libstdc++
sstream
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1 // String based streams -*- C++ -*-
2 
3 // Copyright (C) 1997-2022 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 include/sstream
26  * This is a Standard C++ Library header.
27  */
28 
29 //
30 // ISO C++ 14882: 27.7 String-based streams
31 //
32 
33 #ifndef _GLIBCXX_SSTREAM
34 #define _GLIBCXX_SSTREAM 1
35 
36 #pragma GCC system_header
37 
38 #include <istream>
39 #include <ostream>
40 #include <bits/alloc_traits.h> // allocator_traits, __allocator_like
41 
42 #if __cplusplus > 201703L && _GLIBCXX_USE_CXX11_ABI
43 # define _GLIBCXX_LVAL_REF_QUAL &
44 #else
45 # define _GLIBCXX_LVAL_REF_QUAL
46 #endif
47 
48 namespace std _GLIBCXX_VISIBILITY(default)
49 {
50 _GLIBCXX_BEGIN_NAMESPACE_VERSION
51 _GLIBCXX_BEGIN_NAMESPACE_CXX11
52 
53  // [27.7.1] template class basic_stringbuf
54  /**
55  * @brief The actual work of input and output (for std::string).
56  * @ingroup io
57  *
58  * @tparam _CharT Type of character stream.
59  * @tparam _Traits Traits for character type, defaults to
60  * char_traits<_CharT>.
61  * @tparam _Alloc Allocator type, defaults to allocator<_CharT>.
62  *
63  * This class associates either or both of its input and output sequences
64  * with a sequence of characters, which can be initialized from, or made
65  * available as, a @c std::basic_string. (Paraphrased from [27.7.1]/1.)
66  *
67  * For this class, open modes (of type @c ios_base::openmode) have
68  * @c in set if the input sequence can be read, and @c out set if the
69  * output sequence can be written.
70  */
71  template<typename _CharT, typename _Traits, typename _Alloc>
72  class basic_stringbuf : public basic_streambuf<_CharT, _Traits>
73  {
74  struct __xfer_bufptrs;
75 
76 #if __cplusplus >= 201103L
77  using allocator_traits = std::allocator_traits<_Alloc>;
78  using _Noexcept_swap
79  = __or_<typename allocator_traits::propagate_on_container_swap,
80  typename allocator_traits::is_always_equal>;
81 #endif
82 
83  public:
84  // Types:
85  typedef _CharT char_type;
86  typedef _Traits traits_type;
87  // _GLIBCXX_RESOLVE_LIB_DEFECTS
88  // 251. basic_stringbuf missing allocator_type
89  typedef _Alloc allocator_type;
90  typedef typename traits_type::int_type int_type;
91  typedef typename traits_type::pos_type pos_type;
92  typedef typename traits_type::off_type off_type;
93 
94  typedef basic_streambuf<char_type, traits_type> __streambuf_type;
95  typedef basic_string<char_type, _Traits, _Alloc> __string_type;
96  typedef typename __string_type::size_type __size_type;
97 
98  protected:
99  /// Place to stash in || out || in | out settings for current stringbuf.
100  ios_base::openmode _M_mode;
101 
102  // Data Members:
103  __string_type _M_string;
104 
105  public:
106  // Constructors:
107 
108  /**
109  * @brief Starts with an empty string buffer.
110  *
111  * The default constructor initializes the parent class using its
112  * own default ctor.
113  */
114  basic_stringbuf()
115  : __streambuf_type(), _M_mode(ios_base::in | ios_base::out), _M_string()
116  { }
117 
118  /**
119  * @brief Starts with an empty string buffer.
120  * @param __mode Whether the buffer can read, or write, or both.
121  *
122  * The default constructor initializes the parent class using its
123  * own default ctor.
124  */
125  explicit
126  basic_stringbuf(ios_base::openmode __mode)
127  : __streambuf_type(), _M_mode(__mode), _M_string()
128  { }
129 
130  /**
131  * @brief Starts with an existing string buffer.
132  * @param __str A string to copy as a starting buffer.
133  * @param __mode Whether the buffer can read, or write, or both.
134  *
135  * This constructor initializes the parent class using its
136  * own default ctor.
