libstdc++
basic_string.h
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1 // Components for manipulating sequences of characters -*- C++ -*-
2 
3 // Copyright (C) 1997-2021 Free Software Foundation, Inc.
4 //
5 // This file is part of the GNU ISO C++ Library. This library is free
6 // software; you can redistribute it and/or modify it under the
7 // terms of the GNU General Public License as published by the
8 // Free Software Foundation; either version 3, or (at your option)
9 // any later version.
10 
11 // This library is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 // GNU General Public License for more details.
15 
16 // Under Section 7 of GPL version 3, you are granted additional
17 // permissions described in the GCC Runtime Library Exception, version
18 // 3.1, as published by the Free Software Foundation.
19 
20 // You should have received a copy of the GNU General Public License and
21 // a copy of the GCC Runtime Library Exception along with this program;
22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23 // <http://www.gnu.org/licenses/>.
24 
25 /** @file bits/basic_string.h
26  * This is an internal header file, included by other library headers.
27  * Do not attempt to use it directly. @headername{string}
28  */
29 
30 //
31 // ISO C++ 14882: 21 Strings library
32 //
33 
34 #ifndef _BASIC_STRING_H
35 #define _BASIC_STRING_H 1
36 
37 #pragma GCC system_header
38 
39 #include <ext/atomicity.h>
40 #include <ext/alloc_traits.h>
41 #include <debug/debug.h>
42 
43 #if __cplusplus >= 201103L
44 #include <initializer_list>
45 #endif
46 
47 #if __cplusplus >= 201703L
48 # include <string_view>
49 #endif
50 
51 
52 namespace std _GLIBCXX_VISIBILITY(default)
53 {
54 _GLIBCXX_BEGIN_NAMESPACE_VERSION
55 
56 #if _GLIBCXX_USE_CXX11_ABI
57 _GLIBCXX_BEGIN_NAMESPACE_CXX11
58  /**
59  * @class basic_string basic_string.h <string>
60  * @brief Managing sequences of characters and character-like objects.
61  *
62  * @ingroup strings
63  * @ingroup sequences
64  *
65  * @tparam _CharT Type of character
66  * @tparam _Traits Traits for character type, defaults to
67  * char_traits<_CharT>.
68  * @tparam _Alloc Allocator type, defaults to allocator<_CharT>.
69  *
70  * Meets the requirements of a <a href="tables.html#65">container</a>, a
71  * <a href="tables.html#66">reversible container</a>, and a
72  * <a href="tables.html#67">sequence</a>. Of the
73  * <a href="tables.html#68">optional sequence requirements</a>, only
74  * @c push_back, @c at, and @c %array access are supported.
75  */
76  template<typename _CharT, typename _Traits, typename _Alloc>
77  class basic_string
78  {
80  rebind<_CharT>::other _Char_alloc_type;
81  typedef __gnu_cxx::__alloc_traits<_Char_alloc_type> _Alloc_traits;
82 
83  // Types:
84  public:
85  typedef _Traits traits_type;
86  typedef typename _Traits::char_type value_type;
87  typedef _Char_alloc_type allocator_type;
88  typedef typename _Alloc_traits::size_type size_type;
89  typedef typename _Alloc_traits::difference_type difference_type;
90  typedef typename _Alloc_traits::reference reference;
91  typedef typename _Alloc_traits::const_reference const_reference;
92  typedef typename _Alloc_traits::pointer pointer;
93  typedef typename _Alloc_traits::const_pointer const_pointer;
94  typedef __gnu_cxx::__normal_iterator<pointer, basic_string> iterator;
95  typedef __gnu_cxx::__normal_iterator<const_pointer, basic_string>
96  const_iterator;
97  typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
98  typedef std::reverse_iterator<iterator> reverse_iterator;
99 
100  /// Value returned by various member functions when they fail.
101  static const size_type npos = static_cast<size_type>(-1);
102 
103  protected:
104  // type used for positions in insert, erase etc.
105 #if __cplusplus < 201103L
106  typedef iterator __const_iterator;
107 #else
108  typedef const_iterator __const_iterator;
109 #endif
110 
111  private:
112 #if __cplusplus >= 201703L
113  // A helper type for avoiding boiler-plate.
114  typedef basic_string_view<_CharT, _Traits> __sv_type;
115 
116  template<typename _Tp, typename _Res>
117  using _If_sv = enable_if_t<
118  __and_<is_convertible<const _Tp&, __sv_type>,
119  __not_<is_convertible<const _Tp*, const basic_string*>>,
120  __not_<is_convertible<const _Tp&, const _CharT*>>>::value,
121  _Res>;
122 
123  // Allows an implicit conversion to __sv_type.
124  static __sv_type
125  _S_to_string_view(__sv_type __svt) noexcept
126  { return __svt; }
127 
128  // Wraps a string_view by explicit conversion and thus
129  // allows to add an internal constructor that does not
130  // participate in overload resolution when a string_view
131  // is provided.
132  struct __sv_wrapper
133  {
134  explicit __sv_wrapper(__sv_type __sv) noexcept : _M_sv(__sv) { }
135  __sv_type _M_sv;
136  };
137 
138  /**
139  * @brief Only internally used: Construct string from a string view
140  * wrapper.
141  * @param __svw string view wrapper.
142  * @param __a Allocator to use.
143  */
144  explicit
145  basic_string(__sv_wrapper __svw, const _Alloc& __a)
146  : basic_string(__svw._M_sv.data(), __svw._M_sv.size(), __a) { }
147 #endif
148 
149  // Use empty-base optimization: http://www.cantrip.org/emptyopt.html
150  struct _Alloc_hider : allocator_type // TODO check __is_final
151  {
152 #if __cplusplus < 201103L
153  _Alloc_hider(pointer __dat, const _Alloc& __a = _Alloc())
154  : allocator_type(__a), _M_p(__dat) { }
155 #else
156  _Alloc_hider(pointer __dat, const _Alloc& __a)
157  : allocator_type(__a), _M_p(__dat) { }
158 
159  _Alloc_hider(pointer __dat, _Alloc&& __a = _Alloc())
160  : allocator_type(std::move(__a)), _M_p(__dat) { }
161 #endif
162 
163  pointer _M_p; // The actual data.
164  };
165 
166  _Alloc_hider _M_dataplus;
167  size_type _M_string_length;
168 
169  enum { _S_local_capacity = 15 / sizeof(_CharT) };
170 
171  union
172  {
173  _CharT _M_local_buf[_S_local_capacity + 1];
174  size_type _M_allocated_capacity;
175  };
176 
177  void
178  _M_data(pointer __p)
179  { _M_dataplus._M_p = __p; }
180 
181  void
182  _M_length(size_type __length)
183  { _M_string_length = __length; }
184 
185  pointer
186  _M_data() const
187  { return _M_dataplus._M_p; }
188 
189  pointer
190  _M_local_data()
191  {
192 #if __cplusplus >= 201103L
193  return std::pointer_traits<pointer>::pointer_to(*_M_local_buf);
194 #else
195  return pointer(_M_local_buf);
196 #endif
197  }
198 
199  const_pointer
200  _M_local_data() const
201  {
202 #if __cplusplus >= 201103L
204 #else
205  return const_pointer(_M_local_buf);
206 #endif
207  }
208 
209  void
210  _M_capacity(size_type __capacity)
211  { _M_allocated_capacity = __capacity; }
212 
213  void
214  _M_set_length(size_type __n)
215  {
216  _M_length(__n);
217  traits_type::assign(_M_data()[__n], _CharT());
218  }
219 
220  bool
221  _M_is_local() const
222  { return _M_data() == _M_local_data(); }
223 
224  // Create & Destroy
225  pointer
226  _M_create(size_type&, size_type);
227 
228  void
229  _M_dispose()
230  {
231  if (!_M_is_local())
232  _M_destroy(_M_allocated_capacity);
233  }
234 
235  void
236  _M_destroy(size_type __size) throw()
237  { _Alloc_traits::deallocate(_M_get_allocator(), _M_data(), __size + 1); }
238 
239  // _M_construct_aux is used to implement the 21.3.1 para 15 which
240  // requires special behaviour if _InIterator is an integral type
241  template<typename _InIterator>
242  void
243  _M_construct_aux(_InIterator __beg, _InIterator __end,
244  std::__false_type)
245  {
246  typedef typename iterator_traits<_InIterator>::iterator_category _Tag;
247  _M_construct(__beg, __end, _Tag());
248  }
249 
250  // _GLIBCXX_RESOLVE_LIB_DEFECTS
251  // 438. Ambiguity in the "do the right thing" clause
252  template<typename _Integer>
253  void
254  _M_construct_aux(_Integer __beg, _Integer __end, std::__true_type)
255  { _M_construct_aux_2(static_cast<size_type>(__beg), __end); }
256 
257  void
258  _M_construct_aux_2(size_type __req, _CharT __c)
259  { _M_construct(__req, __c); }
260 
261  template<typename _InIterator>
262  void
263  _M_construct(_InIterator __beg, _InIterator __end)
264  {
265  typedef typename std::__is_integer<_InIterator>::__type _Integral;
266  _M_construct_aux(__beg, __end, _Integral());
267  }
268 
269  // For Input Iterators, used in istreambuf_iterators, etc.
270  template<typename _InIterator>
271  void
272  _M_construct(_InIterator __beg, _InIterator __end,
274 
275  // For forward_iterators up to random_access_iterators, used for
276  // string::iterator, _CharT*, etc.
277  template<typename _FwdIterator>
278  void
279  _M_construct(_FwdIterator __beg, _FwdIterator __end,
281 
282  void
283  _M_construct(size_type __req, _CharT __c);
284 
285  allocator_type&
286  _M_get_allocator()
287  { return _M_dataplus; }
288 
289  const allocator_type&
290  _M_get_allocator() const
291  { return _M_dataplus; }
292 
293  private:
294 
295 #ifdef _GLIBCXX_DISAMBIGUATE_REPLACE_INST
296  // The explicit instantiations in misc-inst.cc require this due to
297  // https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64063
298  template<typename _Tp, bool _Requires =
299  !__are_same<_Tp, _CharT*>::__value
300  && !__are_same<_Tp, const _CharT*>::__value
301  && !__are_same<_Tp, iterator>::__value
302  && !__are_same<_Tp, const_iterator>::__value>
303  struct __enable_if_not_native_iterator
304  { typedef basic_string& __type; };
305  template<typename _Tp>
306  struct __enable_if_not_native_iterator<_Tp, false> { };
307 #endif
308 
309  size_type
310  _M_check(size_type __pos, const char* __s) const
311  {
312  if (__pos > this->size())
313  __throw_out_of_range_fmt(__N("%s: __pos (which is %zu) > "
314  "this->size() (which is %zu)"),
315  __s, __pos, this->size());
316  return __pos;
317  }
318 
319  void
320  _M_check_length(size_type __n1, size_type __n2, const char* __s) const
321  {
322  if (this->max_size() - (this->size() - __n1) < __n2)
323  __throw_length_error(__N(__s));
324  }
325 
326 
327  // NB: _M_limit doesn't check for a bad __pos value.
328  size_type
329  _M_limit(size_type __pos, size_type __off) const _GLIBCXX_NOEXCEPT
330  {
331  const bool __testoff = __off < this->size() - __pos;
332  return __testoff ? __off : this->size() - __pos;
333  }
334 
335  // True if _Rep and source do not overlap.
336  bool
337  _M_disjunct(const _CharT* __s) const _GLIBCXX_NOEXCEPT
338  {
339  return (less<const _CharT*>()(__s, _M_data())
340  || less<const _CharT*>()(_M_data() + this->size(), __s));
341  }
342 
343  // When __n = 1 way faster than the general multichar
344  // traits_type::copy/move/assign.
345  static void
346  _S_copy(_CharT* __d, const _CharT* __s, size_type __n)
347  {
348  if (__n == 1)
349  traits_type::assign(*__d, *__s);
350  else
351  traits_type::copy(__d, __s, __n);
352  }
353 
354  static void
355  _S_move(_CharT* __d, const _CharT* __s, size_type __n)
356  {
357  if (__n == 1)
358  traits_type::assign(*__d, *__s);
359  else
360  traits_type::move(__d, __s, __n);
361  }
362 
363  static void
364  _S_assign(_CharT* __d, size_type __n, _CharT __c)
365  {
366  if (__n == 1)
367  traits_type::assign(*__d, __c);
368  else
369  traits_type::assign(__d, __n, __c);
370  }
371 
372  // _S_copy_chars is a separate template to permit specialization
373  // to optimize for the common case of pointers as iterators.
374  template<class _Iterator>
375  static void
376  _S_copy_chars(_CharT* __p, _Iterator __k1, _Iterator __k2)
377  {
378  for (; __k1 != __k2; ++__k1, (void)++__p)
379  traits_type::assign(*__p, *__k1); // These types are off.
380  }
381 
382  static void
383  _S_copy_chars(_CharT* __p, iterator __k1, iterator __k2) _GLIBCXX_NOEXCEPT
384  { _S_copy_chars(__p, __k1.base(), __k2.base()); }
385 
386  static void
387  _S_copy_chars(_CharT* __p, const_iterator __k1, const_iterator __k2)
388  _GLIBCXX_NOEXCEPT
389  { _S_copy_chars(__p, __k1.base(), __k2.base()); }
390 
391  static void
392  _S_copy_chars(_CharT* __p, _CharT* __k1, _CharT* __k2) _GLIBCXX_NOEXCEPT
393  { _S_copy(__p, __k1, __k2 - __k1); }
394 
395  static void
396  _S_copy_chars(_CharT* __p, const _CharT* __k1, const _CharT* __k2)
397  _GLIBCXX_NOEXCEPT
398  { _S_copy(__p, __k1, __k2 - __k1); }
399 
400  static int
401  _S_compare(size_type __n1, size_type __n2) _GLIBCXX_NOEXCEPT
402  {
403  const difference_type __d = difference_type(__n1 - __n2);
404 
405  if (__d > __gnu_cxx::__numeric_traits<int>::__max)
406  return __gnu_cxx::__numeric_traits<int>::__max;
407  else if (__d < __gnu_cxx::__numeric_traits<int>::__min)
408  return __gnu_cxx::__numeric_traits<int>::__min;
409  else
410  return int(__d);
411  }
412 
413  void
414  _M_assign(const basic_string&);
415 
416  void
417  _M_mutate(size_type __pos, size_type __len1, const _CharT* __s,
418  size_type __len2);
419 
420  void
421  _M_erase(size_type __pos, size_type __n);
422 
423  public:
424  // Construct/copy/destroy:
425  // NB: We overload ctors in some cases instead of using default
426  // arguments, per 17.4.4.4 para. 2 item 2.
427 
428  /**
429  * @brief Default constructor creates an empty string.
430  */
431  basic_string()
432  _GLIBCXX_NOEXCEPT_IF(is_nothrow_default_constructible<_Alloc>::value)
433  : _M_dataplus(_M_local_data())
434  { _M_set_length(0); }
435 
436  /**
437  * @brief Construct an empty string using allocator @a a.
438  */
439  explicit
440  basic_string(const _Alloc& __a) _GLIBCXX_NOEXCEPT
441  : _M_dataplus(_M_local_data(), __a)
442  { _M_set_length(0); }
443 
444  /**
445  * @brief Construct string with copy of value of @a __str.
446  * @param __str Source string.
447  */
448  basic_string(const basic_string& __str)
449  : _M_dataplus(_M_local_data(),
450  _Alloc_traits::_S_select_on_copy(__str._M_get_allocator()))
451  { _M_construct(__str._M_data(), __str._M_data() + __str.length()); }
452 
453  // _GLIBCXX_RESOLVE_LIB_DEFECTS
454  // 2583. no way to supply an allocator for basic_string(str, pos)
455  /**
456  * @brief Construct string as copy of a substring.
457  * @param __str Source string.
458  * @param __pos Index of first character to copy from.
459  * @param __a Allocator to use.
460  */
461  basic_string(const basic_string& __str, size_type __pos,
462  const _Alloc& __a = _Alloc())
463  : _M_dataplus(_M_local_data(), __a)
464  {
465  const _CharT* __start = __str._M_data()
466  + __str._M_check(__pos, "basic_string::basic_string");
467  _M_construct(__start, __start + __str._M_limit(__pos, npos));
468  }
469 
470  /**
471  * @brief Construct string as copy of a substring.
472  * @param __str Source string.
473  * @param __pos Index of first character to copy from.
474  * @param __n Number of characters to copy.
475  */
476  basic_string(const basic_string& __str, size_type __pos,
477  size_type __n)
478  : _M_dataplus(_M_local_data())
479  {
480  const _CharT* __start = __str._M_data()
481  + __str._M_check(__pos, "basic_string::basic_string");
482  _M_construct(__start, __start + __str._M_limit(__pos, __n));
483  }
484 
485  /**
486  * @brief Construct string as copy of a substring.
487  * @param __str Source string.
488  * @param __pos Index of first character to copy from.
489  * @param __n Number of characters to copy.
490  * @param __a Allocator to use.
491  */
492  basic_string(const basic_string& __str, size_type __pos,
493  size_type __n, const _Alloc& __a)
494  : _M_dataplus(_M_local_data(), __a)
495  {
496  const _CharT* __start
497  = __str._M_data() + __str._M_check(__pos, "string::string");
498  _M_construct(__start, __start + __str._M_limit(__pos, __n));
499  }
500 
501  /**
502  * @brief Construct string initialized by a character %array.
503  * @param __s Source character %array.
504  * @param __n Number of characters to copy.
505  * @param __a Allocator to use (default is default allocator).
506  *
507  * NB: @a __s must have at least @a __n characters, &apos;\\0&apos;
508  * has no special meaning.
509  */
510  basic_string(const _CharT* __s, size_type __n,
511  const _Alloc& __a = _Alloc())
512  : _M_dataplus(_M_local_data(), __a)
513  { _M_construct(__s, __s + __n); }
514 
515  /**
516  * @brief Construct string as copy of a C string.
517  * @param __s Source C string.
518  * @param __a Allocator to use (default is default allocator).
519  */
520 #if __cpp_deduction_guides && ! defined _GLIBCXX_DEFINING_STRING_INSTANTIATIONS
521  // _GLIBCXX_RESOLVE_LIB_DEFECTS
522  // 3076. basic_string CTAD ambiguity
523  template<typename = _RequireAllocator<_Alloc>>
524 #endif
525  basic_string(const _CharT* __s, const _Alloc& __a = _Alloc())
526  : _M_dataplus(_M_local_data(), __a)
527  { _M_construct(__s, __s ? __s + traits_type::length(__s) : __s+npos); }
528 
529  /**
530  * @brief Construct string as multiple characters.
531  * @param __n Number of characters.
532  * @param __c Character to use.
533  * @param __a Allocator to use (default is default allocator).
534  */
535 #if __cpp_deduction_guides && ! defined _GLIBCXX_DEFINING_STRING_INSTANTIATIONS
536  // _GLIBCXX_RESOLVE_LIB_DEFECTS
537  // 3076. basic_string CTAD ambiguity
538  template<typename = _RequireAllocator<_Alloc>>
539 #endif
540  basic_string(size_type __n, _CharT __c, const _Alloc& __a = _Alloc())
541  : _M_dataplus(_M_local_data(), __a)
542  { _M_construct(__n, __c); }
543 
544 #if __cplusplus >= 201103L
545  /**
546  * @brief Move construct string.
547  * @param __str Source string.
548  *
549  * The newly-created string contains the exact contents of @a __str.
550  * @a __str is a valid, but unspecified string.
551  */
552  basic_string(basic_string&& __str) noexcept
553  : _M_dataplus(_M_local_data(), std::move(__str._M_get_allocator()))
554  {
555  if (__str._M_is_local())
556  {
557  traits_type::copy(_M_local_buf, __str._M_local_buf,
558  _S_local_capacity + 1);
559  }
560  else
561  {
562  _M_data(__str._M_data());
563  _M_capacity(__str._M_allocated_capacity);
564  }
565 
566  // Must use _M_length() here not _M_set_length() because
567  // basic_stringbuf relies on writing into unallocated capacity so
568  // we mess up the contents if we put a '\0' in the string.
569  _M_length(__str.length());
570  __str._M_data(__str._M_local_data());
571  __str._M_set_length(0);
572  }
573 
574  /**
575  * @brief Construct string from an initializer %list.
576  * @param __l std::initializer_list of characters.
577  * @param __a Allocator to use (default is default allocator).
578  */
579  basic_string(initializer_list<_CharT> __l, const _Alloc& __a = _Alloc())
580  : _M_dataplus(_M_local_data(), __a)
581  { _M_construct(__l.begin(), __l.end()); }
582 
583  basic_string(const basic_string& __str, const _Alloc& __a)
584  : _M_dataplus(_M_local_data(), __a)
585  { _M_construct(__str.begin(), __str.end()); }
586 
587  basic_string(basic_string&& __str, const _Alloc& __a)
588  noexcept(_Alloc_traits::_S_always_equal())
589  : _M_dataplus(_M_local_data(), __a)
590  {
591  if (__str._M_is_local())
592  {
593  traits_type::copy(_M_local_buf, __str._M_local_buf,
594  _S_local_capacity + 1);
595  _M_length(__str.length());
596  __str._M_set_length(0);
597  }
598  else if (_Alloc_traits::_S_always_equal()
599  || __str.get_allocator() == __a)
600  {
601  _M_data(__str._M_data());
602  _M_length(__str.length());
603  _M_capacity(__str._M_allocated_capacity);
604  __str._M_data(__str._M_local_buf);
605  __str._M_set_length(0);
606  }
607  else
608  _M_construct(__str.begin(), __str.end());
609  }
610 
611 #endif // C++11
612 
613  /**
614  * @brief Construct string as copy of a range.
615  * @param __beg Start of range.
616  * @param __end End of range.
617  * @param __a Allocator to use (default is default allocator).
618  */
619 #if __cplusplus >= 201103L
620  template<typename _InputIterator,
621  typename = std::_RequireInputIter<_InputIterator>>
622 #else
623  template<typename _InputIterator>
624 #endif
625  basic_string(_InputIterator __beg, _InputIterator __end,
626  const _Alloc& __a = _Alloc())
627  : _M_dataplus(_M_local_data(), __a)
628  { _M_construct(__beg, __end); }
629 
630 #if __cplusplus >= 201703L
631  /**
632  * @brief Construct string from a substring of a string_view.
633  * @param __t Source object convertible to string view.
634  * @param __pos The index of the first character to copy from __t.
635  * @param __n The number of characters to copy from __t.
636  * @param __a Allocator to use.
637  */
638  template<typename _Tp, typename = _If_sv<_Tp, void>>
639  basic_string(const _Tp& __t, size_type __pos, size_type __n,
640  const _Alloc& __a = _Alloc())
641  : basic_string(_S_to_string_view(__t).substr(__pos, __n), __a) { }
642 
643  /**
644  * @brief Construct string from a string_view.
645  * @param __t Source object convertible to string view.
646  * @param __a Allocator to use (default is default allocator).
647  */
648  template<typename _Tp, typename = _If_sv<_Tp, void>>
649  explicit
650  basic_string(const _Tp& __t, const _Alloc& __a = _Alloc())
651  : basic_string(__sv_wrapper(_S_to_string_view(__t)), __a) { }
652 #endif // C++17
653 
654  /**
655  * @brief Destroy the string instance.
656  */
657  ~basic_string()
658  { _M_dispose(); }
659 
660  /**
661  * @brief Assign the value of @a str to this string.
662  * @param __str Source string.
663  */
664  basic_string&
665  operator=(const basic_string& __str)
666  {
667  return this->assign(__str);
668  }
669 
670  /**
671  * @brief Copy contents of @a s into this string.
672  * @param __s Source null-terminated string.
673  */
674  basic_string&
675  operator=(const _CharT* __s)
676  { return this->assign(__s); }
677 
678  /**
679  * @brief Set value to string of length 1.
680  * @param __c Source character.
681  *
682  * Assigning to a character makes this string length 1 and
683  * (*this)[0] == @a c.
684  */
685  basic_string&
686  operator=(_CharT __c)
687  {
688  this->assign(1, __c);
689  return *this;
690  }
691 
692 #if __cplusplus >= 201103L
693  /**
694  * @brief Move assign the value of @a str to this string.
695  * @param __str Source string.
696  *
697  * The contents of @a str are moved into this string (without copying).
698  * @a str is a valid, but unspecified string.
699  */
700  // _GLIBCXX_RESOLVE_LIB_DEFECTS
701  // 2063. Contradictory requirements for string move assignment
702  basic_string&
703  operator=(basic_string&& __str)
704  noexcept(_Alloc_traits::_S_nothrow_move())
705  {
706  if (!_M_is_local() && _Alloc_traits::_S_propagate_on_move_assign()
707  && !_Alloc_traits::_S_always_equal()
708  && _M_get_allocator() != __str._M_get_allocator())
709  {
710  // Destroy existing storage before replacing allocator.
711  _M_destroy(_M_allocated_capacity);
712  _M_data(_M_local_data());
713  _M_set_length(0);
714  }
715  // Replace allocator if POCMA is true.
716  std::__alloc_on_move(_M_get_allocator(), __str._M_get_allocator());
717 
718  if (__str._M_is_local())
719  {
720  // We've always got room for a short string, just copy it
721  // (unless this is a self-move, because that would violate the
722  // char_traits::copy precondition that the ranges don't overlap).
723  if (__builtin_expect(std::__addressof(__str) != this, true))
724  {
725  if (__str.size())
726  this->_S_copy(_M_data(), __str._M_data(), __str.size());
727  _M_set_length(__str.size());
728  }
729  }
730  else if (_Alloc_traits::_S_propagate_on_move_assign()
731  || _Alloc_traits::_S_always_equal()
732  || _M_get_allocator() == __str._M_get_allocator())
733  {
734  // Just move the allocated pointer, our allocator can free it.
735  pointer __data = nullptr;
736  size_type __capacity;
737  if (!_M_is_local())
738  {
739  if (_Alloc_traits::_S_always_equal())
740  {
741  // __str can reuse our existing storage.
742  __data = _M_data();
743  __capacity = _M_allocated_capacity;
744  }
745  else // __str can't use it, so free it.
746  _M_destroy(_M_allocated_capacity);
747  }
748 
749  _M_data(__str._M_data());
750  _M_length(__str.length());
751  _M_capacity(__str._M_allocated_capacity);
752  if (__data)
753  {
754  __str._M_data(__data);
755  __str._M_capacity(__capacity);
756  }
757  else
758  __str._M_data(__str._M_local_buf);
759  }
760  else // Need to do a deep copy
761  assign(__str);
762  __str.clear();
763  return *this;
764  }
765 
766  /**
767  * @brief Set value to string constructed from initializer %list.
768  * @param __l std::initializer_list.
769  */
770  basic_string&
771  operator=(initializer_list<_CharT> __l)
772  {
773  this->assign(__l.begin(), __l.size());
774  return *this;
775  }
776 #endif // C++11
777 
778 #if __cplusplus >= 201703L
779  /**
780  * @brief Set value to string constructed from a string_view.
781  * @param __svt An object convertible to string_view.
782  */
783  template<typename _Tp>
784  _If_sv<_Tp, basic_string&>
785  operator=(const _Tp& __svt)
786  { return this->assign(__svt); }
787 
788  /**
789  * @brief Convert to a string_view.
790  * @return A string_view.
791  */
792  operator __sv_type() const noexcept
793  { return __sv_type(data(), size()); }
794 #endif // C++17
795 
796  // Iterators:
797  /**
798  * Returns a read/write iterator that points to the first character in
799  * the %string.
800  */
801  iterator
802  begin() _GLIBCXX_NOEXCEPT
803  { return iterator(_M_data()); }
804 
805  /**
806  * Returns a read-only (constant) iterator that points to the first
807  * character in the %string.
808  */
809  const_iterator
810  begin() const _GLIBCXX_NOEXCEPT
811  { return const_iterator(_M_data()); }
812 
813  /**
814  * Returns a read/write iterator that points one past the last
815  * character in the %string.
816  */
817  iterator
818  end() _GLIBCXX_NOEXCEPT
819  { return iterator(_M_data() + this->size()); }
820 
821  /**
822  * Returns a read-only (constant) iterator that points one past the
823  * last character in the %string.
824  */
825  const_iterator
826  end() const _GLIBCXX_NOEXCEPT
827  { return const_iterator(_M_data() + this->size()); }
828 
829  /**
830  * Returns a read/write reverse iterator that points to the last
831  * character in the %string. Iteration is done in reverse element
832  * order.
833  */
834  reverse_iterator
835  rbegin() _GLIBCXX_NOEXCEPT
836  { return reverse_iterator(this->end()); }
837 
838  /**
839  * Returns a read-only (constant) reverse iterator that points
840  * to the last character in the %string. Iteration is done in
841  * reverse element order.
842  */
843  const_reverse_iterator
844  rbegin() const _GLIBCXX_NOEXCEPT
845  { return const_reverse_iterator(this->end()); }
846 
847  /**
848  * Returns a read/write reverse iterator that points to one before the
849  * first character in the %string. Iteration is done in reverse
850  * element order.
851  */
852  reverse_iterator
853  rend() _GLIBCXX_NOEXCEPT
854  { return reverse_iterator(this->begin()); }
855 
856  /**
857  * Returns a read-only (constant) reverse iterator that points
858  * to one before the first character in the %string. Iteration
859  * is done in reverse element order.
860  */
861  const_reverse_iterator
862  rend() const _GLIBCXX_NOEXCEPT
863  { return const_reverse_iterator(this->begin()); }
864 
865 #if __cplusplus >= 201103L
866  /**
867  * Returns a read-only (constant) iterator that points to the first
868  * character in the %string.
869  */
870  const_iterator
871  cbegin() const noexcept
872  { return const_iterator(this->_M_data()); }
873 
874  /**
875  * Returns a read-only (constant) iterator that points one past the
876  * last character in the %string.
877  */
878  const_iterator
879  cend() const noexcept
880  { return const_iterator(this->_M_data() + this->size()); }
881 
882  /**
883  * Returns a read-only (constant) reverse iterator that points
884  * to the last character in the %string. Iteration is done in
885  * reverse element order.
886  */
887  const_reverse_iterator
888  crbegin() const noexcept
889  { return const_reverse_iterator(this->end()); }
890 
891  /**
892  * Returns a read-only (constant) reverse iterator that points
893  * to one before the first character in the %string. Iteration
894  * is done in reverse element order.
895  */
896  const_reverse_iterator
897  crend() const noexcept
898  { return const_reverse_iterator(this->begin()); }
899 #endif
900 
901  public:
902  // Capacity:
903  /// Returns the number of characters in the string, not including any
904  /// null-termination.
905  size_type
906  size() const _GLIBCXX_NOEXCEPT
907  { return _M_string_length; }
908 
909  /// Returns the number of characters in the string, not including any
910  /// null-termination.
911  size_type
912  length() const _GLIBCXX_NOEXCEPT
913  { return _M_string_length; }
914 
915  /// Returns the size() of the largest possible %string.
916  size_type
917  max_size() const _GLIBCXX_NOEXCEPT
918  { return (_Alloc_traits::max_size(_M_get_allocator()) - 1) / 2; }
919 
920  /**
921  * @brief Resizes the %string to the specified number of characters.
922  * @param __n Number of characters the %string should contain.
923  * @param __c Character to fill any new elements.
924  *
925  * This function will %resize the %string to the specified
926  * number of characters. If the number is smaller than the
927  * %string's current size the %string is truncated, otherwise
928  * the %string is extended and new elements are %set to @a __c.
929  */
930  void
931  resize(size_type __n, _CharT __c);
932 
933  /**
934  * @brief Resizes the %string to the specified number of characters.
935  * @param __n Number of characters the %string should contain.
936  *
937  * This function will resize the %string to the specified length. If
938  * the new size is smaller than the %string's current size the %string
939  * is truncated, otherwise the %string is extended and new characters
940  * are default-constructed. For basic types such as char, this means
941  * setting them to 0.
942  */
943  void
944  resize(size_type __n)
945  { this->resize(__n, _CharT()); }
946 
947 #if __cplusplus >= 201103L
948 #pragma GCC diagnostic push
949 #pragma GCC diagnostic ignored "-Wdeprecated-declarations"
950  /// A non-binding request to reduce capacity() to size().
951  void
952  shrink_to_fit() noexcept
953  { reserve(); }
954 #pragma GCC diagnostic pop
955 #endif
956 
957  /**
958  * Returns the total number of characters that the %string can hold
959  * before needing to allocate more memory.
960  */
961  size_type
962  capacity() const _GLIBCXX_NOEXCEPT
963  {
964  return _M_is_local() ? size_type(_S_local_capacity)
965  : _M_allocated_capacity;
966  }
967 
968  /**
969  * @brief Attempt to preallocate enough memory for specified number of
970  * characters.
971  * @param __res_arg Number of characters required.
972  * @throw std::length_error If @a __res_arg exceeds @c max_size().
973  *
974  * This function attempts to reserve enough memory for the
975  * %string to hold the specified number of characters. If the
976  * number requested is more than max_size(), length_error is
977  * thrown.
978  *
979  * The advantage of this function is that if optimal code is a
980  * necessity and the user can determine the string length that will be
981  * required, the user can reserve the memory in %advance, and thus
982  * prevent a possible reallocation of memory and copying of %string
983  * data.
984  */
985  void
986  reserve(size_type __res_arg);
987 
988  /**
989  * Equivalent to shrink_to_fit().
990  */
991 #if __cplusplus > 201703L
992  [[deprecated("use shrink_to_fit() instead")]]
993 #endif
994  void
995  reserve();
996 
997  /**
998  * Erases the string, making it empty.
999  */
1000  void
1001  clear() _GLIBCXX_NOEXCEPT
1002  { _M_set_length(0); }
1003 
1004  /**
1005  * Returns true if the %string is empty. Equivalent to
1006  * <code>*this == ""</code>.
1007  */
1008  _GLIBCXX_NODISCARD bool
1009  empty() const _GLIBCXX_NOEXCEPT
1010  { return this->size() == 0; }
1011 
1012  // Element access:
1013  /**
1014  * @brief Subscript access to the data contained in the %string.
1015  * @param __pos The index of the character to access.
1016  * @return Read-only (constant) reference to the character.
1017  *
1018  * This operator allows for easy, array-style, data access.
