()); this->insert(__p - begin(), __l.begin(), __l.size()); } #endif // C++11 /* * @brief Insert value of a string. * @param __pos1 Iterator referencing location in string to insert at. * @param __str The string to insert. * @return Reference to this string. * @throw std::length_error If new length exceeds @c max_size(). * * Inserts value of @a __str starting at @a __pos1. If adding * characters causes the length to exceed max_size(), * length_error is thrown. The value of the string doesn't * change if an error is thrown. / basic_string& insert(size_type __pos1, const basic_string& __str) { return this->replace(__pos1, size_type(0), __str._M_data(), __str.size()); } /* * @brief Insert a substring. * @param __pos1 Iterator referencing location in string to insert at. * @param __str The string to insert. * @param __pos2 Start of characters in str to insert. * @param __n Number of characters to insert. * @return Reference to this string. * @throw std::length_error If new length exceeds @c max_size(). * @throw std::out_of_range If @a pos1 > size() or * @a __pos2 > @a str.size(). * * Starting at @a pos1, insert @a __n character of @a __str * beginning with @a __pos2. If adding characters causes the * length to exceed max_size(), length_error is thrown. If @a * __pos1 is beyond the end of this string or @a __pos2 is * beyond the end of @a __str, out_of_range is thrown. The * value of the string doesn't change if an error is thrown. / basic_string& insert(size_type __pos1, const basic_string& __str, size_type __pos2, size_type __n = npos) { return this->replace(__pos1, size_type(0), __str._M_data() + __str._M_check(__pos2, "basic_string::insert"), __str._M_limit(__pos2, __n)); } /* * @brief Insert a C substring. * @param __pos Iterator referencing location in string to insert at. * @param __s The C string to insert. * @param __n The number of characters to insert. * @return Reference to this string. * @throw std::length_error If new length exceeds @c max_size(). * @throw std::out_of_range If @a __pos is beyond the end of this * string. * * Inserts the first @a __n characters of @a __s starting at @a * __pos. If adding characters causes the length to exceed * max_size(), length_error is thrown. If @a __pos is beyond * end(), out_of_range is thrown. The value of the string * doesn't change if an error is thrown. / basic_string& insert(size_type __pos, const _CharT __s, size_type __n) { return this->replace(__pos, size_type(0), __s, __n); } /** * @brief Insert a C string. * @param __pos Iterator referencing location in string to insert at. * @param __s The C string to insert. * @return Reference to this string. * @throw std::length_error If new length exceeds @c max_size(). * @throw std::out_of_range If @a pos is beyond the end of this * string. * * Inserts the first @a n characters of @a __s starting at @a __pos. If * adding characters causes the length to exceed max_size(), * length_error is thrown. If @a __pos is beyond end(), out_of_range is * thrown. The value of the string doesn't change if an error is * thrown. / basic_string& insert(size_type __pos, const _CharT __s) { __glibcxx_requires_string(__s); return this->replace(__pos, size_type(0), __s, traits_type::length(__s)); } /** * @brief Insert multiple characters. * @param __pos Index in string to insert at. * @param __n Number of characters to insert * @param __c The character to insert. * @return Reference to this string. * @throw std::length_error If new length exceeds @c max_size(). * @throw std::out_of_range If @a __pos is beyond the end of this * string. * * Inserts @a __n copies of character @a __c starting at index * @a __pos. If adding characters causes the length to exceed * max_size(), length_error is thrown. If @a __pos > length(), * out_of_range is thrown. The value of the string doesn't * change if an error is thrown. / basic_string& insert(size_type __pos, size_type __n, _CharT __c) { return _M_replace_aux(_M_check(__pos, "basic_string::insert"), size_type(0), __n, __c); } /* * @brief Insert one character. * @param __p Iterator referencing position in string to insert at. * @param __c The character to insert. * @return Iterator referencing newly inserted char. * @throw std::length_error If new length exceeds @c max_size(). * * Inserts character @a __c at position referenced by @a __p. * If adding character causes the length to exceed max_size(), * length_error is thrown. If @a __p is beyond end of string, * out_of_range is thrown. The value of the string doesn't * change if an error is thrown. / iterator insert(__const_iterator __p, _CharT __c) { _GLIBCXX_DEBUG_PEDASSERT(__p >= begin() && __p <= end()); const size_type __pos = __p - begin(); _M_replace_aux(__pos, size_type(0), size_type(1), __c); return iterator(_M_data() + __pos); } #if __cplusplus > 201402L /* * @brief Insert a string_view. * @param __pos Iterator referencing position in string to insert at. * @param __svt The object convertible to string_view to insert. * @return Reference to this string. / template<typename _Tp> _If_sv<_Tp, basic_string&> insert(size_type __pos, const _Tp& __svt) { __sv_type __sv = __svt; return this->insert(__pos, __sv.data(), __sv.size()); } /* * @brief Insert a string_view. * @param __pos Iterator referencing position in string to insert at. * @param __svt The object convertible to string_view to insert from. * @param __pos Iterator referencing position in string_view to insert * from. * @param __n The number of characters to insert. * @return Reference to this string. / template<typename _Tp> _If_sv<_Tp, basic_string&> insert(size_type __pos1, const _Tp& __svt, size_type __pos2, size_type __n = npos) { __sv_type __sv = __svt; return this->replace(__pos1, size_type(0), __sv.data() + __sv._M_check(__pos2, "basic_string::insert"), __sv._M_limit(__pos2, __n)); } #endif // C++17 /* * @brief Remove characters. * @param __pos Index of first character to remove (default 0). * @param __n Number of characters to remove (default remainder). * @return Reference to this string. * @throw std::out_of_range If @a pos is beyond the end of this * string. * * Removes @a __n characters from this string starting at @a * __pos. The length of the string is reduced by @a __n. If * there are < @a __n characters to remove, the remainder of * the string is truncated. If @a __p is beyond end of string, * out_of_range is thrown. The value of the string doesn't * change if an error is thrown. / basic_string& erase(size_type __pos = 0, size_type __n = npos) { _M_check(__pos, "basic_string::erase"); if (__n == npos) this->_M_set_length(__pos); else if (__n != 0) this->_M_erase(__pos, _M_limit(__pos, __n)); return this; } /** * @brief Remove one character. * @param __position Iterator referencing the character to remove. * @return iterator referencing same location after removal. * * Removes the character at @a __position from this string. The value * of the string doesn't change if an error is thrown. / iterator erase(__const_iterator __position) { _GLIBCXX_DEBUG_PEDASSERT(__position >= begin() && __position < end()); const size_type __pos = __position - begin(); this->_M_erase(__pos, size_type(1)); return iterator(_M_data() + __pos); } /* * @brief Remove a range of characters. * @param __first Iterator referencing the first character to remove. * @param __last Iterator referencing the end of the range. * @return Iterator referencing location of first after removal. * * Removes the characters in the range [first,last) from this string. * The value of the string doesn't change if an error is thrown. / iterator erase(__const_iterator __first, __const_iterator __last) { _GLIBCXX_DEBUG_PEDASSERT(__first >= begin() && __first <= __last && __last <= end()); const size_type __pos = __first - begin(); if (__last == end()) this->_M_set_length(__pos); else this->_M_erase(__pos, __last - __first); return iterator(this->_M_data() + __pos); } #if __cplusplus >= 201103L /* * @brief Remove the last character. * * The string must be non-empty. / void pop_back() noexcept { __glibcxx_assert(!empty()); _M_erase(size() - 1, 1); } #endif // C++11 /* * @brief Replace characters with value from another string. * @param __pos Index of first character to replace. * @param __n Number of characters to be replaced. * @param __str String to insert. * @return Reference to this string. * @throw std::out_of_range If @a pos is beyond the end of this * string. * @throw std::length_error If new length exceeds @c max_size(). * * Removes the characters in the range [__pos,__pos+__n) from * this string. In place, the value of @a __str is inserted. * If @a __pos is beyond end of string, out_of_range is thrown. * If the length of the result exceeds max_size(), length_error * is thrown. The value of the string doesn't change if an * error is thrown. / basic_string& replace(size_type __pos, size_type __n, const basic_string& __str) { return this->replace(__pos, __n, __str._M_data(), __str.size()); } /* * @brief Replace characters with value from another string. * @param __pos1 Index of first character to replace. * @param __n1 Number of characters to be replaced. * @param __str String to insert. * @param __pos2 Index of first character of str to use. * @param __n2 Number of characters from str to use. * @return Reference to this string. * @throw std::out_of_range If @a __pos1 > size() or @a __pos2 > * __str.size(). * @throw std::length_error If new length exceeds @c max_size(). * * Removes the characters in the range [__pos1,__pos1 + n) from this * string. In place, the value of @a __str is inserted. If @a __pos is * beyond end of string, out_of_range is thrown. If the length of the * result exceeds max_size(), length_error is thrown. The value of the * string doesn't change if an error is thrown. / basic_string& replace(size_type __pos1, size_type __n1, const basic_string& __str, size_type __pos2, size_type __n2 = npos) { return this->replace(__pos1, __n1, __str._M_data() + __str._M_check(__pos2, "basic_string::replace"), __str._M_limit(__pos2, __n2)); } /* * @brief Replace characters with value of a C substring. * @param __pos Index of first character to replace. * @param __n1 Number of characters to be replaced. * @param __s C string to insert. * @param __n2 Number of characters from @a s to use. * @return Reference to this string. * @throw std::out_of_range If @a pos1 > size(). * @throw std::length_error If new length exceeds @c max_size(). * * Removes the characters in the range [__pos,__pos + __n1) * from this string. In place, the first @a __n2 characters of * @a __s are inserted, or all of @a __s if @a __n2 is too large. If * @a __pos is beyond end of string, out_of_range is thrown. If * the length of result exceeds max_size(), length_error is * thrown. The value of the string doesn't change if an error * is thrown. / basic_string& replace(size_type __pos, size_type __n1, const _CharT __s, size_type __n2) { __glibcxx_requires_string_len(__s, __n2); return _M_replace(_M_check(__pos, "basic_string::replace"), _M_limit(__pos, __n1), __s, __n2); } /** * @brief Replace characters with value of a C string. * @param __pos Index of first character to replace. * @param __n1 Number of characters to be replaced. * @param __s C string to insert. * @return Reference to this string. * @throw std::out_of_range If @a pos > size(). * @throw std::length_error If new length exceeds @c max_size(). * * Removes the characters in the range [__pos,__pos + __n1) * from this string. In place, the characters of @a __s are * inserted. If @a __pos is beyond end of string, out_of_range * is thrown. If the length of result exceeds max_size(), * length_error is thrown. The value of the string doesn't * change if an error is thrown. / basic_string& replace(size_type __pos, size_type __n1, const _CharT __s) { __glibcxx_requires_string(__s); return this->replace(__pos, __n1, __s, traits_type::length(__s)); } /** * @brief Replace characters with multiple characters. * @param __pos Index of first character to replace. * @param __n1 Number of characters to be replaced. * @param __n2 Number of characters to insert. * @param __c Character to insert. * @return Reference to this string. * @throw std::out_of_range If @a __pos > size(). * @throw std::length_error If new length exceeds @c max_size(). * * Removes the characters in the range [pos,pos + n1) from this * string. In place, @a __n2 copies of @a __c are inserted. * If @a __pos is beyond end of string, out_of_range is thrown. * If the length of result exceeds max_size(), length_error is * thrown. The value of the string doesn't change if an error * is thrown. / basic_string& replace(size_type __pos, size_type __n1, size_type __n2, _CharT __c) { return _M_replace_aux(_M_check(__pos, "basic_string::replace"), _M_limit(__pos, __n1), __n2, __c); } /* * @brief Replace range of characters with string. * @param __i1 Iterator referencing start of range to replace. * @param __i2 Iterator referencing end of range to replace. * @param __str String value to insert. * @return Reference to this string. * @throw std::length_error If new length exceeds @c max_size(). * * Removes the characters in the range [__i1,__i2). In place, * the value of @a __str is inserted. If the length of result * exceeds max_size(), length_error is thrown. The value of * the string doesn't change if an error is thrown. / basic_string& replace(__const_iterator __i1, __const_iterator __i2, const basic_string& __str) { return this->replace(__i1, __i2, __str._M_data(), __str.size()); } /* * @brief Replace range of characters with C substring. * @param __i1 Iterator referencing start of range to replace. * @param __i2 Iterator referencing end of range to replace. * @param __s C string value to insert. * @param __n Number of characters from s to insert. * @return Reference to this string. * @throw std::length_error If new length exceeds @c max_size(). * * Removes the characters in the range [__i1,__i2). In place, * the first @a __n characters of @a __s are inserted. If the * length of result exceeds max_size(), length_error is thrown. * The value of the string doesn't change if an error is * thrown. / basic_string& replace(__const_iterator __i1, __const_iterator __i2, const _CharT __s, size_type __n) { _GLIBCXX_DEBUG_PEDASSERT(begin() <= __i1 && __i1 <= __i2 && __i2 <= end()); return this->replace(__i1 - begin(), __i2 - __i1, __s, __n); } /** * @brief Replace range of characters with C string. * @param __i1 Iterator referencing start of range to replace. * @param __i2 Iterator referencing end of range to replace. * @param __s C string value to insert. * @return Reference to this string. * @throw std::length_error If new length exceeds @c max_size(). * * Removes the characters in the range [__i1,__i2). In place, * the characters of @a __s are inserted. If the length of * result exceeds max_size(), length_error is thrown. The * value of the string doesn't change if an error is thrown. / basic_string& replace(__const_iterator __i1, __const_iterator __i2, const _CharT __s) { __glibcxx_requires_string(__s); return this->replace(__i1, __i2, __s, traits_type::length(__s)); } /** * @brief Replace range of characters with multiple characters * @param __i1 Iterator referencing start of range to replace. * @param __i2 Iterator referencing end of range to replace. * @param __n Number of characters to insert. * @param __c Character to insert. * @return Reference to this string. * @throw std::length_error If new length exceeds @c max_size(). * * Removes the characters in the range [__i1,__i2). In place, * @a __n copies of @a __c are inserted. If the length of * result exceeds max_size(), length_error is thrown. The * value of the string doesn't change if an error is thrown. / basic_string& replace(__const_iterator __i1, __const_iterator __i2, size_type __n, _CharT __c) { _GLIBCXX_DEBUG_PEDASSERT(begin() <= __i1 && __i1 <= __i2 && __i2 <= end()); return _M_replace_aux(__i1 - begin(), __i2 - __i1, __n, __c); } /* * @brief Replace range of characters with range. * @param __i1 Iterator referencing start of range to replace. * @param __i2 Iterator referencing end of range to replace. * @param __k1 Iterator referencing start of range to insert. * @param __k2 Iterator referencing end of range to insert. * @return Reference to this string. * @throw std::length_error If new length exceeds @c max_size(). * * Removes the characters in the range [__i1,__i2). In place, * characters in the range [__k1,__k2) are inserted. If the * length of result exceeds max_size(), length_error is thrown. * The value of the string doesn't change if an error is * thrown. / #if __cplusplus >= 201103L template<class _InputIterator, typename = std::_RequireInputIter<_InputIterator>> basic_string& replace(const_iterator __i1, const_iterator __i2, _InputIterator __k1, _InputIterator __k2) { _GLIBCXX_DEBUG_PEDASSERT(begin() <= __i1 && __i1 <= __i2 && __i2 <= end()); __glibcxx_requires_valid_range(__k1, __k2); return this->_M_replace_dispatch(__i1, __i2, __k1, __k2, std::__false_type()); } #else template<class _InputIterator> #ifdef _GLIBCXX_DISAMBIGUATE_REPLACE_INST typename __enable_if_not_native_iterator<_InputIterator>::__type #else basic_string& #endif replace(iterator __i1, iterator __i2, _InputIterator __k1, _InputIterator __k2) { _GLIBCXX_DEBUG_PEDASSERT(begin() <= __i1 && __i1 <= __i2 && __i2 <= end()); __glibcxx_requires_valid_range(__k1, __k2); typedef typename std::__is_integer<_InputIterator>::__type _Integral; return _M_replace_dispatch(__i1, __i2, __k1, __k2, _Integral()); } #endif // Specializations for the common case of pointer and iterator: // useful to avoid the overhead of temporary buffering in _M_replace. basic_string& replace(__const_iterator __i1, __const_iterator __i2, _CharT __k1, _CharT* __k2) { _GLIBCXX_DEBUG_PEDASSERT(begin() <= __i1 && __i1 <= __i2 && __i2 <= end()); __glibcxx_requires_valid_range(__k1, __k2); return this->replace(__i1 - begin(), __i2 - __i1, __k1, __k2 - __k1); } basic_string& replace(__const_iterator __i1, __const_iterator __i2, const _CharT* __k1, const _CharT* __k2) { _GLIBCXX_DEBUG_PEDASSERT(begin() <= __i1 && __i1 <= __i2 && __i2 <= end()); __glibcxx_requires_valid_range(__k1, __k2); return this->replace(__i1 - begin(), __i2 - __i1, __k1, __k2 - __k1); } basic_string& replace(__const_iterator __i1, __const_iterator __i2, iterator __k1, iterator __k2) { _GLIBCXX_DEBUG_PEDASSERT(begin() <= __i1 && __i1 <= __i2 && __i2 <= end()); __glibcxx_requires_valid_range(__k1, __k2); return this->replace(__i1 - begin(), __i2 - __i1, __k1.base(), __k2 - __k1); } basic_string& replace(__const_iterator __i1, __const_iterator __i2, const_iterator __k1, const_iterator __k2) { _GLIBCXX_DEBUG_PEDASSERT(begin() <= __i1 && __i1 <= __i2 && __i2 <= end()); __glibcxx_requires_valid_range(__k1, __k2); return this->replace(__i1 - begin(), __i2 - __i1, __k1.base(), __k2 - __k1); } #if __cplusplus >= 201103L /** * @brief Replace range of characters with initializer_list. * @param __i1 Iterator referencing start of range to replace. * @param __i2 Iterator referencing end of range to replace. * @param __l The initializer_list of characters to insert. * @return Reference to this string. * @throw std::length_error If new length exceeds @c max_size(). * * Removes the characters in the range [__i1,__i2). In place, * characters in the range [__k1,__k2) are inserted. If the * length of result exceeds max_size(), length_error is thrown. * The value of the string doesn't change if an error is * thrown. / basic_string& replace(const_iterator __i1, const_iterator __i2, initializer_list<_CharT> __l) { return this->replace(__i1, __i2, __l.begin(), __l.size()); } #endif // C++11 #if __cplusplus > 201402L /* * @brief Replace range of characters with string_view. * @param __pos The position to replace at. * @param __n The number of characters to replace. * @param __svt The object convertible to string_view to insert. * @return Reference to this string. / template<typename _Tp> _If_sv<_Tp, basic_string&> replace(size_type __pos, size_type __n, const _Tp& __svt) { __sv_type __sv = __svt; return this->replace(__pos, __n, __sv.data(), __sv.size()); } /* * @brief Replace range of characters with string_view. * @param __pos1 The position to replace at. * @param __n1 The number of characters to replace. * @param __svt The object convertible to string_view to insert from. * @param __pos2 The position in the string_view to insert from. * @param __n2 The number of characters to insert. * @return Reference to this string. / template<typename _Tp> _If_sv<_Tp, basic_string&> replace(size_type __pos1, size_type __n1, const _Tp& __svt, size_type __pos2, size_type __n2 = npos) { __sv_type __sv = __svt; return this->replace(__pos1, __n1, __sv.data() + __sv._M_check(__pos2, "basic_string::replace"), __sv._M_limit(__pos2, __n2)); } /* * @brief Replace range of characters with string_view. * @param __i1 An iterator referencing the start position to replace at. * @param __i2 An iterator referencing the end position for the replace. * @param __svt The object convertible to string_view to insert from. * @return Reference to this string. / template<typename _Tp> _If_sv<_Tp, basic_string&> replace(const_iterator __i1, const_iterator __i2, const _Tp& __svt) { __sv_type __sv = __svt; return this->replace(__i1 - begin(), __i2 - __i1, __sv); } #endif // C++17 private: template<class _Integer> basic_string& _M_replace_dispatch(const_iterator __i1, const_iterator __i2, _Integer __n, _Integer __val, __true_type) { return _M_replace_aux(__i1 - begin(), __i2 - __i1, __n, __val); } template<class _InputIterator> basic_string& _M_replace_dispatch(const_iterator __i1, const_iterator __i2, _InputIterator __k1, _InputIterator __k2, __false_type); basic_string& _M_replace_aux(size_type __pos1, size_type __n1, size_type __n2, _CharT __c); basic_string& _M_replace(size_type __pos, size_type __len1, const _CharT __s, const size_type __len2); basic_string& _M_append(const _CharT* __s, size_type __n); public: /** * @brief Copy substring into C string. * @param __s C string to copy value into. * @param __n Number of characters to copy. * @param __pos Index of first character to copy. * @return Number of characters actually copied * @throw std::out_of_range If __pos > size(). * * Copies up to @a __n characters starting at @a __pos into the * C string @a __s. If @a __pos is %greater than size(), * out_of_range is thrown. / size_type copy(_CharT __s, size_type __n, size_type __pos = 0) const; /** * @brief Swap contents with another string. * @param __s String to swap with. * * Exchanges the contents of this string with that of @a __s in constant * time. / void swap(basic_string& __s) _GLIBCXX_NOEXCEPT; // String operations: /* * @brief Return const pointer to null-terminated contents. * * This is a handle to internal data. Do not modify or dire things may * happen. / const _CharT c_str() const _GLIBCXX_NOEXCEPT { return _M_data(); } /** * @brief Return const pointer to contents. * * This is a pointer to internal data. It is undefined to modify * the contents through the returned pointer. To get a pointer that * allows modifying the contents use @c &str[0] instead, * (or in C++17 the non-const @c str.data() overload). / const _CharT data() const _GLIBCXX_NOEXCEPT { return _M_data(); } #if __cplusplus > 201402L /** * @brief Return non-const pointer to contents. * * This is a pointer to the character sequence held by the string. * Modifying the characters in the sequence is allowed. / _CharT data() noexcept { return _M_data(); } #endif /** * @brief Return copy of allocator used to construct this string. / allocator_type get_allocator() const _GLIBCXX_NOEXCEPT { return _M_get_allocator(); } /* * @brief Find position of a C substring. * @param __s C string to locate. * @param __pos Index of character to search from. * @param __n Number of characters from @a s to search for. * @return Index of start of first occurrence. * * Starting from @a __pos, searches forward for the first @a * __n characters in @a __s within this string. If found, * returns the index where it begins. If not found, returns * npos. / size_type find(const _CharT __s, size_type __pos, size_type __n) const _GLIBCXX_NOEXCEPT; /** * @brief Find position of a string. * @param __str String to locate. * @param __pos Index of character to search from (default 0). * @return Index of start of first occurrence. * * Starting from @a __pos, searches forward for value of @a __str within * this string. If found, returns the index where it begins. If not * found, returns npos. / size_type find(const basic_string& __str, size_type __pos = 0) const _GLIBCXX_NOEXCEPT { return this->find(__str.data(), __pos, __str.size()); } #if __cplusplus > 201402L /* * @brief Find position of a string_view. * @param __svt The object convertible to string_view to locate. * @param __pos Index of character to search from (default 0). * @return Index of start of first occurrence. / template<typename _Tp> _If_sv<_Tp, size_type> find(const _Tp& __svt, size_type __pos = 0) const noexcept(is_same<_Tp, __sv_type>::value) { __sv_type __sv = __svt; return this->find(__sv.data(), __pos, __sv.size()); } #endif // C++17 /* * @brief Find position of a C string. * @param __s C string to locate. * @param __pos Index of character to search from (default 0). * @return Index of start of first occurrence. * * Starting from @a __pos, searches forward for the value of @a * __s within this string. If found, returns the index where * it begins. If not found, returns npos. / size_type find(const _CharT __s, size_type __pos = 0) const _GLIBCXX_NOEXCEPT { __glibcxx_requires_string(__s); return this->find(__s, __pos, traits_type::length(__s)); } /** * @brief Find position of a character. * @param __c Character to locate. * @param __pos Index of character to search from (default 0). * @return Index of first occurrence. * * Starting from @a __pos, searches forward for @a __c within * this string. If found, returns the index where it was * found. If not found, returns npos. / size_type find(_CharT __c, size_type __pos = 0) const _GLIBCXX_NOEXCEPT; /* * @brief Find last position of a string. * @param __str String to locate. * @param __pos Index of character to search back from (default end). * @return Index of start of last occurrence. * * Starting from @a __pos, searches backward for value of @a * __str within this string. If found, returns the index where * it begins. If not found, returns npos. / size_type rfind(const basic_string& __str, size_type __pos = npos) const _GLIBCXX_NOEXCEPT { return this->rfind(__str.data(), __pos, __str.size()); } #if __cplusplus > 201402L /* * @brief Find last position of a string_view. * @param __svt The object convertible to string_view to locate. * @param __pos Index of character to search back from (default end). * @return Index of start of last occurrence. / template<typename _Tp> _If_sv<_Tp, size_type> rfind(const _Tp& __svt, size_type __pos = npos) const noexcept(is_same<_Tp, __sv_type>::value) { __sv_type __sv = __svt; return this->rfind(__sv.data(), __pos, __sv.size()); } #endif // C++17 /* * @brief Find last position of a C substring. * @param __s C string to locate. * @param __pos Index of character to search back from. * @param __n Number of characters from s to search for. * @return Index of start of last occurrence. * * Starting from @a __pos, searches backward for the first @a * __n characters in @a __s within this string. If found, * returns the index where it begins. If not found, returns * npos. / size_type rfind(const _CharT __s, size_type __pos, size_type __n) const _GLIBCXX_NOEXCEPT; /** * @brief Find last position of a C string. * @param __s C string to locate. * @param __pos Index of character to start search at (default end). * @return Index of start of last occurrence. * * Starting from @a __pos, searches backward for the value of * @a __s within this string. If found, returns the index * where it begins. If not found, returns npos. / size_type rfind(const _CharT __s, size_type __pos = npos) const { __glibcxx_requires_string(__s); return this->rfind(__s, __pos, traits_type::length(__s)); } /** * @brief Find last position of a character. * @param __c Character to locate. * @param __pos Index of character to search back from (default end). * @return Index of last occurrence. * * Starting from @a __pos, searches backward for @a __c within * this string. If found, returns the index where it was * found. If not found, returns npos. / size_type rfind(_CharT __c, size_type __pos = npos) const _GLIBCXX_NOEXCEPT; /* * @brief Find position of a character of string. * @param __str String containing characters to locate. * @param __pos Index of character to search from (default 0). * @return Index of first occurrence. * * Starting from @a __pos, searches forward for one of the * characters of @a __str within this string. If found, * returns the index where it was found. If not found, returns * npos. / size_type find_first_of(const basic_string& __str, size_type __pos = 0) const _GLIBCXX_NOEXCEPT { return this->find_first_of(__str.data(), __pos, __str.size()); } #if __cplusplus > 201402L /* * @brief Find position of a character of a string_view. * @param __svt An object convertible to string_view containing * characters to locate. * @param __pos Index of character to search from (default 0). * @return Index of first occurrence. / template<typename _Tp> _If_sv<_Tp, size_type> find_first_of(const _Tp& __svt, size_type __pos = 0) const noexcept(is_same<_Tp, __sv_type>::value) { __sv_type __sv = __svt; return this->find_first_of(__sv.data(), __pos, __sv.size()); } #endif // C++17 /* * @brief Find position of a character of C substring. * @param __s String containing characters to locate. * @param __pos Index of character to search from. * @param __n Number of characters from s to search for. * @return Index of first occurrence. * * Starting from @a __pos, searches forward for one of the * first @a __n characters of @a __s within this string. If * found, returns the index where it was found. If not found, * returns npos. / size_type find_first_of(const _CharT __s, size_type __pos, size_type __n) const _GLIBCXX_NOEXCEPT; /** * @brief Find position of a character of C string. * @param __s String containing characters to locate. * @param __pos Index of character to search from (default 0). * @return Index of first occurrence. * * Starting from @a __pos, searches forward for one of the * characters of @a __s within this string. If found, returns * the index where it was found. If not found, returns npos. / size_type find_first_of(const _CharT __s, size_type __pos = 0) const _GLIBCXX_NOEXCEPT { __glibcxx_requires_string(__s); return this->find_first_of(__s, __pos, traits_type::length(__s)); } /** * @brief Find position of a character. * @param __c Character to locate. * @param __pos Index of character to search from (default 0). * @return Index of first occurrence. * * Starting from @a __pos, searches forward for the character * @a __c within this string. If found, returns the index * where it was found. If not found, returns npos. * * Note: equivalent to find(__c, __pos). / size_type find_first_of(_CharT __c, size_type __pos = 0) const _GLIBCXX_NOEXCEPT { return this->find(__c, __pos); } /* * @brief Find last position of a character of string. * @param __str String containing characters to locate. * @param __pos Index of character to search back from (default end). * @return Index of last occurrence. * * Starting from @a __pos, searches backward for one of the * characters of @a __str within this string. If found, * returns the index where it was found. If not found, returns * npos. / size_type find_last_of(const basic_string& __str, size_type __pos = npos) const _GLIBCXX_NOEXCEPT { return this->find_last_of(__str.data(), __pos, __str.size()); } #if __cplusplus > 201402L /* * @brief Find last position of a character of string. * @param __svt An object convertible to string_view containing * characters to locate. * @param __pos Index of character to search back from (default end). * @return Index of last occurrence. / template<typename _Tp> _If_sv<_Tp, size_type> find_last_of(const _Tp& __svt, size_type __pos = npos) const noexcept(is_same<_Tp, __sv_type>::value) { __sv_type __sv = __svt; return this->find_last_of(__sv.data(), __pos, __sv.size()); } #endif // C++17 /* * @brief Find last position of a character of C substring. * @param __s C string containing characters to locate. * @param __pos Index of character to search back from. * @param __n Number of characters from s to search for. * @return Index of last occurrence. * * Starting from @a __pos, searches backward for one of the * first @a __n characters of @a __s within this string. If * found, returns the index where it was found. If not found, * returns npos. / size_type find_last_of(const _CharT __s, size_type __pos, size_type __n) const _GLIBCXX_NOEXCEPT; /** * @brief Find last position of a character of C string. * @param __s C string containing characters to locate. * @param __pos Index of character to search back from (default end). * @return Index of last occurrence. * * Starting from @a __pos, searches backward for one of the * characters of @a __s within this string. If found, returns * the index where it was found. If not found, returns npos. / size_type find_last_of(const _CharT __s, size_type __pos = npos) const _GLIBCXX_NOEXCEPT { __glibcxx_requires_string(__s); return this->find_last_of(__s, __pos, traits_type::length(__s)); } /** * @brief Find last position of a character. * @param __c Character to locate. * @param __pos Index of character to search back from (default end). * @return Index of last occurrence. * * Starting from @a __pos, searches backward for @a __c within * this string. If found, returns the index where it was * found. If not found, returns npos. * * Note: equivalent to rfind(__c, __pos). / size_type find_last_of(_CharT __c, size_type __pos = npos) const _GLIBCXX_NOEXCEPT { return this->rfind(__c, __pos); } /* * @brief Find position of a character not in string. * @param __str String containing characters to avoid. * @param __pos Index of character to search from (default 0). * @return Index of first occurrence. * * Starting from @a __pos, searches forward for a character not contained * in @a __str within this string. If found, returns the index where it * was found. If not found, returns npos. / size_type find_first_not_of(const basic_string& __str, size_type __pos = 0) const _GLIBCXX_NOEXCEPT { return this->find_first_not_of(__str.data(), __pos, __str.size()); } #if __cplusplus > 201402L /* * @brief Find position of a character not in a string_view. * @param __svt A object convertible to string_view containing * characters to avoid. * @param __pos Index of character to search from (default 0). * @return Index of first occurrence. / template<typename _Tp> _If_sv<_Tp, size_type> find_first_not_of(const _Tp& __svt, size_type __pos = 0) const noexcept(is_same<_Tp, __sv_type>::value) { __sv_type __sv = __svt; return this->find_first_not_of(__sv.data(), __pos, __sv.size()); } #endif // C++17 /* * @brief Find position of a character not in C substring. * @param __s C string containing characters to avoid. * @param __pos Index of character to search from. * @param __n Number of characters from __s to consider. * @return Index of first occurrence. * * Starting from @a __pos, searches forward for a character not * contained in the first @a __n characters of @a __s within * this string. If found, returns the index where it was * found. If not found, returns npos. / size_type find_first_not_of(const _CharT __s, size_type __pos, size_type __n) const _GLIBCXX_NOEXCEPT; /** * @brief Find position of a character not in C string. * @param __s C string containing characters to avoid. * @param __pos Index of character to search from (default 0). * @return Index of first occurrence. * * Starting from @a __pos, searches forward for a character not * contained in @a __s within this string. If found, returns * the index where it was found. If not found, returns npos. / size_type find_first_not_of(const _CharT __s, size_type __pos = 0) const _GLIBCXX_NOEXCEPT { __glibcxx_requires_string(__s); return this->find_first_not_of(__s, __pos, traits_type::length(__s)); } /** * @brief Find position of a different character. * @param __c Character to avoid. * @param __pos Index of character to search from (default 0). * @return Index of first occurrence. * * Starting from @a __pos, searches forward for a character * other than @a __c within this string. If found, returns the * index where it was found. If not found, returns npos. / size_type find_first_not_of(_CharT __c, size_type __pos = 0) const _GLIBCXX_NOEXCEPT; /* * @brief Find last position of a character not in string. * @param __str String containing characters to avoid. * @param __pos Index of character to search back from (default end). * @return Index of last occurrence. * * Starting from @a __pos, searches backward for a character * not contained in @a __str within this string. If found, * returns the index where it was found. If not found, returns * npos. / size_type find_last_not_of(const basic_string& __str, size_type __pos = npos) const _GLIBCXX_NOEXCEPT { return this->find_last_not_of(__str.data(), __pos, __str.size()); } #if __cplusplus > 201402L /* * @brief Find last position of a character not in a string_view. * @param __svt An object convertible to string_view containing * characters to avoid. * @param __pos Index of character to search back from (default end). * @return Index of last occurrence. / template<typename _Tp> _If_sv<_Tp, size_type> find_last_not_of(const _Tp& __svt, size_type __pos = npos) const noexcept(is_same<_Tp, __sv_type>::value) { __sv_type __sv = __svt; return this->find_last_not_of(__sv.data(), __pos, __sv.size()); } #endif // C++17 /* * @brief Find last position of a character not in C substring. * @param __s C string containing characters to avoid. * @param __pos Index of character to search back from. * @param __n Number of characters from s to consider. * @return Index of last occurrence. * * Starting from @a __pos, searches backward for a character not * contained in the first @a __n characters of @a __s within this string. * If found, returns the index where it was found. If not found, * returns npos. / size_type find_last_not_of(const _CharT __s, size_type __pos, size_type __n) const _GLIBCXX_NOEXCEPT; /** * @brief Find last position of a character not in C string. * @param __s C string containing characters to avoid. * @param __pos Index of character to search back from (default end). * @return Index of last occurrence. * * Starting from @a __pos, searches backward for a character * not contained in @a __s within this string. If found, * returns the index where it was found. If not found, returns * npos. / size_type find_last_not_of(const _CharT __s, size_type __pos = npos) const _GLIBCXX_NOEXCEPT { __glibcxx_requires_string(__s); return this->find_last_not_of(__s, __pos, traits_type::length(__s)); } /** * @brief Find last position of a different character. * @param __c Character to avoid. * @param __pos Index of character to search back from (default end). * @return Index of last occurrence. * * Starting from @a __pos, searches backward for a character other than * @a __c within this string. If found, returns the index where it was * found. If not found, returns npos. / size_type find_last_not_of(_CharT __c, size_type __pos = npos) const _GLIBCXX_NOEXCEPT; /* * @brief Get a substring. * @param __pos Index of first character (default 0). * @param __n Number of characters in substring (default remainder). * @return The new string. * @throw std::out_of_range If __pos > size(). * * Construct and return a new string using the @a __n * characters starting at @a __pos. If the string is too * short, use the remainder of the characters. If @a __pos is * beyond the end of the string, out_of_range is thrown. / basic_string substr(size_type __pos = 0, size_type __n = npos) const { return basic_string(this, _M_check(__pos, "basic_string::substr"), __n); } /** * @brief Compare to a string. * @param __str String to compare against. * @return Integer < 0, 0, or > 0. * * Returns an integer < 0 if this string is ordered before @a * __str, 0 if their values are equivalent, or > 0 if this * string is ordered after @a __str. Determines the effective * length rlen of the strings to compare as the smallest of * size() and str.size(). The function then compares the two * strings by calling traits::compare(data(), str.data(),rlen). * If the result of the comparison is nonzero returns it, * otherwise the shorter one is ordered first. / int compare(const basic_string& __str) const { const size_type __size = this->size(); const size_type __osize = __str.size(); const size_type __len = std::min(__size, __osize); int __r = traits_type::compare(_M_data(), __str.data(), __len); if (!__r) __r = _S_compare(__size, __osize); return __r; } #if __cplusplus > 201402L /* * @brief Compare to a string_view. * @param __svt An object convertible to string_view to compare against. * @return Integer < 0, 0, or > 0. / template<typename _Tp> _If_sv<_Tp, int> compare(const _Tp& __svt) const noexcept(is_same<_Tp, __sv_type>::value) { __sv_type __sv = __svt; const size_type __size = this->size(); const size_type __osize = __sv.size(); const size_type __len = std::min(__size, __osize); int __r = traits_type::compare(_M_data(), __sv.data(), __len); if (!__r) __r = _S_compare(__size, __osize); return __r; } /* * @brief Compare to a string_view. * @param __pos A position in the string to start comparing from. * @param __n The number of characters to compare. * @param __svt An object convertible to string_view to compare * against. * @return Integer < 0, 0, or > 0. / template<typename _Tp> _If_sv<_Tp, int> compare(size_type __pos, size_type __n, const _Tp& __svt) const noexcept(is_same<_Tp, __sv_type>::value) { __sv_type __sv = __svt; return __sv_type(this).substr(__pos, __n).compare(__sv); } /** * @brief Compare to a string_view. * @param __pos1 A position in the string to start comparing from. * @param __n1 The number of characters to compare. * @param __svt An object convertible to string_view to compare * against. * @param __pos2 A position in the string_view to start comparing from. * @param __n2 The number of characters to compare. * @return Integer < 0, 0, or > 0. / template<typename _Tp> _If_sv<_Tp, int> compare(size_type __pos1, size_type __n1, const _Tp& __svt, size_type __pos2, size_type __n2 = npos) const noexcept(is_same<_Tp, __sv_type>::value) { __sv_type __sv = __svt; return __sv_type(this) .substr(__pos1, __n1).compare(__sv.substr(__pos2, __n2)); } #endif // C++17 /** * @brief Compare substring to a string. * @param __pos Index of first character of substring. * @param __n Number of characters in substring. * @param __str String to compare against. * @return Integer < 0, 0, or > 0. * * Form the substring of this string from the @a __n characters * starting at @a __pos. Returns an integer < 0 if the * substring is ordered before @a __str, 0 if their values are * equivalent, or > 0 if the substring is ordered after @a * __str. Determines the effective length rlen of the strings * to compare as the smallest of the length of the substring * and @a __str.size(). The function then compares the two * strings by calling * traits::compare(substring.data(),str.data(),rlen). If the * result of the comparison is nonzero returns it, otherwise * the shorter one is ordered first. / int compare(size_type __pos, size_type __n, const basic_string& __str) const; /* * @brief Compare substring to a substring. * @param __pos1 Index of first character of substring. * @param __n1 Number of characters in substring. * @param __str String to compare against. * @param __pos2 Index of first character of substring of str. * @param __n2 Number of characters in substring of str. * @return Integer < 0, 0, or > 0. * * Form the substring of this string from the @a __n1 * characters starting at @a __pos1. Form the substring of @a * __str from the @a __n2 characters starting at @a __pos2. * Returns an integer < 0 if this substring is ordered before * the substring of @a __str, 0 if their values are equivalent, * or > 0 if this substring is ordered after the substring of * @a __str. Determines the effective length rlen of the * strings to compare as the smallest of the lengths of the * substrings. The function then compares the two strings by * calling * traits::compare(substring.data(),str.substr(pos2,n2).data(),rlen). * If the result of the comparison is nonzero returns it, * otherwise the shorter one is ordered first. / int compare(size_type __pos1, size_type __n1, const basic_string& __str, size_type __pos2, size_type __n2 = npos) const; /* * @brief Compare to a C string. * @param __s C string to compare against. * @return Integer < 0, 0, or > 0. * * Returns an integer < 0 if this string is ordered before @a __s, 0 if * their values are equivalent, or > 0 if this string is ordered after * @a __s. Determines the effective length rlen of the strings to * compare as the smallest of size() and the length of a string * constructed from @a __s. The function then compares the two strings * by calling traits::compare(data(),s,rlen). If the result of the * comparison is nonzero returns it, otherwise the shorter one is * ordered first. / int compare(const _CharT __s) const _GLIBCXX_NOEXCEPT; // _GLIBCXX_RESOLVE_LIB_DEFECTS // 5 String::compare specification questionable /** * @brief Compare substring to a C string. * @param __pos Index of first character of substring. * @param __n1 Number of characters in substring. * @param __s C string to compare against. * @return Integer < 0, 0, or > 0. * * Form the substring of this string from the @a __n1 * characters starting at @a pos. Returns an integer < 0 if * the substring is ordered before @a __s, 0 if their values * are equivalent, or > 0 if the substring is ordered after @a * __s. Determines the effective length rlen of the strings to * compare as the smallest of the length of the substring and * the length of a string constructed from @a __s. The * function then compares the two string by calling * traits::compare(substring.data(),__s,rlen). If the result of * the comparison is nonzero returns it, otherwise the shorter * one is ordered first. / int compare(size_type __pos, size_type __n1, const _CharT __s) const; /** * @brief Compare substring against a character %array. * @param __pos Index of first character of substring. * @param __n1 Number of characters in substring. * @param __s character %array to compare against. * @param __n2 Number of characters of s. * @return Integer < 0, 0, or > 0. * * Form the substring of this string from the @a __n1 * characters starting at @a __pos. Form a string from the * first @a __n2 characters of @a __s. Returns an integer < 0 * if this substring is ordered before the string from @a __s, * 0 if their values are equivalent, or > 0 if this substring * is ordered after the string from @a __s. Determines the * effective length rlen of the strings to compare as the * smallest of the length of the substring and @a __n2. The * function then compares the two strings by calling * traits::compare(substring.data(),s,rlen). If the result of * the comparison is nonzero returns it, otherwise the shorter * one is ordered first. * * NB: s must have at least n2 characters, '\\0' has * no special meaning. / int compare(size_type __pos, size_type __n1, const _CharT __s, size_type __n2) const; // Allow basic_stringbuf::__xfer_bufptrs to call _M_length: template<typename, typename, typename> friend class basic_stringbuf; }; _GLIBCXX_END_NAMESPACE_CXX11 #else // !_GLIBCXX_USE_CXX11_ABI // Reference-counted COW string implentation /** * @class basic_string basic_string.h <string> * @brief Managing sequences of characters and character-like objects. * * @ingroup strings * @ingroup sequences * * @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. * * @doctodo * * * Documentation? What's that? * Nathan Myers <ncm@cantrip.org>. * * A string looks like this: * * @code * [_Rep] * _M_length * [basic_string<char_type>] _M_capacity * _M_dataplus _M_refcount * _M_p ----------------> unnamed array of char_type * @endcode * * Where the _M_p points to the first character in the string, and * you cast it to a pointer-to-_Rep and subtract 1 to get a * pointer to the header. * * This approach has the enormous advantage that a string object * requires only one allocation. All the ugliness is confined * within a single %pair of inline functions, which each compile to * a single @a add instruction: _Rep::_M_data(), and * string::_M_rep(); and the allocation function which gets a * block of raw bytes and with room enough and constructs a _Rep * object at the front. * * The reason you want _M_data pointing to the character %array and * not the _Rep is so that the debugger can see the string * contents. (Probably we should add a non-inline member to get * the _Rep for the debugger to use, so users can check the actual * string length.) * * Note that the _Rep object is a POD so that you can have a * static <em>empty string</em> _Rep object already @a constructed before * static constructors have run. The reference-count encoding is * chosen so that a 0 indicates one reference, so you never try to * destroy the empty-string _Rep object. * * All but the last paragraph is considered pretty conventional * for a C++ string implementation. / // 21.3 Template class basic_string template<typename _CharT, typename _Traits, typename _Alloc> class basic_string { typedef typename _Alloc::template rebind<_CharT>::other _CharT_alloc_type; // Types: public: typedef _Traits traits_type; typedef typename _Traits::char_type value_type; typedef _Alloc allocator_type; typedef typename _CharT_alloc_type::size_type size_type; typedef typename _CharT_alloc_type::difference_type difference_type; typedef typename _CharT_alloc_type::reference reference; typedef typename _CharT_alloc_type::const_reference const_reference; typedef typename _CharT_alloc_type::pointer pointer; typedef typename _CharT_alloc_type::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; private: // _Rep: string representation // Invariants: // 1. String really contains _M_length + 1 characters: due to 21.3.4 // must be kept null-terminated. // 2. _M_capacity >= _M_length // Allocated memory is always (_M_capacity + 1) sizeof(_CharT). // 3. _M_refcount has three states: // -1: leaked, one reference, no ref-copies allowed, non-const. // 0: one reference, non-const. // n>0: n + 1 references, operations require a lock, const. // 4. All fields==0 is an empty string, given the extra storage // beyond-the-end for a null terminator; thus, the shared // empty string representation needs no constructor. struct _Rep_base { size_type _M_length; size_type _M_capacity; _Atomic_word _M_refcount; }; struct _Rep : _Rep_base { // Types: typedef typename _Alloc::template rebind<char>::other _Raw_bytes_alloc; // (Public) Data members: // The maximum number of individual char_type elements of an // individual string is determined by _S_max_size. This is the // value that will be returned by max_size(). (Whereas npos // is the maximum number of bytes the allocator can allocate.) // If one was to divvy up the theoretical largest size string, // with a terminating character and m _CharT elements, it'd // look like this: // npos = sizeof(_Rep) + (m * sizeof(_CharT)) + sizeof(_CharT) // Solving for m: // m = ((npos - sizeof(_Rep))/sizeof(CharT)) - 1 // In addition, this implementation quarters this amount. static const size_type _S_max_size; static const _CharT _S_terminal; // The following storage is init'd to 0 by the linker, resulting // (carefully) in an empty string with one reference. static size_type _S_empty_rep_storage[]; static _Rep& _S_empty_rep() _GLIBCXX_NOEXCEPT { // NB: Mild hack to avoid strict-aliasing warnings. Note that // _S_empty_rep_storage is never modified and the punning should // be reasonably safe in this case. void* __p = reinterpret_cast<void>(&_S_empty_rep_storage); return reinterpret_cast<_Rep>(__p); } bool _M_is_leaked() const _GLIBCXX_NOEXCEPT { #if defined(__GTHREADS) // _M_refcount is mutated concurrently by _M_refcopy/_M_dispose, // so we need to use an atomic load. However, _M_is_leaked // predicate does not change concurrently (i.e. the string is either // leaked or not), so a relaxed load is enough. return __atomic_load_n(&this->_M_refcount, __ATOMIC_RELAXED) < 0; #else return this->_M_refcount < 0; #endif } bool _M_is_shared() const _GLIBCXX_NOEXCEPT { #if defined(__GTHREADS) // _M_refcount is mutated concurrently by _M_refcopy/_M_dispose, // so we need to use an atomic load. Another thread can drop last // but one reference concurrently with this check, so we need this // load to be acquire to synchronize with release fetch_and_add in // _M_dispose. return __atomic_load_n(&this->_M_refcount, __ATOMIC_ACQUIRE) > 0; #else return this->_M_refcount > 0; #endif } void _M_set_leaked() _GLIBCXX_NOEXCEPT { this->_M_refcount = -1; } void _M_set_sharable() _GLIBCXX_NOEXCEPT { this->_M_refcount = 0; } void _M_set_length_and_sharable(size_type __n) _GLIBCXX_NOEXCEPT { #if _GLIBCXX_FULLY_DYNAMIC_STRING == 0 if (__builtin_expect(this != &_S_empty_rep(), false)) #endif { this->_M_set_sharable(); // One reference. this->_M_length = __n; traits_type::assign(this->_M_refdata()[__n], _S_terminal); // grrr. (per 21.3.4) // You cannot leave those LWG people alone for a second. } } _CharT _M_refdata() throw() { return reinterpret_cast<_CharT>(this + 1); } _CharT _M_grab(const _Alloc& __alloc1, const _Alloc& __alloc2) { return (!