137  */
138  explicit
139  basic_stringbuf(const __string_type& __str,
140  ios_base::openmode __mode = ios_base::in | ios_base::out)
141  : __streambuf_type(), _M_mode(),
142  _M_string(__str.data(), __str.size(), __str.get_allocator())
143  { _M_stringbuf_init(__mode); }
144 
145 #if __cplusplus >= 201103L
146  basic_stringbuf(const basic_stringbuf&) = delete;
147 
148  basic_stringbuf(basic_stringbuf&& __rhs)
149  : basic_stringbuf(std::move(__rhs), __xfer_bufptrs(__rhs, this))
150  { __rhs._M_sync(const_cast<char_type*>(__rhs._M_string.data()), 0, 0); }
151 
152 #if __cplusplus > 201703L && _GLIBCXX_USE_CXX11_ABI
153  explicit
154  basic_stringbuf(const allocator_type& __a)
155  : basic_stringbuf(ios_base::in | std::ios_base::out, __a)
156  { }
157 
158  basic_stringbuf(ios_base::openmode __mode,
159  const allocator_type& __a)
160  : __streambuf_type(), _M_mode(__mode), _M_string(__a)
161  { }
162 
163  explicit
164  basic_stringbuf(__string_type&& __s,
165  ios_base::openmode __mode = ios_base::in
166  | ios_base::out)
167  : __streambuf_type(), _M_mode(__mode), _M_string(std::move(__s))
168  { _M_stringbuf_init(__mode); }
169 
170  template<typename _SAlloc>
171  basic_stringbuf(const basic_string<_CharT, _Traits, _SAlloc>& __s,
172  const allocator_type& __a)
173  : basic_stringbuf(__s, ios_base::in | std::ios_base::out, __a)
174  { }
175 
176  template<typename _SAlloc>
177  basic_stringbuf(const basic_string<_CharT, _Traits, _SAlloc>& __s,
178  ios_base::openmode __mode,
179  const allocator_type& __a)
180  : __streambuf_type(), _M_mode(__mode),
181  _M_string(__s.data(), __s.size(), __a)
182  { _M_stringbuf_init(__mode); }
183 
184  template<typename _SAlloc>
185  explicit
186  basic_stringbuf(const basic_string<_CharT, _Traits, _SAlloc>& __s,
187  ios_base::openmode __mode = ios_base::in
188  | ios_base::out)
189  : basic_stringbuf(__s, __mode, allocator_type{})
190  { }
191 
192  basic_stringbuf(basic_stringbuf&& __rhs, const allocator_type& __a)
193  : basic_stringbuf(std::move(__rhs), __a, __xfer_bufptrs(__rhs, this))
194  { __rhs._M_sync(const_cast<char_type*>(__rhs._M_string.data()), 0, 0); }
195 
196  allocator_type get_allocator() const noexcept
197  { return _M_string.get_allocator(); }
198 #endif // C++20
199 
200  // 27.8.2.2 Assign and swap:
201 
202  basic_stringbuf&
203  operator=(const basic_stringbuf&) = delete;
204 
205  basic_stringbuf&
206  operator=(basic_stringbuf&& __rhs)
207  {
208  __xfer_bufptrs __st{__rhs, this};
209  const __streambuf_type& __base = __rhs;
210  __streambuf_type::operator=(__base);
211  this->pubimbue(__rhs.getloc());
212  _M_mode = __rhs._M_mode;
213  _M_string = std::move(__rhs._M_string);
214  __rhs._M_sync(const_cast<char_type*>(__rhs._M_string.data()), 0, 0);
215  return *this;
216  }
217 
218  void
219  swap(basic_stringbuf& __rhs) noexcept(_Noexcept_swap::value)
220  {
221  __xfer_bufptrs __l_st{*this, std::__addressof(__rhs)};
222  __xfer_bufptrs __r_st{__rhs, this};
223  __streambuf_type& __base = __rhs;
224  __streambuf_type::swap(__base);
225  __rhs.pubimbue(this->pubimbue(__rhs.getloc()));
226  std::swap(_M_mode, __rhs._M_mode);
227  std::swap(_M_string, __rhs._M_string); // XXX not exception safe
228  }
229 #endif // C++11
230 
231  // Getters and setters:
232 
233  /**
234  * @brief Copying out the string buffer.
235  * @return A copy of one of the underlying sequences.
236  *
237  * <em>If the buffer is only created in input mode, the underlying
238  * character sequence is equal to the input sequence; otherwise, it
239  * is equal to the output sequence.</em> [27.7.1.2]/1
240  */
241  __string_type
242  str() const _GLIBCXX_LVAL_REF_QUAL
243  {
244  __string_type __ret(_M_string.get_allocator());
245  if (char_type* __hi = _M_high_mark())
246  __ret.assign(this->pbase(), __hi);
247  else
248  __ret = _M_string;
249  return __ret;
250  }
251 
252 #if __cplusplus > 201703L && _GLIBCXX_USE_CXX11_ABI
253 #if __cpp_concepts
254  template<__allocator_like _SAlloc>
255  basic_string<_CharT, _Traits, _SAlloc>
256  str(const _SAlloc& __sa) const
257  {
258  auto __sv = view();
259  return { __sv.data(), __sv.size(), __sa };
260  }
261 #endif
262 
263  __string_type
264  str() &&
265  {
266  if (char_type* __hi = _M_high_mark())
267  {
268  // Set length to end of character sequence and add null terminator.
269  _M_string._M_set_length(_M_high_mark() - this->pbase());
270  }
271  auto __str = std::move(_M_string);
272  _M_string.clear();
273  _M_sync(_M_string.data(), 0, 0);
274  return __str;
275  }
276 
277  basic_string_view<char_type, traits_type>
278  view() const noexcept
279  {
280  if (char_type* __hi = _M_high_mark())
281  return { this->pbase(), __hi };
282  else
283  return _M_string;
284  }
285 #endif // C++20
286 
287  /**
288  * @brief Setting a new buffer.
289  * @param __s The string to use as a new sequence.
290  *
291  * Deallocates any previous stored sequence, then copies @a s to
292  * use as a new one.
293  */
294  void
295  str(const __string_type& __s)
296  {
297  // Cannot use _M_string = __s, since v3 strings are COW
298  // (not always true now but assign() always works).
299  _M_string.assign(__s.data(), __s.size());
300  _M_stringbuf_init(_M_mode);
301  }
302 
303 #if __cplusplus > 201703L && _GLIBCXX_USE_CXX11_ABI
304 #if __cpp_concepts
305  template<__allocator_like _SAlloc>
306  requires (!is_same_v<_SAlloc, _Alloc>)
307  void
308  str(const basic_string<_CharT, _Traits, _SAlloc>& __s)
309  {
310  _M_string.assign(__s.data(), __s.size());
311  _M_stringbuf_init(_M_mode);
312  }
313 #endif
314 
315  void
316  str(__string_type&& __s)
317  {
318  _M_string = std::move(__s);
319  _M_stringbuf_init(_M_mode);
320  }
321 #endif
322 
323  protected:
324  // Common initialization code goes here.
