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gnu/gcc/d22b7d0195dbe3ebe52fd71f43f42aac956d3e5e/./libstdc++-v3/include/bits/cow_string.h
blob: 0f1a2e082d0a94528fa13fa122f2033b1771c078 [file]
// Definition of gcc4-compatible Copy-on-Write basic_string -*- C++ -*-
// Copyright (C) 1997-2026 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/cow_string.h
* This is an internal header file, included by other library headers.
* Do not attempt to use it directly. @headername{string}
*
* Defines the reference-counted COW string implementation.
*/
#ifndef _COW_STRING_H
#define _COW_STRING_H 1
#if ! _GLIBCXX_USE_CXX11_ABI
#include <ext/atomicity.h> // _Atomic_word, __is_single_threaded
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
/**
* @class basic_string basic_string.h <string>
* @brief Managing sequences of characters and character-like objects.
*
* @ingroup strings
* @ingroup sequences
* @headerfile string
* @since C++98
*
* @tparam _CharT Type of character
* @tparam _Traits Traits for character type, defaults to
* char_traits<_CharT>.
* @tparam _Alloc Allocator type, defaults to allocator<_CharT>.
*
* Meets the requirements of a <a href="tables.html#65">container</a>, a
* <a href="tables.html#66">reversible container</a>, and a
* <a href="tables.html#67">sequence</a>. Of the
* <a href="tables.html#68">optional sequence requirements</a>, only
* @c push_back, @c at, and @c %array access are supported.
*
* @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 Copy-On-Write C++ string implementation.
*/
// 21.3 Template class basic_string
template<typename _CharT, typename _Traits, typename _Alloc>
class basic_string
{
typedef typename __gnu_cxx::__alloc_traits<_Alloc>::template
rebind<_CharT>::other _CharT_alloc_type;
typedef __gnu_cxx::__alloc_traits<_CharT_alloc_type> _CharT_alloc_traits;
// Types:
public:
typedef _Traits traits_type;
typedef typename _Traits::char_type value_type;
typedef _Alloc allocator_type;
typedef typename _CharT_alloc_traits::size_type size_type;
typedef typename _CharT_alloc_traits::difference_type difference_type;
#if __cplusplus < 201103L
typedef typename _CharT_alloc_type::reference reference;
typedef typename _CharT_alloc_type::const_reference const_reference;
#else
typedef value_type& reference;
typedef const value_type& const_reference;
#endif
typedef typename _CharT_alloc_traits::pointer pointer;
typedef typename _CharT_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;
protected:
// type used for positions in insert, erase etc.
typedef iterator __const_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 __gnu_cxx::__alloc_traits<_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.
if (!__gnu_cxx::__is_single_threaded())
return __atomic_load_n(&this->_M_refcount, __ATOMIC_ACQUIRE) > 0;
#endif
return this->_M_refcount > 0;
}
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, static_cast<_CharT>(*__k1));
}
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(); }
#ifdef __glibcxx_string_view // >= C++17
// 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;
};
/**
* @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
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
_GLIBCXX_NOEXCEPT
#endif
#if __cpp_concepts && __glibcxx_type_trait_variable_templates
requires is_default_constructible_v<_Alloc>
#endif
#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)
: _M_dataplus(_S_construct(size_type(), _CharT(), __a), __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)
: _M_dataplus(__str._M_rep()->_M_grab(_Alloc(__str.get_allocator()),
__str.get_allocator()),
__str.get_allocator())
{ }
// _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, &apos;\\0&apos;
* has no special meaning.
*/
basic_string(const _CharT* __s, size_type __n,
const _Alloc& __a = _Alloc())
: _M_dataplus(_S_construct(__s, __s + __n, __a), __a)
{ }
/**
* @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(_S_construct(__s, __s ? __s + traits_type::length(__s) :
__s + npos, __a), __a)
{ }
/**
* @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())
: _M_dataplus(_S_construct(__n, __c, __a), __a)
{ }
#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(std::move(__str._M_dataplus))
{
#if _GLIBCXX_FULLY_DYNAMIC_STRING == 0
// Make __str use the shared empty string rep.
__str._M_data(_S_empty_rep()._M_refdata());
#else
// Rather than allocate an empty string for the rvalue string,
// just share ownership with it by incrementing the reference count.
// If the rvalue string was the unique owner then there are exactly
// two owners now.
if (_M_rep()->_M_is_shared())
__gnu_cxx::__atomic_add_dispatch(&_M_rep()->_M_refcount, 1);
else
_M_rep()->_M_refcount = 1;
#endif
}
#if __glibcxx_containers_ranges // C++ >= 23
/**
* @brief Construct a string from a range.
