libstdc++
sstream.tcc
Go to the documentation of this file.
1 // String based streams -*- C++ -*-
2 
3 // Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
4 // 2006, 2007, 2008, 2009, 2010, 2011
5 // Free Software Foundation, Inc.
6 //
7 // This file is part of the GNU ISO C++ Library. This library is free
8 // software; you can redistribute it and/or modify it under the
9 // terms of the GNU General Public License as published by the
10 // Free Software Foundation; either version 3, or (at your option)
11 // any later version.
12 
13 // This library is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 // GNU General Public License for more details.
17 
18 // Under Section 7 of GPL version 3, you are granted additional
19 // permissions described in the GCC Runtime Library Exception, version
20 // 3.1, as published by the Free Software Foundation.
21 
22 // You should have received a copy of the GNU General Public License and
23 // a copy of the GCC Runtime Library Exception along with this program;
24 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
25 // <http://www.gnu.org/licenses/>.
26 
27 /** @file bits/sstream.tcc
28  * This is an internal header file, included by other library headers.
29  * Do not attempt to use it directly. @headername{sstream}
30  */
31 
32 //
33 // ISO C++ 14882: 27.7 String-based streams
34 //
35 
36 #ifndef _SSTREAM_TCC
37 #define _SSTREAM_TCC 1
38 
39 #pragma GCC system_header
40 
41 namespace std _GLIBCXX_VISIBILITY(default)
42 {
43 _GLIBCXX_BEGIN_NAMESPACE_VERSION
44 
45  template <class _CharT, class _Traits, class _Alloc>
46  typename basic_stringbuf<_CharT, _Traits, _Alloc>::int_type
48  pbackfail(int_type __c)
49  {
50  int_type __ret = traits_type::eof();
51  if (this->eback() < this->gptr())
52  {
53  // Try to put back __c into input sequence in one of three ways.
54  // Order these tests done in is unspecified by the standard.
55  const bool __testeof = traits_type::eq_int_type(__c, __ret);
56  if (!__testeof)
57  {
58  const bool __testeq = traits_type::eq(traits_type::
59  to_char_type(__c),
60  this->gptr()[-1]);
61  const bool __testout = this->_M_mode & ios_base::out;
62  if (__testeq || __testout)
63  {
64  this->gbump(-1);
65  if (!__testeq)
66  *this->gptr() = traits_type::to_char_type(__c);
67  __ret = __c;
68  }
69  }
70  else
71  {
72  this->gbump(-1);
73  __ret = traits_type::not_eof(__c);
74  }
75  }
76  return __ret;
77  }
78 
79  template <class _CharT, class _Traits, class _Alloc>
80  typename basic_stringbuf<_CharT, _Traits, _Alloc>::int_type
82  overflow(int_type __c)
83  {
84  const bool __testout = this->_M_mode & ios_base::out;
85  if (__builtin_expect(!__testout, false))
86  return traits_type::eof();
87 
88  const bool __testeof = traits_type::eq_int_type(__c, traits_type::eof());
89  if (__builtin_expect(__testeof, false))
90  return traits_type::not_eof(__c);
91 
92  const __size_type __capacity = _M_string.capacity();
93  const __size_type __max_size = _M_string.max_size();
94  const bool __testput = this->pptr() < this->epptr();
95  if (__builtin_expect(!__testput && __capacity == __max_size, false))
96  return traits_type::eof();
97 
98  // Try to append __c into output sequence in one of two ways.
99  // Order these tests done in is unspecified by the standard.
100  const char_type __conv = traits_type::to_char_type(__c);
101  if (!__testput)
102  {
103  // NB: Start ostringstream buffers at 512 chars. This is an
104  // experimental value (pronounced "arbitrary" in some of the
105  // hipper English-speaking countries), and can be changed to
106  // suit particular needs.