325  void
326  _M_stringbuf_init(ios_base::openmode __mode)
327  {
328  _M_mode = __mode;
329  __size_type __len = 0;
330  if (_M_mode & (ios_base::ate | ios_base::app))
331  __len = _M_string.size();
332  _M_sync(const_cast<char_type*>(_M_string.data()), 0, __len);
333  }
334 
335  virtual streamsize
336  showmanyc()
337  {
338  streamsize __ret = -1;
339  if (_M_mode & ios_base::in)
340  {
341  _M_update_egptr();
342  __ret = this->egptr() - this->gptr();
343  }
344  return __ret;
345  }
346 
347  virtual int_type
348  underflow();
349 
350  virtual int_type
351  pbackfail(int_type __c = traits_type::eof());
352 
353  virtual int_type
354  overflow(int_type __c = traits_type::eof());
355 
356  /**
357  * @brief Manipulates the buffer.
358  * @param __s Pointer to a buffer area.
359  * @param __n Size of @a __s.
360  * @return @c this
361  *
362  * If no buffer has already been created, and both @a __s and @a __n are
363  * non-zero, then @c __s is used as a buffer; see
364  * https://gcc.gnu.org/onlinedocs/libstdc++/manual/streambufs.html#io.streambuf.buffering
365  * for more.
366  */
367  virtual __streambuf_type*
368  setbuf(char_type* __s, streamsize __n)
369  {
370  if (__s && __n >= 0)
371  {
372  // This is implementation-defined behavior, and assumes
373  // that an external char_type array of length __n exists
374  // and has been pre-allocated. If this is not the case,
375  // things will quickly blow up.
376 
377  // Step 1: Destroy the current internal array.
378  _M_string.clear();
379 
380  // Step 2: Use the external array.
381  _M_sync(__s, __n, 0);
382  }
383  return this;
384  }
385 
386  virtual pos_type
387  seekoff(off_type __off, ios_base::seekdir __way,
388  ios_base::openmode __mode = ios_base::in | ios_base::out);
389 
390  virtual pos_type
391  seekpos(pos_type __sp,
392  ios_base::openmode __mode = ios_base::in | ios_base::out);
393 
394  // Internal function for correctly updating the internal buffer
395  // for a particular _M_string, due to initialization or re-sizing
396  // of an existing _M_string.
397  void
398  _M_sync(char_type* __base, __size_type __i, __size_type __o);
399 
400  // Internal function for correctly updating egptr() to the actual
401  // string end.
402  void
403  _M_update_egptr()
404  {
405  if (char_type* __pptr = this->pptr())
406  {
407  char_type* __egptr = this->egptr();
408  if (!__egptr || __pptr > __egptr)
409  {
410  if (_M_mode & ios_base::in)
411  this->setg(this->eback(), this->gptr(), __pptr);
412  else
413  this->setg(__pptr, __pptr, __pptr);
414  }
415  }
416  }
417 
418  // Works around the issue with pbump, part of the protected
419  // interface of basic_streambuf, taking just an int.
420  void
421  _M_pbump(char_type* __pbeg, char_type* __pend, off_type __off);
422 
423  private:
424  // Return a pointer to the end of the underlying character sequence.
425  // This might not be the same character as _M_string.end() because
426  // basic_stringbuf::overflow might have written to unused capacity
427  // in _M_string without updating its length.
428  __attribute__((__always_inline__))
429  char_type*
430  _M_high_mark() const _GLIBCXX_NOEXCEPT
431  {
432  if (char_type* __pptr = this->pptr())
433  {
434  char_type* __egptr = this->egptr();
435  if (!__egptr || __pptr > __egptr)
436  return __pptr; // Underlying sequence is [pbase, pptr).
437  else
438  return __egptr; // Underlying sequence is [pbase, egptr).
439  }
440  return 0; // Underlying character sequence is just _M_string.
441  }
442 
443 #if __cplusplus >= 201103L
444 #if _GLIBCXX_USE_CXX11_ABI
445  // This type captures the state of the gptr / pptr pointers as offsets
446  // so they can be restored in another object after moving the string.
447  struct __xfer_bufptrs
448  {
449  __xfer_bufptrs(const basic_stringbuf& __from, basic_stringbuf* __to)
450  : _M_to{__to}, _M_goff{-1, -1, -1}, _M_poff{-1, -1, -1}
451  {
452  const _CharT* const __str = __from._M_string.data();
453  const _CharT* __end = nullptr;
454  if (__from.eback())
455  {
456  _M_goff[0] = __from.eback() - __str;
457  _M_goff[1] = __from.gptr() - __str;
458  _M_goff[2] = __from.egptr() - __str;
459  __end = __from.egptr();
460  }
461  if (__from.pbase())
462  {
463  _M_poff[0] = __from.pbase() - __str;
464  _M_poff[1] = __from.pptr() - __from.pbase();
465  _M_poff[2] = __from.epptr() - __str;
466  if (!__end || __from.pptr() > __end)
467  __end = __from.pptr();
468  }
469 
470  // Set _M_string length to the greater of the get and put areas.
471  if (__end)
472  {
473  // The const_cast avoids changing this constructor's signature,
474  // because it is exported from the dynamic library.
475  auto& __mut_from = const_cast<basic_stringbuf&>(__from);
476  __mut_from._M_string._M_length(__end - __str);
477  }
478  }
479 
480  ~__xfer_bufptrs()
481  {
482  char_type* __str = const_cast<char_type*>(_M_to->_M_string.data());
483  if (_M_goff[0] != -1)
484  _M_to->setg(__str+_M_goff[0], __str+_M_goff[1], __str+_M_goff[2]);
485  if (_M_poff[0] != -1)
486  _M_to->_M_pbump(__str+_M_poff[0], __str+_M_poff[2], _M_poff[1]);
487  }
488 
489  basic_stringbuf* _M_to;
490  off_type _M_goff[3];
491  off_type _M_poff[3];
492  };
493 #else
494  // This type does nothing when using Copy-On-Write strings.
