libstdc++
sstream
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1 // String based streams -*- C++ -*-
2 
3 // Copyright (C) 1997-2024 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 <bits/requires_hosted.h> // iostream
39 
40 #include <istream>
41 #include <ostream>
42 #include <bits/alloc_traits.h> // allocator_traits, __allocator_like
43 
44 #if __cplusplus > 201703L && _GLIBCXX_USE_CXX11_ABI
45 # define _GLIBCXX_LVAL_REF_QUAL &
46 # define _GLIBCXX_SSTREAM_ALWAYS_INLINE
47 #else
48 # define _GLIBCXX_LVAL_REF_QUAL
49 // For symbols that are not exported from libstdc++.so for the COW string ABI.
50 # define _GLIBCXX_SSTREAM_ALWAYS_INLINE [[__gnu__::__always_inline__]]
51 #endif
52 
53 
54 
55 namespace std _GLIBCXX_VISIBILITY(default)
56 {
57 _GLIBCXX_BEGIN_NAMESPACE_VERSION
58 _GLIBCXX_BEGIN_NAMESPACE_CXX11
59 
60  // [27.7.1] template class basic_stringbuf
61  /**
62  * @brief The actual work of input and output (for std::string).
63  * @ingroup io
64  *
65  * @tparam _CharT Type of character stream.
66  * @tparam _Traits Traits for character type, defaults to
67  * char_traits<_CharT>.
68  * @tparam _Alloc Allocator type, defaults to allocator<_CharT>.
69  *
70  * This class associates either or both of its input and output sequences
71  * with a sequence of characters, which can be initialized from, or made
72  * available as, a @c std::basic_string. (Paraphrased from [27.7.1]/1.)
73  *
74  * For this class, open modes (of type @c ios_base::openmode) have
75  * @c in set if the input sequence can be read, and @c out set if the
76  * output sequence can be written.
77  */
78  template<typename _CharT, typename _Traits, typename _Alloc>
79  class basic_stringbuf : public basic_streambuf<_CharT, _Traits>
80  {
81  struct __xfer_bufptrs;
82 
83 #if __cplusplus >= 201103L
84  using allocator_traits = std::allocator_traits<_Alloc>;
85  using _Noexcept_swap
86  = __or_<typename allocator_traits::propagate_on_container_swap,
87  typename allocator_traits::is_always_equal>;
88 #endif
89 
90  public:
91  // Types:
92  typedef _CharT char_type;
93  typedef _Traits traits_type;
94  // _GLIBCXX_RESOLVE_LIB_DEFECTS
95  // 251. basic_stringbuf missing allocator_type
96  typedef _Alloc allocator_type;
97  typedef typename traits_type::int_type int_type;
98  typedef typename traits_type::pos_type pos_type;
99  typedef typename traits_type::off_type off_type;
100 
101  typedef basic_streambuf<char_type, traits_type> __streambuf_type;
102  typedef basic_string<char_type, _Traits, _Alloc> __string_type;
103  typedef typename __string_type::size_type __size_type;
104 
105  protected:
106  /// Place to stash in || out || in | out settings for current stringbuf.
107  ios_base::openmode _M_mode;
108 
109  // Data Members:
110  __string_type _M_string;
111 
112  public:
113  // Constructors:
114 
115  /**
116  * @brief Starts with an empty string buffer.
117  *
118  * The default constructor initializes the parent class using its
119  * own default ctor.
120  */
121  basic_stringbuf()
122  : __streambuf_type(), _M_mode(ios_base::in | ios_base::out), _M_string()
123  { }
124 
125  /**
126  * @brief Starts with an empty string buffer.
127  * @param __mode Whether the buffer can read, or write, or both.
128  *
129  * The default constructor initializes the parent class using its
130  * own default ctor.
131  */
132  explicit
133  basic_stringbuf(ios_base::openmode __mode)
134  : __streambuf_type(), _M_mode(__mode), _M_string()
135  { }
136 
137  /**
138  * @brief Starts with an existing string buffer.
139  * @param __str A string to copy as a starting buffer.
140  * @param __mode Whether the buffer can read, or write, or both.
141  *
142  * This constructor initializes the parent class using its
143  * own default ctor.