_M_is_leaked() && __alloc1 == __alloc2) ? _M_refcopy() : _M_clone(__alloc1); } // Create & Destroy static _Rep* _S_create(size_type, size_type, const _Alloc&); void _M_dispose(const _Alloc& __a) _GLIBCXX_NOEXCEPT { #if _GLIBCXX_FULLY_DYNAMIC_STRING == 0 if (__builtin_expect(this != &_S_empty_rep(), false)) #endif { // Be race-detector-friendly. For more info see bits/c++config. _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&this->_M_refcount); // Decrement of _M_refcount is acq_rel, because: // - all but last decrements need to release to synchronize with // the last decrement that will delete the object. // - the last decrement needs to acquire to synchronize with // all the previous decrements. // - last but one decrement needs to release to synchronize with // the acquire load in _M_is_shared that will conclude that // the object is not shared anymore. if (__gnu_cxx::__exchange_and_add_dispatch(&this->_M_refcount, -1) <= 0) { _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&this->_M_refcount); _M_destroy(__a); } } } // XXX MT void _M_destroy(const _Alloc&) throw(); _CharT* _M_refcopy() throw() { #if _GLIBCXX_FULLY_DYNAMIC_STRING == 0 if (__builtin_expect(this != &_S_empty_rep(), false)) #endif __gnu_cxx::__atomic_add_dispatch(&this->_M_refcount, 1); return _M_refdata(); } // XXX MT _CharT* _M_clone(const _Alloc&, size_type __res = 0); }; // Use empty-base optimization: http://www.cantrip.org/emptyopt.html struct _Alloc_hider : _Alloc { _Alloc_hider(_CharT* __dat, const _Alloc& __a) _GLIBCXX_NOEXCEPT : _Alloc(__a), _M_p(__dat) { } _CharT* _M_p; // The actual data. }; public: // Data Members (public): // NB: This is an unsigned type, and thus represents the maximum // size that the allocator can hold. /// Value returned by various member functions when they fail. static const size_type npos = static_cast<size_type>(-1); private: // Data Members (private): mutable _Alloc_hider _M_dataplus; _CharT* _M_data() const _GLIBCXX_NOEXCEPT { return _M_dataplus._M_p; } _CharT* _M_data(_CharT* __p) _GLIBCXX_NOEXCEPT { return (_M_dataplus._M_p = __p); } _Rep* _M_rep() const _GLIBCXX_NOEXCEPT { return &((reinterpret_cast<_Rep> (_M_data()))[-1]); } // For the internal use we have functions similar to `begin'/`end' // but they do not call _M_leak. iterator _M_ibegin() const _GLIBCXX_NOEXCEPT { return iterator(_M_data()); } iterator _M_iend() const _GLIBCXX_NOEXCEPT { return iterator(_M_data() + this->size()); } void _M_leak() // for use in begin() & non-const op[] { if (!_M_rep()->_M_is_leaked()) _M_leak_hard(); } 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; } 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. 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. static void _M_copy(_CharT* __d, const _CharT* __s, size_type __n) _GLIBCXX_NOEXCEPT { if (__n == 1) traits_type::assign(__d, __s); else traits_type::copy(__d, __s, __n); } static void _M_move(_CharT* __d, const _CharT* __s, size_type __n) _GLIBCXX_NOEXCEPT { if (__n == 1) traits_type::assign(__d, __s); else traits_type::move(__d, __s, __n); } static void _M_assign(_CharT* __d, size_type __n, _CharT __c) _GLIBCXX_NOEXCEPT { 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> 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. } static void _S_copy_chars(_CharT* __p, iterator __k1, iterator __k2) _GLIBCXX_NOEXCEPT { _S_copy_chars(__p, __k1.base(), __k2.base()); } static void _S_copy_chars(_CharT* __p, const_iterator __k1, const_iterator __k2) _GLIBCXX_NOEXCEPT { _S_copy_chars(__p, __k1.base(), __k2.base()); } static void _S_copy_chars(_CharT* __p, _CharT* __k1, _CharT* __k2) _GLIBCXX_NOEXCEPT { _M_copy(__p, __k1, __k2 - __k1); } static void _S_copy_chars(_CharT* __p, const _CharT* __k1, const _CharT* __k2) _GLIBCXX_NOEXCEPT { _M_copy(__p, __k1, __k2 - __k1); } 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); } void _M_mutate(size_type __pos, size_type __len1, size_type __len2); void _M_leak_hard(); static _Rep& _S_empty_rep() _GLIBCXX_NOEXCEPT { return _Rep::_S_empty_rep(); } #if __cplusplus > 201402L // 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. 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 { explicit __sv_wrapper(__sv_type __sv) noexcept : _M_sv(__sv) { } __sv_type _M_sv; }; #endif 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. / basic_string() #if _GLIBCXX_FULLY_DYNAMIC_STRING == 0 : _M_dataplus(_S_empty_rep()._M_refdata(), _Alloc()) { } #else : _M_dataplus(_S_construct(size_type(), _CharT(), _Alloc()), _Alloc()){ } #endif /* * @brief Construct an empty string using allocator @a a. / explicit basic_string(const _Alloc& __a); // NB: per LWG issue 42, semantics different from IS: /* * @brief Construct string with copy of value of @a str. * @param __str Source string. / basic_string(const basic_string& __str); // _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. / basic_string(const basic_string& __str, size_type __pos, const _Alloc& __a = _Alloc()); /* * @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. / basic_string(const basic_string& __str, size_type __pos, size_type __n); /* * @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. / basic_string(const basic_string& __str, size_type __pos, size_type __n, const _Alloc& __a); /* * @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. / basic_string(const _CharT __s, size_type __n, const _Alloc& __a = _Alloc()); /** * @brief Construct string as copy of a C string. * @param __s Source C string. * @param __a Allocator to use (default is default allocator). / basic_string(const _CharT __s, const _Alloc& __a = _Alloc()); /** * @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). / basic_string(size_type __n, _CharT __c, const _Alloc& __a = _Alloc()); #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. / basic_string(basic_string&& __str) #if _GLIBCXX_FULLY_DYNAMIC_STRING == 0 noexcept // FIXME C++11: should always be noexcept. #endif : _M_dataplus(__str._M_dataplus) { #if _GLIBCXX_FULLY_DYNAMIC_STRING == 0 __str._M_data(_S_empty_rep()._M_refdata()); #else __str._M_data(_S_construct(size_type(), _CharT(), get_allocator())); #endif } / * @brief Construct string from an initializer %list. * @param __l std::initializer_list of characters. * @param __a Allocator to use (default is default allocator). / basic_string(initializer_list<_CharT> __l, const _Alloc& __a = _Alloc()); #endif // C++11 /* * @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). / template<class _InputIterator> basic_string(_InputIterator __beg, _InputIterator __end, const _Alloc& __a = _Alloc()); #if __cplusplus > 201402L /* * @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 = _If_sv<_Tp, void>> 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>> explicit basic_string(const _Tp& __t, const _Alloc& __a = _Alloc()) : basic_string(__sv_wrapper(_S_to_string_view(__t)), __a) { } /* * @brief Only internally used: Construct string from a string view * wrapper. * @param __svw string view wrapper. * @param __a Allocator to use. / explicit basic_string(__sv_wrapper __svw, const _Alloc& __a) : basic_string(__svw._M_sv.data(), __svw._M_sv.size(), __a) { } #endif // C++17 /* * @brief Destroy the string instance. / ~basic_string() _GLIBCXX_NOEXCEPT { _M_rep()->_M_dispose(this->get_allocator()); } /* * @brief Assign the value of @a str to this string. * @param __str Source string. / 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. / 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. / 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. */ // PR 58265, this should be noexcept. basic_string& operator=(basic_string&& __str) { // NB: DR 1204. this->swap(__str); return this; } /** * @brief Set value to string constructed from initializer %list. * @param __l std::initializer_list. / basic_string& operator=(initializer_list<_CharT> __l) { this->assign(__l.begin(), __l.size()); return this; } #endif // C++11 #if __cplusplus > 201402L /** * @brief Set value to string constructed from a string_view. * @param __svt An object convertible to string_view. / template<typename _Tp> _If_sv<_Tp, basic_string&> operator=(const _Tp& __svt) { return this->assign(__svt); } /* * @brief Convert to a string_view. * @return A string_view. / 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. Unshares the string. / iterator begin() // FIXME C++11: should be noexcept. { _M_leak(); return iterator(_M_data()); } /* * Returns a read-only (constant) iterator that points to the first * character in the %string. / 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. Unshares the string. / iterator end() // FIXME C++11: should be noexcept. { _M_leak(); return iterator(_M_data() + this->size()); } /* * Returns a read-only (constant) iterator that points one past the * last character in the %string. / 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. Unshares the string. / reverse_iterator rbegin() // FIXME C++11: should be noexcept. { return reverse_iterator(this->end()); } /* * Returns a read-only (constant) reverse iterator that points * to the last character in the %string. Iteration is done in * reverse element order. / const_reverse_iterator rbegin() const _GLIBCXX_NOEXCEPT { return const_reverse_iterator(this->end()); } /* * Returns a read/write reverse iterator that points to one before the * first character in the %string. Iteration is done in reverse * element order. Unshares the string. / reverse_iterator rend() // FIXME C++11: should be noexcept. { return reverse_iterator(this->begin()); } /* * Returns a read-only (constant) reverse iterator that points * to one before the first character in the %string. Iteration * is done in reverse element order. / const_reverse_iterator rend() const _GLIBCXX_NOEXCEPT { return const_reverse_iterator(this->begin()); } #if __cplusplus >= 201103L /* * Returns a read-only (constant) iterator that points to the first * character in the %string. / const_iterator cbegin() const noexcept { return const_iterator(this->_M_data()); } /* * Returns a read-only (constant) iterator that points one past the * last character in the %string. / const_iterator cend() const noexcept { return const_iterator(this->_M_data() + this->size()); } /* * Returns a read-only (constant) reverse iterator that points * to the last character in the %string. Iteration is done in * reverse element order. / const_reverse_iterator crbegin() const noexcept { return const_reverse_iterator(this->end()); } /* * Returns a read-only (constant) reverse iterator that points * to one before the first character in the %string. Iteration * is done in reverse element order. / const_reverse_iterator crend() const noexcept { return const_reverse_iterator(this->begin()); } #endif public: // Capacity: /// Returns the number of characters in the string, not including any /// null-termination. size_type size() const _GLIBCXX_NOEXCEPT { return _M_rep()->_M_length; } /// Returns the number of characters in the string, not including any /// null-termination. size_type length() const _GLIBCXX_NOEXCEPT { return _M_rep()->_M_length; } /// Returns the size() of the largest possible %string. size_type max_size() const _GLIBCXX_NOEXCEPT { return _Rep::_S_max_size; } /* * @brief Resizes the %string to the specified number of characters. * @param __n Number of characters the %string should contain. * @param __c Character to fill any new elements. * * This function will %resize the %string to the specified * number of characters. If the number is smaller than the * %string's current size the %string is truncated, otherwise * the %string is extended and new elements are %set to @a __c. / void resize(size_type __n, _CharT __c); /* * @brief Resizes the %string to the specified number of characters. * @param __n Number of characters the %string should contain. * * This function will resize the %string to the specified length. If * the new size is smaller than the %string's current size the %string * is truncated, otherwise the %string is extended and new characters * are default-constructed. For basic types such as char, this means * setting them to 0. / void resize(size_type __n) { this->resize(__n, _CharT()); } #if __cplusplus >= 201103L /// A non-binding request to reduce capacity() to size(). void shrink_to_fit() _GLIBCXX_NOEXCEPT { #if __cpp_exceptions if (capacity() > size()) { try { reserve(0); } catch(...) { } } #endif } #endif /* * Returns the total number of characters that the %string can hold * before needing to allocate more memory. / size_type capacity() const _GLIBCXX_NOEXCEPT { return _M_rep()->_M_capacity; } /* * @brief Attempt to preallocate enough memory for specified number of * characters. * @param __res_arg Number of characters required. * @throw std::length_error If @a __res_arg exceeds @c max_size(). * * This function attempts to reserve enough memory for the * %string to hold the specified number of characters. If the * number requested is more than max_size(), length_error is * thrown. * * The advantage of this function is that if optimal code is a * necessity and the user can determine the string length that will be * required, the user can reserve the memory in %advance, and thus * prevent a possible reallocation of memory and copying of %string * data. / void reserve(size_type __res_arg = 0); /* * Erases the string, making it empty. / #if _GLIBCXX_FULLY_DYNAMIC_STRING == 0 void clear() _GLIBCXX_NOEXCEPT { if (_M_rep()->_M_is_shared()) { _M_rep()->_M_dispose(this->get_allocator()); _M_data(_S_empty_rep()._M_refdata()); } else _M_rep()->_M_set_length_and_sharable(0); } #else // PR 56166: this should not throw. void clear() { _M_mutate(0, this->size(), 0); } #endif /* * Returns true if the %string is empty. Equivalent to * <code>this == ""</code>. / bool empty() const _GLIBCXX_NOEXCEPT { return this->size() == 0; } // Element access: /** * @brief Subscript access to the data contained in the %string. * @param __pos The index of the character to access. * @return Read-only (constant) reference to the character. * * This operator allows for easy, array-style, data access. * Note that data access with this operator is unchecked and * out_of_range lookups are not defined. (For checked lookups * see at().) / const_reference operator[] (size_type __pos) const _GLIBCXX_NOEXCEPT { __glibcxx_assert(__pos <= size()); return _M_data()[__pos]; } /* * @brief Subscript access to the data contained in the %string. * @param __pos The index of the character to access. * @return Read/write reference to the character. * * This operator allows for easy, array-style, data access. * Note that data access with this operator is unchecked and * out_of_range lookups are not defined. (For checked lookups * see at().) Unshares the string. / reference operator[](size_type __pos) { // Allow pos == size() both in C++98 mode, as v3 extension, // and in C++11 mode. __glibcxx_assert(__pos <= size()); // In pedantic mode be strict in C++98 mode. _GLIBCXX_DEBUG_PEDASSERT(__cplusplus >= 201103L \|\| __pos < size()); _M_leak(); return _M_data()[__pos]; } /* * @brief Provides access to the data contained in the %string. * @param __n The index of the character to access. * @return Read-only (const) reference to the character. * @throw std::out_of_range If @a n is an invalid index. * * This function provides for safer data access. The parameter is * first checked that it is in the range of the string. The function * throws out_of_range if the check fails. / const_reference at(size_type __n) const { if (__n >= this->size()) __throw_out_of_range_fmt(__N("basic_string::at: __n " "(which is %zu) >= this->size() " "(which is %zu)"), __n, this->size()); return _M_data()[__n]; } /* * @brief Provides access to the data contained in the %string. * @param __n The index of the character to access. * @return Read/write reference to the character. * @throw std::out_of_range If @a n is an invalid index. * * This function provides for safer data access. The parameter is * first checked that it is in the range of the string. The function * throws out_of_range if the check fails. Success results in * unsharing the string. / reference at(size_type __n) { if (__n >= size()) __throw_out_of_range_fmt(__N("basic_string::at: __n " "(which is %zu) >= this->size() " "(which is %zu)"), __n, this->size()); _M_leak(); return _M_data()[__n]; } #if __cplusplus >= 201103L /* * Returns a read/write reference to the data at the first * element of the %string. / reference front() { __glibcxx_assert(!empty()); return operator[](0); } /* * Returns a read-only (constant) reference to the data at the first * element of the %string. / const_reference front() const noexcept { __glibcxx_assert(!empty()); return operator[](0); } /* * Returns a read/write reference to the data at the last * element of the %string. / reference back() { __glibcxx_assert(!empty()); return operator[](this->size() - 1); } /* * Returns a read-only (constant) reference to the data at the * last element of the %string. / const_reference back() const noexcept { __glibcxx_assert(!empty()); return operator[](this->size() - 1); } #endif // Modifiers: /* * @brief Append a string to this string. * @param __str The string to append. * @return Reference to this string. / basic_string& operator+=(const basic_string& __str) { return this->append(__str); } /* * @brief Append a C string. * @param __s The C string to append. * @return Reference to this string. / basic_string& operator+=(const _CharT __s) { return this->append(__s); } /** * @brief Append a character. * @param __c The character to append. * @return Reference to this string. / basic_string& operator+=(_CharT __c) { this->push_back(__c); return this; } #if __cplusplus >= 201103L /** * @brief Append an initializer_list of characters. * @param __l The initializer_list of characters to be appended. * @return Reference to this string. / basic_string& operator+=(initializer_list<_CharT> __l) { return this->append(__l.begin(), __l.size()); } #endif // C++11 #if __cplusplus > 201402L /* * @brief Append a string_view. * @param __svt The object convertible to string_view to be appended. * @return Reference to this string. / template<typename _Tp> _If_sv<_Tp, basic_string&> operator+=(const _Tp& __svt) { return this->append(__svt); } #endif // C++17 /* * @brief Append a string to this string. * @param __str The string to append. * @return Reference to this string. / basic_string& append(const basic_string& __str); /* * @brief Append a substring. * @param __str The string to append. * @param __pos Index of the first character of str to append. * @param __n The number of characters to append. * @return Reference to this string. * @throw std::out_of_range if @a __pos is not a valid index. * * This function appends @a __n characters from @a __str * starting at @a __pos to this string. If @a __n is is larger * than the number of available characters in @a __str, the * remainder of @a __str is appended. / basic_string& append(const basic_string& __str, size_type __pos, size_type __n = npos); /* * @brief Append a C substring. * @param __s The C string to append. * @param __n The number of characters to append. * @return Reference to this string. / basic_string& append(const _CharT __s, size_type __n); /** * @brief Append a C string. * @param __s The C string to append. * @return Reference to this string. / basic_string& append(const _CharT __s) { __glibcxx_requires_string(__s); return this->append(__s, traits_type::length(__s)); } /** * @brief Append multiple characters. * @param __n The number of characters to append. * @param __c The character to use. * @return Reference to this string. * * Appends __n copies of __c to this string. / basic_string& append(size_type __n, _CharT __c); #if __cplusplus >= 201103L /* * @brief Append an initializer_list of characters. * @param __l The initializer_list of characters to append. * @return Reference to this string. / basic_string& append(initializer_list<_CharT> __l) { return this->append(__l.begin(), __l.size()); } #endif // C++11 /* * @brief Append a range of characters. * @param __first Iterator referencing the first character to append. * @param __last Iterator marking the end of the range. * @return Reference to this string. * * Appends characters in the range [__first,__last) to this string. / template<class _InputIterator> basic_string& append(_InputIterator __first, _InputIterator __last) { return this->replace(_M_iend(), _M_iend(), __first, __last); } #if __cplusplus > 201402L /* * @brief Append a string_view. * @param __svt The object convertible to string_view to be appended. * @return Reference to this string. / template<typename _Tp> _If_sv<_Tp, basic_string&> append(const _Tp& __svt) { __sv_type __sv = __svt; return this->append(__sv.data(), __sv.size()); } /* * @brief Append a range of characters from a string_view. * @param __svt The object convertible to string_view to be appended * from. * @param __pos The position in the string_view to append from. * @param __n The number of characters to append from the string_view. * @return Reference to this string. / template<typename _Tp> _If_sv<_Tp, basic_string&> append(const _Tp& __svt, size_type __pos, size_type __n = npos) { __sv_type __sv = __svt; return append(__sv.data() + __sv._M_check(__pos, "basic_string::append"), __sv._M_limit(__pos, __n)); } #endif // C++17 /* * @brief Append a single character. * @param __c Character to append. / void push_back(_CharT __c) { const size_type __len = 1 + this->size(); if (__len > this->capacity() \|\| _M_rep()->_M_is_shared()) this->reserve(__len); traits_type::assign(_M_data()[this->size()], __c); _M_rep()->_M_set_length_and_sharable(__len); } /* * @brief Set value to contents of another string. * @param __str Source string to use. * @return Reference to this string. / basic_string& assign(const basic_string& __str); #if __cplusplus >= 201103L /* * @brief Set value to contents of another string. * @param __str Source string to use. * @return Reference to this string. * * This function sets this string to the exact contents of @a __str. * @a __str is a valid, but unspecified string. / // PR 58265, this should be noexcept. basic_string& assign(basic_string&& __str) { this->swap(__str); return this; } #endif // C++11 /** * @brief Set value to a substring of a string. * @param __str The string to use. * @param __pos Index of the first character of str. * @param __n Number of characters to use. * @return Reference to this string. * @throw std::out_of_range if @a pos is not a valid index. * * This function sets this string to the substring of @a __str * consisting of @a __n characters at @a __pos. If @a __n is * is larger than the number of available characters in @a * __str, the remainder of @a __str is used. / basic_string& assign(const basic_string& __str, size_type __pos, size_type __n = npos) { return this->assign(__str._M_data() + __str._M_check(__pos, "basic_string::assign"), __str._M_limit(__pos, __n)); } /* * @brief Set value to a C substring. * @param __s The C string to use. * @param __n Number of characters to use. * @return Reference to this string. * * This function sets the value of this string to the first @a __n * characters of @a __s. If @a __n is is larger than the number of * available characters in @a __s, the remainder of @a __s is used. / basic_string& assign(const _CharT __s, size_type __n); /** * @brief Set value to contents of a C string. * @param __s The C string to use. * @return Reference to this string. * * This function sets the value of this string to the value of @a __s. * The data is copied, so there is no dependence on @a __s once the * function returns. / basic_string& assign(const _CharT __s) { __glibcxx_requires_string(__s); return this->assign(__s, traits_type::length(__s)); } /** * @brief Set value to multiple characters. * @param __n Length of the resulting string. * @param __c The character to use. * @return Reference to this string. * * This function sets the value of this string to @a __n copies of * character @a __c. / basic_string& assign(size_type __n, _CharT __c) { return _M_replace_aux(size_type(0), this->size(), __n, __c); } /* * @brief Set value to a range of characters. * @param __first Iterator referencing the first character to append. * @param __last Iterator marking the end of the range. * @return Reference to this string. * * Sets value of string to characters in the range [__first,__last). / template<class _InputIterator> basic_string& assign(_InputIterator __first, _InputIterator __last) { return this->replace(_M_ibegin(), _M_iend(), __first, __last); } #if __cplusplus >= 201103L /* * @brief Set value to an initializer_list of characters. * @param __l The initializer_list of characters to assign. * @return Reference to this string. / basic_string& assign(initializer_list<_CharT> __l) { return this->assign(__l.begin(), __l.size()); } #endif // C++11 #if __cplusplus > 201402L /* * @brief Set value from a string_view. * @param __svt The source object convertible to string_view. * @return Reference to this string. / template<typename _Tp> _If_sv<_Tp, basic_string&> assign(const _Tp& __svt) { __sv_type __sv = __svt; return this->assign(__sv.data(), __sv.size()); } /* * @brief Set value from a range of characters in a string_view. * @param __svt The source object convertible to string_view. * @param __pos The position in the string_view to assign from. * @param __n The number of characters to assign. * @return Reference to this string. / template<typename _Tp> _If_sv<_Tp, basic_string&> assign(const _Tp& __svt, size_type __pos, size_type __n = npos) { __sv_type __sv = __svt; return assign(__sv.data() + __sv._M_check(__pos, "basic_string::assign"), __sv._M_limit(__pos, __n)); } #endif // C++17 /* * @brief Insert multiple characters. * @param __p Iterator referencing location in string to insert at. * @param __n Number of characters to insert * @param __c The character to insert. * @throw std::length_error If new length exceeds @c max_size(). * * Inserts @a __n copies of character @a __c starting at the * position referenced by iterator @a __p. If adding * characters causes the length to exceed max_size(), * length_error is thrown. The value of the string doesn't * change if an error is thrown. / void insert(iterator __p, size_type __n, _CharT __c) { this->replace(__p, __p, __n, __c); } /* * @brief Insert a range of characters. * @param __p Iterator referencing location in string to insert at. * @param __beg Start of range. * @param __end End of range. * @throw std::length_error If new length exceeds @c max_size(). * * Inserts characters in range [__beg,__end). If adding * characters causes the length to exceed max_size(), * length_error is thrown. The value of the string doesn't * change if an error is thrown. / template<class _InputIterator> void insert(iterator __p, _InputIterator __beg, _InputIterator __end) { this->replace(__p, __p, __beg, __end); } #if __cplusplus >= 201103L /* * @brief Insert an initializer_list of characters. * @param __p Iterator referencing location in string to insert at. * @param __l The initializer_list of characters to insert. * @throw std::length_error If new length exceeds @c max_size(). / void insert(iterator __p, initializer_list<_CharT> __l) { _GLIBCXX_DEBUG_PEDASSERT(__p >= _M_ibegin() && __p <= _M_iend()); this->insert(__p - _M_ibegin(), __l.begin(), __l.size()); } #endif // C++11 /* * @brief Insert value of a string. * @param __pos1 Iterator referencing location in string to insert at. * @param __str The string to insert. * @return Reference to this string. * @throw std::length_error If new length exceeds @c max_size(). * * Inserts value of @a __str starting at @a __pos1. If adding * characters causes the length to exceed max_size(), * length_error is thrown. The value of the string doesn't * change if an error is thrown. / basic_string& insert(size_type __pos1, const basic_string& __str) { return this->insert(__pos1, __str, size_type(0), __str.size()); } /* * @brief Insert a substring. * @param __pos1 Iterator referencing location in string to insert at. * @param __str The string to insert. * @param __pos2 Start of characters in str to insert. * @param __n Number of characters to insert. * @return Reference to this string. * @throw std::length_error If new length exceeds @c max_size(). * @throw std::out_of_range If @a pos1 > size() or * @a __pos2 > @a str.size(). * * Starting at @a pos1, insert @a __n character of @a __str * beginning with @a __pos2. If adding characters causes the * length to exceed max_size(), length_error is thrown. If @a * __pos1 is beyond the end of this string or @a __pos2 is * beyond the end of @a __str, out_of_range is thrown. The * value of the string doesn't change if an error is thrown. / basic_string& insert(size_type __pos1, const basic_string& __str, size_type __pos2, size_type __n = npos) { return this->insert(__pos1, __str._M_data() + __str._M_check(__pos2, "basic_string::insert"), __str._M_limit(__pos2, __n)); } /* * @brief Insert a C substring. * @param __pos Iterator referencing location in string to insert at. * @param __s The C string to insert. * @param __n The number of characters to insert. * @return Reference to this string. * @throw std::length_error If new length exceeds @c max_size(). * @throw std::out_of_range If @a __pos is beyond the end of this * string. * * Inserts the first @a __n characters of @a __s starting at @a * __pos. If adding characters causes the length to exceed * max_size(), length_error is thrown. If @a __pos is beyond * end(), out_of_range is thrown. The value of the string * doesn't change if an error is thrown. / basic_string& insert(size_type __pos, const _CharT __s, size_type __n); /** * @brief Insert a C string. * @param __pos Iterator referencing location in string to insert at. * @param __s The C string to insert. * @return Reference to this string. * @throw std::length_error If new length exceeds @c max_size(). * @throw std::out_of_range If @a pos is beyond the end of this * string. * * Inserts the first @a n characters of @a __s starting at @a __pos. If * adding characters causes the length to exceed max_size(), * length_error is thrown. If @a __pos is beyond end(), out_of_range is * thrown. The value of the string doesn't change if an error is * thrown. / basic_string& insert(size_type __pos, const _CharT __s) { __glibcxx_requires_string(__s); return this->insert(__pos, __s, traits_type::length(__s)); } /** * @brief Insert multiple characters. * @param __pos Index in string to insert at. * @param __n Number of characters to insert * @param __c The character to insert. * @return Reference to this string. * @throw std::length_error If new length exceeds @c max_size(). * @throw std::out_of_range If @a __pos is beyond the end of this * string. * * Inserts @a __n copies of character @a __c starting at index * @a __pos. If adding characters causes the length to exceed * max_size(), length_error is thrown. If @a __pos > length(), * out_of_range is thrown. The value of the string doesn't * change if an error is thrown. / basic_string& insert(size_type __pos, size_type __n, _CharT __c) { return _M_replace_aux(_M_check(__pos, "basic_string::insert"), size_type(0), __n, __c); } /* * @brief Insert one character. * @param __p Iterator referencing position in string to insert at. * @param __c The character to insert. * @return Iterator referencing newly inserted char. * @throw std::length_error If new length exceeds @c max_size(). * * Inserts character @a __c at position referenced by @a __p. * If adding character causes the length to exceed max_size(), * length_error is thrown. If @a __p is beyond end of string, * out_of_range is thrown. The value of the string doesn't * change if an error is thrown. / iterator insert(iterator __p, _CharT __c) { _GLIBCXX_DEBUG_PEDASSERT(__p >= _M_ibegin() && __p <= _M_iend()); const size_type __pos = __p - _M_ibegin(); _M_replace_aux(__pos, size_type(0), size_type(1), __c); _M_rep()->_M_set_leaked(); return iterator(_M_data() + __pos); } #if __cplusplus > 201402L /* * @brief Insert a string_view. * @param __pos Iterator referencing position in string to insert at. * @param __svt The object convertible to string_view to insert. * @return Reference to this string. / template<typename _Tp> _If_sv<_Tp, basic_string&> insert(size_type __pos, const _Tp& __svt) { __sv_type __sv = __svt; return this->insert(__pos, __sv.data(), __sv.size()); } /* * @brief Insert a string_view. * @param __pos Iterator referencing position in string to insert at. * @param __svt The object convertible to string_view to insert from. * @param __pos Iterator referencing position in string_view to insert * from. * @param __n The number of characters to insert. * @return Reference to this string. / template<typename _Tp> _If_sv<_Tp, basic_string&> insert(size_type __pos1, const _Tp& __svt, size_type __pos2, size_type __n = npos) { __sv_type __sv = __svt; return this->replace(__pos1, size_type(0), __sv.data() + __sv._M_check(__pos2, "basic_string::insert"), __sv._M_limit(__pos2, __n)); } #endif // C++17 /* * @brief Remove characters. * @param __pos Index of first character to remove (default 0). * @param __n Number of characters to remove (default remainder). * @return Reference to this string. * @throw std::out_of_range If @a pos is beyond the end of this * string. * * Removes @a __n characters from this string starting at @a * __pos. The length of the string is reduced by @a __n. If * there are < @a __n characters to remove, the remainder of * the string is truncated. If @a __p is beyond end of string, * out_of_range is thrown. The value of the string doesn't * change if an error is thrown. / basic_string& erase(size_type __pos = 0, size_type __n = npos) { _M_mutate(_M_check(__pos, "basic_string::erase"), _M_limit(__pos, __n), size_type(0)); return this; } /** * @brief Remove one character. * @param __position Iterator referencing the character to remove. * @return iterator referencing same location after removal. * * Removes the character at @a __position from this string. The value * of the string doesn't change if an error is thrown. / iterator erase(iterator __position) { _GLIBCXX_DEBUG_PEDASSERT(__position >= _M_ibegin() && __position < _M_iend()); const size_type __pos = __position - _M_ibegin(); _M_mutate(__pos, size_type(1), size_type(0)); _M_rep()->_M_set_leaked(); return iterator(_M_data() + __pos); } /* * @brief Remove a range of characters. * @param __first Iterator referencing the first character to remove. * @param __last Iterator referencing the end of the range. * @return Iterator referencing location of first after removal. * * Removes the characters in the range [first,last) from this string. * The value of the string doesn't change if an error is thrown. / iterator erase(iterator __first, iterator __last); #if __cplusplus >= 201103L /* * @brief Remove the last character. * * The string must be non-empty. / void pop_back() // FIXME C++11: should be noexcept. { __glibcxx_assert(!empty()); erase(size() - 1, 1); } #endif // C++11 /* * @brief Replace characters with value from another string. * @param __pos Index of first character to replace. * @param __n Number of characters to be replaced. * @param __str String to insert. * @return Reference to this string. * @throw std::out_of_range If @a pos is beyond the end of this * string. * @throw std::length_error If new length exceeds @c max_size(). * * Removes the characters in the range [__pos,__pos+__n) from * this string. In place, the value of @a __str is inserted. * If @a __pos is beyond end of string, out_of_range is thrown. * If the length of the result exceeds max_size(), length_error * is thrown. The value of the string doesn't change if an * error is thrown. / basic_string& replace(size_type __pos, size_type __n, const basic_string& __str) { return this->replace(__pos, __n, __str._M_data(), __str.size()); } /* * @brief Replace characters with value from another string. * @param __pos1 Index of first character to replace. * @param __n1 Number of characters to be replaced. * @param __str String to insert. * @param __pos2 Index of first character of str to use. * @param __n2 Number of characters from str to use. * @return Reference to this string. * @throw std::out_of_range If @a __pos1 > size() or @a __pos2 > * __str.size(). * @throw std::length_error If new length exceeds @c max_size(). * * Removes the characters in the range [__pos1,__pos1 + n) from this * string. In place, the value of @a __str is inserted. If @a __pos is * beyond end of string, out_of_range is thrown. If the length of the * result exceeds max_size(), length_error is thrown. The value of the * string doesn't change if an error is thrown. / basic_string& replace(size_type __pos1, size_type __n1, const basic_string& __str, size_type __pos2, size_type __n2 = npos) { return this->replace(__pos1, __n1, __str._M_data() + __str._M_check(__pos2, "basic_string::replace"), __str._M_limit(__pos2, __n2)); } /* * @brief Replace characters with value of a C substring. * @param __pos Index of first character to replace. * @param __n1 Number of characters to be replaced. * @param __s C string to insert. * @param __n2 Number of characters from @a s to use. * @return Reference to this string. * @throw std::out_of_range If @a pos1 > size(). * @throw std::length_error If new length exceeds @c max_size(). * * Removes the characters in the range [__pos,__pos + __n1) * from this string. In place, the first @a __n2 characters of * @a __s are inserted, or all of @a __s if @a __n2 is too large. If * @a __pos is beyond end of string, out_of_range is thrown. If * the length of result exceeds max_size(), length_error is * thrown. The value of the string doesn't change if an error * is thrown. / basic_string& replace(size_type __pos, size_type __n1, const _CharT __s, size_type __n2); /** * @brief Replace characters with value of a C string. * @param __pos Index of first character to replace. * @param __n1 Number of characters to be replaced. * @param __s C string to insert. * @return Reference to this string. * @throw std::out_of_range If @a pos > size(). * @throw std::length_error If new length exceeds @c max_size(). * * Removes the characters in the range [__pos,__pos + __n1) * from this string. In place, the characters of @a __s are * inserted. If @a __pos is beyond end of string, out_of_range * is thrown. If the length of result exceeds max_size(), * length_error is thrown. The value of the string doesn't * change if an error is thrown. / basic_string& replace(size_type __pos, size_type __n1, const _CharT __s) { __glibcxx_requires_string(__s); return this->replace(__pos, __n1, __s, traits_type::length(__s)); } /** * @brief Replace characters with multiple characters. * @param __pos Index of first character to replace. * @param __n1 Number of characters to be replaced. * @param __n2 Number of characters to insert. * @param __c Character to insert. * @return Reference to this string. * @throw std::out_of_range If @a __pos > size(). * @throw std::length_error If new length exceeds @c max_size(). * * Removes the characters in the range [pos,pos + n1) from this * string. In place, @a __n2 copies of @a __c are inserted. * If @a __pos is beyond end of string, out_of_range is thrown. * If the length of result exceeds max_size(), length_error is * thrown. The value of the string doesn't change if an error * is thrown. / basic_string& replace(size_type __pos, size_type __n1, size_type __n2, _CharT __c) { return _M_replace_aux(_M_check(__pos, "basic_string::replace"), _M_limit(__pos, __n1), __n2, __c); } /* * @brief Replace range of characters with string. * @param __i1 Iterator referencing start of range to replace. * @param __i2 Iterator referencing end of range to replace. * @param __str String value to insert. * @return Reference to this string. * @throw std::length_error If new length exceeds @c max_size(). * * Removes the characters in the range [__i1,__i2). In place, * the value of @a __str is inserted. If the length of result * exceeds max_size(), length_error is thrown. The value of * the string doesn't change if an error is thrown. / basic_string& replace(iterator __i1, iterator __i2, const basic_string& __str) { return this->replace(__i1, __i2, __str._M_data(), __str.size()); } /* * @brief Replace range of characters with C substring. * @param __i1 Iterator referencing start of range to replace. * @param __i2 Iterator referencing end of range to replace. * @param __s C string value to insert. * @param __n Number of characters from s to insert. * @return Reference to this string. * @throw std::length_error If new length exceeds @c max_size(). * * Removes the characters in the range [__i1,__i2). In place, * the first @a __n characters of @a __s are inserted. If the * length of result exceeds max_size(), length_error is thrown. * The value of the string doesn't change if an error is * thrown. / basic_string& replace(iterator __i1, iterator __i2, const _CharT __s, size_type __n) { _GLIBCXX_DEBUG_PEDASSERT(_M_ibegin() <= __i1 && __i1 <= __i2 && __i2 <= _M_iend()); return this->replace(__i1 - _M_ibegin(), __i2 - __i1, __s, __n); } /** * @brief Replace range of characters with C string. * @param __i1 Iterator referencing start of range to replace. * @param __i2 Iterator referencing end of range to replace. * @param __s C string value to insert. * @return Reference to this string. * @throw std::length_error If new length exceeds @c max_size(). * * Removes the characters in the range [__i1,__i2). In place, * the characters of @a __s are inserted. If the length of * result exceeds max_size(), length_error is thrown. The * value of the string doesn't change if an error is thrown. / basic_string& replace(iterator __i1, iterator __i2, const _CharT __s) { __glibcxx_requires_string(__s); return this->replace(__i1, __i2, __s, traits_type::length(__s)); } /** * @brief Replace range of characters with multiple characters * @param __i1 Iterator referencing start of range to replace. * @param __i2 Iterator referencing end of range to replace. * @param __n Number of characters to insert. * @param __c Character to insert. * @return Reference to this string. * @throw std::length_error If new length exceeds @c max_size(). * * Removes the characters in the range [__i1,__i2). In place, * @a __n copies of @a __c are inserted. If the length of * result exceeds max_size(), length_error is thrown. The * value of the string doesn't change if an error is thrown. / basic_string& replace(iterator __i1, iterator __i2, size_type __n, _CharT __c) { _GLIBCXX_DEBUG_PEDASSERT(_M_ibegin() <= __i1 && __i1 <= __i2 && __i2 <= _M_iend()); return _M_replace_aux(__i1 - _M_ibegin(), __i2 - __i1, __n, __c); } /* * @brief Replace range of characters with range. * @param __i1 Iterator referencing start of range to replace. * @param __i2 Iterator referencing end of range to replace. * @param __k1 Iterator referencing start of range to insert. * @param __k2 Iterator referencing end of range to insert. * @return Reference to this string. * @throw std::length_error If new length exceeds @c max_size(). * * Removes the characters in the range [__i1,__i2). In place, * characters in the range [__k1,__k2) are inserted. If the * length of result exceeds max_size(), length_error is thrown. * The value of the string doesn't change if an error is * thrown. / template<class _InputIterator> basic_string& replace(iterator __i1, iterator __i2, _InputIterator __k1, _InputIterator __k2) { _GLIBCXX_DEBUG_PEDASSERT(_M_ibegin() <= __i1 && __i1 <= __i2 && __i2 <= _M_iend()); __glibcxx_requires_valid_range(__k1, __k2); typedef typename std::__is_integer<_InputIterator>::__type _Integral; return _M_replace_dispatch(__i1, __i2, __k1, __k2, _Integral()); } // Specializations for the common case of pointer and iterator: // useful to avoid the overhead of temporary buffering in _M_replace. basic_string& replace(iterator __i1, iterator __i2, _CharT __k1, _CharT* __k2) { _GLIBCXX_DEBUG_PEDASSERT(_M_ibegin() <= __i1 && __i1 <= __i2 && __i2 <= _M_iend()); __glibcxx_requires_valid_range(__k1, __k2); return this->replace(__i1 - _M_ibegin(), __i2 - __i1, __k1, __k2 - __k1); } basic_string& replace(iterator __i1, iterator __i2, const _CharT* __k1, const _CharT* __k2) { _GLIBCXX_DEBUG_PEDASSERT(_M_ibegin() <= __i1 && __i1 <= __i2 && __i2 <= _M_iend()); __glibcxx_requires_valid_range(__k1, __k2); return this->replace(__i1 - _M_ibegin(), __i2 - __i1, __k1, __k2 - __k1); } basic_string& replace(iterator __i1, iterator __i2, iterator __k1, iterator __k2) { _GLIBCXX_DEBUG_PEDASSERT(_M_ibegin() <= __i1 && __i1 <= __i2 && __i2 <= _M_iend()); __glibcxx_requires_valid_range(__k1, __k2); return this->replace(__i1 - _M_ibegin(), __i2 - __i1, __k1.base(), __k2 - __k1); } basic_string& replace(iterator __i1, iterator __i2, const_iterator __k1, const_iterator __k2) { _GLIBCXX_DEBUG_PEDASSERT(_M_ibegin() <= __i1 && __i1 <= __i2 && __i2 <= _M_iend()); __glibcxx_requires_valid_range(__k1, __k2); return this->replace(__i1 - _M_ibegin(), __i2 - __i1, __k1.base(), __k2 - __k1); } #if __cplusplus >= 201103L /** * @brief Replace range of characters with initializer_list. * @param __i1 Iterator referencing start of range to replace. * @param __i2 Iterator referencing end of range to replace. * @param __l The initializer_list of characters to insert. * @return Reference to this string. * @throw std::length_error If new length exceeds @c max_size(). * * Removes the characters in the range [__i1,__i2). In place, * characters in the range [__k1,__k2) are inserted. If the * length of result exceeds max_size(), length_error is thrown. * The value of the string doesn't change if an error is * thrown. / basic_string& replace(iterator __i1, iterator __i2, initializer_list<_CharT> __l) { return this->replace(__i1, __i2, __l.begin(), __l.end()); } #endif // C++11 #if __cplusplus > 201402L /* * @brief Replace range of characters with string_view. * @param __pos The position to replace at. * @param __n The number of characters to replace. * @param __svt The object convertible to string_view to insert. * @return Reference to this string. / template<typename _Tp> _If_sv<_Tp, basic_string&> replace(size_type __pos, size_type __n, const _Tp& __svt) { __sv_type __sv = __svt; return this->replace(__pos, __n, __sv.data(), __sv.size()); } /* * @brief Replace range of characters with string_view. * @param __pos1 The position to replace at. * @param __n1 The number of characters to replace. * @param __svt The object convertible to string_view to insert from. * @param __pos2 The position in the string_view to insert from. * @param __n2 The number of characters to insert. * @return Reference to this string. / template<typename _Tp> _If_sv<_Tp, basic_string&> replace(size_type __pos1, size_type __n1, const _Tp& __svt, size_type __pos2, size_type __n2 = npos) { __sv_type __sv = __svt; return this->replace(__pos1, __n1, __sv.data() + __sv._M_check(__pos2, "basic_string::replace"), __sv._M_limit(__pos2, __n2)); } /* * @brief Replace range of characters with string_view. * @param __i1 An iterator referencing the start position to replace at. * @param __i2 An iterator referencing the end position for the replace. * @param __svt The object convertible to string_view to insert from. * @return Reference to this string. / template<typename _Tp> _If_sv<_Tp, basic_string&> replace(const_iterator __i1, const_iterator __i2, const _Tp& __svt) { __sv_type __sv = __svt; return this->replace(__i1 - begin(), __i2 - __i1, __sv); } #endif // C++17 private: template<class _Integer> basic_string& _M_replace_dispatch(iterator __i1, iterator __i2, _Integer __n, _Integer __val, __true_type) { return _M_replace_aux(__i1 - _M_ibegin(), __i2 - __i1, __n, __val); } template<class _InputIterator> basic_string& _M_replace_dispatch(iterator __i1, iterator __i2, _InputIterator __k1, _InputIterator __k2, __false_type); basic_string& _M_replace_aux(size_type __pos1, size_type __n1, size_type __n2, _CharT __c); basic_string& _M_replace_safe(size_type __pos1, size_type __n1, const _CharT __s, size_type __n2); // _S_construct_aux is used to implement the 21.3.1 para 15 which // requires special behaviour if _InIter is an integral type template<class _InIterator> static _CharT* _S_construct_aux(_InIterator __beg, _InIterator __end, const _Alloc& __a, __false_type) { typedef typename iterator_traits<_InIterator>::iterator_category _Tag; return _S_construct(__beg, __end, __a, _Tag()); } // _GLIBCXX_RESOLVE_LIB_DEFECTS // 438. Ambiguity in the "do the right thing" clause template<class _Integer> static _CharT* _S_construct_aux(_Integer __beg, _Integer __end, const _Alloc& __a, __true_type) { return _S_construct_aux_2(static_cast<size_type>(__beg), __end, __a); } static _CharT* _S_construct_aux_2(size_type __req, _CharT __c, const _Alloc& __a) { return _S_construct(__req, __c, __a); } template<class _InIterator> static _CharT* _S_construct(_InIterator __beg, _InIterator __end, const _Alloc& __a) { typedef typename std::__is_integer<_InIterator>::__type _Integral; return _S_construct_aux(__beg, __end, __a, _Integral()); } // For Input Iterators, used in istreambuf_iterators, etc. template<class _InIterator> static _CharT* _S_construct(_InIterator __beg, _InIterator __end, const _Alloc& __a, input_iterator_tag); // For forward_iterators up to random_access_iterators, used