495  struct __xfer_bufptrs
496  {
497  __xfer_bufptrs(const basic_stringbuf&, basic_stringbuf*) { }
498  };
499 #endif
500 
501  // The move constructor initializes an __xfer_bufptrs temporary then
502  // delegates to this constructor to performs moves during its lifetime.
503  basic_stringbuf(basic_stringbuf&& __rhs, __xfer_bufptrs&&)
504  : __streambuf_type(static_cast<const __streambuf_type&>(__rhs)),
505  _M_mode(__rhs._M_mode), _M_string(std::move(__rhs._M_string))
506  { }
507 
508 #if __cplusplus > 201703L && _GLIBCXX_USE_CXX11_ABI
509  // The move constructor initializes an __xfer_bufptrs temporary then
510  // delegates to this constructor to performs moves during its lifetime.
511  basic_stringbuf(basic_stringbuf&& __rhs, const allocator_type& __a,
512  __xfer_bufptrs&&)
513  : __streambuf_type(static_cast<const __streambuf_type&>(__rhs)),
514  _M_mode(__rhs._M_mode), _M_string(std::move(__rhs._M_string), __a)
515  { }
516 #endif
517 #endif // C++11
518  };
519 
520 
521  // [27.7.2] Template class basic_istringstream
522  /**
523  * @brief Controlling input for std::string.
524  * @ingroup io
525  *
526  * @tparam _CharT Type of character stream.
527  * @tparam _Traits Traits for character type, defaults to
528  * char_traits<_CharT>.
529  * @tparam _Alloc Allocator type, defaults to allocator<_CharT>.
530  *
531  * This class supports reading from objects of type std::basic_string,
532  * using the inherited functions from std::basic_istream. To control
533  * the associated sequence, an instance of std::basic_stringbuf is used,
534  * which this page refers to as @c sb.
535  */
536  template<typename _CharT, typename _Traits, typename _Alloc>
537  class basic_istringstream : public basic_istream<_CharT, _Traits>
538  {
539  public:
540  // Types:
541  typedef _CharT char_type;
542  typedef _Traits traits_type;
543  // _GLIBCXX_RESOLVE_LIB_DEFECTS
544  // 251. basic_stringbuf missing allocator_type
545  typedef _Alloc allocator_type;
546  typedef typename traits_type::int_type int_type;
547  typedef typename traits_type::pos_type pos_type;
548  typedef typename traits_type::off_type off_type;
549 
550  // Non-standard types:
551  typedef basic_string<_CharT, _Traits, _Alloc> __string_type;
552  typedef basic_stringbuf<_CharT, _Traits, _Alloc> __stringbuf_type;
553  typedef basic_istream<char_type, traits_type> __istream_type;
554 
555  private:
556  __stringbuf_type _M_stringbuf;
557 
558  public:
559  // Constructors:
560 
561  /**
562  * @brief Default constructor starts with an empty string buffer.
563  *
564  * Initializes @c sb using @c in, and passes @c &sb to the base
565  * class initializer. Does not allocate any buffer.
566  *
567  * That's a lie. We initialize the base class with NULL, because the
568  * string class does its own memory management.
569  */
570  basic_istringstream()
571  : __istream_type(), _M_stringbuf(ios_base::in)
572  { this->init(&_M_stringbuf); }
573 
574  /**
575  * @brief Starts with an empty string buffer.
576  * @param __mode Whether the buffer can read, or write, or both.
577  *
578  * @c ios_base::in is automatically included in @a __mode.
579  *
580  * Initializes @c sb using @c __mode|in, and passes @c &sb to the base
581  * class initializer. Does not allocate any buffer.
582  *
583  * That's a lie. We initialize the base class with NULL, because the
584  * string class does its own memory management.
585  */
586  explicit
587  basic_istringstream(ios_base::openmode __mode)
588  : __istream_type(), _M_stringbuf(__mode | ios_base::in)
589  { this->init(&_M_stringbuf); }
590 
591  /**
592  * @brief Starts with an existing string buffer.
593  * @param __str A string to copy as a starting buffer.
594  * @param __mode Whether the buffer can read, or write, or both.
595  *
596  * @c ios_base::in is automatically included in @a mode.
597  *
598  * Initializes @c sb using @a str and @c mode|in, and passes @c &sb
599  * to the base class initializer.
600  *
601  * That's a lie. We initialize the base class with NULL, because the
602  * string class does its own memory management.
603  */
604  explicit
605  basic_istringstream(const __string_type& __str,
606  ios_base::openmode __mode = ios_base::in)
607  : __istream_type(), _M_stringbuf(__str, __mode | ios_base::in)
608  { this->init(&_M_stringbuf); }
609 
610  /**
611  * @brief The destructor does nothing.
612  *
613  * The buffer is deallocated by the stringbuf object, not the
614  * formatting stream.