144  */
145  explicit
146  basic_stringbuf(const __string_type& __str,
147  ios_base::openmode __mode = ios_base::in | ios_base::out)
148  : __streambuf_type(), _M_mode(),
149  _M_string(__str.data(), __str.size(), __str.get_allocator())
150  { _M_stringbuf_init(__mode); }
151 
152 #if __cplusplus >= 201103L
153  basic_stringbuf(const basic_stringbuf&) = delete;
154 
155  basic_stringbuf(basic_stringbuf&& __rhs)
156  : basic_stringbuf(std::move(__rhs), __xfer_bufptrs(__rhs, this))
157  { __rhs._M_sync(const_cast<char_type*>(__rhs._M_string.data()), 0, 0); }
158 
159 #if __cplusplus > 201703L && _GLIBCXX_USE_CXX11_ABI
160  explicit
161  basic_stringbuf(const allocator_type& __a)
162  : basic_stringbuf(ios_base::in | std::ios_base::out, __a)
163  { }
164 
165  basic_stringbuf(ios_base::openmode __mode,
166  const allocator_type& __a)
167  : __streambuf_type(), _M_mode(__mode), _M_string(__a)
168  { }
169 
170  explicit
171  basic_stringbuf(__string_type&& __s,
172  ios_base::openmode __mode = ios_base::in
173  | ios_base::out)
174  : __streambuf_type(), _M_mode(__mode), _M_string(std::move(__s))
175  { _M_stringbuf_init(__mode); }
176 
177  template<typename _SAlloc>
178  basic_stringbuf(const basic_string<_CharT, _Traits, _SAlloc>& __s,
179  const allocator_type& __a)
180  : basic_stringbuf(__s, ios_base::in | std::ios_base::out, __a)
181  { }
182 
183  template<typename _SAlloc>
184  basic_stringbuf(const basic_string<_CharT, _Traits, _SAlloc>& __s,
185  ios_base::openmode __mode,
186  const allocator_type& __a)
187  : __streambuf_type(), _M_mode(__mode),
188  _M_string(__s.data(), __s.size(), __a)
189  { _M_stringbuf_init(__mode); }
190 
191  template<typename _SAlloc>
192  explicit
193  basic_stringbuf(const basic_string<_CharT, _Traits, _SAlloc>& __s,
194  ios_base::openmode __mode = ios_base::in
195  | ios_base::out)
196  : basic_stringbuf(__s, __mode, allocator_type{})
197  { }
198 
199  basic_stringbuf(basic_stringbuf&& __rhs, const allocator_type& __a)
200  : basic_stringbuf(std::move(__rhs), __a, __xfer_bufptrs(__rhs, this))
201  { __rhs._M_sync(const_cast<char_type*>(__rhs._M_string.data()), 0, 0); }
202 
203  allocator_type get_allocator() const noexcept
204  { return _M_string.get_allocator(); }
205 #endif // C++20
206 
207  // 27.8.2.2 Assign and swap:
208 
209  basic_stringbuf&
210  operator=(const basic_stringbuf&) = delete;
211 
212  basic_stringbuf&
213  operator=(basic_stringbuf&& __rhs)
214  {
215  __xfer_bufptrs __st{__rhs, this};
216  const __streambuf_type& __base = __rhs;
217  __streambuf_type::operator=(__base);
218  this->pubimbue(__rhs.getloc());
219  _M_mode = __rhs._M_mode;
220  _M_string = std::move(__rhs._M_string);
221  __rhs._M_sync(const_cast<char_type*>(__rhs._M_string.data()), 0, 0);
222  return *this;
223  }
224 
225  void
226  swap(basic_stringbuf& __rhs) noexcept(_Noexcept_swap::value)
227  {
228  __xfer_bufptrs __l_st{*this, std::__addressof(__rhs)};
229  __xfer_bufptrs __r_st{__rhs, this};
230  __streambuf_type& __base = __rhs;
231  __streambuf_type::swap(__base);
232  __rhs.pubimbue(this->pubimbue(__rhs.getloc()));
233  std::swap(_M_mode, __rhs._M_mode);
234  std::swap(_M_string, __rhs._M_string); // XXX not exception safe
235  }
236 #endif // C++11
237 
238  // Getters and setters:
239 
240  /**
241  * @brief Copying out the string buffer.
242  * @return A copy of one of the underlying sequences.
243  *
244  * <em>If the buffer is only created in input mode, the underlying
245  * character sequence is equal to the input sequence; otherwise, it
246  * is equal to the output sequence.</em> [27.7.1.2]/1
247  */
248  __string_type
249  str() const _GLIBCXX_LVAL_REF_QUAL
250  {
251  __string_type __ret(_M_string.get_allocator());
252  if (char_type* __hi = _M_high_mark())
253  __ret.assign(this->pbase(), __hi);
254  else
255  __ret = _M_string;
256  return __ret;
257  }
258 
259 #if __cplusplus > 201703L
260 #if _GLIBCXX_USE_CXX11_ABI
261 #if __cpp_concepts
262  template<__allocator_like _SAlloc>
263  basic_string<_CharT, _Traits, _SAlloc>
264  str(const _SAlloc& __sa) const
265  {
266  auto __sv = view();
267  return { __sv.data(), __sv.size(), __sa };
268  }
269 #endif
270 
271  __string_type
272  str() &&
273  {
274  if (char_type* __hi = _M_high_mark())
275  {
276  // Set length to end of character sequence and add null terminator.
277  _M_string._M_set_length(_M_high_mark() - this->pbase());
278  }
279  auto __str = std::move(_M_string);
280  _M_string.clear();
281  _M_sync(_M_string.data(), 0, 0);
282  return __str;
283  }
284 #endif // cxx11 ABI
285 
286  _GLIBCXX_SSTREAM_ALWAYS_INLINE
287  basic_string_view<char_type, traits_type>
288  view() const noexcept
289  {
290  if (char_type* __hi = _M_high_mark())
291  return { this->pbase(), __hi };
292  else
293  return _M_string;
294  }
295 #endif // C++20
296 
297  /**
298  * @brief Setting a new buffer.
299  * @param __s The string to use as a new sequence.
300  *
301  * Deallocates any previous stored sequence, then copies @a s to
302  * use as a new one.
303  */
304  void
305  str(const __string_type& __s)
306  {
307  // Cannot use _M_string = __s, since v3 strings are COW
308  // (not always true now but assign() always works).
309  _M_string.assign(__s.data(), __s.size());
310  _M_stringbuf_init(_M_mode);
311  }
312 
313 #if __cplusplus > 201703L && _GLIBCXX_USE_CXX11_ABI
314 #if __cpp_concepts
315  template<__allocator_like _SAlloc>
316  requires (!is_same_v<_SAlloc, _Alloc>)
317  void
318  str(const basic_string<_CharT, _Traits, _SAlloc>& __s)
319  {
320  _M_string.assign(__s.data(), __s.size());
321  _M_stringbuf_init(_M_mode);
322  }
323 #endif
324 
325  void
326  str(__string_type&& __s)
327  {
328  _M_string = std::move(__s);
329  _M_stringbuf_init(_M_mode);
330  }
331 #endif
332 
333  protected:
334  // Common initialization code goes here.