107  //
108  // _GLIBCXX_RESOLVE_LIB_DEFECTS
109  // 169. Bad efficiency of overflow() mandated
110  // 432. stringbuf::overflow() makes only one write position
111  // available
112  const __size_type __opt_len = std::max(__size_type(2 * __capacity),
113  __size_type(512));
114  const __size_type __len = std::min(__opt_len, __max_size);
115  __string_type __tmp;
116  __tmp.reserve(__len);
117  if (this->pbase())
118  __tmp.assign(this->pbase(), this->epptr() - this->pbase());
119  __tmp.push_back(__conv);
120  _M_string.swap(__tmp);
121  _M_sync(const_cast<char_type*>(_M_string.data()),
122  this->gptr() - this->eback(), this->pptr() - this->pbase());
123  }
124  else
125  *this->pptr() = __conv;
126  this->pbump(1);
127  return __c;
128  }
129 
130  template <class _CharT, class _Traits, class _Alloc>
131  typename basic_stringbuf<_CharT, _Traits, _Alloc>::int_type
134  {
135  int_type __ret = traits_type::eof();
136  const bool __testin = this->_M_mode & ios_base::in;
137  if (__testin)
138  {
139  // Update egptr() to match the actual string end.
140  _M_update_egptr();
141 
142  if (this->gptr() < this->egptr())
143  __ret = traits_type::to_int_type(*this->gptr());
144  }
145  return __ret;
146  }
147 
148  template <class _CharT, class _Traits, class _Alloc>
149  typename basic_stringbuf<_CharT, _Traits, _Alloc>::pos_type
151  seekoff(off_type __off, ios_base::seekdir __way, ios_base::openmode __mode)
152  {
153  pos_type __ret = pos_type(off_type(-1));
154  bool __testin = (ios_base::in & this->_M_mode & __mode) != 0;
155  bool __testout = (ios_base::out & this->_M_mode & __mode) != 0;
156  const bool __testboth = __testin && __testout && __way != ios_base::cur;
157  __testin &= !(__mode & ios_base::out);
158  __testout &= !(__mode & ios_base::in);
159 
160  // _GLIBCXX_RESOLVE_LIB_DEFECTS
161  // 453. basic_stringbuf::seekoff need not always fail for an empty stream.
162  const char_type* __beg = __testin ? this->eback() : this->pbase();
163  if ((__beg || !__off) && (__testin || __testout || __testboth))
164  {
165  _M_update_egptr();
166 
167  off_type __newoffi = __off;
168  off_type __newoffo = __newoffi;
169  if (__way == ios_base::cur)
170  {
171  __newoffi += this->gptr() - __beg;
172  __newoffo += this->pptr() - __beg;
173  }
174  else if (__way == ios_base::end)
175  __newoffo = __newoffi += this->egptr() - __beg;
176 
177  if ((__testin || __testboth)
178  && __newoffi >= 0
179  && this->egptr() - __beg >= __newoffi)
180  {
181  this->setg(this->eback(), this->eback() + __newoffi,
182  this->egptr());
183  __ret = pos_type(__newoffi);
184  }
185  if ((__testout || __testboth)
186  && __newoffo >= 0
187  && this->egptr() - __beg >= __newoffo)
188  {
189  _M_pbump(this->pbase(), this->epptr(), __newoffo);
190  __ret = pos_type(__newoffo);
191  }
192  }
193  return __ret;
194  }
195 
196  template <class _CharT, class _Traits, class _Alloc>
197  typename basic_stringbuf<_CharT, _Traits, _Alloc>::pos_type
199  seekpos(pos_type __sp, ios_base::openmode __mode)
200  {
201  pos_type __ret = pos_type(off_type(-1));
202  const bool __testin = (ios_base::in & this->_M_mode & __mode) != 0;
203  const bool __testout = (ios_base::out & this->_M_mode & __mode) != 0;
204 
205  const char_type* __beg = __testin ? this->eback() : this->pbase();
206  if ((__beg || !off_type(__sp)) && (__testin || __testout))
207  {
208  _M_update_egptr();
209 
210  const off_type __pos(__sp);
211  const bool __testpos = (0 <= __pos
212  && __pos <= this->egptr() - __beg);
213  if (__testpos)
214  {
215  if (__testin)
216  this->setg(this->eback(), this->eback() + __pos,
217  this->egptr());
218  if (__testout)
219  _M_pbump(this->pbase(), this->epptr(), __pos);
220  __ret = __sp;
221  }
222  }
223  return __ret;
224  }
225 
226  template <class _CharT, class _Traits, class _Alloc>
227  void
229  _M_sync(char_type* __base, __size_type __i, __size_type __o)
230  {
231  const bool __testin = _M_mode & ios_base::in;
232  const bool __testout = _M_mode & ios_base::out;
233  char_type* __endg = __base + _M_string.size();
234  char_type* __endp = __base + _M_string.capacity();
235 
236  if (__base != _M_string.data())
237  {
238  // setbuf: __i == size of buffer area (_M_string.size() == 0).