* @since C++23
*/
template<__detail::__container_compatible_range<_CharT> _Rg>
basic_string(from_range_t, _Rg&& __rg, const _Alloc& __a = _Alloc())
: basic_string(__a)
{
if constexpr (ranges::forward_range<_Rg> || ranges::sized_range<_Rg>)
{
const auto __n = static_cast<size_type>(ranges::distance(__rg));
if (__n == 0)
return;
reserve(__n);
pointer __p = _M_data();
if constexpr (requires {
requires ranges::contiguous_range<_Rg>;
{ ranges::data(std::forward<_Rg>(__rg)) }
-> convertible_to<const _CharT*>;
})
_M_copy(__p, ranges::data(std::forward<_Rg>(__rg)), __n);
else
{
auto __first = ranges::begin(__rg);
const auto __last = ranges::end(__rg);
for (; __first != __last; ++__first)
traits_type::assign(*__p++, static_cast<_CharT>(*__first));
}
_M_rep()->_M_set_length_and_sharable(__n);
}
else
{
auto __first = ranges::begin(__rg);
const auto __last = ranges::end(__rg);
for (; __first != __last; ++__first)
push_back(*__first);
}
}
#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())
: _M_dataplus(_S_construct(__l.begin(), __l.end(), __a), __a)
{ }
basic_string(const basic_string& __str, const _Alloc& __a)
: _M_dataplus(__str._M_rep()->_M_grab(__a, __str.get_allocator()), __a)
{ }
basic_string(basic_string&& __str, const _Alloc& __a)
: _M_dataplus(__str._M_data(), __a)
{
if (__a == __str.get_allocator())
{
#if _GLIBCXX_FULLY_DYNAMIC_STRING == 0
__str._M_data(_S_empty_rep()._M_refdata());
#else
__str._M_data(_S_construct(size_type(), _CharT(), __a));
#endif
}
else
_M_dataplus._M_p = _S_construct(__str.begin(), __str.end(), __a);
}
#endif // C++11
#if __cplusplus >= 202100L
basic_string(nullptr_t) = delete;
basic_string& operator=(nullptr_t) = delete;
#endif // C++23
/**
* @brief Construct string as copy of a range.
* @param __beg Start of range.
* @param __end End of range.
* @param __a Allocator to use (default is default allocator).
*/
template<class _InputIterator>
basic_string(_InputIterator __beg, _InputIterator __end,
const _Alloc& __a = _Alloc())
: _M_dataplus(_S_construct(__beg, __end, __a), __a)
{ }
#ifdef __glibcxx_string_view // >= C++17
/**
* @brief Construct string from a substring of a string_view.
* @param __t Source object convertible to string view.
* @param __pos The index of the first character to copy from __t.
* @param __n The number of characters to copy from __t.
* @param __a Allocator to use.
*/
template<typename _Tp,
typename = enable_if_t<is_convertible_v<const _Tp&, __sv_type>>>
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) { }
#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.
*/
basic_string&
operator=(basic_string&& __str)
_GLIBCXX_NOEXCEPT_IF(allocator_traits<_Alloc>::is_always_equal::value)
{
// 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
#ifdef __glibcxx_string_view // >= C++17
/**
* @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
{
#if _GLIBCXX_FULLY_DYNAMIC_STRING == 0 && __OPTIMIZE__
if (_S_empty_rep()._M_length != 0)
__builtin_unreachable();
#endif
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 size(); }
/// 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
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
/// A non-binding request to reduce capacity() to size().
void
shrink_to_fit() noexcept
{ reserve(); }
#pragma GCC diagnostic pop
#endif
#ifdef __glibcxx_string_resize_and_overwrite // C++ >= 23
/** Resize the string and call a function to fill it.
*
* @param __n The maximum size requested.
* @param __op A callable object that writes characters to the string.
*
* This is a low-level function that is easy to misuse, be careful.
*
* Calling `str.resize_and_overwrite(n, op)` will reserve at least `n`
* characters in `str`, evaluate `n2 = std::move(op)(str.data(), n)`,
* and finally set the string length to `n2` (adding a null terminator
* at the end). The function object `op` is allowed to write to the
* extra capacity added by the initial reserve operation, which is not
* allowed if you just call `str.reserve(n)` yourself.
*
* This can be used to efficiently fill a `string` buffer without the
* overhead of zero-initializing characters that will be overwritten
* anyway.
*
* The callable `op` must not access the string directly (only through
* the pointer passed as its first argument), must not write more than
* `n` characters to the string, must return a value no greater than `n`,
* and must ensure that all characters up to the returned length are
* valid after it returns (i.e. there must be no uninitialized values
* left in the string after the call, because accessing them would
* have undefined behaviour). If `op` exits by throwing an exception
* the behaviour is undefined.
*
* @since C++23
*/
template<typename _Operation>
void
resize_and_overwrite(size_type __n, _Operation __op);
#endif // __glibcxx_string_resize_and_overwrite
#if __cplusplus >= 201103L
/// Non-standard version of resize_and_overwrite for C++11 and above.
template<typename _Operation>
void
__resize_and_overwrite(size_type __n, _Operation __op);
#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);
/// Equivalent to shrink_to_fit().
#if __cplusplus >= 202002L
[[deprecated("use shrink_to_fit() instead")]]
#endif
void
reserve();
/**
* 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>.
*/
_GLIBCXX_NODISCARD 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
#ifdef __glibcxx_string_view // >= C++17
/**
* @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 __glibcxx_containers_ranges // C++ >= 23
/**
* @brief Append a range to the string.
* @since C++23
*/
template<__detail::__container_compatible_range<_CharT> _Rg>
basic_string&
append_range(_Rg&& __rg)
{
basic_string __s(from_range, std::forward<_Rg>(__rg),
get_allocator());
append(__s);
return *this;
}
#endif
#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); }
#ifdef __glibcxx_string_view // >= C++17
/**
* @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()
+ std::__sv_check(__sv.size(), __pos, "basic_string::append"),
std::__sv_limit(__sv.size(), __pos, __n));
}
// _GLIBCXX_RESOLVE_LIB_DEFECTS
// 3662. basic_string::append/assign(NTBS, pos, n) suboptimal
/**
* @brief Append a C substring.
* @param __s The C string to append.
* @param __pos The position in the C string to append from.
* @param __n The number of characters to append.
* @return Reference to this string.
*/
basic_string&
append(const _CharT* __s, size_type __pos, size_type __n)
{ return append(__sv_type(__s).substr(__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.
*/
basic_string&
assign(basic_string&& __str)
noexcept(allocator_traits<_Alloc>::is_always_equal::value)
{
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 __glibcxx_containers_ranges // C++ >= 23
/**
* @brief Set value to a range of characters.
