xref: /netbsd-src/external/gpl3/gcc.old/dist/libstdc++-v3/include/std/sstream (revision 63ce0b47aeb8b4c6792d02a0de9ecf8182e299ac)
1// String based streams -*- C++ -*-
2
3// Copyright (C) 1997-2016 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
41namespace std _GLIBCXX_VISIBILITY(default)
42{
43_GLIBCXX_BEGIN_NAMESPACE_VERSION
44_GLIBCXX_BEGIN_NAMESPACE_CXX11
45
46  // [27.7.1] template class basic_stringbuf
47  /**
48   *  @brief  The actual work of input and output (for std::string).
49   *  @ingroup io
50   *
51   *  @tparam _CharT  Type of character stream.
52   *  @tparam _Traits  Traits for character type, defaults to
53   *                   char_traits<_CharT>.
54   *  @tparam _Alloc  Allocator type, defaults to allocator<_CharT>.
55   *
56   *  This class associates either or both of its input and output sequences
57   *  with a sequence of characters, which can be initialized from, or made
58   *  available as, a @c std::basic_string.  (Paraphrased from [27.7.1]/1.)
59   *
60   *  For this class, open modes (of type @c ios_base::openmode) have
61   *  @c in set if the input sequence can be read, and @c out set if the
62   *  output sequence can be written.
63  */
64  template<typename _CharT, typename _Traits, typename _Alloc>
65    class basic_stringbuf : public basic_streambuf<_CharT, _Traits>
66    {
67      struct __xfer_bufptrs;
68    public:
69      // Types:
70      typedef _CharT 					char_type;
71      typedef _Traits 					traits_type;
72      // _GLIBCXX_RESOLVE_LIB_DEFECTS
73      // 251. basic_stringbuf missing allocator_type
74      typedef _Alloc				       	allocator_type;
75      typedef typename traits_type::int_type 		int_type;
76      typedef typename traits_type::pos_type 		pos_type;
77      typedef typename traits_type::off_type 		off_type;
78
79      typedef basic_streambuf<char_type, traits_type>  	__streambuf_type;
80      typedef basic_string<char_type, _Traits, _Alloc> 	__string_type;
81      typedef typename __string_type::size_type		__size_type;
82
83    protected:
84      /// Place to stash in || out || in | out settings for current stringbuf.
85      ios_base::openmode 	_M_mode;
86
87      // Data Members:
88      __string_type 		_M_string;
89
90    public:
91      // Constructors:
92      /**
93       *  @brief  Starts with an empty string buffer.
94       *  @param  __mode  Whether the buffer can read, or write, or both.
95       *
96       *  The default constructor initializes the parent class using its
97       *  own default ctor.
98      */
99      explicit
100      basic_stringbuf(ios_base::openmode __mode = ios_base::in | ios_base::out)
101      : __streambuf_type(), _M_mode(__mode), _M_string()
102      { }
103
104      /**
105       *  @brief  Starts with an existing string buffer.
106       *  @param  __str  A string to copy as a starting buffer.
107       *  @param  __mode  Whether the buffer can read, or write, or both.
108       *
109       *  This constructor initializes the parent class using its
110       *  own default ctor.
111      */
112      explicit
113      basic_stringbuf(const __string_type& __str,
114		      ios_base::openmode __mode = ios_base::in | ios_base::out)
115      : __streambuf_type(), _M_mode(), _M_string(__str.data(), __str.size())
116      { _M_stringbuf_init(__mode); }
117
118#if __cplusplus >= 201103L
119      basic_stringbuf(const basic_stringbuf&) = delete;
120
121      basic_stringbuf(basic_stringbuf&& __rhs)
122      : basic_stringbuf(std::move(__rhs), __xfer_bufptrs(__rhs, this))
123      { __rhs._M_sync(const_cast<char_type*>(__rhs._M_string.data()), 0, 0); }
124
125      // 27.8.2.2 Assign and swap:
126
127      basic_stringbuf&
128      operator=(const basic_stringbuf&) = delete;
129
130      basic_stringbuf&
131      operator=(basic_stringbuf&& __rhs)
132      {
133	__xfer_bufptrs __st{__rhs, this};
134	const __streambuf_type& __base = __rhs;
135	__streambuf_type::operator=(__base);
136	this->pubimbue(__rhs.getloc());
137	_M_mode = __rhs._M_mode;
138	_M_string = std::move(__rhs._M_string);
139	__rhs._M_sync(const_cast<char_type*>(__rhs._M_string.data()), 0, 0);
140	return *this;
141      }
142
143      void
144      swap(basic_stringbuf& __rhs)
145      {
146	__xfer_bufptrs __l_st{*this, std::__addressof(__rhs)};
147	__xfer_bufptrs __r_st{__rhs, this};
148	__streambuf_type& __base = __rhs;
149	__streambuf_type::swap(__base);
150	__rhs.pubimbue(this->pubimbue(__rhs.getloc()));
151	std::swap(_M_mode, __rhs._M_mode);
152	std::swap(_M_string, __rhs._M_string);
153      }
154#endif
155
156      // Get and set:
157      /**
158       *  @brief  Copying out the string buffer.