1019  * Note that data access with this operator is unchecked and
1020  * out_of_range lookups are not defined. (For checked lookups
1021  * see at().)
1022  */
1023  const_reference
1024  operator[] (size_type __pos) const _GLIBCXX_NOEXCEPT
1025  {
1026  __glibcxx_assert(__pos <= size());
1027  return _M_data()[__pos];
1028  }
1029 
1030  /**
1031  * @brief Subscript access to the data contained in the %string.
1032  * @param __pos The index of the character to access.
1033  * @return Read/write reference to the character.
1034  *
1035  * This operator allows for easy, array-style, data access.
1036  * Note that data access with this operator is unchecked and
1037  * out_of_range lookups are not defined. (For checked lookups
1038  * see at().)
1039  */
1040  reference
1041  operator[](size_type __pos)
1042  {
1043  // Allow pos == size() both in C++98 mode, as v3 extension,
1044  // and in C++11 mode.
1045  __glibcxx_assert(__pos <= size());
1046  // In pedantic mode be strict in C++98 mode.
1047  _GLIBCXX_DEBUG_PEDASSERT(__cplusplus >= 201103L || __pos < size());
1048  return _M_data()[__pos];
1049  }
1050 
1051  /**
1052  * @brief Provides access to the data contained in the %string.
1053  * @param __n The index of the character to access.
1054  * @return Read-only (const) reference to the character.
1055  * @throw std::out_of_range If @a n is an invalid index.
1056  *
1057  * This function provides for safer data access. The parameter is
1058  * first checked that it is in the range of the string. The function
1059  * throws out_of_range if the check fails.
1060  */
1061  const_reference
1062  at(size_type __n) const
1063  {
1064  if (__n >= this->size())
1065  __throw_out_of_range_fmt(__N("basic_string::at: __n "
1066  "(which is %zu) >= this->size() "
1067  "(which is %zu)"),
1068  __n, this->size());
1069  return _M_data()[__n];
1070  }
1071 
1072  /**
1073  * @brief Provides access to the data contained in the %string.
1074  * @param __n The index of the character to access.
1075  * @return Read/write reference to the character.
1076  * @throw std::out_of_range If @a n is an invalid index.
1077  *
1078  * This function provides for safer data access. The parameter is
1079  * first checked that it is in the range of the string. The function
1080  * throws out_of_range if the check fails.
1081  */
1082  reference
1083  at(size_type __n)
1084  {
1085  if (__n >= size())
1086  __throw_out_of_range_fmt(__N("basic_string::at: __n "
1087  "(which is %zu) >= this->size() "
1088  "(which is %zu)"),
1089  __n, this->size());
1090  return _M_data()[__n];
1091  }
1092 
1093 #if __cplusplus >= 201103L
1094  /**
1095  * Returns a read/write reference to the data at the first
1096  * element of the %string.
1097  */
1098  reference
1099  front() noexcept
1100  {
1101  __glibcxx_assert(!empty());
1102  return operator[](0);
1103  }
1104 
1105  /**
1106  * Returns a read-only (constant) reference to the data at the first
1107  * element of the %string.
1108  */
1109  const_reference
1110  front() const noexcept
1111  {
1112  __glibcxx_assert(!empty());
1113  return operator[](0);
1114  }
1115 
1116  /**
1117  * Returns a read/write reference to the data at the last
1118  * element of the %string.
1119  */
1120  reference
1121  back() noexcept
1122  {
1123  __glibcxx_assert(!empty());
1124  return operator[](this->size() - 1);
1125  }
1126 
1127  /**
1128  * Returns a read-only (constant) reference to the data at the
1129  * last element of the %string.
1130  */
1131  const_reference
1132  back() const noexcept
1133  {
1134  __glibcxx_assert(!empty());
1135  return operator[](this->size() - 1);
1136  }
1137 #endif
1138 
1139  // Modifiers:
1140  /**
1141  * @brief Append a string to this string.
1142  * @param __str The string to append.
1143  * @return Reference to this string.
1144  */
1145  basic_string&
1146  operator+=(const basic_string& __str)
1147  { return this->append(__str); }
1148 
1149  /**
1150  * @brief Append a C string.
1151  * @param __s The C string to append.
1152  * @return Reference to this string.
1153  */
1154  basic_string&
1155  operator+=(const _CharT* __s)
1156  { return this->append(__s); }
1157 
1158  /**
1159  * @brief Append a character.
1160  * @param __c The character to append.
1161  * @return Reference to this string.
1162  */
1163  basic_string&
1164  operator+=(_CharT __c)
1165  {
1166  this->push_back(__c);
1167  return *this;
1168  }
1169 
1170 #if __cplusplus >= 201103L
1171  /**
1172  * @brief Append an initializer_list of characters.
1173  * @param __l The initializer_list of characters to be appended.
1174  * @return Reference to this string.
1175  */
1176  basic_string&
1177  operator+=(initializer_list<_CharT> __l)
1178  { return this->append(__l.begin(), __l.size()); }
1179 #endif // C++11
1180 
1181 #if __cplusplus >= 201703L
1182  /**
1183  * @brief Append a string_view.
1184  * @param __svt An object convertible to string_view to be appended.
1185  * @return Reference to this string.
1186  */
1187  template<typename _Tp>
1188  _If_sv<_Tp, basic_string&>
1189  operator+=(const _Tp& __svt)
1190  { return this->append(__svt); }
1191 #endif // C++17
1192 
1193  /**
1194  * @brief Append a string to this string.
1195  * @param __str The string to append.
1196  * @return Reference to this string.
1197  */
1198  basic_string&
1199  append(const basic_string& __str)
1200  { return _M_append(__str._M_data(), __str.size()); }
1201 
1202  /**
1203  * @brief Append a substring.
1204  * @param __str The string to append.
1205  * @param __pos Index of the first character of str to append.
1206  * @param __n The number of characters to append.
1207  * @return Reference to this string.
1208  * @throw std::out_of_range if @a __pos is not a valid index.
1209  *
1210  * This function appends @a __n characters from @a __str
1211  * starting at @a __pos to this string. If @a __n is is larger
1212  * than the number of available characters in @a __str, the
1213  * remainder of @a __str is appended.
1214  */
1215  basic_string&
1216  append(const basic_string& __str, size_type __pos, size_type __n = npos)
1217  { return _M_append(__str._M_data()
1218  + __str._M_check(__pos, "basic_string::append"),
1219  __str._M_limit(__pos, __n)); }
1220 
1221  /**
1222  * @brief Append a C substring.
1223  * @param __s The C string to append.
1224  * @param __n The number of characters to append.
1225  * @return Reference to this string.
1226  */
1227  basic_string&
1228  append(const _CharT* __s, size_type __n)
1229  {
1230  __glibcxx_requires_string_len(__s, __n);
1231  _M_check_length(size_type(0), __n, "basic_string::append");
1232  return _M_append(__s, __n);
1233  }
1234 
1235  /**
1236  * @brief Append a C string.
1237  * @param __s The C string to append.
1238  * @return Reference to this string.
1239  */
1240  basic_string&
1241  append(const _CharT* __s)
1242  {
1243  __glibcxx_requires_string(__s);
1244  const size_type __n = traits_type::length(__s);
1245  _M_check_length(size_type(0), __n, "basic_string::append");
1246  return _M_append(__s, __n);
1247  }
1248 
1249  /**
1250  * @brief Append multiple characters.
1251  * @param __n The number of characters to append.
1252  * @param __c The character to use.
1253  * @return Reference to this string.
1254  *
1255  * Appends __n copies of __c to this string.
1256  */
1257  basic_string&
1258  append(size_type __n, _CharT __c)
1259  { return _M_replace_aux(this->size(), size_type(0), __n, __c); }
1260 
1261 #if __cplusplus >= 201103L
1262  /**
1263  * @brief Append an initializer_list of characters.
1264  * @param __l The initializer_list of characters to append.
1265  * @return Reference to this string.
1266  */
1267  basic_string&
1268  append(initializer_list<_CharT> __l)
1269  { return this->append(__l.begin(), __l.size()); }
1270 #endif // C++11
1271 
1272  /**
1273  * @brief Append a range of characters.
1274  * @param __first Iterator referencing the first character to append.
1275  * @param __last Iterator marking the end of the range.
1276  * @return Reference to this string.
1277  *
1278  * Appends characters in the range [__first,__last) to this string.
1279  */
1280 #if __cplusplus >= 201103L
1281  template<class _InputIterator,
1282  typename = std::_RequireInputIter<_InputIterator>>
1283 #else
1284  template<class _InputIterator>
1285 #endif
1286  basic_string&
1287  append(_InputIterator __first, _InputIterator __last)
1288  { return this->replace(end(), end(), __first, __last); }
1289 
1290 #if __cplusplus >= 201703L
1291  /**
1292  * @brief Append a string_view.
1293  * @param __svt An object convertible to string_view to be appended.
1294  * @return Reference to this string.
1295  */
1296  template<typename _Tp>
1297  _If_sv<_Tp, basic_string&>
1298  append(const _Tp& __svt)
1299  {
1300  __sv_type __sv = __svt;
1301  return this->append(__sv.data(), __sv.size());
1302  }
1303 
1304  /**
1305  * @brief Append a range of characters from a string_view.
1306  * @param __svt An object convertible to string_view to be appended from.
1307  * @param __pos The position in the string_view to append from.
1308  * @param __n The number of characters to append from the string_view.
1309  * @return Reference to this string.
1310  */
1311  template<typename _Tp>
1312  _If_sv<_Tp, basic_string&>
1313  append(const _Tp& __svt, size_type __pos, size_type __n = npos)
1314  {
1315  __sv_type __sv = __svt;
1316  return _M_append(__sv.data()
1317  + std::__sv_check(__sv.size(), __pos, "basic_string::append"),
1318  std::__sv_limit(__sv.size(), __pos, __n));
1319  }
1320 #endif // C++17
1321 
1322  /**
1323  * @brief Append a single character.
1324  * @param __c Character to append.
1325  */
1326  void
1327  push_back(_CharT __c)
1328  {
1329  const size_type __size = this->size();
1330  if (__size + 1 > this->capacity())
1331  this->_M_mutate(__size, size_type(0), 0, size_type(1));
1332  traits_type::assign(this->_M_data()[__size], __c);
1333  this->_M_set_length(__size + 1);
1334  }
1335 
1336  /**
1337  * @brief Set value to contents of another string.
1338  * @param __str Source string to use.
1339  * @return Reference to this string.
1340  */
1341  basic_string&
1342  assign(const basic_string& __str)
1343  {
1344 #if __cplusplus >= 201103L
1345  if (_Alloc_traits::_S_propagate_on_copy_assign())
1346  {
1347  if (!_Alloc_traits::_S_always_equal() && !_M_is_local()
1348  && _M_get_allocator() != __str._M_get_allocator())
1349  {
1350  // Propagating allocator cannot free existing storage so must
1351  // deallocate it before replacing current allocator.
1352  if (__str.size() <= _S_local_capacity)
1353  {
1354  _M_destroy(_M_allocated_capacity);
1355  _M_data(_M_local_data());
1356  _M_set_length(0);
1357  }
1358  else
1359  {
1360  const auto __len = __str.size();
1361  auto __alloc = __str._M_get_allocator();
1362  // If this allocation throws there are no effects:
1363  auto __ptr = _Alloc_traits::allocate(__alloc, __len + 1);
1364  _M_destroy(_M_allocated_capacity);
1365  _M_data(__ptr);
1366  _M_capacity(__len);
1367  _M_set_length(__len);
1368  }
1369  }
1370  std::__alloc_on_copy(_M_get_allocator(), __str._M_get_allocator());
1371  }
1372 #endif
1373  this->_M_assign(__str);
1374  return *this;
1375  }
1376 
1377 #if __cplusplus >= 201103L
1378  /**
1379  * @brief Set value to contents of another string.
1380  * @param __str Source string to use.
1381  * @return Reference to this string.
1382  *
1383  * This function sets this string to the exact contents of @a __str.
1384  * @a __str is a valid, but unspecified string.
1385  */
1386  basic_string&
1387  assign(basic_string&& __str)
1388  noexcept(_Alloc_traits::_S_nothrow_move())
1389  {
1390  // _GLIBCXX_RESOLVE_LIB_DEFECTS
1391  // 2063. Contradictory requirements for string move assignment
1392  return *this = std::move(__str);
1393  }
1394 #endif // C++11
1395 
1396  /**
1397  * @brief Set value to a substring of a string.
1398  * @param __str The string to use.
1399  * @param __pos Index of the first character of str.
1400  * @param __n Number of characters to use.
1401  * @return Reference to this string.
1402  * @throw std::out_of_range if @a pos is not a valid index.
1403  *
1404  * This function sets this string to the substring of @a __str
1405  * consisting of @a __n characters at @a __pos. If @a __n is
1406  * is larger than the number of available characters in @a
1407  * __str, the remainder of @a __str is used.
1408  */
1409  basic_string&
1410  assign(const basic_string& __str, size_type __pos, size_type __n = npos)
1411  { return _M_replace(size_type(0), this->size(), __str._M_data()
1412  + __str._M_check(__pos, "basic_string::assign"),
1413  __str._M_limit(__pos, __n)); }
1414 
1415  /**
1416  * @brief Set value to a C substring.
1417  * @param __s The C string to use.
1418  * @param __n Number of characters to use.
1419  * @return Reference to this string.
1420  *
1421  * This function sets the value of this string to the first @a __n
1422  * characters of @a __s. If @a __n is is larger than the number of
1423  * available characters in @a __s, the remainder of @a __s is used.
1424  */
1425  basic_string&
1426  assign(const _CharT* __s, size_type __n)
1427  {
1428  __glibcxx_requires_string_len(__s, __n);
1429  return _M_replace(size_type(0), this->size(), __s, __n);
1430  }
1431 
1432  /**
1433  * @brief Set value to contents of a C string.
1434  * @param __s The C string to use.
1435  * @return Reference to this string.
1436  *
1437  * This function sets the value of this string to the value of @a __s.
1438  * The data is copied, so there is no dependence on @a __s once the
1439  * function returns.
1440  */
1441  basic_string&
1442  assign(const _CharT* __s)
1443  {
1444  __glibcxx_requires_string(__s);
1445  return _M_replace(size_type(0), this->size(), __s,
1446  traits_type::length(__s));
1447  }
1448 
1449  /**
1450  * @brief Set value to multiple characters.
1451  * @param __n Length of the resulting string.
1452  * @param __c The character to use.
1453  * @return Reference to this string.
1454  *
1455  * This function sets the value of this string to @a __n copies of
1456  * character @a __c.
1457  */
1458  basic_string&
1459  assign(size_type __n, _CharT __c)
1460  { return _M_replace_aux(size_type(0), this->size(), __n, __c); }
1461 
1462  /**
1463  * @brief Set value to a range of characters.
1464  * @param __first Iterator referencing the first character to append.
1465  * @param __last Iterator marking the end of the range.
1466  * @return Reference to this string.
1467  *
1468  * Sets value of string to characters in the range [__first,__last).
1469  */
1470 #if __cplusplus >= 201103L
1471  template<class _InputIterator,
1472  typename = std::_RequireInputIter<_InputIterator>>
1473 #else
1474  template<class _InputIterator>
1475 #endif
1476  basic_string&
1477  assign(_InputIterator __first, _InputIterator __last)
1478  { return this->replace(begin(), end(), __first, __last); }
1479 
1480 #if __cplusplus >= 201103L
1481  /**
1482  * @brief Set value to an initializer_list of characters.
1483  * @param __l The initializer_list of characters to assign.
1484  * @return Reference to this string.
1485  */
1486  basic_string&
1487  assign(initializer_list<_CharT> __l)
1488  { return this->assign(__l.begin(), __l.size()); }
1489 #endif // C++11
1490 
1491 #if __cplusplus >= 201703L
1492  /**
1493  * @brief Set value from a string_view.
1494  * @param __svt The source object convertible to string_view.
1495  * @return Reference to this string.
1496  */
1497  template<typename _Tp>
1498  _If_sv<_Tp, basic_string&>
1499  assign(const _Tp& __svt)
1500  {
1501  __sv_type __sv = __svt;
1502  return this->assign(__sv.data(), __sv.size());
1503  }
1504 
1505  /**
1506  * @brief Set value from a range of characters in a string_view.
1507  * @param __svt The source object convertible to string_view.
1508  * @param __pos The position in the string_view to assign from.
1509  * @param __n The number of characters to assign.
1510  * @return Reference to this string.
1511  */
1512  template<typename _Tp>
1513  _If_sv<_Tp, basic_string&>
1514  assign(const _Tp& __svt, size_type __pos, size_type __n = npos)
1515  {
1516  __sv_type __sv = __svt;
1517  return _M_replace(size_type(0), this->size(),
1518  __sv.data()
1519  + std::__sv_check(__sv.size(), __pos, "basic_string::assign"),
1520  std::__sv_limit(__sv.size(), __pos, __n));
1521  }
1522 #endif // C++17
1523 
1524 #if __cplusplus >= 201103L
1525  /**
1526  * @brief Insert multiple characters.
1527  * @param __p Const_iterator referencing location in string to
1528  * insert at.
1529  * @param __n Number of characters to insert
1530  * @param __c The character to insert.
1531  * @return Iterator referencing the first inserted char.
1532  * @throw std::length_error If new length exceeds @c max_size().
1533  *
1534  * Inserts @a __n copies of character @a __c starting at the
1535  * position referenced by iterator @a __p. If adding
1536  * characters causes the length to exceed max_size(),
1537  * length_error is thrown. The value of the string doesn't
1538  * change if an error is thrown.
1539  */
1540  iterator
1541  insert(const_iterator __p, size_type __n, _CharT __c)
1542  {
1543  _GLIBCXX_DEBUG_PEDASSERT(__p >= begin() && __p <= end());
1544  const size_type __pos = __p - begin();
1545  this->replace(__p, __p, __n, __c);
1546  return iterator(this->_M_data() + __pos);
1547  }
1548 #else
1549  /**
1550  * @brief Insert multiple characters.
1551  * @param __p Iterator referencing location in string to insert at.
1552  * @param __n Number of characters to insert
1553  * @param __c The character to insert.
1554  * @throw std::length_error If new length exceeds @c max_size().
1555  *
1556  * Inserts @a __n copies of character @a __c starting at the
1557  * position referenced by iterator @a __p. If adding
1558  * characters causes the length to exceed max_size(),
1559  * length_error is thrown. The value of the string doesn't
1560  * change if an error is thrown.
1561  */
1562  void
1563  insert(iterator __p, size_type __n, _CharT __c)
1564  { this->replace(__p, __p, __n, __c); }
1565 #endif
1566 
1567 #if __cplusplus >= 201103L
1568  /**
1569  * @brief Insert a range of characters.
1570  * @param __p Const_iterator referencing location in string to
1571  * insert at.
1572  * @param __beg Start of range.
1573  * @param __end End of range.
1574  * @return Iterator referencing the first inserted char.
1575  * @throw std::length_error If new length exceeds @c max_size().
1576  *
1577  * Inserts characters in range [beg,end). If adding characters
1578  * causes the length to exceed max_size(), length_error is
1579  * thrown. The value of the string doesn't change if an error
1580  * is thrown.
1581  */
1582  template<class _InputIterator,
1583  typename = std::_RequireInputIter<_InputIterator>>
1584  iterator
1585  insert(const_iterator __p, _InputIterator __beg, _InputIterator __end)
1586  {
1587  _GLIBCXX_DEBUG_PEDASSERT(__p >= begin() && __p <= end());
1588  const size_type __pos = __p - begin();
1589  this->replace(__p, __p, __beg, __end);
1590  return iterator(this->_M_data() + __pos);
1591  }
1592 #else
1593  /**
1594  * @brief Insert a range of characters.
1595  * @param __p Iterator referencing location in string to insert at.
1596  * @param __beg Start of range.
1597  * @param __end End of range.
1598  * @throw std::length_error If new length exceeds @c max_size().
1599  *
1600  * Inserts characters in range [__beg,__end). If adding
1601  * characters causes the length to exceed max_size(),
1602  * length_error is thrown. The value of the string doesn't
1603  * change if an error is thrown.
1604  */
1605  template<class _InputIterator>
1606  void
1607  insert(iterator __p, _InputIterator __beg, _InputIterator __end)
1608  { this->replace(__p, __p, __beg, __end); }
1609 #endif
1610 
1611 #if __cplusplus >= 201103L
1612  /**
1613  * @brief Insert an initializer_list of characters.
1614  * @param __p Iterator referencing location in string to insert at.
1615  * @param __l The initializer_list of characters to insert.
1616  * @throw std::length_error If new length exceeds @c max_size().
1617  */
1618  iterator
1619  insert(const_iterator __p, initializer_list<_CharT> __l)
1620  { return this->insert(__p, __l.begin(), __l.end()); }
1621 
1622 #ifdef _GLIBCXX_DEFINING_STRING_INSTANTIATIONS
1623  // See PR libstdc++/83328
1624  void
1625  insert(iterator __p, initializer_list<_CharT> __l)
1626  {
1627  _GLIBCXX_DEBUG_PEDASSERT(__p >= begin() && __p <= end());
1628  this->insert(__p - begin(), __l.begin(), __l.size());
1629  }
1630 #endif
1631 #endif // C++11
1632 
1633  /**
1634  * @brief Insert value of a string.
1635  * @param __pos1 Position in string to insert at.
1636  * @param __str The string to insert.
1637  * @return Reference to this string.
1638  * @throw std::length_error If new length exceeds @c max_size().
1639  *
1640  * Inserts value of @a __str starting at @a __pos1. If adding
1641  * characters causes the length to exceed max_size(),
1642  * length_error is thrown. The value of the string doesn't
1643  * change if an error is thrown.
1644  */
1645  basic_string&
1646  insert(size_type __pos1, const basic_string& __str)
1647  { return this->replace(__pos1, size_type(0),
1648  __str._M_data(), __str.size()); }
1649 
1650  /**
1651  * @brief Insert a substring.
1652  * @param __pos1 Position in string to insert at.
1653  * @param __str The string to insert.
1654  * @param __pos2 Start of characters in str to insert.
1655  * @param __n Number of characters to insert.
1656  * @return Reference to this string.
1657  * @throw std::length_error If new length exceeds @c max_size().
1658  * @throw std::out_of_range If @a pos1 > size() or
1659  * @a __pos2 > @a str.size().
1660  *
1661  * Starting at @a pos1, insert @a __n character of @a __str
1662  * beginning with @a __pos2. If adding characters causes the
1663  * length to exceed max_size(), length_error is thrown. If @a
1664  * __pos1 is beyond the end of this string or @a __pos2 is
1665  * beyond the end of @a __str, out_of_range is thrown. The
1666  * value of the string doesn't change if an error is thrown.
1667  */
1668  basic_string&
1669  insert(size_type __pos1, const basic_string& __str,
1670  size_type __pos2, size_type __n = npos)
1671  { return this->replace(__pos1, size_type(0), __str._M_data()
1672  + __str._M_check(__pos2, "basic_string::insert"),
1673  __str._M_limit(__pos2, __n)); }
1674 
1675  /**
1676  * @brief Insert a C substring.
1677  * @param __pos Position in string to insert at.
1678  * @param __s The C string to insert.
1679  * @param __n The number of characters to insert.
1680  * @return Reference to this string.
1681  * @throw std::length_error If new length exceeds @c max_size().
1682  * @throw std::out_of_range If @a __pos is beyond the end of this
1683  * string.
1684  *
1685  * Inserts the first @a __n characters of @a __s starting at @a
1686  * __pos. If adding characters causes the length to exceed
1687  * max_size(), length_error is thrown. If @a __pos is beyond
1688  * end(), out_of_range is thrown. The value of the string
1689  * doesn't change if an error is thrown.
1690  */
1691  basic_string&
1692  insert(size_type __pos, const _CharT* __s, size_type __n)
1693  { return this->replace(__pos, size_type(0), __s, __n); }
1694 
1695  /**
1696  * @brief Insert a C string.
1697  * @param __pos Position in string to insert at.
1698  * @param __s The C string to insert.
1699  * @return Reference to this string.
1700  * @throw std::length_error If new length exceeds @c max_size().
1701  * @throw std::out_of_range If @a pos is beyond the end of this
1702  * string.
1703  *
1704  * Inserts the first @a n characters of @a __s starting at @a __pos. If
1705  * adding characters causes the length to exceed max_size(),
1706  * length_error is thrown. If @a __pos is beyond end(), out_of_range is
1707  * thrown. The value of the string doesn't change if an error is
1708  * thrown.
1709  */
1710  basic_string&
1711  insert(size_type __pos, const _CharT* __s)
1712  {
1713  __glibcxx_requires_string(__s);
1714  return this->replace(__pos, size_type(0), __s,
1715  traits_type::length(__s));
1716  }
1717 
1718  /**
1719  * @brief Insert multiple characters.
1720  * @param __pos Index in string to insert at.
1721  * @param __n Number of characters to insert
1722  * @param __c The character to insert.
1723  * @return Reference to this string.
1724  * @throw std::length_error If new length exceeds @c max_size().
1725  * @throw std::out_of_range If @a __pos is beyond the end of this
1726  * string.
1727  *
1728  * Inserts @a __n copies of character @a __c starting at index
1729  * @a __pos. If adding characters causes the length to exceed
1730  * max_size(), length_error is thrown. If @a __pos > length(),
1731  * out_of_range is thrown. The value of the string doesn't
1732  * change if an error is thrown.
1733  */
1734  basic_string&
1735  insert(size_type __pos, size_type __n, _CharT __c)
1736  { return _M_replace_aux(_M_check(__pos, "basic_string::insert"),
1737  size_type(0), __n, __c); }
1738 
1739  /**
1740  * @brief Insert one character.
1741  * @param __p Iterator referencing position in string to insert at.
1742  * @param __c The character to insert.
1743  * @return Iterator referencing newly inserted char.
1744  * @throw std::length_error If new length exceeds @c max_size().
1745  *
1746  * Inserts character @a __c at position referenced by @a __p.
1747  * If adding character causes the length to exceed max_size(),
1748  * length_error is thrown. If @a __p is beyond end of string,
1749  * out_of_range is thrown. The value of the string doesn't
1750  * change if an error is thrown.
1751  */
1752  iterator
1753  insert(__const_iterator __p, _CharT __c)
1754  {
1755  _GLIBCXX_DEBUG_PEDASSERT(__p >= begin() && __p <= end());
1756  const size_type __pos = __p - begin();
1757  _M_replace_aux(__pos, size_type(0), size_type(1), __c);
1758  return iterator(_M_data() + __pos);
1759  }
1760 
1761 #if __cplusplus >= 201703L
1762  /**
1763  * @brief Insert a string_view.
1764  * @param __pos Position in string to insert at.
1765  * @param __svt The object convertible to string_view to insert.
1766  * @return Reference to this string.
1767  */
1768  template<typename _Tp>
1769  _If_sv<_Tp, basic_string&>
1770  insert(size_type __pos, const _Tp& __svt)
1771  {
1772  __sv_type __sv = __svt;
1773  return this->insert(__pos, __sv.data(), __sv.size());
1774  }
1775 
1776  /**
1777  * @brief Insert a string_view.
1778  * @param __pos1 Position in string to insert at.
1779  * @param __svt The object convertible to string_view to insert from.
1780  * @param __pos2 Start of characters in str to insert.
1781  * @param __n The number of characters to insert.
1782  * @return Reference to this string.
1783  */
1784  template<typename _Tp>
1785  _If_sv<_Tp, basic_string&>
1786  insert(size_type __pos1, const _Tp& __svt,
1787  size_type __pos2, size_type __n = npos)
1788  {
1789  __sv_type __sv = __svt;
1790  return this->replace(__pos1, size_type(0),
1791  __sv.data()
1792  + std::__sv_check(__sv.size(), __pos2, "basic_string::insert"),
1793  std::__sv_limit(__sv.size(), __pos2, __n));
1794  }
1795 #endif // C++17
1796 
1797  /**
1798  * @brief Remove characters.
1799  * @param __pos Index of first character to remove (default 0).
1800  * @param __n Number of characters to remove (default remainder).
1801  * @return Reference to this string.
1802  * @throw std::out_of_range If @a pos is beyond the end of this
1803  * string.
1804  *
1805  * Removes @a __n characters from this string starting at @a
1806  * __pos. The length of the string is reduced by @a __n. If
1807  * there are < @a __n characters to remove, the remainder of
1808  * the string is truncated. If @a __p is beyond end of string,
1809  * out_of_range is thrown. The value of the string doesn't
1810  * change if an error is thrown.
1811  */
1812  basic_string&
1813  erase(size_type __pos = 0, size_type __n = npos)
1814  {
1815  _M_check(__pos, "basic_string::erase");
1816  if (__n == npos)
1817  this->_M_set_length(__pos);
1818  else if (__n != 0)
1819  this->_M_erase(__pos, _M_limit(__pos, __n));
1820  return *this;
1821  }
1822 
1823  /**
1824  * @brief Remove one character.
1825  * @param __position Iterator referencing the character to remove.
1826  * @return iterator referencing same location after removal.
1827  *
1828  * Removes the character at @a __position from this string. The value
1829  * of the string doesn't change if an error is thrown.
1830  */
1831  iterator
1832  erase(__const_iterator __position)
1833  {
1834  _GLIBCXX_DEBUG_PEDASSERT(__position >= begin()
1835  && __position < end());
1836  const size_type __pos = __position - begin();
1837  this->_M_erase(__pos, size_type(1));
1838  return iterator(_M_data() + __pos);
1839  }
1840 
1841  /**
1842  * @brief Remove a range of characters.
1843  * @param __first Iterator referencing the first character to remove.
1844  * @param __last Iterator referencing the end of the range.
1845  * @return Iterator referencing location of first after removal.
1846  *
1847  * Removes the characters in the range [first,last) from this string.
1848  * The value of the string doesn't change if an error is thrown.
1849  */
1850  iterator
1851  erase(__const_iterator __first, __const_iterator __last)
1852  {
1853  _GLIBCXX_DEBUG_PEDASSERT(__first >= begin() && __first <= __last
1854  && __last <= end());
1855  const size_type __pos = __first - begin();
1856  if (__last == end())
1857  this->_M_set_length(__pos);
1858  else
1859  this->_M_erase(__pos, __last - __first);
1860  return iterator(this->_M_data() + __pos);
1861  }
1862 
1863 #if __cplusplus >= 201103L
1864  /**
1865  * @brief Remove the last character.
1866  *
1867  * The string must be non-empty.
1868  */
1869  void
1870  pop_back() noexcept
1871  {
1872  __glibcxx_assert(!empty());
1873  _M_erase(size() - 1, 1);
1874  }
1875 #endif // C++11
1876 
1877  /**
1878  * @brief Replace characters with value from another string.
1879  * @param __pos Index of first character to replace.
1880  * @param __n Number of characters to be replaced.
1881  * @param __str String to insert.
1882  * @return Reference to this string.
1883  * @throw std::out_of_range If @a pos is beyond the end of this
1884  * string.
1885  * @throw std::length_error If new length exceeds @c max_size().
1886  *
1887  * Removes the characters in the range [__pos,__pos+__n) from
1888  * this string. In place, the value of @a __str is inserted.
1889  * If @a __pos is beyond end of string, out_of_range is thrown.
1890  * If the length of the result exceeds max_size(), length_error
1891  * is thrown. The value of the string doesn't change if an
1892  * error is thrown.
1893  */
1894  basic_string&
1895  replace(size_type __pos, size_type __n, const basic_string& __str)
1896  { return this->replace(__pos, __n, __str._M_data(), __str.size()); }
1897 
1898  /**
1899  * @brief Replace characters with value from another string.
1900  * @param __pos1 Index of first character to replace.
1901  * @param __n1 Number of characters to be replaced.
1902  * @param __str String to insert.
1903  * @param __pos2 Index of first character of str to use.
1904  * @param __n2 Number of characters from str to use.
1905  * @return Reference to this string.
1906  * @throw std::out_of_range If @a __pos1 > size() or @a __pos2 >
1907  * __str.size().
1908  * @throw std::length_error If new length exceeds @c max_size().
1909  *
1910  * Removes the characters in the range [__pos1,__pos1 + n) from this
1911  * string. In place, the value of @a __str is inserted. If @a __pos is
1912  * beyond end of string, out_of_range is thrown. If the length of the
1913  * result exceeds max_size(), length_error is thrown. The value of the
1914  * string doesn't change if an error is thrown.
1915  */
1916  basic_string&
1917  replace(size_type __pos1, size_type __n1, const basic_string& __str,
1918  size_type __pos2, size_type __n2 = npos)
1919  { return this->replace(__pos1, __n1, __str._M_data()
1920  + __str._M_check(__pos2, "basic_string::replace"),
1921  __str._M_limit(__pos2, __n2)); }
1922 
1923  /**
1924  * @brief Replace characters with value of a C substring.
1925  * @param __pos Index of first character to replace.
1926  * @param __n1 Number of characters to be replaced.
1927  * @param __s C string to insert.
1928  * @param __n2 Number of characters from @a s to use.
1929  * @return Reference to this string.
1930  * @throw std::out_of_range If @a pos1 > size().
1931  * @throw std::length_error If new length exceeds @c max_size().
1932  *
1933  * Removes the characters in the range [__pos,__pos + __n1)
1934  * from this string. In place, the first @a __n2 characters of
1935  * @a __s are inserted, or all of @a __s if @a __n2 is too large. If
1936  * @a __pos is beyond end of string, out_of_range is thrown. If
1937  * the length of result exceeds max_size(), length_error is
1938  * thrown. The value of the string doesn't change if an error
1939  * is thrown.
1940  */
1941  basic_string&
1942  replace(size_type __pos, size_type __n1, const _CharT* __s,
1943  size_type __n2)
1944  {
1945  __glibcxx_requires_string_len(__s, __n2);
1946  return _M_replace(_M_check(__pos, "basic_string::replace"),
1947  _M_limit(__pos, __n1), __s, __n2);
1948  }
1949 
1950  /**
1951  * @brief Replace characters with value of a C string.
1952  * @param __pos Index of first character to replace.
1953  * @param __n1 Number of characters to be replaced.
1954  * @param __s C string to insert.
1955  * @return Reference to this string.
1956  * @throw std::out_of_range If @a pos > size().
1957  * @throw std::length_error If new length exceeds @c max_size().