for // string::iterator, _CharT, etc. template<class _FwdIterator> static _CharT _S_construct(_FwdIterator __beg, _FwdIterator __end, const _Alloc& __a, forward_iterator_tag); static _CharT* _S_construct(size_type __req, _CharT __c, const _Alloc& __a); public: /** * @brief Copy substring into C string. * @param __s C string to copy value into. * @param __n Number of characters to copy. * @param __pos Index of first character to copy. * @return Number of characters actually copied * @throw std::out_of_range If __pos > size(). * * Copies up to @a __n characters starting at @a __pos into the * C string @a __s. If @a __pos is %greater than size(), * out_of_range is thrown. / size_type copy(_CharT __s, size_type __n, size_type __pos = 0) const; /** * @brief Swap contents with another string. * @param __s String to swap with. * * Exchanges the contents of this string with that of @a __s in constant * time. / // PR 58265, this should be noexcept. void swap(basic_string& __s); // String operations: /* * @brief Return const pointer to null-terminated contents. * * This is a handle to internal data. Do not modify or dire things may * happen. / const _CharT c_str() const _GLIBCXX_NOEXCEPT { return _M_data(); } /** * @brief Return const pointer to contents. * * This is a pointer to internal data. It is undefined to modify * the contents through the returned pointer. To get a pointer that * allows modifying the contents use @c &str[0] instead, * (or in C++17 the non-const @c str.data() overload). / const _CharT data() const _GLIBCXX_NOEXCEPT { return _M_data(); } #if __cplusplus > 201402L /** * @brief Return non-const pointer to contents. * * This is a pointer to the character sequence held by the string. * Modifying the characters in the sequence is allowed. / _CharT data() noexcept { _M_leak(); return _M_data(); } #endif /** * @brief Return copy of allocator used to construct this string. / allocator_type get_allocator() const _GLIBCXX_NOEXCEPT { return _M_dataplus; } /* * @brief Find position of a C substring. * @param __s C string to locate. * @param __pos Index of character to search from. * @param __n Number of characters from @a s to search for. * @return Index of start of first occurrence. * * Starting from @a __pos, searches forward for the first @a * __n characters in @a __s within this string. If found, * returns the index where it begins. If not found, returns * npos. / size_type find(const _CharT __s, size_type __pos, size_type __n) const _GLIBCXX_NOEXCEPT; /** * @brief Find position of a string. * @param __str String to locate. * @param __pos Index of character to search from (default 0). * @return Index of start of first occurrence. * * Starting from @a __pos, searches forward for value of @a __str within * this string. If found, returns the index where it begins. If not * found, returns npos. / size_type find(const basic_string& __str, size_type __pos = 0) const _GLIBCXX_NOEXCEPT { return this->find(__str.data(), __pos, __str.size()); } /* * @brief Find position of a C string. * @param __s C string to locate. * @param __pos Index of character to search from (default 0). * @return Index of start of first occurrence. * * Starting from @a __pos, searches forward for the value of @a * __s within this string. If found, returns the index where * it begins. If not found, returns npos. / size_type find(const _CharT __s, size_type __pos = 0) const _GLIBCXX_NOEXCEPT { __glibcxx_requires_string(__s); return this->find(__s, __pos, traits_type::length(__s)); } /** * @brief Find position of a character. * @param __c Character to locate. * @param __pos Index of character to search from (default 0). * @return Index of first occurrence. * * Starting from @a __pos, searches forward for @a __c within * this string. If found, returns the index where it was * found. If not found, returns npos. / size_type find(_CharT __c, size_type __pos = 0) const _GLIBCXX_NOEXCEPT; #if __cplusplus > 201402L /* * @brief Find position of a string_view. * @param __svt The object convertible to string_view to locate. * @param __pos Index of character to search from (default 0). * @return Index of start of first occurrence. / template<typename _Tp> _If_sv<_Tp, size_type> find(const _Tp& __svt, size_type __pos = 0) const noexcept(is_same<_Tp, __sv_type>::value) { __sv_type __sv = __svt; return this->find(__sv.data(), __pos, __sv.size()); } #endif // C++17 /* * @brief Find last position of a string. * @param __str String to locate. * @param __pos Index of character to search back from (default end). * @return Index of start of last occurrence. * * Starting from @a __pos, searches backward for value of @a * __str within this string. If found, returns the index where * it begins. If not found, returns npos. / size_type rfind(const basic_string& __str, size_type __pos = npos) const _GLIBCXX_NOEXCEPT { return this->rfind(__str.data(), __pos, __str.size()); } /* * @brief Find last position of a C substring. * @param __s C string to locate. * @param __pos Index of character to search back from. * @param __n Number of characters from s to search for. * @return Index of start of last occurrence. * * Starting from @a __pos, searches backward for the first @a * __n characters in @a __s within this string. If found, * returns the index where it begins. If not found, returns * npos. / size_type rfind(const _CharT __s, size_type __pos, size_type __n) const _GLIBCXX_NOEXCEPT; /** * @brief Find last position of a C string. * @param __s C string to locate. * @param __pos Index of character to start search at (default end). * @return Index of start of last occurrence. * * Starting from @a __pos, searches backward for the value of * @a __s within this string. If found, returns the index * where it begins. If not found, returns npos. / size_type rfind(const _CharT __s, size_type __pos = npos) const _GLIBCXX_NOEXCEPT { __glibcxx_requires_string(__s); return this->rfind(__s, __pos, traits_type::length(__s)); } /** * @brief Find last position of a character. * @param __c Character to locate. * @param __pos Index of character to search back from (default end). * @return Index of last occurrence. * * Starting from @a __pos, searches backward for @a __c within * this string. If found, returns the index where it was * found. If not found, returns npos. / size_type rfind(_CharT __c, size_type __pos = npos) const _GLIBCXX_NOEXCEPT; #if __cplusplus > 201402L /* * @brief Find last position of a string_view. * @param __svt The object convertible to string_view to locate. * @param __pos Index of character to search back from (default end). * @return Index of start of last occurrence. / template<typename _Tp> _If_sv<_Tp, size_type> rfind(const _Tp& __svt, size_type __pos = npos) const noexcept(is_same<_Tp, __sv_type>::value) { __sv_type __sv = __svt; return this->rfind(__sv.data(), __pos, __sv.size()); } #endif // C++17 /* * @brief Find position of a character of string. * @param __str String containing characters to locate. * @param __pos Index of character to search from (default 0). * @return Index of first occurrence. * * Starting from @a __pos, searches forward for one of the * characters of @a __str within this string. If found, * returns the index where it was found. If not found, returns * npos. / size_type find_first_of(const basic_string& __str, size_type __pos = 0) const _GLIBCXX_NOEXCEPT { return this->find_first_of(__str.data(), __pos, __str.size()); } /* * @brief Find position of a character of C substring. * @param __s String containing characters to locate. * @param __pos Index of character to search from. * @param __n Number of characters from s to search for. * @return Index of first occurrence. * * Starting from @a __pos, searches forward for one of the * first @a __n characters of @a __s within this string. If * found, returns the index where it was found. If not found, * returns npos. / size_type find_first_of(const _CharT __s, size_type __pos, size_type __n) const _GLIBCXX_NOEXCEPT; /** * @brief Find position of a character of C string. * @param __s String containing characters to locate. * @param __pos Index of character to search from (default 0). * @return Index of first occurrence. * * Starting from @a __pos, searches forward for one of the * characters of @a __s within this string. If found, returns * the index where it was found. If not found, returns npos. / size_type find_first_of(const _CharT __s, size_type __pos = 0) const _GLIBCXX_NOEXCEPT { __glibcxx_requires_string(__s); return this->find_first_of(__s, __pos, traits_type::length(__s)); } /** * @brief Find position of a character. * @param __c Character to locate. * @param __pos Index of character to search from (default 0). * @return Index of first occurrence. * * Starting from @a __pos, searches forward for the character * @a __c within this string. If found, returns the index * where it was found. If not found, returns npos. * * Note: equivalent to find(__c, __pos). / size_type find_first_of(_CharT __c, size_type __pos = 0) const _GLIBCXX_NOEXCEPT { return this->find(__c, __pos); } #if __cplusplus > 201402L /* * @brief Find position of a character of a string_view. * @param __svt An object convertible to string_view containing * characters to locate. * @param __pos Index of character to search from (default 0). * @return Index of first occurrence. / template<typename _Tp> _If_sv<_Tp, size_type> find_first_of(const _Tp& __svt, size_type __pos = 0) const noexcept(is_same<_Tp, __sv_type>::value) { __sv_type __sv = __svt; return this->find_first_of(__sv.data(), __pos, __sv.size()); } #endif // C++17 /* * @brief Find last position of a character of string. * @param __str String containing characters to locate. * @param __pos Index of character to search back from (default end). * @return Index of last occurrence. * * Starting from @a __pos, searches backward for one of the * characters of @a __str within this string. If found, * returns the index where it was found. If not found, returns * npos. / size_type find_last_of(const basic_string& __str, size_type __pos = npos) const _GLIBCXX_NOEXCEPT { return this->find_last_of(__str.data(), __pos, __str.size()); } /* * @brief Find last position of a character of C substring. * @param __s C string containing characters to locate. * @param __pos Index of character to search back from. * @param __n Number of characters from s to search for. * @return Index of last occurrence. * * Starting from @a __pos, searches backward for one of the * first @a __n characters of @a __s within this string. If * found, returns the index where it was found. If not found, * returns npos. / size_type find_last_of(const _CharT __s, size_type __pos, size_type __n) const _GLIBCXX_NOEXCEPT; /** * @brief Find last position of a character of C string. * @param __s C string containing characters to locate. * @param __pos Index of character to search back from (default end). * @return Index of last occurrence. * * Starting from @a __pos, searches backward for one of the * characters of @a __s within this string. If found, returns * the index where it was found. If not found, returns npos. / size_type find_last_of(const _CharT __s, size_type __pos = npos) const _GLIBCXX_NOEXCEPT { __glibcxx_requires_string(__s); return this->find_last_of(__s, __pos, traits_type::length(__s)); } /** * @brief Find last position of a character. * @param __c Character to locate. * @param __pos Index of character to search back from (default end). * @return Index of last occurrence. * * Starting from @a __pos, searches backward for @a __c within * this string. If found, returns the index where it was * found. If not found, returns npos. * * Note: equivalent to rfind(__c, __pos). / size_type find_last_of(_CharT __c, size_type __pos = npos) const _GLIBCXX_NOEXCEPT { return this->rfind(__c, __pos); } #if __cplusplus > 201402L /* * @brief Find last position of a character of string. * @param __svt An object convertible to string_view containing * characters to locate. * @param __pos Index of character to search back from (default end). * @return Index of last occurrence. / template<typename _Tp> _If_sv<_Tp, size_type> find_last_of(const _Tp& __svt, size_type __pos = npos) const noexcept(is_same<_Tp, __sv_type>::value) { __sv_type __sv = __svt; return this->find_last_of(__sv.data(), __pos, __sv.size()); } #endif // C++17 /* * @brief Find position of a character not in string. * @param __str String containing characters to avoid. * @param __pos Index of character to search from (default 0). * @return Index of first occurrence. * * Starting from @a __pos, searches forward for a character not contained * in @a __str within this string. If found, returns the index where it * was found. If not found, returns npos. / size_type find_first_not_of(const basic_string& __str, size_type __pos = 0) const _GLIBCXX_NOEXCEPT { return this->find_first_not_of(__str.data(), __pos, __str.size()); } /* * @brief Find position of a character not in C substring. * @param __s C string containing characters to avoid. * @param __pos Index of character to search from. * @param __n Number of characters from __s to consider. * @return Index of first occurrence. * * Starting from @a __pos, searches forward for a character not * contained in the first @a __n characters of @a __s within * this string. If found, returns the index where it was * found. If not found, returns npos. / size_type find_first_not_of(const _CharT __s, size_type __pos, size_type __n) const _GLIBCXX_NOEXCEPT; /** * @brief Find position of a character not in C string. * @param __s C string containing characters to avoid. * @param __pos Index of character to search from (default 0). * @return Index of first occurrence. * * Starting from @a __pos, searches forward for a character not * contained in @a __s within this string. If found, returns * the index where it was found. If not found, returns npos. / size_type find_first_not_of(const _CharT __s, size_type __pos = 0) const _GLIBCXX_NOEXCEPT { __glibcxx_requires_string(__s); return this->find_first_not_of(__s, __pos, traits_type::length(__s)); } /** * @brief Find position of a different character. * @param __c Character to avoid. * @param __pos Index of character to search from (default 0). * @return Index of first occurrence. * * Starting from @a __pos, searches forward for a character * other than @a __c within this string. If found, returns the * index where it was found. If not found, returns npos. / size_type find_first_not_of(_CharT __c, size_type __pos = 0) const _GLIBCXX_NOEXCEPT; #if __cplusplus > 201402L /* * @brief Find position of a character not in a string_view. * @param __svt An object convertible to string_view containing * characters to avoid. * @param __pos Index of character to search from (default 0). * @return Index of first occurrence. / template<typename _Tp> _If_sv<_Tp, size_type> find_first_not_of(const _Tp& __svt, size_type __pos = 0) const noexcept(is_same<_Tp, __sv_type>::value) { __sv_type __sv = __svt; return this->find_first_not_of(__sv.data(), __pos, __sv.size()); } #endif // C++17 /* * @brief Find last position of a character not in string. * @param __str String containing characters to avoid. * @param __pos Index of character to search back from (default end). * @return Index of last occurrence. * * Starting from @a __pos, searches backward for a character * not contained in @a __str within this string. If found, * returns the index where it was found. If not found, returns * npos. / size_type find_last_not_of(const basic_string& __str, size_type __pos = npos) const _GLIBCXX_NOEXCEPT { return this->find_last_not_of(__str.data(), __pos, __str.size()); } /* * @brief Find last position of a character not in C substring. * @param __s C string containing characters to avoid. * @param __pos Index of character to search back from. * @param __n Number of characters from s to consider. * @return Index of last occurrence. * * Starting from @a __pos, searches backward for a character not * contained in the first @a __n characters of @a __s within this string. * If found, returns the index where it was found. If not found, * returns npos. / size_type find_last_not_of(const _CharT __s, size_type __pos, size_type __n) const _GLIBCXX_NOEXCEPT; /** * @brief Find last position of a character not in C string. * @param __s C string containing characters to avoid. * @param __pos Index of character to search back from (default end). * @return Index of last occurrence. * * Starting from @a __pos, searches backward for a character * not contained in @a __s within this string. If found, * returns the index where it was found. If not found, returns * npos. / size_type find_last_not_of(const _CharT __s, size_type __pos = npos) const _GLIBCXX_NOEXCEPT { __glibcxx_requires_string(__s); return this->find_last_not_of(__s, __pos, traits_type::length(__s)); } /** * @brief Find last position of a different character. * @param __c Character to avoid. * @param __pos Index of character to search back from (default end). * @return Index of last occurrence. * * Starting from @a __pos, searches backward for a character other than * @a __c within this string. If found, returns the index where it was * found. If not found, returns npos. / size_type find_last_not_of(_CharT __c, size_type __pos = npos) const _GLIBCXX_NOEXCEPT; #if __cplusplus > 201402L /* * @brief Find last position of a character not in a string_view. * @param __svt An object convertible to string_view containing * characters to avoid. * @param __pos Index of character to search back from (default end). * @return Index of last occurrence. / template<typename _Tp> _If_sv<_Tp, size_type> find_last_not_of(const _Tp& __svt, size_type __pos = npos) const noexcept(is_same<_Tp, __sv_type>::value) { __sv_type __sv = __svt; return this->find_last_not_of(__sv.data(), __pos, __sv.size()); } #endif // C++17 /* * @brief Get a substring. * @param __pos Index of first character (default 0). * @param __n Number of characters in substring (default remainder). * @return The new string. * @throw std::out_of_range If __pos > size(). * * Construct and return a new string using the @a __n * characters starting at @a __pos. If the string is too * short, use the remainder of the characters. If @a __pos is * beyond the end of the string, out_of_range is thrown. / basic_string substr(size_type __pos = 0, size_type __n = npos) const { return basic_string(this, _M_check(__pos, "basic_string::substr"), __n); } /** * @brief Compare to a string. * @param __str String to compare against. * @return Integer < 0, 0, or > 0. * * Returns an integer < 0 if this string is ordered before @a * __str, 0 if their values are equivalent, or > 0 if this * string is ordered after @a __str. Determines the effective * length rlen of the strings to compare as the smallest of * size() and str.size(). The function then compares the two * strings by calling traits::compare(data(), str.data(),rlen). * If the result of the comparison is nonzero returns it, * otherwise the shorter one is ordered first. / int compare(const basic_string& __str) const { const size_type __size = this->size(); const size_type __osize = __str.size(); const size_type __len = std::min(__size, __osize); int __r = traits_type::compare(_M_data(), __str.data(), __len); if (!__r) __r = _S_compare(__size, __osize); return __r; } #if __cplusplus > 201402L /* * @brief Compare to a string_view. * @param __svt An object convertible to string_view to compare against. * @return Integer < 0, 0, or > 0. / template<typename _Tp> _If_sv<_Tp, int> compare(const _Tp& __svt) const noexcept(is_same<_Tp, __sv_type>::value) { __sv_type __sv = __svt; const size_type __size = this->size(); const size_type __osize = __sv.size(); const size_type __len = std::min(__size, __osize); int __r = traits_type::compare(_M_data(), __sv.data(), __len); if (!__r) __r = _S_compare(__size, __osize); return __r; } /* * @brief Compare to a string_view. * @param __pos A position in the string to start comparing from. * @param __n The number of characters to compare. * @param __svt An object convertible to string_view to compare * against. * @return Integer < 0, 0, or > 0. / template<typename _Tp> _If_sv<_Tp, int> compare(size_type __pos, size_type __n, const _Tp& __svt) const noexcept(is_same<_Tp, __sv_type>::value) { __sv_type __sv = __svt; return __sv_type(this).substr(__pos, __n).compare(__sv); } /** * @brief Compare to a string_view. * @param __pos1 A position in the string to start comparing from. * @param __n1 The number of characters to compare. * @param __svt An object convertible to string_view to compare * against. * @param __pos2 A position in the string_view to start comparing from. * @param __n2 The number of characters to compare. * @return Integer < 0, 0, or > 0. / template<typename _Tp> _If_sv<_Tp, int> compare(size_type __pos1, size_type __n1, const _Tp& __svt, size_type __pos2, size_type __n2 = npos) const noexcept(is_same<_Tp, __sv_type>::value) { __sv_type __sv = __svt; return __sv_type(this) .substr(__pos1, __n1).compare(__sv.substr(__pos2, __n2)); } #endif // C++17 /** * @brief Compare substring to a string. * @param __pos Index of first character of substring. * @param __n Number of characters in substring. * @param __str String to compare against. * @return Integer < 0, 0, or > 0. * * Form the substring of this string from the @a __n characters * starting at @a __pos. Returns an integer < 0 if the * substring is ordered before @a __str, 0 if their values are * equivalent, or > 0 if the substring is ordered after @a * __str. Determines the effective length rlen of the strings * to compare as the smallest of the length of the substring * and @a __str.size(). The function then compares the two * strings by calling * traits::compare(substring.data(),str.data(),rlen). If the * result of the comparison is nonzero returns it, otherwise * the shorter one is ordered first. / int compare(size_type __pos, size_type __n, const basic_string& __str) const; /* * @brief Compare substring to a substring. * @param __pos1 Index of first character of substring. * @param __n1 Number of characters in substring. * @param __str String to compare against. * @param __pos2 Index of first character of substring of str. * @param __n2 Number of characters in substring of str. * @return Integer < 0, 0, or > 0. * * Form the substring of this string from the @a __n1 * characters starting at @a __pos1. Form the substring of @a * __str from the @a __n2 characters starting at @a __pos2. * Returns an integer < 0 if this substring is ordered before * the substring of @a __str, 0 if their values are equivalent, * or > 0 if this substring is ordered after the substring of * @a __str. Determines the effective length rlen of the * strings to compare as the smallest of the lengths of the * substrings. The function then compares the two strings by * calling * traits::compare(substring.data(),str.substr(pos2,n2).data(),rlen). * If the result of the comparison is nonzero returns it, * otherwise the shorter one is ordered first. / int compare(size_type __pos1, size_type __n1, const basic_string& __str, size_type __pos2, size_type __n2 = npos) const; /* * @brief Compare to a C string. * @param __s C string to compare against. * @return Integer < 0, 0, or > 0. * * Returns an integer < 0 if this string is ordered before @a __s, 0 if * their values are equivalent, or > 0 if this string is ordered after * @a __s. Determines the effective length rlen of the strings to * compare as the smallest of size() and the length of a string * constructed from @a __s. The function then compares the two strings * by calling traits::compare(data(),s,rlen). If the result of the * comparison is nonzero returns it, otherwise the shorter one is * ordered first. / int compare(const _CharT __s) const _GLIBCXX_NOEXCEPT; // _GLIBCXX_RESOLVE_LIB_DEFECTS // 5 String::compare specification questionable /** * @brief Compare substring to a C string. * @param __pos Index of first character of substring. * @param __n1 Number of characters in substring. * @param __s C string to compare against. * @return Integer < 0, 0, or > 0. * * Form the substring of this string from the @a __n1 * characters starting at @a pos. Returns an integer < 0 if * the substring is ordered before @a __s, 0 if their values * are equivalent, or > 0 if the substring is ordered after @a * __s. Determines the effective length rlen of the strings to * compare as the smallest of the length of the substring and * the length of a string constructed from @a __s. The * function then compares the two string by calling * traits::compare(substring.data(),__s,rlen). If the result of * the comparison is nonzero returns it, otherwise the shorter * one is ordered first. / int compare(size_type __pos, size_type __n1, const _CharT __s) const; /** * @brief Compare substring against a character %array. * @param __pos Index of first character of substring. * @param __n1 Number of characters in substring. * @param __s character %array to compare against. * @param __n2 Number of characters of s. * @return Integer < 0, 0, or > 0. * * Form the substring of this string from the @a __n1 * characters starting at @a __pos. Form a string from the * first @a __n2 characters of @a __s. Returns an integer < 0 * if this substring is ordered before the string from @a __s, * 0 if their values are equivalent, or > 0 if this substring * is ordered after the string from @a __s. Determines the * effective length rlen of the strings to compare as the * smallest of the length of the substring and @a __n2. The * function then compares the two strings by calling * traits::compare(substring.data(),s,rlen). If the result of * the comparison is nonzero returns it, otherwise the shorter * one is ordered first. * * NB: s must have at least n2 characters, '\\0' has * no special meaning. / int compare(size_type __pos, size_type __n1, const _CharT __s, size_type __n2) const; # ifdef _GLIBCXX_TM_TS_INTERNAL friend void ::_txnal_cow_string_C1_for_exceptions(void* that, const char* s, void* exc); friend const char* ::_txnal_cow_string_c_str(const void that); friend void ::_txnal_cow_string_D1(void that); friend void ::_txnal_cow_string_D1_commit(void that); # endif }; #endif // !_GLIBCXX_USE_CXX11_ABI #if __cpp_deduction_guides >= 201606 _GLIBCXX_BEGIN_NAMESPACE_CXX11 template<typename _InputIterator, typename _CharT = typename iterator_traits<_InputIterator>::value_type, typename _Allocator = allocator<_CharT>, typename = _RequireInputIter<_InputIterator>, typename = _RequireAllocator<_Allocator>> basic_string(_InputIterator, _InputIterator, _Allocator = _Allocator()) -> basic_string<_CharT, char_traits<_CharT>, _Allocator>; // _GLIBCXX_RESOLVE_LIB_DEFECTS // 3075. basic_string needs deduction guides from basic_string_view template<typename _CharT, typename _Traits, typename _Allocator = allocator<_CharT>, typename = _RequireAllocator<_Allocator>> basic_string(basic_string_view<_CharT, _Traits>, const _Allocator& = _Allocator()) -> basic_string<_CharT, _Traits, _Allocator>; template<typename _CharT, typename _Traits, typename _Allocator = allocator<_CharT>, typename = _RequireAllocator<_Allocator>> basic_string(basic_string_view<_CharT, _Traits>, typename basic_string<_CharT, _Traits, _Allocator>::size_type, typename basic_string<_CharT, _Traits, _Allocator>::size_type, const _Allocator& = _Allocator()) -> basic_string<_CharT, _Traits, _Allocator>; _GLIBCXX_END_NAMESPACE_CXX11 #endif // operator+ /* * @brief Concatenate two strings. * @param __lhs First string. * @param __rhs Last string. * @return New string with value of @a __lhs followed by @a __rhs. / template<typename _CharT, typename _Traits, typename _Alloc> basic_string<_CharT, _Traits, _Alloc> operator+(const basic_string<_CharT, _Traits, _Alloc>& __lhs, const basic_string<_CharT, _Traits, _Alloc>& __rhs) { basic_string<_CharT, _Traits, _Alloc> __str(__lhs); __str.append(__rhs); return __str; } /* * @brief Concatenate C string and string. * @param __lhs First string. * @param __rhs Last string. * @return New string with value of @a __lhs followed by @a __rhs. / template<typename _CharT, typename _Traits, typename _Alloc> basic_string<_CharT,_Traits,_Alloc> operator+(const _CharT __lhs, const basic_string<_CharT,_Traits,_Alloc>& __rhs); /** * @brief Concatenate character and string. * @param __lhs First string. * @param __rhs Last string. * @return New string with @a __lhs followed by @a __rhs. / template<typename _CharT, typename _Traits, typename _Alloc> basic_string<_CharT,_Traits,_Alloc> operator+(_CharT __lhs, const basic_string<_CharT,_Traits,_Alloc>& __rhs); /* * @brief Concatenate string and C string. * @param __lhs First string. * @param __rhs Last string. * @return New string with @a __lhs followed by @a __rhs. / template<typename _CharT, typename _Traits, typename _Alloc> inline basic_string<_CharT, _Traits, _Alloc> operator+(const basic_string<_CharT, _Traits, _Alloc>& __lhs, const _CharT __rhs) { basic_string<_CharT, _Traits, _Alloc> __str(__lhs); __str.append(__rhs); return __str; } /** * @brief Concatenate string and character. * @param __lhs First string. * @param __rhs Last string. * @return New string with @a __lhs followed by @a __rhs. / template<typename _CharT, typename _Traits, typename _Alloc> inline basic_string<_CharT, _Traits, _Alloc> operator+(const basic_string<_CharT, _Traits, _Alloc>& __lhs, _CharT __rhs) { typedef basic_string<_CharT, _Traits, _Alloc> __string_type; typedef typename __string_type::size_type __size_type; __string_type __str(__lhs); __str.append(__size_type(1), __rhs); return __str; } #if __cplusplus >= 201103L template<typename _CharT, typename _Traits, typename _Alloc> inline basic_string<_CharT, _Traits, _Alloc> operator+(basic_string<_CharT, _Traits, _Alloc>&& __lhs, const basic_string<_CharT, _Traits, _Alloc>& __rhs) { return std::move(__lhs.append(__rhs)); } template<typename _CharT, typename _Traits, typename _Alloc> inline basic_string<_CharT, _Traits, _Alloc> operator+(const basic_string<_CharT, _Traits, _Alloc>& __lhs, basic_string<_CharT, _Traits, _Alloc>&& __rhs) { return std::move(__rhs.insert(0, __lhs)); } template<typename _CharT, typename _Traits, typename _Alloc> inline basic_string<_CharT, _Traits, _Alloc> operator+(basic_string<_CharT, _Traits, _Alloc>&& __lhs, basic_string<_CharT, _Traits, _Alloc>&& __rhs) { const auto __size = __lhs.size() + __rhs.size(); const bool __cond = (__size > __lhs.capacity() && __size <= __rhs.capacity()); return __cond ? std::move(__rhs.insert(0, __lhs)) : std::move(__lhs.append(__rhs)); } template<typename _CharT, typename _Traits, typename _Alloc> inline basic_string<_CharT, _Traits, _Alloc> operator+(const _CharT __lhs, basic_string<_CharT, _Traits, _Alloc>&& __rhs) { return std::move(__rhs.insert(0, __lhs)); } template<typename _CharT, typename _Traits, typename _Alloc> inline basic_string<_CharT, _Traits, _Alloc> operator+(_CharT __lhs, basic_string<_CharT, _Traits, _Alloc>&& __rhs) { return std::move(__rhs.insert(0, 1, __lhs)); } template<typename _CharT, typename _Traits, typename _Alloc> inline basic_string<_CharT, _Traits, _Alloc> operator+(basic_string<_CharT, _Traits, _Alloc>&& __lhs, const _CharT* __rhs) { return std::move(__lhs.append(__rhs)); } template<typename _CharT, typename _Traits, typename _Alloc> inline basic_string<_CharT, _Traits, _Alloc> operator+(basic_string<_CharT, _Traits, _Alloc>&& __lhs, _CharT __rhs) { return std::move(__lhs.append(1, __rhs)); } #endif // operator == /** * @brief Test equivalence of two strings. * @param __lhs First string. * @param __rhs Second string. * @return True if @a __lhs.compare(@a __rhs) == 0. False otherwise. / template<typename _CharT, typename _Traits, typename _Alloc> inline bool operator==(const basic_string<_CharT, _Traits, _Alloc>& __lhs, const basic_string<_CharT, _Traits, _Alloc>& __rhs) _GLIBCXX_NOEXCEPT { return __lhs.compare(__rhs) == 0; } template<typename _CharT> inline typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value, bool>::__type operator==(const basic_string<_CharT>& __lhs, const basic_string<_CharT>& __rhs) _GLIBCXX_NOEXCEPT { return (__lhs.size() == __rhs.size() && !std::char_traits<_CharT>::compare(__lhs.data(), __rhs.data(), __lhs.size())); } /* * @brief Test equivalence of C string and string. * @param __lhs C string. * @param __rhs String. * @return True if @a __rhs.compare(@a __lhs) == 0. False otherwise. / template<typename _CharT, typename _Traits, typename _Alloc> inline bool operator==(const _CharT __lhs, const basic_string<_CharT, _Traits, _Alloc>& __rhs) { return __rhs.compare(__lhs) == 0; } /** * @brief Test equivalence of string and C string. * @param __lhs String. * @param __rhs C string. * @return True if @a __lhs.compare(@a __rhs) == 0. False otherwise. / template<typename _CharT, typename _Traits, typename _Alloc> inline bool operator==(const basic_string<_CharT, _Traits, _Alloc>& __lhs, const _CharT __rhs) { return __lhs.compare(__rhs) == 0; } // operator != /** * @brief Test difference of two strings. * @param __lhs First string. * @param __rhs Second string. * @return True if @a __lhs.compare(@a __rhs) != 0. False otherwise. / template<typename _CharT, typename _Traits, typename _Alloc> inline bool operator!=(const basic_string<_CharT, _Traits, _Alloc>& __lhs, const basic_string<_CharT, _Traits, _Alloc>& __rhs) _GLIBCXX_NOEXCEPT { return !(__lhs == __rhs); } /* * @brief Test difference of C string and string. * @param __lhs C string. * @param __rhs String. * @return True if @a __rhs.compare(@a __lhs) != 0. False otherwise. / template<typename _CharT, typename _Traits, typename _Alloc> inline bool operator!=(const _CharT __lhs, const basic_string<_CharT, _Traits, _Alloc>& __rhs) { return !(__lhs == __rhs); } /** * @brief Test difference of string and C string. * @param __lhs String. * @param __rhs C string. * @return True if @a __lhs.compare(@a __rhs) != 0. False otherwise. / template<typename _CharT, typename _Traits, typename _Alloc> inline bool operator!=(const basic_string<_CharT, _Traits, _Alloc>& __lhs, const _CharT __rhs) { return !(__lhs == __rhs); } // operator < /** * @brief Test if string precedes string. * @param __lhs First string. * @param __rhs Second string. * @return True if @a __lhs precedes @a __rhs. False otherwise. / template<typename _CharT, typename _Traits, typename _Alloc> inline bool operator<(const basic_string<_CharT, _Traits, _Alloc>& __lhs, const basic_string<_CharT, _Traits, _Alloc>& __rhs) _GLIBCXX_NOEXCEPT { return __lhs.compare(__rhs) < 0; } /* * @brief Test if string precedes C string. * @param __lhs String. * @param __rhs C string. * @return True if @a __lhs precedes @a __rhs. False otherwise. / template<typename _CharT, typename _Traits, typename _Alloc> inline bool operator<(const basic_string<_CharT, _Traits, _Alloc>& __lhs, const _CharT __rhs) { return __lhs.compare(__rhs) < 0; } /** * @brief Test if C string precedes string. * @param __lhs C string. * @param __rhs String. * @return True if @a __lhs precedes @a __rhs. False otherwise. / template<typename _CharT, typename _Traits, typename _Alloc> inline bool operator<(const _CharT __lhs, const basic_string<_CharT, _Traits, _Alloc>& __rhs) { return __rhs.compare(__lhs) > 0; } // operator > /** * @brief Test if string follows string. * @param __lhs First string. * @param __rhs Second string. * @return True if @a __lhs follows @a __rhs. False otherwise. / template<typename _CharT, typename _Traits, typename _Alloc> inline bool operator>(const basic_string<_CharT, _Traits, _Alloc>& __lhs, const basic_string<_CharT, _Traits, _Alloc>& __rhs) _GLIBCXX_NOEXCEPT { return __lhs.compare(__rhs) > 0; } /* * @brief Test if string follows C string. * @param __lhs String. * @param __rhs C string. * @return True if @a __lhs follows @a __rhs. False otherwise. / template<typename _CharT, typename _Traits, typename _Alloc> inline bool operator>(const basic_string<_CharT, _Traits, _Alloc>& __lhs, const _CharT __rhs) { return __lhs.compare(__rhs) > 0; } /** * @brief Test if C string follows string. * @param __lhs C string. * @param __rhs String. * @return True if @a __lhs follows @a __rhs. False otherwise. / template<typename _CharT, typename _Traits, typename _Alloc> inline bool operator>(const _CharT __lhs, const basic_string<_CharT, _Traits, _Alloc>& __rhs) { return __rhs.compare(__lhs) < 0; } // operator <= /** * @brief Test if string doesn't follow string. * @param __lhs First string. * @param __rhs Second string. * @return True if @a __lhs doesn't follow @a __rhs. False otherwise. / template<typename _CharT, typename _Traits, typename _Alloc> inline bool operator<=(const basic_string<_CharT, _Traits, _Alloc>& __lhs, const basic_string<_CharT, _Traits, _Alloc>& __rhs) _GLIBCXX_NOEXCEPT { return __lhs.compare(__rhs) <= 0; } /* * @brief Test if string doesn't follow C string. * @param __lhs String. * @param __rhs C string. * @return True if @a __lhs doesn't follow @a __rhs. False otherwise. / template<typename _CharT, typename _Traits, typename _Alloc> inline bool operator<=(const basic_string<_CharT, _Traits, _Alloc>& __lhs, const _CharT __rhs) { return __lhs.compare(__rhs) <= 0; } /** * @brief Test if C string doesn't follow string. * @param __lhs C string. * @param __rhs String. * @return True if @a __lhs doesn't follow @a __rhs. False otherwise. / template<typename _CharT, typename _Traits, typename _Alloc> inline bool operator<=(const _CharT __lhs, const basic_string<_CharT, _Traits, _Alloc>& __rhs) { return __rhs.compare(__lhs) >= 0; } // operator >= /** * @brief Test if string doesn't precede string. * @param __lhs First string. * @param __rhs Second string. * @return True if @a __lhs doesn't precede @a __rhs. False otherwise. / template<typename _CharT, typename _Traits, typename _Alloc> inline bool operator>=(const basic_string<_CharT, _Traits, _Alloc>& __lhs, const basic_string<_CharT, _Traits, _Alloc>& __rhs) _GLIBCXX_NOEXCEPT { return __lhs.compare(__rhs) >= 0; } /* * @brief Test if string doesn't precede C string. * @param __lhs String. * @param __rhs C string. * @return True if @a __lhs doesn't precede @a __rhs. False otherwise. / template<typename _CharT, typename _Traits, typename _Alloc> inline bool operator>=(const basic_string<_CharT, _Traits, _Alloc>& __lhs, const _CharT __rhs) { return __lhs.compare(__rhs) >= 0; } /** * @brief Test if C string doesn't precede string. * @param __lhs C string. * @param __rhs String. * @return True if @a __lhs doesn't precede @a __rhs. False otherwise. / template<typename _CharT, typename _Traits, typename _Alloc> inline bool operator>=(const _CharT __lhs, const basic_string<_CharT, _Traits, _Alloc>& __rhs) { return __rhs.compare(__lhs) <= 0; } /** * @brief Swap contents of two strings. * @param __lhs First string. * @param __rhs Second string. * * Exchanges the contents of @a __lhs and @a __rhs in constant time. / template<typename _CharT, typename _Traits, typename _Alloc> inline void swap(basic_string<_CharT, _Traits, _Alloc>& __lhs, basic_string<_CharT, _Traits, _Alloc>& __rhs) _GLIBCXX_NOEXCEPT_IF(noexcept(__lhs.swap(__rhs))) { __lhs.swap(__rhs); } /* * @brief Read stream into a string. * @param __is Input stream. * @param __str Buffer to store into. * @return Reference to the input stream. * * Stores characters from @a __is into @a __str until whitespace is * found, the end of the stream is encountered, or str.max_size() * is reached. If is.width() is non-zero, that is the limit on the * number of characters stored into @a __str. Any previous * contents of @a __str are erased. / template<typename _CharT, typename _Traits, typename _Alloc> basic_istream<_CharT, _Traits>& operator>>(basic_istream<_CharT, _Traits>& __is, basic_string<_CharT, _Traits, _Alloc>& __str); template<> basic_istream<char>& operator>>(basic_istream<char>& __is, basic_string<char>& __str); /* * @brief Write string to a stream. * @param __os Output stream. * @param __str String to write out. * @return Reference to the output stream. * * Output characters of @a __str into os following the same rules as for * writing a C string. / template<typename _CharT, typename _Traits, typename _Alloc> inline basic_ostream<_CharT, _Traits>& operator<<(basic_ostream<_CharT, _Traits>& __os, const basic_string<_CharT, _Traits, _Alloc>& __str) { // _GLIBCXX_RESOLVE_LIB_DEFECTS // 586. string inserter not a formatted function return __ostream_insert(__os, __str.data(), __str.size()); } /* * @brief Read a line from stream into a string. * @param __is Input stream. * @param __str Buffer to store into. * @param __delim Character marking end of line. * @return Reference to the input stream. * * Stores characters from @a __is into @a __str until @a __delim is * found, the end of the stream is encountered, or str.max_size() * is reached. Any previous contents of @a __str are erased. If * @a __delim is encountered, it is extracted but not stored into * @a __str. / template<typename _CharT, typename _Traits, typename _Alloc> basic_istream<_CharT, _Traits>& getline(basic_istream<_CharT, _Traits>& __is, basic_string<_CharT, _Traits, _Alloc>& __str, _CharT __delim); /* * @brief Read a line from stream into a string. * @param __is Input stream. * @param __str Buffer to store into. * @return Reference to the input stream. * * Stores characters from is into @a __str until '\n' is * found, the end of the stream is encountered, or str.max_size() * is reached. Any previous contents of @a __str are erased. If * end of line is encountered, it is extracted but not stored into * @a __str. / template<typename _CharT, typename _Traits, typename _Alloc> inline basic_istream<_CharT, _Traits>& getline(basic_istream<_CharT, _Traits>& __is, basic_string<_CharT, _Traits, _Alloc>& __str) { return std::getline(__is, __str, __is.widen('\n')); } #if __cplusplus >= 201103L /// Read a line from an rvalue stream into a string. template<typename _CharT, typename _Traits, typename _Alloc> inline basic_istream<_CharT, _Traits>& getline(basic_istream<_CharT, _Traits>&& __is, basic_string<_CharT, _Traits, _Alloc>& __str, _CharT __delim) { return std::getline(__is, __str, __delim); } /// Read a line from an rvalue stream into a string. template<typename _CharT, typename _Traits, typename _Alloc> inline basic_istream<_CharT, _Traits>& getline(basic_istream<_CharT, _Traits>&& __is, basic_string<_CharT, _Traits, _Alloc>& __str) { return std::getline(__is, __str); } #endif template<> basic_istream<char>& getline(basic_istream<char>& __in, basic_string<char>& __str, char __delim); #ifdef _GLIBCXX_USE_WCHAR_T template<> basic_istream<wchar_t>& getline(basic_istream<wchar_t>& __in, basic_string<wchar_t>& __str, wchar_t __delim); #endif _GLIBCXX_END_NAMESPACE_VERSION } // namespace #if __cplusplus >= 201103L #include <ext/string_conversions.h> namespace std _GLIBCXX_VISIBILITY(default) { _GLIBCXX_BEGIN_NAMESPACE_VERSION _GLIBCXX_BEGIN_NAMESPACE_CXX11 #if _GLIBCXX_USE_C99_STDLIB // 21.4 Numeric Conversions [string.conversions]. inline int stoi(const string& __str, size_t __idx = 0, int __base = 10) { return __gnu_cxx::__stoa<long, int>(&std::strtol, "stoi", __str.c_str(), __idx, __base); } inline long stol(const string& __str, size_t* __idx = 0, int __base = 10) { return __gnu_cxx::__stoa(&std::strtol, "stol", __str.c_str(), __idx, __base); } inline unsigned long stoul(const string& __str, size_t* __idx = 0, int __base = 10) { return __gnu_cxx::__stoa(&std::strtoul, "stoul", __str.c_str(), __idx, __base); } inline long long stoll(const string& __str, size_t* __idx = 0, int __base = 10) { return __gnu_cxx::__stoa(&std::strtoll, "stoll", __str.c_str(), __idx, __base); } inline unsigned long long stoull(const string& __str, size_t* __idx = 0, int __base = 10) { return __gnu_cxx::__stoa(&std::strtoull, "stoull", __str.c_str(), __idx, __base); } // NB: strtof vs strtod. inline float stof(const string& __str, size_t* __idx = 0) { return __gnu_cxx::__stoa(&std::strtof, "stof", __str.c_str(), __idx); } inline double stod(const string& __str, size_t* __idx = 0) { return __gnu_cxx::__stoa(&std::strtod, "stod", __str.c_str(), __idx); } inline long double stold(const string& __str, size_t* __idx = 0) { return __gnu_cxx::__stoa(&std::strtold, "stold", __str.c_str(), __idx); } #endif // _GLIBCXX_USE_C99_STDLIB #if _GLIBCXX_USE_C99_STDIO // NB: (v)snprintf vs sprintf. // DR 1261. inline string to_string(int __val) { return __gnu_cxx::__to_xstring<string>(&std::vsnprintf, 4 * sizeof(int), "%d", __val); } inline string to_string(unsigned __val) { return __gnu_cxx::__to_xstring<string>(&std::vsnprintf, 4 * sizeof(unsigned), "%u", __val); } inline string to_string(long __val) { return __gnu_cxx::__to_xstring<string>(&std::vsnprintf, 4 * sizeof(long), "%ld", __val); } inline string to_string(unsigned long __val) { return __gnu_cxx::__to_xstring<string>(&std::vsnprintf, 4 * sizeof(unsigned long), "%lu", __val); } inline string to_string(long long __val) { return __gnu_cxx::__to_xstring<string>(&std::vsnprintf, 4 * sizeof(long long), "%lld", __val); } inline string to_string(unsigned long long __val) { return __gnu_cxx::__to_xstring<string>(&std::vsnprintf, 4 * sizeof(unsigned long long), "%llu", __val); } inline string to_string(float __val) { const int __n = __gnu_cxx::__numeric_traits<float>::__max_exponent10 + 20; return __gnu_cxx::__to_xstring<string>(&std::vsnprintf, __n, "%f", __val); } inline string to_string(double __val) { const int __n = __gnu_cxx::__numeric_traits<double>::__max_exponent10 + 20; return __gnu_cxx::__to_xstring<string>(&std::vsnprintf, __n, "%f", __val); } inline string to_string(long double __val) { const int __n = __gnu_cxx::__numeric_traits<long double>::__max_exponent10 + 20; return __gnu_cxx::__to_xstring<string>(&std::vsnprintf, __n, "%Lf", __val); } #endif // _GLIBCXX_USE_C99_STDIO #if defined(_GLIBCXX_USE_WCHAR_T) && _GLIBCXX_USE_C99_WCHAR inline int stoi(const wstring& __str, size_t* __idx = 0, int __base = 10) { return __gnu_cxx::__stoa<long, int>(&std::wcstol, "stoi", __str.c_str(), __idx, __base); } inline long stol(const wstring& __str, size_t* __idx = 0, int __base = 10) { return __gnu_cxx::__stoa(&std::wcstol, "stol", __str.c_str(), __idx, __base); } inline unsigned long stoul(const wstring& __str, size_t* __idx = 0, int __base = 10) { return __gnu_cxx::__stoa(&std::wcstoul, "stoul", __str.c_str(), __idx, __base); } inline long long stoll(const wstring& __str, size_t* __idx = 0, int __base = 10) { return __gnu_cxx::__stoa(&std::wcstoll, "stoll", __str.c_str(), __idx, __base); } inline unsigned long long stoull(const wstring& __str, size_t* __idx = 0, int __base = 10) { return __gnu_cxx::__stoa(&std::wcstoull, "stoull", __str.c_str(), __idx, __base); } // NB: wcstof vs wcstod. inline float stof(const wstring& __str, size_t* __idx = 0) { return __gnu_cxx::__stoa(&std::wcstof, "stof", __str.c_str(), __idx); } inline double stod(const wstring& __str, size_t* __idx = 0) { return __gnu_cxx::__stoa(&std::wcstod, "stod", __str.c_str(), __idx); } inline long double stold(const wstring& __str, size_t* __idx = 0) { return __gnu_cxx::__stoa(&std::wcstold, "stold", __str.c_str(), __idx); } #ifndef _GLIBCXX_HAVE_BROKEN_VSWPRINTF // DR 1261. inline wstring to_wstring(int __val) { return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf, 4 * sizeof(int), L"%d", __val); } inline wstring to_wstring(unsigned __val) { return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf, 4 * sizeof(unsigned), L"%u", __val); } inline wstring to_wstring(long __val) { return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf, 4 * sizeof(long), L"%ld", __val); } inline wstring to_wstring(unsigned long __val) { return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf, 4 * sizeof(unsigned long), L"%lu", __val); } inline wstring to_wstring(long long __val) { return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf, 4 * sizeof(long long), L"%lld", __val); } inline wstring to_wstring(unsigned long long __val) { return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf, 4 * sizeof(unsigned long long), L"%llu", __val); } inline wstring to_wstring(float __val) { const int __n = __gnu_cxx::__numeric_traits<float>::__max_exponent10 + 20; return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf, __n, L"%f", __val); } inline wstring to_wstring(double __val) { const int __n = __gnu_cxx::__numeric_traits<double>::__max_exponent10 + 20; return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf, __n, L"%f", __val); } inline wstring to_wstring(long double __val) { const int __n = __gnu_cxx::__numeric_traits<long double>::__max_exponent10 + 20; return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf, __n, L"%Lf", __val); } #endif // _GLIBCXX_HAVE_BROKEN_VSWPRINTF #endif // _GLIBCXX_USE_WCHAR_T && _GLIBCXX_USE_C99_WCHAR _GLIBCXX_END_NAMESPACE_CXX11 _GLIBCXX_END_NAMESPACE_VERSION } // namespace #endif /* C++11 / #if __cplusplus >= 201103L #include <bits/functional_hash.h> namespace std _GLIBCXX_VISIBILITY(default) { _GLIBCXX_BEGIN_NAMESPACE_VERSION // DR 1182. #ifndef _GLIBCXX_COMPATIBILITY_CXX0X /// std::hash specialization for string. template<> struct hash<string> : public __hash_base<size_t, string> { size_t operator()(const string& __s) const noexcept { return std::_Hash_impl::hash(__s.data(), __s.length()); } }; template<> struct __is_fast_hash<hash<string>> : std::false_type { }; #ifdef _GLIBCXX_USE_WCHAR_T /// std::hash specialization for wstring. template<> struct hash<wstring> : public __hash_base<size_t, wstring> { size_t operator()(const wstring& __s) const noexcept { return std::_Hash_impl::hash(__s.data(), __s.length() sizeof(wchar_t)); } }; template<> struct __is_fast_hash<hash<wstring>> : std::false_type { }; #endif #endif /* _GLIBCXX_COMPATIBILITY_CXX0X / #ifdef _GLIBCXX_USE_C99_STDINT_TR1 /// std::hash specialization for u16string. template<> struct hash<u16string> : public __hash_base<size_t, u16string> { size_t operator()(const u16string& __s) const noexcept { return std::_Hash_impl::hash(__s.data(), __s.length() sizeof(char16_t)); } }; template<> struct __is_fast_hash<hash<u16string>> : std::false_type { }; /// std::hash specialization for u32string. template<> struct hash<u32string> : public __hash_base<size_t, u32string> { size_t operator()(const u32string& __s) const noexcept { return std::_Hash_impl::hash(__s.data(), __s.length() * sizeof(char32_t)); } }; template<> struct __is_fast_hash<hash<u32string>> : std::false_type { }; #endif #if __cplusplus > 201103L #define __cpp_lib_string_udls 201304 inline namespace literals { inline namespace string_literals { #pragma GCC diagnostic push #pragma GCC diagnostic ignored "-Wliteral-suffix" _GLIBCXX_DEFAULT_ABI_TAG inline basic_string<char> operator""s(const char* __str, size_t __len) { return basic_string<char>{__str, __len}; } #ifdef _GLIBCXX_USE_WCHAR_T _GLIBCXX_DEFAULT_ABI_TAG inline basic_string<wchar_t> operator""s(const wchar_t* __str, size_t __len) { return basic_string<wchar_t>{__str, __len}; } #endif #ifdef _GLIBCXX_USE_C99_STDINT_TR1 _GLIBCXX_DEFAULT_ABI_TAG inline basic_string<char16_t> operator""s(const char16_t* __str, size_t __len) { return basic_string<char16_t>{__str, __len}; } _GLIBCXX_DEFAULT_ABI_TAG inline basic_string<char32_t> operator""s(const char32_t* __str, size_t __len) { return basic_string<char32_t>{__str, __len}; } #endif #pragma GCC diagnostic pop } // inline namespace string_literals } // inline namespace literals #endif // __cplusplus > 201103L _GLIBCXX_END_NAMESPACE_VERSION } // namespace std #endif // C++11 #endif /* _BASIC_STRING_H */ Back