615  */
616  ~basic_istringstream()
617  { }
618 
619 #if __cplusplus >= 201103L
620  basic_istringstream(const basic_istringstream&) = delete;
621 
622  basic_istringstream(basic_istringstream&& __rhs)
623  : __istream_type(std::move(__rhs)),
624  _M_stringbuf(std::move(__rhs._M_stringbuf))
625  { __istream_type::set_rdbuf(&_M_stringbuf); }
626 
627 #if __cplusplus > 201703L && _GLIBCXX_USE_CXX11_ABI
628  basic_istringstream(ios_base::openmode __mode, const allocator_type& __a)
629  : __istream_type(), _M_stringbuf(__mode | ios_base::in, __a)
630  { this->init(std::__addressof(_M_stringbuf)); }
631 
632  explicit
633  basic_istringstream(__string_type&& __str,
634  ios_base::openmode __mode = ios_base::in)
635  : __istream_type(), _M_stringbuf(std::move(__str), __mode | ios_base::in)
636  { this->init(std::__addressof(_M_stringbuf)); }
637 
638  template<typename _SAlloc>
639  basic_istringstream(const basic_string<_CharT, _Traits, _SAlloc>& __str,
640  const allocator_type& __a)
641  : basic_istringstream(__str, ios_base::in, __a)
642  { }
643 
644  template<typename _SAlloc>
645  basic_istringstream(const basic_string<_CharT, _Traits, _SAlloc>& __str,
646  ios_base::openmode __mode,
647  const allocator_type& __a)
648  : __istream_type(), _M_stringbuf(__str, __mode | ios_base::in, __a)
649  { this->init(std::__addressof(_M_stringbuf)); }
650 
651  template<typename _SAlloc>
652  explicit
653  basic_istringstream(const basic_string<_CharT, _Traits, _SAlloc>& __str,
654  ios_base::openmode __mode = ios_base::in)
655  : basic_istringstream(__str, __mode, allocator_type())
656  { }
657 #endif // C++20
658 
659  // 27.8.3.2 Assign and swap:
660 
661  basic_istringstream&
662  operator=(const basic_istringstream&) = delete;
663 
664  basic_istringstream&
665  operator=(basic_istringstream&& __rhs)
666  {
667  __istream_type::operator=(std::move(__rhs));
668  _M_stringbuf = std::move(__rhs._M_stringbuf);
669  return *this;
670  }
671 
672  void
673  swap(basic_istringstream& __rhs)
674  {
675  __istream_type::swap(__rhs);
676  _M_stringbuf.swap(__rhs._M_stringbuf);
677  }
678 #endif // C++11
679 
680  // Members:
681  /**
682  * @brief Accessing the underlying buffer.
683  * @return The current basic_stringbuf buffer.
684  *
685  * This hides both signatures of std::basic_ios::rdbuf().
686  */
687  __stringbuf_type*
688  rdbuf() const
689  { return const_cast<__stringbuf_type*>(&_M_stringbuf); }
690 
691  /**
692  * @brief Copying out the string buffer.
693  * @return @c rdbuf()->str()
694  */
695  __string_type
696  str() const _GLIBCXX_LVAL_REF_QUAL
697  { return _M_stringbuf.str(); }
698 
699 #if __cplusplus > 201703L && _GLIBCXX_USE_CXX11_ABI
700 #if __cpp_concepts
701  template<__allocator_like _SAlloc>
702  basic_string<_CharT, _Traits, _SAlloc>
703  str(const _SAlloc& __sa) const
704  { return _M_stringbuf.str(__sa); }
705 #endif
706 
707  __string_type
708  str() &&
709  { return std::move(_M_stringbuf).str(); }
710 
711  basic_string_view<char_type, traits_type>
712  view() const noexcept
713  { return _M_stringbuf.view(); }
714 #endif
715 
716  /**
717  * @brief Setting a new buffer.
718  * @param __s The string to use as a new sequence.
719  *
720  * Calls @c rdbuf()->str(s).
721  */
722  void
723  str(const __string_type& __s)
724  { _M_stringbuf.str(__s); }
725 
726 #if __cplusplus > 201703L && _GLIBCXX_USE_CXX11_ABI
727 #if __cpp_concepts
728  template<__allocator_like _SAlloc>
729  requires (!is_same_v<_SAlloc, _Alloc>)
730  void
731  str(const basic_string<_CharT, _Traits, _SAlloc>& __s)
732  { _M_stringbuf.str(__s); }
733 #endif
734 
735  void
736  str(__string_type&& __s)
737  { _M_stringbuf.str(std::move(__s)); }
738 #endif
739  };
740 
741 
742  // [27.7.3] Template class basic_ostringstream
743  /**
744  * @brief Controlling output for std::string.
745  * @ingroup io
746  *
747  * @tparam _CharT Type of character stream.
748  * @tparam _Traits Traits for character type, defaults to
749  * char_traits<_CharT>.
750  * @tparam _Alloc Allocator type, defaults to allocator<_CharT>.
751  *
752  * This class supports writing to objects of type std::basic_string,
753  * using the inherited functions from std::basic_ostream. To control
754  * the associated sequence, an instance of std::basic_stringbuf is used,
755  * which this page refers to as @c sb.
756  */
757  template <typename _CharT, typename _Traits, typename _Alloc>
758  class basic_ostringstream : public basic_ostream<_CharT, _Traits>
759  {
760  public:
761  // Types:
762  typedef _CharT char_type;
763  typedef _Traits traits_type;
764  // _GLIBCXX_RESOLVE_LIB_DEFECTS
765  // 251. basic_stringbuf missing allocator_type
766  typedef _Alloc allocator_type;
767  typedef typename traits_type::int_type int_type;
768  typedef typename traits_type::pos_type pos_type;
769  typedef typename traits_type::off_type off_type;
770 
771  // Non-standard types:
772  typedef basic_string<_CharT, _Traits, _Alloc> __string_type;
773  typedef basic_stringbuf<_CharT, _Traits, _Alloc> __stringbuf_type;
774  typedef basic_ostream<char_type, traits_type> __ostream_type;
775 
776  private:
777  __stringbuf_type _M_stringbuf;
778 
779  public:
780  // Constructors/destructor:
781 
782  /**
783  * @brief Default constructor starts with an empty string buffer.