1958  *
1959  * Removes the characters in the range [__pos,__pos + __n1)
1960  * from this string. In place, the characters of @a __s are
1961  * inserted. If @a __pos is beyond end of string, out_of_range
1962  * is thrown. If the length of result exceeds max_size(),
1963  * length_error is thrown. The value of the string doesn't
1964  * change if an error is thrown.
1965  */
1966  basic_string&
1967  replace(size_type __pos, size_type __n1, const _CharT* __s)
1968  {
1969  __glibcxx_requires_string(__s);
1970  return this->replace(__pos, __n1, __s, traits_type::length(__s));
1971  }
1972 
1973  /**
1974  * @brief Replace characters with multiple characters.
1975  * @param __pos Index of first character to replace.
1976  * @param __n1 Number of characters to be replaced.
1977  * @param __n2 Number of characters to insert.
1978  * @param __c Character to insert.
1979  * @return Reference to this string.
1980  * @throw std::out_of_range If @a __pos > size().
1981  * @throw std::length_error If new length exceeds @c max_size().
1982  *
1983  * Removes the characters in the range [pos,pos + n1) from this
1984  * string. In place, @a __n2 copies of @a __c are inserted.
1985  * If @a __pos is beyond end of string, out_of_range is thrown.
1986  * If the length of result exceeds max_size(), length_error is
1987  * thrown. The value of the string doesn't change if an error
1988  * is thrown.
1989  */
1990  basic_string&
1991  replace(size_type __pos, size_type __n1, size_type __n2, _CharT __c)
1992  { return _M_replace_aux(_M_check(__pos, "basic_string::replace"),
1993  _M_limit(__pos, __n1), __n2, __c); }
1994 
1995  /**
1996  * @brief Replace range of characters with string.
1997  * @param __i1 Iterator referencing start of range to replace.
1998  * @param __i2 Iterator referencing end of range to replace.
1999  * @param __str String value to insert.
2000  * @return Reference to this string.
2001  * @throw std::length_error If new length exceeds @c max_size().
2002  *
2003  * Removes the characters in the range [__i1,__i2). In place,
2004  * the value of @a __str is inserted. If the length of result
2005  * exceeds max_size(), length_error is thrown. The value of
2006  * the string doesn't change if an error is thrown.
2007  */
2008  basic_string&
2009  replace(__const_iterator __i1, __const_iterator __i2,
2010  const basic_string& __str)
2011  { return this->replace(__i1, __i2, __str._M_data(), __str.size()); }
2012 
2013  /**
2014  * @brief Replace range of characters with C substring.
2015  * @param __i1 Iterator referencing start of range to replace.
2016  * @param __i2 Iterator referencing end of range to replace.
2017  * @param __s C string value to insert.
2018  * @param __n Number of characters from s to insert.
2019  * @return Reference to this string.
2020  * @throw std::length_error If new length exceeds @c max_size().
2021  *
2022  * Removes the characters in the range [__i1,__i2). In place,
2023  * the first @a __n characters of @a __s are inserted. If the
2024  * length of result exceeds max_size(), length_error is thrown.
2025  * The value of the string doesn't change if an error is
2026  * thrown.
2027  */
2028  basic_string&
2029  replace(__const_iterator __i1, __const_iterator __i2,
2030  const _CharT* __s, size_type __n)
2031  {
2032  _GLIBCXX_DEBUG_PEDASSERT(begin() <= __i1 && __i1 <= __i2
2033  && __i2 <= end());
2034  return this->replace(__i1 - begin(), __i2 - __i1, __s, __n);
2035  }
2036 
2037  /**
2038  * @brief Replace range of characters with C string.
2039  * @param __i1 Iterator referencing start of range to replace.
2040  * @param __i2 Iterator referencing end of range to replace.
2041  * @param __s C string value to insert.
2042  * @return Reference to this string.
2043  * @throw std::length_error If new length exceeds @c max_size().
2044  *
2045  * Removes the characters in the range [__i1,__i2). In place,
2046  * the characters of @a __s are inserted. If the length of
2047  * result exceeds max_size(), length_error is thrown. The
2048  * value of the string doesn't change if an error is thrown.
2049  */
2050  basic_string&
2051  replace(__const_iterator __i1, __const_iterator __i2, const _CharT* __s)
2052  {
2053  __glibcxx_requires_string(__s);
2054  return this->replace(__i1, __i2, __s, traits_type::length(__s));
2055  }
2056 
2057  /**
2058  * @brief Replace range of characters with multiple characters
2059  * @param __i1 Iterator referencing start of range to replace.
2060  * @param __i2 Iterator referencing end of range to replace.
2061  * @param __n Number of characters to insert.
2062  * @param __c Character to insert.
2063  * @return Reference to this string.
2064  * @throw std::length_error If new length exceeds @c max_size().
2065  *
2066  * Removes the characters in the range [__i1,__i2). In place,
2067  * @a __n copies of @a __c are inserted. If the length of
2068  * result exceeds max_size(), length_error is thrown. The
2069  * value of the string doesn't change if an error is thrown.
2070  */
2071  basic_string&
2072  replace(__const_iterator __i1, __const_iterator __i2, size_type __n,
2073  _CharT __c)
2074  {
2075  _GLIBCXX_DEBUG_PEDASSERT(begin() <= __i1 && __i1 <= __i2
2076  && __i2 <= end());
2077  return _M_replace_aux(__i1 - begin(), __i2 - __i1, __n, __c);
2078  }
2079 
2080  /**
2081  * @brief Replace range of characters with range.
2082  * @param __i1 Iterator referencing start of range to replace.
2083  * @param __i2 Iterator referencing end of range to replace.
2084  * @param __k1 Iterator referencing start of range to insert.
2085  * @param __k2 Iterator referencing end of range to insert.
2086  * @return Reference to this string.
2087  * @throw std::length_error If new length exceeds @c max_size().
2088  *
2089  * Removes the characters in the range [__i1,__i2). In place,
2090  * characters in the range [__k1,__k2) are inserted. If the
2091  * length of result exceeds max_size(), length_error is thrown.
2092  * The value of the string doesn't change if an error is
2093  * thrown.
2094  */
2095 #if __cplusplus >= 201103L
2096  template<class _InputIterator,
2097  typename = std::_RequireInputIter<_InputIterator>>
2098  basic_string&
2099  replace(const_iterator __i1, const_iterator __i2,
2100  _InputIterator __k1, _InputIterator __k2)
2101  {
2102  _GLIBCXX_DEBUG_PEDASSERT(begin() <= __i1 && __i1 <= __i2
2103  && __i2 <= end());
2104  __glibcxx_requires_valid_range(__k1, __k2);
2105  return this->_M_replace_dispatch(__i1, __i2, __k1, __k2,
2106  std::__false_type());
2107  }
2108 #else
2109  template<class _InputIterator>
2110 #ifdef _GLIBCXX_DISAMBIGUATE_REPLACE_INST
2111  typename __enable_if_not_native_iterator<_InputIterator>::__type
2112 #else
2113  basic_string&
2114 #endif
2115  replace(iterator __i1, iterator __i2,
2116  _InputIterator __k1, _InputIterator __k2)
2117  {
2118  _GLIBCXX_DEBUG_PEDASSERT(begin() <= __i1 && __i1 <= __i2
2119  && __i2 <= end());
2120  __glibcxx_requires_valid_range(__k1, __k2);
2121  typedef typename std::__is_integer<_InputIterator>::__type _Integral;
2122  return _M_replace_dispatch(__i1, __i2, __k1, __k2, _Integral());
2123  }
2124 #endif
2125 
2126  // Specializations for the common case of pointer and iterator:
2127  // useful to avoid the overhead of temporary buffering in _M_replace.
2128  basic_string&
2129  replace(__const_iterator __i1, __const_iterator __i2,
2130  _CharT* __k1, _CharT* __k2)
2131  {
2132  _GLIBCXX_DEBUG_PEDASSERT(begin() <= __i1 && __i1 <= __i2
2133  && __i2 <= end());
2134  __glibcxx_requires_valid_range(__k1, __k2);
2135  return this->replace(__i1 - begin(), __i2 - __i1,
2136  __k1, __k2 - __k1);
2137  }
2138 
2139  basic_string&
2140  replace(__const_iterator __i1, __const_iterator __i2,
2141  const _CharT* __k1, const _CharT* __k2)
2142  {
2143  _GLIBCXX_DEBUG_PEDASSERT(begin() <= __i1 && __i1 <= __i2
2144  && __i2 <= end());
2145  __glibcxx_requires_valid_range(__k1, __k2);
2146  return this->replace(__i1 - begin(), __i2 - __i1,
2147  __k1, __k2 - __k1);
2148  }
2149 
2150  basic_string&
2151  replace(__const_iterator __i1, __const_iterator __i2,
2152  iterator __k1, iterator __k2)
2153  {
2154  _GLIBCXX_DEBUG_PEDASSERT(begin() <= __i1 && __i1 <= __i2
2155  && __i2 <= end());
2156  __glibcxx_requires_valid_range(__k1, __k2);
2157  return this->replace(__i1 - begin(), __i2 - __i1,
2158  __k1.base(), __k2 - __k1);
2159  }
2160 
2161  basic_string&
2162  replace(__const_iterator __i1, __const_iterator __i2,
2163  const_iterator __k1, const_iterator __k2)
2164  {
2165  _GLIBCXX_DEBUG_PEDASSERT(begin() <= __i1 && __i1 <= __i2
2166  && __i2 <= end());
2167  __glibcxx_requires_valid_range(__k1, __k2);
2168  return this->replace(__i1 - begin(), __i2 - __i1,
2169  __k1.base(), __k2 - __k1);
2170  }
2171 
2172 #if __cplusplus >= 201103L
2173  /**
2174  * @brief Replace range of characters with initializer_list.
2175  * @param __i1 Iterator referencing start of range to replace.
2176  * @param __i2 Iterator referencing end of range to replace.
2177  * @param __l The initializer_list of characters to insert.
2178  * @return Reference to this string.
2179  * @throw std::length_error If new length exceeds @c max_size().
2180  *
2181  * Removes the characters in the range [__i1,__i2). In place,
2182  * characters in the range [__k1,__k2) are inserted. If the
2183  * length of result exceeds max_size(), length_error is thrown.
2184  * The value of the string doesn't change if an error is
2185  * thrown.
2186  */
2187  basic_string& replace(const_iterator __i1, const_iterator __i2,
2188  initializer_list<_CharT> __l)
2189  { return this->replace(__i1, __i2, __l.begin(), __l.size()); }
2190 #endif // C++11
2191 
2192 #if __cplusplus >= 201703L
2193  /**
2194  * @brief Replace range of characters with string_view.
2195  * @param __pos The position to replace at.
2196  * @param __n The number of characters to replace.
2197  * @param __svt The object convertible to string_view to insert.
2198  * @return Reference to this string.
2199  */
2200  template<typename _Tp>
2201  _If_sv<_Tp, basic_string&>
2202  replace(size_type __pos, size_type __n, const _Tp& __svt)
2203  {
2204  __sv_type __sv = __svt;
2205  return this->replace(__pos, __n, __sv.data(), __sv.size());
2206  }
2207 
2208  /**
2209  * @brief Replace range of characters with string_view.
2210  * @param __pos1 The position to replace at.
2211  * @param __n1 The number of characters to replace.
2212  * @param __svt The object convertible to string_view to insert from.
2213  * @param __pos2 The position in the string_view to insert from.
2214  * @param __n2 The number of characters to insert.
2215  * @return Reference to this string.
2216  */
2217  template<typename _Tp>
2218  _If_sv<_Tp, basic_string&>
2219  replace(size_type __pos1, size_type __n1, const _Tp& __svt,
2220  size_type __pos2, size_type __n2 = npos)
2221  {
2222  __sv_type __sv = __svt;
2223  return this->replace(__pos1, __n1,
2224  __sv.data()
2225  + std::__sv_check(__sv.size(), __pos2, "basic_string::replace"),
2226  std::__sv_limit(__sv.size(), __pos2, __n2));
2227  }
2228 
2229  /**
2230  * @brief Replace range of characters with string_view.
2231  * @param __i1 An iterator referencing the start position
2232  to replace at.
2233  * @param __i2 An iterator referencing the end position
2234  for the replace.
2235  * @param __svt The object convertible to string_view to insert from.
2236  * @return Reference to this string.
2237  */
2238  template<typename _Tp>
2239  _If_sv<_Tp, basic_string&>
2240  replace(const_iterator __i1, const_iterator __i2, const _Tp& __svt)
2241  {
2242  __sv_type __sv = __svt;
2243  return this->replace(__i1 - begin(), __i2 - __i1, __sv);
2244  }
2245 #endif // C++17
2246 
2247  private:
2248  template<class _Integer>
2249  basic_string&
2250  _M_replace_dispatch(const_iterator __i1, const_iterator __i2,
2251  _Integer __n, _Integer __val, __true_type)
2252  { return _M_replace_aux(__i1 - begin(), __i2 - __i1, __n, __val); }
2253 
2254  template<class _InputIterator>
2255  basic_string&
2256  _M_replace_dispatch(const_iterator __i1, const_iterator __i2,
2257  _InputIterator __k1, _InputIterator __k2,
2258  __false_type);
2259 
2260  basic_string&
2261  _M_replace_aux(size_type __pos1, size_type __n1, size_type __n2,
2262  _CharT __c);
2263 
2264  basic_string&
2265  _M_replace(size_type __pos, size_type __len1, const _CharT* __s,
2266  const size_type __len2);
2267 
2268  basic_string&
2269  _M_append(const _CharT* __s, size_type __n);
2270 
2271  public:
2272 
2273  /**
2274  * @brief Copy substring into C string.
2275  * @param __s C string to copy value into.
2276  * @param __n Number of characters to copy.
2277  * @param __pos Index of first character to copy.
2278  * @return Number of characters actually copied
2279  * @throw std::out_of_range If __pos > size().
2280  *
2281  * Copies up to @a __n characters starting at @a __pos into the
2282  * C string @a __s. If @a __pos is %greater than size(),
2283  * out_of_range is thrown.
2284  */
2285  size_type
2286  copy(_CharT* __s, size_type __n, size_type __pos = 0) const;
2287 
2288  /**
2289  * @brief Swap contents with another string.
2290  * @param __s String to swap with.
2291  *
2292  * Exchanges the contents of this string with that of @a __s in constant
2293  * time.
2294  */
2295  void
2296  swap(basic_string& __s) _GLIBCXX_NOEXCEPT;
2297 
2298  // String operations:
2299  /**
2300  * @brief Return const pointer to null-terminated contents.
2301  *
2302  * This is a handle to internal data. Do not modify or dire things may
2303  * happen.
2304  */
2305  const _CharT*
2306  c_str() const _GLIBCXX_NOEXCEPT
2307  { return _M_data(); }
2308 
2309  /**
2310  * @brief Return const pointer to contents.
2311  *
2312  * This is a pointer to internal data. It is undefined to modify
2313  * the contents through the returned pointer. To get a pointer that
2314  * allows modifying the contents use @c &str[0] instead,
2315  * (or in C++17 the non-const @c str.data() overload).
2316  */
2317  const _CharT*
2318  data() const _GLIBCXX_NOEXCEPT
2319  { return _M_data(); }
2320 
2321 #if __cplusplus >= 201703L
2322  /**
2323  * @brief Return non-const pointer to contents.
2324  *
2325  * This is a pointer to the character sequence held by the string.
2326  * Modifying the characters in the sequence is allowed.
2327  */
2328  _CharT*
2329  data() noexcept
2330  { return _M_data(); }
2331 #endif
2332 
2333  /**
2334  * @brief Return copy of allocator used to construct this string.
2335  */
2336  allocator_type
2337  get_allocator() const _GLIBCXX_NOEXCEPT
2338  { return _M_get_allocator(); }
2339 
2340  /**
2341  * @brief Find position of a C substring.
2342  * @param __s C string to locate.
2343  * @param __pos Index of character to search from.
2344  * @param __n Number of characters from @a s to search for.
2345  * @return Index of start of first occurrence.
2346  *
2347  * Starting from @a __pos, searches forward for the first @a
2348  * __n characters in @a __s within this string. If found,
2349  * returns the index where it begins. If not found, returns
2350  * npos.
2351  */
2352  size_type
2353  find(const _CharT* __s, size_type __pos, size_type __n) const
2354  _GLIBCXX_NOEXCEPT;
2355 
2356  /**
2357  * @brief Find position of a string.
2358  * @param __str String to locate.
2359  * @param __pos Index of character to search from (default 0).
2360  * @return Index of start of first occurrence.
2361  *
2362  * Starting from @a __pos, searches forward for value of @a __str within
2363  * this string. If found, returns the index where it begins. If not
2364  * found, returns npos.
2365  */
2366  size_type
2367  find(const basic_string& __str, size_type __pos = 0) const
2368  _GLIBCXX_NOEXCEPT
2369  { return this->find(__str.data(), __pos, __str.size()); }
2370 
2371 #if __cplusplus >= 201703L
2372  /**
2373  * @brief Find position of a string_view.
2374  * @param __svt The object convertible to string_view to locate.
2375  * @param __pos Index of character to search from (default 0).
2376  * @return Index of start of first occurrence.
2377  */
2378  template<typename _Tp>
2379  _If_sv<_Tp, size_type>
2380  find(const _Tp& __svt, size_type __pos = 0) const
2381  noexcept(is_same<_Tp, __sv_type>::value)
2382  {
2383  __sv_type __sv = __svt;
2384  return this->find(__sv.data(), __pos, __sv.size());
2385  }
2386 #endif // C++17
2387 
2388  /**
2389  * @brief Find position of a C string.
2390  * @param __s C string to locate.
2391  * @param __pos Index of character to search from (default 0).
2392  * @return Index of start of first occurrence.
2393  *
2394  * Starting from @a __pos, searches forward for the value of @a
2395  * __s within this string. If found, returns the index where
2396  * it begins. If not found, returns npos.
2397  */
2398  size_type
2399  find(const _CharT* __s, size_type __pos = 0) const _GLIBCXX_NOEXCEPT
2400  {
2401  __glibcxx_requires_string(__s);
2402  return this->find(__s, __pos, traits_type::length(__s));
2403  }
2404 
2405  /**
2406  * @brief Find position of a character.
2407  * @param __c Character to locate.
2408  * @param __pos Index of character to search from (default 0).
2409  * @return Index of first occurrence.
2410  *
2411  * Starting from @a __pos, searches forward for @a __c within
2412  * this string. If found, returns the index where it was
2413  * found. If not found, returns npos.
2414  */
2415  size_type
2416  find(_CharT __c, size_type __pos = 0) const _GLIBCXX_NOEXCEPT;
2417 
2418  /**
2419  * @brief Find last position of a string.
2420  * @param __str String to locate.
2421  * @param __pos Index of character to search back from (default end).
2422  * @return Index of start of last occurrence.
2423  *
2424  * Starting from @a __pos, searches backward for value of @a
2425  * __str within this string. If found, returns the index where
2426  * it begins. If not found, returns npos.
2427  */
2428  size_type
2429  rfind(const basic_string& __str, size_type __pos = npos) const
2430  _GLIBCXX_NOEXCEPT
2431  { return this->rfind(__str.data(), __pos, __str.size()); }
2432 
2433 #if __cplusplus >= 201703L
2434  /**
2435  * @brief Find last position of a string_view.
2436  * @param __svt The object convertible to string_view to locate.
2437  * @param __pos Index of character to search back from (default end).
2438  * @return Index of start of last occurrence.
2439  */
2440  template<typename _Tp>
2441  _If_sv<_Tp, size_type>
2442  rfind(const _Tp& __svt, size_type __pos = npos) const
2443  noexcept(is_same<_Tp, __sv_type>::value)
2444  {
2445  __sv_type __sv = __svt;
2446  return this->rfind(__sv.data(), __pos, __sv.size());
2447  }
2448 #endif // C++17
2449 
2450  /**
2451  * @brief Find last position of a C substring.
2452  * @param __s C string to locate.
2453  * @param __pos Index of character to search back from.
2454  * @param __n Number of characters from s to search for.
2455  * @return Index of start of last occurrence.
2456  *
2457  * Starting from @a __pos, searches backward for the first @a
2458  * __n characters in @a __s within this string. If found,
2459  * returns the index where it begins. If not found, returns
2460  * npos.
2461  */
2462  size_type
2463  rfind(const _CharT* __s, size_type __pos, size_type __n) const
2464  _GLIBCXX_NOEXCEPT;
2465 
2466  /**
2467  * @brief Find last position of a C string.
2468  * @param __s C string to locate.
2469  * @param __pos Index of character to start search at (default end).
2470  * @return Index of start of last occurrence.
2471  *
2472  * Starting from @a __pos, searches backward for the value of
2473  * @a __s within this string. If found, returns the index
2474  * where it begins. If not found, returns npos.
2475  */
2476  size_type
2477  rfind(const _CharT* __s, size_type __pos = npos) const
2478  {
2479  __glibcxx_requires_string(__s);
2480  return this->rfind(__s, __pos, traits_type::length(__s));
2481  }
2482 
2483  /**
2484  * @brief Find last position of a character.
2485  * @param __c Character to locate.
2486  * @param __pos Index of character to search back from (default end).
2487  * @return Index of last occurrence.
2488  *
2489  * Starting from @a __pos, searches backward for @a __c within
2490  * this string. If found, returns the index where it was
2491  * found. If not found, returns npos.
2492  */
2493  size_type
2494  rfind(_CharT __c, size_type __pos = npos) const _GLIBCXX_NOEXCEPT;
2495 
2496  /**
2497  * @brief Find position of a character of string.
2498  * @param __str String containing characters to locate.
2499  * @param __pos Index of character to search from (default 0).
2500  * @return Index of first occurrence.
2501  *
2502  * Starting from @a __pos, searches forward for one of the
2503  * characters of @a __str within this string. If found,
2504  * returns the index where it was found. If not found, returns
2505  * npos.
2506  */
2507  size_type
2508  find_first_of(const basic_string& __str, size_type __pos = 0) const
2509  _GLIBCXX_NOEXCEPT
2510  { return this->find_first_of(__str.data(), __pos, __str.size()); }
2511 
2512 #if __cplusplus >= 201703L
2513  /**
2514  * @brief Find position of a character of a string_view.
2515  * @param __svt An object convertible to string_view containing
2516  * characters to locate.
2517  * @param __pos Index of character to search from (default 0).
2518  * @return Index of first occurrence.
2519  */
2520  template<typename _Tp>
2521  _If_sv<_Tp, size_type>
2522  find_first_of(const _Tp& __svt, size_type __pos = 0) const
2523  noexcept(is_same<_Tp, __sv_type>::value)
2524  {
2525  __sv_type __sv = __svt;
2526  return this->find_first_of(__sv.data(), __pos, __sv.size());
2527  }
2528 #endif // C++17
2529 
2530  /**
2531  * @brief Find position of a character of C substring.
2532  * @param __s String containing characters to locate.
2533  * @param __pos Index of character to search from.
2534  * @param __n Number of characters from s to search for.
2535  * @return Index of first occurrence.
2536  *
2537  * Starting from @a __pos, searches forward for one of the
2538  * first @a __n characters of @a __s within this string. If
2539  * found, returns the index where it was found. If not found,
2540  * returns npos.
2541  */
2542  size_type
2543  find_first_of(const _CharT* __s, size_type __pos, size_type __n) const
2544  _GLIBCXX_NOEXCEPT;
2545 
2546  /**
2547  * @brief Find position of a character of C string.
2548  * @param __s String containing characters to locate.
2549  * @param __pos Index of character to search from (default 0).
2550  * @return Index of first occurrence.
2551  *
2552  * Starting from @a __pos, searches forward for one of the
2553  * characters of @a __s within this string. If found, returns
2554  * the index where it was found. If not found, returns npos.
2555  */
2556  size_type
2557  find_first_of(const _CharT* __s, size_type __pos = 0) const
2558  _GLIBCXX_NOEXCEPT
2559  {
2560  __glibcxx_requires_string(__s);
2561  return this->find_first_of(__s, __pos, traits_type::length(__s));
2562  }
2563 
2564  /**
2565  * @brief Find position of a character.
2566  * @param __c Character to locate.
2567  * @param __pos Index of character to search from (default 0).
2568  * @return Index of first occurrence.
2569  *
2570  * Starting from @a __pos, searches forward for the character
2571  * @a __c within this string. If found, returns the index
2572  * where it was found. If not found, returns npos.
2573  *
2574  * Note: equivalent to find(__c, __pos).
2575  */
2576  size_type
2577  find_first_of(_CharT __c, size_type __pos = 0) const _GLIBCXX_NOEXCEPT
2578  { return this->find(__c, __pos); }
2579 
2580  /**
2581  * @brief Find last position of a character of string.
2582  * @param __str String containing characters to locate.
2583  * @param __pos Index of character to search back from (default end).
2584  * @return Index of last occurrence.
2585  *
2586  * Starting from @a __pos, searches backward for one of the
2587  * characters of @a __str within this string. If found,
2588  * returns the index where it was found. If not found, returns
2589  * npos.
2590  */
2591  size_type
2592  find_last_of(const basic_string& __str, size_type __pos = npos) const
2593  _GLIBCXX_NOEXCEPT
2594  { return this->find_last_of(__str.data(), __pos, __str.size()); }
2595 
2596 #if __cplusplus >= 201703L
2597  /**
2598  * @brief Find last position of a character of string.
2599  * @param __svt An object convertible to string_view containing
2600  * characters to locate.
2601  * @param __pos Index of character to search back from (default end).
2602  * @return Index of last occurrence.
2603  */
2604  template<typename _Tp>
2605  _If_sv<_Tp, size_type>
2606  find_last_of(const _Tp& __svt, size_type __pos = npos) const
2607  noexcept(is_same<_Tp, __sv_type>::value)
2608  {
2609  __sv_type __sv = __svt;
2610  return this->find_last_of(__sv.data(), __pos, __sv.size());
2611  }
2612 #endif // C++17
2613 
2614  /**
2615  * @brief Find last position of a character of C substring.
2616  * @param __s C string containing characters to locate.
2617  * @param __pos Index of character to search back from.
2618  * @param __n Number of characters from s to search for.
2619  * @return Index of last occurrence.
2620  *
2621  * Starting from @a __pos, searches backward for one of the
2622  * first @a __n characters of @a __s within this string. If
2623  * found, returns the index where it was found. If not found,
2624  * returns npos.
2625  */
2626  size_type
2627  find_last_of(const _CharT* __s, size_type __pos, size_type __n) const
2628  _GLIBCXX_NOEXCEPT;
2629 
2630  /**
2631  * @brief Find last position of a character of C string.
2632  * @param __s C string containing characters to locate.
2633  * @param __pos Index of character to search back from (default end).
2634  * @return Index of last occurrence.
2635  *
2636  * Starting from @a __pos, searches backward for one of the
2637  * characters of @a __s within this string. If found, returns
2638  * the index where it was found. If not found, returns npos.
2639  */
2640  size_type
2641  find_last_of(const _CharT* __s, size_type __pos = npos) const
2642  _GLIBCXX_NOEXCEPT
2643  {
2644  __glibcxx_requires_string(__s);
2645  return this->find_last_of(__s, __pos, traits_type::length(__s));
2646  }
2647 
2648  /**
2649  * @brief Find last position of a character.
2650  * @param __c Character to locate.
2651  * @param __pos Index of character to search back from (default end).
2652  * @return Index of last occurrence.
2653  *
2654  * Starting from @a __pos, searches backward for @a __c within
2655  * this string. If found, returns the index where it was
2656  * found. If not found, returns npos.
2657  *
2658  * Note: equivalent to rfind(__c, __pos).
2659  */
2660  size_type
2661  find_last_of(_CharT __c, size_type __pos = npos) const _GLIBCXX_NOEXCEPT
2662  { return this->rfind(__c, __pos); }
2663 
2664  /**
2665  * @brief Find position of a character not in string.
2666  * @param __str String containing characters to avoid.
2667  * @param __pos Index of character to search from (default 0).
2668  * @return Index of first occurrence.
2669  *
2670  * Starting from @a __pos, searches forward for a character not contained
2671  * in @a __str within this string. If found, returns the index where it
2672  * was found. If not found, returns npos.
2673  */
2674  size_type
2675  find_first_not_of(const basic_string& __str, size_type __pos = 0) const
2676  _GLIBCXX_NOEXCEPT
2677  { return this->find_first_not_of(__str.data(), __pos, __str.size()); }
2678 
2679 #if __cplusplus >= 201703L
2680  /**
2681  * @brief Find position of a character not in a string_view.
2682  * @param __svt A object convertible to string_view containing
2683  * characters to avoid.
2684  * @param __pos Index of character to search from (default 0).
2685  * @return Index of first occurrence.
2686  */
2687  template<typename _Tp>
2688  _If_sv<_Tp, size_type>
2689  find_first_not_of(const _Tp& __svt, size_type __pos = 0) const
2690  noexcept(is_same<_Tp, __sv_type>::value)
2691  {
2692  __sv_type __sv = __svt;
2693  return this->find_first_not_of(__sv.data(), __pos, __sv.size());
2694  }
2695 #endif // C++17
2696 
2697  /**
2698  * @brief Find position of a character not in C substring.
2699  * @param __s C string containing characters to avoid.
2700  * @param __pos Index of character to search from.
2701  * @param __n Number of characters from __s to consider.
2702  * @return Index of first occurrence.
2703  *
2704  * Starting from @a __pos, searches forward for a character not
2705  * contained in the first @a __n characters of @a __s within
2706  * this string. If found, returns the index where it was
2707  * found. If not found, returns npos.
2708  */
2709  size_type
2710  find_first_not_of(const _CharT* __s, size_type __pos,
2711  size_type __n) const _GLIBCXX_NOEXCEPT;
2712 
2713  /**
2714  * @brief Find position of a character not in C string.
2715  * @param __s C string containing characters to avoid.
2716  * @param __pos Index of character to search from (default 0).
2717  * @return Index of first occurrence.
2718  *
2719  * Starting from @a __pos, searches forward for a character not
2720  * contained in @a __s within this string. If found, returns
2721  * the index where it was found. If not found, returns npos.
2722  */
2723  size_type
2724  find_first_not_of(const _CharT* __s, size_type __pos = 0) const
2725  _GLIBCXX_NOEXCEPT
2726  {
2727  __glibcxx_requires_string(__s);
2728  return this->find_first_not_of(__s, __pos, traits_type::length(__s));
2729  }
2730 
2731  /**
2732  * @brief Find position of a different character.
2733  * @param __c Character to avoid.
2734  * @param __pos Index of character to search from (default 0).
2735  * @return Index of first occurrence.
2736  *
2737  * Starting from @a __pos, searches forward for a character
2738  * other than @a __c within this string. If found, returns the
2739  * index where it was found. If not found, returns npos.
2740  */
2741  size_type
2742  find_first_not_of(_CharT __c, size_type __pos = 0) const
2743  _GLIBCXX_NOEXCEPT;
2744 
2745  /**
2746  * @brief Find last position of a character not in string.
2747  * @param __str String containing characters to avoid.
2748  * @param __pos Index of character to search back from (default end).
2749  * @return Index of last occurrence.
2750  *
2751  * Starting from @a __pos, searches backward for a character
2752  * not contained in @a __str within this string. If found,
2753  * returns the index where it was found. If not found, returns
2754  * npos.
2755  */
2756  size_type
2757  find_last_not_of(const basic_string& __str, size_type __pos = npos) const
2758  _GLIBCXX_NOEXCEPT
2759  { return this->find_last_not_of(__str.data(), __pos, __str.size()); }
2760 
2761 #if __cplusplus >= 201703L
2762  /**
2763  * @brief Find last position of a character not in a string_view.
2764  * @param __svt An object convertible to string_view containing
2765  * characters to avoid.
2766  * @param __pos Index of character to search back from (default end).
2767  * @return Index of last occurrence.
2768  */
2769  template<typename _Tp>
2770  _If_sv<_Tp, size_type>
2771  find_last_not_of(const _Tp& __svt, size_type __pos = npos) const
2772  noexcept(is_same<_Tp, __sv_type>::value)
2773  {
2774  __sv_type __sv = __svt;
2775  return this->find_last_not_of(__sv.data(), __pos, __sv.size());
2776  }
2777 #endif // C++17
2778 
2779  /**
2780  * @brief Find last position of a character not in C substring.
2781  * @param __s C string containing characters to avoid.
2782  * @param __pos Index of character to search back from.
2783  * @param __n Number of characters from s to consider.
2784  * @return Index of last occurrence.
2785  *
2786  * Starting from @a __pos, searches backward for a character not
2787  * contained in the first @a __n characters of @a __s within this string.
2788  * If found, returns the index where it was found. If not found,
2789  * returns npos.
2790  */
2791  size_type
2792  find_last_not_of(const _CharT* __s, size_type __pos,
2793  size_type __n) const _GLIBCXX_NOEXCEPT;
2794  /**
2795  * @brief Find last position of a character not in C string.
2796  * @param __s C string containing characters to avoid.
2797  * @param __pos Index of character to search back from (default end).
2798  * @return Index of last occurrence.
2799  *
2800  * Starting from @a __pos, searches backward for a character
2801  * not contained in @a __s within this string. If found,
2802  * returns the index where it was found. If not found, returns
2803  * npos.
2804  */
2805  size_type
2806  find_last_not_of(const _CharT* __s, size_type __pos = npos) const
2807  _GLIBCXX_NOEXCEPT
2808  {
2809  __glibcxx_requires_string(__s);
2810  return this->find_last_not_of(__s, __pos, traits_type::length(__s));
2811  }
2812 
2813  /**
2814  * @brief Find last position of a different character.
2815  * @param __c Character to avoid.
2816  * @param __pos Index of character to search back from (default end).
2817  * @return Index of last occurrence.
2818  *
2819  * Starting from @a __pos, searches backward for a character other than
2820  * @a __c within this string. If found, returns the index where it was
2821  * found. If not found, returns npos.
2822  */
2823  size_type
2824  find_last_not_of(_CharT __c, size_type __pos = npos) const
2825  _GLIBCXX_NOEXCEPT;
2826 
2827  /**
2828  * @brief Get a substring.
2829  * @param __pos Index of first character (default 0).
2830  * @param __n Number of characters in substring (default remainder).
2831  * @return The new string.