Edit File : basic_string.h | Size : 237.01 KB

// Components for manipulating sequences of characters -*- C++ -*-

// Copyright (C) 1997-2018 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/atomicity.h>
#include <ext/alloc_traits.h>
#include <debug/debug.h>

#if __cplusplus >= 201103L
#include <initializer_list>
#endif

#if __cplusplus > 201402L
# include <string_view>
#endif

namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION

#if __cplusplus >= 201703L
// Support P0426R1 changes to char_traits in C++17.
# define __cpp_lib_constexpr_string 201611L
#endif

#if _GLIBCXX_USE_CXX11_ABI
_GLIBCXX_BEGIN_NAMESPACE_CXX11
  /**
   *  @class basic_string basic_string.h <string>
   *  @brief  Managing sequences of characters and character-like objects.
   *
   *  @ingroup strings
   *  @ingroup sequences
   *
   *  @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
    {
      typedef typename __gnu_cxx::__alloc_traits<_Alloc>::template
	rebind<_CharT>::other _Char_alloc_type;
      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);

private:
      // type used for positions in insert, erase etc.
#if __cplusplus < 201103L
      typedef iterator __const_iterator;
#else
      typedef const_iterator __const_iterator;
#endif

#if __cplusplus > 201402L
      // 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.
      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
      {
	explicit __sv_wrapper(__sv_type __sv) noexcept : _M_sv(__sv) { }
	__sv_type _M_sv;
      };
#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
	_Alloc_hider(pointer __dat, const _Alloc& __a)
	: allocator_type(__a), _M_p(__dat) { }

_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;
      };

void
      _M_data(pointer __p)
      { _M_dataplus._M_p = __p; }

void
      _M_length(size_type __length)
      { _M_string_length = __length; }

pointer
      _M_data() const
      { return _M_dataplus._M_p; }

pointer
      _M_local_data()
      {
#if __cplusplus >= 201103L
	return std::pointer_traits<pointer>::pointer_to(*_M_local_buf);
#else
	return pointer(_M_local_buf);
#endif
      }

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
      }

void
      _M_capacity(size_type __capacity)
      { _M_allocated_capacity = __capacity; }

void
      _M_set_length(size_type __n)
      {
	_M_length(__n);
	traits_type::assign(_M_data()[__n], _CharT());
      }

bool
      _M_is_local() const
      { return _M_data() == _M_local_data(); }

// Create & Destroy
      pointer
      _M_create(size_type&, size_type);

void
      _M_dispose()
      {
	if (!_M_is_local())
	  _M_destroy(_M_allocated_capacity);
      }

void
      _M_destroy(size_type __size) throw()
      { _Alloc_traits::deallocate(_M_get_allocator(), _M_data(), __size + 1); }

// _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); }

template<typename _InIterator>
        void
        _M_construct(_InIterator __beg, _InIterator __end)
	{
	  typedef typename std::__is_integer<_InIterator>::__type _Integral;
	  _M_construct_aux(__beg, __end, _Integral());
        }

// For Input Iterators, used in istreambuf_iterators, etc.
      template<typename _InIterator>
        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>
        void
        _M_construct(_FwdIterator __beg, _FwdIterator __end,
		     std::forward_iterator_tag);

void
      _M_construct(size_type __req, _CharT __c);

allocator_type&
      _M_get_allocator()
      { return _M_dataplus; }

const allocator_type&
      _M_get_allocator() const
      { return _M_dataplus; }

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

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;
      }

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.
      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.
      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);
      }

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);
      }

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>
        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.
	}

static void
      _S_copy_chars(_CharT* __p, iterator __k1, iterator __k2) _GLIBCXX_NOEXCEPT
      { _S_copy_chars(__p, __k1.base(), __k2.base()); }

static void
      _S_copy_chars(_CharT* __p, const_iterator __k1, const_iterator __k2)
      _GLIBCXX_NOEXCEPT
      { _S_copy_chars(__p, __k1.base(), __k2.base()); }

static void
      _S_copy_chars(_CharT* __p, _CharT* __k1, _CharT* __k2) _GLIBCXX_NOEXCEPT
      { _S_copy(__p, __k1, __k2 - __k1); }

static void
      _S_copy_chars(_CharT* __p, const _CharT* __k1, const _CharT* __k2)
      _GLIBCXX_NOEXCEPT
      { _S_copy(__p, __k1, __k2 - __k1); }

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);
      }

void
      _M_assign(const basic_string&);

void
      _M_mutate(size_type __pos, size_type __len1, const _CharT* __s,
		size_type __len2);

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.
       */
      basic_string()
      _GLIBCXX_NOEXCEPT_IF(is_nothrow_default_constructible<_Alloc>::value)
      : _M_dataplus(_M_local_data())
      { _M_set_length(0); }

/**
       *  @brief  Construct an empty string using allocator @a a.
       */
      explicit
      basic_string(const _Alloc& __a) _GLIBCXX_NOEXCEPT
      : _M_dataplus(_M_local_data(), __a)
      { _M_set_length(0); }

/**
       *  @brief  Construct string with copy of value of @a __str.
       *  @param  __str  Source string.
       */
      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()); }

// _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.
       */
      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));
      }

/**
       *  @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.
       */
      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));
      }

/**
       *  @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.
       */
      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));
      }

/**
       *  @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
      basic_string(const _CharT* __s, const _Alloc& __a = _Alloc())
      : _M_dataplus(_M_local_data(), __a)
      { _M_construct(__s, __s ? __s + traits_type::length(__s) : __s+npos); }

/**
       *  @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
      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.
       **/
      basic_string(basic_string&& __str) noexcept
      : _M_dataplus(_M_local_data(), std::move(__str._M_get_allocator()))
      {
	if (__str._M_is_local())
	  {
	    traits_type::copy(_M_local_buf, __str._M_local_buf,
			      _S_local_capacity + 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_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).
       */
      basic_string(initializer_list<_CharT> __l, const _Alloc& __a = _Alloc())
      : _M_dataplus(_M_local_data(), __a)
      { _M_construct(__l.begin(), __l.end()); }

basic_string(const basic_string& __str, const _Alloc& __a)
      : _M_dataplus(_M_local_data(), __a)
      { _M_construct(__str.begin(), __str.end()); }

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())
	  {
	    traits_type::copy(_M_local_buf, __str._M_local_buf,
			      _S_local_capacity + 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_local_buf);
	    __str._M_set_length(0);
	  }
	else
	  _M_construct(__str.begin(), __str.end());
      }

#endif // C++11

/**
       *  @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
        basic_string(_InputIterator __beg, _InputIterator __end,
		     const _Alloc& __a = _Alloc())
	: _M_dataplus(_M_local_data(), __a)
	{ _M_construct(__beg, __end); }

#if __cplusplus > 201402L
      /**
       *  @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 = _If_sv<_Tp, void>>
	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>>
	explicit
	basic_string(const _Tp& __t, const _Alloc& __a = _Alloc())
	: basic_string(__sv_wrapper(_S_to_string_view(__t)), __a) { }

/**
       *  @brief  Only internally used: Construct string from a string view
       *          wrapper.
       *  @param  __svw  string view wrapper.
       *  @param  __a  Allocator to use.
       */
      explicit
      basic_string(__sv_wrapper __svw, const _Alloc& __a)
      : basic_string(__svw._M_sv.data(), __svw._M_sv.size(), __a) { }
#endif // C++17

/**
       *  @brief  Destroy the string instance.
       */
      ~basic_string()
      { _M_dispose(); }

/**
       *  @brief  Assign the value of @a str to this string.
       *  @param  __str  Source string.
       */
      basic_string&
      operator=(const basic_string& __str)
      {
#if __cplusplus >= 201103L
	if (_Alloc_traits::_S_propagate_on_copy_assign())
	  {
	    if (!_Alloc_traits::_S_always_equal() && !_M_is_local()
		&& _M_get_allocator() != __str._M_get_allocator())
	      {
		// Propagating allocator cannot free existing storage so must
		// deallocate it before replacing current allocator.
		if (__str.size() <= _S_local_capacity)
		  {
		    _M_destroy(_M_allocated_capacity);
		    _M_data(_M_local_data());
		    _M_set_length(0);
		  }
		else
		  {
		    const auto __len = __str.size();
		    auto __alloc = __str._M_get_allocator();
		    // If this allocation throws there are no effects:
		    auto __ptr = _Alloc_traits::allocate(__alloc, __len + 1);
		    _M_destroy(_M_allocated_capacity);
		    _M_data(__ptr);
		    _M_capacity(__len);
		    _M_set_length(__len);
		  }
	      }
	    std::__alloc_on_copy(_M_get_allocator(), __str._M_get_allocator());
	  }
#endif
	return this->assign(__str);
      }

/**
       *  @brief  Copy contents of @a s into this string.
       *  @param  __s  Source null-terminated string.
       */
      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.
       */
      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.
       **/
      // PR 58265, this should be noexcept.
      // _GLIBCXX_RESOLVE_LIB_DEFECTS
      // 2063. Contradictory requirements for string move assignment
      basic_string&
      operator=(basic_string&& __str)
      noexcept(_Alloc_traits::_S_nothrow_move())
      {
	if (!_M_is_local() && _Alloc_traits::_S_propagate_on_move_assign()
	    && !_Alloc_traits::_S_always_equal()
	    && _M_get_allocator() != __str._M_get_allocator())
	  {
	    // 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.
	    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()
	    || _Alloc_traits::_S_always_equal()
	    || _M_get_allocator() == __str._M_get_allocator())
	  {
	    // Just move the allocated pointer, our allocator can free it.
	    pointer __data = nullptr;
	    size_type __capacity;
	    if (!_M_is_local())
	      {
		if (_Alloc_traits::_S_always_equal())
		  {
		    // __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_local_buf);
	  }
	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.
       */
      basic_string&
      operator=(initializer_list<_CharT> __l)
      {
	this->assign(__l.begin(), __l.size());
	return *this;
      }
#endif // C++11