335  void
336  _M_stringbuf_init(ios_base::openmode __mode)
337  {
338  _M_mode = __mode;
339  __size_type __len = 0;
340  if (_M_mode & (ios_base::ate | ios_base::app))
341  __len = _M_string.size();
342  _M_sync(const_cast<char_type*>(_M_string.data()), 0, __len);
343  }
344 
345  virtual streamsize
346  showmanyc()
347  {
348  streamsize __ret = -1;
349  if (_M_mode & ios_base::in)
350  {
351  _M_update_egptr();
352  __ret = this->egptr() - this->gptr();
353  }
354  return __ret;
355  }
356 
357  virtual int_type
358  underflow();
359 
360  virtual int_type
361  pbackfail(int_type __c = traits_type::eof());
362 
363  virtual int_type
364  overflow(int_type __c = traits_type::eof());
365 
366  /**
367  * @brief Manipulates the buffer.
368  * @param __s Pointer to a buffer area.
369  * @param __n Size of @a __s.
370  * @return @c this
371  *
372  * If no buffer has already been created, and both @a __s and @a __n are
373  * non-zero, then @c __s is used as a buffer; see
374  * https://gcc.gnu.org/onlinedocs/libstdc++/manual/streambufs.html#io.streambuf.buffering
375  * for more.
376  */
377  virtual __streambuf_type*
378  setbuf(char_type* __s, streamsize __n)
379  {
380  if (__s && __n >= 0)
381  {
382  // This is implementation-defined behavior, and assumes
383  // that an external char_type array of length __n exists
384  // and has been pre-allocated. If this is not the case,
385  // things will quickly blow up.
386 
387  // Step 1: Destroy the current internal array.
388  _M_string.clear();
389 
390  // Step 2: Use the external array.
391  _M_sync(__s, __n, 0);
392  }
393  return this;
394  }
395 
396  virtual pos_type
397  seekoff(off_type __off, ios_base::seekdir __way,
398  ios_base::openmode __mode = ios_base::in | ios_base::out);
399 
400  virtual pos_type
401  seekpos(pos_type __sp,
402  ios_base::openmode __mode = ios_base::in | ios_base::out);
403 
404  // Internal function for correctly updating the internal buffer
405  // for a particular _M_string, due to initialization or re-sizing
406  // of an existing _M_string.
407  void
408  _M_sync(char_type* __base, __size_type __i, __size_type __o);
409 
410  // Internal function for correctly updating egptr() to the actual
411  // string end.
412  void
413  _M_update_egptr()
414  {
415  if (char_type* __pptr = this->pptr())
416  {
417  char_type* __egptr = this->egptr();
418  if (!__egptr || __pptr > __egptr)
419  {
420  if (_M_mode & ios_base::in)
421  this->setg(this->eback(), this->gptr(), __pptr);
422  else
423  this->setg(__pptr, __pptr, __pptr);
424  }
425  }
426  }
427 
428  // Works around the issue with pbump, part of the protected
429  // interface of basic_streambuf, taking just an int.
430  void
431  _M_pbump(char_type* __pbeg, char_type* __pend, off_type __off);
432 
433  private:
434  // Return a pointer to the end of the underlying character sequence.
435  // This might not be the same character as _M_string.end() because
436  // basic_stringbuf::overflow might have written to unused capacity
437  // in _M_string without updating its length.
438  __attribute__((__always_inline__))
439  char_type*
440  _M_high_mark() const _GLIBCXX_NOEXCEPT
441  {
442  if (char_type* __pptr = this->pptr())
443  {
444  char_type* __egptr = this->egptr();
445  if (!__egptr || __pptr > __egptr)
446  return __pptr; // Underlying sequence is [pbase, pptr).
447  else
448  return __egptr; // Underlying sequence is [pbase, egptr).
449  }
450  return 0; // Underlying character sequence is just _M_string.
451  }
452 
453 #if __cplusplus >= 201103L
454 #if _GLIBCXX_USE_CXX11_ABI
455  // This type captures the state of the gptr / pptr pointers as offsets
456  // so they can be restored in another object after moving the string.
457  struct __xfer_bufptrs
458  {
459  __xfer_bufptrs(const basic_stringbuf& __from, basic_stringbuf* __to)
460  : _M_to{__to}, _M_goff{-1, -1, -1}, _M_poff{-1, -1, -1}
461  {
462  const _CharT* const __str = __from._M_string.data();
463  const _CharT* __end = nullptr;
464  if (__from.eback())
465  {
466  _M_goff[0] = __from.eback() - __str;
467  _M_goff[1] = __from.gptr() - __str;
468  _M_goff[2] = __from.egptr() - __str;
469  __end = __from.egptr();
470  }
471  if (__from.pbase())
472  {
473  _M_poff[0] = __from.pbase() - __str;
474  _M_poff[1] = __from.pptr() - __from.pbase();
475  _M_poff[2] = __from.epptr() - __str;
476  if (!__end || __from.pptr() > __end)
477  __end = __from.pptr();
478  }
479 
480  // Set _M_string length to the greater of the get and put areas.
481  if (__end)
482  {
483  // The const_cast avoids changing this constructor's signature,
484  // because it is exported from the dynamic library.
485  auto& __mut_from = const_cast<basic_stringbuf&>(__from);
486  __mut_from._M_string._M_length(__end - __str);
487  }
488  }
489 
490  ~__xfer_bufptrs()
491  {
492  char_type* __str = const_cast<char_type*>(_M_to->_M_string.data());
493  if (_M_goff[0] != -1)
494  _M_to->setg(__str+_M_goff[0], __str+_M_goff[1], __str+_M_goff[2]);
495  if (_M_poff[0] != -1)
496  _M_to->_M_pbump(__str+_M_poff[0], __str+_M_poff[2], _M_poff[1]);
497  }
498 
499  basic_stringbuf* _M_to;
500  off_type _M_goff[3];
501  off_type _M_poff[3];
502  };
503 #else
504  // This type does nothing when using Copy-On-Write strings.