2832  * @throw std::out_of_range If __pos > size().
2833  *
2834  * Construct and return a new string using the @a __n
2835  * characters starting at @a __pos. If the string is too
2836  * short, use the remainder of the characters. If @a __pos is
2837  * beyond the end of the string, out_of_range is thrown.
2838  */
2839  basic_string
2840  substr(size_type __pos = 0, size_type __n = npos) const
2841  { return basic_string(*this,
2842  _M_check(__pos, "basic_string::substr"), __n); }
2843 
2844  /**
2845  * @brief Compare to a string.
2846  * @param __str String to compare against.
2847  * @return Integer < 0, 0, or > 0.
2848  *
2849  * Returns an integer < 0 if this string is ordered before @a
2850  * __str, 0 if their values are equivalent, or > 0 if this
2851  * string is ordered after @a __str. Determines the effective
2852  * length rlen of the strings to compare as the smallest of
2853  * size() and str.size(). The function then compares the two
2854  * strings by calling traits::compare(data(), str.data(),rlen).
2855  * If the result of the comparison is nonzero returns it,
2856  * otherwise the shorter one is ordered first.
2857  */
2858  int
2859  compare(const basic_string& __str) const
2860  {
2861  const size_type __size = this->size();
2862  const size_type __osize = __str.size();
2863  const size_type __len = std::min(__size, __osize);
2864 
2865  int __r = traits_type::compare(_M_data(), __str.data(), __len);
2866  if (!__r)
2867  __r = _S_compare(__size, __osize);
2868  return __r;
2869  }
2870 
2871 #if __cplusplus >= 201703L
2872  /**
2873  * @brief Compare to a string_view.
2874  * @param __svt An object convertible to string_view to compare against.
2875  * @return Integer < 0, 0, or > 0.
2876  */
2877  template<typename _Tp>
2878  _If_sv<_Tp, int>
2879  compare(const _Tp& __svt) const
2880  noexcept(is_same<_Tp, __sv_type>::value)
2881  {
2882  __sv_type __sv = __svt;
2883  const size_type __size = this->size();
2884  const size_type __osize = __sv.size();
2885  const size_type __len = std::min(__size, __osize);
2886 
2887  int __r = traits_type::compare(_M_data(), __sv.data(), __len);
2888  if (!__r)
2889  __r = _S_compare(__size, __osize);
2890  return __r;
2891  }
2892 
2893  /**
2894  * @brief Compare to a string_view.
2895  * @param __pos A position in the string to start comparing from.
2896  * @param __n The number of characters to compare.
2897  * @param __svt An object convertible to string_view to compare
2898  * against.
2899  * @return Integer < 0, 0, or > 0.
2900  */
2901  template<typename _Tp>
2902  _If_sv<_Tp, int>
2903  compare(size_type __pos, size_type __n, const _Tp& __svt) const
2904  noexcept(is_same<_Tp, __sv_type>::value)
2905  {
2906  __sv_type __sv = __svt;
2907  return __sv_type(*this).substr(__pos, __n).compare(__sv);
2908  }
2909 
2910  /**
2911  * @brief Compare to a string_view.
2912  * @param __pos1 A position in the string to start comparing from.
2913  * @param __n1 The number of characters to compare.
2914  * @param __svt An object convertible to string_view to compare
2915  * against.
2916  * @param __pos2 A position in the string_view to start comparing from.
2917  * @param __n2 The number of characters to compare.
2918  * @return Integer < 0, 0, or > 0.
2919  */
2920  template<typename _Tp>
2921  _If_sv<_Tp, int>
2922  compare(size_type __pos1, size_type __n1, const _Tp& __svt,
2923  size_type __pos2, size_type __n2 = npos) const
2924  noexcept(is_same<_Tp, __sv_type>::value)
2925  {
2926  __sv_type __sv = __svt;
2927  return __sv_type(*this)
2928  .substr(__pos1, __n1).compare(__sv.substr(__pos2, __n2));
2929  }
2930 #endif // C++17
2931 
2932  /**
2933  * @brief Compare substring to a string.
2934  * @param __pos Index of first character of substring.
2935  * @param __n Number of characters in substring.
2936  * @param __str String to compare against.
2937  * @return Integer < 0, 0, or > 0.
2938  *
2939  * Form the substring of this string from the @a __n characters
2940  * starting at @a __pos. Returns an integer < 0 if the
2941  * substring is ordered before @a __str, 0 if their values are
2942  * equivalent, or > 0 if the substring is ordered after @a
2943  * __str. Determines the effective length rlen of the strings
2944  * to compare as the smallest of the length of the substring
2945  * and @a __str.size(). The function then compares the two
2946  * strings by calling
2947  * traits::compare(substring.data(),str.data(),rlen). If the
2948  * result of the comparison is nonzero returns it, otherwise
2949  * the shorter one is ordered first.
2950  */
2951  int
2952  compare(size_type __pos, size_type __n, const basic_string& __str) const;
2953 
2954  /**
2955  * @brief Compare substring to a substring.
2956  * @param __pos1 Index of first character of substring.
2957  * @param __n1 Number of characters in substring.
2958  * @param __str String to compare against.
2959  * @param __pos2 Index of first character of substring of str.
2960  * @param __n2 Number of characters in substring of str.
2961  * @return Integer < 0, 0, or > 0.
2962  *
2963  * Form the substring of this string from the @a __n1
2964  * characters starting at @a __pos1. Form the substring of @a
2965  * __str from the @a __n2 characters starting at @a __pos2.
2966  * Returns an integer < 0 if this substring is ordered before
2967  * the substring of @a __str, 0 if their values are equivalent,
2968  * or > 0 if this substring is ordered after the substring of
2969  * @a __str. Determines the effective length rlen of the
2970  * strings to compare as the smallest of the lengths of the
2971  * substrings. The function then compares the two strings by
2972  * calling
2973  * traits::compare(substring.data(),str.substr(pos2,n2).data(),rlen).
2974  * If the result of the comparison is nonzero returns it,
2975  * otherwise the shorter one is ordered first.
2976  */
2977  int
2978  compare(size_type __pos1, size_type __n1, const basic_string& __str,
2979  size_type __pos2, size_type __n2 = npos) const;
2980 
2981  /**
2982  * @brief Compare to a C string.
2983  * @param __s C string to compare against.
2984  * @return Integer < 0, 0, or > 0.
2985  *
2986  * Returns an integer < 0 if this string is ordered before @a __s, 0 if
2987  * their values are equivalent, or > 0 if this string is ordered after
2988  * @a __s. Determines the effective length rlen of the strings to
2989  * compare as the smallest of size() and the length of a string
2990  * constructed from @a __s. The function then compares the two strings
2991  * by calling traits::compare(data(),s,rlen). If the result of the
2992  * comparison is nonzero returns it, otherwise the shorter one is
2993  * ordered first.
2994  */
2995  int
2996  compare(const _CharT* __s) const _GLIBCXX_NOEXCEPT;
2997 
2998  // _GLIBCXX_RESOLVE_LIB_DEFECTS
2999  // 5 String::compare specification questionable
3000  /**
3001  * @brief Compare substring to a C string.
3002  * @param __pos Index of first character of substring.
3003  * @param __n1 Number of characters in substring.
3004  * @param __s C string to compare against.
3005  * @return Integer < 0, 0, or > 0.
3006  *
3007  * Form the substring of this string from the @a __n1
3008  * characters starting at @a pos. Returns an integer < 0 if
3009  * the substring is ordered before @a __s, 0 if their values
3010  * are equivalent, or > 0 if the substring is ordered after @a
3011  * __s. Determines the effective length rlen of the strings to
3012  * compare as the smallest of the length of the substring and
3013  * the length of a string constructed from @a __s. The
3014  * function then compares the two string by calling
3015  * traits::compare(substring.data(),__s,rlen). If the result of
3016  * the comparison is nonzero returns it, otherwise the shorter
3017  * one is ordered first.
3018  */
3019  int
3020  compare(size_type __pos, size_type __n1, const _CharT* __s) const;
3021 
3022  /**
3023  * @brief Compare substring against a character %array.
3024  * @param __pos Index of first character of substring.
3025  * @param __n1 Number of characters in substring.
3026  * @param __s character %array to compare against.
3027  * @param __n2 Number of characters of s.
3028  * @return Integer < 0, 0, or > 0.
3029  *
3030  * Form the substring of this string from the @a __n1
3031  * characters starting at @a __pos. Form a string from the
3032  * first @a __n2 characters of @a __s. Returns an integer < 0
3033  * if this substring is ordered before the string from @a __s,
3034  * 0 if their values are equivalent, or > 0 if this substring
3035  * is ordered after the string from @a __s. Determines the
3036  * effective length rlen of the strings to compare as the
3037  * smallest of the length of the substring and @a __n2. The
3038  * function then compares the two strings by calling
3039  * traits::compare(substring.data(),s,rlen). If the result of
3040  * the comparison is nonzero returns it, otherwise the shorter
3041  * one is ordered first.
3042  *
3043  * NB: s must have at least n2 characters, &apos;\\0&apos; has
3044  * no special meaning.
3045  */
3046  int
3047  compare(size_type __pos, size_type __n1, const _CharT* __s,
3048  size_type __n2) const;
3049 
3050 #if __cplusplus > 201703L
3051  bool
3052  starts_with(basic_string_view<_CharT, _Traits> __x) const noexcept
3053  { return __sv_type(this->data(), this->size()).starts_with(__x); }
3054 
3055  bool
3056  starts_with(_CharT __x) const noexcept
3057  { return __sv_type(this->data(), this->size()).starts_with(__x); }
3058 
3059  bool
3060  starts_with(const _CharT* __x) const noexcept
3061  { return __sv_type(this->data(), this->size()).starts_with(__x); }
3062 
3063  bool
3064  ends_with(basic_string_view<_CharT, _Traits> __x) const noexcept
3065  { return __sv_type(this->data(), this->size()).ends_with(__x); }
3066 
3067  bool
3068  ends_with(_CharT __x) const noexcept
3069  { return __sv_type(this->data(), this->size()).ends_with(__x); }
3070 
3071  bool
3072  ends_with(const _CharT* __x) const noexcept
3073  { return __sv_type(this->data(), this->size()).ends_with(__x); }
3074 #endif // C++20
3075 
3076  // Allow basic_stringbuf::__xfer_bufptrs to call _M_length:
3077  template<typename, typename, typename> friend class basic_stringbuf;
3078  };
3079 _GLIBCXX_END_NAMESPACE_CXX11
3080 #else // !_GLIBCXX_USE_CXX11_ABI
3081  // Reference-counted COW string implentation
3082 
3083  /**
3084  * @class basic_string basic_string.h <string>
3085  * @brief Managing sequences of characters and character-like objects.
3086  *
3087  * @ingroup strings
3088  * @ingroup sequences
3089  *
3090  * @tparam _CharT Type of character
3091  * @tparam _Traits Traits for character type, defaults to
3092  * char_traits<_CharT>.
3093  * @tparam _Alloc Allocator type, defaults to allocator<_CharT>.
3094  *
3095  * Meets the requirements of a <a href="tables.html#65">container</a>, a
3096  * <a href="tables.html#66">reversible container</a>, and a
3097  * <a href="tables.html#67">sequence</a>. Of the
3098  * <a href="tables.html#68">optional sequence requirements</a>, only
3099  * @c push_back, @c at, and @c %array access are supported.
3100  *
3101  * @doctodo
3102  *
3103  *
3104  * Documentation? What's that?
3105  * Nathan Myers <ncm@cantrip.org>.
3106  *
3107  * A string looks like this:
3108  *
3109  * @code
3110  * [_Rep]
3111  * _M_length
3112  * [basic_string<char_type>] _M_capacity
3113  * _M_dataplus _M_refcount
3114  * _M_p ----------------> unnamed array of char_type
3115  * @endcode
3116  *
3117  * Where the _M_p points to the first character in the string, and
3118  * you cast it to a pointer-to-_Rep and subtract 1 to get a
3119  * pointer to the header.
3120  *
3121  * This approach has the enormous advantage that a string object
3122  * requires only one allocation. All the ugliness is confined
3123  * within a single %pair of inline functions, which each compile to
3124  * a single @a add instruction: _Rep::_M_data(), and
3125  * string::_M_rep(); and the allocation function which gets a
3126  * block of raw bytes and with room enough and constructs a _Rep
3127  * object at the front.
3128  *
3129  * The reason you want _M_data pointing to the character %array and
3130  * not the _Rep is so that the debugger can see the string
3131  * contents. (Probably we should add a non-inline member to get
3132  * the _Rep for the debugger to use, so users can check the actual
3133  * string length.)
3134  *
3135  * Note that the _Rep object is a POD so that you can have a
3136  * static <em>empty string</em> _Rep object already @a constructed before
3137  * static constructors have run. The reference-count encoding is
3138  * chosen so that a 0 indicates one reference, so you never try to
3139  * destroy the empty-string _Rep object.
3140  *
3141  * All but the last paragraph is considered pretty conventional
3142  * for a C++ string implementation.
3143  */
3144  // 21.3 Template class basic_string
3145  template<typename _CharT, typename _Traits, typename _Alloc>
3147  {
3149  rebind<_CharT>::other _CharT_alloc_type;
3151 
3152  // Types:
3153  public:
3154  typedef _Traits traits_type;
3155  typedef typename _Traits::char_type value_type;
3156  typedef _Alloc allocator_type;
3157  typedef typename _CharT_alloc_traits::size_type size_type;
3158  typedef typename _CharT_alloc_traits::difference_type difference_type;
3159 #if __cplusplus < 201103L
3160  typedef typename _CharT_alloc_type::reference reference;
3161  typedef typename _CharT_alloc_type::const_reference const_reference;
3162 #else
3163  typedef value_type& reference;
3164  typedef const value_type& const_reference;
3165 #endif
3166  typedef typename _CharT_alloc_traits::pointer pointer;
3167  typedef typename _CharT_alloc_traits::const_pointer const_pointer;
3168  typedef __gnu_cxx::__normal_iterator<pointer, basic_string> iterator;
3169  typedef __gnu_cxx::__normal_iterator<const_pointer, basic_string>
3170  const_iterator;
3173 
3174  protected:
3175  // type used for positions in insert, erase etc.
3176  typedef iterator __const_iterator;
3177 
3178  private:
3179  // _Rep: string representation
3180  // Invariants:
3181  // 1. String really contains _M_length + 1 characters: due to 21.3.4
3182  // must be kept null-terminated.
3183  // 2. _M_capacity >= _M_length
3184  // Allocated memory is always (_M_capacity + 1) * sizeof(_CharT).
3185  // 3. _M_refcount has three states:
3186  // -1: leaked, one reference, no ref-copies allowed, non-const.
3187  // 0: one reference, non-const.
3188  // n>0: n + 1 references, operations require a lock, const.
3189  // 4. All fields==0 is an empty string, given the extra storage
3190  // beyond-the-end for a null terminator; thus, the shared
3191  // empty string representation needs no constructor.
3192 
3193  struct _Rep_base
3194  {
3195  size_type _M_length;
3196  size_type _M_capacity;
3197  _Atomic_word _M_refcount;
3198  };
3199 
3200  struct _Rep : _Rep_base
3201  {
3202  // Types:
3204  rebind<char>::other _Raw_bytes_alloc;
3205 
3206  // (Public) Data members:
3207 
3208  // The maximum number of individual char_type elements of an
3209  // individual string is determined by _S_max_size. This is the
3210  // value that will be returned by max_size(). (Whereas npos
3211  // is the maximum number of bytes the allocator can allocate.)
3212  // If one was to divvy up the theoretical largest size string,
3213  // with a terminating character and m _CharT elements, it'd
3214  // look like this:
3215  // npos = sizeof(_Rep) + (m * sizeof(_CharT)) + sizeof(_CharT)
3216  // Solving for m:
3217  // m = ((npos - sizeof(_Rep))/sizeof(CharT)) - 1
3218  // In addition, this implementation quarters this amount.
3219  static const size_type _S_max_size;
3220  static const _CharT _S_terminal;
3221 
3222  // The following storage is init'd to 0 by the linker, resulting
3223  // (carefully) in an empty string with one reference.
3224  static size_type _S_empty_rep_storage[];
3225 
3226  static _Rep&
3227  _S_empty_rep() _GLIBCXX_NOEXCEPT
3228  {
3229  // NB: Mild hack to avoid strict-aliasing warnings. Note that
3230  // _S_empty_rep_storage is never modified and the punning should
3231  // be reasonably safe in this case.
3232  void* __p = reinterpret_cast<void*>(&_S_empty_rep_storage);
3233  return *reinterpret_cast<_Rep*>(__p);
3234  }
3235 
3236  bool
3237  _M_is_leaked() const _GLIBCXX_NOEXCEPT
3238  {
3239 #if defined(__GTHREADS)
3240  // _M_refcount is mutated concurrently by _M_refcopy/_M_dispose,
3241  // so we need to use an atomic load. However, _M_is_leaked
3242  // predicate does not change concurrently (i.e. the string is either
3243  // leaked or not), so a relaxed load is enough.
3244  return __atomic_load_n(&this->_M_refcount, __ATOMIC_RELAXED) < 0;
3245 #else
3246  return this->_M_refcount < 0;
3247 #endif
3248  }
3249 
3250  bool
3251  _M_is_shared() const _GLIBCXX_NOEXCEPT
3252  {
3253 #if defined(__GTHREADS)
3254  // _M_refcount is mutated concurrently by _M_refcopy/_M_dispose,
3255  // so we need to use an atomic load. Another thread can drop last
3256  // but one reference concurrently with this check, so we need this
3257  // load to be acquire to synchronize with release fetch_and_add in
3258  // _M_dispose.
3259  return __atomic_load_n(&this->_M_refcount, __ATOMIC_ACQUIRE) > 0;
3260 #else
3261  return this->_M_refcount > 0;
3262 #endif
3263  }
3264 
3265  void
3266  _M_set_leaked() _GLIBCXX_NOEXCEPT
3267  { this->_M_refcount = -1; }
3268 
3269  void
3270  _M_set_sharable() _GLIBCXX_NOEXCEPT
3271  { this->_M_refcount = 0; }
3272 
3273  void
3274  _M_set_length_and_sharable(size_type __n) _GLIBCXX_NOEXCEPT
3275  {
3276 #if _GLIBCXX_FULLY_DYNAMIC_STRING == 0
3277  if (__builtin_expect(this != &_S_empty_rep(), false))
3278 #endif
3279  {
3280  this->_M_set_sharable(); // One reference.
3281  this->_M_length = __n;
3282  traits_type::assign(this->_M_refdata()[__n], _S_terminal);
3283  // grrr. (per 21.3.4)
3284  // You cannot leave those LWG people alone for a second.
3285  }
3286  }
3287 
3288  _CharT*
3289  _M_refdata() throw()
3290  { return reinterpret_cast<_CharT*>(this + 1); }
3291 
3292  _CharT*
3293  _M_grab(const _Alloc& __alloc1, const _Alloc& __alloc2)
3294  {
3295  return (!_M_is_leaked() && __alloc1 == __alloc2)
3296  ? _M_refcopy() : _M_clone(__alloc1);
3297  }
3298 
3299  // Create & Destroy
3300  static _Rep*
3301  _S_create(size_type, size_type, const _Alloc&);
3302 
3303  void
3304  _M_dispose(const _Alloc& __a) _GLIBCXX_NOEXCEPT
3305  {
3306 #if _GLIBCXX_FULLY_DYNAMIC_STRING == 0
3307  if (__builtin_expect(this != &_S_empty_rep(), false))
3308 #endif
3309  {
3310  // Be race-detector-friendly. For more info see bits/c++config.
3311  _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(&this->_M_refcount);
3312  // Decrement of _M_refcount is acq_rel, because:
3313  // - all but last decrements need to release to synchronize with
3314  // the last decrement that will delete the object.
3315  // - the last decrement needs to acquire to synchronize with
3316  // all the previous decrements.
3317  // - last but one decrement needs to release to synchronize with
3318  // the acquire load in _M_is_shared that will conclude that
3319  // the object is not shared anymore.
3320  if (__gnu_cxx::__exchange_and_add_dispatch(&this->_M_refcount,
3321  -1) <= 0)
3322  {
3323  _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(&this->_M_refcount);
3324  _M_destroy(__a);
3325  }
3326  }
3327  } // XXX MT
3328 
3329  void
3330  _M_destroy(const _Alloc&) throw();
3331 
3332  _CharT*
3333  _M_refcopy() throw()
3334  {
3335 #if _GLIBCXX_FULLY_DYNAMIC_STRING == 0
3336  if (__builtin_expect(this != &_S_empty_rep(), false))
3337 #endif
3338  __gnu_cxx::__atomic_add_dispatch(&this->_M_refcount, 1);
3339  return _M_refdata();
3340  } // XXX MT
3341 
3342  _CharT*
3343  _M_clone(const _Alloc&, size_type __res = 0);
3344  };
3345 
3346  // Use empty-base optimization: http://www.cantrip.org/emptyopt.html
3347  struct _Alloc_hider : _Alloc
3348  {
3349  _Alloc_hider(_CharT* __dat, const _Alloc& __a) _GLIBCXX_NOEXCEPT
3350  : _Alloc(__a), _M_p(__dat) { }
3351 
3352  _CharT* _M_p; // The actual data.
3353  };
3354 
3355  public:
3356  // Data Members (public):
3357  // NB: This is an unsigned type, and thus represents the maximum
3358  // size that the allocator can hold.
3359  /// Value returned by various member functions when they fail.
3360  static const size_type npos = static_cast<size_type>(-1);
3361 
3362  private:
3363  // Data Members (private):
3364  mutable _Alloc_hider _M_dataplus;
3365 
3366  _CharT*
3367  _M_data() const _GLIBCXX_NOEXCEPT
3368  { return _M_dataplus._M_p; }
3369 
3370  _CharT*
3371  _M_data(_CharT* __p) _GLIBCXX_NOEXCEPT
3372  { return (_M_dataplus._M_p = __p); }
3373 
3374  _Rep*
3375  _M_rep() const _GLIBCXX_NOEXCEPT
3376  { return &((reinterpret_cast<_Rep*> (_M_data()))[-1]); }
3377 
3378  // For the internal use we have functions similar to `begin'/`end'
3379  // but they do not call _M_leak.
3380  iterator
3381  _M_ibegin() const _GLIBCXX_NOEXCEPT
3382  { return iterator(_M_data()); }
3383 
3384  iterator
3385  _M_iend() const _GLIBCXX_NOEXCEPT
3386  { return iterator(_M_data() + this->size()); }
3387 
3388  void
3389  _M_leak() // for use in begin() & non-const op[]
3390  {
3391  if (!_M_rep()->_M_is_leaked())
3392  _M_leak_hard();
3393  }
3394 
3395  size_type
3396  _M_check(size_type __pos, const char* __s) const
3397  {
3398  if (__pos > this->size())
3399  __throw_out_of_range_fmt(__N("%s: __pos (which is %zu) > "
3400  "this->size() (which is %zu)"),
3401  __s, __pos, this->size());
3402  return __pos;
3403  }
3404 
3405  void
3406  _M_check_length(size_type __n1, size_type __n2, const char* __s) const
3407  {
3408  if (this->max_size() - (this->size() - __n1) < __n2)
3409  __throw_length_error(__N(__s));
3410  }
3411 
3412  // NB: _M_limit doesn't check for a bad __pos value.
3413  size_type
3414  _M_limit(size_type __pos, size_type __off) const _GLIBCXX_NOEXCEPT
3415  {
3416  const bool __testoff = __off < this->size() - __pos;
3417  return __testoff ? __off : this->size() - __pos;
3418  }
3419 
3420  // True if _Rep and source do not overlap.
3421  bool
3422  _M_disjunct(const _CharT* __s) const _GLIBCXX_NOEXCEPT
3423  {
3424  return (less<const _CharT*>()(__s, _M_data())
3425  || less<const _CharT*>()(_M_data() + this->size(), __s));
3426  }
3427 
3428  // When __n = 1 way faster than the general multichar
3429  // traits_type::copy/move/assign.
3430  static void
3431  _M_copy(_CharT* __d, const _CharT* __s, size_type __n) _GLIBCXX_NOEXCEPT
3432  {
3433  if (__n == 1)
3434  traits_type::assign(*__d, *__s);
3435  else
3436  traits_type::copy(__d, __s, __n);
3437  }
3438 
3439  static void
3440  _M_move(_CharT* __d, const _CharT* __s, size_type __n) _GLIBCXX_NOEXCEPT
3441  {
3442  if (__n == 1)
3443  traits_type::assign(*__d, *__s);
3444  else
3445  traits_type::move(__d, __s, __n);
3446  }
3447 
3448  static void
3449  _M_assign(_CharT* __d, size_type __n, _CharT __c) _GLIBCXX_NOEXCEPT
3450  {
3451  if (__n == 1)
3452  traits_type::assign(*__d, __c);
3453  else
3454  traits_type::assign(__d, __n, __c);
3455  }
3456 
3457  // _S_copy_chars is a separate template to permit specialization
3458  // to optimize for the common case of pointers as iterators.
3459  template<class _Iterator>
3460  static void
3461  _S_copy_chars(_CharT* __p, _Iterator __k1, _Iterator __k2)
3462  {
3463  for (; __k1 != __k2; ++__k1, (void)++__p)
3464  traits_type::assign(*__p, *__k1); // These types are off.
3465  }
3466 
3467  static void
3468  _S_copy_chars(_CharT* __p, iterator __k1, iterator __k2) _GLIBCXX_NOEXCEPT
3469  { _S_copy_chars(__p, __k1.base(), __k2.base()); }
3470 
3471  static void
3472  _S_copy_chars(_CharT* __p, const_iterator __k1, const_iterator __k2)
3473  _GLIBCXX_NOEXCEPT
3474  { _S_copy_chars(__p, __k1.base(), __k2.base()); }
3475 
3476  static void
3477  _S_copy_chars(_CharT* __p, _CharT* __k1, _CharT* __k2) _GLIBCXX_NOEXCEPT
3478  { _M_copy(__p, __k1, __k2 - __k1); }
3479 
3480  static void
3481  _S_copy_chars(_CharT* __p, const _CharT* __k1, const _CharT* __k2)
3482  _GLIBCXX_NOEXCEPT
3483  { _M_copy(__p, __k1, __k2 - __k1); }
3484 
3485  static int
3486  _S_compare(size_type __n1, size_type __n2) _GLIBCXX_NOEXCEPT
3487  {
3488  const difference_type __d = difference_type(__n1 - __n2);
3489 
3490  if (__d > __gnu_cxx::__numeric_traits<int>::__max)
3491  return __gnu_cxx::__numeric_traits<int>::__max;
3492  else if (__d < __gnu_cxx::__numeric_traits<int>::__min)
3493  return __gnu_cxx::__numeric_traits<int>::__min;
3494  else
3495  return int(__d);
3496  }
3497 
3498  void
3499  _M_mutate(size_type __pos, size_type __len1, size_type __len2);
3500 
3501  void
3502  _M_leak_hard();
3503 
3504  static _Rep&
3505  _S_empty_rep() _GLIBCXX_NOEXCEPT
3506  { return _Rep::_S_empty_rep(); }
3507 
3508 #if __cplusplus >= 201703L
3509  // A helper type for avoiding boiler-plate.
3510  typedef basic_string_view<_CharT, _Traits> __sv_type;
3511 
3512  template<typename _Tp, typename _Res>
3513  using _If_sv = enable_if_t<
3514  __and_<is_convertible<const _Tp&, __sv_type>,
3515  __not_<is_convertible<const _Tp*, const basic_string*>>,
3516  __not_<is_convertible<const _Tp&, const _CharT*>>>::value,
3517  _Res>;
3518 
3519  // Allows an implicit conversion to __sv_type.
3520  static __sv_type
3521  _S_to_string_view(__sv_type __svt) noexcept
3522  { return __svt; }
3523 
3524  // Wraps a string_view by explicit conversion and thus
3525  // allows to add an internal constructor that does not
3526  // participate in overload resolution when a string_view
3527  // is provided.
3528  struct __sv_wrapper
3529  {
3530  explicit __sv_wrapper(__sv_type __sv) noexcept : _M_sv(__sv) { }
3531  __sv_type _M_sv;
3532  };
3533 
3534  /**
3535  * @brief Only internally used: Construct string from a string view
3536  * wrapper.
3537  * @param __svw string view wrapper.
3538  * @param __a Allocator to use.
3539  */
3540  explicit
3541  basic_string(__sv_wrapper __svw, const _Alloc& __a)
3542  : basic_string(__svw._M_sv.data(), __svw._M_sv.size(), __a) { }
3543 #endif
3544 
3545  public:
3546  // Construct/copy/destroy:
3547  // NB: We overload ctors in some cases instead of using default
3548  // arguments, per 17.4.4.4 para. 2 item 2.
3549 
3550  /**
3551  * @brief Default constructor creates an empty string.
3552  */
3554 #if _GLIBCXX_FULLY_DYNAMIC_STRING == 0
3555  _GLIBCXX_NOEXCEPT
3556  : _M_dataplus(_S_empty_rep()._M_refdata(), _Alloc())
3557 #else
3558  : _M_dataplus(_S_construct(size_type(), _CharT(), _Alloc()), _Alloc())
3559 #endif
3560  { }
3561 
3562  /**
3563  * @brief Construct an empty string using allocator @a a.
3564  */
3565  explicit
3566  basic_string(const _Alloc& __a)
3567  : _M_dataplus(_S_construct(size_type(), _CharT(), __a), __a)
3568  { }
3569 
3570  // NB: per LWG issue 42, semantics different from IS:
3571  /**
3572  * @brief Construct string with copy of value of @a str.
3573  * @param __str Source string.
3574  */
3576  : _M_dataplus(__str._M_rep()->_M_grab(_Alloc(__str.get_allocator()),
3577  __str.get_allocator()),
3578  __str.get_allocator())
3579  { }
3580 
3581  // _GLIBCXX_RESOLVE_LIB_DEFECTS
3582  // 2583. no way to supply an allocator for basic_string(str, pos)
3583  /**
3584  * @brief Construct string as copy of a substring.
3585  * @param __str Source string.
3586  * @param __pos Index of first character to copy from.
3587  * @param __a Allocator to use.
3588  */
3589  basic_string(const basic_string& __str, size_type __pos,
3590  const _Alloc& __a = _Alloc());
3591 
3592  /**
3593  * @brief Construct string as copy of a substring.
3594  * @param __str Source string.
3595  * @param __pos Index of first character to copy from.
3596  * @param __n Number of characters to copy.
3597  */
3598  basic_string(const basic_string& __str, size_type __pos,
3599  size_type __n);
3600  /**
3601  * @brief Construct string as copy of a substring.
3602  * @param __str Source string.
3603  * @param __pos Index of first character to copy from.
3604  * @param __n Number of characters to copy.
3605  * @param __a Allocator to use.
3606  */
3607  basic_string(const basic_string& __str, size_type __pos,
3608  size_type __n, const _Alloc& __a);
3609 
3610  /**
3611  * @brief Construct string initialized by a character %array.
3612  * @param __s Source character %array.
3613  * @param __n Number of characters to copy.
3614  * @param __a Allocator to use (default is default allocator).
3615  *
3616  * NB: @a __s must have at least @a __n characters, &apos;\\0&apos;
3617  * has no special meaning.
3618  */
3619  basic_string(const _CharT* __s, size_type __n,
3620  const _Alloc& __a = _Alloc())
3621  : _M_dataplus(_S_construct(__s, __s + __n, __a), __a)
3622  { }
3623 
3624  /**
3625  * @brief Construct string as copy of a C string.
3626  * @param __s Source C string.
3627  * @param __a Allocator to use (default is default allocator).
3628  */
3629 #if __cpp_deduction_guides && ! defined _GLIBCXX_DEFINING_STRING_INSTANTIATIONS
3630  // _GLIBCXX_RESOLVE_LIB_DEFECTS
3631  // 3076. basic_string CTAD ambiguity
3632  template<typename = _RequireAllocator<_Alloc>>
3633 #endif
3634  basic_string(const _CharT* __s, const _Alloc& __a = _Alloc())
3635  : _M_dataplus(_S_construct(__s, __s ? __s + traits_type::length(__s) :
3636  __s + npos, __a), __a)
3637  { }
3638 
3639  /**
3640  * @brief Construct string as multiple characters.
3641  * @param __n Number of characters.
3642  * @param __c Character to use.
3643  * @param __a Allocator to use (default is default allocator).
3644  */
3645  basic_string(size_type __n, _CharT __c, const _Alloc& __a = _Alloc())
3646  : _M_dataplus(_S_construct(__n, __c, __a), __a)
3647  { }
3648 
3649 #if __cplusplus >= 201103L
3650  /**
3651  * @brief Move construct string.
3652  * @param __str Source string.
3653  *
3654  * The newly-created string contains the exact contents of @a __str.
3655  * @a __str is a valid, but unspecified string.
3656  */
3658 #if _GLIBCXX_FULLY_DYNAMIC_STRING == 0
3659  noexcept // FIXME C++11: should always be noexcept.
3660 #endif
3661  : _M_dataplus(std::move(__str._M_dataplus))
3662  {
3663 #if _GLIBCXX_FULLY_DYNAMIC_STRING == 0
3664  __str._M_data(_S_empty_rep()._M_refdata());
3665 #else
3666  __str._M_data(_S_construct(size_type(), _CharT(), get_allocator()));
3667 #endif
3668  }
3669 
3670  /**
3671  * @brief Construct string from an initializer %list.
3672  * @param __l std::initializer_list of characters.
3673  * @param __a Allocator to use (default is default allocator).
3674  */
3675  basic_string(initializer_list<_CharT> __l, const _Alloc& __a = _Alloc())
3676  : _M_dataplus(_S_construct(__l.begin(), __l.end(), __a), __a)
3677  { }
3678 
3679  basic_string(const basic_string& __str, const _Alloc& __a)
3680  : _M_dataplus(__str._M_rep()->_M_grab(__a, __str.get_allocator()), __a)
3681  { }
3682 
3683  basic_string(basic_string&& __str, const _Alloc& __a)
3684  : _M_dataplus(__str._M_data(), __a)
3685  {
3686  if (__a == __str.get_allocator())
3687  {
3688 #if _GLIBCXX_FULLY_DYNAMIC_STRING == 0
3689  __str._M_data(_S_empty_rep()._M_refdata());
3690 #else
3691  __str._M_data(_S_construct(size_type(), _CharT(), __a));
3692 #endif
3693  }
3694  else
3695  _M_dataplus._M_p = _S_construct(__str.begin(), __str.end(), __a);
3696  }
3697 #endif // C++11
3698 
3699  /**
3700  * @brief Construct string as copy of a range.