* @since C++23
*/
template<__detail::__container_compatible_range<_CharT> _Rg>
basic_string&
assign_range(_Rg&& __rg)
{
basic_string __s(from_range, std::forward<_Rg>(__rg),
get_allocator());
assign(std::move(__s));
return *this;
}
#endif
#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
#ifdef __glibcxx_string_view // >= C++17
/**
* @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()
+ std::__sv_check(__sv.size(), __pos, "basic_string::assign"),
std::__sv_limit(__sv.size(), __pos, __n));
}
// _GLIBCXX_RESOLVE_LIB_DEFECTS
// 3662. basic_string::append/assign(NTBS, pos, n) suboptimal
/**
* @brief Set value to a C substring.
* @param __s The C string to use.
* @param __pos The position in the C string to assign from.
* @param __n Number of characters to use.
* @return Reference to this string.
*/
basic_string&
assign(const _CharT* __s, size_type __pos, size_type __n)
{ return assign(__sv_type(__s).substr(__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 __glibcxx_containers_ranges // C++ >= 23
/**
* @brief Insert a range into the string.
* @since C++23
*/
template<__detail::__container_compatible_range<_CharT> _Rg>
iterator
insert_range(const_iterator __p, _Rg&& __rg)
{
auto __pos = __p - cbegin();
if constexpr (ranges::forward_range<_Rg>)
if (ranges::empty(__rg))
return begin() + __pos;
if (__p == cend())
append_range(std::forward<_Rg>(__rg));
else
{
basic_string __s(from_range, std::forward<_Rg>(__rg),
get_allocator());
insert(__pos, __s);
}
return begin() + __pos;
}
#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 >= _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 Position 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 Position 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 Position 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 Position 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);
}
#ifdef __glibcxx_string_view // >= C++17
/**
* @brief Insert a string_view.
* @param __pos 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 __pos1 Position in string to insert at.
* @param __svt The object convertible to string_view to insert from.
* @param __pos2 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()
+ std::__sv_check(__sv.size(), __pos2, "basic_string::insert"),
std::__sv_limit(__sv.size(), __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());
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 __glibcxx_containers_ranges // C++ >= 23
/**
* @brief Replace part of the string with a range.
* @since C++23
*/
template<__detail::__container_compatible_range<_CharT> _Rg>
basic_string&
replace_with_range(const_iterator __i1, const_iterator __i2, _Rg&& __rg)
{
if (__i1 == cend())
append_range(std::forward<_Rg>(__rg));
else
{
basic_string __s(from_range, std::forward<_Rg>(__rg),
get_allocator());
replace(__i1 - cbegin(), __i2 - __i1, __s);
}
return *this;
}
#endif
#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
#ifdef __glibcxx_string_view // >= C++17
/**
* @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()
+ std::__sv_check(__sv.size(), __pos2, "basic_string::replace"),
std::__sv_limit(__sv.size(), __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.
*/
void
swap(basic_string& __s)
_GLIBCXX_NOEXCEPT_IF(allocator_traits<_Alloc>::is_always_equal::value);
// 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 >= 201703L
/**
* @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.
*
* The standard requires this function to be `noexcept` but for the
* Copy-On-Write string implementation it can throw. This function
* allows modifying the string contents directly, which means we
* must copy-on-write to unshare it, which requires allocating memory.
*/
_CharT*
data() noexcept(false)
{
_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;
#ifdef __glibcxx_string_view // >= C++17
/**
* @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;
#ifdef __glibcxx_string_view // >= C++17
/**
* @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); }
#ifdef __glibcxx_string_view // >= C++17
/**
* @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); }
#ifdef __glibcxx_string_view // >= C++17
/**
* @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;
#ifdef __glibcxx_string_view // >= C++17
/**
* @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;
#ifdef __glibcxx_string_view // >= C++17
/**
* @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); }
#ifdef __glibcxx_string_subview // >= C++26
/**
* @brief Get a subview.
* @param __pos Index of first character (default 0).
* @param __n Number of characters in subview (default remainder).
* @return The subview.
* @throw std::out_of_range If __pos > size().
*
* Construct and return a subview using the `__n` characters starting at
* `__pos`. If the string is too short, use the remainder of the
* characters. If `__pos` is beyond the end of the string, out_of_range
* is thrown.