159       *  @return  A copy of one of the underlying sequences.
160       *
161       *  <em>If the buffer is only created in input mode, the underlying
162       *  character sequence is equal to the input sequence; otherwise, it
163       *  is equal to the output sequence.</em> [27.7.1.2]/1
164      */
165      __string_type
166      str() const
167      {
168	__string_type __ret;
169	if (this->pptr())
170	  {
171	    // The current egptr() may not be the actual string end.
172	    if (this->pptr() > this->egptr())
173	      __ret = __string_type(this->pbase(), this->pptr());
174	    else
175 	      __ret = __string_type(this->pbase(), this->egptr());
176	  }
177	else
178	  __ret = _M_string;
179	return __ret;
180      }
181
182      /**
183       *  @brief  Setting a new buffer.
184       *  @param  __s  The string to use as a new sequence.
185       *
186       *  Deallocates any previous stored sequence, then copies @a s to
187       *  use as a new one.
188      */
189      void
190      str(const __string_type& __s)
191      {
192	// Cannot use _M_string = __s, since v3 strings are COW
193	// (not always true now but assign() always works).
194	_M_string.assign(__s.data(), __s.size());
195	_M_stringbuf_init(_M_mode);
196      }
197
198    protected:
199      // Common initialization code goes here.
200      void
201      _M_stringbuf_init(ios_base::openmode __mode)
202      {
203	_M_mode = __mode;
204	__size_type __len = 0;
205	if (_M_mode & (ios_base::ate | ios_base::app))
206	  __len = _M_string.size();
207	_M_sync(const_cast<char_type*>(_M_string.data()), 0, __len);
208      }
209
210      virtual streamsize
211      showmanyc()
212      {
213	streamsize __ret = -1;
214	if (_M_mode & ios_base::in)
215	  {
216	    _M_update_egptr();
217	    __ret = this->egptr() - this->gptr();
218	  }
219	return __ret;
220      }
221
222      virtual int_type
223      underflow();
224
225      virtual int_type
226      pbackfail(int_type __c = traits_type::eof());
227
228      virtual int_type
229      overflow(int_type __c = traits_type::eof());
230
231      /**
232       *  @brief  Manipulates the buffer.
233       *  @param  __s  Pointer to a buffer area.
234       *  @param  __n  Size of @a __s.
235       *  @return  @c this
236       *
237       *  If no buffer has already been created, and both @a __s and @a __n are
238       *  non-zero, then @c __s is used as a buffer; see
239       *  https://gcc.gnu.org/onlinedocs/libstdc++/manual/streambufs.html#io.streambuf.buffering
240       *  for more.
241      */
242      virtual __streambuf_type*
243      setbuf(char_type* __s, streamsize __n)
244      {
245	if (__s && __n >= 0)
246	  {
247	    // This is implementation-defined behavior, and assumes
248	    // that an external char_type array of length __n exists
249	    // and has been pre-allocated. If this is not the case,
250	    // things will quickly blow up.
251
252	    // Step 1: Destroy the current internal array.
253	    _M_string.clear();
254
255	    // Step 2: Use the external array.