3701  * @param __beg Start of range.
3702  * @param __end End of range.
3703  * @param __a Allocator to use (default is default allocator).
3704  */
3705  template<class _InputIterator>
3706  basic_string(_InputIterator __beg, _InputIterator __end,
3707  const _Alloc& __a = _Alloc())
3708  : _M_dataplus(_S_construct(__beg, __end, __a), __a)
3709  { }
3710 
3711 #if __cplusplus >= 201703L
3712  /**
3713  * @brief Construct string from a substring of a string_view.
3714  * @param __t Source object convertible to string view.
3715  * @param __pos The index of the first character to copy from __t.
3716  * @param __n The number of characters to copy from __t.
3717  * @param __a Allocator to use.
3718  */
3719  template<typename _Tp, typename = _If_sv<_Tp, void>>
3720  basic_string(const _Tp& __t, size_type __pos, size_type __n,
3721  const _Alloc& __a = _Alloc())
3722  : basic_string(_S_to_string_view(__t).substr(__pos, __n), __a) { }
3723 
3724  /**
3725  * @brief Construct string from a string_view.
3726  * @param __t Source object convertible to string view.
3727  * @param __a Allocator to use (default is default allocator).
3728  */
3729  template<typename _Tp, typename = _If_sv<_Tp, void>>
3730  explicit
3731  basic_string(const _Tp& __t, const _Alloc& __a = _Alloc())
3732  : basic_string(__sv_wrapper(_S_to_string_view(__t)), __a) { }
3733 #endif // C++17
3734 
3735  /**
3736  * @brief Destroy the string instance.
3737  */
3738  ~basic_string() _GLIBCXX_NOEXCEPT
3739  { _M_rep()->_M_dispose(this->get_allocator()); }
3740 
3741  /**
3742  * @brief Assign the value of @a str to this string.
3743  * @param __str Source string.
3744  */
3745  basic_string&
3746  operator=(const basic_string& __str)
3747  { return this->assign(__str); }
3748 
3749  /**
3750  * @brief Copy contents of @a s into this string.
3751  * @param __s Source null-terminated string.
3752  */
3753  basic_string&
3754  operator=(const _CharT* __s)
3755  { return this->assign(__s); }
3756 
3757  /**
3758  * @brief Set value to string of length 1.
3759  * @param __c Source character.
3760  *
3761  * Assigning to a character makes this string length 1 and
3762  * (*this)[0] == @a c.
3763  */
3764  basic_string&
3765  operator=(_CharT __c)
3766  {
3767  this->assign(1, __c);
3768  return *this;
3769  }
3770 
3771 #if __cplusplus >= 201103L
3772  /**
3773  * @brief Move assign the value of @a str to this string.
3774  * @param __str Source string.
3775  *
3776  * The contents of @a str are moved into this string (without copying).
3777  * @a str is a valid, but unspecified string.
3778  */
3779  basic_string&
3782  {
3783  // NB: DR 1204.
3784  this->swap(__str);
3785  return *this;
3786  }
3787 
3788  /**
3789  * @brief Set value to string constructed from initializer %list.
3790  * @param __l std::initializer_list.
3791  */
3792  basic_string&
3794  {
3795  this->assign(__l.begin(), __l.size());
3796  return *this;
3797  }
3798 #endif // C++11
3799 
3800 #if __cplusplus >= 201703L
3801  /**
3802  * @brief Set value to string constructed from a string_view.
3803  * @param __svt An object convertible to string_view.
3804  */
3805  template<typename _Tp>
3806  _If_sv<_Tp, basic_string&>
3807  operator=(const _Tp& __svt)
3808  { return this->assign(__svt); }
3809 
3810  /**
3811  * @brief Convert to a string_view.
3812  * @return A string_view.
3813  */
3814  operator __sv_type() const noexcept
3815  { return __sv_type(data(), size()); }
3816 #endif // C++17
3817 
3818  // Iterators:
3819  /**
3820  * Returns a read/write iterator that points to the first character in
3821  * the %string. Unshares the string.
3822  */
3823  iterator
3824  begin() // FIXME C++11: should be noexcept.
3825  {
3826  _M_leak();
3827  return iterator(_M_data());
3828  }
3829 
3830  /**
3831  * Returns a read-only (constant) iterator that points to the first
3832  * character in the %string.
3833  */
3834  const_iterator
3835  begin() const _GLIBCXX_NOEXCEPT
3836  { return const_iterator(_M_data()); }
3837 
3838  /**
3839  * Returns a read/write iterator that points one past the last
3840  * character in the %string. Unshares the string.
3841  */
3842  iterator
3843  end() // FIXME C++11: should be noexcept.
3844  {
3845  _M_leak();
3846  return iterator(_M_data() + this->size());
3847  }
3848 
3849  /**
3850  * Returns a read-only (constant) iterator that points one past the
3851  * last character in the %string.
3852  */
3853  const_iterator
3854  end() const _GLIBCXX_NOEXCEPT
3855  { return const_iterator(_M_data() + this->size()); }
3856 
3857  /**
3858  * Returns a read/write reverse iterator that points to the last
3859  * character in the %string. Iteration is done in reverse element
3860  * order. Unshares the string.
3861  */
3862  reverse_iterator
3863  rbegin() // FIXME C++11: should be noexcept.
3864  { return reverse_iterator(this->end()); }
3865 
3866  /**
3867  * Returns a read-only (constant) reverse iterator that points
3868  * to the last character in the %string. Iteration is done in
3869  * reverse element order.
3870  */
3871  const_reverse_iterator
3872  rbegin() const _GLIBCXX_NOEXCEPT
3873  { return const_reverse_iterator(this->end()); }
3874 
3875  /**
3876  * Returns a read/write reverse iterator that points to one before the
3877  * first character in the %string. Iteration is done in reverse
3878  * element order. Unshares the string.
3879  */
3880  reverse_iterator
3881  rend() // FIXME C++11: should be noexcept.
3882  { return reverse_iterator(this->begin()); }
3883 
3884  /**
3885  * Returns a read-only (constant) reverse iterator that points
3886  * to one before the first character in the %string. Iteration
3887  * is done in reverse element order.
3888  */
3889  const_reverse_iterator
3890  rend() const _GLIBCXX_NOEXCEPT
3891  { return const_reverse_iterator(this->begin()); }
3892 
3893 #if __cplusplus >= 201103L
3894  /**
3895  * Returns a read-only (constant) iterator that points to the first
3896  * character in the %string.
3897  */
3898  const_iterator
3899  cbegin() const noexcept
3900  { return const_iterator(this->_M_data()); }
3901 
3902  /**
3903  * Returns a read-only (constant) iterator that points one past the
3904  * last character in the %string.
3905  */
3906  const_iterator
3907  cend() const noexcept
3908  { return const_iterator(this->_M_data() + this->size()); }
3909 
3910  /**
3911  * Returns a read-only (constant) reverse iterator that points
3912  * to the last character in the %string. Iteration is done in
3913  * reverse element order.
3914  */
3915  const_reverse_iterator
3916  crbegin() const noexcept
3917  { return const_reverse_iterator(this->end()); }
3918 
3919  /**
3920  * Returns a read-only (constant) reverse iterator that points
3921  * to one before the first character in the %string. Iteration
3922  * is done in reverse element order.
3923  */
3924  const_reverse_iterator
3925  crend() const noexcept
3926  { return const_reverse_iterator(this->begin()); }
3927 #endif
3928 
3929  public:
3930  // Capacity:
3931  /// Returns the number of characters in the string, not including any
3932  /// null-termination.
3933  size_type
3934  size() const _GLIBCXX_NOEXCEPT
3935  { return _M_rep()->_M_length; }
3936 
3937  /// Returns the number of characters in the string, not including any
3938  /// null-termination.
3939  size_type
3940  length() const _GLIBCXX_NOEXCEPT
3941  { return _M_rep()->_M_length; }
3942 
3943  /// Returns the size() of the largest possible %string.
3944  size_type
3945  max_size() const _GLIBCXX_NOEXCEPT
3946  { return _Rep::_S_max_size; }
3947 
3948  /**
3949  * @brief Resizes the %string to the specified number of characters.
3950  * @param __n Number of characters the %string should contain.
3951  * @param __c Character to fill any new elements.
3952  *
3953  * This function will %resize the %string to the specified
3954  * number of characters. If the number is smaller than the
3955  * %string's current size the %string is truncated, otherwise
3956  * the %string is extended and new elements are %set to @a __c.
3957  */
3958  void
3959  resize(size_type __n, _CharT __c);
3960 
3961  /**
3962  * @brief Resizes the %string to the specified number of characters.
3963  * @param __n Number of characters the %string should contain.
3964  *
3965  * This function will resize the %string to the specified length. If
3966  * the new size is smaller than the %string's current size the %string
3967  * is truncated, otherwise the %string is extended and new characters
3968  * are default-constructed. For basic types such as char, this means
3969  * setting them to 0.
3970  */
3971  void
3972  resize(size_type __n)
3973  { this->resize(__n, _CharT()); }
3974 
3975 #if __cplusplus >= 201103L
3976 #pragma GCC diagnostic push
3977 #pragma GCC diagnostic ignored "-Wdeprecated-declarations"
3978  /// A non-binding request to reduce capacity() to size().
3979  void
3980  shrink_to_fit() noexcept
3981  { reserve(); }
3982 #pragma GCC diagnostic pop
3983 #endif
3984 
3985  /**
3986  * Returns the total number of characters that the %string can hold
3987  * before needing to allocate more memory.
3988  */
3989  size_type
3990  capacity() const _GLIBCXX_NOEXCEPT
3991  { return _M_rep()->_M_capacity; }
3992 
3993  /**
3994  * @brief Attempt to preallocate enough memory for specified number of
3995  * characters.
3996  * @param __res_arg Number of characters required.
3997  * @throw std::length_error If @a __res_arg exceeds @c max_size().
3998  *
3999  * This function attempts to reserve enough memory for the
4000  * %string to hold the specified number of characters. If the
4001  * number requested is more than max_size(), length_error is
4002  * thrown.
4003  *
4004  * The advantage of this function is that if optimal code is a
4005  * necessity and the user can determine the string length that will be
4006  * required, the user can reserve the memory in %advance, and thus
4007  * prevent a possible reallocation of memory and copying of %string
4008  * data.
4009  */
4010  void
4011  reserve(size_type __res_arg);
4012 
4013  /// Equivalent to shrink_to_fit().
4014 #if __cplusplus > 201703L
4015  [[deprecated("use shrink_to_fit() instead")]]
4016 #endif
4017  void
4018  reserve();
4019 
4020  /**
4021  * Erases the string, making it empty.
4022  */
4023 #if _GLIBCXX_FULLY_DYNAMIC_STRING == 0
4024  void
4025  clear() _GLIBCXX_NOEXCEPT
4026  {
4027  if (_M_rep()->_M_is_shared())
4028  {
4029  _M_rep()->_M_dispose(this->get_allocator());
4030  _M_data(_S_empty_rep()._M_refdata());
4031  }
4032  else
4033  _M_rep()->_M_set_length_and_sharable(0);
4034  }
4035 #else
4036  // PR 56166: this should not throw.
4037  void
4038  clear()
4039  { _M_mutate(0, this->size(), 0); }
4040 #endif
4041 
4042  /**
4043  * Returns true if the %string is empty. Equivalent to
4044  * <code>*this == ""</code>.
4045  */
4046  _GLIBCXX_NODISCARD bool
4047  empty() const _GLIBCXX_NOEXCEPT
4048  { return this->size() == 0; }
4049 
4050  // Element access:
4051  /**
4052  * @brief Subscript access to the data contained in the %string.
4053  * @param __pos The index of the character to access.
4054  * @return Read-only (constant) reference to the character.
4055  *
4056  * This operator allows for easy, array-style, data access.
4057  * Note that data access with this operator is unchecked and
4058  * out_of_range lookups are not defined. (For checked lookups
4059  * see at().)
4060  */
4061  const_reference
4062  operator[] (size_type __pos) const _GLIBCXX_NOEXCEPT
4063  {
4064  __glibcxx_assert(__pos <= size());
4065  return _M_data()[__pos];
4066  }
4067 
4068  /**
4069  * @brief Subscript access to the data contained in the %string.
4070  * @param __pos The index of the character to access.
4071  * @return Read/write reference to the character.
4072  *
4073  * This operator allows for easy, array-style, data access.
4074  * Note that data access with this operator is unchecked and
4075  * out_of_range lookups are not defined. (For checked lookups
4076  * see at().) Unshares the string.
4077  */
4078  reference
4079  operator[](size_type __pos)
4080  {
4081  // Allow pos == size() both in C++98 mode, as v3 extension,
4082  // and in C++11 mode.
4083  __glibcxx_assert(__pos <= size());
4084  // In pedantic mode be strict in C++98 mode.
4085  _GLIBCXX_DEBUG_PEDASSERT(__cplusplus >= 201103L || __pos < size());
4086  _M_leak();
4087  return _M_data()[__pos];
4088  }
4089 
4090  /**
4091  * @brief Provides access to the data contained in the %string.
4092  * @param __n The index of the character to access.
4093  * @return Read-only (const) reference to the character.
4094  * @throw std::out_of_range If @a n is an invalid index.
4095  *
4096  * This function provides for safer data access. The parameter is
4097  * first checked that it is in the range of the string. The function
4098  * throws out_of_range if the check fails.
4099  */
4100  const_reference
4101  at(size_type __n) const
4102  {
4103  if (__n >= this->size())
4104  __throw_out_of_range_fmt(__N("basic_string::at: __n "
4105  "(which is %zu) >= this->size() "
4106  "(which is %zu)"),
4107  __n, this->size());
4108  return _M_data()[__n];
4109  }
4110 
4111  /**
4112  * @brief Provides access to the data contained in the %string.
4113  * @param __n The index of the character to access.
4114  * @return Read/write reference to the character.
4115  * @throw std::out_of_range If @a n is an invalid index.
4116  *
4117  * This function provides for safer data access. The parameter is
4118  * first checked that it is in the range of the string. The function
4119  * throws out_of_range if the check fails. Success results in
4120  * unsharing the string.
4121  */
4122  reference
4123  at(size_type __n)
4124  {
4125  if (__n >= size())
4126  __throw_out_of_range_fmt(__N("basic_string::at: __n "
4127  "(which is %zu) >= this->size() "
4128  "(which is %zu)"),
4129  __n, this->size());
4130  _M_leak();
4131  return _M_data()[__n];
4132  }
4133 
4134 #if __cplusplus >= 201103L
4135  /**
4136  * Returns a read/write reference to the data at the first
4137  * element of the %string.
4138  */
4139  reference
4141  {
4142  __glibcxx_assert(!empty());
4143  return operator[](0);
4144  }
4145 
4146  /**
4147  * Returns a read-only (constant) reference to the data at the first
4148  * element of the %string.
4149  */
4150  const_reference
4151  front() const noexcept
4152  {
4153  __glibcxx_assert(!empty());
4154  return operator[](0);
4155  }
4156 
4157  /**
4158  * Returns a read/write reference to the data at the last
4159  * element of the %string.
4160  */
4161  reference
4163  {
4164  __glibcxx_assert(!empty());
4165  return operator[](this->size() - 1);
4166  }
4167 
4168  /**
4169  * Returns a read-only (constant) reference to the data at the
4170  * last element of the %string.
4171  */
4172  const_reference
4173  back() const noexcept
4174  {
4175  __glibcxx_assert(!empty());
4176  return operator[](this->size() - 1);
4177  }
4178 #endif
4179 
4180  // Modifiers:
4181  /**
4182  * @brief Append a string to this string.
4183  * @param __str The string to append.
4184  * @return Reference to this string.
4185  */
4186  basic_string&
4187  operator+=(const basic_string& __str)
4188  { return this->append(__str); }
4189 
4190  /**
4191  * @brief Append a C string.
4192  * @param __s The C string to append.
4193  * @return Reference to this string.
4194  */
4195  basic_string&
4196  operator+=(const _CharT* __s)
4197  { return this->append(__s); }
4198 
4199  /**
4200  * @brief Append a character.
4201  * @param __c The character to append.
4202  * @return Reference to this string.
4203  */
4204  basic_string&
4205  operator+=(_CharT __c)
4206  {
4207  this->push_back(__c);
4208  return *this;
4209  }
4210 
4211 #if __cplusplus >= 201103L
4212  /**
4213  * @brief Append an initializer_list of characters.
4214  * @param __l The initializer_list of characters to be appended.
4215  * @return Reference to this string.
4216  */
4217  basic_string&
4219  { return this->append(__l.begin(), __l.size()); }
4220 #endif // C++11
4221 
4222 #if __cplusplus >= 201703L
4223  /**
4224  * @brief Append a string_view.
4225  * @param __svt The object convertible to string_view to be appended.
4226  * @return Reference to this string.
4227  */
4228  template<typename _Tp>
4229  _If_sv<_Tp, basic_string&>
4230  operator+=(const _Tp& __svt)
4231  { return this->append(__svt); }
4232 #endif // C++17
4233 
4234  /**
4235  * @brief Append a string to this string.
4236  * @param __str The string to append.
4237  * @return Reference to this string.
4238  */
4239  basic_string&
4240  append(const basic_string& __str);
4241 
4242  /**
4243  * @brief Append a substring.
4244  * @param __str The string to append.
4245  * @param __pos Index of the first character of str to append.
4246  * @param __n The number of characters to append.
4247  * @return Reference to this string.
4248  * @throw std::out_of_range if @a __pos is not a valid index.
4249  *
4250  * This function appends @a __n characters from @a __str
4251  * starting at @a __pos to this string. If @a __n is is larger
4252  * than the number of available characters in @a __str, the
4253  * remainder of @a __str is appended.
4254  */
4255  basic_string&
4256  append(const basic_string& __str, size_type __pos, size_type __n = npos);
4257 
4258  /**
4259  * @brief Append a C substring.
4260  * @param __s The C string to append.
4261  * @param __n The number of characters to append.
4262  * @return Reference to this string.
4263  */
4264  basic_string&
4265  append(const _CharT* __s, size_type __n);
4266 
4267  /**
4268  * @brief Append a C string.
4269  * @param __s The C string to append.
4270  * @return Reference to this string.
4271  */
4272  basic_string&
4273  append(const _CharT* __s)
4274  {
4275  __glibcxx_requires_string(__s);
4276  return this->append(__s, traits_type::length(__s));
4277  }
4278 
4279  /**
4280  * @brief Append multiple characters.
4281  * @param __n The number of characters to append.
4282  * @param __c The character to use.
4283  * @return Reference to this string.
4284  *
4285  * Appends __n copies of __c to this string.
4286  */
4287  basic_string&
4288  append(size_type __n, _CharT __c);
4289 
4290 #if __cplusplus >= 201103L
4291  /**
4292  * @brief Append an initializer_list of characters.
4293  * @param __l The initializer_list of characters to append.
4294  * @return Reference to this string.
4295  */
4296  basic_string&
4298  { return this->append(__l.begin(), __l.size()); }
4299 #endif // C++11
4300 
4301  /**
4302  * @brief Append a range of characters.
4303  * @param __first Iterator referencing the first character to append.
4304  * @param __last Iterator marking the end of the range.
4305  * @return Reference to this string.
4306  *
4307  * Appends characters in the range [__first,__last) to this string.
4308  */
4309  template<class _InputIterator>
4310  basic_string&
4311  append(_InputIterator __first, _InputIterator __last)
4312  { return this->replace(_M_iend(), _M_iend(), __first, __last); }
4313 
4314 #if __cplusplus >= 201703L
4315  /**
4316  * @brief Append a string_view.
4317  * @param __svt The object convertible to string_view to be appended.
4318  * @return Reference to this string.
4319  */
4320  template<typename _Tp>
4321  _If_sv<_Tp, basic_string&>
4322  append(const _Tp& __svt)
4323  {
4324  __sv_type __sv = __svt;
4325  return this->append(__sv.data(), __sv.size());
4326  }
4327 
4328  /**
4329  * @brief Append a range of characters from a string_view.
4330  * @param __svt The object convertible to string_view to be appended
4331  * from.
4332  * @param __pos The position in the string_view to append from.
4333  * @param __n The number of characters to append from the string_view.
4334  * @return Reference to this string.
4335  */
4336  template<typename _Tp>
4337  _If_sv<_Tp, basic_string&>
4338  append(const _Tp& __svt, size_type __pos, size_type __n = npos)
4339  {
4340  __sv_type __sv = __svt;
4341  return append(__sv.data()
4342  + std::__sv_check(__sv.size(), __pos, "basic_string::append"),
4343  std::__sv_limit(__sv.size(), __pos, __n));
4344  }
4345 #endif // C++17
4346 
4347  /**
4348  * @brief Append a single character.
4349  * @param __c Character to append.
4350  */
4351  void
4352  push_back(_CharT __c)
4353  {
4354  const size_type __len = 1 + this->size();
4355  if (__len > this->capacity() || _M_rep()->_M_is_shared())
4356  this->reserve(__len);
4357  traits_type::assign(_M_data()[this->size()], __c);
4358  _M_rep()->_M_set_length_and_sharable(__len);
4359  }
4360 
4361  /**
4362  * @brief Set value to contents of another string.
4363  * @param __str Source string to use.
4364  * @return Reference to this string.
4365  */
4366  basic_string&
4367  assign(const basic_string& __str);
4368 
4369 #if __cplusplus >= 201103L
4370  /**
4371  * @brief Set value to contents of another string.
4372  * @param __str Source string to use.
4373  * @return Reference to this string.
4374  *
4375  * This function sets this string to the exact contents of @a __str.
4376  * @a __str is a valid, but unspecified string.
4377  */
4378  basic_string&
4381  {
4382  this->swap(__str);
4383  return *this;
4384  }
4385 #endif // C++11
4386 
4387  /**
4388  * @brief Set value to a substring of a string.
4389  * @param __str The string to use.
4390  * @param __pos Index of the first character of str.
4391  * @param __n Number of characters to use.
4392  * @return Reference to this string.
4393  * @throw std::out_of_range if @a pos is not a valid index.
4394  *
4395  * This function sets this string to the substring of @a __str
4396  * consisting of @a __n characters at @a __pos. If @a __n is
4397  * is larger than the number of available characters in @a
4398  * __str, the remainder of @a __str is used.
4399  */
4400  basic_string&
4401  assign(const basic_string& __str, size_type __pos, size_type __n = npos)
4402  { return this->assign(__str._M_data()
4403  + __str._M_check(__pos, "basic_string::assign"),
4404  __str._M_limit(__pos, __n)); }
4405 
4406  /**
4407  * @brief Set value to a C substring.
4408  * @param __s The C string to use.
4409  * @param __n Number of characters to use.
4410  * @return Reference to this string.
4411  *
4412  * This function sets the value of this string to the first @a __n
4413  * characters of @a __s. If @a __n is is larger than the number of
4414  * available characters in @a __s, the remainder of @a __s is used.
4415  */
4416  basic_string&
4417  assign(const _CharT* __s, size_type __n);
4418 
4419  /**
4420  * @brief Set value to contents of a C string.
4421  * @param __s The C string to use.
4422  * @return Reference to this string.
4423  *
4424  * This function sets the value of this string to the value of @a __s.
4425  * The data is copied, so there is no dependence on @a __s once the
4426  * function returns.
4427  */
4428  basic_string&
4429  assign(const _CharT* __s)
4430  {
4431  __glibcxx_requires_string(__s);
4432  return this->assign(__s, traits_type::length(__s));
4433  }
4434 
4435  /**
4436  * @brief Set value to multiple characters.
4437  * @param __n Length of the resulting string.
4438  * @param __c The character to use.
4439  * @return Reference to this string.
4440  *
4441  * This function sets the value of this string to @a __n copies of
4442  * character @a __c.
4443  */
4444  basic_string&
4445  assign(size_type __n, _CharT __c)
4446  { return _M_replace_aux(size_type(0), this->size(), __n, __c); }
4447 
4448  /**
4449  * @brief Set value to a range of characters.
4450  * @param __first Iterator referencing the first character to append.
4451  * @param __last Iterator marking the end of the range.
4452  * @return Reference to this string.
4453  *
4454  * Sets value of string to characters in the range [__first,__last).
4455  */
4456  template<class _InputIterator>
4457  basic_string&
4458  assign(_InputIterator __first, _InputIterator __last)
4459  { return this->replace(_M_ibegin(), _M_iend(), __first, __last); }
4460 
4461 #if __cplusplus >= 201103L
4462  /**
4463  * @brief Set value to an initializer_list of characters.
4464  * @param __l The initializer_list of characters to assign.
4465  * @return Reference to this string.
4466  */
4467  basic_string&
4469  { return this->assign(__l.begin(), __l.size()); }
4470 #endif // C++11
4471 
4472 #if __cplusplus >= 201703L
4473  /**
4474  * @brief Set value from a string_view.
4475  * @param __svt The source object convertible to string_view.
4476  * @return Reference to this string.
4477  */
4478  template<typename _Tp>
4479  _If_sv<_Tp, basic_string&>
4480  assign(const _Tp& __svt)
4481  {
4482  __sv_type __sv = __svt;
4483  return this->assign(__sv.data(), __sv.size());
4484  }
4485 
4486  /**
4487  * @brief Set value from a range of characters in a string_view.
4488  * @param __svt The source object convertible to string_view.
4489  * @param __pos The position in the string_view to assign from.
4490  * @param __n The number of characters to assign.
4491  * @return Reference to this string.
4492  */
4493  template<typename _Tp>
4494  _If_sv<_Tp, basic_string&>
4495  assign(const _Tp& __svt, size_type __pos, size_type __n = npos)
4496  {
4497  __sv_type __sv = __svt;
4498  return assign(__sv.data()
4499  + std::__sv_check(__sv.size(), __pos, "basic_string::assign"),
4500  std::__sv_limit(__sv.size(), __pos, __n));
4501  }
4502 #endif // C++17
4503 
4504  /**
4505  * @brief Insert multiple characters.
4506  * @param __p Iterator referencing location in string to insert at.
4507  * @param __n Number of characters to insert
4508  * @param __c The character to insert.
4509  * @throw std::length_error If new length exceeds @c max_size().
4510  *
4511  * Inserts @a __n copies of character @a __c starting at the
4512  * position referenced by iterator @a __p. If adding
4513  * characters causes the length to exceed max_size(),
4514  * length_error is thrown. The value of the string doesn't
4515  * change if an error is thrown.
4516  */
4517  void
4518  insert(iterator __p, size_type __n, _CharT __c)
4519  { this->replace(__p, __p, __n, __c); }
4520 
4521  /**
4522  * @brief Insert a range of characters.
4523  * @param __p Iterator referencing location in string to insert at.
4524  * @param __beg Start of range.
4525  * @param __end End of range.
4526  * @throw std::length_error If new length exceeds @c max_size().
4527  *
4528  * Inserts characters in range [__beg,__end). If adding
4529  * characters causes the length to exceed max_size(),
4530  * length_error is thrown. The value of the string doesn't
4531  * change if an error is thrown.
4532  */
4533  template<class _InputIterator>
4534  void
4535  insert(iterator __p, _InputIterator __beg, _InputIterator __end)
4536  { this->replace(__p, __p, __beg, __end); }
4537 
4538 #if __cplusplus >= 201103L
4539  /**
4540  * @brief Insert an initializer_list of characters.
4541  * @param __p Iterator referencing location in string to insert at.
4542  * @param __l The initializer_list of characters to insert.
4543  * @throw std::length_error If new length exceeds @c max_size().
4544  */
4545  void
4547  {
4548  _GLIBCXX_DEBUG_PEDASSERT(__p >= _M_ibegin() && __p <= _M_iend());
4549  this->insert(__p - _M_ibegin(), __l.begin(), __l.size());
4550  }
4551 #endif // C++11
4552 
4553  /**
4554  * @brief Insert value of a string.
4555  * @param __pos1 Position in string to insert at.
4556  * @param __str The string to insert.
4557  * @return Reference to this string.
4558  * @throw std::length_error If new length exceeds @c max_size().
4559  *
4560  * Inserts value of @a __str starting at @a __pos1. If adding
4561  * characters causes the length to exceed max_size(),
4562  * length_error is thrown. The value of the string doesn't
4563  * change if an error is thrown.
4564  */
4565  basic_string&
4566  insert(size_type __pos1, const basic_string& __str)
4567  { return this->insert(__pos1, __str, size_type(0), __str.size()); }
4568 
4569  /**
4570  * @brief Insert a substring.
4571  * @param __pos1 Position in string to insert at.
4572  * @param __str The string to insert.
4573  * @param __pos2 Start of characters in str to insert.
4574  * @param __n Number of characters to insert.
4575  * @return Reference to this string.
4576  * @throw std::length_error If new length exceeds @c max_size().
4577  * @throw std::out_of_range If @a pos1 > size() or
4578  * @a __pos2 > @a str.size().
4579  *
4580  * Starting at @a pos1, insert @a __n character of @a __str
4581  * beginning with @a __pos2. If adding characters causes the
4582  * length to exceed max_size(), length_error is thrown. If @a
4583  * __pos1 is beyond the end of this string or @a __pos2 is
4584  * beyond the end of @a __str, out_of_range is thrown. The
4585  * value of the string doesn't change if an error is thrown.
4586  */
4587  basic_string&
4588  insert(size_type __pos1, const basic_string& __str,
4589  size_type __pos2, size_type __n = npos)
4590  { return this->insert(__pos1, __str._M_data()
4591  + __str._M_check(__pos2, "basic_string::insert"),
4592  __str._M_limit(__pos2, __n)); }
4593 
4594  /**
4595  * @brief Insert a C substring.
4596  * @param __pos Position in string to insert at.
4597  * @param __s The C string to insert.
4598  * @param __n The number of characters to insert.
4599  * @return Reference to this string.
4600  * @throw std::length_error If new length exceeds @c max_size().
4601  * @throw std::out_of_range If @a __pos is beyond the end of this
4602  * string.
4603  *
4604  * Inserts the first @a __n characters of @a __s starting at @a
4605  * __pos. If adding characters causes the length to exceed
4606  * max_size(), length_error is thrown. If @a __pos is beyond
4607  * end(), out_of_range is thrown. The value of the string
4608  * doesn't change if an error is thrown.
4609  */
4610  basic_string&
4611  insert(size_type __pos, const _CharT* __s, size_type __n);
4612 
4613  /**
4614  * @brief Insert a C string.
4615  * @param __pos Position in string to insert at.
4616  * @param __s The C string to insert.
4617  * @return Reference to this string.
4618  * @throw std::length_error If new length exceeds @c max_size().
4619  * @throw std::out_of_range If @a pos is beyond the end of this
4620  * string.
4621  *
4622  * Inserts the first @a n characters of @a __s starting at @a __pos. If
4623  * adding characters causes the length to exceed max_size(),
4624  * length_error is thrown. If @a __pos is beyond end(), out_of_range is
4625  * thrown. The value of the string doesn't change if an error is
4626  * thrown.
4627  */
4628  basic_string&
4629  insert(size_type __pos, const _CharT* __s)
4630  {
4631  __glibcxx_requires_string(__s);
4632  return this->insert(__pos, __s, traits_type::length(__s));
4633  }
4634 
4635  /**
4636  * @brief Insert multiple characters.
4637  * @param __pos Index in string to insert at.
4638  * @param __n Number of characters to insert
4639  * @param __c The character to insert.
4640  * @return Reference to this string.
4641  * @throw std::length_error If new length exceeds @c max_size().
4642  * @throw std::out_of_range If @a __pos is beyond the end of this
4643  * string.
4644  *
4645  * Inserts @a __n copies of character @a __c starting at index
4646  * @a __pos. If adding characters causes the length to exceed
4647  * max_size(), length_error is thrown. If @a __pos > length(),
4648  * out_of_range is thrown. The value of the string doesn't
4649  * change if an error is thrown.
4650  */
4651  basic_string&
4652  insert(size_type __pos, size_type __n, _CharT __c)
4653  { return _M_replace_aux(_M_check(__pos, "basic_string::insert"),
4654  size_type(0), __n, __c); }
4655 
4656  /**
4657  * @brief Insert one character.
4658  * @param __p Iterator referencing position in string to insert at.
4659  * @param __c The character to insert.
4660  * @return Iterator referencing newly inserted char.
4661  * @throw std::length_error If new length exceeds @c max_size().
4662  *
4663  * Inserts character @a __c at position referenced by @a __p.
4664  * If adding character causes the length to exceed max_size(),
4665  * length_error is thrown. If @a __p is beyond end of string,
4666  * out_of_range is thrown. The value of the string doesn't
4667  * change if an error is thrown.
4668  */
4669  iterator
4670  insert(iterator __p, _CharT __c)
4671  {
4672  _GLIBCXX_DEBUG_PEDASSERT(__p >= _M_ibegin() && __p <= _M_iend());
4673  const size_type __pos = __p - _M_ibegin();
4674  _M_replace_aux(__pos, size_type(0), size_type(1), __c);
4675  _M_rep()->_M_set_leaked();
4676  return iterator(_M_data() + __pos);
4677  }
4678 
4679 #if __cplusplus >= 201703L
4680  /**
4681  * @brief Insert a string_view.
4682  * @param __pos Position in string to insert at.
4683  * @param __svt The object convertible to string_view to insert.
4684  * @return Reference to this string.
4685  */
4686  template<typename _Tp>
4687  _If_sv<_Tp, basic_string&>
4688  insert(size_type __pos, const _Tp& __svt)
4689  {
4690  __sv_type __sv = __svt;
4691  return this->insert(__pos, __sv.data(), __sv.size());
4692  }
4693 
4694  /**
4695  * @brief Insert a string_view.
4696  * @param __pos Position in string to insert at.
4697  * @param __svt The object convertible to string_view to insert from.
4698  * @param __pos Position in string_view to insert
4699  * from.
4700  * @param __n The number of characters to insert.
4701  * @return Reference to this string.