*/
[[nodiscard]]
constexpr basic_string_view<_CharT, _Traits>
subview(size_type __pos = 0, size_type __n = npos) const
{ return __sv_type(*this).subview(__pos, __n); }
#endif
/**
* @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;
}
#ifdef __glibcxx_string_view // >= C++17
/**
* @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
{
__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
{
__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
{
_M_check(__pos, "basic_string::compare");
__n = _M_limit(__pos, __n);
const size_type __osize = __str.size();
const size_type __len = std::min(__n, __osize);
int __r = traits_type::compare(_M_data() + __pos, __str.data(), __len);
if (!__r)
__r = _S_compare(__n, __osize);
return __r;
}
/**
* @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
{
_M_check(__pos1, "basic_string::compare");
__str._M_check(__pos2, "basic_string::compare");
__n1 = _M_limit(__pos1, __n1);
__n2 = __str._M_limit(__pos2, __n2);
const size_type __len = std::min(__n1, __n2);
int __r = traits_type::compare(_M_data() + __pos1,
__str.data() + __pos2, __len);
if (!__r)
__r = _S_compare(__n1, __n2);
return __r;
}
/**
* @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_requires_string(__s);
const size_type __size = this->size();
const size_type __osize = traits_type::length(__s);
const size_type __len = std::min(__size, __osize);
int __r = traits_type::compare(_M_data(), __s, __len);
if (!__r)
__r = _S_compare(__size, __osize);
return __r;
}
// _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
{
__glibcxx_requires_string(__s);
_M_check(__pos, "basic_string::compare");
__n1 = _M_limit(__pos, __n1);
const size_type __osize = traits_type::length(__s);
const size_type __len = std::min(__n1, __osize);
int __r = traits_type::compare(_M_data() + __pos, __s, __len);
if (!__r)
__r = _S_compare(__n1, __osize);
return __r;
}
/**
* @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
{
__glibcxx_requires_string_len(__s, __n2);
_M_check(__pos, "basic_string::compare");
__n1 = _M_limit(__pos, __n1);
const size_type __len = std::min(__n1, __n2);
int __r = traits_type::compare(_M_data() + __pos, __s, __len);
if (!__r)
__r = _S_compare(__n1, __n2);
return __r;
}
#if __cplusplus >= 202002L
bool
starts_with(basic_string_view<_CharT, _Traits> __x) const noexcept
{ return __sv_type(this->data(), this->size()).starts_with(__x); }
bool
starts_with(_CharT __x) const noexcept
{ return __sv_type(this->data(), this->size()).starts_with(__x); }
[[__gnu__::__nonnull__]]
bool
starts_with(const _CharT* __x) const noexcept
{ return __sv_type(this->data(), this->size()).starts_with(__x); }
bool
ends_with(basic_string_view<_CharT, _Traits> __x) const noexcept
{ return __sv_type(this->data(), this->size()).ends_with(__x); }
bool
ends_with(_CharT __x) const noexcept
{ return __sv_type(this->data(), this->size()).ends_with(__x); }
[[__gnu__::__nonnull__]]
bool
ends_with(const _CharT* __x) const noexcept
{ return __sv_type(this->data(), this->size()).ends_with(__x); }
#endif // C++20
#if __cplusplus > 202011L
bool
contains(basic_string_view<_CharT, _Traits> __x) const noexcept
{ return __sv_type(this->data(), this->size()).contains(__x); }
bool
contains(_CharT __x) const noexcept
{ return __sv_type(this->data(), this->size()).contains(__x); }
[[__gnu__::__nonnull__]]
bool
contains(const _CharT* __x) const noexcept
{ return __sv_type(this->data(), this->size()).contains(__x); }
#endif // C++23
# 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
};
template<typename _CharT, typename _Traits, typename _Alloc>
const typename basic_string<_CharT, _Traits, _Alloc>::size_type
basic_string<_CharT, _Traits, _Alloc>::
_Rep::_S_max_size = (((npos - sizeof(_Rep_base))/sizeof(_CharT)) - 1) / 4;
template<typename _CharT, typename _Traits, typename _Alloc>
const _CharT
basic_string<_CharT, _Traits, _Alloc>::
_Rep::_S_terminal = _CharT();
template<typename _CharT, typename _Traits, typename _Alloc>
const typename basic_string<_CharT, _Traits, _Alloc>::size_type
basic_string<_CharT, _Traits, _Alloc>::npos;
// Linker sets _S_empty_rep_storage to all 0s (one reference, empty string)
// at static init time (before static ctors are run).
template<typename _CharT, typename _Traits, typename _Alloc>
typename basic_string<_CharT, _Traits, _Alloc>::size_type
basic_string<_CharT, _Traits, _Alloc>::_Rep::_S_empty_rep_storage[
(sizeof(_Rep_base) + sizeof(_CharT) + sizeof(size_type) - 1) /
sizeof(size_type)];
// NB: This is the special case for Input Iterators, used in
// istreambuf_iterators, etc.
// Input Iterators have a cost structure very different from
// pointers, calling for a different coding style.
template<typename _CharT, typename _Traits, typename _Alloc>
template<typename _InIterator>
_CharT*
basic_string<_CharT, _Traits, _Alloc>::
_S_construct(_InIterator __beg, _InIterator __end, const _Alloc& __a,
input_iterator_tag)
{
#if _GLIBCXX_FULLY_DYNAMIC_STRING == 0
if (__beg == __end && __a == _Alloc())
return _S_empty_rep()._M_refdata();
#endif
// Avoid reallocation for common case.
_CharT __buf[128];
size_type __len = 0;
while (__beg != __end && __len < sizeof(__buf) / sizeof(_CharT))
{
__buf[__len++] = *__beg;
++__beg;
}
_Rep* __r = _Rep::_S_create(__len, size_type(0), __a);
_M_copy(__r->_M_refdata(), __buf, __len);
__try
{
while (__beg != __end)
{
if (__len == __r->_M_capacity)
{
// Allocate more space.
_Rep* __another = _Rep::_S_create(__len + 1, __len, __a);
_M_copy(__another->_M_refdata(), __r->_M_refdata(), __len);
__r->_M_destroy(__a);
__r = __another;
}
__r->_M_refdata()[__len++] = *__beg;
++__beg;
}
}
__catch(...)
{
__r->_M_destroy(__a);
__throw_exception_again;
}
__r->_M_set_length_and_sharable(__len);
return __r->_M_refdata();
}
template<typename _CharT, typename _Traits, typename _Alloc>
template <typename _InIterator>
_CharT*
basic_string<_CharT, _Traits, _Alloc>::
_S_construct(_InIterator __beg, _InIterator __end, const _Alloc& __a,
forward_iterator_tag)
{
#if _GLIBCXX_FULLY_DYNAMIC_STRING == 0
if (__beg == __end && __a == _Alloc())
return _S_empty_rep()._M_refdata();
#endif
// NB: Not required, but considered best practice.
if (__gnu_cxx::__is_null_pointer(__beg) && __beg != __end)
__throw_logic_error(__N("basic_string::_S_construct null not valid"));
const size_type __dnew = static_cast<size_type>(std::distance(__beg,
__end));
// Check for out_of_range and length_error exceptions.