256	    _M_sync(__s, __n, 0);
257	  }
258	return this;
259      }
260
261      virtual pos_type
262      seekoff(off_type __off, ios_base::seekdir __way,
263	      ios_base::openmode __mode = ios_base::in | ios_base::out);
264
265      virtual pos_type
266      seekpos(pos_type __sp,
267	      ios_base::openmode __mode = ios_base::in | ios_base::out);
268
269      // Internal function for correctly updating the internal buffer
270      // for a particular _M_string, due to initialization or re-sizing
271      // of an existing _M_string.
272      void
273      _M_sync(char_type* __base, __size_type __i, __size_type __o);
274
275      // Internal function for correctly updating egptr() to the actual
276      // string end.
277      void
278      _M_update_egptr()
279      {
280	const bool __testin = _M_mode & ios_base::in;
281	if (this->pptr() && this->pptr() > this->egptr())
282	  {
283	    if (__testin)
284	      this->setg(this->eback(), this->gptr(), this->pptr());
285	    else
286	      this->setg(this->pptr(), this->pptr(), this->pptr());
287	  }
288      }
289
290      // Works around the issue with pbump, part of the protected
291      // interface of basic_streambuf, taking just an int.
292      void
293      _M_pbump(char_type* __pbeg, char_type* __pend, off_type __off);
294
295    private:
296#if __cplusplus >= 201103L
297#if _GLIBCXX_USE_CXX11_ABI
298      // This type captures the state of the gptr / pptr pointers as offsets
299      // so they can be restored in another object after moving the string.
300      struct __xfer_bufptrs
301      {
302	__xfer_bufptrs(const basic_stringbuf& __from, basic_stringbuf* __to)
303	: _M_to{__to}, _M_goff{-1, -1, -1}, _M_poff{-1, -1, -1}
304	{
305	  const _CharT* __str = __from._M_string.data();
306	  if (__from.eback())
307	    {
308	    _M_goff[0] = __from.eback() - __str;
309	    _M_goff[1] = __from.gptr() - __str;
310	    _M_goff[2] = __from.egptr() - __str;
311	    }
312	  if (__from.pbase())
313	    {
314	      _M_poff[0] = __from.pbase() - __str;
315	      _M_poff[1] = __from.pptr() - __from.pbase();
316	      _M_poff[2] = __from.epptr() - __str;
317	    }
318	}
319
320	~__xfer_bufptrs()
321	{
322	  char_type* __str = const_cast<char_type*>(_M_to->_M_string.data());
323	  if (_M_goff[0] != -1)
324	    _M_to->setg(__str+_M_goff[0], __str+_M_goff[1], __str+_M_goff[2]);
325	  if (_M_poff[0] != -1)
326	    _M_to->_M_pbump(__str+_M_poff[0], __str+_M_poff[2], _M_poff[1]);
327	}
328
329	basic_stringbuf* _M_to;
330	off_type _M_goff[3];
331	off_type _M_poff[3];
332      };
333#else
334      // This type does nothing when using Copy-On-Write strings.
335      struct __xfer_bufptrs
336      {
337	__xfer_bufptrs(const basic_stringbuf&, basic_stringbuf*) { }
338      };
339#endif
340
341      // The move constructor initializes an __xfer_bufptrs temporary then
342      // delegates to this constructor to performs moves during its lifetime.
343      basic_stringbuf(basic_stringbuf&& __rhs, __xfer_bufptrs&&)
344      : __streambuf_type(static_cast<const __streambuf_type&>(__rhs)),
345      _M_mode(__rhs._M_mode), _M_string(std::move(__rhs._M_string))
346      { }
347#endif
348    };
349
350
351  // [27.7.2] Template class basic_istringstream
352  /**
353   *  @brief  Controlling input for std::string.
354   *  @ingroup io
355   *
356   *  @tparam _CharT  Type of character stream.
357   *  @tparam _Traits  Traits for character type, defaults to
358   *                   char_traits<_CharT>.
359   *  @tparam _Alloc  Allocator type, defaults to allocator<_CharT>.
360   *
361   *  This class supports reading from objects of type std::basic_string,
362   *  using the inherited functions from std::basic_istream.  To control
363   *  the associated sequence, an instance of std::basic_stringbuf is used,
364   *  which this page refers to as @c sb.