#if __cplusplus > 201402L
      /**
       *  @brief  Set value to string constructed from a string_view.
       *  @param  __svt  An object convertible to string_view.
       */
     template<typename _Tp>
       _If_sv<_Tp, basic_string&>
       operator=(const _Tp& __svt)
       { return this->assign(__svt); }

/**
       *  @brief  Convert to a string_view.
       *  @return A string_view.
       */
      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.
       */
      iterator
      begin() _GLIBCXX_NOEXCEPT
      { return iterator(_M_data()); }

/**
       *  Returns a read-only (constant) iterator that points to the first
       *  character in the %string.
       */
      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.
       */
      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.
       */
      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.
       */
      reverse_iterator
      rbegin() _GLIBCXX_NOEXCEPT
      { return reverse_iterator(this->end()); }

/**
       *  Returns a read-only (constant) reverse iterator that points
       *  to the last character in the %string.  Iteration is done in
       *  reverse element order.
       */
      const_reverse_iterator
      rbegin() const _GLIBCXX_NOEXCEPT
      { return const_reverse_iterator(this->end()); }

/**
       *  Returns a read/write reverse iterator that points to one before the
       *  first character in the %string.  Iteration is done in reverse
       *  element order.
       */
      reverse_iterator
      rend() _GLIBCXX_NOEXCEPT
      { return reverse_iterator(this->begin()); }

/**
       *  Returns a read-only (constant) reverse iterator that points
       *  to one before the first character in the %string.  Iteration
       *  is done in reverse element order.
       */
      const_reverse_iterator
      rend() const _GLIBCXX_NOEXCEPT
      { return const_reverse_iterator(this->begin()); }

#if __cplusplus >= 201103L
      /**
       *  Returns a read-only (constant) iterator that points to the first
       *  character in the %string.
       */
      const_iterator
      cbegin() const noexcept
      { return const_iterator(this->_M_data()); }

/**
       *  Returns a read-only (constant) iterator that points one past the
       *  last character in the %string.
       */
      const_iterator
      cend() const noexcept
      { return const_iterator(this->_M_data() + this->size()); }

/**
       *  Returns a read-only (constant) reverse iterator that points
       *  to the last character in the %string.  Iteration is done in
       *  reverse element order.
       */
      const_reverse_iterator
      crbegin() const noexcept
      { return const_reverse_iterator(this->end()); }

/**
       *  Returns a read-only (constant) reverse iterator that points
       *  to one before the first character in the %string.  Iteration
       *  is done in reverse element order.
       */
      const_reverse_iterator
      crend() const noexcept
      { return const_reverse_iterator(this->begin()); }
#endif

public:
      // Capacity:
      ///  Returns the number of characters in the string, not including any
      ///  null-termination.
      size_type
      size() const _GLIBCXX_NOEXCEPT
      { return _M_string_length; }

///  Returns the number of characters in the string, not including any
      ///  null-termination.
      size_type
      length() const _GLIBCXX_NOEXCEPT
      { return _M_string_length; }

///  Returns the size() of the largest possible %string.
      size_type
      max_size() const _GLIBCXX_NOEXCEPT
      { return (_Alloc_traits::max_size(_M_get_allocator()) - 1) / 2; }

/**
       *  @brief  Resizes the %string to the specified number of characters.
       *  @param  __n  Number of characters the %string should contain.
       *  @param  __c  Character to fill any new elements.
       *
       *  This function will %resize the %string to the specified
       *  number of characters.  If the number is smaller than the
       *  %string's current size the %string is truncated, otherwise
       *  the %string is extended and new elements are %set to @a __c.
       */
      void
      resize(size_type __n, _CharT __c);

/**
       *  @brief  Resizes the %string to the specified number of characters.
       *  @param  __n  Number of characters the %string should contain.
       *
       *  This function will resize the %string to the specified length.  If
       *  the new size is smaller than the %string's current size the %string
       *  is truncated, otherwise the %string is extended and new characters
       *  are default-constructed.  For basic types such as char, this means
       *  setting them to 0.
       */
      void
      resize(size_type __n)
      { this->resize(__n, _CharT()); }

#if __cplusplus >= 201103L
      ///  A non-binding request to reduce capacity() to size().
      void
      shrink_to_fit() noexcept
      {
#if __cpp_exceptions
	if (capacity() > size())
	  {
	    try
	      { reserve(0); }
	    catch(...)
	      { }
	  }
#endif
      }
#endif

/**
       *  Returns the total number of characters that the %string can hold
       *  before needing to allocate more memory.
       */
      size_type
      capacity() const _GLIBCXX_NOEXCEPT
      {
	return _M_is_local() ? size_type(_S_local_capacity)
	                     : _M_allocated_capacity;
      }

/**
       *  @brief  Attempt to preallocate enough memory for specified number of
       *          characters.
       *  @param  __res_arg  Number of characters required.
       *  @throw  std::length_error  If @a __res_arg exceeds @c max_size().
       *
       *  This function attempts to reserve enough memory for the
       *  %string to hold the specified number of characters.  If the
       *  number requested is more than max_size(), length_error is
       *  thrown.
       *
       *  The advantage of this function is that if optimal code is a
       *  necessity and the user can determine the string length that will be
       *  required, the user can reserve the memory in %advance, and thus
       *  prevent a possible reallocation of memory and copying of %string
       *  data.
       */
      void
      reserve(size_type __res_arg = 0);

/**
       *  Erases the string, making it empty.
       */
      void
      clear() _GLIBCXX_NOEXCEPT
      { _M_set_length(0); }

/**
       *  Returns true if the %string is empty.  Equivalent to 
       *  <code>*this == ""</code>.
       */
      bool
      empty() const _GLIBCXX_NOEXCEPT
      { return this->size() == 0; }

// Element access:
      /**
       *  @brief  Subscript access to the data contained in the %string.
       *  @param  __pos  The index of the character to access.
       *  @return  Read-only (constant) reference to the character.
       *
       *  This operator allows for easy, array-style, data access.
       *  Note that data access with this operator is unchecked and
       *  out_of_range lookups are not defined. (For checked lookups
       *  see at().)
       */
      const_reference
      operator[] (size_type __pos) const _GLIBCXX_NOEXCEPT
      {
	__glibcxx_assert(__pos <= size());
	return _M_data()[__pos];
      }

/**
       *  @brief  Subscript access to the data contained in the %string.
       *  @param  __pos  The index of the character to access.
       *  @return  Read/write reference to the character.
       *
       *  This operator allows for easy, array-style, data access.
       *  Note that data access with this operator is unchecked and
       *  out_of_range lookups are not defined. (For checked lookups
       *  see at().)
       */
      reference
      operator[](size_type __pos)
      {
        // Allow pos == size() both in C++98 mode, as v3 extension,
	// and in C++11 mode.
	__glibcxx_assert(__pos <= size());
        // In pedantic mode be strict in C++98 mode.
	_GLIBCXX_DEBUG_PEDASSERT(__cplusplus >= 201103L || __pos < size());
	return _M_data()[__pos];
      }

/**
       *  @brief  Provides access to the data contained in the %string.
       *  @param __n The index of the character to access.
       *  @return  Read-only (const) reference to the character.
       *  @throw  std::out_of_range  If @a n is an invalid index.
       *
       *  This function provides for safer data access.  The parameter is
       *  first checked that it is in the range of the string.  The function
       *  throws out_of_range if the check fails.
       */
      const_reference
      at(size_type __n) const
      {
	if (__n >= this->size())
	  __throw_out_of_range_fmt(__N("basic_string::at: __n "
				       "(which is %zu) >= this->size() "
				       "(which is %zu)"),
				   __n, this->size());
	return _M_data()[__n];
      }

/**
       *  @brief  Provides access to the data contained in the %string.
       *  @param __n The index of the character to access.
       *  @return  Read/write reference to the character.
       *  @throw  std::out_of_range  If @a n is an invalid index.
       *
       *  This function provides for safer data access.  The parameter is
       *  first checked that it is in the range of the string.  The function
       *  throws out_of_range if the check fails.
       */
      reference
      at(size_type __n)
      {
	if (__n >= size())
	  __throw_out_of_range_fmt(__N("basic_string::at: __n "
				       "(which is %zu) >= this->size() "
				       "(which is %zu)"),
				   __n, this->size());
	return _M_data()[__n];
      }

#if __cplusplus >= 201103L
      /**
       *  Returns a read/write reference to the data at the first
       *  element of the %string.
       */
      reference
      front() noexcept
      {
	__glibcxx_assert(!empty());
	return operator[](0);
      }

/**
       *  Returns a read-only (constant) reference to the data at the first
       *  element of the %string.
       */
      const_reference
      front() const noexcept
      {
	__glibcxx_assert(!empty());
	return operator[](0);
      }

/**
       *  Returns a read/write reference to the data at the last
       *  element of the %string.
       */
      reference
      back() noexcept
      {
	__glibcxx_assert(!empty());
	return operator[](this->size() - 1);
      }

/**
       *  Returns a read-only (constant) reference to the data at the
       *  last element of the %string.
       */
      const_reference
      back() const noexcept
      {
	__glibcxx_assert(!empty());
	return operator[](this->size() - 1);
      }
#endif

// Modifiers:
      /**
       *  @brief  Append a string to this string.
       *  @param __str  The string to append.
       *  @return  Reference to this string.
       */
      basic_string&
      operator+=(const basic_string& __str)
      { return this->append(__str); }

/**
       *  @brief  Append a C string.
       *  @param __s  The C string to append.
       *  @return  Reference to this string.
       */
      basic_string&
      operator+=(const _CharT* __s)
      { return this->append(__s); }

/**
       *  @brief  Append a character.
       *  @param __c  The character to append.
       *  @return  Reference to this string.
       */
      basic_string&
      operator+=(_CharT __c)
      {
	this->push_back(__c);
	return *this;
      }

#if __cplusplus >= 201103L
      /**
       *  @brief  Append an initializer_list of characters.
       *  @param __l  The initializer_list of characters to be appended.
       *  @return  Reference to this string.
       */
      basic_string&
      operator+=(initializer_list<_CharT> __l)
      { return this->append(__l.begin(), __l.size()); }
#endif // C++11

#if __cplusplus > 201402L
      /**
       *  @brief  Append a string_view.
       *  @param __svt  An object convertible to string_view to be appended.
       *  @return  Reference to this string.
       */
      template<typename _Tp>
	_If_sv<_Tp, basic_string&>
	operator+=(const _Tp& __svt)
	{ return this->append(__svt); }
#endif // C++17

/**
       *  @brief  Append a string to this string.
       *  @param __str  The string to append.
       *  @return  Reference to this string.
       */
      basic_string&
      append(const basic_string& __str)
      { return _M_append(__str._M_data(), __str.size()); }

/**
       *  @brief  Append a substring.
       *  @param __str  The string to append.
       *  @param __pos  Index of the first character of str to append.
       *  @param __n  The number of characters to append.
       *  @return  Reference to this string.
       *  @throw  std::out_of_range if @a __pos is not a valid index.
       *
       *  This function appends @a __n characters from @a __str
       *  starting at @a __pos to this string.  If @a __n is is larger
       *  than the number of available characters in @a __str, the
       *  remainder of @a __str is appended.
       */
      basic_string&
      append(const basic_string& __str, size_type __pos, size_type __n = npos)
      { return _M_append(__str._M_data()
			 + __str._M_check(__pos, "basic_string::append"),
			 __str._M_limit(__pos, __n)); }

/**
       *  @brief  Append a C substring.
       *  @param __s  The C string to append.
       *  @param __n  The number of characters to append.
       *  @return  Reference to this string.
       */
      basic_string&
      append(const _CharT* __s, size_type __n)
      {
	__glibcxx_requires_string_len(__s, __n);
	_M_check_length(size_type(0), __n, "basic_string::append");
	return _M_append(__s, __n);
      }

/**
       *  @brief  Append a C string.
       *  @param __s  The C string to append.
       *  @return  Reference to this string.
       */
      basic_string&
      append(const _CharT* __s)
      {
	__glibcxx_requires_string(__s);
	const size_type __n = traits_type::length(__s);
	_M_check_length(size_type(0), __n, "basic_string::append");
	return _M_append(__s, __n);
      }

/**
       *  @brief  Append multiple characters.
       *  @param __n  The number of characters to append.
       *  @param __c  The character to use.
       *  @return  Reference to this string.
       *
       *  Appends __n copies of __c to this string.
       */
      basic_string&
      append(size_type __n, _CharT __c)
      { return _M_replace_aux(this->size(), size_type(0), __n, __c); }

#if __cplusplus >= 201103L
      /**
       *  @brief  Append an initializer_list of characters.
       *  @param __l  The initializer_list of characters to append.
       *  @return  Reference to this string.
       */
      basic_string&
      append(initializer_list<_CharT> __l)
      { return this->append(__l.begin(), __l.size()); }
#endif // C++11

/**
       *  @brief  Append a range of characters.
       *  @param __first  Iterator referencing the first character to append.
       *  @param __last  Iterator marking the end of the range.
       *  @return  Reference to this string.
       *
       *  Appends characters in the range [__first,__last) to this string.
       */
#if __cplusplus >= 201103L
      template<class _InputIterator,
	       typename = std::_RequireInputIter<_InputIterator>>
#else
      template<class _InputIterator>
#endif
        basic_string&
        append(_InputIterator __first, _InputIterator __last)
        { return this->replace(end(), end(), __first, __last); }

#if __cplusplus > 201402L
      /**
       *  @brief  Append a string_view.
       *  @param __svt  An object convertible to string_view to be appended.
       *  @return  Reference to this string.
       */
      template<typename _Tp>
        _If_sv<_Tp, basic_string&>
        append(const _Tp& __svt)
        {
          __sv_type __sv = __svt;
          return this->append(__sv.data(), __sv.size());
        }

/**
       *  @brief  Append a range of characters from a string_view.
       *  @param __svt  An object convertible to string_view to be appended from.
       *  @param __pos The position in the string_view to append from.
       *  @param __n   The number of characters to append from the string_view.
       *  @return  Reference to this string.
       */
      template<typename _Tp>
        _If_sv<_Tp, basic_string&>
	append(const _Tp& __svt, size_type __pos, size_type __n = npos)
	{
	  __sv_type __sv = __svt;
	  return _M_append(__sv.data()
			   + __sv._M_check(__pos, "basic_string::append"),
			   __sv._M_limit(__pos, __n));
	}
#endif // C++17

/**
       *  @brief  Append a single character.
       *  @param __c  Character to append.
       */
      void
      push_back(_CharT __c)
      {
	const size_type __size = this->size();
	if (__size + 1 > this->capacity())
	  this->_M_mutate(__size, size_type(0), 0, size_type(1));
	traits_type::assign(this->_M_data()[__size], __c);
	this->_M_set_length(__size + 1);
      }

/**
       *  @brief  Set value to contents of another string.
       *  @param  __str  Source string to use.
       *  @return  Reference to this string.
       */
      basic_string&
      assign(const basic_string& __str)
      {
	this->_M_assign(__str);
	return *this;
      }

#if __cplusplus >= 201103L
      /**
       *  @brief  Set value to contents of another string.
       *  @param  __str  Source string to use.
       *  @return  Reference to this string.
       *
       *  This function sets this string to the exact contents of @a __str.
       *  @a __str is a valid, but unspecified string.
       */
      basic_string&
      assign(basic_string&& __str)
      noexcept(_Alloc_traits::_S_nothrow_move())
      {
	// _GLIBCXX_RESOLVE_LIB_DEFECTS
	// 2063. Contradictory requirements for string move assignment
	return *this = std::move(__str);
      }
#endif // C++11

/**
       *  @brief  Set value to a substring of a string.
       *  @param __str  The string to use.
       *  @param __pos  Index of the first character of str.
       *  @param __n  Number of characters to use.
       *  @return  Reference to this string.
       *  @throw  std::out_of_range if @a pos is not a valid index.
       *
       *  This function sets this string to the substring of @a __str
       *  consisting of @a __n characters at @a __pos.  If @a __n is
       *  is larger than the number of available characters in @a
       *  __str, the remainder of @a __str is used.
       */
      basic_string&
      assign(const basic_string& __str, size_type __pos, size_type __n = npos)
      { return _M_replace(size_type(0), this->size(), __str._M_data()
			  + __str._M_check(__pos, "basic_string::assign"),
			  __str._M_limit(__pos, __n)); }

/**
       *  @brief  Set value to a C substring.
       *  @param __s  The C string to use.
       *  @param __n  Number of characters to use.
       *  @return  Reference to this string.
       *
       *  This function sets the value of this string to the first @a __n
       *  characters of @a __s.  If @a __n is is larger than the number of
       *  available characters in @a __s, the remainder of @a __s is used.
       */
      basic_string&
      assign(const _CharT* __s, size_type __n)
      {
	__glibcxx_requires_string_len(__s, __n);
	return _M_replace(size_type(0), this->size(), __s, __n);
      }

/**
       *  @brief  Set value to contents of a C string.
       *  @param __s  The C string to use.
       *  @return  Reference to this string.
       *
       *  This function sets the value of this string to the value of @a __s.
       *  The data is copied, so there is no dependence on @a __s once the
       *  function returns.
       */
      basic_string&
      assign(const _CharT* __s)
      {
	__glibcxx_requires_string(__s);
	return _M_replace(size_type(0), this->size(), __s,
			  traits_type::length(__s));
      }

/**
       *  @brief  Set value to multiple characters.
       *  @param __n  Length of the resulting string.
       *  @param __c  The character to use.
       *  @return  Reference to this string.
       *
       *  This function sets the value of this string to @a __n copies of
       *  character @a __c.
       */
      basic_string&
      assign(size_type __n, _CharT __c)
      { return _M_replace_aux(size_type(0), this->size(), __n, __c); }

/**
       *  @brief  Set value to a range of characters.
       *  @param __first  Iterator referencing the first character to append.
       *  @param __last  Iterator marking the end of the range.
       *  @return  Reference to this string.
       *
       *  Sets value of string to characters in the range [__first,__last).
      */
#if __cplusplus >= 201103L
      template<class _InputIterator,
	       typename = std::_RequireInputIter<_InputIterator>>
#else
      template<class _InputIterator>
#endif
        basic_string&
        assign(_InputIterator __first, _InputIterator __last)
        { return this->replace(begin(), end(), __first, __last); }

#if __cplusplus >= 201103L
      /**
       *  @brief  Set value to an initializer_list of characters.
       *  @param __l  The initializer_list of characters to assign.
       *  @return  Reference to this string.
       */
      basic_string&
      assign(initializer_list<_CharT> __l)
      { return this->assign(__l.begin(), __l.size()); }
#endif // C++11

#if __cplusplus > 201402L
      /**
       *  @brief  Set value from a string_view.
       *  @param __svt  The source object convertible to string_view.
       *  @return  Reference to this string.
       */
      template<typename _Tp>
	_If_sv<_Tp, basic_string&>
	assign(const _Tp& __svt)
	{
	  __sv_type __sv = __svt;
	  return this->assign(__sv.data(), __sv.size());
	}

/**
       *  @brief  Set value from a range of characters in a string_view.
       *  @param __svt  The source object convertible to string_view.
       *  @param __pos  The position in the string_view to assign from.
       *  @param __n  The number of characters to assign.
       *  @return  Reference to this string.
       */
      template<typename _Tp>
	_If_sv<_Tp, basic_string&>
	assign(const _Tp& __svt, size_type __pos, size_type __n = npos)
	{
	  __sv_type __sv = __svt;
	  return _M_replace(size_type(0), this->size(), __sv.data()
			    + __sv._M_check(__pos, "basic_string::assign"),
			    __sv._M_limit(__pos, __n));
	}
#endif // C++17

#if __cplusplus >= 201103L
      /**
       *  @brief  Insert multiple characters.
       *  @param __p  Const_iterator referencing location in string to
       *              insert at.
       *  @param __n  Number of characters to insert
       *  @param __c  The character to insert.
       *  @return  Iterator referencing the first inserted char.
       *  @throw  std::length_error  If new length exceeds @c max_size().
       *
       *  Inserts @a __n copies of character @a __c starting at the
       *  position referenced by iterator @a __p.  If adding
       *  characters causes the length to exceed max_size(),
       *  length_error is thrown.  The value of the string doesn't
       *  change if an error is thrown.
      */
      iterator
      insert(const_iterator __p, size_type __n, _CharT __c)
      {
	_GLIBCXX_DEBUG_PEDASSERT(__p >= begin() && __p <= end());
	const size_type __pos = __p - begin();
	this->replace(__p, __p, __n, __c);
	return iterator(this->_M_data() + __pos);
      }
#else
      /**
       *  @brief  Insert multiple characters.
       *  @param __p  Iterator referencing location in string to insert at.
       *  @param __n  Number of characters to insert
       *  @param __c  The character to insert.
       *  @throw  std::length_error  If new length exceeds @c max_size().
       *
       *  Inserts @a __n copies of character @a __c starting at the
       *  position referenced by iterator @a __p.  If adding
       *  characters causes the length to exceed max_size(),
       *  length_error is thrown.  The value of the string doesn't
       *  change if an error is thrown.
      */
      void
      insert(iterator __p, size_type __n, _CharT __c)
      {	this->replace(__p, __p, __n, __c);  }
#endif

#if __cplusplus >= 201103L
      /**
       *  @brief  Insert a range of characters.
       *  @param __p  Const_iterator referencing location in string to
       *              insert at.
       *  @param __beg  Start of range.
       *  @param __end  End of range.
       *  @return  Iterator referencing the first inserted char.
       *  @throw  std::length_error  If new length exceeds @c max_size().
       *
       *  Inserts characters in range [beg,end).  If adding characters
       *  causes the length to exceed max_size(), length_error is
       *  thrown.  The value of the string doesn't change if an error
       *  is thrown.
      */
      template<class _InputIterator,
	       typename = std::_RequireInputIter<_InputIterator>>
	iterator
        insert(const_iterator __p, _InputIterator __beg, _InputIterator __end)
        {
	  _GLIBCXX_DEBUG_PEDASSERT(__p >= begin() && __p <= end());
	  const size_type __pos = __p - begin();
	  this->replace(__p, __p, __beg, __end);
	  return iterator(this->_M_data() + __pos);
	}
#else
      /**
       *  @brief  Insert a range of characters.
       *  @param __p  Iterator referencing location in string to insert at.
       *  @param __beg  Start of range.
       *  @param __end  End of range.
       *  @throw  std::length_error  If new length exceeds @c max_size().
       *
       *  Inserts characters in range [__beg,__end).  If adding
       *  characters causes the length to exceed max_size(),
       *  length_error is thrown.  The value of the string doesn't
       *  change if an error is thrown.
      */
      template<class _InputIterator>
        void
        insert(iterator __p, _InputIterator __beg, _InputIterator __end)
        { this->replace(__p, __p, __beg, __end); }
#endif

#if __cplusplus >= 201103L
      /**
       *  @brief  Insert an initializer_list of characters.
       *  @param __p  Iterator referencing location in string to insert at.
       *  @param __l  The initializer_list of characters to insert.
       *  @throw  std::length_error  If new length exceeds @c max_size().
       */
      void
      insert(iterator __p, initializer_list<_CharT> __l)
      {
	_GLIBCXX_DEBUG_PEDASSERT(__p >= begin() && __p <= end());
	this->insert(__p - begin(), __l.begin(), __l.size());
      }
#endif // C++11

/**
       *  @brief  Insert value of a string.
       *  @param __pos1  Iterator referencing location in string to insert at.
       *  @param __str  The string to insert.
       *  @return  Reference to this string.
       *  @throw  std::length_error  If new length exceeds @c max_size().
       *
       *  Inserts value of @a __str starting at @a __pos1.  If adding
       *  characters causes the length to exceed max_size(),
       *  length_error is thrown.  The value of the string doesn't
       *  change if an error is thrown.
      */
      basic_string&
      insert(size_type __pos1, const basic_string& __str)
      { return this->replace(__pos1, size_type(0),
			     __str._M_data(), __str.size()); }

/**
       *  @brief  Insert a substring.
       *  @param __pos1  Iterator referencing location in string to insert at.
       *  @param __str  The string to insert.
       *  @param __pos2  Start of characters in str to insert.
       *  @param __n  Number of characters to insert.
       *  @return  Reference to this string.
       *  @throw  std::length_error  If new length exceeds @c max_size().
       *  @throw  std::out_of_range  If @a pos1 > size() or
       *  @a __pos2 > @a str.size().
       *
       *  Starting at @a pos1, insert @a __n character of @a __str
       *  beginning with @a __pos2.  If adding characters causes the
       *  length to exceed max_size(), length_error is thrown.  If @a
       *  __pos1 is beyond the end of this string or @a __pos2 is
       *  beyond the end of @a __str, out_of_range is thrown.  The
       *  value of the string doesn't change if an error is thrown.
      */
      basic_string&
      insert(size_type __pos1, const basic_string& __str,
	     size_type __pos2, size_type __n = npos)
      { return this->replace(__pos1, size_type(0), __str._M_data()
			     + __str._M_check(__pos2, "basic_string::insert"),
			     __str._M_limit(__pos2, __n)); }

/**
       *  @brief  Insert a C substring.
       *  @param __pos  Iterator referencing location in string to insert at.
       *  @param __s  The C string to insert.
       *  @param __n  The number of characters to insert.
       *  @return  Reference to this string.
       *  @throw  std::length_error  If new length exceeds @c max_size().
       *  @throw  std::out_of_range  If @a __pos is beyond the end of this
       *  string.
       *
       *  Inserts the first @a __n characters of @a __s starting at @a
       *  __pos.  If adding characters causes the length to exceed
       *  max_size(), length_error is thrown.  If @a __pos is beyond
       *  end(), out_of_range is thrown.  The value of the string
       *  doesn't change if an error is thrown.
      */
      basic_string&
      insert(size_type __pos, const _CharT* __s, size_type __n)
      { return this->replace(__pos, size_type(0), __s, __n); }

/**
       *  @brief  Insert a C string.
       *  @param __pos  Iterator referencing location in string to insert at.
       *  @param __s  The C string to insert.
       *  @return  Reference to this string.
       *  @throw  std::length_error  If new length exceeds @c max_size().
       *  @throw  std::out_of_range  If @a pos is beyond the end of this
       *  string.
       *
       *  Inserts the first @a n characters of @a __s starting at @a __pos.  If
       *  adding characters causes the length to exceed max_size(),
       *  length_error is thrown.  If @a __pos is beyond end(), out_of_range is
       *  thrown.  The value of the string doesn't change if an error is
       *  thrown.
      */
      basic_string&
      insert(size_type __pos, const _CharT* __s)
      {
	__glibcxx_requires_string(__s);
	return this->replace(__pos, size_type(0), __s,
			     traits_type::length(__s));
      }

/**
       *  @brief  Insert multiple characters.
       *  @param __pos  Index in string to insert at.
       *  @param __n  Number of characters to insert
       *  @param __c  The character to insert.
       *  @return  Reference to this string.
       *  @throw  std::length_error  If new length exceeds @c max_size().
       *  @throw  std::out_of_range  If @a __pos is beyond the end of this
       *  string.
       *
       *  Inserts @a __n copies of character @a __c starting at index
       *  @a __pos.  If adding characters causes the length to exceed
       *  max_size(), length_error is thrown.  If @a __pos > length(),
       *  out_of_range is thrown.  The value of the string doesn't
       *  change if an error is thrown.
      */
      basic_string&
      insert(size_type __pos, size_type __n, _CharT __c)
      { return _M_replace_aux(_M_check(__pos, "basic_string::insert"),
			      size_type(0), __n, __c); }

/**
       *  @brief  Insert one character.
       *  @param __p  Iterator referencing position in string to insert at.
       *  @param __c  The character to insert.
       *  @return  Iterator referencing newly inserted char.
       *  @throw  std::length_error  If new length exceeds @c max_size().
       *
       *  Inserts character @a __c at position referenced by @a __p.
       *  If adding character causes the length to exceed max_size(),
       *  length_error is thrown.  If @a __p is beyond end of string,
       *  out_of_range is thrown.  The value of the string doesn't
       *  change if an error is thrown.
      */
      iterator
      insert(__const_iterator __p, _CharT __c)
      {
	_GLIBCXX_DEBUG_PEDASSERT(__p >= begin() && __p <= end());
	const size_type __pos = __p - begin();
	_M_replace_aux(__pos, size_type(0), size_type(1), __c);
	return iterator(_M_data() + __pos);
      }

#if __cplusplus > 201402L
      /**
       *  @brief  Insert a string_view.
       *  @param __pos  Iterator referencing position in string to insert at.
       *  @param __svt  The object convertible to string_view to insert.
       *  @return  Reference to this string.
      */
      template<typename _Tp>
	_If_sv<_Tp, basic_string&>
	insert(size_type __pos, const _Tp& __svt)
	{
	  __sv_type __sv = __svt;
	  return this->insert(__pos, __sv.data(), __sv.size());
	}

/**
       *  @brief  Insert a string_view.
       *  @param __pos  Iterator referencing position in string to insert at.
       *  @param __svt  The object convertible to string_view to insert from.
       *  @param __pos  Iterator referencing position in string_view to insert
       *  from.
       *  @param __n    The number of characters to insert.
       *  @return  Reference to this string.
      */
      template<typename _Tp>
	_If_sv<_Tp, basic_string&>
	insert(size_type __pos1, const _Tp& __svt,
	       size_type __pos2, size_type __n = npos)
	{
	  __sv_type __sv = __svt;
	  return this->replace(__pos1, size_type(0), __sv.data()
			       + __sv._M_check(__pos2, "basic_string::insert"),
			       __sv._M_limit(__pos2, __n));
	}
#endif // C++17

/**
       *  @brief  Remove characters.
       *  @param __pos  Index of first character to remove (default 0).
       *  @param __n  Number of characters to remove (default remainder).
       *  @return  Reference to this string.
       *  @throw  std::out_of_range  If @a pos is beyond the end of this
       *  string.
       *
       *  Removes @a __n characters from this string starting at @a
       *  __pos.  The length of the string is reduced by @a __n.  If
       *  there are < @a __n characters to remove, the remainder of
       *  the string is truncated.  If @a __p is beyond end of string,
       *  out_of_range is thrown.  The value of the string doesn't
       *  change if an error is thrown.
      */
      basic_string&
      erase(size_type __pos = 0, size_type __n = npos)
      {
	_M_check(__pos, "basic_string::erase");
	if (__n == npos)
	  this->_M_set_length(__pos);
	else if (__n != 0)
	  this->_M_erase(__pos, _M_limit(__pos, __n));
	return *this;
      }

/**
       *  @brief  Remove one character.
       *  @param __position  Iterator referencing the character to remove.
       *  @return  iterator referencing same location after removal.
       *
       *  Removes the character at @a __position from this string. The value
       *  of the string doesn't change if an error is thrown.
      */
      iterator
      erase(__const_iterator __position)
      {
	_GLIBCXX_DEBUG_PEDASSERT(__position >= begin()
				 && __position < end());
	const size_type __pos = __position - begin();
	this->_M_erase(__pos, size_type(1));
	return iterator(_M_data() + __pos);
      }

/**
       *  @brief  Remove a range of characters.
       *  @param __first  Iterator referencing the first character to remove.
       *  @param __last  Iterator referencing the end of the range.
       *  @return  Iterator referencing location of first after removal.
       *
       *  Removes the characters in the range [first,last) from this string.
       *  The value of the string doesn't change if an error is thrown.
      */
      iterator
      erase(__const_iterator __first, __const_iterator __last)
      {
	_GLIBCXX_DEBUG_PEDASSERT(__first >= begin() && __first <= __last
				 && __last <= end());
        const size_type __pos = __first - begin();
	if (__last == end())
	  this->_M_set_length(__pos);
	else
	  this->_M_erase(__pos, __last - __first);
	return iterator(this->_M_data() + __pos);
      }

#if __cplusplus >= 201103L
      /**
       *  @brief  Remove the last character.
       *
       *  The string must be non-empty.
       */
      void
      pop_back() noexcept
      {
	__glibcxx_assert(!empty());
	_M_erase(size() - 1, 1);
      }
#endif // C++11

/**
       *  @brief  Replace characters with value from another string.
       *  @param __pos  Index of first character to replace.
       *  @param __n  Number of characters to be replaced.
       *  @param __str  String to insert.
       *  @return  Reference to this string.
       *  @throw  std::out_of_range  If @a pos is beyond the end of this
       *  string.
       *  @throw  std::length_error  If new length exceeds @c max_size().
       *
       *  Removes the characters in the range [__pos,__pos+__n) from
       *  this string.  In place, the value of @a __str is inserted.
       *  If @a __pos is beyond end of string, out_of_range is thrown.
       *  If the length of the result exceeds max_size(), length_error
       *  is thrown.  The value of the string doesn't change if an
       *  error is thrown.
      */
      basic_string&
      replace(size_type __pos, size_type __n, const basic_string& __str)
      { return this->replace(__pos, __n, __str._M_data(), __str.size()); }

/**
       *  @brief  Replace characters with value from another string.
       *  @param __pos1  Index of first character to replace.
       *  @param __n1  Number of characters to be replaced.
       *  @param __str  String to insert.
       *  @param __pos2  Index of first character of str to use.
       *  @param __n2  Number of characters from str to use.
       *  @return  Reference to this string.
       *  @throw  std::out_of_range  If @a __pos1 > size() or @a __pos2 >
       *  __str.size().
       *  @throw  std::length_error  If new length exceeds @c max_size().
       *
       *  Removes the characters in the range [__pos1,__pos1 + n) from this
       *  string.  In place, the value of @a __str is inserted.  If @a __pos is
       *  beyond end of string, out_of_range is thrown.  If the length of the
       *  result exceeds max_size(), length_error is thrown.  The value of the
       *  string doesn't change if an error is thrown.
      */
      basic_string&
      replace(size_type __pos1, size_type __n1, const basic_string& __str,
	      size_type __pos2, size_type __n2 = npos)
      { return this->replace(__pos1, __n1, __str._M_data()
			     + __str._M_check(__pos2, "basic_string::replace"),
			     __str._M_limit(__pos2, __n2)); }

/**
       *  @brief  Replace characters with value of a C substring.
       *  @param __pos  Index of first character to replace.
       *  @param __n1  Number of characters to be replaced.
       *  @param __s  C string to insert.
       *  @param __n2  Number of characters from @a s to use.
       *  @return  Reference to this string.
       *  @throw  std::out_of_range  If @a pos1 > size().
       *  @throw  std::length_error  If new length exceeds @c max_size().
       *
       *  Removes the characters in the range [__pos,__pos + __n1)
       *  from this string.  In place, the first @a __n2 characters of
       *  @a __s are inserted, or all of @a __s if @a __n2 is too large.  If
       *  @a __pos is beyond end of string, out_of_range is thrown.  If
       *  the length of result exceeds max_size(), length_error is
       *  thrown.  The value of the string doesn't change if an error
       *  is thrown.
      */
      basic_string&
      replace(size_type __pos, size_type __n1, const _CharT* __s,
	      size_type __n2)
      {
	__glibcxx_requires_string_len(__s, __n2);
	return _M_replace(_M_check(__pos, "basic_string::replace"),
			  _M_limit(__pos, __n1), __s, __n2);
      }

/**
       *  @brief  Replace characters with value of a C string.
       *  @param __pos  Index of first character to replace.
       *  @param __n1  Number of characters to be replaced.
       *  @param __s  C string to insert.
       *  @return  Reference to this string.
       *  @throw  std::out_of_range  If @a pos > size().
       *  @throw  std::length_error  If new length exceeds @c max_size().
       *
       *  Removes the characters in the range [__pos,__pos + __n1)
       *  from this string.  In place, the characters of @a __s are
       *  inserted.  If @a __pos is beyond end of string, out_of_range
       *  is thrown.  If the length of result exceeds max_size(),
       *  length_error is thrown.  The value of the string doesn't
       *  change if an error is thrown.
      */
      basic_string&
      replace(size_type __pos, size_type __n1, const _CharT* __s)
      {
	__glibcxx_requires_string(__s);
	return this->replace(__pos, __n1, __s, traits_type::length(__s));
      }

/**
       *  @brief  Replace characters with multiple characters.
       *  @param __pos  Index of first character to replace.
       *  @param __n1  Number of characters to be replaced.
       *  @param __n2  Number of characters to insert.
       *  @param __c  Character to insert.
       *  @return  Reference to this string.
       *  @throw  std::out_of_range  If @a __pos > size().
       *  @throw  std::length_error  If new length exceeds @c max_size().
       *
       *  Removes the characters in the range [pos,pos + n1) from this
       *  string.  In place, @a __n2 copies of @a __c are inserted.
       *  If @a __pos is beyond end of string, out_of_range is thrown.
       *  If the length of result exceeds max_size(), length_error is
       *  thrown.  The value of the string doesn't change if an error
       *  is thrown.
      */
      basic_string&
      replace(size_type __pos, size_type __n1, size_type __n2, _CharT __c)
      { return _M_replace_aux(_M_check(__pos, "basic_string::replace"),
			      _M_limit(__pos, __n1), __n2, __c); }

/**
       *  @brief  Replace range of characters with string.
       *  @param __i1  Iterator referencing start of range to replace.
       *  @param __i2  Iterator referencing end of range to replace.
       *  @param __str  String value to insert.
       *  @return  Reference to this string.
       *  @throw  std::length_error  If new length exceeds @c max_size().
       *
       *  Removes the characters in the range [__i1,__i2).  In place,
       *  the value of @a __str is inserted.  If the length of result
       *  exceeds max_size(), length_error is thrown.  The value of
       *  the string doesn't change if an error is thrown.
      */
      basic_string&
      replace(__const_iterator __i1, __const_iterator __i2,
	      const basic_string& __str)
      { return this->replace(__i1, __i2, __str._M_data(), __str.size()); }

/**
       *  @brief  Replace range of characters with C substring.
       *  @param __i1  Iterator referencing start of range to replace.
       *  @param __i2  Iterator referencing end of range to replace.
       *  @param __s  C string value to insert.
       *  @param __n  Number of characters from s to insert.
       *  @return  Reference to this string.
       *  @throw  std::length_error  If new length exceeds @c max_size().
       *
       *  Removes the characters in the range [__i1,__i2).  In place,
       *  the first @a __n characters of @a __s are inserted.  If the
       *  length of result exceeds max_size(), length_error is thrown.
       *  The value of the string doesn't change if an error is
       *  thrown.
      */
      basic_string&
      replace(__const_iterator __i1, __const_iterator __i2,
	      const _CharT* __s, size_type __n)
      {
	_GLIBCXX_DEBUG_PEDASSERT(begin() <= __i1 && __i1 <= __i2
				 && __i2 <= end());
	return this->replace(__i1 - begin(), __i2 - __i1, __s, __n);
      }