4702  */
4703  template<typename _Tp>
4704  _If_sv<_Tp, basic_string&>
4705  insert(size_type __pos1, const _Tp& __svt,
4706  size_type __pos2, size_type __n = npos)
4707  {
4708  __sv_type __sv = __svt;
4709  return this->replace(__pos1, size_type(0), __sv.data()
4710  + std::__sv_check(__sv.size(), __pos2, "basic_string::insert"),
4711  std::__sv_limit(__sv.size(), __pos2, __n));
4712  }
4713 #endif // C++17
4714 
4715  /**
4716  * @brief Remove characters.
4717  * @param __pos Index of first character to remove (default 0).
4718  * @param __n Number of characters to remove (default remainder).
4719  * @return Reference to this string.
4720  * @throw std::out_of_range If @a pos is beyond the end of this
4721  * string.
4722  *
4723  * Removes @a __n characters from this string starting at @a
4724  * __pos. The length of the string is reduced by @a __n. If
4725  * there are < @a __n characters to remove, the remainder of
4726  * the string is truncated. If @a __p is beyond end of string,
4727  * out_of_range is thrown. The value of the string doesn't
4728  * change if an error is thrown.
4729  */
4730  basic_string&
4731  erase(size_type __pos = 0, size_type __n = npos)
4732  {
4733  _M_mutate(_M_check(__pos, "basic_string::erase"),
4734  _M_limit(__pos, __n), size_type(0));
4735  return *this;
4736  }
4737 
4738  /**
4739  * @brief Remove one character.
4740  * @param __position Iterator referencing the character to remove.
4741  * @return iterator referencing same location after removal.
4742  *
4743  * Removes the character at @a __position from this string. The value
4744  * of the string doesn't change if an error is thrown.
4745  */
4746  iterator
4747  erase(iterator __position)
4748  {
4749  _GLIBCXX_DEBUG_PEDASSERT(__position >= _M_ibegin()
4750  && __position < _M_iend());
4751  const size_type __pos = __position - _M_ibegin();
4752  _M_mutate(__pos, size_type(1), size_type(0));
4753  _M_rep()->_M_set_leaked();
4754  return iterator(_M_data() + __pos);
4755  }
4756 
4757  /**
4758  * @brief Remove a range of characters.
4759  * @param __first Iterator referencing the first character to remove.
4760  * @param __last Iterator referencing the end of the range.
4761  * @return Iterator referencing location of first after removal.
4762  *
4763  * Removes the characters in the range [first,last) from this string.
4764  * The value of the string doesn't change if an error is thrown.
4765  */
4766  iterator
4767  erase(iterator __first, iterator __last);
4768 
4769 #if __cplusplus >= 201103L
4770  /**
4771  * @brief Remove the last character.
4772  *
4773  * The string must be non-empty.
4774  */
4775  void
4776  pop_back() // FIXME C++11: should be noexcept.
4777  {
4778  __glibcxx_assert(!empty());
4779  erase(size() - 1, 1);
4780  }
4781 #endif // C++11
4782 
4783  /**
4784  * @brief Replace characters with value from another string.
4785  * @param __pos Index of first character to replace.
4786  * @param __n Number of characters to be replaced.
4787  * @param __str String to insert.
4788  * @return Reference to this string.
4789  * @throw std::out_of_range If @a pos is beyond the end of this
4790  * string.
4791  * @throw std::length_error If new length exceeds @c max_size().
4792  *
4793  * Removes the characters in the range [__pos,__pos+__n) from
4794  * this string. In place, the value of @a __str is inserted.
4795  * If @a __pos is beyond end of string, out_of_range is thrown.
4796  * If the length of the result exceeds max_size(), length_error
4797  * is thrown. The value of the string doesn't change if an
4798  * error is thrown.
4799  */
4800  basic_string&
4801  replace(size_type __pos, size_type __n, const basic_string& __str)
4802  { return this->replace(__pos, __n, __str._M_data(), __str.size()); }
4803 
4804  /**
4805  * @brief Replace characters with value from another string.
4806  * @param __pos1 Index of first character to replace.
4807  * @param __n1 Number of characters to be replaced.
4808  * @param __str String to insert.
4809  * @param __pos2 Index of first character of str to use.
4810  * @param __n2 Number of characters from str to use.
4811  * @return Reference to this string.
4812  * @throw std::out_of_range If @a __pos1 > size() or @a __pos2 >
4813  * __str.size().
4814  * @throw std::length_error If new length exceeds @c max_size().
4815  *
4816  * Removes the characters in the range [__pos1,__pos1 + n) from this
4817  * string. In place, the value of @a __str is inserted. If @a __pos is
4818  * beyond end of string, out_of_range is thrown. If the length of the
4819  * result exceeds max_size(), length_error is thrown. The value of the
4820  * string doesn't change if an error is thrown.
4821  */
4822  basic_string&
4823  replace(size_type __pos1, size_type __n1, const basic_string& __str,
4824  size_type __pos2, size_type __n2 = npos)
4825  { return this->replace(__pos1, __n1, __str._M_data()
4826  + __str._M_check(__pos2, "basic_string::replace"),
4827  __str._M_limit(__pos2, __n2)); }
4828 
4829  /**
4830  * @brief Replace characters with value of a C substring.
4831  * @param __pos Index of first character to replace.
4832  * @param __n1 Number of characters to be replaced.
4833  * @param __s C string to insert.
4834  * @param __n2 Number of characters from @a s to use.
4835  * @return Reference to this string.
4836  * @throw std::out_of_range If @a pos1 > size().
4837  * @throw std::length_error If new length exceeds @c max_size().
4838  *
4839  * Removes the characters in the range [__pos,__pos + __n1)
4840  * from this string. In place, the first @a __n2 characters of
4841  * @a __s are inserted, or all of @a __s if @a __n2 is too large. If
4842  * @a __pos is beyond end of string, out_of_range is thrown. If
4843  * the length of result exceeds max_size(), length_error is
4844  * thrown. The value of the string doesn't change if an error
4845  * is thrown.
4846  */
4847  basic_string&
4848  replace(size_type __pos, size_type __n1, const _CharT* __s,
4849  size_type __n2);
4850 
4851  /**
4852  * @brief Replace characters with value of a C string.
4853  * @param __pos Index of first character to replace.
4854  * @param __n1 Number of characters to be replaced.
4855  * @param __s C string to insert.
4856  * @return Reference to this string.
4857  * @throw std::out_of_range If @a pos > size().
4858  * @throw std::length_error If new length exceeds @c max_size().
4859  *
4860  * Removes the characters in the range [__pos,__pos + __n1)
4861  * from this string. In place, the characters of @a __s are
4862  * inserted. If @a __pos is beyond end of string, out_of_range
4863  * is thrown. If the length of result exceeds max_size(),
4864  * length_error is thrown. The value of the string doesn't
4865  * change if an error is thrown.
4866  */
4867  basic_string&
4868  replace(size_type __pos, size_type __n1, const _CharT* __s)
4869  {
4870  __glibcxx_requires_string(__s);
4871  return this->replace(__pos, __n1, __s, traits_type::length(__s));
4872  }
4873 
4874  /**
4875  * @brief Replace characters with multiple characters.
4876  * @param __pos Index of first character to replace.
4877  * @param __n1 Number of characters to be replaced.
4878  * @param __n2 Number of characters to insert.
4879  * @param __c Character to insert.
4880  * @return Reference to this string.
4881  * @throw std::out_of_range If @a __pos > size().
4882  * @throw std::length_error If new length exceeds @c max_size().
4883  *
4884  * Removes the characters in the range [pos,pos + n1) from this
4885  * string. In place, @a __n2 copies of @a __c are inserted.
4886  * If @a __pos is beyond end of string, out_of_range is thrown.
4887  * If the length of result exceeds max_size(), length_error is
4888  * thrown. The value of the string doesn't change if an error
4889  * is thrown.
4890  */
4891  basic_string&
4892  replace(size_type __pos, size_type __n1, size_type __n2, _CharT __c)
4893  { return _M_replace_aux(_M_check(__pos, "basic_string::replace"),
4894  _M_limit(__pos, __n1), __n2, __c); }
4895 
4896  /**
4897  * @brief Replace range of characters with string.
4898  * @param __i1 Iterator referencing start of range to replace.
4899  * @param __i2 Iterator referencing end of range to replace.
4900  * @param __str String value to insert.
4901  * @return Reference to this string.
4902  * @throw std::length_error If new length exceeds @c max_size().
4903  *
4904  * Removes the characters in the range [__i1,__i2). In place,
4905  * the value of @a __str is inserted. If the length of result
4906  * exceeds max_size(), length_error is thrown. The value of
4907  * the string doesn't change if an error is thrown.
4908  */
4909  basic_string&
4910  replace(iterator __i1, iterator __i2, const basic_string& __str)
4911  { return this->replace(__i1, __i2, __str._M_data(), __str.size()); }
4912 
4913  /**
4914  * @brief Replace range of characters with C substring.
4915  * @param __i1 Iterator referencing start of range to replace.
4916  * @param __i2 Iterator referencing end of range to replace.
4917  * @param __s C string value to insert.
4918  * @param __n Number of characters from s to insert.
4919  * @return Reference to this string.
4920  * @throw std::length_error If new length exceeds @c max_size().
4921  *
4922  * Removes the characters in the range [__i1,__i2). In place,
4923  * the first @a __n characters of @a __s are inserted. If the
4924  * length of result exceeds max_size(), length_error is thrown.
4925  * The value of the string doesn't change if an error is
4926  * thrown.
4927  */
4928  basic_string&
4929  replace(iterator __i1, iterator __i2, const _CharT* __s, size_type __n)
4930  {
4931  _GLIBCXX_DEBUG_PEDASSERT(_M_ibegin() <= __i1 && __i1 <= __i2
4932  && __i2 <= _M_iend());
4933  return this->replace(__i1 - _M_ibegin(), __i2 - __i1, __s, __n);
4934  }
4935 
4936  /**
4937  * @brief Replace range of characters with C string.
4938  * @param __i1 Iterator referencing start of range to replace.
4939  * @param __i2 Iterator referencing end of range to replace.
4940  * @param __s C string value to insert.
4941  * @return Reference to this string.
4942  * @throw std::length_error If new length exceeds @c max_size().
4943  *
4944  * Removes the characters in the range [__i1,__i2). In place,
4945  * the characters of @a __s are inserted. If the length of
4946  * result exceeds max_size(), length_error is thrown. The
4947  * value of the string doesn't change if an error is thrown.
4948  */
4949  basic_string&
4950  replace(iterator __i1, iterator __i2, const _CharT* __s)
4951  {
4952  __glibcxx_requires_string(__s);
4953  return this->replace(__i1, __i2, __s, traits_type::length(__s));
4954  }
4955 
4956  /**
4957  * @brief Replace range of characters with multiple characters
4958  * @param __i1 Iterator referencing start of range to replace.
4959  * @param __i2 Iterator referencing end of range to replace.
4960  * @param __n Number of characters to insert.
4961  * @param __c Character to insert.
4962  * @return Reference to this string.
4963  * @throw std::length_error If new length exceeds @c max_size().
4964  *
4965  * Removes the characters in the range [__i1,__i2). In place,
4966  * @a __n copies of @a __c are inserted. If the length of
4967  * result exceeds max_size(), length_error is thrown. The
4968  * value of the string doesn't change if an error is thrown.
4969  */
4970  basic_string&
4971  replace(iterator __i1, iterator __i2, size_type __n, _CharT __c)
4972  {
4973  _GLIBCXX_DEBUG_PEDASSERT(_M_ibegin() <= __i1 && __i1 <= __i2
4974  && __i2 <= _M_iend());
4975  return _M_replace_aux(__i1 - _M_ibegin(), __i2 - __i1, __n, __c);
4976  }
4977 
4978  /**
4979  * @brief Replace range of characters with range.
4980  * @param __i1 Iterator referencing start of range to replace.
4981  * @param __i2 Iterator referencing end of range to replace.
4982  * @param __k1 Iterator referencing start of range to insert.
4983  * @param __k2 Iterator referencing end of range to insert.
4984  * @return Reference to this string.
4985  * @throw std::length_error If new length exceeds @c max_size().
4986  *
4987  * Removes the characters in the range [__i1,__i2). In place,
4988  * characters in the range [__k1,__k2) are inserted. If the
4989  * length of result exceeds max_size(), length_error is thrown.
4990  * The value of the string doesn't change if an error is
4991  * thrown.
4992  */
4993  template<class _InputIterator>
4994  basic_string&
4995  replace(iterator __i1, iterator __i2,
4996  _InputIterator __k1, _InputIterator __k2)
4997  {
4998  _GLIBCXX_DEBUG_PEDASSERT(_M_ibegin() <= __i1 && __i1 <= __i2
4999  && __i2 <= _M_iend());
5000  __glibcxx_requires_valid_range(__k1, __k2);
5001  typedef typename std::__is_integer<_InputIterator>::__type _Integral;
5002  return _M_replace_dispatch(__i1, __i2, __k1, __k2, _Integral());
5003  }
5004 
5005  // Specializations for the common case of pointer and iterator:
5006  // useful to avoid the overhead of temporary buffering in _M_replace.
5007  basic_string&
5008  replace(iterator __i1, iterator __i2, _CharT* __k1, _CharT* __k2)
5009  {
5010  _GLIBCXX_DEBUG_PEDASSERT(_M_ibegin() <= __i1 && __i1 <= __i2
5011  && __i2 <= _M_iend());
5012  __glibcxx_requires_valid_range(__k1, __k2);
5013  return this->replace(__i1 - _M_ibegin(), __i2 - __i1,
5014  __k1, __k2 - __k1);
5015  }
5016 
5017  basic_string&
5018  replace(iterator __i1, iterator __i2,
5019  const _CharT* __k1, const _CharT* __k2)
5020  {
5021  _GLIBCXX_DEBUG_PEDASSERT(_M_ibegin() <= __i1 && __i1 <= __i2
5022  && __i2 <= _M_iend());
5023  __glibcxx_requires_valid_range(__k1, __k2);
5024  return this->replace(__i1 - _M_ibegin(), __i2 - __i1,
5025  __k1, __k2 - __k1);
5026  }
5027 
5028  basic_string&
5029  replace(iterator __i1, iterator __i2, iterator __k1, iterator __k2)
5030  {
5031  _GLIBCXX_DEBUG_PEDASSERT(_M_ibegin() <= __i1 && __i1 <= __i2
5032  && __i2 <= _M_iend());
5033  __glibcxx_requires_valid_range(__k1, __k2);
5034  return this->replace(__i1 - _M_ibegin(), __i2 - __i1,
5035  __k1.base(), __k2 - __k1);
5036  }
5037 
5038  basic_string&
5039  replace(iterator __i1, iterator __i2,
5040  const_iterator __k1, const_iterator __k2)
5041  {
5042  _GLIBCXX_DEBUG_PEDASSERT(_M_ibegin() <= __i1 && __i1 <= __i2
5043  && __i2 <= _M_iend());
5044  __glibcxx_requires_valid_range(__k1, __k2);
5045  return this->replace(__i1 - _M_ibegin(), __i2 - __i1,
5046  __k1.base(), __k2 - __k1);
5047  }
5048 
5049 #if __cplusplus >= 201103L
5050  /**
5051  * @brief Replace range of characters with initializer_list.
5052  * @param __i1 Iterator referencing start of range to replace.
5053  * @param __i2 Iterator referencing end of range to replace.
5054  * @param __l The initializer_list of characters to insert.
5055  * @return Reference to this string.
5056  * @throw std::length_error If new length exceeds @c max_size().
5057  *
5058  * Removes the characters in the range [__i1,__i2). In place,
5059  * characters in the range [__k1,__k2) are inserted. If the
5060  * length of result exceeds max_size(), length_error is thrown.
5061  * The value of the string doesn't change if an error is
5062  * thrown.
5063  */
5064  basic_string& replace(iterator __i1, iterator __i2,
5066  { return this->replace(__i1, __i2, __l.begin(), __l.end()); }
5067 #endif // C++11
5068 
5069 #if __cplusplus >= 201703L
5070  /**
5071  * @brief Replace range of characters with string_view.
5072  * @param __pos The position to replace at.
5073  * @param __n The number of characters to replace.
5074  * @param __svt The object convertible to string_view to insert.
5075  * @return Reference to this string.
5076  */
5077  template<typename _Tp>
5078  _If_sv<_Tp, basic_string&>
5079  replace(size_type __pos, size_type __n, const _Tp& __svt)
5080  {
5081  __sv_type __sv = __svt;
5082  return this->replace(__pos, __n, __sv.data(), __sv.size());
5083  }
5084 
5085  /**
5086  * @brief Replace range of characters with string_view.
5087  * @param __pos1 The position to replace at.
5088  * @param __n1 The number of characters to replace.
5089  * @param __svt The object convertible to string_view to insert from.
5090  * @param __pos2 The position in the string_view to insert from.
5091  * @param __n2 The number of characters to insert.
5092  * @return Reference to this string.
5093  */
5094  template<typename _Tp>
5095  _If_sv<_Tp, basic_string&>
5096  replace(size_type __pos1, size_type __n1, const _Tp& __svt,
5097  size_type __pos2, size_type __n2 = npos)
5098  {
5099  __sv_type __sv = __svt;
5100  return this->replace(__pos1, __n1,
5101  __sv.data()
5102  + std::__sv_check(__sv.size(), __pos2, "basic_string::replace"),
5103  std::__sv_limit(__sv.size(), __pos2, __n2));
5104  }
5105 
5106  /**
5107  * @brief Replace range of characters with string_view.
5108  * @param __i1 An iterator referencing the start position
5109  to replace at.
5110  * @param __i2 An iterator referencing the end position
5111  for the replace.
5112  * @param __svt The object convertible to string_view to insert from.
5113  * @return Reference to this string.
5114  */
5115  template<typename _Tp>
5116  _If_sv<_Tp, basic_string&>
5117  replace(const_iterator __i1, const_iterator __i2, const _Tp& __svt)
5118  {
5119  __sv_type __sv = __svt;
5120  return this->replace(__i1 - begin(), __i2 - __i1, __sv);
5121  }
5122 #endif // C++17
5123 
5124  private:
5125  template<class _Integer>
5126  basic_string&
5127  _M_replace_dispatch(iterator __i1, iterator __i2, _Integer __n,
5128  _Integer __val, __true_type)
5129  { return _M_replace_aux(__i1 - _M_ibegin(), __i2 - __i1, __n, __val); }
5130 
5131  template<class _InputIterator>
5132  basic_string&
5133  _M_replace_dispatch(iterator __i1, iterator __i2, _InputIterator __k1,
5134  _InputIterator __k2, __false_type);
5135 
5136  basic_string&
5137  _M_replace_aux(size_type __pos1, size_type __n1, size_type __n2,
5138  _CharT __c);
5139 
5140  basic_string&
5141  _M_replace_safe(size_type __pos1, size_type __n1, const _CharT* __s,
5142  size_type __n2);
5143 
5144  // _S_construct_aux is used to implement the 21.3.1 para 15 which
5145  // requires special behaviour if _InIter is an integral type
5146  template<class _InIterator>
5147  static _CharT*
5148  _S_construct_aux(_InIterator __beg, _InIterator __end,
5149  const _Alloc& __a, __false_type)
5150  {
5151  typedef typename iterator_traits<_InIterator>::iterator_category _Tag;
5152  return _S_construct(__beg, __end, __a, _Tag());
5153  }
5154 
5155  // _GLIBCXX_RESOLVE_LIB_DEFECTS
5156  // 438. Ambiguity in the "do the right thing" clause
5157  template<class _Integer>
5158  static _CharT*
5159  _S_construct_aux(_Integer __beg, _Integer __end,
5160  const _Alloc& __a, __true_type)
5161  { return _S_construct_aux_2(static_cast<size_type>(__beg),
5162  __end, __a); }
5163 
5164  static _CharT*
5165  _S_construct_aux_2(size_type __req, _CharT __c, const _Alloc& __a)
5166  { return _S_construct(__req, __c, __a); }
5167 
5168  template<class _InIterator>
5169  static _CharT*
5170  _S_construct(_InIterator __beg, _InIterator __end, const _Alloc& __a)
5171  {
5172  typedef typename std::__is_integer<_InIterator>::__type _Integral;
5173  return _S_construct_aux(__beg, __end, __a, _Integral());
5174  }
5175 
5176  // For Input Iterators, used in istreambuf_iterators, etc.
5177  template<class _InIterator>
5178  static _CharT*
5179  _S_construct(_InIterator __beg, _InIterator __end, const _Alloc& __a,
5180  input_iterator_tag);
5181 
5182  // For forward_iterators up to random_access_iterators, used for
5183  // string::iterator, _CharT*, etc.
5184  template<class _FwdIterator>
5185  static _CharT*
5186  _S_construct(_FwdIterator __beg, _FwdIterator __end, const _Alloc& __a,
5187  forward_iterator_tag);
5188 
5189  static _CharT*
5190  _S_construct(size_type __req, _CharT __c, const _Alloc& __a);
5191 
5192  public:
5193 
5194  /**
5195  * @brief Copy substring into C string.
5196  * @param __s C string to copy value into.
5197  * @param __n Number of characters to copy.
5198  * @param __pos Index of first character to copy.
5199  * @return Number of characters actually copied
5200  * @throw std::out_of_range If __pos > size().
5201  *
5202  * Copies up to @a __n characters starting at @a __pos into the
5203  * C string @a __s. If @a __pos is %greater than size(),
5204  * out_of_range is thrown.
5205  */
5206  size_type
5207  copy(_CharT* __s, size_type __n, size_type __pos = 0) const;
5208 
5209  /**
5210  * @brief Swap contents with another string.
5211  * @param __s String to swap with.
5212  *
5213  * Exchanges the contents of this string with that of @a __s in constant
5214  * time.
5215  */
5216  void
5217  swap(basic_string& __s)
5218  _GLIBCXX_NOEXCEPT_IF(allocator_traits<_Alloc>::is_always_equal::value);
5219 
5220  // String operations:
5221  /**
5222  * @brief Return const pointer to null-terminated contents.
5223  *
5224  * This is a handle to internal data. Do not modify or dire things may
5225  * happen.
5226  */
5227  const _CharT*
5228  c_str() const _GLIBCXX_NOEXCEPT
5229  { return _M_data(); }
5230 
5231  /**
5232  * @brief Return const pointer to contents.
5233  *
5234  * This is a pointer to internal data. It is undefined to modify
5235  * the contents through the returned pointer. To get a pointer that
5236  * allows modifying the contents use @c &str[0] instead,
5237  * (or in C++17 the non-const @c str.data() overload).
5238  */
5239  const _CharT*
5240  data() const _GLIBCXX_NOEXCEPT
5241  { return _M_data(); }
5242 
5243 #if __cplusplus >= 201703L
5244  /**
5245  * @brief Return non-const pointer to contents.
5246  *
5247  * This is a pointer to the character sequence held by the string.
5248  * Modifying the characters in the sequence is allowed.
5249  */
5250  _CharT*
5251  data() noexcept
5252  {
5253  _M_leak();
5254  return _M_data();
5255  }
5256 #endif
5257 
5258  /**
5259  * @brief Return copy of allocator used to construct this string.
5260  */
5261  allocator_type
5262  get_allocator() const _GLIBCXX_NOEXCEPT
5263  { return _M_dataplus; }
5264 
5265  /**
5266  * @brief Find position of a C substring.
5267  * @param __s C string to locate.
5268  * @param __pos Index of character to search from.
5269  * @param __n Number of characters from @a s to search for.
5270  * @return Index of start of first occurrence.
5271  *
5272  * Starting from @a __pos, searches forward for the first @a
5273  * __n characters in @a __s within this string. If found,
5274  * returns the index where it begins. If not found, returns
5275  * npos.
5276  */
5277  size_type
5278  find(const _CharT* __s, size_type __pos, size_type __n) const
5279  _GLIBCXX_NOEXCEPT;
5280 
5281  /**
5282  * @brief Find position of a string.
5283  * @param __str String to locate.
5284  * @param __pos Index of character to search from (default 0).
5285  * @return Index of start of first occurrence.
5286  *
5287  * Starting from @a __pos, searches forward for value of @a __str within
5288  * this string. If found, returns the index where it begins. If not
5289  * found, returns npos.
5290  */
5291  size_type
5292  find(const basic_string& __str, size_type __pos = 0) const
5293  _GLIBCXX_NOEXCEPT
5294  { return this->find(__str.data(), __pos, __str.size()); }
5295 
5296  /**
5297  * @brief Find position of a C string.
5298  * @param __s C string to locate.
5299  * @param __pos Index of character to search from (default 0).
5300  * @return Index of start of first occurrence.
5301  *
5302  * Starting from @a __pos, searches forward for the value of @a
5303  * __s within this string. If found, returns the index where
5304  * it begins. If not found, returns npos.
5305  */
5306  size_type
5307  find(const _CharT* __s, size_type __pos = 0) const _GLIBCXX_NOEXCEPT
5308  {
5309  __glibcxx_requires_string(__s);
5310  return this->find(__s, __pos, traits_type::length(__s));
5311  }
5312 
5313  /**
5314  * @brief Find position of a character.
5315  * @param __c Character to locate.
5316  * @param __pos Index of character to search from (default 0).
5317  * @return Index of first occurrence.
5318  *
5319  * Starting from @a __pos, searches forward for @a __c within
5320  * this string. If found, returns the index where it was
5321  * found. If not found, returns npos.
5322  */
5323  size_type
5324  find(_CharT __c, size_type __pos = 0) const _GLIBCXX_NOEXCEPT;
5325 
5326 #if __cplusplus >= 201703L
5327  /**
5328  * @brief Find position of a string_view.
5329  * @param __svt The object convertible to string_view to locate.
5330  * @param __pos Index of character to search from (default 0).
5331  * @return Index of start of first occurrence.
5332  */
5333  template<typename _Tp>
5334  _If_sv<_Tp, size_type>
5335  find(const _Tp& __svt, size_type __pos = 0) const
5336  noexcept(is_same<_Tp, __sv_type>::value)
5337  {
5338  __sv_type __sv = __svt;
5339  return this->find(__sv.data(), __pos, __sv.size());
5340  }
5341 #endif // C++17
5342 
5343  /**
5344  * @brief Find last position of a string.
5345  * @param __str String to locate.
5346  * @param __pos Index of character to search back from (default end).
5347  * @return Index of start of last occurrence.
5348  *
5349  * Starting from @a __pos, searches backward for value of @a
5350  * __str within this string. If found, returns the index where
5351  * it begins. If not found, returns npos.
5352  */
5353  size_type
5354  rfind(const basic_string& __str, size_type __pos = npos) const
5355  _GLIBCXX_NOEXCEPT
5356  { return this->rfind(__str.data(), __pos, __str.size()); }
5357 
5358  /**
5359  * @brief Find last position of a C substring.
5360  * @param __s C string to locate.
5361  * @param __pos Index of character to search back from.
5362  * @param __n Number of characters from s to search for.
5363  * @return Index of start of last occurrence.
5364  *
5365  * Starting from @a __pos, searches backward for the first @a
5366  * __n characters in @a __s within this string. If found,
5367  * returns the index where it begins. If not found, returns
5368  * npos.
5369  */
5370  size_type
5371  rfind(const _CharT* __s, size_type __pos, size_type __n) const
5372  _GLIBCXX_NOEXCEPT;
5373 
5374  /**
5375  * @brief Find last position of a C string.
5376  * @param __s C string to locate.
5377  * @param __pos Index of character to start search at (default end).
5378  * @return Index of start of last occurrence.
5379  *
5380  * Starting from @a __pos, searches backward for the value of
5381  * @a __s within this string. If found, returns the index
5382  * where it begins. If not found, returns npos.
5383  */
5384  size_type
5385  rfind(const _CharT* __s, size_type __pos = npos) const _GLIBCXX_NOEXCEPT
5386  {
5387  __glibcxx_requires_string(__s);
5388  return this->rfind(__s, __pos, traits_type::length(__s));
5389  }
5390 
5391  /**
5392  * @brief Find last position of a character.
5393  * @param __c Character to locate.
5394  * @param __pos Index of character to search back from (default end).
5395  * @return Index of last occurrence.
5396  *
5397  * Starting from @a __pos, searches backward for @a __c within
5398  * this string. If found, returns the index where it was
5399  * found. If not found, returns npos.
5400  */
5401  size_type
5402  rfind(_CharT __c, size_type __pos = npos) const _GLIBCXX_NOEXCEPT;
5403 
5404 #if __cplusplus >= 201703L
5405  /**
5406  * @brief Find last position of a string_view.
5407  * @param __svt The object convertible to string_view to locate.
5408  * @param __pos Index of character to search back from (default end).
5409  * @return Index of start of last occurrence.
5410  */
5411  template<typename _Tp>
5412  _If_sv<_Tp, size_type>
5413  rfind(const _Tp& __svt, size_type __pos = npos) const
5415  {
5416  __sv_type __sv = __svt;
5417  return this->rfind(__sv.data(), __pos, __sv.size());
5418  }
5419 #endif // C++17
5420 
5421  /**
5422  * @brief Find position of a character of string.
5423  * @param __str String containing characters to locate.
5424  * @param __pos Index of character to search from (default 0).
5425  * @return Index of first occurrence.
5426  *
5427  * Starting from @a __pos, searches forward for one of the
5428  * characters of @a __str within this string. If found,
5429  * returns the index where it was found. If not found, returns
5430  * npos.
5431  */
5432  size_type
5433  find_first_of(const basic_string& __str, size_type __pos = 0) const
5434  _GLIBCXX_NOEXCEPT
5435  { return this->find_first_of(__str.data(), __pos, __str.size()); }
5436 
5437  /**
5438  * @brief Find position of a character of C substring.
5439  * @param __s String containing characters to locate.
5440  * @param __pos Index of character to search from.
5441  * @param __n Number of characters from s to search for.
5442  * @return Index of first occurrence.
5443  *
5444  * Starting from @a __pos, searches forward for one of the
5445  * first @a __n characters of @a __s within this string. If
5446  * found, returns the index where it was found. If not found,
5447  * returns npos.
5448  */
5449  size_type
5450  find_first_of(const _CharT* __s, size_type __pos, size_type __n) const
5451  _GLIBCXX_NOEXCEPT;
5452 
5453  /**
5454  * @brief Find position of a character of C string.
5455  * @param __s String containing characters to locate.
5456  * @param __pos Index of character to search from (default 0).
5457  * @return Index of first occurrence.
5458  *
5459  * Starting from @a __pos, searches forward for one of the
5460  * characters of @a __s within this string. If found, returns
5461  * the index where it was found. If not found, returns npos.
5462  */
5463  size_type
5464  find_first_of(const _CharT* __s, size_type __pos = 0) const
5465  _GLIBCXX_NOEXCEPT
5466  {
5467  __glibcxx_requires_string(__s);
5468  return this->find_first_of(__s, __pos, traits_type::length(__s));
5469  }
5470 
5471  /**
5472  * @brief Find position of a character.
5473  * @param __c Character to locate.
5474  * @param __pos Index of character to search from (default 0).
5475  * @return Index of first occurrence.
5476  *
5477  * Starting from @a __pos, searches forward for the character
5478  * @a __c within this string. If found, returns the index
5479  * where it was found. If not found, returns npos.
5480  *
5481  * Note: equivalent to find(__c, __pos).
5482  */
5483  size_type
5484  find_first_of(_CharT __c, size_type __pos = 0) const _GLIBCXX_NOEXCEPT
5485  { return this->find(__c, __pos); }
5486 
5487 #if __cplusplus >= 201703L
5488  /**
5489  * @brief Find position of a character of a string_view.
5490  * @param __svt An object convertible to string_view containing
5491  * characters to locate.
5492  * @param __pos Index of character to search from (default 0).
5493  * @return Index of first occurrence.
5494  */
5495  template<typename _Tp>
5496  _If_sv<_Tp, size_type>
5497  find_first_of(const _Tp& __svt, size_type __pos = 0) const
5498  noexcept(is_same<_Tp, __sv_type>::value)
5499  {
5500  __sv_type __sv = __svt;
5501  return this->find_first_of(__sv.data(), __pos, __sv.size());
5502  }
5503 #endif // C++17
5504 
5505  /**
5506  * @brief Find last position of a character of string.
5507  * @param __str String containing characters to locate.
5508  * @param __pos Index of character to search back from (default end).
5509  * @return Index of last occurrence.
5510  *
5511  * Starting from @a __pos, searches backward for one of the
5512  * characters of @a __str within this string. If found,
5513  * returns the index where it was found. If not found, returns
5514  * npos.
5515  */
5516  size_type
5517  find_last_of(const basic_string& __str, size_type __pos = npos) const
5518  _GLIBCXX_NOEXCEPT
5519  { return this->find_last_of(__str.data(), __pos, __str.size()); }
5520 
5521  /**
5522  * @brief Find last position of a character of C substring.
5523  * @param __s C string containing characters to locate.
5524  * @param __pos Index of character to search back from.
5525  * @param __n Number of characters from s to search for.
5526  * @return Index of last occurrence.
5527  *
5528  * Starting from @a __pos, searches backward for one of the
5529  * first @a __n characters of @a __s within this string. If
5530  * found, returns the index where it was found. If not found,
5531  * returns npos.
5532  */
5533  size_type
5534  find_last_of(const _CharT* __s, size_type __pos, size_type __n) const
5535  _GLIBCXX_NOEXCEPT;
5536 
5537  /**
5538  * @brief Find last position of a character of C string.
5539  * @param __s C string containing characters to locate.
5540  * @param __pos Index of character to search back from (default end).
5541  * @return Index of last occurrence.
5542  *
5543  * Starting from @a __pos, searches backward for one of the
5544  * characters of @a __s within this string. If found, returns
5545  * the index where it was found. If not found, returns npos.
5546  */
5547  size_type
5548  find_last_of(const _CharT* __s, size_type __pos = npos) const
5549  _GLIBCXX_NOEXCEPT
5550  {
5551  __glibcxx_requires_string(__s);
5552  return this->find_last_of(__s, __pos, traits_type::length(__s));
5553  }
5554 
5555  /**
5556  * @brief Find last position of a character.
5557  * @param __c Character to locate.
5558  * @param __pos Index of character to search back from (default end).
5559  * @return Index of last occurrence.
