libstdc++
sstream
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1// String based streams -*- C++ -*-
2
3// Copyright (C) 1997-2023 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
55namespace 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 */