365  */
366  template<typename _CharT, typename _Traits, typename _Alloc>
367    class basic_istringstream : public basic_istream<_CharT, _Traits>
368    {
369    public:
370      // Types:
371      typedef _CharT 					char_type;
372      typedef _Traits 					traits_type;
373      // _GLIBCXX_RESOLVE_LIB_DEFECTS
374      // 251. basic_stringbuf missing allocator_type
375      typedef _Alloc				       	allocator_type;
376      typedef typename traits_type::int_type 		int_type;
377      typedef typename traits_type::pos_type 		pos_type;
378      typedef typename traits_type::off_type 		off_type;
379
380      // Non-standard types:
381      typedef basic_string<_CharT, _Traits, _Alloc> 	__string_type;
382      typedef basic_stringbuf<_CharT, _Traits, _Alloc> 	__stringbuf_type;
383      typedef basic_istream<char_type, traits_type>	__istream_type;
384
385    private:
386      __stringbuf_type	_M_stringbuf;
387
388    public:
389      // Constructors:
390      /**
391       *  @brief  Default constructor starts with an empty string buffer.
392       *  @param  __mode  Whether the buffer can read, or write, or both.
393       *
394       *  @c ios_base::in is automatically included in @a __mode.
395       *
396       *  Initializes @c sb using @c __mode|in, and passes @c &sb to the base
397       *  class initializer.  Does not allocate any buffer.
398       *
399       *  That's a lie.  We initialize the base class with NULL, because the
400       *  string class does its own memory management.
401      */
402      explicit
403      basic_istringstream(ios_base::openmode __mode = ios_base::in)
404      : __istream_type(), _M_stringbuf(__mode | ios_base::in)
405      { this->init(&_M_stringbuf); }
406
407      /**
408       *  @brief  Starts with an existing string buffer.
409       *  @param  __str  A string to copy as a starting buffer.
410       *  @param  __mode  Whether the buffer can read, or write, or both.
411       *
412       *  @c ios_base::in is automatically included in @a mode.
413       *
414       *  Initializes @c sb using @a str and @c mode|in, and passes @c &sb
415       *  to the base class initializer.
416       *
417       *  That's a lie.  We initialize the base class with NULL, because the
418       *  string class does its own memory management.
419      */
420      explicit
421      basic_istringstream(const __string_type& __str,
422			  ios_base::openmode __mode = ios_base::in)
423      : __istream_type(), _M_stringbuf(__str, __mode | ios_base::in)
424      { this->init(&_M_stringbuf); }
425
426      /**
427       *  @brief  The destructor does nothing.
428       *
429       *  The buffer is deallocated by the stringbuf object, not the
430       *  formatting stream.
431      */
432      ~basic_istringstream()
433      { }
434
435#if __cplusplus >= 201103L
436      basic_istringstream(const basic_istringstream&) = delete;
437
438      basic_istringstream(basic_istringstream&& __rhs)
439      : __istream_type(std::move(__rhs)),
440      _M_stringbuf(std::move(__rhs._M_stringbuf))
441      { __istream_type::set_rdbuf(&_M_stringbuf); }
442
443      // 27.8.3.2 Assign and swap:
444
445      basic_istringstream&
446      operator=(const basic_istringstream&) = delete;
447
448      basic_istringstream&
449      operator=(basic_istringstream&& __rhs)
450      {
451	__istream_type::operator=(std::move(__rhs));
452	_M_stringbuf = std::move(__rhs._M_stringbuf);
453	return *this;
454      }
455
456      void
457      swap(basic_istringstream& __rhs)
458      {
459	__istream_type::swap(__rhs);
460	_M_stringbuf.swap(__rhs._M_stringbuf);
461      }
462#endif
463
464      // Members:
465      /**
466       *  @brief  Accessing the underlying buffer.
467       *  @return  The current basic_stringbuf buffer.
468       *
469       *  This hides both signatures of std::basic_ios::rdbuf().
470      */
471      __stringbuf_type*
472      rdbuf() const
473      { return const_cast<__stringbuf_type*>(&_M_stringbuf); }
474
475      /**
476       *  @brief  Copying out the string buffer.