505  struct __xfer_bufptrs
506  {
507  __xfer_bufptrs(const basic_stringbuf&, basic_stringbuf*) { }
508  };
509 #endif
510 
511  // The move constructor initializes an __xfer_bufptrs temporary then
512  // delegates to this constructor to performs moves during its lifetime.
513  basic_stringbuf(basic_stringbuf&& __rhs, __xfer_bufptrs&&)
514  : __streambuf_type(static_cast<const __streambuf_type&>(__rhs)),
515  _M_mode(__rhs._M_mode), _M_string(std::move(__rhs._M_string))
516  { }
517 
518 #if __cplusplus > 201703L && _GLIBCXX_USE_CXX11_ABI
519  // The move constructor initializes an __xfer_bufptrs temporary then
520  // delegates to this constructor to performs moves during its lifetime.
521  basic_stringbuf(basic_stringbuf&& __rhs, const allocator_type& __a,
522  __xfer_bufptrs&&)
523  : __streambuf_type(static_cast<const __streambuf_type&>(__rhs)),
524  _M_mode(__rhs._M_mode), _M_string(std::move(__rhs._M_string), __a)
525  { }
526 #endif
527 #endif // C++11
528  };
529 
530 
531  // [27.7.2] Template class basic_istringstream
532  /**
533  * @brief Controlling input for std::string.
534  * @ingroup io
535  *
536  * @tparam _CharT Type of character stream.
537  * @tparam _Traits Traits for character type, defaults to
538  * char_traits<_CharT>.
539  * @tparam _Alloc Allocator type, defaults to allocator<_CharT>.
540  *
541  * This class supports reading from objects of type std::basic_string,
542  * using the inherited functions from std::basic_istream. To control
543  * the associated sequence, an instance of std::basic_stringbuf is used,
544  * which this page refers to as @c sb.
545  */
546  template<typename _CharT, typename _Traits, typename _Alloc>
547  class basic_istringstream : public basic_istream<_CharT, _Traits>
548  {
549  public:
550  // Types:
551  typedef _CharT char_type;
552  typedef _Traits traits_type;
553  // _GLIBCXX_RESOLVE_LIB_DEFECTS
554  // 251. basic_stringbuf missing allocator_type
555  typedef _Alloc allocator_type;
556  typedef typename traits_type::int_type int_type;
557  typedef typename traits_type::pos_type pos_type;
558  typedef typename traits_type::off_type off_type;
559 
560  // Non-standard types:
561  typedef basic_string<_CharT, _Traits, _Alloc> __string_type;
562  typedef basic_stringbuf<_CharT, _Traits, _Alloc> __stringbuf_type;
563  typedef basic_istream<char_type, traits_type> __istream_type;
564 
565  private:
566  __stringbuf_type _M_stringbuf;
567 
568  public:
569  // Constructors:
570 
571  /**
572  * @brief Default constructor starts with an empty string buffer.
573  *
574  * Initializes @c sb using @c in, and passes @c &sb to the base
575  * class initializer. Does not allocate any buffer.
576  *
577  * That's a lie. We initialize the base class with NULL, because the
578  * string class does its own memory management.
579  */
580  basic_istringstream()
581  : __istream_type(), _M_stringbuf(ios_base::in)
582  { this->init(&_M_stringbuf); }
583 
584  /**
585  * @brief Starts with an empty string buffer.
586  * @param __mode Whether the buffer can read, or write, or both.
587  *
588  * @c ios_base::in is automatically included in @a __mode.
589  *
590  * Initializes @c sb using @c __mode|in, and passes @c &sb to the base
591  * class initializer. Does not allocate any buffer.
592  *
593  * That's a lie. We initialize the base class with NULL, because the
594  * string class does its own memory management.
595  */
596  explicit
597  basic_istringstream(ios_base::openmode __mode)
598  : __istream_type(), _M_stringbuf(__mode | ios_base::in)
599  { this->init(&_M_stringbuf); }
600 
601  /**
602  * @brief Starts with an existing string buffer.
603  * @param __str A string to copy as a starting buffer.
604  * @param __mode Whether the buffer can read, or write, or both.
605  *
606  * @c ios_base::in is automatically included in @a mode.
607  *
608  * Initializes @c sb using @a str and @c mode|in, and passes @c &sb
609  * to the base class initializer.
610  *
611  * That's a lie. We initialize the base class with NULL, because the
612  * string class does its own memory management.
613  */
614  explicit
615  basic_istringstream(const __string_type& __str,
616  ios_base::openmode __mode = ios_base::in)
617  : __istream_type(), _M_stringbuf(__str, __mode | ios_base::in)
618  { this->init(&_M_stringbuf); }
619 
620  /**
621  * @brief The destructor does nothing.
622  *
623  * The buffer is deallocated by the stringbuf object, not the
624  * formatting stream.