_Rep* __r = _Rep::_S_create(__dnew, size_type(0), __a);
__try
{ _S_copy_chars(__r->_M_refdata(), __beg, __end); }
__catch(...)
{
__r->_M_destroy(__a);
__throw_exception_again;
}
__r->_M_set_length_and_sharable(__dnew);
return __r->_M_refdata();
}
template<typename _CharT, typename _Traits, typename _Alloc>
_CharT*
basic_string<_CharT, _Traits, _Alloc>::
_S_construct(size_type __n, _CharT __c, const _Alloc& __a)
{
#if _GLIBCXX_FULLY_DYNAMIC_STRING == 0
if (__n == 0 && __a == _Alloc())
return _S_empty_rep()._M_refdata();
#endif
// Check for out_of_range and length_error exceptions.
_Rep* __r = _Rep::_S_create(__n, size_type(0), __a);
if (__n)
_M_assign(__r->_M_refdata(), __n, __c);
__r->_M_set_length_and_sharable(__n);
return __r->_M_refdata();
}
template<typename _CharT, typename _Traits, typename _Alloc>
basic_string<_CharT, _Traits, _Alloc>::
basic_string(const basic_string& __str, size_type __pos, const _Alloc& __a)
: _M_dataplus(_S_construct(__str._M_data()
+ __str._M_check(__pos,
"basic_string::basic_string"),
__str._M_data() + __str._M_limit(__pos, npos)
+ __pos, __a), __a)
{ }
template<typename _CharT, typename _Traits, typename _Alloc>
basic_string<_CharT, _Traits, _Alloc>::
basic_string(const basic_string& __str, size_type __pos, size_type __n)
: _M_dataplus(_S_construct(__str._M_data()
+ __str._M_check(__pos,
"basic_string::basic_string"),
__str._M_data() + __str._M_limit(__pos, __n)
+ __pos, _Alloc()), _Alloc())
{ }
template<typename _CharT, typename _Traits, typename _Alloc>
basic_string<_CharT, _Traits, _Alloc>::
basic_string(const basic_string& __str, size_type __pos,
size_type __n, const _Alloc& __a)
: _M_dataplus(_S_construct(__str._M_data()
+ __str._M_check(__pos,
"basic_string::basic_string"),
__str._M_data() + __str._M_limit(__pos, __n)
+ __pos, __a), __a)
{ }
template<typename _CharT, typename _Traits, typename _Alloc>
basic_string<_CharT, _Traits, _Alloc>&
basic_string<_CharT, _Traits, _Alloc>::
assign(const basic_string& __str)
{
if (_M_rep() != __str._M_rep())
{
// XXX MT
const allocator_type __a = this->get_allocator();
_CharT* __tmp = __str._M_rep()->_M_grab(__a, __str.get_allocator());
_M_rep()->_M_dispose(__a);
_M_data(__tmp);
}
return *this;
}
template<typename _CharT, typename _Traits, typename _Alloc>
basic_string<_CharT, _Traits, _Alloc>&
basic_string<_CharT, _Traits, _Alloc>::
assign(const _CharT* __s, size_type __n)
{
__glibcxx_requires_string_len(__s, __n);
_M_check_length(this->size(), __n, "basic_string::assign");
if (_M_disjunct(__s) || _M_rep()->_M_is_shared())
return _M_replace_safe(size_type(0), this->size(), __s, __n);
else
{
// Work in-place.
const size_type __pos = __s - _M_data();
if (__pos >= __n)
_M_copy(_M_data(), __s, __n);
else if (__pos)
_M_move(_M_data(), __s, __n);
_M_rep()->_M_set_length_and_sharable(__n);
return *this;
}
}
template<typename _CharT, typename _Traits, typename _Alloc>
basic_string<_CharT, _Traits, _Alloc>&
basic_string<_CharT, _Traits, _Alloc>::
append(size_type __n, _CharT __c)
{
if (__n)
{
_M_check_length(size_type(0), __n, "basic_string::append");
const size_type __len = __n + this->size();
if (__len > this->capacity() || _M_rep()->_M_is_shared())
this->reserve(__len);
_M_assign(_M_data() + this->size(), __n, __c);
_M_rep()->_M_set_length_and_sharable(__len);
}
return *this;
}
template<typename _CharT, typename _Traits, typename _Alloc>
basic_string<_CharT, _Traits, _Alloc>&
basic_string<_CharT, _Traits, _Alloc>::
append(const _CharT* __s, size_type __n)
{
__glibcxx_requires_string_len(__s, __n);
if (__n)
{
_M_check_length(size_type(0), __n, "basic_string::append");
const size_type __len = __n + this->size();
if (__len > this->capacity() || _M_rep()->_M_is_shared())
{
if (_M_disjunct(__s))
this->reserve(__len);
else
{
const size_type __off = __s - _M_data();
this->reserve(__len);
__s = _M_data() + __off;
}
}
_M_copy(_M_data() + this->size(), __s, __n);
_M_rep()->_M_set_length_and_sharable(__len);
}
return *this;
}
template<typename _CharT, typename _Traits, typename _Alloc>
basic_string<_CharT, _Traits, _Alloc>&
basic_string<_CharT, _Traits, _Alloc>::
append(const basic_string& __str)
{
const size_type __size = __str.size();
if (__size)
{
const size_type __len = __size + this->size();
if (__len > this->capacity() || _M_rep()->_M_is_shared())
this->reserve(__len);
_M_copy(_M_data() + this->size(), __str._M_data(), __size);
_M_rep()->_M_set_length_and_sharable(__len);
}
return *this;
}
template<typename _CharT, typename _Traits, typename _Alloc>
basic_string<_CharT, _Traits, _Alloc>&
basic_string<_CharT, _Traits, _Alloc>::
append(const basic_string& __str, size_type __pos, size_type __n)
{
__str._M_check(__pos, "basic_string::append");
__n = __str._M_limit(__pos, __n);
if (__n)
{
const size_type __len = __n + this->size();
if (__len > this->capacity() || _M_rep()->_M_is_shared())
this->reserve(__len);
_M_copy(_M_data() + this->size(), __str._M_data() + __pos, __n);
_M_rep()->_M_set_length_and_sharable(__len);
}
return *this;
}
template<typename _CharT, typename _Traits, typename _Alloc>
basic_string<_CharT, _Traits, _Alloc>&
basic_string<_CharT, _Traits, _Alloc>::
insert(size_type __pos, const _CharT* __s, size_type __n)
{
__glibcxx_requires_string_len(__s, __n);
_M_check(__pos, "basic_string::insert");
_M_check_length(size_type(0), __n, "basic_string::insert");
if (_M_disjunct(__s) || _M_rep()->_M_is_shared())
return _M_replace_safe(__pos, size_type(0), __s, __n);
else
{
// Work in-place.