784  *
785  * Initializes @c sb using @c mode|out, and passes @c &sb to the base
786  * class initializer. Does not allocate any buffer.
787  *
788  * That's a lie. We initialize the base class with NULL, because the
789  * string class does its own memory management.
790  */
791  basic_ostringstream()
792  : __ostream_type(), _M_stringbuf(ios_base::out)
793  { this->init(&_M_stringbuf); }
794 
795  /**
796  * @brief Starts with an empty string buffer.
797  * @param __mode Whether the buffer can read, or write, or both.
798  *
799  * @c ios_base::out is automatically included in @a mode.
800  *
801  * Initializes @c sb using @c mode|out, and passes @c &sb to the base
802  * class initializer. Does not allocate any buffer.
803  *
804  * That's a lie. We initialize the base class with NULL, because the
805  * string class does its own memory management.
806  */
807  explicit
808  basic_ostringstream(ios_base::openmode __mode)
809  : __ostream_type(), _M_stringbuf(__mode | ios_base::out)
810  { this->init(&_M_stringbuf); }
811 
812  /**
813  * @brief Starts with an existing string buffer.
814  * @param __str A string to copy as a starting buffer.
815  * @param __mode Whether the buffer can read, or write, or both.
816  *
817  * @c ios_base::out is automatically included in @a mode.
818  *
819  * Initializes @c sb using @a str and @c mode|out, and passes @c &sb
820  * to the base class initializer.
821  *
822  * That's a lie. We initialize the base class with NULL, because the
823  * string class does its own memory management.
824  */
825  explicit
826  basic_ostringstream(const __string_type& __str,
827  ios_base::openmode __mode = ios_base::out)
828  : __ostream_type(), _M_stringbuf(__str, __mode | ios_base::out)
829  { this->init(&_M_stringbuf); }
830 
831  /**
832  * @brief The destructor does nothing.
833  *
834  * The buffer is deallocated by the stringbuf object, not the
835  * formatting stream.
836  */
837  ~basic_ostringstream()
838  { }
839 
840 #if __cplusplus >= 201103L
841  basic_ostringstream(const basic_ostringstream&) = delete;
842 
843  basic_ostringstream(basic_ostringstream&& __rhs)
844  : __ostream_type(std::move(__rhs)),
845  _M_stringbuf(std::move(__rhs._M_stringbuf))
846  { __ostream_type::set_rdbuf(&_M_stringbuf); }
847 
848 #if __cplusplus > 201703L && _GLIBCXX_USE_CXX11_ABI
849  basic_ostringstream(ios_base::openmode __mode, const allocator_type& __a)
850  : __ostream_type(), _M_stringbuf(__mode | ios_base::out, __a)
851  { this->init(std::__addressof(_M_stringbuf)); }
852 
853  explicit
854  basic_ostringstream(__string_type&& __str,
855  ios_base::openmode __mode = ios_base::out)
856  : __ostream_type(), _M_stringbuf(std::move(__str), __mode | ios_base::out)
857  { this->init(std::__addressof(_M_stringbuf)); }
858 
859  template<typename _SAlloc>
860  basic_ostringstream(const basic_string<_CharT, _Traits, _SAlloc>& __str,
861  const allocator_type& __a)
862  : basic_ostringstream(__str, ios_base::out, __a)
863  { }
864 
865  template<typename _SAlloc>
866  basic_ostringstream(const basic_string<_CharT, _Traits, _SAlloc>& __str,
867  ios_base::openmode __mode,
868  const allocator_type& __a)
869  : __ostream_type(), _M_stringbuf(__str, __mode | ios_base::out, __a)
870  { this->init(std::__addressof(_M_stringbuf)); }
871 
872  template<typename _SAlloc>
873  explicit
874  basic_ostringstream(const basic_string<_CharT, _Traits, _SAlloc>& __str,
875  ios_base::openmode __mode = ios_base::out)
876  : basic_ostringstream(__str, __mode, allocator_type())
877  { }
878 #endif // C++20
879 
880  // 27.8.3.2 Assign and swap:
881 
882  basic_ostringstream&
883  operator=(const basic_ostringstream&) = delete;
884 
885  basic_ostringstream&
886  operator=(basic_ostringstream&& __rhs)
887  {
888  __ostream_type::operator=(std::move(__rhs));
889  _M_stringbuf = std::move(__rhs._M_stringbuf);
890  return *this;
891  }
892 
893  void
894  swap(basic_ostringstream& __rhs)
895  {
896  __ostream_type::swap(__rhs);
897  _M_stringbuf.swap(__rhs._M_stringbuf);
898  }
899 #endif // C++11
900 
901  // Members:
902  /**
903  * @brief Accessing the underlying buffer.
904  * @return The current basic_stringbuf buffer.
905  *
906  * This hides both signatures of std::basic_ios::rdbuf().
907  */
908  __stringbuf_type*
909  rdbuf() const
910  { return const_cast<__stringbuf_type*>(&_M_stringbuf); }
911 
912  /**
913  * @brief Copying out the string buffer.
914  * @return @c rdbuf()->str()
915  */
916  __string_type
917  str() const _GLIBCXX_LVAL_REF_QUAL
918  { return _M_stringbuf.str(); }
919 
920 #if __cplusplus > 201703L && _GLIBCXX_USE_CXX11_ABI
921 #if __cpp_concepts
922  template<__allocator_like _SAlloc>
923  basic_string<_CharT, _Traits, _SAlloc>
924  str(const _SAlloc& __sa) const
925  { return _M_stringbuf.str(__sa); }
926 #endif
927 
928  __string_type
929  str() &&
930  { return std::move(_M_stringbuf).str(); }
931 
932  basic_string_view<char_type, traits_type>
933  view() const noexcept
934  { return _M_stringbuf.view(); }
935 #endif
936 
937  /**
938  * @brief Setting a new buffer.