625  */
626  ~basic_istringstream()
627  { }
628 
629 #if __cplusplus >= 201103L
630  basic_istringstream(const basic_istringstream&) = delete;
631 
632  basic_istringstream(basic_istringstream&& __rhs)
633  : __istream_type(std::move(__rhs)),
634  _M_stringbuf(std::move(__rhs._M_stringbuf))
635  { __istream_type::set_rdbuf(&_M_stringbuf); }
636 
637 #if __cplusplus > 201703L && _GLIBCXX_USE_CXX11_ABI
638  basic_istringstream(ios_base::openmode __mode, const allocator_type& __a)
639  : __istream_type(), _M_stringbuf(__mode | ios_base::in, __a)
640  { this->init(std::__addressof(_M_stringbuf)); }
641 
642  explicit
643  basic_istringstream(__string_type&& __str,
644  ios_base::openmode __mode = ios_base::in)
645  : __istream_type(), _M_stringbuf(std::move(__str), __mode | ios_base::in)
646  { this->init(std::__addressof(_M_stringbuf)); }
647 
648  template<typename _SAlloc>
649  basic_istringstream(const basic_string<_CharT, _Traits, _SAlloc>& __str,
650  const allocator_type& __a)
651  : basic_istringstream(__str, ios_base::in, __a)
652  { }
653 
654  template<typename _SAlloc>
655  basic_istringstream(const basic_string<_CharT, _Traits, _SAlloc>& __str,
656  ios_base::openmode __mode,
657  const allocator_type& __a)
658  : __istream_type(), _M_stringbuf(__str, __mode | ios_base::in, __a)
659  { this->init(std::__addressof(_M_stringbuf)); }
660 
661  template<typename _SAlloc>
662  explicit
663  basic_istringstream(const basic_string<_CharT, _Traits, _SAlloc>& __str,
664  ios_base::openmode __mode = ios_base::in)
665  : basic_istringstream(__str, __mode, allocator_type())
666  { }
667 #endif // C++20
668 
669  // 27.8.3.2 Assign and swap:
670 
671  basic_istringstream&
672  operator=(const basic_istringstream&) = delete;
673 
674  basic_istringstream&
675  operator=(basic_istringstream&& __rhs)
676  {
677  __istream_type::operator=(std::move(__rhs));
678  _M_stringbuf = std::move(__rhs._M_stringbuf);
679  return *this;
680  }
681 
682  void
683  swap(basic_istringstream& __rhs)
684  {
685  __istream_type::swap(__rhs);
686  _M_stringbuf.swap(__rhs._M_stringbuf);
687  }
688 #endif // C++11
689 
690  // Members:
691  /**
692  * @brief Accessing the underlying buffer.
693  * @return The current basic_stringbuf buffer.
694  *
695  * This hides both signatures of std::basic_ios::rdbuf().
696  */
697  __stringbuf_type*
698  rdbuf() const
699  { return const_cast<__stringbuf_type*>(&_M_stringbuf); }
700 
701  /**
702  * @brief Copying out the string buffer.
703  * @return @c rdbuf()->str()
704  */
705  __string_type
706  str() const _GLIBCXX_LVAL_REF_QUAL
707  { return _M_stringbuf.str(); }
708 
709 #if __cplusplus > 201703L
710 #if _GLIBCXX_USE_CXX11_ABI
711 #if __cpp_concepts
712  template<__allocator_like _SAlloc>
713  basic_string<_CharT, _Traits, _SAlloc>
714  str(const _SAlloc& __sa) const
715  { return _M_stringbuf.str(__sa); }
716 #endif
717 
718  __string_type
719  str() &&
720  { return std::move(_M_stringbuf).str(); }
721 #endif // cxx11 ABI
722 
723  _GLIBCXX_SSTREAM_ALWAYS_INLINE
724  basic_string_view<char_type, traits_type>
725  view() const noexcept
726  { return _M_stringbuf.view(); }
727 #endif // C++20
728 
729  /**
730  * @brief Setting a new buffer.
731  * @param __s The string to use as a new sequence.
732  *
733  * Calls @c rdbuf()->str(s).
734  */
735  void
736  str(const __string_type& __s)
737  { _M_stringbuf.str(__s); }
738 
739 #if __cplusplus > 201703L && _GLIBCXX_USE_CXX11_ABI
740 #if __cpp_concepts
741  template<__allocator_like _SAlloc>
742  requires (!is_same_v<_SAlloc, _Alloc>)
743  void
744  str(const basic_string<_CharT, _Traits, _SAlloc>& __s)
745  { _M_stringbuf.str(__s); }
746 #endif
747 
748  void
749  str(__string_type&& __s)
750  { _M_stringbuf.str(std::move(__s)); }
751 #endif
752  };
753 
754 
755  // [27.7.3] Template class basic_ostringstream
756  /**
757  * @brief Controlling output for std::string.
758  * @ingroup io
759  *
760  * @tparam _CharT Type of character stream.
761  * @tparam _Traits Traits for character type, defaults to
762  * char_traits<_CharT>.
763  * @tparam _Alloc Allocator type, defaults to allocator<_CharT>.
764  *
765  * This class supports writing to objects of type std::basic_string,
766  * using the inherited functions from std::basic_ostream. To control
767  * the associated sequence, an instance of std::basic_stringbuf is used,
768  * which this page refers to as @c sb.
769  */
770  template <typename _CharT, typename _Traits, typename _Alloc>
771  class basic_ostringstream : public basic_ostream<_CharT, _Traits>
772  {
773  public:
774  // Types:
775  typedef _CharT char_type;
776  typedef _Traits traits_type;
777  // _GLIBCXX_RESOLVE_LIB_DEFECTS
778  // 251. basic_stringbuf missing allocator_type
779  typedef _Alloc allocator_type;
780  typedef typename traits_type::int_type int_type;
781  typedef typename traits_type::pos_type pos_type;
782  typedef typename traits_type::off_type off_type;
783 
784  // Non-standard types:
785  typedef basic_string<_CharT, _Traits, _Alloc> __string_type;
786  typedef basic_stringbuf<_CharT, _Traits, _Alloc> __stringbuf_type;
787  typedef basic_ostream<char_type, traits_type> __ostream_type;
788 
789  private:
790  __stringbuf_type _M_stringbuf;
791 
792  public:
793  // Constructors/destructor:
794 
795  /**
796  * @brief Default constructor starts with an empty string buffer.