const size_type __off = __s - _M_data();
_M_mutate(__pos, 0, __n);
__s = _M_data() + __off;
_CharT* __p = _M_data() + __pos;
if (__s + __n <= __p)
_M_copy(__p, __s, __n);
else if (__s >= __p)
_M_copy(__p, __s + __n, __n);
else
{
const size_type __nleft = __p - __s;
_M_copy(__p, __s, __nleft);
_M_copy(__p + __nleft, __p + __n, __n - __nleft);
}
return *this;
}
}
template<typename _CharT, typename _Traits, typename _Alloc>
typename basic_string<_CharT, _Traits, _Alloc>::iterator
basic_string<_CharT, _Traits, _Alloc>::
erase(iterator __first, iterator __last)
{
_GLIBCXX_DEBUG_PEDASSERT(__first >= _M_ibegin() && __first <= __last
&& __last <= _M_iend());
// NB: This isn't just an optimization (bail out early when
// there is nothing to do, really), it's also a correctness
// issue vs MT, see libstdc++/40518.
const size_type __size = __last - __first;
if (__size)
{
const size_type __pos = __first - _M_ibegin();
_M_mutate(__pos, __size, size_type(0));
_M_rep()->_M_set_leaked();
return iterator(_M_data() + __pos);
}
else
return __first;
}
template<typename _CharT, typename _Traits, typename _Alloc>
basic_string<_CharT, _Traits, _Alloc>&
basic_string<_CharT, _Traits, _Alloc>::
replace(size_type __pos, size_type __n1, const _CharT* __s,
size_type __n2)
{
__glibcxx_requires_string_len(__s, __n2);
_M_check(__pos, "basic_string::replace");
__n1 = _M_limit(__pos, __n1);
_M_check_length(__n1, __n2, "basic_string::replace");
bool __left;
if (_M_disjunct(__s) || _M_rep()->_M_is_shared())
return _M_replace_safe(__pos, __n1, __s, __n2);
else if ((__left = __s + __n2 <= _M_data() + __pos)
|| _M_data() + __pos + __n1 <= __s)
{
// Work in-place: non-overlapping case.
size_type __off = __s - _M_data();
__left ? __off : (__off += __n2 - __n1);
_M_mutate(__pos, __n1, __n2);
_M_copy(_M_data() + __pos, _M_data() + __off, __n2);
return *this;
}
else
{
// TODO: overlapping case.
const basic_string __tmp(__s, __n2);
return _M_replace_safe(__pos, __n1, __tmp._M_data(), __n2);
}
}
template<typename _CharT, typename _Traits, typename _Alloc>
void
basic_string<_CharT, _Traits, _Alloc>::_Rep::
_M_destroy(const _Alloc& __a) throw ()
{
const size_type __size = sizeof(_Rep_base)
+ (this->_M_capacity + 1) * sizeof(_CharT);
_Raw_bytes_alloc(__a).deallocate(reinterpret_cast<char*>(this), __size);
}
template<typename _CharT, typename _Traits, typename _Alloc>
void
basic_string<_CharT, _Traits, _Alloc>::
_M_leak_hard()
{
// No need to create a new copy of an empty string when a non-const
// reference/pointer/iterator into it is obtained. Modifying the
// trailing null character is undefined, so the ref/pointer/iterator
// is effectively const anyway.
if (this->empty())
return;
if (_M_rep()->_M_is_shared())
_M_mutate(0, 0, 0);
_M_rep()->_M_set_leaked();
}
template<typename _CharT, typename _Traits, typename _Alloc>
void
basic_string<_CharT, _Traits, _Alloc>::
_M_mutate(size_type __pos, size_type __len1, size_type __len2)
{
const size_type __old_size = this->size();
const size_type __new_size = __old_size + __len2 - __len1;
const size_type __how_much = __old_size - __pos - __len1;
if (__new_size > this->capacity() || _M_rep()->_M_is_shared())
{
// Must reallocate.
const allocator_type __a = get_allocator();
_Rep* __r = _Rep::_S_create(__new_size, this->capacity(), __a);
if (__pos)
_M_copy(__r->_M_refdata(), _M_data(), __pos);
if (__how_much)
_M_copy(__r->_M_refdata() + __pos + __len2,
_M_data() + __pos + __len1, __how_much);
_M_rep()->_M_dispose(__a);
_M_data(__r->_M_refdata());
}
else if (__how_much && __len1 != __len2)
{
// Work in-place.