/**
       *  @brief  Replace range of characters with C string.
       *  @param __i1  Iterator referencing start of range to replace.
       *  @param __i2  Iterator referencing end of range to replace.
       *  @param __s  C string value to insert.
       *  @return  Reference to this string.
       *  @throw  std::length_error  If new length exceeds @c max_size().
       *
       *  Removes the characters in the range [__i1,__i2).  In place,
       *  the characters of @a __s are inserted.  If the length of
       *  result exceeds max_size(), length_error is thrown.  The
       *  value of the string doesn't change if an error is thrown.
      */
      basic_string&
      replace(__const_iterator __i1, __const_iterator __i2, const _CharT* __s)
      {
	__glibcxx_requires_string(__s);
	return this->replace(__i1, __i2, __s, traits_type::length(__s));
      }

/**
       *  @brief  Replace range of characters with multiple characters
       *  @param __i1  Iterator referencing start of range to replace.
       *  @param __i2  Iterator referencing end of range to replace.
       *  @param __n  Number of characters to insert.
       *  @param __c  Character to insert.
       *  @return  Reference to this string.
       *  @throw  std::length_error  If new length exceeds @c max_size().
       *
       *  Removes the characters in the range [__i1,__i2).  In place,
       *  @a __n copies of @a __c are inserted.  If the length of
       *  result exceeds max_size(), length_error is thrown.  The
       *  value of the string doesn't change if an error is thrown.
      */
      basic_string&
      replace(__const_iterator __i1, __const_iterator __i2, size_type __n,
	      _CharT __c)
      {
	_GLIBCXX_DEBUG_PEDASSERT(begin() <= __i1 && __i1 <= __i2
				 && __i2 <= end());
	return _M_replace_aux(__i1 - begin(), __i2 - __i1, __n, __c);
      }

/**
       *  @brief  Replace range of characters with range.
       *  @param __i1  Iterator referencing start of range to replace.
       *  @param __i2  Iterator referencing end of range to replace.
       *  @param __k1  Iterator referencing start of range to insert.
       *  @param __k2  Iterator referencing end of range to insert.
       *  @return  Reference to this string.
       *  @throw  std::length_error  If new length exceeds @c max_size().
       *
       *  Removes the characters in the range [__i1,__i2).  In place,
       *  characters in the range [__k1,__k2) are inserted.  If the
       *  length of result exceeds max_size(), length_error is thrown.
       *  The value of the string doesn't change if an error is
       *  thrown.
      */
#if __cplusplus >= 201103L
      template<class _InputIterator,
	       typename = std::_RequireInputIter<_InputIterator>>
        basic_string&
        replace(const_iterator __i1, const_iterator __i2,
		_InputIterator __k1, _InputIterator __k2)
        {
	  _GLIBCXX_DEBUG_PEDASSERT(begin() <= __i1 && __i1 <= __i2
				   && __i2 <= end());
	  __glibcxx_requires_valid_range(__k1, __k2);
	  return this->_M_replace_dispatch(__i1, __i2, __k1, __k2,
					   std::__false_type());
	}
#else
      template<class _InputIterator>
#ifdef _GLIBCXX_DISAMBIGUATE_REPLACE_INST
        typename __enable_if_not_native_iterator<_InputIterator>::__type
#else
        basic_string&
#endif
        replace(iterator __i1, iterator __i2,
		_InputIterator __k1, _InputIterator __k2)
        {
	  _GLIBCXX_DEBUG_PEDASSERT(begin() <= __i1 && __i1 <= __i2
				   && __i2 <= end());
	  __glibcxx_requires_valid_range(__k1, __k2);
	  typedef typename std::__is_integer<_InputIterator>::__type _Integral;
	  return _M_replace_dispatch(__i1, __i2, __k1, __k2, _Integral());
	}
#endif

// Specializations for the common case of pointer and iterator:
      // useful to avoid the overhead of temporary buffering in _M_replace.
      basic_string&
      replace(__const_iterator __i1, __const_iterator __i2,
	      _CharT* __k1, _CharT* __k2)
      {
	_GLIBCXX_DEBUG_PEDASSERT(begin() <= __i1 && __i1 <= __i2
				 && __i2 <= end());
	__glibcxx_requires_valid_range(__k1, __k2);
	return this->replace(__i1 - begin(), __i2 - __i1,
			     __k1, __k2 - __k1);
      }

basic_string&
      replace(__const_iterator __i1, __const_iterator __i2,
	      const _CharT* __k1, const _CharT* __k2)
      {
	_GLIBCXX_DEBUG_PEDASSERT(begin() <= __i1 && __i1 <= __i2
				 && __i2 <= end());
	__glibcxx_requires_valid_range(__k1, __k2);
	return this->replace(__i1 - begin(), __i2 - __i1,
			     __k1, __k2 - __k1);
      }

basic_string&
      replace(__const_iterator __i1, __const_iterator __i2,
	      iterator __k1, iterator __k2)
      {
	_GLIBCXX_DEBUG_PEDASSERT(begin() <= __i1 && __i1 <= __i2
				 && __i2 <= end());
	__glibcxx_requires_valid_range(__k1, __k2);
	return this->replace(__i1 - begin(), __i2 - __i1,
			     __k1.base(), __k2 - __k1);
      }

basic_string&
      replace(__const_iterator __i1, __const_iterator __i2,
	      const_iterator __k1, const_iterator __k2)
      {
	_GLIBCXX_DEBUG_PEDASSERT(begin() <= __i1 && __i1 <= __i2
				 && __i2 <= end());
	__glibcxx_requires_valid_range(__k1, __k2);
	return this->replace(__i1 - begin(), __i2 - __i1,
			     __k1.base(), __k2 - __k1);
      }

#if __cplusplus >= 201103L
      /**
       *  @brief  Replace range of characters with initializer_list.
       *  @param __i1  Iterator referencing start of range to replace.
       *  @param __i2  Iterator referencing end of range to replace.
       *  @param __l  The initializer_list of characters to insert.
       *  @return  Reference to this string.
       *  @throw  std::length_error  If new length exceeds @c max_size().
       *
       *  Removes the characters in the range [__i1,__i2).  In place,
       *  characters in the range [__k1,__k2) are inserted.  If the
       *  length of result exceeds max_size(), length_error is thrown.
       *  The value of the string doesn't change if an error is
       *  thrown.
      */
      basic_string& replace(const_iterator __i1, const_iterator __i2,
			    initializer_list<_CharT> __l)
      { return this->replace(__i1, __i2, __l.begin(), __l.size()); }
#endif // C++11

#if __cplusplus > 201402L
      /**
       *  @brief  Replace range of characters with string_view.
       *  @param __pos  The position to replace at.
       *  @param __n    The number of characters to replace.
       *  @param __svt  The object convertible to string_view to insert.
       *  @return  Reference to this string.
      */
      template<typename _Tp>
	_If_sv<_Tp, basic_string&>
	replace(size_type __pos, size_type __n, const _Tp& __svt)
	{
	  __sv_type __sv = __svt;
	  return this->replace(__pos, __n, __sv.data(), __sv.size());
	}

/**
       *  @brief  Replace range of characters with string_view.
       *  @param __pos1  The position to replace at.
       *  @param __n1    The number of characters to replace.
       *  @param __svt   The object convertible to string_view to insert from.
       *  @param __pos2  The position in the string_view to insert from.
       *  @param __n2    The number of characters to insert.
       *  @return  Reference to this string.
      */
      template<typename _Tp>
	_If_sv<_Tp, basic_string&>
	replace(size_type __pos1, size_type __n1, const _Tp& __svt,
		size_type __pos2, size_type __n2 = npos)
	{
	  __sv_type __sv = __svt;
	  return this->replace(__pos1, __n1, __sv.data()
			       + __sv._M_check(__pos2, "basic_string::replace"),
			       __sv._M_limit(__pos2, __n2));
	}

/**
       *  @brief  Replace range of characters with string_view.
       *  @param __i1    An iterator referencing the start position
          to replace at.
       *  @param __i2    An iterator referencing the end position
          for the replace.
       *  @param __svt   The object convertible to string_view to insert from.
       *  @return  Reference to this string.
      */
      template<typename _Tp>
	_If_sv<_Tp, basic_string&>
	replace(const_iterator __i1, const_iterator __i2, const _Tp& __svt)
	{
	  __sv_type __sv = __svt;
	  return this->replace(__i1 - begin(), __i2 - __i1, __sv);
	}
#endif // C++17

private:
      template<class _Integer>
	basic_string&
	_M_replace_dispatch(const_iterator __i1, const_iterator __i2,
			    _Integer __n, _Integer __val, __true_type)
        { return _M_replace_aux(__i1 - begin(), __i2 - __i1, __n, __val); }

template<class _InputIterator>
	basic_string&
	_M_replace_dispatch(const_iterator __i1, const_iterator __i2,
			    _InputIterator __k1, _InputIterator __k2,
			    __false_type);

basic_string&
      _M_replace_aux(size_type __pos1, size_type __n1, size_type __n2,
		     _CharT __c);

basic_string&
      _M_replace(size_type __pos, size_type __len1, const _CharT* __s,
		 const size_type __len2);

basic_string&
      _M_append(const _CharT* __s, size_type __n);

public:

/**
       *  @brief  Copy substring into C string.
       *  @param __s  C string to copy value into.
       *  @param __n  Number of characters to copy.
       *  @param __pos  Index of first character to copy.
       *  @return  Number of characters actually copied
       *  @throw  std::out_of_range  If __pos > size().
       *
       *  Copies up to @a __n characters starting at @a __pos into the
       *  C string @a __s.  If @a __pos is %greater than size(),
       *  out_of_range is thrown.
      */
      size_type
      copy(_CharT* __s, size_type __n, size_type __pos = 0) const;

/**
       *  @brief  Swap contents with another string.
       *  @param __s  String to swap with.
       *
       *  Exchanges the contents of this string with that of @a __s in constant
       *  time.
      */
      void
      swap(basic_string& __s) _GLIBCXX_NOEXCEPT;

// String operations:
      /**
       *  @brief  Return const pointer to null-terminated contents.
       *
       *  This is a handle to internal data.  Do not modify or dire things may
       *  happen.
      */
      const _CharT*
      c_str() const _GLIBCXX_NOEXCEPT
      { return _M_data(); }

/**
       *  @brief  Return const pointer to contents.
       *
       *  This is a pointer to internal data.  It is undefined to modify
       *  the contents through the returned pointer. To get a pointer that
       *  allows modifying the contents use @c &str[0] instead,
       *  (or in C++17 the non-const @c str.data() overload).
      */
      const _CharT*
      data() const _GLIBCXX_NOEXCEPT
      { return _M_data(); }

#if __cplusplus > 201402L
      /**
       *  @brief  Return non-const pointer to contents.
       *
       *  This is a pointer to the character sequence held by the string.
       *  Modifying the characters in the sequence is allowed.
      */
      _CharT*
      data() noexcept
      { return _M_data(); }
#endif

/**
       *  @brief  Return copy of allocator used to construct this string.
      */
      allocator_type
      get_allocator() const _GLIBCXX_NOEXCEPT
      { return _M_get_allocator(); }

/**
       *  @brief  Find position of a C substring.
       *  @param __s  C string to locate.
       *  @param __pos  Index of character to search from.
       *  @param __n  Number of characters from @a s to search for.
       *  @return  Index of start of first occurrence.
       *
       *  Starting from @a __pos, searches forward for the first @a
       *  __n characters in @a __s within this string.  If found,
       *  returns the index where it begins.  If not found, returns
       *  npos.
      */
      size_type
      find(const _CharT* __s, size_type __pos, size_type __n) const
      _GLIBCXX_NOEXCEPT;

/**
       *  @brief  Find position of a string.
       *  @param __str  String to locate.
       *  @param __pos  Index of character to search from (default 0).
       *  @return  Index of start of first occurrence.
       *
       *  Starting from @a __pos, searches forward for value of @a __str within
       *  this string.  If found, returns the index where it begins.  If not
       *  found, returns npos.
      */
      size_type
      find(const basic_string& __str, size_type __pos = 0) const
      _GLIBCXX_NOEXCEPT
      { return this->find(__str.data(), __pos, __str.size()); }

#if __cplusplus > 201402L
      /**
       *  @brief  Find position of a string_view.
       *  @param __svt  The object convertible to string_view to locate.
       *  @param __pos  Index of character to search from (default 0).
       *  @return  Index of start of first occurrence.
      */
      template<typename _Tp>
	_If_sv<_Tp, size_type>
	find(const _Tp& __svt, size_type __pos = 0) const
	noexcept(is_same<_Tp, __sv_type>::value)
	{
	  __sv_type __sv = __svt;
	  return this->find(__sv.data(), __pos, __sv.size());
	}
#endif // C++17

/**
       *  @brief  Find position of a C string.
       *  @param __s  C string to locate.
       *  @param __pos  Index of character to search from (default 0).
       *  @return  Index of start of first occurrence.
       *
       *  Starting from @a __pos, searches forward for the value of @a
       *  __s within this string.  If found, returns the index where
       *  it begins.  If not found, returns npos.
      */
      size_type
      find(const _CharT* __s, size_type __pos = 0) const _GLIBCXX_NOEXCEPT
      {
	__glibcxx_requires_string(__s);
	return this->find(__s, __pos, traits_type::length(__s));
      }

/**
       *  @brief  Find position of a character.
       *  @param __c  Character to locate.
       *  @param __pos  Index of character to search from (default 0).
       *  @return  Index of first occurrence.
       *
       *  Starting from @a __pos, searches forward for @a __c within
       *  this string.  If found, returns the index where it was
       *  found.  If not found, returns npos.
      */
      size_type
      find(_CharT __c, size_type __pos = 0) const _GLIBCXX_NOEXCEPT;

/**
       *  @brief  Find last position of a string.
       *  @param __str  String to locate.
       *  @param __pos  Index of character to search back from (default end).
       *  @return  Index of start of last occurrence.
       *
       *  Starting from @a __pos, searches backward for value of @a
       *  __str within this string.  If found, returns the index where
       *  it begins.  If not found, returns npos.
      */
      size_type
      rfind(const basic_string& __str, size_type __pos = npos) const
      _GLIBCXX_NOEXCEPT
      { return this->rfind(__str.data(), __pos, __str.size()); }

#if __cplusplus > 201402L
      /**
       *  @brief  Find last position of a string_view.
       *  @param __svt  The object convertible to string_view to locate.
       *  @param __pos  Index of character to search back from (default end).
       *  @return  Index of start of last occurrence.
      */
      template<typename _Tp>
	_If_sv<_Tp, size_type>
	rfind(const _Tp& __svt, size_type __pos = npos) const
	noexcept(is_same<_Tp, __sv_type>::value)
	{
	  __sv_type __sv = __svt;
	  return this->rfind(__sv.data(), __pos, __sv.size());
	}
#endif // C++17

/**
       *  @brief  Find last position of a C substring.
       *  @param __s  C string to locate.
       *  @param __pos  Index of character to search back from.
       *  @param __n  Number of characters from s to search for.
       *  @return  Index of start of last occurrence.
       *
       *  Starting from @a __pos, searches backward for the first @a
       *  __n characters in @a __s within this string.  If found,
       *  returns the index where it begins.  If not found, returns
       *  npos.
      */
      size_type
      rfind(const _CharT* __s, size_type __pos, size_type __n) const
      _GLIBCXX_NOEXCEPT;

/**
       *  @brief  Find last position of a C string.
       *  @param __s  C string to locate.
       *  @param __pos  Index of character to start search at (default end).
       *  @return  Index of start of  last occurrence.
       *
       *  Starting from @a __pos, searches backward for the value of
       *  @a __s within this string.  If found, returns the index
       *  where it begins.  If not found, returns npos.
      */
      size_type
      rfind(const _CharT* __s, size_type __pos = npos) const
      {
	__glibcxx_requires_string(__s);
	return this->rfind(__s, __pos, traits_type::length(__s));
      }

/**
       *  @brief  Find last position of a character.
       *  @param __c  Character to locate.
       *  @param __pos  Index of character to search back from (default end).
       *  @return  Index of last occurrence.
       *
       *  Starting from @a __pos, searches backward for @a __c within
       *  this string.  If found, returns the index where it was
       *  found.  If not found, returns npos.
      */
      size_type
      rfind(_CharT __c, size_type __pos = npos) const _GLIBCXX_NOEXCEPT;

/**
       *  @brief  Find position of a character of string.
       *  @param __str  String containing characters to locate.
       *  @param __pos  Index of character to search from (default 0).
       *  @return  Index of first occurrence.
       *
       *  Starting from @a __pos, searches forward for one of the
       *  characters of @a __str within this string.  If found,
       *  returns the index where it was found.  If not found, returns
       *  npos.
      */
      size_type
      find_first_of(const basic_string& __str, size_type __pos = 0) const
      _GLIBCXX_NOEXCEPT
      { return this->find_first_of(__str.data(), __pos, __str.size()); }

#if __cplusplus > 201402L
      /**
       *  @brief  Find position of a character of a string_view.
       *  @param __svt  An object convertible to string_view containing
       *                characters to locate.
       *  @param __pos  Index of character to search from (default 0).
       *  @return  Index of first occurrence.
      */
      template<typename _Tp>
	_If_sv<_Tp, size_type>
	find_first_of(const _Tp& __svt, size_type __pos = 0) const
	noexcept(is_same<_Tp, __sv_type>::value)
	{
	  __sv_type __sv = __svt;
	  return this->find_first_of(__sv.data(), __pos, __sv.size());
	}
#endif // C++17

/**
       *  @brief  Find position of a character of C substring.
       *  @param __s  String containing characters to locate.
       *  @param __pos  Index of character to search from.
       *  @param __n  Number of characters from s to search for.
       *  @return  Index of first occurrence.
       *
       *  Starting from @a __pos, searches forward for one of the
       *  first @a __n characters of @a __s within this string.  If
       *  found, returns the index where it was found.  If not found,
       *  returns npos.
      */
      size_type
      find_first_of(const _CharT* __s, size_type __pos, size_type __n) const
      _GLIBCXX_NOEXCEPT;

/**
       *  @brief  Find position of a character of C string.
       *  @param __s  String containing characters to locate.
       *  @param __pos  Index of character to search from (default 0).
       *  @return  Index of first occurrence.
       *
       *  Starting from @a __pos, searches forward for one of the
       *  characters of @a __s within this string.  If found, returns
       *  the index where it was found.  If not found, returns npos.
      */
      size_type
      find_first_of(const _CharT* __s, size_type __pos = 0) const
      _GLIBCXX_NOEXCEPT
      {
	__glibcxx_requires_string(__s);
	return this->find_first_of(__s, __pos, traits_type::length(__s));
      }

/**
       *  @brief  Find position of a character.
       *  @param __c  Character to locate.
       *  @param __pos  Index of character to search from (default 0).
       *  @return  Index of first occurrence.
       *
       *  Starting from @a __pos, searches forward for the character
       *  @a __c within this string.  If found, returns the index
       *  where it was found.  If not found, returns npos.
       *
       *  Note: equivalent to find(__c, __pos).
      */
      size_type
      find_first_of(_CharT __c, size_type __pos = 0) const _GLIBCXX_NOEXCEPT
      { return this->find(__c, __pos); }

/**
       *  @brief  Find last position of a character of string.
       *  @param __str  String containing characters to locate.
       *  @param __pos  Index of character to search back from (default end).
       *  @return  Index of last occurrence.
       *
       *  Starting from @a __pos, searches backward for one of the
       *  characters of @a __str within this string.  If found,
       *  returns the index where it was found.  If not found, returns
       *  npos.
      */
      size_type
      find_last_of(const basic_string& __str, size_type __pos = npos) const
      _GLIBCXX_NOEXCEPT
      { return this->find_last_of(__str.data(), __pos, __str.size()); }

#if __cplusplus > 201402L
      /**
       *  @brief  Find last position of a character of string.
       *  @param __svt  An object convertible to string_view containing
       *                characters to locate.
       *  @param __pos  Index of character to search back from (default end).
       *  @return  Index of last occurrence.
      */
      template<typename _Tp>
	_If_sv<_Tp, size_type>
	find_last_of(const _Tp& __svt, size_type __pos = npos) const
	noexcept(is_same<_Tp, __sv_type>::value)
	{
	  __sv_type __sv = __svt;
	  return this->find_last_of(__sv.data(), __pos, __sv.size());
	}
#endif // C++17

/**
       *  @brief  Find last position of a character of C substring.
       *  @param __s  C string containing characters to locate.
       *  @param __pos  Index of character to search back from.
       *  @param __n  Number of characters from s to search for.
       *  @return  Index of last occurrence.
       *
       *  Starting from @a __pos, searches backward for one of the
       *  first @a __n characters of @a __s within this string.  If
       *  found, returns the index where it was found.  If not found,
       *  returns npos.
      */
      size_type
      find_last_of(const _CharT* __s, size_type __pos, size_type __n) const
      _GLIBCXX_NOEXCEPT;

/**
       *  @brief  Find last position of a character of C string.
       *  @param __s  C string containing characters to locate.
       *  @param __pos  Index of character to search back from (default end).
       *  @return  Index of last occurrence.
       *
       *  Starting from @a __pos, searches backward for one of the
       *  characters of @a __s within this string.  If found, returns
       *  the index where it was found.  If not found, returns npos.
      */
      size_type
      find_last_of(const _CharT* __s, size_type __pos = npos) const
      _GLIBCXX_NOEXCEPT
      {
	__glibcxx_requires_string(__s);
	return this->find_last_of(__s, __pos, traits_type::length(__s));
      }

/**
       *  @brief  Find last position of a character.
       *  @param __c  Character to locate.
       *  @param __pos  Index of character to search back from (default end).
       *  @return  Index of last occurrence.
       *
       *  Starting from @a __pos, searches backward for @a __c within
       *  this string.  If found, returns the index where it was
       *  found.  If not found, returns npos.
       *
       *  Note: equivalent to rfind(__c, __pos).
      */
      size_type
      find_last_of(_CharT __c, size_type __pos = npos) const _GLIBCXX_NOEXCEPT
      { return this->rfind(__c, __pos); }

/**
       *  @brief  Find position of a character not in string.
       *  @param __str  String containing characters to avoid.
       *  @param __pos  Index of character to search from (default 0).
       *  @return  Index of first occurrence.
       *
       *  Starting from @a __pos, searches forward for a character not contained
       *  in @a __str within this string.  If found, returns the index where it
       *  was found.  If not found, returns npos.
      */
      size_type
      find_first_not_of(const basic_string& __str, size_type __pos = 0) const
      _GLIBCXX_NOEXCEPT
      { return this->find_first_not_of(__str.data(), __pos, __str.size()); }

#if __cplusplus > 201402L
      /**
       *  @brief  Find position of a character not in a string_view.
       *  @param __svt  A object convertible to string_view containing
       *                characters to avoid.
       *  @param __pos  Index of character to search from (default 0).
       *  @return  Index of first occurrence.
       */
      template<typename _Tp>
	_If_sv<_Tp, size_type>
	find_first_not_of(const _Tp& __svt, size_type __pos = 0) const
	noexcept(is_same<_Tp, __sv_type>::value)
	{
	  __sv_type __sv = __svt;
	  return this->find_first_not_of(__sv.data(), __pos, __sv.size());
	}
#endif // C++17

/**
       *  @brief  Find position of a character not in C substring.
       *  @param __s  C string containing characters to avoid.
       *  @param __pos  Index of character to search from.
       *  @param __n  Number of characters from __s to consider.
       *  @return  Index of first occurrence.
       *
       *  Starting from @a __pos, searches forward for a character not
       *  contained in the first @a __n characters of @a __s within
       *  this string.  If found, returns the index where it was
       *  found.  If not found, returns npos.
      */
      size_type
      find_first_not_of(const _CharT* __s, size_type __pos,
			size_type __n) const _GLIBCXX_NOEXCEPT;

/**
       *  @brief  Find position of a character not in C string.
       *  @param __s  C string containing characters to avoid.
       *  @param __pos  Index of character to search from (default 0).
       *  @return  Index of first occurrence.
       *
       *  Starting from @a __pos, searches forward for a character not
       *  contained in @a __s within this string.  If found, returns
       *  the index where it was found.  If not found, returns npos.
      */
      size_type
      find_first_not_of(const _CharT* __s, size_type __pos = 0) const
      _GLIBCXX_NOEXCEPT
      {
	__glibcxx_requires_string(__s);
	return this->find_first_not_of(__s, __pos, traits_type::length(__s));
      }

/**
       *  @brief  Find position of a different character.
       *  @param __c  Character to avoid.
       *  @param __pos  Index of character to search from (default 0).
       *  @return  Index of first occurrence.
       *
       *  Starting from @a __pos, searches forward for a character
       *  other than @a __c within this string.  If found, returns the
       *  index where it was found.  If not found, returns npos.
      */
      size_type
      find_first_not_of(_CharT __c, size_type __pos = 0) const
      _GLIBCXX_NOEXCEPT;

/**
       *  @brief  Find last position of a character not in string.
       *  @param __str  String containing characters to avoid.
       *  @param __pos  Index of character to search back from (default end).
       *  @return  Index of last occurrence.
       *
       *  Starting from @a __pos, searches backward for a character
       *  not contained in @a __str within this string.  If found,
       *  returns the index where it was found.  If not found, returns
       *  npos.
      */
      size_type
      find_last_not_of(const basic_string& __str, size_type __pos = npos) const
      _GLIBCXX_NOEXCEPT
      { return this->find_last_not_of(__str.data(), __pos, __str.size()); }

#if __cplusplus > 201402L
      /**
       *  @brief  Find last position of a character not in a string_view.
       *  @param __svt  An object convertible to string_view containing
       *                characters to avoid.
       *  @param __pos  Index of character to search back from (default end).
       *  @return  Index of last occurrence.
       */
      template<typename _Tp>
	_If_sv<_Tp, size_type>
	find_last_not_of(const _Tp& __svt, size_type __pos = npos) const
	noexcept(is_same<_Tp, __sv_type>::value)
	{
	  __sv_type __sv = __svt;
	  return this->find_last_not_of(__sv.data(), __pos, __sv.size());
	}
#endif // C++17

/**
       *  @brief  Find last position of a character not in C substring.
       *  @param __s  C string containing characters to avoid.
       *  @param __pos  Index of character to search back from.
       *  @param __n  Number of characters from s to consider.
       *  @return  Index of last occurrence.
       *
       *  Starting from @a __pos, searches backward for a character not
       *  contained in the first @a __n characters of @a __s within this string.
       *  If found, returns the index where it was found.  If not found,
       *  returns npos.
      */
      size_type
      find_last_not_of(const _CharT* __s, size_type __pos,
		       size_type __n) const _GLIBCXX_NOEXCEPT;
      /**
       *  @brief  Find last position of a character not in C string.
       *  @param __s  C string containing characters to avoid.
       *  @param __pos  Index of character to search back from (default end).
       *  @return  Index of last occurrence.
       *
       *  Starting from @a __pos, searches backward for a character
       *  not contained in @a __s within this string.  If found,
       *  returns the index where it was found.  If not found, returns
       *  npos.
      */
      size_type
      find_last_not_of(const _CharT* __s, size_type __pos = npos) const
      _GLIBCXX_NOEXCEPT
      {
	__glibcxx_requires_string(__s);
	return this->find_last_not_of(__s, __pos, traits_type::length(__s));
      }

/**
       *  @brief  Find last position of a different character.
       *  @param __c  Character to avoid.
       *  @param __pos  Index of character to search back from (default end).
       *  @return  Index of last occurrence.
       *
       *  Starting from @a __pos, searches backward for a character other than
       *  @a __c within this string.  If found, returns the index where it was
       *  found.  If not found, returns npos.
      */
      size_type
      find_last_not_of(_CharT __c, size_type __pos = npos) const
      _GLIBCXX_NOEXCEPT;

/**
       *  @brief  Get a substring.
       *  @param __pos  Index of first character (default 0).
       *  @param __n  Number of characters in substring (default remainder).
       *  @return  The new string.
       *  @throw  std::out_of_range  If __pos > size().
       *
       *  Construct and return a new string using the @a __n
       *  characters starting at @a __pos.  If the string is too
       *  short, use the remainder of the characters.  If @a __pos is
       *  beyond the end of the string, out_of_range is thrown.
      */
      basic_string
      substr(size_type __pos = 0, size_type __n = npos) const
      { return basic_string(*this,
			    _M_check(__pos, "basic_string::substr"), __n); }

/**
       *  @brief  Compare to a string.
       *  @param __str  String to compare against.
       *  @return  Integer < 0, 0, or > 0.
       *
       *  Returns an integer < 0 if this string is ordered before @a
       *  __str, 0 if their values are equivalent, or > 0 if this
       *  string is ordered after @a __str.  Determines the effective
       *  length rlen of the strings to compare as the smallest of
       *  size() and str.size().  The function then compares the two
       *  strings by calling traits::compare(data(), str.data(),rlen).
       *  If the result of the comparison is nonzero returns it,
       *  otherwise the shorter one is ordered first.
      */
      int
      compare(const basic_string& __str) const
      {
	const size_type __size = this->size();
	const size_type __osize = __str.size();
	const size_type __len = std::min(__size, __osize);

int __r = traits_type::compare(_M_data(), __str.data(), __len);
	if (!__r)
	  __r = _S_compare(__size, __osize);
	return __r;
      }

#if __cplusplus > 201402L
      /**
       *  @brief  Compare to a string_view.
       *  @param __svt An object convertible to string_view to compare against.
       *  @return  Integer < 0, 0, or > 0.
       */
      template<typename _Tp>
	_If_sv<_Tp, int>
	compare(const _Tp& __svt) const
	noexcept(is_same<_Tp, __sv_type>::value)
	{
	  __sv_type __sv = __svt;
	  const size_type __size = this->size();
	  const size_type __osize = __sv.size();
	  const size_type __len = std::min(__size, __osize);

int __r = traits_type::compare(_M_data(), __sv.data(), __len);
	  if (!__r)
	    __r = _S_compare(__size, __osize);
	  return __r;
	}

/**
       *  @brief  Compare to a string_view.
       *  @param __pos  A position in the string to start comparing from.
       *  @param __n  The number of characters to compare.
       *  @param __svt  An object convertible to string_view to compare
       *                against.
       *  @return  Integer < 0, 0, or > 0.
       */
      template<typename _Tp>
	_If_sv<_Tp, int>
	compare(size_type __pos, size_type __n, const _Tp& __svt) const
	noexcept(is_same<_Tp, __sv_type>::value)
	{
	  __sv_type __sv = __svt;
	  return __sv_type(*this).substr(__pos, __n).compare(__sv);
	}

/**
       *  @brief  Compare to a string_view.
       *  @param __pos1  A position in the string to start comparing from.
       *  @param __n1  The number of characters to compare.
       *  @param __svt  An object convertible to string_view to compare
       *                against.
       *  @param __pos2  A position in the string_view to start comparing from.
       *  @param __n2  The number of characters to compare.
       *  @return  Integer < 0, 0, or > 0.
       */
      template<typename _Tp>
	_If_sv<_Tp, int>
	compare(size_type __pos1, size_type __n1, const _Tp& __svt,
		size_type __pos2, size_type __n2 = npos) const
	noexcept(is_same<_Tp, __sv_type>::value)
	{
	  __sv_type __sv = __svt;
	  return __sv_type(*this)
	    .substr(__pos1, __n1).compare(__sv.substr(__pos2, __n2));
	}
#endif // C++17

/**
       *  @brief  Compare substring to a string.
       *  @param __pos  Index of first character of substring.
       *  @param __n  Number of characters in substring.
       *  @param __str  String to compare against.
       *  @return  Integer < 0, 0, or > 0.
       *
       *  Form the substring of this string from the @a __n characters
       *  starting at @a __pos.  Returns an integer < 0 if the
       *  substring is ordered before @a __str, 0 if their values are
       *  equivalent, or > 0 if the substring is ordered after @a
       *  __str.  Determines the effective length rlen of the strings
       *  to compare as the smallest of the length of the substring
       *  and @a __str.size().  The function then compares the two
       *  strings by calling
       *  traits::compare(substring.data(),str.data(),rlen).  If the
       *  result of the comparison is nonzero returns it, otherwise
       *  the shorter one is ordered first.
      */
      int
      compare(size_type __pos, size_type __n, const basic_string& __str) const;

/**
       *  @brief  Compare substring to a substring.
       *  @param __pos1  Index of first character of substring.
       *  @param __n1  Number of characters in substring.
       *  @param __str  String to compare against.
       *  @param __pos2  Index of first character of substring of str.
       *  @param __n2  Number of characters in substring of str.
       *  @return  Integer < 0, 0, or > 0.
       *
       *  Form the substring of this string from the @a __n1
       *  characters starting at @a __pos1.  Form the substring of @a
       *  __str from the @a __n2 characters starting at @a __pos2.
       *  Returns an integer < 0 if this substring is ordered before
       *  the substring of @a __str, 0 if their values are equivalent,
       *  or > 0 if this substring is ordered after the substring of
       *  @a __str.  Determines the effective length rlen of the
       *  strings to compare as the smallest of the lengths of the
       *  substrings.  The function then compares the two strings by
       *  calling
       *  traits::compare(substring.data(),str.substr(pos2,n2).data(),rlen).
       *  If the result of the comparison is nonzero returns it,
       *  otherwise the shorter one is ordered first.
      */
      int
      compare(size_type __pos1, size_type __n1, const basic_string& __str,
	      size_type __pos2, size_type __n2 = npos) const;

/**
       *  @brief  Compare to a C string.
       *  @param __s  C string to compare against.
       *  @return  Integer < 0, 0, or > 0.
       *
       *  Returns an integer < 0 if this string is ordered before @a __s, 0 if
       *  their values are equivalent, or > 0 if this string is ordered after
       *  @a __s.  Determines the effective length rlen of the strings to
       *  compare as the smallest of size() and the length of a string
       *  constructed from @a __s.  The function then compares the two strings
       *  by calling traits::compare(data(),s,rlen).  If the result of the
       *  comparison is nonzero returns it, otherwise the shorter one is
       *  ordered first.
      */
      int
      compare(const _CharT* __s) const _GLIBCXX_NOEXCEPT;

// _GLIBCXX_RESOLVE_LIB_DEFECTS
      // 5 String::compare specification questionable
      /**
       *  @brief  Compare substring to a C string.
       *  @param __pos  Index of first character of substring.
       *  @param __n1  Number of characters in substring.
       *  @param __s  C string to compare against.
       *  @return  Integer < 0, 0, or > 0.
       *
       *  Form the substring of this string from the @a __n1
       *  characters starting at @a pos.  Returns an integer < 0 if
       *  the substring is ordered before @a __s, 0 if their values
       *  are equivalent, or > 0 if the substring is ordered after @a
       *  __s.  Determines the effective length rlen of the strings to
       *  compare as the smallest of the length of the substring and
       *  the length of a string constructed from @a __s.  The
       *  function then compares the two string by calling
       *  traits::compare(substring.data(),__s,rlen).  If the result of
       *  the comparison is nonzero returns it, otherwise the shorter
       *  one is ordered first.
      */
      int
      compare(size_type __pos, size_type __n1, const _CharT* __s) const;

/**
       *  @brief  Compare substring against a character %array.
       *  @param __pos  Index of first character of substring.
       *  @param __n1  Number of characters in substring.
       *  @param __s  character %array to compare against.
       *  @param __n2  Number of characters of s.
       *  @return  Integer < 0, 0, or > 0.
       *
       *  Form the substring of this string from the @a __n1
       *  characters starting at @a __pos.  Form a string from the
       *  first @a __n2 characters of @a __s.  Returns an integer < 0
       *  if this substring is ordered before the string from @a __s,
       *  0 if their values are equivalent, or > 0 if this substring
       *  is ordered after the string from @a __s.  Determines the
       *  effective length rlen of the strings to compare as the
       *  smallest of the length of the substring and @a __n2.  The
       *  function then compares the two strings by calling
       *  traits::compare(substring.data(),s,rlen).  If the result of
       *  the comparison is nonzero returns it, otherwise the shorter
       *  one is ordered first.
       *
       *  NB: s must have at least n2 characters, &apos;\\0&apos; has
       *  no special meaning.
      */
      int
      compare(size_type __pos, size_type __n1, const _CharT* __s,
	      size_type __n2) const;

// Allow basic_stringbuf::__xfer_bufptrs to call _M_length:
      template<typename, typename, typename> friend class basic_stringbuf;
    };
_GLIBCXX_END_NAMESPACE_CXX11
#else  // !_GLIBCXX_USE_CXX11_ABI
  // Reference-counted COW string implentation

/**
   *  @class basic_string basic_string.h <string>
   *  @brief  Managing sequences of characters and character-like objects.
   *
   *  @ingroup strings
   *  @ingroup sequences
   *
   *  @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.
   *
   *  @doctodo
   *
   *
   *  Documentation?  What's that?
   *  Nathan Myers <ncm@cantrip.org>.
   *
   *  A string looks like this:
   *
   *  @code
   *                                        [_Rep]
   *                                        _M_length
   *   [basic_string<char_type>]            _M_capacity
   *   _M_dataplus                          _M_refcount
   *   _M_p ---------------->               unnamed array of char_type
   *  @endcode
   *
   *  Where the _M_p points to the first character in the string, and
   *  you cast it to a pointer-to-_Rep and subtract 1 to get a
   *  pointer to the header.
   *
   *  This approach has the enormous advantage that a string object
   *  requires only one allocation.  All the ugliness is confined
   *  within a single %pair of inline functions, which each compile to
   *  a single @a add instruction: _Rep::_M_data(), and
   *  string::_M_rep(); and the allocation function which gets a
   *  block of raw bytes and with room enough and constructs a _Rep
   *  object at the front.
   *
   *  The reason you want _M_data pointing to the character %array and
   *  not the _Rep is so that the debugger can see the string
   *  contents. (Probably we should add a non-inline member to get
   *  the _Rep for the debugger to use, so users can check the actual
   *  string length.)
   *
   *  Note that the _Rep object is a POD so that you can have a
   *  static <em>empty string</em> _Rep object already @a constructed before
   *  static constructors have run.  The reference-count encoding is
   *  chosen so that a 0 indicates one reference, so you never try to
   *  destroy the empty-string _Rep object.
   *
   *  All but the last paragraph is considered pretty conventional
   *  for a C++ string implementation.
  */
  // 21.3  Template class basic_string
  template<typename _CharT, typename _Traits, typename _Alloc>
    class basic_string
    {
      typedef typename _Alloc::template rebind<_CharT>::other _CharT_alloc_type;