797  *
798  * Initializes @c sb using @c mode|out, and passes @c &sb to the base
799  * class initializer. Does not allocate any buffer.
800  *
801  * That's a lie. We initialize the base class with NULL, because the
802  * string class does its own memory management.
803  */
804  basic_ostringstream()
805  : __ostream_type(), _M_stringbuf(ios_base::out)
806  { this->init(&_M_stringbuf); }
807 
808  /**
809  * @brief Starts with an empty string buffer.
810  * @param __mode Whether the buffer can read, or write, or both.
811  *
812  * @c ios_base::out is automatically included in @a mode.
813  *
814  * Initializes @c sb using @c mode|out, and passes @c &sb to the base
815  * class initializer. Does not allocate any buffer.
816  *
817  * That's a lie. We initialize the base class with NULL, because the
818  * string class does its own memory management.
819  */
820  explicit
821  basic_ostringstream(ios_base::openmode __mode)
822  : __ostream_type(), _M_stringbuf(__mode | ios_base::out)
823  { this->init(&_M_stringbuf); }
824 
825  /**
826  * @brief Starts with an existing string buffer.
827  * @param __str A string to copy as a starting buffer.
828  * @param __mode Whether the buffer can read, or write, or both.
829  *
830  * @c ios_base::out is automatically included in @a mode.
831  *
832  * Initializes @c sb using @a str and @c mode|out, and passes @c &sb
833  * to the base class initializer.
834  *
835  * That's a lie. We initialize the base class with NULL, because the
836  * string class does its own memory management.
837  */
838  explicit
839  basic_ostringstream(const __string_type& __str,
840  ios_base::openmode __mode = ios_base::out)
841  : __ostream_type(), _M_stringbuf(__str, __mode | ios_base::out)
842  { this->init(&_M_stringbuf); }
843 
844  /**
845  * @brief The destructor does nothing.
846  *
847  * The buffer is deallocated by the stringbuf object, not the
848  * formatting stream.
849  */
850  ~basic_ostringstream()
851  { }
852 
853 #if __cplusplus >= 201103L
854  basic_ostringstream(const basic_ostringstream&) = delete;
855 
856  basic_ostringstream(basic_ostringstream&& __rhs)
857  : __ostream_type(std::move(__rhs)),
858  _M_stringbuf(std::move(__rhs._M_stringbuf))
859  { __ostream_type::set_rdbuf(&_M_stringbuf); }
860 
861 #if __cplusplus > 201703L && _GLIBCXX_USE_CXX11_ABI
862  basic_ostringstream(ios_base::openmode __mode, const allocator_type& __a)
863  : __ostream_type(), _M_stringbuf(__mode | ios_base::out, __a)
864  { this->init(std::__addressof(_M_stringbuf)); }
865 
866  explicit
867  basic_ostringstream(__string_type&& __str,
868  ios_base::openmode __mode = ios_base::out)
869  : __ostream_type(), _M_stringbuf(std::move(__str), __mode | ios_base::out)
870  { this->init(std::__addressof(_M_stringbuf)); }
871 
872  template<typename _SAlloc>
873  basic_ostringstream(const basic_string<_CharT, _Traits, _SAlloc>& __str,
874  const allocator_type& __a)
875  : basic_ostringstream(__str, ios_base::out, __a)
876  { }
877 
878  template<typename _SAlloc>
879  basic_ostringstream(const basic_string<_CharT, _Traits, _SAlloc>& __str,
880  ios_base::openmode __mode,
881  const allocator_type& __a)
882  : __ostream_type(), _M_stringbuf(__str, __mode | ios_base::out, __a)
883  { this->init(std::__addressof(_M_stringbuf)); }
884 
885  template<typename _SAlloc>
886  explicit
887  basic_ostringstream(const basic_string<_CharT, _Traits, _SAlloc>& __str,
888  ios_base::openmode __mode = ios_base::out)
889  : basic_ostringstream(__str, __mode, allocator_type())
890  { }
891 #endif // C++20
892 
893  // 27.8.3.2 Assign and swap:
894 
895  basic_ostringstream&
896  operator=(const basic_ostringstream&) = delete;
897 
898  basic_ostringstream&
899  operator=(basic_ostringstream&& __rhs)
900  {
901  __ostream_type::operator=(std::move(__rhs));
902  _M_stringbuf = std::move(__rhs._M_stringbuf);
903  return *this;
904  }
905 
906  void
907  swap(basic_ostringstream& __rhs)
908  {
909  __ostream_type::swap(__rhs);
910  _M_stringbuf.swap(__rhs._M_stringbuf);
911  }
912 #endif // C++11
913 
914  // Members:
915  /**
916  * @brief Accessing the underlying buffer.
917  * @return The current basic_stringbuf buffer.
918  *
919  * This hides both signatures of std::basic_ios::rdbuf().
920  */
921  __stringbuf_type*
922  rdbuf() const
923  { return const_cast<__stringbuf_type*>(&_M_stringbuf); }
924 
925  /**
926  * @brief Copying out the string buffer.
927  * @return @c rdbuf()->str()
928  */
929  __string_type
930  str() const _GLIBCXX_LVAL_REF_QUAL
931  { return _M_stringbuf.str(); }
932 
933 #if __cplusplus > 201703L
934 #if _GLIBCXX_USE_CXX11_ABI
935 #if __cpp_concepts
936  template<__allocator_like _SAlloc>
937  basic_string<_CharT, _Traits, _SAlloc>
938  str(const _SAlloc& __sa) const
939  { return _M_stringbuf.str(__sa); }
940 #endif
941 
942  __string_type
943  str() &&
944  { return std::move(_M_stringbuf).str(); }
945 #endif // cxx11 ABI
946 
947  _GLIBCXX_SSTREAM_ALWAYS_INLINE
948  basic_string_view<char_type, traits_type>
949  view() const noexcept
950  { return _M_stringbuf.view(); }
951 #endif // C++20
952 
953  /**
954  * @brief Setting a new buffer.