_M_move(_M_data() + __pos + __len2,
_M_data() + __pos + __len1, __how_much);
}
_M_rep()->_M_set_length_and_sharable(__new_size);
}
template<typename _CharT, typename _Traits, typename _Alloc>
void
basic_string<_CharT, _Traits, _Alloc>::
reserve(size_type __res)
{
const size_type __capacity = capacity();
// _GLIBCXX_RESOLVE_LIB_DEFECTS
// 2968. Inconsistencies between basic_string reserve and
// vector/unordered_map/unordered_set reserve functions
// P0966 reserve should not shrink
if (__res <= __capacity)
{
if (!_M_rep()->_M_is_shared())
return;
// unshare, but keep same capacity
__res = __capacity;
}
const allocator_type __a = get_allocator();
_CharT* __tmp = _M_rep()->_M_clone(__a, __res - this->size());
_M_rep()->_M_dispose(__a);
_M_data(__tmp);
}
template<typename _CharT, typename _Traits, typename _Alloc>
void
basic_string<_CharT, _Traits, _Alloc>::
swap(basic_string& __s)
_GLIBCXX_NOEXCEPT_IF(allocator_traits<_Alloc>::is_always_equal::value)
{
if (_M_rep()->_M_is_leaked())
_M_rep()->_M_set_sharable();
if (__s._M_rep()->_M_is_leaked())
__s._M_rep()->_M_set_sharable();
if (this->get_allocator() == __s.get_allocator())
{
_CharT* __tmp = _M_data();
_M_data(__s._M_data());
__s._M_data(__tmp);
}
// The code below can usually be optimized away.
else
{
const basic_string __tmp1(_M_ibegin(), _M_iend(),
__s.get_allocator());
const basic_string __tmp2(__s._M_ibegin(), __s._M_iend(),
this->get_allocator());
*this = __tmp2;
__s = __tmp1;
}
}
template<typename _CharT, typename _Traits, typename _Alloc>
typename basic_string<_CharT, _Traits, _Alloc>::_Rep*
basic_string<_CharT, _Traits, _Alloc>::_Rep::
_S_create(size_type __capacity, size_type __old_capacity,
const _Alloc& __alloc)
{
// _GLIBCXX_RESOLVE_LIB_DEFECTS
// 83. String::npos vs. string::max_size()
if (__capacity > _S_max_size)
__throw_length_error(__N("basic_string::_S_create"));
// The standard places no restriction on allocating more memory
// than is strictly needed within this layer at the moment or as
// requested by an explicit application call to reserve(n).
// Many malloc implementations perform quite poorly when an
// application attempts to allocate memory in a stepwise fashion
// growing each allocation size by only 1 char. Additionally,
// it makes little sense to allocate less linear memory than the
// natural blocking size of the malloc implementation.
// Unfortunately, we would need a somewhat low-level calculation
// with tuned parameters to get this perfect for any particular
// malloc implementation. Fortunately, generalizations about
// common features seen among implementations seems to suffice.
// __pagesize need not match the actual VM page size for good
// results in practice, thus we pick a common value on the low
// side. __malloc_header_size is an estimate of the amount of
// overhead per memory allocation (in practice seen N * sizeof
// (void*) where N is 0, 2 or 4). According to folklore,
// picking this value on the high side is better than
// low-balling it (especially when this algorithm is used with
// malloc implementations that allocate memory blocks rounded up
// to a size which is a power of 2).
const size_type __pagesize = 4096;
const size_type __malloc_header_size = 4 * sizeof(void*);
// The below implements an exponential growth policy, necessary to
// meet amortized linear time requirements of the library: see
// http://gcc.gnu.org/ml/libstdc++/2001-07/msg00085.html.
// It's active for allocations requiring an amount of memory above
// system pagesize. This is consistent with the requirements of the
// standard: http://gcc.gnu.org/ml/libstdc++/2001-07/msg00130.html
if (__capacity > __old_capacity && __capacity < 2 * __old_capacity)
__capacity = 2 * __old_capacity;
// NB: Need an array of char_type[__capacity], plus a terminating
// null char_type() element, plus enough for the _Rep data structure.
// Whew. Seemingly so needy, yet so elemental.
size_type __size = (__capacity + 1) * sizeof(_CharT) + sizeof(_Rep);
const size_type __adj_size = __size + __malloc_header_size;
if (__adj_size > __pagesize && __capacity > __old_capacity)
{
const size_type __extra = __pagesize - __adj_size % __pagesize;
__capacity += __extra / sizeof(_CharT);
// Never allocate a string bigger than _S_max_size.
if (__capacity > _S_max_size)
__capacity = _S_max_size;
__size = (__capacity + 1) * sizeof(_CharT) + sizeof(_Rep);
}
// NB: Might throw, but no worries about a leak, mate: _Rep()
// does not throw.
void* __place = _Raw_bytes_alloc(__alloc).allocate(__size);
_Rep *__p = new (__place) _Rep;
__p->_M_capacity = __capacity;
// ABI compatibility - 3.4.x set in _S_create both
// _M_refcount and _M_length. All callers of _S_create
// in basic_string.tcc then set just _M_length.
// In 4.0.x and later both _M_refcount and _M_length
// are initialized in the callers, unfortunately we can
// have 3.4.x compiled code with _S_create callers inlined
// calling 4.0.x+ _S_create.