5560  *
5561  * Starting from @a __pos, searches backward for @a __c within
5562  * this string. If found, returns the index where it was
5563  * found. If not found, returns npos.
5564  *
5565  * Note: equivalent to rfind(__c, __pos).
5566  */
5567  size_type
5568  find_last_of(_CharT __c, size_type __pos = npos) const _GLIBCXX_NOEXCEPT
5569  { return this->rfind(__c, __pos); }
5570 
5571 #if __cplusplus >= 201703L
5572  /**
5573  * @brief Find last position of a character of string.
5574  * @param __svt An object convertible to string_view containing
5575  * characters to locate.
5576  * @param __pos Index of character to search back from (default end).
5577  * @return Index of last occurrence.
5578  */
5579  template<typename _Tp>
5580  _If_sv<_Tp, size_type>
5581  find_last_of(const _Tp& __svt, size_type __pos = npos) const
5583  {
5584  __sv_type __sv = __svt;
5585  return this->find_last_of(__sv.data(), __pos, __sv.size());
5586  }
5587 #endif // C++17
5588 
5589  /**
5590  * @brief Find position of a character not in string.
5591  * @param __str String containing characters to avoid.
5592  * @param __pos Index of character to search from (default 0).
5593  * @return Index of first occurrence.
5594  *
5595  * Starting from @a __pos, searches forward for a character not contained
5596  * in @a __str within this string. If found, returns the index where it
5597  * was found. If not found, returns npos.
5598  */
5599  size_type
5600  find_first_not_of(const basic_string& __str, size_type __pos = 0) const
5601  _GLIBCXX_NOEXCEPT
5602  { return this->find_first_not_of(__str.data(), __pos, __str.size()); }
5603 
5604  /**
5605  * @brief Find position of a character not in C substring.
5606  * @param __s C string containing characters to avoid.
5607  * @param __pos Index of character to search from.
5608  * @param __n Number of characters from __s to consider.
5609  * @return Index of first occurrence.
5610  *
5611  * Starting from @a __pos, searches forward for a character not
5612  * contained in the first @a __n characters of @a __s within
5613  * this string. If found, returns the index where it was
5614  * found. If not found, returns npos.
5615  */
5616  size_type
5617  find_first_not_of(const _CharT* __s, size_type __pos,
5618  size_type __n) const _GLIBCXX_NOEXCEPT;
5619 
5620  /**
5621  * @brief Find position of a character not in C string.
5622  * @param __s C string containing characters to avoid.
5623  * @param __pos Index of character to search from (default 0).
5624  * @return Index of first occurrence.
5625  *
5626  * Starting from @a __pos, searches forward for a character not
5627  * contained in @a __s within this string. If found, returns
5628  * the index where it was found. If not found, returns npos.
5629  */
5630  size_type
5631  find_first_not_of(const _CharT* __s, size_type __pos = 0) const
5632  _GLIBCXX_NOEXCEPT
5633  {
5634  __glibcxx_requires_string(__s);
5635  return this->find_first_not_of(__s, __pos, traits_type::length(__s));
5636  }
5637 
5638  /**
5639  * @brief Find position of a different character.
5640  * @param __c Character to avoid.
5641  * @param __pos Index of character to search from (default 0).
5642  * @return Index of first occurrence.
5643  *
5644  * Starting from @a __pos, searches forward for a character
5645  * other than @a __c within this string. If found, returns the
5646  * index where it was found. If not found, returns npos.
5647  */
5648  size_type
5649  find_first_not_of(_CharT __c, size_type __pos = 0) const
5650  _GLIBCXX_NOEXCEPT;
5651 
5652 #if __cplusplus >= 201703L
5653  /**
5654  * @brief Find position of a character not in a string_view.
5655  * @param __svt An object convertible to string_view containing
5656  * characters to avoid.
5657  * @param __pos Index of character to search from (default 0).
5658  * @return Index of first occurrence.
5659  */
5660  template<typename _Tp>
5661  _If_sv<_Tp, size_type>
5662  find_first_not_of(const _Tp& __svt, size_type __pos = 0) const
5663  noexcept(is_same<_Tp, __sv_type>::value)
5664  {
5665  __sv_type __sv = __svt;
5666  return this->find_first_not_of(__sv.data(), __pos, __sv.size());
5667  }
5668 #endif // C++17
5669 
5670  /**
5671  * @brief Find last position of a character not in string.
5672  * @param __str String containing characters to avoid.
5673  * @param __pos Index of character to search back from (default end).
5674  * @return Index of last occurrence.
5675  *
5676  * Starting from @a __pos, searches backward for a character
5677  * not contained in @a __str within this string. If found,
5678  * returns the index where it was found. If not found, returns
5679  * npos.
5680  */
5681  size_type
5682  find_last_not_of(const basic_string& __str, size_type __pos = npos) const
5683  _GLIBCXX_NOEXCEPT
5684  { return this->find_last_not_of(__str.data(), __pos, __str.size()); }
5685 
5686  /**
5687  * @brief Find last position of a character not in C substring.
5688  * @param __s C string containing characters to avoid.
5689  * @param __pos Index of character to search back from.
5690  * @param __n Number of characters from s to consider.
5691  * @return Index of last occurrence.
5692  *
5693  * Starting from @a __pos, searches backward for a character not
5694  * contained in the first @a __n characters of @a __s within this string.
5695  * If found, returns the index where it was found. If not found,
5696  * returns npos.
5697  */
5698  size_type
5699  find_last_not_of(const _CharT* __s, size_type __pos,
5700  size_type __n) const _GLIBCXX_NOEXCEPT;
5701  /**
5702  * @brief Find last position of a character not in C string.
5703  * @param __s C string containing characters to avoid.
5704  * @param __pos Index of character to search back from (default end).
5705  * @return Index of last occurrence.
5706  *
5707  * Starting from @a __pos, searches backward for a character
5708  * not contained in @a __s within this string. If found,
5709  * returns the index where it was found. If not found, returns
5710  * npos.
5711  */
5712  size_type
5713  find_last_not_of(const _CharT* __s, size_type __pos = npos) const
5714  _GLIBCXX_NOEXCEPT
5715  {
5716  __glibcxx_requires_string(__s);
5717  return this->find_last_not_of(__s, __pos, traits_type::length(__s));
5718  }
5719 
5720  /**
5721  * @brief Find last position of a different character.
5722  * @param __c Character to avoid.
5723  * @param __pos Index of character to search back from (default end).
5724  * @return Index of last occurrence.
5725  *
5726  * Starting from @a __pos, searches backward for a character other than
5727  * @a __c within this string. If found, returns the index where it was
5728  * found. If not found, returns npos.
5729  */
5730  size_type
5731  find_last_not_of(_CharT __c, size_type __pos = npos) const
5732  _GLIBCXX_NOEXCEPT;
5733 
5734 #if __cplusplus >= 201703L
5735  /**
5736  * @brief Find last position of a character not in a string_view.
5737  * @param __svt An object convertible to string_view containing
5738  * characters to avoid.
5739  * @param __pos Index of character to search back from (default end).
5740  * @return Index of last occurrence.
5741  */
5742  template<typename _Tp>
5743  _If_sv<_Tp, size_type>
5744  find_last_not_of(const _Tp& __svt, size_type __pos = npos) const
5746  {
5747  __sv_type __sv = __svt;
5748  return this->find_last_not_of(__sv.data(), __pos, __sv.size());
5749  }
5750 #endif // C++17
5751 
5752  /**
5753  * @brief Get a substring.
5754  * @param __pos Index of first character (default 0).
5755  * @param __n Number of characters in substring (default remainder).
5756  * @return The new string.
5757  * @throw std::out_of_range If __pos > size().
5758  *
5759  * Construct and return a new string using the @a __n
5760  * characters starting at @a __pos. If the string is too
5761  * short, use the remainder of the characters. If @a __pos is
5762  * beyond the end of the string, out_of_range is thrown.
5763  */
5764  basic_string
5765  substr(size_type __pos = 0, size_type __n = npos) const
5766  { return basic_string(*this,
5767  _M_check(__pos, "basic_string::substr"), __n); }
5768 
5769  /**
5770  * @brief Compare to a string.
5771  * @param __str String to compare against.
5772  * @return Integer < 0, 0, or > 0.
5773  *
5774  * Returns an integer < 0 if this string is ordered before @a
5775  * __str, 0 if their values are equivalent, or > 0 if this
5776  * string is ordered after @a __str. Determines the effective
5777  * length rlen of the strings to compare as the smallest of
5778  * size() and str.size(). The function then compares the two
5779  * strings by calling traits::compare(data(), str.data(),rlen).
5780  * If the result of the comparison is nonzero returns it,
5781  * otherwise the shorter one is ordered first.
5782  */
5783  int
5784  compare(const basic_string& __str) const
5785  {
5786  const size_type __size = this->size();
5787  const size_type __osize = __str.size();
5788  const size_type __len = std::min(__size, __osize);
5789 
5790  int __r = traits_type::compare(_M_data(), __str.data(), __len);
5791  if (!__r)
5792  __r = _S_compare(__size, __osize);
5793  return __r;
5794  }
5795 
5796 #if __cplusplus >= 201703L
5797  /**
5798  * @brief Compare to a string_view.
5799  * @param __svt An object convertible to string_view to compare against.
5800  * @return Integer < 0, 0, or > 0.
5801  */
5802  template<typename _Tp>
5803  _If_sv<_Tp, int>
5804  compare(const _Tp& __svt) const
5806  {
5807  __sv_type __sv = __svt;
5808  const size_type __size = this->size();
5809  const size_type __osize = __sv.size();
5810  const size_type __len = std::min(__size, __osize);
5811 
5812  int __r = traits_type::compare(_M_data(), __sv.data(), __len);
5813  if (!__r)
5814  __r = _S_compare(__size, __osize);
5815  return __r;
5816  }
5817 
5818  /**
5819  * @brief Compare to a string_view.
5820  * @param __pos A position in the string to start comparing from.
5821  * @param __n The number of characters to compare.
5822  * @param __svt An object convertible to string_view to compare
5823  * against.
5824  * @return Integer < 0, 0, or > 0.
5825  */
5826  template<typename _Tp>
5827  _If_sv<_Tp, int>
5828  compare(size_type __pos, size_type __n, const _Tp& __svt) const
5830  {
5831  __sv_type __sv = __svt;
5832  return __sv_type(*this).substr(__pos, __n).compare(__sv);
5833  }
5834 
5835  /**
5836  * @brief Compare to a string_view.
5837  * @param __pos1 A position in the string to start comparing from.
5838  * @param __n1 The number of characters to compare.
5839  * @param __svt An object convertible to string_view to compare
5840  * against.
5841  * @param __pos2 A position in the string_view to start comparing from.
5842  * @param __n2 The number of characters to compare.
5843  * @return Integer < 0, 0, or > 0.
5844  */
5845  template<typename _Tp>
5846  _If_sv<_Tp, int>
5847  compare(size_type __pos1, size_type __n1, const _Tp& __svt,
5848  size_type __pos2, size_type __n2 = npos) const
5850  {
5851  __sv_type __sv = __svt;
5852  return __sv_type(*this)
5853  .substr(__pos1, __n1).compare(__sv.substr(__pos2, __n2));
5854  }
5855 #endif // C++17
5856 
5857  /**
5858  * @brief Compare substring to a string.
5859  * @param __pos Index of first character of substring.
5860  * @param __n Number of characters in substring.
5861  * @param __str String to compare against.
5862  * @return Integer < 0, 0, or > 0.
5863  *
5864  * Form the substring of this string from the @a __n characters
5865  * starting at @a __pos. Returns an integer < 0 if the
5866  * substring is ordered before @a __str, 0 if their values are
5867  * equivalent, or > 0 if the substring is ordered after @a
5868  * __str. Determines the effective length rlen of the strings
5869  * to compare as the smallest of the length of the substring
5870  * and @a __str.size(). The function then compares the two
5871  * strings by calling
5872  * traits::compare(substring.data(),str.data(),rlen). If the
5873  * result of the comparison is nonzero returns it, otherwise
5874  * the shorter one is ordered first.
5875  */
5876  int
5877  compare(size_type __pos, size_type __n, const basic_string& __str) const;
5878 
5879  /**
5880  * @brief Compare substring to a substring.
5881  * @param __pos1 Index of first character of substring.
5882  * @param __n1 Number of characters in substring.
5883  * @param __str String to compare against.
5884  * @param __pos2 Index of first character of substring of str.
5885  * @param __n2 Number of characters in substring of str.
5886  * @return Integer < 0, 0, or > 0.
5887  *
5888  * Form the substring of this string from the @a __n1
5889  * characters starting at @a __pos1. Form the substring of @a
5890  * __str from the @a __n2 characters starting at @a __pos2.
5891  * Returns an integer < 0 if this substring is ordered before
5892  * the substring of @a __str, 0 if their values are equivalent,
5893  * or > 0 if this substring is ordered after the substring of
5894  * @a __str. Determines the effective length rlen of the
5895  * strings to compare as the smallest of the lengths of the
5896  * substrings. The function then compares the two strings by
5897  * calling
5898  * traits::compare(substring.data(),str.substr(pos2,n2).data(),rlen).
5899  * If the result of the comparison is nonzero returns it,
5900  * otherwise the shorter one is ordered first.
5901  */
5902  int
5903  compare(size_type __pos1, size_type __n1, const basic_string& __str,
5904  size_type __pos2, size_type __n2 = npos) const;
5905 
5906  /**
5907  * @brief Compare to a C string.
5908  * @param __s C string to compare against.
5909  * @return Integer < 0, 0, or > 0.
5910  *
5911  * Returns an integer < 0 if this string is ordered before @a __s, 0 if
5912  * their values are equivalent, or > 0 if this string is ordered after
5913  * @a __s. Determines the effective length rlen of the strings to
5914  * compare as the smallest of size() and the length of a string
5915  * constructed from @a __s. The function then compares the two strings
5916  * by calling traits::compare(data(),s,rlen). If the result of the
5917  * comparison is nonzero returns it, otherwise the shorter one is
5918  * ordered first.
5919  */
5920  int
5921  compare(const _CharT* __s) const _GLIBCXX_NOEXCEPT;
5922 
5923  // _GLIBCXX_RESOLVE_LIB_DEFECTS
5924  // 5 String::compare specification questionable
5925  /**
5926  * @brief Compare substring to a C string.
5927  * @param __pos Index of first character of substring.
5928  * @param __n1 Number of characters in substring.
5929  * @param __s C string to compare against.
5930  * @return Integer < 0, 0, or > 0.
5931  *
5932  * Form the substring of this string from the @a __n1
5933  * characters starting at @a pos. Returns an integer < 0 if
5934  * the substring is ordered before @a __s, 0 if their values
5935  * are equivalent, or > 0 if the substring is ordered after @a
5936  * __s. Determines the effective length rlen of the strings to
5937  * compare as the smallest of the length of the substring and
5938  * the length of a string constructed from @a __s. The
5939  * function then compares the two string by calling
5940  * traits::compare(substring.data(),__s,rlen). If the result of
5941  * the comparison is nonzero returns it, otherwise the shorter
5942  * one is ordered first.
5943  */
5944  int
5945  compare(size_type __pos, size_type __n1, const _CharT* __s) const;
5946 
5947  /**
5948  * @brief Compare substring against a character %array.
5949  * @param __pos Index of first character of substring.
5950  * @param __n1 Number of characters in substring.
5951  * @param __s character %array to compare against.
5952  * @param __n2 Number of characters of s.
5953  * @return Integer < 0, 0, or > 0.
5954  *
5955  * Form the substring of this string from the @a __n1
5956  * characters starting at @a __pos. Form a string from the
5957  * first @a __n2 characters of @a __s. Returns an integer < 0
5958  * if this substring is ordered before the string from @a __s,
5959  * 0 if their values are equivalent, or > 0 if this substring
5960  * is ordered after the string from @a __s. Determines the
5961  * effective length rlen of the strings to compare as the
5962  * smallest of the length of the substring and @a __n2. The
5963  * function then compares the two strings by calling
5964  * traits::compare(substring.data(),s,rlen). If the result of
5965  * the comparison is nonzero returns it, otherwise the shorter
5966  * one is ordered first.
5967  *
5968  * NB: s must have at least n2 characters, &apos;\\0&apos; has
5969  * no special meaning.
5970  */
5971  int
5972  compare(size_type __pos, size_type __n1, const _CharT* __s,
5973  size_type __n2) const;
5974 
5975 #if __cplusplus > 201703L
5976  bool
5977  starts_with(basic_string_view<_CharT, _Traits> __x) const noexcept
5978  { return __sv_type(this->data(), this->size()).starts_with(__x); }
5979 
5980  bool
5981  starts_with(_CharT __x) const noexcept
5982  { return __sv_type(this->data(), this->size()).starts_with(__x); }
5983 
5984  bool
5985  starts_with(const _CharT* __x) const noexcept
5986  { return __sv_type(this->data(), this->size()).starts_with(__x); }
5987 
5988  bool
5989  ends_with(basic_string_view<_CharT, _Traits> __x) const noexcept
5990  { return __sv_type(this->data(), this->size()).ends_with(__x); }
5991 
5992  bool
5993  ends_with(_CharT __x) const noexcept
5994  { return __sv_type(this->data(), this->size()).ends_with(__x); }
5995 
5996  bool
5997  ends_with(const _CharT* __x) const noexcept
5998  { return __sv_type(this->data(), this->size()).ends_with(__x); }
5999 #endif // C++20
6000 
6001 # ifdef _GLIBCXX_TM_TS_INTERNAL
6002  friend void
6003  ::_txnal_cow_string_C1_for_exceptions(void* that, const char* s,
6004  void* exc);
6005  friend const char*
6006  ::_txnal_cow_string_c_str(const void *that);
6007  friend void
6008  ::_txnal_cow_string_D1(void *that);
6009  friend void
6010  ::_txnal_cow_string_D1_commit(void *that);
6011 # endif
6012  };
6013 #endif // !_GLIBCXX_USE_CXX11_ABI
6014 
6015 #if __cpp_deduction_guides >= 201606
6016 _GLIBCXX_BEGIN_NAMESPACE_CXX11
6017  template<typename _InputIterator, typename _CharT
6018  = typename iterator_traits<_InputIterator>::value_type,
6019  typename _Allocator = allocator<_CharT>,
6020  typename = _RequireInputIter<_InputIterator>,
6021  typename = _RequireAllocator<_Allocator>>
6022  basic_string(_InputIterator, _InputIterator, _Allocator = _Allocator())
6023  -> basic_string<_CharT, char_traits<_CharT>, _Allocator>;
6024 
6025  // _GLIBCXX_RESOLVE_LIB_DEFECTS
6026  // 3075. basic_string needs deduction guides from basic_string_view
6027  template<typename _CharT, typename _Traits,
6028  typename _Allocator = allocator<_CharT>,
6029  typename = _RequireAllocator<_Allocator>>
6030  basic_string(basic_string_view<_CharT, _Traits>, const _Allocator& = _Allocator())
6031  -> basic_string<_CharT, _Traits, _Allocator>;
6032 
6033  template<typename _CharT, typename _Traits,
6034  typename _Allocator = allocator<_CharT>,
6035  typename = _RequireAllocator<_Allocator>>
6036  basic_string(basic_string_view<_CharT, _Traits>,
6037  typename basic_string<_CharT, _Traits, _Allocator>::size_type,
6038  typename basic_string<_CharT, _Traits, _Allocator>::size_type,
6039  const _Allocator& = _Allocator())
6040  -> basic_string<_CharT, _Traits, _Allocator>;
6041 _GLIBCXX_END_NAMESPACE_CXX11
6042 #endif
6043 
6044  // operator+
6045  /**
6046  * @brief Concatenate two strings.
6047  * @param __lhs First string.
6048  * @param __rhs Last string.
6049  * @return New string with value of @a __lhs followed by @a __rhs.
6050  */
6051  template<typename _CharT, typename _Traits, typename _Alloc>
6052  basic_string<_CharT, _Traits, _Alloc>
6055  {
6057  __str.append(__rhs);
6058  return __str;
6059  }
6060 
6061  /**
6062  * @brief Concatenate C string and string.
6063  * @param __lhs First string.
6064  * @param __rhs Last string.
6065  * @return New string with value of @a __lhs followed by @a __rhs.
6066  */
6067  template<typename _CharT, typename _Traits, typename _Alloc>
6068  basic_string<_CharT,_Traits,_Alloc>
6069  operator+(const _CharT* __lhs,
6070  const basic_string<_CharT,_Traits,_Alloc>& __rhs);
6071 
6072  /**
6073  * @brief Concatenate character and string.
6074  * @param __lhs First string.
6075  * @param __rhs Last string.
6076  * @return New string with @a __lhs followed by @a __rhs.
6077  */
6078  template<typename _CharT, typename _Traits, typename _Alloc>
6079  basic_string<_CharT,_Traits,_Alloc>
6080  operator+(_CharT __lhs, const basic_string<_CharT,_Traits,_Alloc>& __rhs);
6081 
6082  /**
6083  * @brief Concatenate string and C string.
6084  * @param __lhs First string.
6085  * @param __rhs Last string.
6086  * @return New string with @a __lhs followed by @a __rhs.
6087  */
6088  template<typename _CharT, typename _Traits, typename _Alloc>
6089  inline basic_string<_CharT, _Traits, _Alloc>
6091  const _CharT* __rhs)
6092  {
6094  __str.append(__rhs);
6095  return __str;
6096  }
6097 
6098  /**
6099  * @brief Concatenate string and character.
6100  * @param __lhs First string.
6101  * @param __rhs Last string.
6102  * @return New string with @a __lhs followed by @a __rhs.
6103  */
6104  template<typename _CharT, typename _Traits, typename _Alloc>
6105  inline basic_string<_CharT, _Traits, _Alloc>
6107  {
6108  typedef basic_string<_CharT, _Traits, _Alloc> __string_type;
6109  typedef typename __string_type::size_type __size_type;
6110  __string_type __str(__lhs);
6111  __str.append(__size_type(1), __rhs);
6112  return __str;
6113  }
6114 
6115 #if __cplusplus >= 201103L
6116  template<typename _CharT, typename _Traits, typename _Alloc>
6117  inline basic_string<_CharT, _Traits, _Alloc>
6118  operator+(basic_string<_CharT, _Traits, _Alloc>&& __lhs,
6119  const basic_string<_CharT, _Traits, _Alloc>& __rhs)
6120  { return std::move(__lhs.append(__rhs)); }
6121 
6122  template<typename _CharT, typename _Traits, typename _Alloc>
6123  inline basic_string<_CharT, _Traits, _Alloc>
6124  operator+(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
6125  basic_string<_CharT, _Traits, _Alloc>&& __rhs)
6126  { return std::move(__rhs.insert(0, __lhs)); }
6127 
6128  template<typename _CharT, typename _Traits, typename _Alloc>
6129  inline basic_string<_CharT, _Traits, _Alloc>
6130  operator+(basic_string<_CharT, _Traits, _Alloc>&& __lhs,
6131  basic_string<_CharT, _Traits, _Alloc>&& __rhs)
6132  {
6133 #if _GLIBCXX_USE_CXX11_ABI
6134  using _Alloc_traits = allocator_traits<_Alloc>;
6135  bool __use_rhs = false;
6136  if _GLIBCXX17_CONSTEXPR (typename _Alloc_traits::is_always_equal{})
6137  __use_rhs = true;
6138  else if (__lhs.get_allocator() == __rhs.get_allocator())
6139  __use_rhs = true;
6140  if (__use_rhs)
6141 #endif
6142  {
6143  const auto __size = __lhs.size() + __rhs.size();
6144  if (__size > __lhs.capacity() && __size <= __rhs.capacity())
6145  return std::move(__rhs.insert(0, __lhs));
6146  }
6147  return std::move(__lhs.append(__rhs));
6148  }
6149 
6150  template<typename _CharT, typename _Traits, typename _Alloc>
6151  inline basic_string<_CharT, _Traits, _Alloc>
6152  operator+(const _CharT* __lhs,
6153  basic_string<_CharT, _Traits, _Alloc>&& __rhs)
6154  { return std::move(__rhs.insert(0, __lhs)); }
6155 
6156  template<typename _CharT, typename _Traits, typename _Alloc>
6157  inline basic_string<_CharT, _Traits, _Alloc>
6158  operator+(_CharT __lhs,
6159  basic_string<_CharT, _Traits, _Alloc>&& __rhs)
6160  { return std::move(__rhs.insert(0, 1, __lhs)); }
6161 
6162  template<typename _CharT, typename _Traits, typename _Alloc>
6163  inline basic_string<_CharT, _Traits, _Alloc>
6164  operator+(basic_string<_CharT, _Traits, _Alloc>&& __lhs,
6165  const _CharT* __rhs)
6166  { return std::move(__lhs.append(__rhs)); }
6167 
6168  template<typename _CharT, typename _Traits, typename _Alloc>
6169  inline basic_string<_CharT, _Traits, _Alloc>
6170  operator+(basic_string<_CharT, _Traits, _Alloc>&& __lhs,
6171  _CharT __rhs)
6172  { return std::move(__lhs.append(1, __rhs)); }
6173 #endif
6174 
6175  // operator ==
6176  /**
6177  * @brief Test equivalence of two strings.
6178  * @param __lhs First string.
6179  * @param __rhs Second string.
6180  * @return True if @a __lhs.compare(@a __rhs) == 0. False otherwise.
6181  */
6182  template<typename _CharT, typename _Traits, typename _Alloc>
6183  inline bool
6184  operator==(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
6186  _GLIBCXX_NOEXCEPT
6187  { return __lhs.compare(__rhs) == 0; }
6188 
6189  template<typename _CharT>
6190  inline
6191  typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value, bool>::__type
6192  operator==(const basic_string<_CharT>& __lhs,
6193  const basic_string<_CharT>& __rhs) _GLIBCXX_NOEXCEPT
6194  { return (__lhs.size() == __rhs.size()
6195  && !std::char_traits<_CharT>::compare(__lhs.data(), __rhs.data(),
6196  __lhs.size())); }
6197 
6198  /**
6199  * @brief Test equivalence of string and C string.
6200  * @param __lhs String.
6201  * @param __rhs C string.
6202  * @return True if @a __lhs.compare(@a __rhs) == 0. False otherwise.
6203  */
6204  template<typename _CharT, typename _Traits, typename _Alloc>
6205  inline bool
6206  operator==(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
6207  const _CharT* __rhs)
6208  { return __lhs.compare(__rhs) == 0; }
6209 
6210 #if __cpp_lib_three_way_comparison
6211  /**
6212  * @brief Three-way comparison of a string and a C string.
6213  * @param __lhs A string.
6214  * @param __rhs A null-terminated string.
6215  * @return A value indicating whether `__lhs` is less than, equal to,
6216  * greater than, or incomparable with `__rhs`.
6217  */
6218  template<typename _CharT, typename _Traits, typename _Alloc>
6219  inline auto
6220  operator<=>(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
6221  const basic_string<_CharT, _Traits, _Alloc>& __rhs) noexcept
6222  -> decltype(__detail::__char_traits_cmp_cat<_Traits>(0))
6223  { return __detail::__char_traits_cmp_cat<_Traits>(__lhs.compare(__rhs)); }
6224 
6225  /**
6226  * @brief Three-way comparison of a string and a C string.
6227  * @param __lhs A string.
6228  * @param __rhs A null-terminated string.
6229  * @return A value indicating whether `__lhs` is less than, equal to,
6230  * greater than, or incomparable with `__rhs`.
6231  */
6232  template<typename _CharT, typename _Traits, typename _Alloc>
6233  inline auto
6234  operator<=>(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
6235  const _CharT* __rhs) noexcept
6236  -> decltype(__detail::__char_traits_cmp_cat<_Traits>(0))
6237  { return __detail::__char_traits_cmp_cat<_Traits>(__lhs.compare(__rhs)); }
6238 #else
6239  /**
6240  * @brief Test equivalence of C string and string.
6241  * @param __lhs C string.
6242  * @param __rhs String.
6243  * @return True if @a __rhs.compare(@a __lhs) == 0. False otherwise.
6244  */
6245  template<typename _CharT, typename _Traits, typename _Alloc>
6246  inline bool
6247  operator==(const _CharT* __lhs,
6249  { return __rhs.compare(__lhs) == 0; }
6250 
6251  // operator !=
6252  /**
6253  * @brief Test difference of two strings.
6254  * @param __lhs First string.
6255  * @param __rhs Second string.
6256  * @return True if @a __lhs.compare(@a __rhs) != 0. False otherwise.
6257  */
6258  template<typename _CharT, typename _Traits, typename _Alloc>
6259  inline bool
6260  operator!=(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
6262  _GLIBCXX_NOEXCEPT
6263  { return !(__lhs == __rhs); }
6264 
6265  /**
6266  * @brief Test difference of C string and string.
6267  * @param __lhs C string.
6268  * @param __rhs String.
6269  * @return True if @a __rhs.compare(@a __lhs) != 0. False otherwise.
6270  */
6271  template<typename _CharT, typename _Traits, typename _Alloc>
6272  inline bool
6273  operator!=(const _CharT* __lhs,
6275  { return !(__lhs == __rhs); }
6276 
6277  /**
6278  * @brief Test difference of string and C string.
6279  * @param __lhs String.
6280  * @param __rhs C string.
6281  * @return True if @a __lhs.compare(@a __rhs) != 0. False otherwise.
6282  */
6283  template<typename _CharT, typename _Traits, typename _Alloc>
6284  inline bool
6285  operator!=(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
6286  const _CharT* __rhs)
6287  { return !(__lhs == __rhs); }
6288 
6289  // operator <
6290  /**
6291  * @brief Test if string precedes string.
6292  * @param __lhs First string.
6293  * @param __rhs Second string.
6294  * @return True if @a __lhs precedes @a __rhs. False otherwise.
6295  */
6296  template<typename _CharT, typename _Traits, typename _Alloc>
6297  inline bool
6298  operator<(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
6300  _GLIBCXX_NOEXCEPT
6301  { return __lhs.compare(__rhs) < 0; }
6302 
6303  /**
6304  * @brief Test if string precedes C string.
6305  * @param __lhs String.
6306  * @param __rhs C string.
6307  * @return True if @a __lhs precedes @a __rhs. False otherwise.
6308  */
6309  template<typename _CharT, typename _Traits, typename _Alloc>
6310  inline bool
6311  operator<(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
6312  const _CharT* __rhs)
6313  { return __lhs.compare(__rhs) < 0; }
6314 
6315  /**
6316  * @brief Test if C string precedes string.
6317  * @param __lhs C string.
6318  * @param __rhs String.
6319  * @return True if @a __lhs precedes @a __rhs. False otherwise.
6320  */
6321  template<typename _CharT, typename _Traits, typename _Alloc>
6322  inline bool
6323  operator<(const _CharT* __lhs,
6325  { return __rhs.compare(__lhs) > 0; }
6326 
6327  // operator >
6328  /**
6329  * @brief Test if string follows string.
6330  * @param __lhs First string.
6331  * @param __rhs Second string.
6332  * @return True if @a __lhs follows @a __rhs. False otherwise.
6333  */
6334  template<typename _CharT, typename _Traits, typename _Alloc>
6335  inline bool
6338  _GLIBCXX_NOEXCEPT
6339  { return __lhs.compare(__rhs) > 0; }
6340 
6341  /**
6342  * @brief Test if string follows C string.
6343  * @param __lhs String.
6344  * @param __rhs C string.
6345  * @return True if @a __lhs follows @a __rhs. False otherwise.
6346  */
6347  template<typename _CharT, typename _Traits, typename _Alloc>
6348  inline bool
6350  const _CharT* __rhs)
6351  { return __lhs.compare(__rhs) > 0; }
6352 
6353  /**
6354  * @brief Test if C string follows string.
6355  * @param __lhs C string.
6356  * @param __rhs String.
6357  * @return True if @a __lhs follows @a __rhs. False otherwise.
6358  */
6359  template<typename _CharT, typename _Traits, typename _Alloc>
6360  inline bool
6361  operator>(const _CharT* __lhs,
6363  { return __rhs.compare(__lhs) < 0; }
6364 
6365  // operator <=
6366  /**
6367  * @brief Test if string doesn't follow string.
6368  * @param __lhs First string.
6369  * @param __rhs Second string.
6370  * @return True if @a __lhs doesn't follow @a __rhs. False otherwise.
6371  */
6372  template<typename _CharT, typename _Traits, typename _Alloc>
6373  inline bool
6374  operator<=(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
6376  _GLIBCXX_NOEXCEPT
6377  { return __lhs.compare(__rhs) <= 0; }
6378 
6379  /**
6380  * @brief Test if string doesn't follow C string.
6381  * @param __lhs String.
6382  * @param __rhs C string.
6383  * @return True if @a __lhs doesn't follow @a __rhs. False otherwise.
6384  */
6385  template<typename _CharT, typename _Traits, typename _Alloc>
6386  inline bool
6387  operator<=(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
6388  const _CharT* __rhs)
6389  { return __lhs.compare(__rhs) <= 0; }
6390 
6391  /**
6392  * @brief Test if C string doesn't follow string.
6393  * @param __lhs C string.
6394  * @param __rhs String.
6395  * @return True if @a __lhs doesn't follow @a __rhs. False otherwise.
6396  */
6397  template<typename _CharT, typename _Traits, typename _Alloc>
6398  inline bool
6399  operator<=(const _CharT* __lhs,
6401  { return __rhs.compare(__lhs) >= 0; }
6402 
6403  // operator >=
6404  /**
6405  * @brief Test if string doesn't precede string.
6406  * @param __lhs First string.
6407  * @param __rhs Second string.
6408  * @return True if @a __lhs doesn't precede @a __rhs. False otherwise.
6409  */
6410  template<typename _CharT, typename _Traits, typename _Alloc>
6411  inline bool
6412  operator>=(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
6414  _GLIBCXX_NOEXCEPT
6415  { return __lhs.compare(__rhs) >= 0; }
6416 
6417  /**
6418  * @brief Test if string doesn't precede C string.
6419  * @param __lhs String.
6420  * @param __rhs C string.
6421  * @return True if @a __lhs doesn't precede @a __rhs. False otherwise.
6422  */
6423  template<typename _CharT, typename _Traits, typename _Alloc>
6424  inline bool
6425  operator>=(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
6426  const _CharT* __rhs)
6427  { return __lhs.compare(__rhs) >= 0; }
6428 
6429  /**
6430  * @brief Test if C string doesn't precede string.