955  * @param __s The string to use as a new sequence.
956  *
957  * Calls @c rdbuf()->str(s).
958  */
959  void
960  str(const __string_type& __s)
961  { _M_stringbuf.str(__s); }
962 
963 #if __cplusplus > 201703L && _GLIBCXX_USE_CXX11_ABI
964 #if __cpp_concepts
965  template<__allocator_like _SAlloc>
966  requires (!is_same_v<_SAlloc, _Alloc>)
967  void
968  str(const basic_string<_CharT, _Traits, _SAlloc>& __s)
969  { _M_stringbuf.str(__s); }
970 #endif
971 
972  void
973  str(__string_type&& __s)
974  { _M_stringbuf.str(std::move(__s)); }
975 #endif
976  };
977 
978 
979  // [27.7.4] Template class basic_stringstream
980  /**
981  * @brief Controlling input and output for std::string.
982  * @ingroup io
983  *
984  * @tparam _CharT Type of character stream.
985  * @tparam _Traits Traits for character type, defaults to
986  * char_traits<_CharT>.
987  * @tparam _Alloc Allocator type, defaults to allocator<_CharT>.
988  *
989  * This class supports reading from and writing to objects of type
990  * std::basic_string, using the inherited functions from
991  * std::basic_iostream. To control the associated sequence, an instance
992  * of std::basic_stringbuf is used, which this page refers to as @c sb.
993  */
994  template <typename _CharT, typename _Traits, typename _Alloc>
995  class basic_stringstream : public basic_iostream<_CharT, _Traits>
996  {
997  public:
998  // Types:
999  typedef _CharT char_type;
1000  typedef _Traits traits_type;
1001  // _GLIBCXX_RESOLVE_LIB_DEFECTS
1002  // 251. basic_stringbuf missing allocator_type
1003  typedef _Alloc allocator_type;
1004  typedef typename traits_type::int_type int_type;
1005  typedef typename traits_type::pos_type pos_type;
1006  typedef typename traits_type::off_type off_type;
1007 
1008  // Non-standard Types:
1009  typedef basic_string<_CharT, _Traits, _Alloc> __string_type;
1010  typedef basic_stringbuf<_CharT, _Traits, _Alloc> __stringbuf_type;
1011  typedef basic_iostream<char_type, traits_type> __iostream_type;
1012 
1013  private:
1014  __stringbuf_type _M_stringbuf;
1015 
1016  public:
1017  // Constructors/destructors
1018 
1019  /**
1020  * @brief Default constructor starts with an empty string buffer.
1021  *
1022  * Initializes @c sb using the mode @c in|out, and passes @c &sb
1023  * to the base class initializer. Does not allocate any buffer.
1024  *
1025  * That's a lie. We initialize the base class with NULL, because the
1026  * string class does its own memory management.
1027  */
1028  basic_stringstream()
1029  : __iostream_type(), _M_stringbuf(ios_base::out | ios_base::in)
1030  { this->init(&_M_stringbuf); }
1031 
1032  /**
1033  * @brief Starts with an empty string buffer.
1034  * @param __m Whether the buffer can read, or write, or both.
1035  *
1036  * Initializes @c sb using the mode from @c __m, and passes @c &sb
1037  * to the base class initializer. Does not allocate any buffer.
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(ios_base::openmode __m)
1044  : __iostream_type(), _M_stringbuf(__m)
1045  { this->init(&_M_stringbuf); }
1046 
1047  /**
1048  * @brief Starts with an existing string buffer.
1049  * @param __str A string to copy as a starting buffer.
1050  * @param __m Whether the buffer can read, or write, or both.
1051  *
1052  * Initializes @c sb using @a __str and @c __m, and passes @c &sb
1053  * to the base class initializer.
1054  *
1055  * That's a lie. We initialize the base class with NULL, because the
1056  * string class does its own memory management.
1057  */
1058  explicit
1059  basic_stringstream(const __string_type& __str,
1060  ios_base::openmode __m = ios_base::out | ios_base::in)
1061  : __iostream_type(), _M_stringbuf(__str, __m)
1062  { this->init(&_M_stringbuf); }
1063 
1064  /**
1065  * @brief The destructor does nothing.
1066  *
1067  * The buffer is deallocated by the stringbuf object, not the
1068  * formatting stream.