__p->_M_set_sharable();
return __p;
}
template<typename _CharT, typename _Traits, typename _Alloc>
_CharT*
basic_string<_CharT, _Traits, _Alloc>::_Rep::
_M_clone(const _Alloc& __alloc, size_type __res)
{
// Requested capacity of the clone.
const size_type __requested_cap = this->_M_length + __res;
_Rep* __r = _Rep::_S_create(__requested_cap, this->_M_capacity,
__alloc);
if (this->_M_length)
_M_copy(__r->_M_refdata(), _M_refdata(), this->_M_length);
__r->_M_set_length_and_sharable(this->_M_length);
return __r->_M_refdata();
}
template<typename _CharT, typename _Traits, typename _Alloc>
void
basic_string<_CharT, _Traits, _Alloc>::
resize(size_type __n, _CharT __c)
{
const size_type __size = this->size();
_M_check_length(__size, __n, "basic_string::resize");
if (__size < __n)
this->append(__n - __size, __c);
else if (__n < __size)
this->erase(__n);
// else nothing (in particular, avoid calling _M_mutate() unnecessarily.)
}
template<typename _CharT, typename _Traits, typename _Alloc>
template<typename _InputIterator>
basic_string<_CharT, _Traits, _Alloc>&
basic_string<_CharT, _Traits, _Alloc>::
_M_replace_dispatch(iterator __i1, iterator __i2, _InputIterator __k1,
_InputIterator __k2, __false_type)
{
__glibcxx_requires_valid_range(__k1, __k2);
const basic_string __s(__k1, __k2);
const size_type __n1 = __i2 - __i1;
_M_check_length(__n1, __s.size(), "basic_string::_M_replace_dispatch");
return _M_replace_safe(__i1 - _M_ibegin(), __n1, __s._M_data(),
__s.size());
}
template<typename _CharT, typename _Traits, typename _Alloc>
basic_string<_CharT, _Traits, _Alloc>&
basic_string<_CharT, _Traits, _Alloc>::
_M_replace_aux(size_type __pos1, size_type __n1, size_type __n2,
_CharT __c)
{
_M_check_length(__n1, __n2, "basic_string::_M_replace_aux");
_M_mutate(__pos1, __n1, __n2);
if (__n2)
_M_assign(_M_data() + __pos1, __n2, __c);
return *this;
}
template<typename _CharT, typename _Traits, typename _Alloc>
basic_string<_CharT, _Traits, _Alloc>&
basic_string<_CharT, _Traits, _Alloc>::
_M_replace_safe(size_type __pos1, size_type __n1, const _CharT* __s,
size_type __n2)
{
_M_mutate(__pos1, __n1, __n2);
if (__n2)
_M_copy(_M_data() + __pos1, __s, __n2);
return *this;
}
template<typename _CharT, typename _Traits, typename _Alloc>
void
basic_string<_CharT, _Traits, _Alloc>::
reserve()
{
#if __cpp_exceptions
if (length() < capacity() || _M_rep()->_M_is_shared())
try
{
const allocator_type __a = get_allocator();
_CharT* __tmp = _M_rep()->_M_clone(__a);
_M_rep()->_M_dispose(__a);
_M_data(__tmp);
}
catch (const __cxxabiv1::__forced_unwind&)
{ throw; }
catch (...)
{ /* swallow the exception */ }
#endif
}
template<typename _CharT, typename _Traits, typename _Alloc>
typename basic_string<_CharT, _Traits, _Alloc>::size_type
basic_string<_CharT, _Traits, _Alloc>::
copy(_CharT* __s, size_type __n, size_type __pos) const
{
_M_check(__pos, "basic_string::copy");
__n = _M_limit(__pos, __n);
__glibcxx_requires_string_len(__s, __n);
if (__n)
_M_copy(__s, _M_data() + __pos, __n);
// 21.3.5.7 par 3: do not append null. (good.)
return __n;
}
#ifdef __glibcxx_string_resize_and_overwrite // C++ >= 23
template<typename _CharT, typename _Traits, typename _Alloc>
template<typename _Operation>
[[__gnu__::__always_inline__]]
inline void
basic_string<_CharT, _Traits, _Alloc>::
__resize_and_overwrite(const size_type __n, _Operation __op)
{ resize_and_overwrite<_Operation&>(__n, __op); }
#endif
#if __cplusplus >= 201103L
template<typename _CharT, typename _Traits, typename _Alloc>
template<typename _Operation>
void
basic_string<_CharT, _Traits, _Alloc>::
#ifdef __glibcxx_string_resize_and_overwrite // C++ >= 23
resize_and_overwrite(const size_type __n, _Operation __op)
#else
__resize_and_overwrite(const size_type __n, _Operation __op)
#endif
{
const size_type __capacity = capacity();
_CharT* __p;
if (__n > __capacity || _M_rep()->_M_is_shared())
this->reserve(__n);
__p = _M_data();
struct _Terminator {
~_Terminator() { _M_this->_M_rep()->_M_set_length_and_sharable(_M_r); }
basic_string* _M_this;
size_type _M_r;
};
_Terminator __term{this, 0};
auto __r = std::move(__op)(__p + 0, __n + 0);
#ifdef __cpp_lib_concepts
static_assert(ranges::__detail::__is_integer_like<decltype(__r)>);
#else
static_assert(__gnu_cxx::__is_integer_nonstrict<decltype(__r)>::__value,
"resize_and_overwrite operation must return an integer");
#endif
_GLIBCXX_DEBUG_ASSERT(__r >= 0 && size_type(__r) <= __n);
__term._M_r = size_type(__r);
if (__term._M_r > __n)
__builtin_unreachable();
}
#endif // C++11
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std
#endif // ! _GLIBCXX_USE_CXX11_ABI
#endif // _COW_STRING_H