1// String based streams -*- C++ -*-
2
3// Copyright (C) 1997-2021 Free Software Foundation, Inc.
4//
5// This file is part of the GNU ISO C++ Library. This library is free
6// software; you can redistribute it and/or modify it under the
7// terms of the GNU General Public License as published by the
8// Free Software Foundation; either version 3, or (at your option)
9// any later version.
10
11// This library is distributed in the hope that it will be useful,
12// but WITHOUT ANY WARRANTY; without even the implied warranty of
13// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14// GNU General Public License for more details.
15
16// Under Section 7 of GPL version 3, you are granted additional
17// permissions described in the GCC Runtime Library Exception, version
18// 3.1, as published by the Free Software Foundation.
19
20// You should have received a copy of the GNU General Public License and
21// a copy of the GCC Runtime Library Exception along with this program;
22// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23// <http://www.gnu.org/licenses/>.
24
25/** @file 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
48namespace 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(base: _M_string.data(), i: 0, o: 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(mode: _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(mode: _M_mode);
312 }
313#endif
314
315 void
316 str(__string_type&& __s)
317 {
318 _M_string = std::move(__s);
319 _M_stringbuf_init(mode: _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(base: const_cast<char_type*>(_M_string.data()), i: 0, o: __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(base: __s, i: __n, o: 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 */
1221

source code of include/c++/11/sstream