477       *  @return  @c rdbuf()->str()
478      */
479      __string_type
480      str() const
481      { return _M_stringbuf.str(); }
482
483      /**
484       *  @brief  Setting a new buffer.
485       *  @param  __s  The string to use as a new sequence.
486       *
487       *  Calls @c rdbuf()->str(s).
488      */
489      void
490      str(const __string_type& __s)
491      { _M_stringbuf.str(__s); }
492    };
493
494
495  // [27.7.3] Template class basic_ostringstream
496  /**
497   *  @brief  Controlling output for std::string.
498   *  @ingroup io
499   *
500   *  @tparam _CharT  Type of character stream.
501   *  @tparam _Traits  Traits for character type, defaults to
502   *                   char_traits<_CharT>.
503   *  @tparam _Alloc  Allocator type, defaults to allocator<_CharT>.
504   *
505   *  This class supports writing to objects of type std::basic_string,
506   *  using the inherited functions from std::basic_ostream.  To control
507   *  the associated sequence, an instance of std::basic_stringbuf is used,
508   *  which this page refers to as @c sb.
509  */
510  template <typename _CharT, typename _Traits, typename _Alloc>
511    class basic_ostringstream : public basic_ostream<_CharT, _Traits>
512    {
513    public:
514      // Types:
515      typedef _CharT 					char_type;
516      typedef _Traits 					traits_type;
517      // _GLIBCXX_RESOLVE_LIB_DEFECTS
518      // 251. basic_stringbuf missing allocator_type
519      typedef _Alloc				       	allocator_type;
520      typedef typename traits_type::int_type 		int_type;
521      typedef typename traits_type::pos_type 		pos_type;
522      typedef typename traits_type::off_type 		off_type;
523
524      // Non-standard types:
525      typedef basic_string<_CharT, _Traits, _Alloc> 	__string_type;
526      typedef basic_stringbuf<_CharT, _Traits, _Alloc> 	__stringbuf_type;
527      typedef basic_ostream<char_type, traits_type>	__ostream_type;
528
529    private:
530      __stringbuf_type	_M_stringbuf;
531
532    public:
533      // Constructors/destructor:
534      /**
535       *  @brief  Default constructor starts with an empty string buffer.
536       *  @param  __mode  Whether the buffer can read, or write, or both.
537       *
538       *  @c ios_base::out is automatically included in @a mode.
539       *
540       *  Initializes @c sb using @c mode|out, and passes @c &sb to the base
541       *  class initializer.  Does not allocate any buffer.
542       *
543       *  That's a lie.  We initialize the base class with NULL, because the
544       *  string class does its own memory management.
545      */
546      explicit
547      basic_ostringstream(ios_base::openmode __mode = ios_base::out)
548      : __ostream_type(), _M_stringbuf(__mode | ios_base::out)
549      { this->init(&_M_stringbuf); }
550
551      /**
552       *  @brief  Starts with an existing string buffer.
553       *  @param  __str  A string to copy as a starting buffer.
554       *  @param  __mode  Whether the buffer can read, or write, or both.
555       *
556       *  @c ios_base::out is automatically included in @a mode.
557       *
558       *  Initializes @c sb using @a str and @c mode|out, and passes @c &sb
559       *  to the base class initializer.
560       *
561       *  That's a lie.  We initialize the base class with NULL, because the
562       *  string class does its own memory management.
563      */
564      explicit
565      basic_ostringstream(const __string_type& __str,
566			  ios_base::openmode __mode = ios_base::out)
567      : __ostream_type(), _M_stringbuf(__str, __mode | ios_base::out)
568      { this->init(&_M_stringbuf); }
569
570      /**
571       *  @brief  The destructor does nothing.
572       *
573       *  The buffer is deallocated by the stringbuf object, not the
574       *  formatting stream.