// Types:
    public:
      typedef _Traits					    traits_type;
      typedef typename _Traits::char_type		    value_type;
      typedef _Alloc					    allocator_type;
      typedef typename _CharT_alloc_type::size_type	    size_type;
      typedef typename _CharT_alloc_type::difference_type   difference_type;
      typedef typename _CharT_alloc_type::reference	    reference;
      typedef typename _CharT_alloc_type::const_reference   const_reference;
      typedef typename _CharT_alloc_type::pointer	    pointer;
      typedef typename _CharT_alloc_type::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;

private:
      // _Rep: string representation
      //   Invariants:
      //   1. String really contains _M_length + 1 characters: due to 21.3.4
      //      must be kept null-terminated.
      //   2. _M_capacity >= _M_length
      //      Allocated memory is always (_M_capacity + 1) * sizeof(_CharT).
      //   3. _M_refcount has three states:
      //      -1: leaked, one reference, no ref-copies allowed, non-const.
      //       0: one reference, non-const.
      //     n>0: n + 1 references, operations require a lock, const.
      //   4. All fields==0 is an empty string, given the extra storage
      //      beyond-the-end for a null terminator; thus, the shared
      //      empty string representation needs no constructor.

struct _Rep_base
      {
	size_type		_M_length;
	size_type		_M_capacity;
	_Atomic_word		_M_refcount;
      };

struct _Rep : _Rep_base
      {
	// Types:
	typedef typename _Alloc::template rebind<char>::other _Raw_bytes_alloc;

// (Public) Data members:

// The maximum number of individual char_type elements of an
	// individual string is determined by _S_max_size. This is the
	// value that will be returned by max_size().  (Whereas npos
	// is the maximum number of bytes the allocator can allocate.)
	// If one was to divvy up the theoretical largest size string,
	// with a terminating character and m _CharT elements, it'd
	// look like this:
	// npos = sizeof(_Rep) + (m * sizeof(_CharT)) + sizeof(_CharT)
	// Solving for m:
	// m = ((npos - sizeof(_Rep))/sizeof(CharT)) - 1
	// In addition, this implementation quarters this amount.
	static const size_type	_S_max_size;
	static const _CharT	_S_terminal;

// The following storage is init'd to 0 by the linker, resulting
        // (carefully) in an empty string with one reference.
        static size_type _S_empty_rep_storage[];

static _Rep&
        _S_empty_rep() _GLIBCXX_NOEXCEPT
        { 
	  // NB: Mild hack to avoid strict-aliasing warnings.  Note that
	  // _S_empty_rep_storage is never modified and the punning should
	  // be reasonably safe in this case.
	  void* __p = reinterpret_cast<void*>(&_S_empty_rep_storage);
	  return *reinterpret_cast<_Rep*>(__p);
	}

bool
	_M_is_leaked() const _GLIBCXX_NOEXCEPT
        {
#if defined(__GTHREADS)
          // _M_refcount is mutated concurrently by _M_refcopy/_M_dispose,
          // so we need to use an atomic load. However, _M_is_leaked
          // predicate does not change concurrently (i.e. the string is either
          // leaked or not), so a relaxed load is enough.
          return __atomic_load_n(&this->_M_refcount, __ATOMIC_RELAXED) < 0;
#else
          return this->_M_refcount < 0;
#endif
        }

bool
	_M_is_shared() const _GLIBCXX_NOEXCEPT
	{
#if defined(__GTHREADS)
          // _M_refcount is mutated concurrently by _M_refcopy/_M_dispose,
          // so we need to use an atomic load. Another thread can drop last
          // but one reference concurrently with this check, so we need this
          // load to be acquire to synchronize with release fetch_and_add in
          // _M_dispose.
          return __atomic_load_n(&this->_M_refcount, __ATOMIC_ACQUIRE) > 0;
#else
          return this->_M_refcount > 0;
#endif
        }

void
	_M_set_leaked() _GLIBCXX_NOEXCEPT
        { this->_M_refcount = -1; }

void
	_M_set_sharable() _GLIBCXX_NOEXCEPT
        { this->_M_refcount = 0; }

void
	_M_set_length_and_sharable(size_type __n) _GLIBCXX_NOEXCEPT
	{
#if _GLIBCXX_FULLY_DYNAMIC_STRING == 0
	  if (__builtin_expect(this != &_S_empty_rep(), false))
#endif
	    {
	      this->_M_set_sharable();  // One reference.
	      this->_M_length = __n;
	      traits_type::assign(this->_M_refdata()[__n], _S_terminal);
	      // grrr. (per 21.3.4)
	      // You cannot leave those LWG people alone for a second.
	    }
	}

_CharT*
	_M_refdata() throw()
	{ return reinterpret_cast<_CharT*>(this + 1); }

_CharT*
	_M_grab(const _Alloc& __alloc1, const _Alloc& __alloc2)
	{
	  return (!_M_is_leaked() && __alloc1 == __alloc2)
	          ? _M_refcopy() : _M_clone(__alloc1);
	}

// Create & Destroy
	static _Rep*
	_S_create(size_type, size_type, const _Alloc&);

void
	_M_dispose(const _Alloc& __a) _GLIBCXX_NOEXCEPT
	{
#if _GLIBCXX_FULLY_DYNAMIC_STRING == 0
	  if (__builtin_expect(this != &_S_empty_rep(), false))
#endif
	    {
	      // Be race-detector-friendly.  For more info see bits/c++config.
	      _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&this->_M_refcount);
              // Decrement of _M_refcount is acq_rel, because:
              // - all but last decrements need to release to synchronize with
              //   the last decrement that will delete the object.
              // - the last decrement needs to acquire to synchronize with
              //   all the previous decrements.
              // - last but one decrement needs to release to synchronize with
              //   the acquire load in _M_is_shared that will conclude that
              //   the object is not shared anymore.
	      if (__gnu_cxx::__exchange_and_add_dispatch(&this->_M_refcount,
							 -1) <= 0)
		{
		  _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&this->_M_refcount);
		  _M_destroy(__a);
		}
	    }
	}  // XXX MT

void
	_M_destroy(const _Alloc&) throw();

_CharT*
	_M_refcopy() throw()
	{
#if _GLIBCXX_FULLY_DYNAMIC_STRING == 0
	  if (__builtin_expect(this != &_S_empty_rep(), false))
#endif
            __gnu_cxx::__atomic_add_dispatch(&this->_M_refcount, 1);
	  return _M_refdata();
	}  // XXX MT

_CharT*
	_M_clone(const _Alloc&, size_type __res = 0);
      };

// Use empty-base optimization: http://www.cantrip.org/emptyopt.html
      struct _Alloc_hider : _Alloc
      {
	_Alloc_hider(_CharT* __dat, const _Alloc& __a) _GLIBCXX_NOEXCEPT
	: _Alloc(__a), _M_p(__dat) { }

_CharT* _M_p; // The actual data.
      };

public:
      // Data Members (public):
      // NB: This is an unsigned type, and thus represents the maximum
      // size that the allocator can hold.
      ///  Value returned by various member functions when they fail.
      static const size_type	npos = static_cast<size_type>(-1);

private:
      // Data Members (private):
      mutable _Alloc_hider	_M_dataplus;

_CharT*
      _M_data() const _GLIBCXX_NOEXCEPT
      { return  _M_dataplus._M_p; }

_CharT*
      _M_data(_CharT* __p) _GLIBCXX_NOEXCEPT
      { return (_M_dataplus._M_p = __p); }

_Rep*
      _M_rep() const _GLIBCXX_NOEXCEPT
      { return &((reinterpret_cast<_Rep*> (_M_data()))[-1]); }

// For the internal use we have functions similar to `begin'/`end'
      // but they do not call _M_leak.
      iterator
      _M_ibegin() const _GLIBCXX_NOEXCEPT
      { return iterator(_M_data()); }

iterator
      _M_iend() const _GLIBCXX_NOEXCEPT
      { return iterator(_M_data() + this->size()); }

void
      _M_leak()    // for use in begin() & non-const op[]
      {
	if (!_M_rep()->_M_is_leaked())
	  _M_leak_hard();
      }

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));
      }

// When __n = 1 way faster than the general multichar
      // traits_type::copy/move/assign.
      static void
      _M_copy(_CharT* __d, const _CharT* __s, size_type __n) _GLIBCXX_NOEXCEPT
      {
	if (__n == 1)
	  traits_type::assign(*__d, *__s);
	else
	  traits_type::copy(__d, __s, __n);
      }

static void
      _M_move(_CharT* __d, const _CharT* __s, size_type __n) _GLIBCXX_NOEXCEPT
      {
	if (__n == 1)
	  traits_type::assign(*__d, *__s);
	else
	  traits_type::move(__d, __s, __n);	  
      }

static void
      _M_assign(_CharT* __d, size_type __n, _CharT __c) _GLIBCXX_NOEXCEPT
      {
	if (__n == 1)
	  traits_type::assign(*__d, __c);
	else
	  traits_type::assign(__d, __n, __c);	  
      }

static void
      _S_copy_chars(_CharT* __p, iterator __k1, iterator __k2) _GLIBCXX_NOEXCEPT
      { _S_copy_chars(__p, __k1.base(), __k2.base()); }

static void
      _S_copy_chars(_CharT* __p, const_iterator __k1, const_iterator __k2)
      _GLIBCXX_NOEXCEPT
      { _S_copy_chars(__p, __k1.base(), __k2.base()); }

static void
      _S_copy_chars(_CharT* __p, _CharT* __k1, _CharT* __k2) _GLIBCXX_NOEXCEPT
      { _M_copy(__p, __k1, __k2 - __k1); }

static void
      _S_copy_chars(_CharT* __p, const _CharT* __k1, const _CharT* __k2)
      _GLIBCXX_NOEXCEPT
      { _M_copy(__p, __k1, __k2 - __k1); }

static int
      _S_compare(size_type __n1, size_type __n2) _GLIBCXX_NOEXCEPT
      {
	const difference_type __d = difference_type(__n1 - __n2);

void
      _M_mutate(size_type __pos, size_type __len1, size_type __len2);

void
      _M_leak_hard();

static _Rep&
      _S_empty_rep() _GLIBCXX_NOEXCEPT
      { return _Rep::_S_empty_rep(); }

#if __cplusplus > 201402L
      // A helper type for avoiding boiler-plate.
      typedef basic_string_view<_CharT, _Traits> __sv_type;

// Allows an implicit conversion to __sv_type.
      static __sv_type
      _S_to_string_view(__sv_type __svt) noexcept
      { return __svt; }

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.
       */
      basic_string()
#if _GLIBCXX_FULLY_DYNAMIC_STRING == 0
      : _M_dataplus(_S_empty_rep()._M_refdata(), _Alloc()) { }
#else
      : _M_dataplus(_S_construct(size_type(), _CharT(), _Alloc()), _Alloc()){ }
#endif

/**
       *  @brief  Construct an empty string using allocator @a a.
       */
      explicit
      basic_string(const _Alloc& __a);

// NB: per LWG issue 42, semantics different from IS:
      /**
       *  @brief  Construct string with copy of value of @a str.
       *  @param  __str  Source string.
       */
      basic_string(const basic_string& __str);

/**
       *  @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.
       */
      basic_string(const basic_string& __str, size_type __pos,
		   size_type __n);
      /**
       *  @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.
       */
      basic_string(const basic_string& __str, size_type __pos,
		   size_type __n, const _Alloc& __a);

/**
       *  @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, &apos;\\0&apos;
       *  has no special meaning.
       */
      basic_string(const _CharT* __s, size_type __n,
		   const _Alloc& __a = _Alloc());
      /**
       *  @brief  Construct string as copy of a C string.
       *  @param  __s  Source C string.
       *  @param  __a  Allocator to use (default is default allocator).
       */
      basic_string(const _CharT* __s, const _Alloc& __a = _Alloc());
      /**
       *  @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).
       */
      basic_string(size_type __n, _CharT __c, const _Alloc& __a = _Alloc());

#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.
       **/
      basic_string(basic_string&& __str)
#if _GLIBCXX_FULLY_DYNAMIC_STRING == 0
      noexcept // FIXME C++11: should always be noexcept.
#endif
      : _M_dataplus(__str._M_dataplus)
      {
#if _GLIBCXX_FULLY_DYNAMIC_STRING == 0
	__str._M_data(_S_empty_rep()._M_refdata());
#else
	__str._M_data(_S_construct(size_type(), _CharT(), get_allocator()));
#endif
      }

/**
       *  @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).
       */
      template<class _InputIterator>
        basic_string(_InputIterator __beg, _InputIterator __end,
		     const _Alloc& __a = _Alloc());

/**
       *  @brief  Destroy the string instance.
       */
      ~basic_string() _GLIBCXX_NOEXCEPT
      { _M_rep()->_M_dispose(this->get_allocator()); }

/**
       *  @brief  Assign the value of @a str to this string.
       *  @param  __str  Source string.
       */
      basic_string&
      operator=(const basic_string& __str) 
      { return this->assign(__str); }

/**
       *  @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.
       */
      basic_string&
      operator=(_CharT __c) 
      { 
	this->assign(1, __c); 
	return *this;
      }

#if __cplusplus > 201402L
      /**
       *  @brief  Set value to string constructed from a string_view.
       *  @param  __svt An object convertible to  string_view.
       */
      template<typename _Tp>
	_If_sv<_Tp, basic_string&>
	operator=(const _Tp& __svt)
	{ return this->assign(__svt); }

/**
       *  @brief  Convert to a string_view.
       *  @return A string_view.
       */
      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.  Unshares the string.
       */
      iterator
      begin() // FIXME C++11: should be noexcept.
      {
	_M_leak();
	return iterator(_M_data());
      }

/**
       *  Returns a read/write iterator that points one past the last
       *  character in the %string.  Unshares the string.
       */
      iterator
      end() // FIXME C++11: should be noexcept.
      {
	_M_leak();
	return 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.  Unshares the string.
       */
      reverse_iterator
      rbegin() // FIXME C++11: should be noexcept.
      { return reverse_iterator(this->end()); }

/**
       *  Returns a read/write reverse iterator that points to one before the
       *  first character in the %string.  Iteration is done in reverse
       *  element order.  Unshares the string.
       */
      reverse_iterator
      rend() // FIXME C++11: should be noexcept.
      { return reverse_iterator(this->begin()); }

/**
       *  Returns a read-only (constant) reverse iterator that points
       *  to the last character in the %string.  Iteration is done in
       *  reverse element order.
       */
      const_reverse_iterator
      crbegin() const noexcept
      { return const_reverse_iterator(this->end()); }

/**
       *  Returns a read-only (constant) reverse iterator that points
       *  to one before the first character in the %string.  Iteration
       *  is done in reverse element order.
       */
      const_reverse_iterator
      crend() const noexcept
      { return const_reverse_iterator(this->begin()); }
#endif

public:
      // Capacity:
      ///  Returns the number of characters in the string, not including any
      ///  null-termination.
      size_type
      size() const _GLIBCXX_NOEXCEPT
      { return _M_rep()->_M_length; }

///  Returns the number of characters in the string, not including any
      ///  null-termination.
      size_type
      length() const _GLIBCXX_NOEXCEPT
      { return _M_rep()->_M_length; }

///  Returns the size() of the largest possible %string.
      size_type
      max_size() const _GLIBCXX_NOEXCEPT
      { return _Rep::_S_max_size; }

#if __cplusplus >= 201103L
      ///  A non-binding request to reduce capacity() to size().
      void
      shrink_to_fit() _GLIBCXX_NOEXCEPT
      {
#if __cpp_exceptions
	if (capacity() > size())
	  {
	    try
	      { reserve(0); }
	    catch(...)
	      { }
	  }
#endif
      }
#endif

/**
       *  Returns the total number of characters that the %string can hold
       *  before needing to allocate more memory.
       */
      size_type
      capacity() const _GLIBCXX_NOEXCEPT
      { return _M_rep()->_M_capacity; }

/**
       *  Erases the string, making it empty.
       */
#if _GLIBCXX_FULLY_DYNAMIC_STRING == 0
      void
      clear() _GLIBCXX_NOEXCEPT
      {
	if (_M_rep()->_M_is_shared())
	  {
	    _M_rep()->_M_dispose(this->get_allocator());
	    _M_data(_S_empty_rep()._M_refdata());
	  }
	else
	  _M_rep()->_M_set_length_and_sharable(0);
      }
#else
      // PR 56166: this should not throw.
      void
      clear()
      { _M_mutate(0, this->size(), 0); }
#endif

/**
       *  Returns true if the %string is empty.  Equivalent to 
       *  <code>*this == ""</code>.
       */
      bool
      empty() const _GLIBCXX_NOEXCEPT
      { return this->size() == 0; }

/**
       *  @brief  Subscript access to the data contained in the %string.
       *  @param  __pos  The index of the character to access.
       *  @return  Read/write reference to the character.
       *
       *  This operator allows for easy, array-style, data access.
       *  Note that data access with this operator is unchecked and
       *  out_of_range lookups are not defined. (For checked lookups
       *  see at().)  Unshares the string.
       */
      reference
      operator[](size_type __pos)
      {
        // Allow pos == size() both in C++98 mode, as v3 extension,
	// and in C++11 mode.
	__glibcxx_assert(__pos <= size());
        // In pedantic mode be strict in C++98 mode.
	_GLIBCXX_DEBUG_PEDASSERT(__cplusplus >= 201103L || __pos < size());
	_M_leak();
	return _M_data()[__pos];
      }

/**
       *  @brief  Provides access to the data contained in the %string.
       *  @param __n The index of the character to access.
       *  @return  Read/write reference to the character.
       *  @throw  std::out_of_range  If @a n is an invalid index.
       *
       *  This function provides for safer data access.  The parameter is
       *  first checked that it is in the range of the string.  The function
       *  throws out_of_range if the check fails.  Success results in
       *  unsharing the string.
       */
      reference
      at(size_type __n)
      {
	if (__n >= size())
	  __throw_out_of_range_fmt(__N("basic_string::at: __n "
				       "(which is %zu) >= this->size() "
				       "(which is %zu)"),
				   __n, this->size());
	_M_leak();
	return _M_data()[__n];
      }

#if __cplusplus >= 201103L
      /**
       *  Returns a read/write reference to the data at the first
       *  element of the %string.
       */
      reference
      front()
      {
	__glibcxx_assert(!empty());
	return operator[](0);
      }

/**
       *  Returns a read/write reference to the data at the last
       *  element of the %string.
       */
      reference
      back()
      {
	__glibcxx_assert(!empty());
	return operator[](this->size() - 1);
      }

#if __cplusplus > 201402L
      /**
       *  @brief  Append a string_view.
       *  @param __svt The object convertible to string_view to be appended.
       *  @return  Reference to this string.
       */
      template<typename _Tp>
	_If_sv<_Tp, basic_string&>
	operator+=(const _Tp& __svt)
	{ return this->append(__svt); }
#endif // C++17

/**
       *  @brief  Append a string to this string.
       *  @param __str  The string to append.
       *  @return  Reference to this string.
       */
      basic_string&
      append(const basic_string& __str);

/**
       *  @brief  Append a C string.
       *  @param __s  The C string to append.
       *  @return  Reference to this string.
       */
      basic_string&
      append(const _CharT* __s)
      {
	__glibcxx_requires_string(__s);
	return this->append(__s, traits_type::length(__s));
      }

/**
       *  @brief  Append a range of characters.
       *  @param __first  Iterator referencing the first character to append.
       *  @param __last  Iterator marking the end of the range.
       *  @return  Reference to this string.
       *
       *  Appends characters in the range [__first,__last) to this string.
       */
      template<class _InputIterator>
        basic_string&
        append(_InputIterator __first, _InputIterator __last)
        { return this->replace(_M_iend(), _M_iend(), __first, __last); }

#if __cplusplus > 201402L
      /**
       *  @brief  Append a string_view.
       *  @param __svt The object convertible to string_view to be appended.
       *  @return  Reference to this string.
       */
      template<typename _Tp>
	_If_sv<_Tp, basic_string&>
	append(const _Tp& __svt)
	{
	  __sv_type __sv = __svt;
	  return this->append(__sv.data(), __sv.size());
	}

/**
       *  @brief  Append a range of characters from a string_view.
       *  @param __svt The object convertible to string_view to be appended
       *               from.
       *  @param __pos The position in the string_view to append from.
       *  @param __n   The number of characters to append from the string_view.
       *  @return  Reference to this string.
       */
      template<typename _Tp>
        _If_sv<_Tp, basic_string&>
	append(const _Tp& __svt, size_type __pos, size_type __n = npos)
	{
	  __sv_type __sv = __svt;
	  return append(__sv.data()
			+ __sv._M_check(__pos, "basic_string::append"),
			__sv._M_limit(__pos, __n));
	}
#endif // C++17

/**
       *  @brief  Append a single character.
       *  @param __c  Character to append.
       */
      void
      push_back(_CharT __c)
      { 
	const size_type __len = 1 + this->size();
	if (__len > this->capacity() || _M_rep()->_M_is_shared())
	  this->reserve(__len);
	traits_type::assign(_M_data()[this->size()], __c);
	_M_rep()->_M_set_length_and_sharable(__len);
      }

#if __cplusplus >= 201103L
      /**
       *  @brief  Set value to contents of another string.
       *  @param  __str  Source string to use.
       *  @return  Reference to this string.
       *
       *  This function sets this string to the exact contents of @a __str.
       *  @a __str is a valid, but unspecified string.
       */
      // PR 58265, this should be noexcept.
      basic_string&
      assign(basic_string&& __str)
      {
	this->swap(__str);
	return *this;
      }
#endif // C++11

/**
       *  @brief  Set value to a substring of a string.
       *  @param __str  The string to use.
       *  @param __pos  Index of the first character of str.
       *  @param __n  Number of characters to use.
       *  @return  Reference to this string.
       *  @throw  std::out_of_range if @a pos is not a valid index.
       *
       *  This function sets this string to the substring of @a __str
       *  consisting of @a __n characters at @a __pos.  If @a __n is
       *  is larger than the number of available characters in @a
       *  __str, the remainder of @a __str is used.
       */
      basic_string&
      assign(const basic_string& __str, size_type __pos, size_type __n = npos)
      { return this->assign(__str._M_data()
			    + __str._M_check(__pos, "basic_string::assign"),
			    __str._M_limit(__pos, __n)); }

/**
       *  @brief  Set value to contents of a C string.
       *  @param __s  The C string to use.
       *  @return  Reference to this string.
       *
       *  This function sets the value of this string to the value of @a __s.
       *  The data is copied, so there is no dependence on @a __s once the
       *  function returns.
       */
      basic_string&
      assign(const _CharT* __s)
      {
	__glibcxx_requires_string(__s);
	return this->assign(__s, traits_type::length(__s));
      }

/**
       *  @brief  Set value to a range of characters.
       *  @param __first  Iterator referencing the first character to append.
       *  @param __last  Iterator marking the end of the range.
       *  @return  Reference to this string.
       *
       *  Sets value of string to characters in the range [__first,__last).
      */
      template<class _InputIterator>
        basic_string&
        assign(_InputIterator __first, _InputIterator __last)
        { return this->replace(_M_ibegin(), _M_iend(), __first, __last); }

#if __cplusplus > 201402L
      /**
       *  @brief  Set value from a string_view.
       *  @param __svt The source object convertible to string_view.
       *  @return  Reference to this string.
       */
      template<typename _Tp>
	_If_sv<_Tp, basic_string&>
	assign(const _Tp& __svt)
	{
	  __sv_type __sv = __svt;
	  return this->assign(__sv.data(), __sv.size());
	}

/**
       *  @brief  Set value from a range of characters in a string_view.
       *  @param __svt  The source object convertible to string_view.
       *  @param __pos  The position in the string_view to assign from.
       *  @param __n  The number of characters to assign.
       *  @return  Reference to this string.
       */
      template<typename _Tp>
        _If_sv<_Tp, basic_string&>
        assign(const _Tp& __svt, size_type __pos, size_type __n = npos)
	{
	  __sv_type __sv = __svt;
	  return assign(__sv.data()
			+ __sv._M_check(__pos, "basic_string::assign"),
			__sv._M_limit(__pos, __n));
	}
#endif // C++17

/**
       *  @brief  Insert multiple characters.
       *  @param __p  Iterator referencing location in string to insert at.
       *  @param __n  Number of characters to insert
       *  @param __c  The character to insert.
       *  @throw  std::length_error  If new length exceeds @c max_size().
       *
       *  Inserts @a __n copies of character @a __c starting at the
       *  position referenced by iterator @a __p.  If adding
       *  characters causes the length to exceed max_size(),
       *  length_error is thrown.  The value of the string doesn't
       *  change if an error is thrown.
      */
      void
      insert(iterator __p, size_type __n, _CharT __c)
      {	this->replace(__p, __p, __n, __c);  }

/**
       *  @brief  Insert a range of characters.
       *  @param __p  Iterator referencing location in string to insert at.
       *  @param __beg  Start of range.
       *  @param __end  End of range.
       *  @throw  std::length_error  If new length exceeds @c max_size().
       *
       *  Inserts characters in range [__beg,__end).  If adding
       *  characters causes the length to exceed max_size(),
       *  length_error is thrown.  The value of the string doesn't
       *  change if an error is thrown.
      */
      template<class _InputIterator>
        void
        insert(iterator __p, _InputIterator __beg, _InputIterator __end)
        { this->replace(__p, __p, __beg, __end); }

#if __cplusplus >= 201103L
      /**
       *  @brief  Insert an initializer_list of characters.
       *  @param __p  Iterator referencing location in string to insert at.
       *  @param __l  The initializer_list of characters to insert.
       *  @throw  std::length_error  If new length exceeds @c max_size().
       */
      void
      insert(iterator __p, initializer_list<_CharT> __l)
      {
	_GLIBCXX_DEBUG_PEDASSERT(__p >= _M_ibegin() && __p <= _M_iend());
	this->insert(__p - _M_ibegin(), __l.begin(), __l.size());
      }
#endif // C++11

/**
       *  @brief  Insert value of a string.
       *  @param __pos1  Iterator referencing location in string to insert at.
       *  @param __str  The string to insert.
       *  @return  Reference to this string.
       *  @throw  std::length_error  If new length exceeds @c max_size().
       *
       *  Inserts value of @a __str starting at @a __pos1.  If adding
       *  characters causes the length to exceed max_size(),
       *  length_error is thrown.  The value of the string doesn't
       *  change if an error is thrown.
      */
      basic_string&
      insert(size_type __pos1, const basic_string& __str)
      { return this->insert(__pos1, __str, size_type(0), __str.size()); }

/**
       *  @brief  Insert a substring.
       *  @param __pos1  Iterator referencing location in string to insert at.
       *  @param __str  The string to insert.
       *  @param __pos2  Start of characters in str to insert.
       *  @param __n  Number of characters to insert.
       *  @return  Reference to this string.
       *  @throw  std::length_error  If new length exceeds @c max_size().
       *  @throw  std::out_of_range  If @a pos1 > size() or
       *  @a __pos2 > @a str.size().
       *
       *  Starting at @a pos1, insert @a __n character of @a __str
       *  beginning with @a __pos2.  If adding characters causes the
       *  length to exceed max_size(), length_error is thrown.  If @a
       *  __pos1 is beyond the end of this string or @a __pos2 is
       *  beyond the end of @a __str, out_of_range is thrown.  The
       *  value of the string doesn't change if an error is thrown.
      */
      basic_string&
      insert(size_type __pos1, const basic_string& __str,
	     size_type __pos2, size_type __n = npos)
      { return this->insert(__pos1, __str._M_data()
			    + __str._M_check(__pos2, "basic_string::insert"),
			    __str._M_limit(__pos2, __n)); }

/**
       *  @brief  Insert a C string.
       *  @param __pos  Iterator referencing location in string to insert at.
       *  @param __s  The C string to insert.
       *  @return  Reference to this string.
       *  @throw  std::length_error  If new length exceeds @c max_size().
       *  @throw  std::out_of_range  If @a pos is beyond the end of this
       *  string.
       *
       *  Inserts the first @a n characters of @a __s starting at @a __pos.  If
       *  adding characters causes the length to exceed max_size(),
       *  length_error is thrown.  If @a __pos is beyond end(), out_of_range is
       *  thrown.  The value of the string doesn't change if an error is
       *  thrown.
      */
      basic_string&
      insert(size_type __pos, const _CharT* __s)
      {
	__glibcxx_requires_string(__s);
	return this->insert(__pos, __s, traits_type::length(__s));
      }

/**
       *  @brief  Insert one character.
       *  @param __p  Iterator referencing position in string to insert at.
       *  @param __c  The character to insert.
       *  @return  Iterator referencing newly inserted char.
       *  @throw  std::length_error  If new length exceeds @c max_size().
       *
       *  Inserts character @a __c at position referenced by @a __p.
       *  If adding character causes the length to exceed max_size(),
       *  length_error is thrown.  If @a __p is beyond end of string,
       *  out_of_range is thrown.  The value of the string doesn't
       *  change if an error is thrown.
      */
      iterator
      insert(iterator __p, _CharT __c)
      {
	_GLIBCXX_DEBUG_PEDASSERT(__p >= _M_ibegin() && __p <= _M_iend());
	const size_type __pos = __p - _M_ibegin();
	_M_replace_aux(__pos, size_type(0), size_type(1), __c);
	_M_rep()->_M_set_leaked();
	return iterator(_M_data() + __pos);
      }

/**
       *  @brief  Insert a string_view.
       *  @param __pos  Iterator referencing position in string to insert at.
       *  @param __svt  The object convertible to string_view to insert from.
       *  @param __pos  Iterator referencing position in string_view to insert
       *  from.
       *  @param __n    The number of characters to insert.
       *  @return  Reference to this string.
      */
      template<typename _Tp>
        _If_sv<_Tp, basic_string&>
        insert(size_type __pos1, const _Tp& __svt,
	       size_type __pos2, size_type __n = npos)
	{
	  __sv_type __sv = __svt;
	  return this->replace(__pos1, size_type(0), __sv.data()
			       + __sv._M_check(__pos2, "basic_string::insert"),
			       __sv._M_limit(__pos2, __n));
	}
#endif // C++17

/**
       *  @brief  Remove characters.
       *  @param __pos  Index of first character to remove (default 0).
       *  @param __n  Number of characters to remove (default remainder).
       *  @return  Reference to this string.
       *  @throw  std::out_of_range  If @a pos is beyond the end of this
       *  string.
       *
       *  Removes @a __n characters from this string starting at @a
       *  __pos.  The length of the string is reduced by @a __n.  If
       *  there are < @a __n characters to remove, the remainder of
       *  the string is truncated.  If @a __p is beyond end of string,
       *  out_of_range is thrown.  The value of the string doesn't
       *  change if an error is thrown.
      */
      basic_string&
      erase(size_type __pos = 0, size_type __n = npos)
      { 
	_M_mutate(_M_check(__pos, "basic_string::erase"),
		  _M_limit(__pos, __n), size_type(0));
	return *this;
      }

/**
       *  @brief  Remove one character.
       *  @param __position  Iterator referencing the character to remove.
       *  @return  iterator referencing same location after removal.
       *
       *  Removes the character at @a __position from this string. The value
       *  of the string doesn't change if an error is thrown.
      */
      iterator
      erase(iterator __position)
      {
	_GLIBCXX_DEBUG_PEDASSERT(__position >= _M_ibegin()
				 && __position < _M_iend());
	const size_type __pos = __position - _M_ibegin();
	_M_mutate(__pos, size_type(1), size_type(0));
	_M_rep()->_M_set_leaked();
	return iterator(_M_data() + __pos);
      }

/**
       *  @brief  Remove a range of characters.
       *  @param __first  Iterator referencing the first character to remove.
       *  @param __last  Iterator referencing the end of the range.
       *  @return  Iterator referencing location of first after removal.
       *
       *  Removes the characters in the range [first,last) from this string.
       *  The value of the string doesn't change if an error is thrown.
      */
      iterator
      erase(iterator __first, iterator __last);
 
#if __cplusplus >= 201103L
      /**
       *  @brief  Remove the last character.
       *
       *  The string must be non-empty.
       */
      void
      pop_back() // FIXME C++11: should be noexcept.
      {
	__glibcxx_assert(!empty());
	erase(size() - 1, 1);
      }
#endif // C++11

/**
       *  @brief  Replace range of characters with string.
       *  @param __i1  Iterator referencing start of range to replace.
       *  @param __i2  Iterator referencing end of range to replace.
       *  @param __str  String value to insert.
       *  @return  Reference to this string.
       *  @throw  std::length_error  If new length exceeds @c max_size().
       *
       *  Removes the characters in the range [__i1,__i2).  In place,
       *  the value of @a __str is inserted.  If the length of result
       *  exceeds max_size(), length_error is thrown.  The value of
       *  the string doesn't change if an error is thrown.
      */
      basic_string&
      replace(iterator __i1, iterator __i2, const basic_string& __str)
      { return this->replace(__i1, __i2, __str._M_data(), __str.size()); }

/**
       *  @brief  Replace range of characters with C substring.
       *  @param __i1  Iterator referencing start of range to replace.
       *  @param __i2  Iterator referencing end of range to replace.
       *  @param __s  C string value to insert.
       *  @param __n  Number of characters from s to insert.
       *  @return  Reference to this string.
       *  @throw  std::length_error  If new length exceeds @c max_size().
       *
       *  Removes the characters in the range [__i1,__i2).  In place,
       *  the first @a __n characters of @a __s are inserted.  If the
       *  length of result exceeds max_size(), length_error is thrown.
       *  The value of the string doesn't change if an error is
       *  thrown.
      */
      basic_string&
      replace(iterator __i1, iterator __i2, const _CharT* __s, size_type __n)
      {
	_GLIBCXX_DEBUG_PEDASSERT(_M_ibegin() <= __i1 && __i1 <= __i2
				 && __i2 <= _M_iend());
	return this->replace(__i1 - _M_ibegin(), __i2 - __i1, __s, __n);
      }

/**
       *  @brief  Replace range of characters with C string.
       *  @param __i1  Iterator referencing start of range to replace.
       *  @param __i2  Iterator referencing end of range to replace.
       *  @param __s  C string value to insert.
       *  @return  Reference to this string.
       *  @throw  std::length_error  If new length exceeds @c max_size().
       *
       *  Removes the characters in the range [__i1,__i2).  In place,
       *  the characters of @a __s are inserted.  If the length of
       *  result exceeds max_size(), length_error is thrown.  The
       *  value of the string doesn't change if an error is thrown.
      */
      basic_string&
      replace(iterator __i1, iterator __i2, const _CharT* __s)
      {
	__glibcxx_requires_string(__s);
	return this->replace(__i1, __i2, __s, traits_type::length(__s));
      }

/**
       *  @brief  Replace range of characters with multiple characters
       *  @param __i1  Iterator referencing start of range to replace.
       *  @param __i2  Iterator referencing end of range to replace.
       *  @param __n  Number of characters to insert.
       *  @param __c  Character to insert.
       *  @return  Reference to this string.
       *  @throw  std::length_error  If new length exceeds @c max_size().
       *
       *  Removes the characters in the range [__i1,__i2).  In place,
       *  @a __n copies of @a __c are inserted.  If the length of
       *  result exceeds max_size(), length_error is thrown.  The
       *  value of the string doesn't change if an error is thrown.
      */
      basic_string&
      replace(iterator __i1, iterator __i2, size_type __n, _CharT __c)
      {
	_GLIBCXX_DEBUG_PEDASSERT(_M_ibegin() <= __i1 && __i1 <= __i2
				 && __i2 <= _M_iend());
	return _M_replace_aux(__i1 - _M_ibegin(), __i2 - __i1, __n, __c);
      }

// Specializations for the common case of pointer and iterator:
      // useful to avoid the overhead of temporary buffering in _M_replace.
      basic_string&
      replace(iterator __i1, iterator __i2, _CharT* __k1, _CharT* __k2)
      {
	_GLIBCXX_DEBUG_PEDASSERT(_M_ibegin() <= __i1 && __i1 <= __i2
				 && __i2 <= _M_iend());
	__glibcxx_requires_valid_range(__k1, __k2);
	return this->replace(__i1 - _M_ibegin(), __i2 - __i1,
			     __k1, __k2 - __k1);
      }

basic_string&
      replace(iterator __i1, iterator __i2,
	      const _CharT* __k1, const _CharT* __k2)
      {
	_GLIBCXX_DEBUG_PEDASSERT(_M_ibegin() <= __i1 && __i1 <= __i2
				 && __i2 <= _M_iend());
	__glibcxx_requires_valid_range(__k1, __k2);
	return this->replace(__i1 - _M_ibegin(), __i2 - __i1,
			     __k1, __k2 - __k1);
      }

basic_string&
      replace(iterator __i1, iterator __i2, iterator __k1, iterator __k2)
      {
	_GLIBCXX_DEBUG_PEDASSERT(_M_ibegin() <= __i1 && __i1 <= __i2
				 && __i2 <= _M_iend());
	__glibcxx_requires_valid_range(__k1, __k2);
	return this->replace(__i1 - _M_ibegin(), __i2 - __i1,
			     __k1.base(), __k2 - __k1);
      }

basic_string&
      replace(iterator __i1, iterator __i2,
	      const_iterator __k1, const_iterator __k2)
      {
	_GLIBCXX_DEBUG_PEDASSERT(_M_ibegin() <= __i1 && __i1 <= __i2
				 && __i2 <= _M_iend());
	__glibcxx_requires_valid_range(__k1, __k2);
	return this->replace(__i1 - _M_ibegin(), __i2 - __i1,
			     __k1.base(), __k2 - __k1);
      }

#if __cplusplus >= 201103L
      /**
       *  @brief  Replace range of characters with initializer_list.
       *  @param __i1  Iterator referencing start of range to replace.
       *  @param __i2  Iterator referencing end of range to replace.
       *  @param __l  The initializer_list of characters to insert.
       *  @return  Reference to this string.
       *  @throw  std::length_error  If new length exceeds @c max_size().
       *
       *  Removes the characters in the range [__i1,__i2).  In place,
       *  characters in the range [__k1,__k2) are inserted.  If the
       *  length of result exceeds max_size(), length_error is thrown.
       *  The value of the string doesn't change if an error is
       *  thrown.
      */
      basic_string& replace(iterator __i1, iterator __i2,
			    initializer_list<_CharT> __l)
      { return this->replace(__i1, __i2, __l.begin(), __l.end()); }
#endif // C++11