1069  */
1070  ~basic_stringstream()
1071  { }
1072 
1073 #if __cplusplus >= 201103L
1074  basic_stringstream(const basic_stringstream&) = delete;
1075 
1076  basic_stringstream(basic_stringstream&& __rhs)
1077  : __iostream_type(std::move(__rhs)),
1078  _M_stringbuf(std::move(__rhs._M_stringbuf))
1079  { __iostream_type::set_rdbuf(&_M_stringbuf); }
1080 
1081 #if __cplusplus > 201703L && _GLIBCXX_USE_CXX11_ABI
1082  basic_stringstream(ios_base::openmode __mode, const allocator_type& __a)
1083  : __iostream_type(), _M_stringbuf(__mode, __a)
1084  { this->init(&_M_stringbuf); }
1085 
1086  explicit
1087  basic_stringstream(__string_type&& __str,
1088  ios_base::openmode __mode = ios_base::in
1089  | ios_base::out)
1090  : __iostream_type(), _M_stringbuf(std::move(__str), __mode)
1091  { this->init(std::__addressof(_M_stringbuf)); }
1092 
1093  template<typename _SAlloc>
1094  basic_stringstream(const basic_string<_CharT, _Traits, _SAlloc>& __str,
1095  const allocator_type& __a)
1096  : basic_stringstream(__str, ios_base::in | ios_base::out, __a)
1097  { }
1098 
1099  template<typename _SAlloc>
1100  basic_stringstream(const basic_string<_CharT, _Traits, _SAlloc>& __str,
1101  ios_base::openmode __mode,
1102  const allocator_type& __a)
1103  : __iostream_type(), _M_stringbuf(__str, __mode, __a)
1104  { this->init(std::__addressof(_M_stringbuf)); }
1105 
1106  template<typename _SAlloc>
1107  explicit
1108  basic_stringstream(const basic_string<_CharT, _Traits, _SAlloc>& __str,
1109  ios_base::openmode __mode = ios_base::in
1110  | ios_base::out)
1111  : basic_stringstream(__str, __mode, allocator_type())
1112  { }
1113 #endif // C++20
1114 
1115  // 27.8.3.2 Assign and swap:
1116 
1117  basic_stringstream&
1118  operator=(const basic_stringstream&) = delete;
1119 
1120  basic_stringstream&
1121  operator=(basic_stringstream&& __rhs)
1122  {
1123  __iostream_type::operator=(std::move(__rhs));
1124  _M_stringbuf = std::move(__rhs._M_stringbuf);
1125  return *this;
1126  }
1127 
1128  void
1129  swap(basic_stringstream& __rhs)
1130  {
1131  __iostream_type::swap(__rhs);
1132  _M_stringbuf.swap(__rhs._M_stringbuf);
1133  }
1134 #endif // C++11
1135 
1136  // Members:
1137  /**
1138  * @brief Accessing the underlying buffer.
1139  * @return The current basic_stringbuf buffer.
1140  *
1141  * This hides both signatures of std::basic_ios::rdbuf().
1142  */
1143  __stringbuf_type*
1144  rdbuf() const
1145  { return const_cast<__stringbuf_type*>(&_M_stringbuf); }
1146 
1147  /**
1148  * @brief Copying out the string buffer.
1149  * @return @c rdbuf()->str()
1150  */
1151  __string_type
1152  str() const _GLIBCXX_LVAL_REF_QUAL
1153  { return _M_stringbuf.str(); }
1154 
1155 #if __cplusplus > 201703L
1156 #if _GLIBCXX_USE_CXX11_ABI
1157 #if __cpp_concepts
1158  template<__allocator_like _SAlloc>
1159  basic_string<_CharT, _Traits, _SAlloc>
1160  str(const _SAlloc& __sa) const
1161  { return _M_stringbuf.str(__sa); }
1162 #endif
1163 
1164  __string_type
1165  str() &&
1166  { return std::move(_M_stringbuf).str(); }
1167 #endif // cxx11 ABI
1168 
1169  _GLIBCXX_SSTREAM_ALWAYS_INLINE
1170  basic_string_view<char_type, traits_type>
1171  view() const noexcept
1172  { return _M_stringbuf.view(); }
1173 #endif // C++20
1174 
1175  /**
1176  * @brief Setting a new buffer.
1177  * @param __s The string to use as a new sequence.
1178  *
1179  * Calls @c rdbuf()->str(s).
1180  */
1181  void
1182  str(const __string_type& __s)
1183  { _M_stringbuf.str(__s); }
1184 
1185 #if __cplusplus > 201703L && _GLIBCXX_USE_CXX11_ABI
1186 #if __cpp_concepts
1187  template<__allocator_like _SAlloc>
1188  requires (!is_same_v<_SAlloc, _Alloc>)
1189  void
1190  str(const basic_string<_CharT, _Traits, _SAlloc>& __s)
1191  { _M_stringbuf.str(__s); }
1192 #endif
1193 
1194  void
1195  str(__string_type&& __s)
1196  { _M_stringbuf.str(std::move(__s)); }
1197 #endif
1198  };
1199 
1200 #if __cplusplus >= 201103L
1201  /// Swap specialization for stringbufs.
1202  template <class _CharT, class _Traits, class _Allocator>
1203  inline void
1204  swap(basic_stringbuf<_CharT, _Traits, _Allocator>& __x,
1205  basic_stringbuf<_CharT, _Traits, _Allocator>& __y)
1206  noexcept(noexcept(__x.swap(__y)))
1207  { __x.swap(__y); }
1208 
1209  /// Swap specialization for istringstreams.
1210  template <class _CharT, class _Traits, class _Allocator>
1211  inline void
1212  swap(basic_istringstream<_CharT, _Traits, _Allocator>& __x,
1213  basic_istringstream<_CharT, _Traits, _Allocator>& __y)
1214  { __x.swap(__y); }
1215 
1216  /// Swap specialization for ostringstreams.
1217  template <class _CharT, class _Traits, class _Allocator>
1218  inline void
1219  swap(basic_ostringstream<_CharT, _Traits, _Allocator>& __x,
1220  basic_ostringstream<_CharT, _Traits, _Allocator>& __y)
1221  { __x.swap(__y); }
1222 
1223  /// Swap specialization for stringstreams.
1224  template <class _CharT, class _Traits, class _Allocator>
1225  inline void
1226  swap(basic_stringstream<_CharT, _Traits, _Allocator>& __x,
1227  basic_stringstream<_CharT, _Traits, _Allocator>& __y)
1228  { __x.swap(__y); }
1229 #endif // C++11
1230 
1231 _GLIBCXX_END_NAMESPACE_CXX11
1232 _GLIBCXX_END_NAMESPACE_VERSION
1233 } // namespace
1234 
1235 #undef _GLIBCXX_SSTREAM_ALWAYS_INLINE
1236 #undef _GLIBCXX_LVAL_REF_QUAL
1237 
1238 #include <bits/sstream.tcc>
1239 
1240 #endif /* _GLIBCXX_SSTREAM */