6431  * @param __lhs C string.
6432  * @param __rhs String.
6433  * @return True if @a __lhs doesn't precede @a __rhs. False otherwise.
6434  */
6435  template<typename _CharT, typename _Traits, typename _Alloc>
6436  inline bool
6437  operator>=(const _CharT* __lhs,
6439  { return __rhs.compare(__lhs) <= 0; }
6440 #endif // three-way comparison
6441 
6442  /**
6443  * @brief Swap contents of two strings.
6444  * @param __lhs First string.
6445  * @param __rhs Second string.
6446  *
6447  * Exchanges the contents of @a __lhs and @a __rhs in constant time.
6448  */
6449  template<typename _CharT, typename _Traits, typename _Alloc>
6450  inline void
6453  _GLIBCXX_NOEXCEPT_IF(noexcept(__lhs.swap(__rhs)))
6454  { __lhs.swap(__rhs); }
6455 
6456 
6457  /**
6458  * @brief Read stream into a string.
6459  * @param __is Input stream.
6460  * @param __str Buffer to store into.
6461  * @return Reference to the input stream.
6462  *
6463  * Stores characters from @a __is into @a __str until whitespace is
6464  * found, the end of the stream is encountered, or str.max_size()
6465  * is reached. If is.width() is non-zero, that is the limit on the
6466  * number of characters stored into @a __str. Any previous
6467  * contents of @a __str are erased.
6468  */
6469  template<typename _CharT, typename _Traits, typename _Alloc>
6470  basic_istream<_CharT, _Traits>&
6471  operator>>(basic_istream<_CharT, _Traits>& __is,
6472  basic_string<_CharT, _Traits, _Alloc>& __str);
6473 
6474  template<>
6475  basic_istream<char>&
6477 
6478  /**
6479  * @brief Write string to a stream.
6480  * @param __os Output stream.
6481  * @param __str String to write out.
6482  * @return Reference to the output stream.
6483  *
6484  * Output characters of @a __str into os following the same rules as for
6485  * writing a C string.
6486  */
6487  template<typename _CharT, typename _Traits, typename _Alloc>
6489  operator<<(basic_ostream<_CharT, _Traits>& __os,
6491  {
6492  // _GLIBCXX_RESOLVE_LIB_DEFECTS
6493  // 586. string inserter not a formatted function
6494  return __ostream_insert(__os, __str.data(), __str.size());
6495  }
6496 
6497  /**
6498  * @brief Read a line from stream into a string.
6499  * @param __is Input stream.
6500  * @param __str Buffer to store into.
6501  * @param __delim Character marking end of line.
6502  * @return Reference to the input stream.
6503  *
6504  * Stores characters from @a __is into @a __str until @a __delim is
6505  * found, the end of the stream is encountered, or str.max_size()
6506  * is reached. Any previous contents of @a __str are erased. If
6507  * @a __delim is encountered, it is extracted but not stored into
6508  * @a __str.
6509  */
6510  template<typename _CharT, typename _Traits, typename _Alloc>
6511  basic_istream<_CharT, _Traits>&
6512  getline(basic_istream<_CharT, _Traits>& __is,
6513  basic_string<_CharT, _Traits, _Alloc>& __str, _CharT __delim);
6514 
6515  /**
6516  * @brief Read a line from stream into a string.
6517  * @param __is Input stream.
6518  * @param __str Buffer to store into.
6519  * @return Reference to the input stream.
6520  *
6521  * Stores characters from is into @a __str until &apos;\n&apos; is
6522  * found, the end of the stream is encountered, or str.max_size()
6523  * is reached. Any previous contents of @a __str are erased. If
6524  * end of line is encountered, it is extracted but not stored into
6525  * @a __str.
6526  */
6527  template<typename _CharT, typename _Traits, typename _Alloc>
6528  inline basic_istream<_CharT, _Traits>&
6531  { return std::getline(__is, __str, __is.widen('\n')); }
6532 
6533 #if __cplusplus >= 201103L
6534  /// Read a line from an rvalue stream into a string.
6535  template<typename _CharT, typename _Traits, typename _Alloc>
6536  inline basic_istream<_CharT, _Traits>&
6538  basic_string<_CharT, _Traits, _Alloc>& __str, _CharT __delim)
6539  { return std::getline(__is, __str, __delim); }
6540 
6541  /// Read a line from an rvalue stream into a string.
6542  template<typename _CharT, typename _Traits, typename _Alloc>
6543  inline basic_istream<_CharT, _Traits>&
6546  { return std::getline(__is, __str); }
6547 #endif
6548 
6549  template<>
6550  basic_istream<char>&
6551  getline(basic_istream<char>& __in, basic_string<char>& __str,
6552  char __delim);
6553 
6554 #ifdef _GLIBCXX_USE_WCHAR_T
6555  template<>
6556  basic_istream<wchar_t>&
6557  getline(basic_istream<wchar_t>& __in, basic_string<wchar_t>& __str,
6558  wchar_t __delim);
6559 #endif
6560 
6561 _GLIBCXX_END_NAMESPACE_VERSION
6562 } // namespace
6563 
6564 #if __cplusplus >= 201103L
6565 
6566 #include <ext/string_conversions.h>
6567 #include <bits/charconv.h>
6568 
6569 namespace std _GLIBCXX_VISIBILITY(default)
6570 {
6571 _GLIBCXX_BEGIN_NAMESPACE_VERSION
6572 _GLIBCXX_BEGIN_NAMESPACE_CXX11
6573 
6574 #if _GLIBCXX_USE_C99_STDLIB
6575  // 21.4 Numeric Conversions [string.conversions].
6576  inline int
6577  stoi(const string& __str, size_t* __idx = 0, int __base = 10)
6578  { return __gnu_cxx::__stoa<long, int>(&std::strtol, "stoi", __str.c_str(),
6579  __idx, __base); }
6580 
6581  inline long
6582  stol(const string& __str, size_t* __idx = 0, int __base = 10)
6583  { return __gnu_cxx::__stoa(&std::strtol, "stol", __str.c_str(),
6584  __idx, __base); }
6585 
6586  inline unsigned long
6587  stoul(const string& __str, size_t* __idx = 0, int __base = 10)
6588  { return __gnu_cxx::__stoa(&std::strtoul, "stoul", __str.c_str(),
6589  __idx, __base); }
6590 
6591  inline long long
6592  stoll(const string& __str, size_t* __idx = 0, int __base = 10)
6593  { return __gnu_cxx::__stoa(&std::strtoll, "stoll", __str.c_str(),
6594  __idx, __base); }
6595 
6596  inline unsigned long long
6597  stoull(const string& __str, size_t* __idx = 0, int __base = 10)
6598  { return __gnu_cxx::__stoa(&std::strtoull, "stoull", __str.c_str(),
6599  __idx, __base); }
6600 
6601  // NB: strtof vs strtod.
6602  inline float
6603  stof(const string& __str, size_t* __idx = 0)
6604  { return __gnu_cxx::__stoa(&std::strtof, "stof", __str.c_str(), __idx); }
6605 
6606  inline double
6607  stod(const string& __str, size_t* __idx = 0)
6608  { return __gnu_cxx::__stoa(&std::strtod, "stod", __str.c_str(), __idx); }
6609 
6610  inline long double
6611  stold(const string& __str, size_t* __idx = 0)
6612  { return __gnu_cxx::__stoa(&std::strtold, "stold", __str.c_str(), __idx); }
6613 #endif // _GLIBCXX_USE_C99_STDLIB
6614 
6615  // DR 1261. Insufficent overloads for to_string / to_wstring
6616 
6617  inline string
6618  to_string(int __val)
6619  {
6620  const bool __neg = __val < 0;
6621  const unsigned __uval = __neg ? (unsigned)~__val + 1u : __val;
6622  const auto __len = __detail::__to_chars_len(__uval);
6623  string __str(__neg + __len, '-');
6624  __detail::__to_chars_10_impl(&__str[__neg], __len, __uval);
6625  return __str;
6626  }
6627 
6628  inline string
6629  to_string(unsigned __val)
6630  {
6631  string __str(__detail::__to_chars_len(__val), '\0');
6632  __detail::__to_chars_10_impl(&__str[0], __str.size(), __val);
6633  return __str;
6634  }
6635 
6636  inline string
6637  to_string(long __val)
6638  {
6639  const bool __neg = __val < 0;
6640  const unsigned long __uval = __neg ? (unsigned long)~__val + 1ul : __val;
6641  const auto __len = __detail::__to_chars_len(__uval);
6642  string __str(__neg + __len, '-');
6643  __detail::__to_chars_10_impl(&__str[__neg], __len, __uval);
6644  return __str;
6645  }
6646 
6647  inline string
6648  to_string(unsigned long __val)
6649  {
6650  string __str(__detail::__to_chars_len(__val), '\0');
6651  __detail::__to_chars_10_impl(&__str[0], __str.size(), __val);
6652  return __str;
6653  }
6654 
6655  inline string
6656  to_string(long long __val)
6657  {
6658  const bool __neg = __val < 0;
6659  const unsigned long long __uval
6660  = __neg ? (unsigned long long)~__val + 1ull : __val;
6661  const auto __len = __detail::__to_chars_len(__uval);
6662  string __str(__neg + __len, '-');
6663  __detail::__to_chars_10_impl(&__str[__neg], __len, __uval);
6664  return __str;
6665  }
6666 
6667  inline string
6668  to_string(unsigned long long __val)
6669  {
6670  string __str(__detail::__to_chars_len(__val), '\0');
6671  __detail::__to_chars_10_impl(&__str[0], __str.size(), __val);
6672  return __str;
6673  }
6674 
6675 #if _GLIBCXX_USE_C99_STDIO
6676  // NB: (v)snprintf vs sprintf.
6677 
6678  inline string
6679  to_string(float __val)
6680  {
6681  const int __n =
6682  __gnu_cxx::__numeric_traits<float>::__max_exponent10 + 20;
6683  return __gnu_cxx::__to_xstring<string>(&std::vsnprintf, __n,
6684  "%f", __val);
6685  }
6686 
6687  inline string
6688  to_string(double __val)
6689  {
6690  const int __n =
6691  __gnu_cxx::__numeric_traits<double>::__max_exponent10 + 20;
6692  return __gnu_cxx::__to_xstring<string>(&std::vsnprintf, __n,
6693  "%f", __val);
6694  }
6695 
6696  inline string
6697  to_string(long double __val)
6698  {
6699  const int __n =
6700  __gnu_cxx::__numeric_traits<long double>::__max_exponent10 + 20;
6701  return __gnu_cxx::__to_xstring<string>(&std::vsnprintf, __n,
6702  "%Lf", __val);
6703  }
6704 #endif // _GLIBCXX_USE_C99_STDIO
6705 
6706 #if defined(_GLIBCXX_USE_WCHAR_T) && _GLIBCXX_USE_C99_WCHAR
6707  inline int
6708  stoi(const wstring& __str, size_t* __idx = 0, int __base = 10)
6709  { return __gnu_cxx::__stoa<long, int>(&std::wcstol, "stoi", __str.c_str(),
6710  __idx, __base); }
6711 
6712  inline long
6713  stol(const wstring& __str, size_t* __idx = 0, int __base = 10)
6714  { return __gnu_cxx::__stoa(&std::wcstol, "stol", __str.c_str(),
6715  __idx, __base); }
6716 
6717  inline unsigned long
6718  stoul(const wstring& __str, size_t* __idx = 0, int __base = 10)
6719  { return __gnu_cxx::__stoa(&std::wcstoul, "stoul", __str.c_str(),
6720  __idx, __base); }
6721 
6722  inline long long
6723  stoll(const wstring& __str, size_t* __idx = 0, int __base = 10)
6724  { return __gnu_cxx::__stoa(&std::wcstoll, "stoll", __str.c_str(),
6725  __idx, __base); }
6726 
6727  inline unsigned long long
6728  stoull(const wstring& __str, size_t* __idx = 0, int __base = 10)
6729  { return __gnu_cxx::__stoa(&std::wcstoull, "stoull", __str.c_str(),
6730  __idx, __base); }
6731 
6732  // NB: wcstof vs wcstod.
6733  inline float
6734  stof(const wstring& __str, size_t* __idx = 0)
6735  { return __gnu_cxx::__stoa(&std::wcstof, "stof", __str.c_str(), __idx); }
6736 
6737  inline double
6738  stod(const wstring& __str, size_t* __idx = 0)
6739  { return __gnu_cxx::__stoa(&std::wcstod, "stod", __str.c_str(), __idx); }
6740 
6741  inline long double
6742  stold(const wstring& __str, size_t* __idx = 0)
6743  { return __gnu_cxx::__stoa(&std::wcstold, "stold", __str.c_str(), __idx); }
6744 
6745 #ifndef _GLIBCXX_HAVE_BROKEN_VSWPRINTF
6746  // DR 1261.
6747  inline wstring
6748  to_wstring(int __val)
6749  { return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf, 4 * sizeof(int),
6750  L"%d", __val); }
6751 
6752  inline wstring
6753  to_wstring(unsigned __val)
6754  { return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf,
6755  4 * sizeof(unsigned),
6756  L"%u", __val); }
6757 
6758  inline wstring
6759  to_wstring(long __val)
6760  { return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf, 4 * sizeof(long),
6761  L"%ld", __val); }
6762 
6763  inline wstring
6764  to_wstring(unsigned long __val)
6765  { return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf,
6766  4 * sizeof(unsigned long),
6767  L"%lu", __val); }
6768 
6769  inline wstring
6770  to_wstring(long long __val)
6771  { return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf,
6772  4 * sizeof(long long),
6773  L"%lld", __val); }
6774 
6775  inline wstring
6776  to_wstring(unsigned long long __val)
6777  { return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf,
6778  4 * sizeof(unsigned long long),
6779  L"%llu", __val); }
6780 
6781  inline wstring
6782  to_wstring(float __val)
6783  {
6784  const int __n =
6785  __gnu_cxx::__numeric_traits<float>::__max_exponent10 + 20;
6786  return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf, __n,
6787  L"%f", __val);
6788  }
6789 
6790  inline wstring
6791  to_wstring(double __val)
6792  {
6793  const int __n =
6794  __gnu_cxx::__numeric_traits<double>::__max_exponent10 + 20;
6795  return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf, __n,
6796  L"%f", __val);
6797  }
6798 
6799  inline wstring
6800  to_wstring(long double __val)
6801  {
6802  const int __n =
6803  __gnu_cxx::__numeric_traits<long double>::__max_exponent10 + 20;
6804  return __gnu_cxx::__to_xstring<wstring>(&std::vswprintf, __n,
6805  L"%Lf", __val);
6806  }
6807 #endif // _GLIBCXX_HAVE_BROKEN_VSWPRINTF
6808 #endif // _GLIBCXX_USE_WCHAR_T && _GLIBCXX_USE_C99_WCHAR
6809 
6810 _GLIBCXX_END_NAMESPACE_CXX11
6811 _GLIBCXX_END_NAMESPACE_VERSION
6812 } // namespace
6813 
6814 #endif /* C++11 */
6815 
6816 #if __cplusplus >= 201103L
6817 
6818 #include <bits/functional_hash.h>
6819 
6820 namespace std _GLIBCXX_VISIBILITY(default)
6821 {
6822 _GLIBCXX_BEGIN_NAMESPACE_VERSION
6823 
6824  // DR 1182.
6825 
6826 #ifndef _GLIBCXX_COMPATIBILITY_CXX0X
6827  /// std::hash specialization for string.
6828  template<>
6829  struct hash<string>
6830  : public __hash_base<size_t, string>
6831  {
6832  size_t
6833  operator()(const string& __s) const noexcept
6834  { return std::_Hash_impl::hash(__s.data(), __s.length()); }
6835  };
6836 
6837  template<>
6838  struct __is_fast_hash<hash<string>> : std::false_type
6839  { };
6840 
6841 #ifdef _GLIBCXX_USE_WCHAR_T
6842  /// std::hash specialization for wstring.
6843  template<>
6844  struct hash<wstring>
6845  : public __hash_base<size_t, wstring>
6846  {
6847  size_t
6848  operator()(const wstring& __s) const noexcept
6849  { return std::_Hash_impl::hash(__s.data(),
6850  __s.length() * sizeof(wchar_t)); }
6851  };
6852 
6853  template<>
6854  struct __is_fast_hash<hash<wstring>> : std::false_type
6855  { };
6856 #endif
6857 #endif /* _GLIBCXX_COMPATIBILITY_CXX0X */
6858 
6859 #ifdef _GLIBCXX_USE_CHAR8_T
6860  /// std::hash specialization for u8string.
6861  template<>
6862  struct hash<u8string>
6863  : public __hash_base<size_t, u8string>
6864  {
6865  size_t
6866  operator()(const u8string& __s) const noexcept
6867  { return std::_Hash_impl::hash(__s.data(),
6868  __s.length() * sizeof(char8_t)); }
6869  };
6870 
6871  template<>
6872  struct __is_fast_hash<hash<u8string>> : std::false_type
6873  { };
6874 #endif
6875 
6876  /// std::hash specialization for u16string.
6877  template<>
6878  struct hash<u16string>
6879  : public __hash_base<size_t, u16string>
6880  {
6881  size_t
6882  operator()(const u16string& __s) const noexcept
6883  { return std::_Hash_impl::hash(__s.data(),
6884  __s.length() * sizeof(char16_t)); }
6885  };
6886 
6887  template<>
6888  struct __is_fast_hash<hash<u16string>> : std::false_type
6889  { };
6890 
6891  /// std::hash specialization for u32string.
6892  template<>
6893  struct hash<u32string>
6894  : public __hash_base<size_t, u32string>
6895  {
6896  size_t
6897  operator()(const u32string& __s) const noexcept
6898  { return std::_Hash_impl::hash(__s.data(),
6899  __s.length() * sizeof(char32_t)); }
6900  };
6901 
6902  template<>
6903  struct __is_fast_hash<hash<u32string>> : std::false_type
6904  { };
6905 
6906 #if __cplusplus >= 201402L
6907 
6908 #define __cpp_lib_string_udls 201304
6909 
6910  inline namespace literals
6911  {
6912  inline namespace string_literals
6913  {
6914 #pragma GCC diagnostic push
6915 #pragma GCC diagnostic ignored "-Wliteral-suffix"
6916  _GLIBCXX_DEFAULT_ABI_TAG
6917  inline basic_string<char>
6918  operator""s(const char* __str, size_t __len)
6919  { return basic_string<char>{__str, __len}; }
6920 
6921 #ifdef _GLIBCXX_USE_WCHAR_T
6922  _GLIBCXX_DEFAULT_ABI_TAG
6923  inline basic_string<wchar_t>
6924  operator""s(const wchar_t* __str, size_t __len)
6925  { return basic_string<wchar_t>{__str, __len}; }
6926 #endif
6927 
6928 #ifdef _GLIBCXX_USE_CHAR8_T
6929  _GLIBCXX_DEFAULT_ABI_TAG
6930  inline basic_string<char8_t>
6931  operator""s(const char8_t* __str, size_t __len)
6932  { return basic_string<char8_t>{__str, __len}; }
6933 #endif
6934 
6935  _GLIBCXX_DEFAULT_ABI_TAG
6936  inline basic_string<char16_t>
6937  operator""s(const char16_t* __str, size_t __len)
6938  { return basic_string<char16_t>{__str, __len}; }
6939 
6940  _GLIBCXX_DEFAULT_ABI_TAG
6941  inline basic_string<char32_t>
6942  operator""s(const char32_t* __str, size_t __len)
6943  { return basic_string<char32_t>{__str, __len}; }
6944 
6945 #pragma GCC diagnostic pop
6946  } // inline namespace string_literals
6947  } // inline namespace literals
6948 
6949 #if __cplusplus >= 201703L
6950  namespace __detail::__variant
6951  {
6952  template<typename> struct _Never_valueless_alt; // see <variant>
6953 
6954  // Provide the strong exception-safety guarantee when emplacing a
6955  // basic_string into a variant, but only if moving the string cannot throw.
6956  template<typename _Tp, typename _Traits, typename _Alloc>
6957  struct _Never_valueless_alt<std::basic_string<_Tp, _Traits, _Alloc>>
6958  : __and_<
6959  is_nothrow_move_constructible<std::basic_string<_Tp, _Traits, _Alloc>>,
6960  is_nothrow_move_assignable<std::basic_string<_Tp, _Traits, _Alloc>>
6961  >::type
6962  { };
6963  } // namespace __detail::__variant
6964 #endif // C++17
6965 #endif // C++14
6966 
6967 _GLIBCXX_END_NAMESPACE_VERSION
6968 } // namespace std
6969 
6970 #endif // C++11
6971 
6972 #endif /* _BASIC_STRING_H */
constexpr complex< _Tp > operator+(const complex< _Tp > &__x, const complex< _Tp > &__y)
Return new complex value x plus y.
Definition: complex:332
typename enable_if< _Cond, _Tp >::type enable_if_t
Alias template for enable_if.
Definition: type_traits:2514
constexpr _Tp * __addressof(_Tp &__r) noexcept
Same as C++11 std::addressof.
Definition: move.h:49
constexpr std::remove_reference< _Tp >::type && move(_Tp &&__t) noexcept
Convert a value to an rvalue.
Definition: move.h:101
void swap(any &__x, any &__y) noexcept
Exchange the states of two any objects.
Definition: any:412
constexpr const _Tp & min(const _Tp &, const _Tp &)
This does what you think it does.
Definition: stl_algobase.h:230
basic_string< wchar_t > wstring
A string of wchar_t.
Definition: stringfwd.h:83
ISO C++ entities toplevel namespace is std.
std::basic_istream< _CharT, _Traits > & operator>>(std::basic_istream< _CharT, _Traits > &__is, bitset< _Nb > &__x)
Global I/O operators for bitsets.
Definition: bitset:1472
basic_istream< _CharT, _Traits > & getline(basic_istream< _CharT, _Traits > &__is, basic_string< _CharT, _Traits, _Alloc > &__str, _CharT __delim)
Read a line from stream into a string.
constexpr _Iterator __base(_Iterator __it)
initializer_list
char_type widen(char __c) const
Widens characters.
Definition: basic_ios.h:449
Template class basic_ostream.
Definition: ostream:59
Primary class template hash.
integral_constant
Definition: type_traits:58
is_same
Definition: type_traits:1360
Uniform interface to all allocator types.
Managing sequences of characters and character-like objects.
const_reverse_iterator crbegin() const noexcept
void swap(basic_string &__s) noexcept(/*conditional */)
Swap contents with another string.
basic_string & assign(size_type __n, _CharT __c)
Set value to multiple characters.
_If_sv< _Tp, basic_string & > append(const _Tp &__svt)
Append a string_view.
void push_back(_CharT __c)
Append a single character.
const_iterator cend() const noexcept
size_type find(const _CharT *__s, size_type __pos=0) const noexcept
Find position of a C string.
basic_string(_InputIterator __beg, _InputIterator __end, const _Alloc &__a=_Alloc())
Construct string as copy of a range.
basic_string & replace(size_type __pos, size_type __n1, size_type __n2, _CharT __c)
Replace characters with multiple characters.
basic_string & replace(iterator __i1, iterator __i2, const _CharT *__s)
Replace range of characters with C string.
_If_sv< _Tp, size_type > find_last_of(const _Tp &__svt, size_type __pos=npos) const noexcept(is_same< _Tp, __sv_type >::value)
Find last position of a character of string.
size_type find_first_of(const basic_string &__str, size_type __pos=0) const noexcept
Find position of a character of string.
basic_string & append(_InputIterator __first, _InputIterator __last)
Append a range of characters.
basic_string & operator=(initializer_list< _CharT > __l)
Set value to string constructed from initializer list.
_If_sv< _Tp, size_type > find(const _Tp &__svt, size_type __pos=0) const noexcept(is_same< _Tp, __sv_type >::value)
Find position of a string_view.
basic_string(const _Alloc &__a)
Construct an empty string using allocator a.
const _CharT * c_str() const noexcept
Return const pointer to null-terminated contents.
basic_string & assign(const _CharT *__s)
Set value to contents of a C string.
size_type find_last_of(const _CharT *__s, size_type __pos=npos) const noexcept
Find last position of a character of C string.
_If_sv< _Tp, basic_string & > append(const _Tp &__svt, size_type __pos, size_type __n=npos)
Append a range of characters from a string_view.
void insert(iterator __p, initializer_list< _CharT > __l)
Insert an initializer_list of characters.
size_type rfind(const _CharT *__s, size_type __pos=npos) const noexcept
Find last position of a C string.
basic_string substr(size_type __pos=0, size_type __n=npos) const
Get a substring.
iterator erase(iterator __position)
Remove one character.
size_type find(const _CharT *__s, size_type __pos, size_type __n) const noexcept
Find position of a C substring.
size_type find(const basic_string &__str, size_type __pos=0) const noexcept
Find position of a string.
size_type find_last_not_of(const basic_string &__str, size_type __pos=npos) const noexcept
Find last position of a character not in string.
_If_sv< _Tp, basic_string & > operator=(const _Tp &__svt)
Set value to string constructed from a string_view.
basic_string(const basic_string &__str)
Construct string with copy of value of str.
basic_string & replace(iterator __i1, iterator __i2, size_type __n, _CharT __c)
Replace range of characters with multiple characters.
int compare(const basic_string &__str) const
Compare to a string.
reverse_iterator rend()
_If_sv< _Tp, basic_string & > replace(const_iterator __i1, const_iterator __i2, const _Tp &__svt)
Replace range of characters with string_view.
basic_string & operator=(const _CharT *__s)
Copy contents of s into this string.
size_type find_first_not_of(const basic_string &__str, size_type __pos=0) const noexcept
Find position of a character not in string.
_If_sv< _Tp, basic_string & > insert(size_type __pos, const _Tp &__svt)
Insert a string_view.
basic_string & replace(size_type __pos, size_type __n1, const _CharT *__s)
Replace characters with value of a C string.
const_reference front() const noexcept
size_type find_last_not_of(const _CharT *__s, size_type __pos=npos) const noexcept
Find last position of a character not in C string.
void insert(iterator __p, size_type __n, _CharT __c)
Insert multiple characters.
basic_string & operator+=(const basic_string &__str)
Append a string to this string.
basic_string & assign(const basic_string &__str)
Set value to contents of another string.
basic_string(const _Tp &__t, size_type __pos, size_type __n, const _Alloc &__a=_Alloc())
Construct string from a substring of a string_view.
reverse_iterator rbegin()
basic_string & operator+=(initializer_list< _CharT > __l)
Append an initializer_list of characters.
_If_sv< _Tp, basic_string & > operator+=(const _Tp &__svt)
Append a string_view.
basic_string(initializer_list< _CharT > __l, const _Alloc &__a=_Alloc())
Construct string from an initializer list.
basic_string & replace(size_type __pos, size_type __n, const basic_string &__str)
Replace characters with value from another string.
reference front()
basic_string(const _Tp &__t, const _Alloc &__a=_Alloc())
Construct string from a string_view.
_If_sv< _Tp, basic_string & > replace(size_type __pos, size_type __n, const _Tp &__svt)
Replace range of characters with string_view.
basic_string & assign(_InputIterator __first, _InputIterator __last)
Set value to a range of characters.
void pop_back()
Remove the last character.
basic_string & insert(size_type __pos1, const basic_string &__str)
Insert value of a string.
_If_sv< _Tp, basic_string & > assign(const _Tp &__svt)
Set value from a string_view.
basic_string(basic_string &&__str) noexcept
Move construct string.
size_type copy(_CharT *__s, size_type __n, size_type __pos=0) const
Copy substring into C string.
size_type length() const noexcept
Returns the number of characters in the string, not including any null-termination.
size_type find_last_of(const basic_string &__str, size_type __pos=npos) const noexcept
Find last position of a character of string.
basic_string & replace(iterator __i1, iterator __i2, initializer_list< _CharT > __l)
Replace range of characters with initializer_list.
basic_string & insert(size_type __pos1, const basic_string &__str, size_type __pos2, size_type __n=npos)
Insert a substring.
_If_sv< _Tp, int > compare(const _Tp &__svt) const noexcept(is_same< _Tp, __sv_type >::value)
Compare to a string_view.
_If_sv< _Tp, size_type > rfind(const _Tp &__svt, size_type __pos=npos) const noexcept(is_same< _Tp, __sv_type >::value)
Find last position of a string_view.
size_type size() const noexcept
Returns the number of characters in the string, not including any null-termination.
size_type rfind(const basic_string &__str, size_type __pos=npos) const noexcept
Find last position of a string.
basic_string & assign(initializer_list< _CharT > __l)
Set value to an initializer_list of characters.
basic_string(size_type __n, _CharT __c, const _Alloc &__a=_Alloc())
Construct string as multiple characters.
_If_sv< _Tp, basic_string & > assign(const _Tp &__svt, size_type __pos, size_type __n=npos)
Set value from a range of characters in a string_view.
void shrink_to_fit() noexcept
A non-binding request to reduce capacity() to size().
basic_string & replace(iterator __i1, iterator __i2, const _CharT *__s, size_type __n)
Replace range of characters with C substring.
basic_string & assign(basic_string &&__str) noexcept(allocator_traits< _Alloc >::is_always_equal::value)
Set value to contents of another string.
void resize(size_type __n, _CharT __c)
Resizes the string to the specified number of characters.
void reserve()
Equivalent to shrink_to_fit().
const _CharT * data() const noexcept
Return const pointer to contents.
basic_string & operator=(_CharT __c)
Set value to string of length 1.
const_reference at(size_type __n) const
Provides access to the data contained in the string.
const_reference back() const noexcept
const_reverse_iterator rend() const noexcept
_If_sv< _Tp, basic_string & > insert(size_type __pos1, const _Tp &__svt, size_type __pos2, size_type __n=npos)
Insert a string_view.
const_iterator end() const noexcept
basic_string & operator+=(_CharT __c)
Append a character.
size_type find_last_of(_CharT __c, size_type __pos=npos) const noexcept
Find last position of a character.
_If_sv< _Tp, size_type > find_first_not_of(const _Tp &__svt, size_type __pos=0) const noexcept(is_same< _Tp, __sv_type >::value)
Find position of a character not in a string_view.
basic_string & append(const basic_string &__str)
Append a string to this string.
_CharT * data() noexcept
Return non-const pointer to contents.
const_iterator begin() const noexcept
_If_sv< _Tp, int > compare(size_type __pos1, size_type __n1, const _Tp &__svt, size_type __pos2, size_type __n2=npos) const noexcept(is_same< _Tp, __sv_type >::value)
Compare to a string_view.
const_reverse_iterator crend() const noexcept
void resize(size_type __n)
Resizes the string to the specified number of characters.
const_reverse_iterator rbegin() const noexcept
_If_sv< _Tp, basic_string & > replace(size_type __pos1, size_type __n1, const _Tp &__svt, size_type __pos2, size_type __n2=npos)
Replace range of characters with string_view.
_If_sv< _Tp, int > compare(size_type __pos, size_type __n, const _Tp &__svt) const noexcept(is_same< _Tp, __sv_type >::value)
Compare to a string_view.
basic_string & operator=(const basic_string &__str)
Assign the value of str to this string.
const_reference operator[](size_type __pos) const noexcept
Subscript access to the data contained in the string.
basic_string & operator=(basic_string &&__str) noexcept(/*conditional */)
Move assign the value of str to this string.
void clear() noexcept
size_type find_first_of(_CharT __c, size_type __pos=0) const noexcept
Find position of a character.
basic_string & replace(iterator __i1, iterator __i2, _InputIterator __k1, _InputIterator __k2)
Replace range of characters with range.
bool empty() const noexcept
basic_string & append(initializer_list< _CharT > __l)
Append an initializer_list of characters.
reference back()
static const size_type npos
Value returned by various member functions when they fail.
allocator_type get_allocator() const noexcept
Return copy of allocator used to construct this string.
basic_string & insert(size_type __pos, const _CharT *__s)
Insert a C string.
const_iterator cbegin() const noexcept
basic_string & erase(size_type __pos=0, size_type __n=npos)
Remove characters.
basic_string & replace(iterator __i1, iterator __i2, const basic_string &__str)
Replace range of characters with string.
~basic_string() noexcept
Destroy the string instance.
size_type capacity() const noexcept
basic_string & operator+=(const _CharT *__s)
Append a C string.
basic_string() noexcept
Default constructor creates an empty string.
void insert(iterator __p, _InputIterator __beg, _InputIterator __end)
Insert a range of characters.
size_type find_first_of(const _CharT *__s, size_type __pos=0) const noexcept
Find position of a character of C string.
basic_string & replace(size_type __pos1, size_type __n1, const basic_string &__str, size_type __pos2, size_type __n2=npos)
Replace characters with value from another string.
size_type max_size() const noexcept
Returns the size() of the largest possible string.
reference operator[](size_type __pos)
Subscript access to the data contained in the string.
basic_string & insert(size_type __pos, size_type __n, _CharT __c)
Insert multiple characters.
basic_string(const _CharT *__s, const _Alloc &__a=_Alloc())
Construct string as copy of a C string.
_If_sv< _Tp, size_type > find_last_not_of(const _Tp &__svt, size_type __pos=npos) const noexcept(is_same< _Tp, __sv_type >::value)
Find last position of a character not in a string_view.
basic_string(const _CharT *__s, size_type __n, const _Alloc &__a=_Alloc())
Construct string initialized by a character array.
basic_string & assign(const basic_string &__str, size_type __pos, size_type __n=npos)
Set value to a substring of a string.
basic_string & append(const _CharT *__s)
Append a C string.
size_type find_first_not_of(const _CharT *__s, size_type __pos=0) const noexcept
Find position of a character not in C string.
reference at(size_type __n)
Provides access to the data contained in the string.
_If_sv< _Tp, size_type > find_first_of(const _Tp &__svt, size_type __pos=0) const noexcept(is_same< _Tp, __sv_type >::value)
Find position of a character of a string_view.
iterator insert(iterator __p, _CharT __c)
Insert one character.
Basis for explicit traits specializations.
Definition: char_traits.h:311
Uniform interface to all pointer-like types.
Definition: ptr_traits.h:84
Marking input iterators.
Forward iterators support a superset of input iterator operations.
Common iterator class.
Uniform interface to C++98 and C++11 allocators.