575      */
576      ~basic_ostringstream()
577      { }
578
579#if __cplusplus >= 201103L
580      basic_ostringstream(const basic_ostringstream&) = delete;
581
582      basic_ostringstream(basic_ostringstream&& __rhs)
583      : __ostream_type(std::move(__rhs)),
584      _M_stringbuf(std::move(__rhs._M_stringbuf))
585      { __ostream_type::set_rdbuf(&_M_stringbuf); }
586
587      // 27.8.3.2 Assign and swap:
588
589      basic_ostringstream&
590      operator=(const basic_ostringstream&) = delete;
591
592      basic_ostringstream&
593      operator=(basic_ostringstream&& __rhs)
594      {
595	__ostream_type::operator=(std::move(__rhs));
596	_M_stringbuf = std::move(__rhs._M_stringbuf);
597	return *this;
598      }
599
600      void
601      swap(basic_ostringstream& __rhs)
602      {
603	__ostream_type::swap(__rhs);
604	_M_stringbuf.swap(__rhs._M_stringbuf);
605      }
606#endif
607
608      // Members:
609      /**
610       *  @brief  Accessing the underlying buffer.
611       *  @return  The current basic_stringbuf buffer.
612       *
613       *  This hides both signatures of std::basic_ios::rdbuf().
614      */
615      __stringbuf_type*
616      rdbuf() const
617      { return const_cast<__stringbuf_type*>(&_M_stringbuf); }
618
619      /**
620       *  @brief  Copying out the string buffer.
621       *  @return  @c rdbuf()->str()
622      */
623      __string_type
624      str() const
625      { return _M_stringbuf.str(); }
626
627      /**
628       *  @brief  Setting a new buffer.
629       *  @param  __s  The string to use as a new sequence.
630       *
631       *  Calls @c rdbuf()->str(s).
632      */
633      void
634      str(const __string_type& __s)
635      { _M_stringbuf.str(__s); }
636    };
637
638
639  // [27.7.4] Template class basic_stringstream
640  /**
641   *  @brief  Controlling input and output for std::string.
642   *  @ingroup io
643   *
644   *  @tparam _CharT  Type of character stream.
645   *  @tparam _Traits  Traits for character type, defaults to
646   *                   char_traits<_CharT>.
647   *  @tparam _Alloc  Allocator type, defaults to allocator<_CharT>.
648   *
649   *  This class supports reading from and writing to objects of type
650   *  std::basic_string, using the inherited functions from
651   *  std::basic_iostream.  To control the associated sequence, an instance
652   *  of std::basic_stringbuf is used, which this page refers to as @c sb.
653  */
654  template <typename _CharT, typename _Traits, typename _Alloc>
655    class basic_stringstream : public basic_iostream<_CharT, _Traits>
656    {
657    public:
658      // Types:
659      typedef _CharT 					char_type;
660      typedef _Traits 					traits_type;
661      // _GLIBCXX_RESOLVE_LIB_DEFECTS
662      // 251. basic_stringbuf missing allocator_type
663      typedef _Alloc				       	allocator_type;
664      typedef typename traits_type::int_type 		int_type;
665      typedef typename traits_type::pos_type 		pos_type;
666      typedef typename traits_type::off_type 		off_type;
667
668      // Non-standard Types:
669      typedef basic_string<_CharT, _Traits, _Alloc> 	__string_type;
670      typedef basic_stringbuf<_CharT, _Traits, _Alloc> 	__stringbuf_type;
671      typedef basic_iostream<char_type, traits_type>	__iostream_type;
672
673    private:
674      __stringbuf_type	_M_stringbuf;
675
676    public:
677      // Constructors/destructors
678      /**
679       *  @brief  Default constructor starts with an empty string buffer.
680       *  @param  __m  Whether the buffer can read, or write, or both.
681       *
682       *  Initializes @c sb using the mode from @c __m, and passes @c
683       *  &sb to the base class initializer.  Does not allocate any
684       *  buffer.
685       *
686       *  That's a lie.  We initialize the base class with NULL, because the
687       *  string class does its own memory management.
688      */
689      explicit
690      basic_stringstream(ios_base::openmode __m = ios_base::out | ios_base::in)
691      : __iostream_type(), _M_stringbuf(__m)
692      { this->init(&_M_stringbuf); }
693
694      /**
695       *  @brief  Starts with an existing string buffer.
696       *  @param  __str  A string to copy as a starting buffer.
697       *  @param  __m  Whether the buffer can read, or write, or both.