939  * @param __s The string to use as a new sequence.
940  *
941  * Calls @c rdbuf()->str(s).
942  */
943  void
944  str(const __string_type& __s)
945  { _M_stringbuf.str(__s); }
946 
947 #if __cplusplus > 201703L && _GLIBCXX_USE_CXX11_ABI
948 #if __cpp_concepts
949  template<__allocator_like _SAlloc>
950  requires (!is_same_v<_SAlloc, _Alloc>)
951  void
952  str(const basic_string<_CharT, _Traits, _SAlloc>& __s)
953  { _M_stringbuf.str(__s); }
954 #endif
955 
956  void
957  str(__string_type&& __s)
958  { _M_stringbuf.str(std::move(__s)); }
959 #endif
960  };
961 
962 
963  // [27.7.4] Template class basic_stringstream
964  /**
965  * @brief Controlling input and output for std::string.
966  * @ingroup io
967  *
968  * @tparam _CharT Type of character stream.
969  * @tparam _Traits Traits for character type, defaults to
970  * char_traits<_CharT>.
971  * @tparam _Alloc Allocator type, defaults to allocator<_CharT>.
972  *
973  * This class supports reading from and writing to objects of type
974  * std::basic_string, using the inherited functions from
975  * std::basic_iostream. To control the associated sequence, an instance
976  * of std::basic_stringbuf is used, which this page refers to as @c sb.
977  */
978  template <typename _CharT, typename _Traits, typename _Alloc>
979  class basic_stringstream : public basic_iostream<_CharT, _Traits>
980  {
981  public:
982  // Types:
983  typedef _CharT char_type;
984  typedef _Traits traits_type;
985  // _GLIBCXX_RESOLVE_LIB_DEFECTS
986  // 251. basic_stringbuf missing allocator_type
987  typedef _Alloc allocator_type;
988  typedef typename traits_type::int_type int_type;
989  typedef typename traits_type::pos_type pos_type;
990  typedef typename traits_type::off_type off_type;
991 
992  // Non-standard Types:
993  typedef basic_string<_CharT, _Traits, _Alloc> __string_type;
994  typedef basic_stringbuf<_CharT, _Traits, _Alloc> __stringbuf_type;
995  typedef basic_iostream<char_type, traits_type> __iostream_type;
996 
997  private:
998  __stringbuf_type _M_stringbuf;
999 
1000  public:
1001  // Constructors/destructors
1002 
1003  /**
1004  * @brief Default constructor starts with an empty string buffer.
1005  *
1006  * Initializes @c sb using the mode @c in|out, and passes @c &sb
1007  * to the base class initializer. Does not allocate any buffer.
1008  *
1009  * That's a lie. We initialize the base class with NULL, because the
1010  * string class does its own memory management.
1011  */
1012  basic_stringstream()
1013  : __iostream_type(), _M_stringbuf(ios_base::out | ios_base::in)
1014  { this->init(&_M_stringbuf); }
1015 
1016  /**
1017  * @brief Starts with an empty string buffer.
1018  * @param __m Whether the buffer can read, or write, or both.
1019  *
1020  * Initializes @c sb using the mode from @c __m, and passes @c &sb
1021  * to the base class initializer. Does not allocate any buffer.
1022  *
1023  * That's a lie. We initialize the base class with NULL, because the
1024  * string class does its own memory management.
1025  */
1026  explicit
1027  basic_stringstream(ios_base::openmode __m)
1028  : __iostream_type(), _M_stringbuf(__m)
1029  { this->init(&_M_stringbuf); }
1030 
1031  /**
1032  * @brief Starts with an existing string buffer.
1033  * @param __str A string to copy as a starting buffer.
1034  * @param __m Whether the buffer can read, or write, or both.
1035  *
1036  * Initializes @c sb using @a __str and @c __m, and passes @c &sb
1037  * to the base class initializer.
1038  *
1039  * That's a lie. We initialize the base class with NULL, because the
1040  * string class does its own memory management.
1041  */
1042  explicit
1043  basic_stringstream(const __string_type& __str,
1044  ios_base::openmode __m = ios_base::out | ios_base::in)
1045  : __iostream_type(), _M_stringbuf(__str, __m)
1046  { this->init(&_M_stringbuf); }
1047 
1048  /**
1049  * @brief The destructor does nothing.
1050  *
1051  * The buffer is deallocated by the stringbuf object, not the
1052  * formatting stream.