/**
       *  @brief  Replace range of characters with string_view.
       *  @param __pos1  The position to replace at.
       *  @param __n1    The number of characters to replace.
       *  @param __svt   The object convertible to string_view to insert from.
       *  @param __pos2  The position in the string_view to insert from.
       *  @param __n2    The number of characters to insert.
       *  @return  Reference to this string.
      */
      template<typename _Tp>
        _If_sv<_Tp, basic_string&>
        replace(size_type __pos1, size_type __n1, const _Tp& __svt,
		size_type __pos2, size_type __n2 = npos)
	{
	  __sv_type __sv = __svt;
	  return this->replace(__pos1, __n1,
	      __sv.data() + __sv._M_check(__pos2, "basic_string::replace"),
	      __sv._M_limit(__pos2, __n2));
	}

private:
      template<class _Integer>
	basic_string&
	_M_replace_dispatch(iterator __i1, iterator __i2, _Integer __n,
			    _Integer __val, __true_type)
        { return _M_replace_aux(__i1 - _M_ibegin(), __i2 - __i1, __n, __val); }

template<class _InputIterator>
	basic_string&
	_M_replace_dispatch(iterator __i1, iterator __i2, _InputIterator __k1,
			    _InputIterator __k2, __false_type);

basic_string&
      _M_replace_aux(size_type __pos1, size_type __n1, size_type __n2,
		     _CharT __c);

basic_string&
      _M_replace_safe(size_type __pos1, size_type __n1, const _CharT* __s,
		      size_type __n2);

// _S_construct_aux is used to implement the 21.3.1 para 15 which
      // requires special behaviour if _InIter is an integral type
      template<class _InIterator>
        static _CharT*
        _S_construct_aux(_InIterator __beg, _InIterator __end,
			 const _Alloc& __a, __false_type)
	{
          typedef typename iterator_traits<_InIterator>::iterator_category _Tag;
          return _S_construct(__beg, __end, __a, _Tag());
	}

// _GLIBCXX_RESOLVE_LIB_DEFECTS
      // 438. Ambiguity in the "do the right thing" clause
      template<class _Integer>
        static _CharT*
        _S_construct_aux(_Integer __beg, _Integer __end,
			 const _Alloc& __a, __true_type)
        { return _S_construct_aux_2(static_cast<size_type>(__beg),
				    __end, __a); }

static _CharT*
      _S_construct_aux_2(size_type __req, _CharT __c, const _Alloc& __a)
      { return _S_construct(__req, __c, __a); }

template<class _InIterator>
        static _CharT*
        _S_construct(_InIterator __beg, _InIterator __end, const _Alloc& __a)
	{
	  typedef typename std::__is_integer<_InIterator>::__type _Integral;
	  return _S_construct_aux(__beg, __end, __a, _Integral());
        }

// For Input Iterators, used in istreambuf_iterators, etc.
      template<class _InIterator>
        static _CharT*
         _S_construct(_InIterator __beg, _InIterator __end, const _Alloc& __a,
		      input_iterator_tag);

// For forward_iterators up to random_access_iterators, used for
      // string::iterator, _CharT*, etc.
      template<class _FwdIterator>
        static _CharT*
        _S_construct(_FwdIterator __beg, _FwdIterator __end, const _Alloc& __a,
		     forward_iterator_tag);

static _CharT*
      _S_construct(size_type __req, _CharT __c, const _Alloc& __a);

public:

/**
       *  @brief  Swap contents with another string.
       *  @param __s  String to swap with.
       *
       *  Exchanges the contents of this string with that of @a __s in constant
       *  time.
      */
      // PR 58265, this should be noexcept.
      void
      swap(basic_string& __s);

/**
       *  @brief  Return copy of allocator used to construct this string.
      */
      allocator_type
      get_allocator() const _GLIBCXX_NOEXCEPT
      { return _M_dataplus; }

/**
       *  @brief  Find last position of a C string.
       *  @param __s  C string to locate.
       *  @param __pos  Index of character to start search at (default end).
       *  @return  Index of start of  last occurrence.
       *
       *  Starting from @a __pos, searches backward for the value of
       *  @a __s within this string.  If found, returns the index
       *  where it begins.  If not found, returns npos.
      */
      size_type
      rfind(const _CharT* __s, size_type __pos = npos) const _GLIBCXX_NOEXCEPT
      {
	__glibcxx_requires_string(__s);
	return this->rfind(__s, __pos, traits_type::length(__s));
      }

/**
       *  @brief  Find position of a character.
       *  @param __c  Character to locate.
       *  @param __pos  Index of character to search from (default 0).
       *  @return  Index of first occurrence.
       *
       *  Starting from @a __pos, searches forward for the character
       *  @a __c within this string.  If found, returns the index
       *  where it was found.  If not found, returns npos.
       *
       *  Note: equivalent to find(__c, __pos).
      */
      size_type
      find_first_of(_CharT __c, size_type __pos = 0) const _GLIBCXX_NOEXCEPT
      { return this->find(__c, __pos); }

/**
       *  @brief  Find last position of a character.
       *  @param __c  Character to locate.
       *  @param __pos  Index of character to search back from (default end).
       *  @return  Index of last occurrence.
       *
       *  Starting from @a __pos, searches backward for @a __c within
       *  this string.  If found, returns the index where it was
       *  found.  If not found, returns npos.
       *
       *  Note: equivalent to rfind(__c, __pos).
      */
      size_type
      find_last_of(_CharT __c, size_type __pos = npos) const _GLIBCXX_NOEXCEPT
      { return this->rfind(__c, __pos); }

#if __cplusplus > 201402L
      /**
       *  @brief  Find position of a character not in a string_view.
       *  @param __svt  An object convertible to string_view containing
       *                characters to avoid.
       *  @param __pos  Index of character to search from (default 0).
       *  @return  Index of first occurrence.
       */
      template<typename _Tp>
	_If_sv<_Tp, size_type>
	find_first_not_of(const _Tp& __svt, size_type __pos = 0) const
	noexcept(is_same<_Tp, __sv_type>::value)
	{
	  __sv_type __sv = __svt;
	  return this->find_first_not_of(__sv.data(), __pos, __sv.size());
	}
#endif // C++17

int __r = traits_type::compare(_M_data(), __str.data(), __len);
	if (!__r)
	  __r = _S_compare(__size, __osize);
	return __r;
      }

#if __cplusplus > 201402L
      /**
       *  @brief  Compare to a string_view.
       *  @param __svt An object convertible to string_view to compare against.
       *  @return  Integer < 0, 0, or > 0.
       */
      template<typename _Tp>
	_If_sv<_Tp, int>
	compare(const _Tp& __svt) const
	noexcept(is_same<_Tp, __sv_type>::value)
	{
	   __sv_type __sv = __svt;
	  const size_type __size = this->size();
	  const size_type __osize = __sv.size();
	  const size_type __len = std::min(__size, __osize);

int __r = traits_type::compare(_M_data(), __sv.data(), __len);
	  if (!__r)
	    __r = _S_compare(__size, __osize);
	  return __r;
	}

/**
       *  @brief  Compare to a string_view.
       *  @param __pos1  A position in the string to start comparing from.
       *  @param __n1  The number of characters to compare.
       *  @param __svt   An object convertible to string_view to compare
       *                 against.
       *  @param __pos2  A position in the string_view to start comparing from.
       *  @param __n2  The number of characters to compare.
       *  @return  Integer < 0, 0, or > 0.
       */
      template<typename _Tp>
	_If_sv<_Tp, int>
	compare(size_type __pos1, size_type __n1, const _Tp& __svt,
		size_type __pos2, size_type __n2 = npos) const
	noexcept(is_same<_Tp, __sv_type>::value)
	{
	  __sv_type __sv = __svt;
	  return __sv_type(*this)
	    .substr(__pos1, __n1).compare(__sv.substr(__pos2, __n2));
	}
#endif // C++17

# ifdef _GLIBCXX_TM_TS_INTERNAL
      friend void
      ::_txnal_cow_string_C1_for_exceptions(void* that, const char* s,
					    void* exc);
      friend const char*
      ::_txnal_cow_string_c_str(const void *that);
      friend void
      ::_txnal_cow_string_D1(void *that);
      friend void
      ::_txnal_cow_string_D1_commit(void *that);
# endif
  };
#endif  // !_GLIBCXX_USE_CXX11_ABI

#if __cpp_deduction_guides >= 201606
_GLIBCXX_BEGIN_NAMESPACE_CXX11
  template<typename _InputIterator, typename _CharT
	     = typename iterator_traits<_InputIterator>::value_type,
	   typename _Allocator = allocator<_CharT>,
	   typename = _RequireInputIter<_InputIterator>,
	   typename = _RequireAllocator<_Allocator>>
    basic_string(_InputIterator, _InputIterator, _Allocator = _Allocator())
      -> basic_string<_CharT, char_traits<_CharT>, _Allocator>;

// _GLIBCXX_RESOLVE_LIB_DEFECTS
  // 3075. basic_string needs deduction guides from basic_string_view
  template<typename _CharT, typename _Traits,
	   typename _Allocator = allocator<_CharT>,
	   typename = _RequireAllocator<_Allocator>>
    basic_string(basic_string_view<_CharT, _Traits>, const _Allocator& = _Allocator())
      -> basic_string<_CharT, _Traits, _Allocator>;

template<typename _CharT, typename _Traits,
	   typename _Allocator = allocator<_CharT>,
	   typename = _RequireAllocator<_Allocator>>
    basic_string(basic_string_view<_CharT, _Traits>,
		 typename basic_string<_CharT, _Traits, _Allocator>::size_type,
		 typename basic_string<_CharT, _Traits, _Allocator>::size_type,
		 const _Allocator& = _Allocator())
      -> basic_string<_CharT, _Traits, _Allocator>;
_GLIBCXX_END_NAMESPACE_CXX11
#endif

// operator+
  /**
   *  @brief  Concatenate two strings.
   *  @param __lhs  First string.
   *  @param __rhs  Last string.
   *  @return  New string with value of @a __lhs followed by @a __rhs.
   */
  template<typename _CharT, typename _Traits, typename _Alloc>
    basic_string<_CharT, _Traits, _Alloc>
    operator+(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
	      const basic_string<_CharT, _Traits, _Alloc>& __rhs)
    {
      basic_string<_CharT, _Traits, _Alloc> __str(__lhs);
      __str.append(__rhs);
      return __str;
    }

/**
   *  @brief  Concatenate C string and string.
   *  @param __lhs  First string.
   *  @param __rhs  Last string.
   *  @return  New string with value of @a __lhs followed by @a __rhs.
   */
  template<typename _CharT, typename _Traits, typename _Alloc>
    basic_string<_CharT,_Traits,_Alloc>
    operator+(const _CharT* __lhs,
	      const basic_string<_CharT,_Traits,_Alloc>& __rhs);

/**
   *  @brief  Concatenate character and string.
   *  @param __lhs  First string.
   *  @param __rhs  Last string.
   *  @return  New string with @a __lhs followed by @a __rhs.
   */
  template<typename _CharT, typename _Traits, typename _Alloc>
    basic_string<_CharT,_Traits,_Alloc>
    operator+(_CharT __lhs, const basic_string<_CharT,_Traits,_Alloc>& __rhs);

/**
   *  @brief  Concatenate string and C string.
   *  @param __lhs  First string.
   *  @param __rhs  Last string.
   *  @return  New string with @a __lhs followed by @a __rhs.
   */
  template<typename _CharT, typename _Traits, typename _Alloc>
    inline basic_string<_CharT, _Traits, _Alloc>
    operator+(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
	      const _CharT* __rhs)
    {
      basic_string<_CharT, _Traits, _Alloc> __str(__lhs);
      __str.append(__rhs);
      return __str;
    }

/**
   *  @brief  Concatenate string and character.
   *  @param __lhs  First string.
   *  @param __rhs  Last string.
   *  @return  New string with @a __lhs followed by @a __rhs.
   */
  template<typename _CharT, typename _Traits, typename _Alloc>
    inline basic_string<_CharT, _Traits, _Alloc>
    operator+(const basic_string<_CharT, _Traits, _Alloc>& __lhs, _CharT __rhs)
    {
      typedef basic_string<_CharT, _Traits, _Alloc>	__string_type;
      typedef typename __string_type::size_type		__size_type;
      __string_type __str(__lhs);
      __str.append(__size_type(1), __rhs);
      return __str;
    }

#if __cplusplus >= 201103L
  template<typename _CharT, typename _Traits, typename _Alloc>
    inline basic_string<_CharT, _Traits, _Alloc>
    operator+(basic_string<_CharT, _Traits, _Alloc>&& __lhs,
	      const basic_string<_CharT, _Traits, _Alloc>& __rhs)
    { return std::move(__lhs.append(__rhs)); }

template<typename _CharT, typename _Traits, typename _Alloc>
    inline basic_string<_CharT, _Traits, _Alloc>
    operator+(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
	      basic_string<_CharT, _Traits, _Alloc>&& __rhs)
    { return std::move(__rhs.insert(0, __lhs)); }

template<typename _CharT, typename _Traits, typename _Alloc>
    inline basic_string<_CharT, _Traits, _Alloc>
    operator+(basic_string<_CharT, _Traits, _Alloc>&& __lhs,
	      basic_string<_CharT, _Traits, _Alloc>&& __rhs)
    {
      const auto __size = __lhs.size() + __rhs.size();
      const bool __cond = (__size > __lhs.capacity()
			   && __size <= __rhs.capacity());
      return __cond ? std::move(__rhs.insert(0, __lhs))
	            : std::move(__lhs.append(__rhs));
    }

template<typename _CharT, typename _Traits, typename _Alloc>
    inline basic_string<_CharT, _Traits, _Alloc>
    operator+(const _CharT* __lhs,
	      basic_string<_CharT, _Traits, _Alloc>&& __rhs)
    { return std::move(__rhs.insert(0, __lhs)); }

template<typename _CharT, typename _Traits, typename _Alloc>
    inline basic_string<_CharT, _Traits, _Alloc>
    operator+(_CharT __lhs,
	      basic_string<_CharT, _Traits, _Alloc>&& __rhs)
    { return std::move(__rhs.insert(0, 1, __lhs)); }

template<typename _CharT, typename _Traits, typename _Alloc>
    inline basic_string<_CharT, _Traits, _Alloc>
    operator+(basic_string<_CharT, _Traits, _Alloc>&& __lhs,
	      const _CharT* __rhs)
    { return std::move(__lhs.append(__rhs)); }

template<typename _CharT, typename _Traits, typename _Alloc>
    inline basic_string<_CharT, _Traits, _Alloc>
    operator+(basic_string<_CharT, _Traits, _Alloc>&& __lhs,
	      _CharT __rhs)
    { return std::move(__lhs.append(1, __rhs)); }
#endif

// operator ==
  /**
   *  @brief  Test equivalence of two strings.
   *  @param __lhs  First string.
   *  @param __rhs  Second string.
   *  @return  True if @a __lhs.compare(@a __rhs) == 0.  False otherwise.
   */
  template<typename _CharT, typename _Traits, typename _Alloc>
    inline bool
    operator==(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
	       const basic_string<_CharT, _Traits, _Alloc>& __rhs)
    _GLIBCXX_NOEXCEPT
    { return __lhs.compare(__rhs) == 0; }

template<typename _CharT>
    inline
    typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value, bool>::__type
    operator==(const basic_string<_CharT>& __lhs,
	       const basic_string<_CharT>& __rhs) _GLIBCXX_NOEXCEPT
    { return (__lhs.size() == __rhs.size()
	      && !std::char_traits<_CharT>::compare(__lhs.data(), __rhs.data(),
						    __lhs.size())); }

/**
   *  @brief  Test equivalence of C string and string.
   *  @param __lhs  C string.
   *  @param __rhs  String.
   *  @return  True if @a __rhs.compare(@a __lhs) == 0.  False otherwise.
   */
  template<typename _CharT, typename _Traits, typename _Alloc>
    inline bool
    operator==(const _CharT* __lhs,
	       const basic_string<_CharT, _Traits, _Alloc>& __rhs)
    { return __rhs.compare(__lhs) == 0; }

/**
   *  @brief  Test equivalence of string and C string.
   *  @param __lhs  String.
   *  @param __rhs  C string.
   *  @return  True if @a __lhs.compare(@a __rhs) == 0.  False otherwise.
   */
  template<typename _CharT, typename _Traits, typename _Alloc>
    inline bool
    operator==(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
	       const _CharT* __rhs)
    { return __lhs.compare(__rhs) == 0; }

// operator !=
  /**
   *  @brief  Test difference of two strings.
   *  @param __lhs  First string.
   *  @param __rhs  Second string.
   *  @return  True if @a __lhs.compare(@a __rhs) != 0.  False otherwise.
   */
  template<typename _CharT, typename _Traits, typename _Alloc>
    inline bool
    operator!=(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
	       const basic_string<_CharT, _Traits, _Alloc>& __rhs)
    _GLIBCXX_NOEXCEPT
    { return !(__lhs == __rhs); }

/**
   *  @brief  Test difference of C string and string.
   *  @param __lhs  C string.
   *  @param __rhs  String.
   *  @return  True if @a __rhs.compare(@a __lhs) != 0.  False otherwise.
   */
  template<typename _CharT, typename _Traits, typename _Alloc>
    inline bool
    operator!=(const _CharT* __lhs,
	       const basic_string<_CharT, _Traits, _Alloc>& __rhs)
    { return !(__lhs == __rhs); }

/**
   *  @brief  Test difference of string and C string.
   *  @param __lhs  String.
   *  @param __rhs  C string.
   *  @return  True if @a __lhs.compare(@a __rhs) != 0.  False otherwise.
   */
  template<typename _CharT, typename _Traits, typename _Alloc>
    inline bool
    operator!=(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
	       const _CharT* __rhs)
    { return !(__lhs == __rhs); }

// operator <
  /**
   *  @brief  Test if string precedes string.
   *  @param __lhs  First string.
   *  @param __rhs  Second string.
   *  @return  True if @a __lhs precedes @a __rhs.  False otherwise.
   */
  template<typename _CharT, typename _Traits, typename _Alloc>
    inline bool
    operator<(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
	      const basic_string<_CharT, _Traits, _Alloc>& __rhs)
    _GLIBCXX_NOEXCEPT
    { return __lhs.compare(__rhs) < 0; }

/**
   *  @brief  Test if string precedes C string.
   *  @param __lhs  String.
   *  @param __rhs  C string.
   *  @return  True if @a __lhs precedes @a __rhs.  False otherwise.
   */
  template<typename _CharT, typename _Traits, typename _Alloc>
    inline bool
    operator<(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
	      const _CharT* __rhs)
    { return __lhs.compare(__rhs) < 0; }

/**
   *  @brief  Test if C string precedes string.
   *  @param __lhs  C string.
   *  @param __rhs  String.
   *  @return  True if @a __lhs precedes @a __rhs.  False otherwise.
   */
  template<typename _CharT, typename _Traits, typename _Alloc>
    inline bool
    operator<(const _CharT* __lhs,
	      const basic_string<_CharT, _Traits, _Alloc>& __rhs)
    { return __rhs.compare(__lhs) > 0; }

// operator >
  /**
   *  @brief  Test if string follows string.
   *  @param __lhs  First string.
   *  @param __rhs  Second string.
   *  @return  True if @a __lhs follows @a __rhs.  False otherwise.
   */
  template<typename _CharT, typename _Traits, typename _Alloc>
    inline bool
    operator>(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
	      const basic_string<_CharT, _Traits, _Alloc>& __rhs)
    _GLIBCXX_NOEXCEPT
    { return __lhs.compare(__rhs) > 0; }

/**
   *  @brief  Test if string follows C string.
   *  @param __lhs  String.
   *  @param __rhs  C string.
   *  @return  True if @a __lhs follows @a __rhs.  False otherwise.
   */
  template<typename _CharT, typename _Traits, typename _Alloc>
    inline bool
    operator>(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
	      const _CharT* __rhs)
    { return __lhs.compare(__rhs) > 0; }

/**
   *  @brief  Test if C string follows string.
   *  @param __lhs  C string.
   *  @param __rhs  String.
   *  @return  True if @a __lhs follows @a __rhs.  False otherwise.
   */
  template<typename _CharT, typename _Traits, typename _Alloc>
    inline bool
    operator>(const _CharT* __lhs,
	      const basic_string<_CharT, _Traits, _Alloc>& __rhs)
    { return __rhs.compare(__lhs) < 0; }

// operator <=
  /**
   *  @brief  Test if string doesn't follow string.
   *  @param __lhs  First string.
   *  @param __rhs  Second string.
   *  @return  True if @a __lhs doesn't follow @a __rhs.  False otherwise.
   */
  template<typename _CharT, typename _Traits, typename _Alloc>
    inline bool
    operator<=(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
	       const basic_string<_CharT, _Traits, _Alloc>& __rhs)
    _GLIBCXX_NOEXCEPT
    { return __lhs.compare(__rhs) <= 0; }

/**
   *  @brief  Test if string doesn't follow C string.
   *  @param __lhs  String.
   *  @param __rhs  C string.
   *  @return  True if @a __lhs doesn't follow @a __rhs.  False otherwise.
   */
  template<typename _CharT, typename _Traits, typename _Alloc>
    inline bool
    operator<=(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
	       const _CharT* __rhs)
    { return __lhs.compare(__rhs) <= 0; }

/**
   *  @brief  Test if C string doesn't follow string.
   *  @param __lhs  C string.
   *  @param __rhs  String.
   *  @return  True if @a __lhs doesn't follow @a __rhs.  False otherwise.
   */
  template<typename _CharT, typename _Traits, typename _Alloc>
    inline bool
    operator<=(const _CharT* __lhs,
	       const basic_string<_CharT, _Traits, _Alloc>& __rhs)
    { return __rhs.compare(__lhs) >= 0; }

// operator >=
  /**
   *  @brief  Test if string doesn't precede string.
   *  @param __lhs  First string.
   *  @param __rhs  Second string.
   *  @return  True if @a __lhs doesn't precede @a __rhs.  False otherwise.
   */
  template<typename _CharT, typename _Traits, typename _Alloc>
    inline bool
    operator>=(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
	       const basic_string<_CharT, _Traits, _Alloc>& __rhs)
    _GLIBCXX_NOEXCEPT
    { return __lhs.compare(__rhs) >= 0; }

/**
   *  @brief  Test if string doesn't precede C string.
   *  @param __lhs  String.
   *  @param __rhs  C string.
   *  @return  True if @a __lhs doesn't precede @a __rhs.  False otherwise.
   */
  template<typename _CharT, typename _Traits, typename _Alloc>
    inline bool
    operator>=(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
	       const _CharT* __rhs)
    { return __lhs.compare(__rhs) >= 0; }

/**
   *  @brief  Test if C string doesn't precede string.
   *  @param __lhs  C string.
   *  @param __rhs  String.
   *  @return  True if @a __lhs doesn't precede @a __rhs.  False otherwise.
   */
  template<typename _CharT, typename _Traits, typename _Alloc>
    inline bool
    operator>=(const _CharT* __lhs,
	     const basic_string<_CharT, _Traits, _Alloc>& __rhs)
    { return __rhs.compare(__lhs) <= 0; }

/**
   *  @brief  Swap contents of two strings.
   *  @param __lhs  First string.
   *  @param __rhs  Second string.
   *
   *  Exchanges the contents of @a __lhs and @a __rhs in constant time.
   */
  template<typename _CharT, typename _Traits, typename _Alloc>
    inline void
    swap(basic_string<_CharT, _Traits, _Alloc>& __lhs,
	 basic_string<_CharT, _Traits, _Alloc>& __rhs)
    _GLIBCXX_NOEXCEPT_IF(noexcept(__lhs.swap(__rhs)))
    { __lhs.swap(__rhs); }

/**
   *  @brief  Read stream into a string.
   *  @param __is  Input stream.
   *  @param __str  Buffer to store into.
   *  @return  Reference to the input stream.
   *
   *  Stores characters from @a __is into @a __str until whitespace is
   *  found, the end of the stream is encountered, or str.max_size()
   *  is reached.  If is.width() is non-zero, that is the limit on the
   *  number of characters stored into @a __str.  Any previous
   *  contents of @a __str are erased.
   */
  template<typename _CharT, typename _Traits, typename _Alloc>
    basic_istream<_CharT, _Traits>&
    operator>>(basic_istream<_CharT, _Traits>& __is,
	       basic_string<_CharT, _Traits, _Alloc>& __str);

template<>
    basic_istream<char>&
    operator>>(basic_istream<char>& __is, basic_string<char>& __str);

/**
   *  @brief  Write string to a stream.
   *  @param __os  Output stream.
   *  @param __str  String to write out.
   *  @return  Reference to the output stream.
   *
   *  Output characters of @a __str into os following the same rules as for
   *  writing a C string.
   */
  template<typename _CharT, typename _Traits, typename _Alloc>
    inline basic_ostream<_CharT, _Traits>&
    operator<<(basic_ostream<_CharT, _Traits>& __os,
	       const basic_string<_CharT, _Traits, _Alloc>& __str)
    {
      // _GLIBCXX_RESOLVE_LIB_DEFECTS
      // 586. string inserter not a formatted function
      return __ostream_insert(__os, __str.data(), __str.size());
    }

/**
   *  @brief  Read a line from stream into a string.
   *  @param __is  Input stream.
   *  @param __str  Buffer to store into.
   *  @param __delim  Character marking end of line.
   *  @return  Reference to the input stream.
   *
   *  Stores characters from @a __is into @a __str until @a __delim is
   *  found, the end of the stream is encountered, or str.max_size()
   *  is reached.  Any previous contents of @a __str are erased.  If
   *  @a __delim is encountered, it is extracted but not stored into
   *  @a __str.
   */
  template<typename _CharT, typename _Traits, typename _Alloc>
    basic_istream<_CharT, _Traits>&
    getline(basic_istream<_CharT, _Traits>& __is,
	    basic_string<_CharT, _Traits, _Alloc>& __str, _CharT __delim);

/**
   *  @brief  Read a line from stream into a string.
   *  @param __is  Input stream.
   *  @param __str  Buffer to store into.
   *  @return  Reference to the input stream.
   *
   *  Stores characters from is into @a __str until &apos;\n&apos; is
   *  found, the end of the stream is encountered, or str.max_size()
   *  is reached.  Any previous contents of @a __str are erased.  If
   *  end of line is encountered, it is extracted but not stored into
   *  @a __str.
   */
  template<typename _CharT, typename _Traits, typename _Alloc>
    inline basic_istream<_CharT, _Traits>&
    getline(basic_istream<_CharT, _Traits>& __is,
	    basic_string<_CharT, _Traits, _Alloc>& __str)
    { return std::getline(__is, __str, __is.widen('\n')); }

#if __cplusplus >= 201103L
  /// Read a line from an rvalue stream into a string.
  template<typename _CharT, typename _Traits, typename _Alloc>
    inline basic_istream<_CharT, _Traits>&
    getline(basic_istream<_CharT, _Traits>&& __is,
	    basic_string<_CharT, _Traits, _Alloc>& __str, _CharT __delim)
    { return std::getline(__is, __str, __delim); }

/// Read a line from an rvalue stream into a string.
  template<typename _CharT, typename _Traits, typename _Alloc>
    inline basic_istream<_CharT, _Traits>&
    getline(basic_istream<_CharT, _Traits>&& __is,
	    basic_string<_CharT, _Traits, _Alloc>& __str)
    { return std::getline(__is, __str); }
#endif

template<>
    basic_istream<char>&
    getline(basic_istream<char>& __in, basic_string<char>& __str,
	    char __delim);

#ifdef _GLIBCXX_USE_WCHAR_T
  template<>
    basic_istream<wchar_t>&
    getline(basic_istream<wchar_t>& __in, basic_string<wchar_t>& __str,
	    wchar_t __delim);
#endif

_GLIBCXX_END_NAMESPACE_VERSION
} // namespace

#if __cplusplus >= 201103L

#include <ext/string_conversions.h>

namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
_GLIBCXX_BEGIN_NAMESPACE_CXX11

#if _GLIBCXX_USE_C99_STDLIB
  // 21.4 Numeric Conversions [string.conversions].
  inline int
  stoi(const string& __str, size_t* __idx = 0, int __base = 10)
  { return __gnu_cxx::__stoa<long, int>(&std::strtol, "stoi", __str.c_str(),
					__idx, __base); }

inline long
  stol(const string& __str, size_t* __idx = 0, int __base = 10)
  { return __gnu_cxx::__stoa(&std::strtol, "stol", __str.c_str(),
			     __idx, __base); }

inline unsigned long
  stoul(const string& __str, size_t* __idx = 0, int __base = 10)
  { return __gnu_cxx::__stoa(&std::strtoul, "stoul", __str.c_str(),
			     __idx, __base); }

inline long long
  stoll(const string& __str, size_t* __idx = 0, int __base = 10)
  { return __gnu_cxx::__stoa(&std::strtoll, "stoll", __str.c_str(),
			     __idx, __base); }

inline unsigned long long
  stoull(const string& __str, size_t* __idx = 0, int __base = 10)
  { return __gnu_cxx::__stoa(&std::strtoull, "stoull", __str.c_str(),
			     __idx, __base); }

// NB: strtof vs strtod.
  inline float
  stof(const string& __str, size_t* __idx = 0)
  { return __gnu_cxx::__stoa(&std::strtof, "stof", __str.c_str(), __idx); }

inline double
  stod(const string& __str, size_t* __idx = 0)
  { return __gnu_cxx::__stoa(&std::strtod, "stod", __str.c_str(), __idx); }

inline long double
  stold(const string& __str, size_t* __idx = 0)
  { return __gnu_cxx::__stoa(&std::strtold, "stold", __str.c_str(), __idx); }
#endif // _GLIBCXX_USE_C99_STDLIB

#if _GLIBCXX_USE_C99_STDIO
  // NB: (v)snprintf vs sprintf.

// DR 1261.
  inline string
  to_string(int __val)
  { return __gnu_cxx::__to_xstring<string>(&std::vsnprintf, 4 * sizeof(int),
					   "%d", __val); }

inline string
  to_string(unsigned __val)
  { return __gnu_cxx::__to_xstring<string>(&std::vsnprintf,
					   4 * sizeof(unsigned),
					   "%u", __val); }

inline string
  to_string(long __val)
  { return __gnu_cxx::__to_xstring<string>(&std::vsnprintf, 4 * sizeof(long),
					   "%ld", __val); }

inline string
  to_string(unsigned long __val)
  { return __gnu_cxx::__to_xstring<string>(&std::vsnprintf,
					   4 * sizeof(unsigned long),
					   "%lu", __val); }

inline string
  to_string(long long __val)
  { return __gnu_cxx::__to_xstring<string>(&std::vsnprintf,
					   4 * sizeof(long long),
					   "%lld", __val); }

inline string
  to_string(unsigned long long __val)
  { return __gnu_cxx::__to_xstring<string>(&std::vsnprintf,
					   4 * sizeof(unsigned long long),
					   "%llu", __val); }

inline string
  to_string(float __val)
  {
    const int __n = 
      __gnu_cxx::__numeric_traits<float>::__max_exponent10 + 20;
    return __gnu_cxx::__to_xstring<string>(&std::vsnprintf, __n,
					   "%f", __val);
  }

inline string
  to_string(double __val)
  {
    const int __n = 
      __gnu_cxx::__numeric_traits<double>::__max_exponent10 + 20;
    return __gnu_cxx::__to_xstring<string>(&std::vsnprintf, __n,
					   "%f", __val);
  }

inline string
  to_string(long double __val)
  {
    const int __n = 
      __gnu_cxx::__numeric_traits<long double>::__max_exponent10 + 20;
    return __gnu_cxx::__to_xstring<string>(&std::vsnprintf, __n,
					   "%Lf", __val);
  }
#endif // _GLIBCXX_USE_C99_STDIO

#if defined(_GLIBCXX_USE_WCHAR_T) && _GLIBCXX_USE_C99_WCHAR
  inline int 
  stoi(const wstring& __str, size_t* __idx = 0, int __base = 10)
  { return __gnu_cxx::__stoa<long, int>(&std::wcstol, "stoi", __str.c_str(),
					__idx, __base); }

inline long 
  stol(const wstring& __str, size_t* __idx = 0, int __base = 10)
  { return __gnu_cxx::__stoa(&std::wcstol, "stol", __str.c_str(),
			     __idx, __base); }

inline unsigned long
  stoul(const wstring& __str, size_t* __idx = 0, int __base = 10)
  { return __gnu_cxx::__stoa(&std::wcstoul, "stoul", __str.c_str(),
			     __idx, __base); }

inline long long
  stoll(const wstring& __str, size_t* __idx = 0, int __base = 10)
  { return __gnu_cxx::__stoa(&std::wcstoll, "stoll", __str.c_str(),
			     __idx, __base); }

inline unsigned long long
  stoull(const wstring& __str, size_t* __idx = 0, int __base = 10)
  { return __gnu_cxx::__stoa(&std::wcstoull, "stoull", __str.c_str(),
			     __idx, __base); }

// NB: wcstof vs wcstod.
  inline float
  stof(const wstring& __str, size_t* __idx = 0)
  { return __gnu_cxx::__stoa(&std::wcstof, "stof", __str.c_str(), __idx); }

inline double
  stod(const wstring& __str, size_t* __idx = 0)
  { return __gnu_cxx::__stoa(&std::wcstod, "stod", __str.c_str(), __idx); }

inline long double
  stold(const wstring& __str, size_t* __idx = 0)
  { return __gnu_cxx::__stoa(&std::wcstold, "stold", __str.c_str(), __idx); }

#ifndef _GLIBCXX_HAVE_BROKEN_VSWPRINTF
  // DR 1261.
  inline wstring
  to_wstring(int __val)
  { return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf, 4 * sizeof(int),
					    L"%d", __val); }

inline wstring
  to_wstring(unsigned __val)
  { return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf,
					    4 * sizeof(unsigned),
					    L"%u", __val); }

inline wstring
  to_wstring(long __val)
  { return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf, 4 * sizeof(long),
					    L"%ld", __val); }

inline wstring
  to_wstring(unsigned long __val)
  { return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf,
					    4 * sizeof(unsigned long),
					    L"%lu", __val); }

inline wstring
  to_wstring(long long __val)
  { return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf,
					    4 * sizeof(long long),
					    L"%lld", __val); }

inline wstring
  to_wstring(unsigned long long __val)
  { return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf,
					    4 * sizeof(unsigned long long),
					    L"%llu", __val); }

inline wstring
  to_wstring(float __val)
  {
    const int __n =
      __gnu_cxx::__numeric_traits<float>::__max_exponent10 + 20;
    return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf, __n,
					    L"%f", __val);
  }

inline wstring
  to_wstring(double __val)
  {
    const int __n =
      __gnu_cxx::__numeric_traits<double>::__max_exponent10 + 20;
    return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf, __n,
					    L"%f", __val);
  }

inline wstring
  to_wstring(long double __val)
  {
    const int __n =
      __gnu_cxx::__numeric_traits<long double>::__max_exponent10 + 20;
    return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf, __n,
					    L"%Lf", __val);
  }
#endif // _GLIBCXX_HAVE_BROKEN_VSWPRINTF
#endif // _GLIBCXX_USE_WCHAR_T && _GLIBCXX_USE_C99_WCHAR

_GLIBCXX_END_NAMESPACE_CXX11
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace

#endif /* C++11 */

#if __cplusplus >= 201103L

#include <bits/functional_hash.h>

namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION

// DR 1182.

#ifndef _GLIBCXX_COMPATIBILITY_CXX0X
  /// std::hash specialization for string.
  template<>
    struct hash<string>
    : public __hash_base<size_t, string>
    {
      size_t
      operator()(const string& __s) const noexcept
      { return std::_Hash_impl::hash(__s.data(), __s.length()); }
    };

template<>
    struct __is_fast_hash<hash<string>> : std::false_type
    { };

#ifdef _GLIBCXX_USE_WCHAR_T
  /// std::hash specialization for wstring.
  template<>
    struct hash<wstring>
    : public __hash_base<size_t, wstring>
    {
      size_t
      operator()(const wstring& __s) const noexcept
      { return std::_Hash_impl::hash(__s.data(),
                                     __s.length() * sizeof(wchar_t)); }
    };

template<>
    struct __is_fast_hash<hash<wstring>> : std::false_type
    { };
#endif
#endif /* _GLIBCXX_COMPATIBILITY_CXX0X */

#ifdef _GLIBCXX_USE_C99_STDINT_TR1
  /// std::hash specialization for u16string.
  template<>
    struct hash<u16string>
    : public __hash_base<size_t, u16string>
    {
      size_t
      operator()(const u16string& __s) const noexcept
      { return std::_Hash_impl::hash(__s.data(),
                                     __s.length() * sizeof(char16_t)); }
    };

template<>
    struct __is_fast_hash<hash<u16string>> : std::false_type
    { };

/// std::hash specialization for u32string.
  template<>
    struct hash<u32string>
    : public __hash_base<size_t, u32string>
    {
      size_t
      operator()(const u32string& __s) const noexcept
      { return std::_Hash_impl::hash(__s.data(),
                                     __s.length() * sizeof(char32_t)); }
    };

template<>
    struct __is_fast_hash<hash<u32string>> : std::false_type
    { };
#endif

#if __cplusplus > 201103L

#define __cpp_lib_string_udls 201304

inline namespace literals
  {
  inline namespace string_literals
  {
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wliteral-suffix"
    _GLIBCXX_DEFAULT_ABI_TAG
    inline basic_string<char>
    operator""s(const char* __str, size_t __len)
    { return basic_string<char>{__str, __len}; }

#ifdef _GLIBCXX_USE_WCHAR_T
    _GLIBCXX_DEFAULT_ABI_TAG
    inline basic_string<wchar_t>
    operator""s(const wchar_t* __str, size_t __len)
    { return basic_string<wchar_t>{__str, __len}; }
#endif

#ifdef _GLIBCXX_USE_C99_STDINT_TR1
    _GLIBCXX_DEFAULT_ABI_TAG
    inline basic_string<char16_t>
    operator""s(const char16_t* __str, size_t __len)
    { return basic_string<char16_t>{__str, __len}; }

_GLIBCXX_DEFAULT_ABI_TAG
    inline basic_string<char32_t>
    operator""s(const char32_t* __str, size_t __len)
    { return basic_string<char32_t>{__str, __len}; }
#endif

#pragma GCC diagnostic pop
  } // inline namespace string_literals
  } // inline namespace literals

#endif // __cplusplus > 201103L

_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std

#endif // C++11

#endif /* _BASIC_STRING_H */

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