698       *
699       *  Initializes @c sb using @a __str and @c __m, and passes @c &sb
700       *  to the base class initializer.
701       *
702       *  That's a lie.  We initialize the base class with NULL, because the
703       *  string class does its own memory management.
704      */
705      explicit
706      basic_stringstream(const __string_type& __str,
707			 ios_base::openmode __m = ios_base::out | ios_base::in)
708      : __iostream_type(), _M_stringbuf(__str, __m)
709      { this->init(&_M_stringbuf); }
710
711      /**
712       *  @brief  The destructor does nothing.
713       *
714       *  The buffer is deallocated by the stringbuf object, not the
715       *  formatting stream.
716      */
717      ~basic_stringstream()
718      { }
719
720#if __cplusplus >= 201103L
721      basic_stringstream(const basic_stringstream&) = delete;
722
723      basic_stringstream(basic_stringstream&& __rhs)
724      : __iostream_type(std::move(__rhs)),
725      _M_stringbuf(std::move(__rhs._M_stringbuf))
726      { __iostream_type::set_rdbuf(&_M_stringbuf); }
727
728      // 27.8.3.2 Assign and swap:
729
730      basic_stringstream&
731      operator=(const basic_stringstream&) = delete;
732
733      basic_stringstream&
734      operator=(basic_stringstream&& __rhs)
735      {
736	__iostream_type::operator=(std::move(__rhs));
737	_M_stringbuf = std::move(__rhs._M_stringbuf);
738	return *this;
739      }
740
741      void
742      swap(basic_stringstream& __rhs)
743      {
744	__iostream_type::swap(__rhs);
745	_M_stringbuf.swap(__rhs._M_stringbuf);
746      }
747#endif
748
749      // Members:
750      /**
751       *  @brief  Accessing the underlying buffer.
752       *  @return  The current basic_stringbuf buffer.
753       *
754       *  This hides both signatures of std::basic_ios::rdbuf().
755      */
756      __stringbuf_type*
757      rdbuf() const
758      { return const_cast<__stringbuf_type*>(&_M_stringbuf); }
759
760      /**
761       *  @brief  Copying out the string buffer.
762       *  @return  @c rdbuf()->str()
763      */
764      __string_type
765      str() const
766      { return _M_stringbuf.str(); }
767
768      /**
769       *  @brief  Setting a new buffer.
770       *  @param  __s  The string to use as a new sequence.
771       *
772       *  Calls @c rdbuf()->str(s).
773      */
774      void
775      str(const __string_type& __s)
776      { _M_stringbuf.str(__s); }
777    };
778
779#if __cplusplus >= 201103L
780  /// Swap specialization for stringbufs.
781  template <class _CharT, class _Traits, class _Allocator>
782    inline void
783    swap(basic_stringbuf<_CharT, _Traits, _Allocator>& __x,
784	 basic_stringbuf<_CharT, _Traits, _Allocator>& __y)
785    { __x.swap(__y); }
786
787  /// Swap specialization for istringstreams.
788  template <class _CharT, class _Traits, class _Allocator>
789    inline void
790    swap(basic_istringstream<_CharT, _Traits, _Allocator>& __x,
791	 basic_istringstream<_CharT, _Traits, _Allocator>& __y)
792    { __x.swap(__y); }
793
794  /// Swap specialization for ostringstreams.
795  template <class _CharT, class _Traits, class _Allocator>
796    inline void
797    swap(basic_ostringstream<_CharT, _Traits, _Allocator>& __x,
798	 basic_ostringstream<_CharT, _Traits, _Allocator>& __y)
799    { __x.swap(__y); }
800
801  /// Swap specialization for stringstreams.
802  template <class _CharT, class _Traits, class _Allocator>
803    inline void
804    swap(basic_stringstream<_CharT, _Traits, _Allocator>& __x,
805	 basic_stringstream<_CharT, _Traits, _Allocator>& __y)
806    { __x.swap(__y); }
807#endif
808
809_GLIBCXX_END_NAMESPACE_CXX11
810_GLIBCXX_END_NAMESPACE_VERSION
811} // namespace
812
813#include <bits/sstream.tcc>
814
815#endif /* _GLIBCXX_SSTREAM */
816