1053  */
1054  ~basic_stringstream()
1055  { }
1056 
1057 #if __cplusplus >= 201103L
1058  basic_stringstream(const basic_stringstream&) = delete;
1059 
1060  basic_stringstream(basic_stringstream&& __rhs)
1061  : __iostream_type(std::move(__rhs)),
1062  _M_stringbuf(std::move(__rhs._M_stringbuf))
1063  { __iostream_type::set_rdbuf(&_M_stringbuf); }
1064 
1065 #if __cplusplus > 201703L && _GLIBCXX_USE_CXX11_ABI
1066  basic_stringstream(ios_base::openmode __mode, const allocator_type& __a)
1067  : __iostream_type(), _M_stringbuf(__mode, __a)
1068  { this->init(&_M_stringbuf); }
1069 
1070  explicit
1071  basic_stringstream(__string_type&& __str,
1072  ios_base::openmode __mode = ios_base::in
1073  | ios_base::out)
1074  : __iostream_type(), _M_stringbuf(std::move(__str), __mode)
1075  { this->init(std::__addressof(_M_stringbuf)); }
1076 
1077  template<typename _SAlloc>
1078  basic_stringstream(const basic_string<_CharT, _Traits, _SAlloc>& __str,
1079  const allocator_type& __a)
1080  : basic_stringstream(__str, ios_base::in | ios_base::out, __a)
1081  { }
1082 
1083  template<typename _SAlloc>
1084  basic_stringstream(const basic_string<_CharT, _Traits, _SAlloc>& __str,
1085  ios_base::openmode __mode,
1086  const allocator_type& __a)
1087  : __iostream_type(), _M_stringbuf(__str, __mode, __a)
1088  { this->init(std::__addressof(_M_stringbuf)); }
1089 
1090  template<typename _SAlloc>
1091  explicit
1092  basic_stringstream(const basic_string<_CharT, _Traits, _SAlloc>& __str,
1093  ios_base::openmode __mode = ios_base::in
1094  | ios_base::out)
1095  : basic_stringstream(__str, __mode, allocator_type())
1096  { }
1097 #endif // C++20
1098 
1099  // 27.8.3.2 Assign and swap:
1100 
1101  basic_stringstream&
1102  operator=(const basic_stringstream&) = delete;
1103 
1104  basic_stringstream&
1105  operator=(basic_stringstream&& __rhs)
1106  {
1107  __iostream_type::operator=(std::move(__rhs));
1108  _M_stringbuf = std::move(__rhs._M_stringbuf);
1109  return *this;
1110  }
1111 
1112  void
1113  swap(basic_stringstream& __rhs)
1114  {
1115  __iostream_type::swap(__rhs);
1116  _M_stringbuf.swap(__rhs._M_stringbuf);
1117  }
1118 #endif // C++11
1119 
1120  // Members:
1121  /**
1122  * @brief Accessing the underlying buffer.
1123  * @return The current basic_stringbuf buffer.
1124  *
1125  * This hides both signatures of std::basic_ios::rdbuf().
1126  */
1127  __stringbuf_type*
1128  rdbuf() const
1129  { return const_cast<__stringbuf_type*>(&_M_stringbuf); }
1130 
1131  /**
1132  * @brief Copying out the string buffer.
1133  * @return @c rdbuf()->str()
1134  */
1135  __string_type
1136  str() const _GLIBCXX_LVAL_REF_QUAL
1137  { return _M_stringbuf.str(); }
1138 
1139 #if __cplusplus > 201703L && _GLIBCXX_USE_CXX11_ABI
1140 #if __cpp_concepts
1141  template<__allocator_like _SAlloc>
1142  basic_string<_CharT, _Traits, _SAlloc>
1143  str(const _SAlloc& __sa) const
1144  { return _M_stringbuf.str(__sa); }
1145 #endif
1146 
1147  __string_type
1148  str() &&
1149  { return std::move(_M_stringbuf).str(); }
1150 
1151  basic_string_view<char_type, traits_type>
1152  view() const noexcept
1153  { return _M_stringbuf.view(); }
1154 #endif
1155 
1156  /**
1157  * @brief Setting a new buffer.
1158  * @param __s The string to use as a new sequence.
1159  *
1160  * Calls @c rdbuf()->str(s).
1161  */
1162  void
1163  str(const __string_type& __s)
1164  { _M_stringbuf.str(__s); }
1165 
1166 #if __cplusplus > 201703L && _GLIBCXX_USE_CXX11_ABI
1167 #if __cpp_concepts
1168  template<__allocator_like _SAlloc>
1169  requires (!is_same_v<_SAlloc, _Alloc>)
1170  void
1171  str(const basic_string<_CharT, _Traits, _SAlloc>& __s)
1172  { _M_stringbuf.str(__s); }
1173 #endif
1174 
1175  void
1176  str(__string_type&& __s)
1177  { _M_stringbuf.str(std::move(__s)); }
1178 #endif
1179  };
1180 
1181 #if __cplusplus >= 201103L
1182  /// Swap specialization for stringbufs.
1183  template <class _CharT, class _Traits, class _Allocator>
1184  inline void
1185  swap(basic_stringbuf<_CharT, _Traits, _Allocator>& __x,
1186  basic_stringbuf<_CharT, _Traits, _Allocator>& __y)
1187  noexcept(noexcept(__x.swap(__y)))
1188  { __x.swap(__y); }
1189 
1190  /// Swap specialization for istringstreams.
1191  template <class _CharT, class _Traits, class _Allocator>
1192  inline void
1193  swap(basic_istringstream<_CharT, _Traits, _Allocator>& __x,
1194  basic_istringstream<_CharT, _Traits, _Allocator>& __y)
1195  { __x.swap(__y); }
1196 
1197  /// Swap specialization for ostringstreams.
1198  template <class _CharT, class _Traits, class _Allocator>
1199  inline void
1200  swap(basic_ostringstream<_CharT, _Traits, _Allocator>& __x,
1201  basic_ostringstream<_CharT, _Traits, _Allocator>& __y)
1202  { __x.swap(__y); }
1203 
1204  /// Swap specialization for stringstreams.
1205  template <class _CharT, class _Traits, class _Allocator>
1206  inline void
1207  swap(basic_stringstream<_CharT, _Traits, _Allocator>& __x,
1208  basic_stringstream<_CharT, _Traits, _Allocator>& __y)
1209  { __x.swap(__y); }
1210 #endif // C++11
1211 
1212 _GLIBCXX_END_NAMESPACE_CXX11
1213 _GLIBCXX_END_NAMESPACE_VERSION
1214 } // namespace
1215 
1216 #undef _GLIBCXX_LVAL_REF_QUAL
1217 
1218 #include <bits/sstream.tcc>
1219 
1220 #endif /* _GLIBCXX_SSTREAM */