239  __endg += __i;
240  __i = 0;
241  __endp = __endg;
242  }
243 
244  if (__testin)
245  this->setg(__base, __base + __i, __endg);
246  if (__testout)
247  {
248  _M_pbump(__base, __endp, __o);
249  // egptr() always tracks the string end. When !__testin,
250  // for the correct functioning of the streambuf inlines
251  // the other get area pointers are identical.
252  if (!__testin)
253  this->setg(__endg, __endg, __endg);
254  }
255  }
256 
257  template <class _CharT, class _Traits, class _Alloc>
258  void
259  basic_stringbuf<_CharT, _Traits, _Alloc>::
260  _M_pbump(char_type* __pbeg, char_type* __pend, off_type __off)
261  {
262  this->setp(__pbeg, __pend);
263  while (__off > __gnu_cxx::__numeric_traits<int>::__max)
264  {
265  this->pbump(__gnu_cxx::__numeric_traits<int>::__max);
266  __off -= __gnu_cxx::__numeric_traits<int>::__max;
267  }
268  this->pbump(__off);
269  }
270 
271  // Inhibit implicit instantiations for required instantiations,
272  // which are defined via explicit instantiations elsewhere.
273 #if _GLIBCXX_EXTERN_TEMPLATE
274  extern template class basic_stringbuf<char>;
275  extern template class basic_istringstream<char>;
276  extern template class basic_ostringstream<char>;
277  extern template class basic_stringstream<char>;
278 
279 #ifdef _GLIBCXX_USE_WCHAR_T
280  extern template class basic_stringbuf<wchar_t>;
281  extern template class basic_istringstream<wchar_t>;
282  extern template class basic_ostringstream<wchar_t>;
283  extern template class basic_stringstream<wchar_t>;
284 #endif
285 #endif
286 
287 _GLIBCXX_END_NAMESPACE_VERSION
288 } // namespace std
289 
290 #endif
virtual int_type pbackfail(int_type __c=traits_type::eof())
Tries to back up the input sequence.
Definition: sstream.tcc:48
void push_back(_CharT __c)
Append a single character.
The actual work of input and output (for std::string).This class associates either or both of its inp...
Definition: iosfwd:95
static const seekdir end
Request a seek relative to the current end of the sequence.
Definition: ios_base.h:404
const _Tp & max(const _Tp &, const _Tp &)
This does what you think it does.
Definition: stl_algobase.h:210
_Siter_base< _Iterator >::iterator_type __base(_Iterator __it)
virtual pos_type seekoff(off_type __off, ios_base::seekdir __way, ios_base::openmode __mode=ios_base::in|ios_base::out)
Alters the stream positions.
Definition: sstream.tcc:151
static const openmode in
Open for input. Default for ifstream and fstream.
Definition: ios_base.h:377
virtual int_type overflow(int_type __c=traits_type::eof())
Consumes data from the buffer; writes to the controlled sequence.
Definition: sstream.tcc:82
static const seekdir cur
Request a seek relative to the current position within the sequence.
Definition: ios_base.h:401
static const openmode out
Open for output. Default for ofstream and fstream.
Definition: ios_base.h:380
virtual int_type underflow()
Fetches more data from the controlled sequence.
Definition: sstream.tcc:133
void reserve(size_type __res_arg=0)
Attempt to preallocate enough memory for specified number of characters.
const _Tp & min(const _Tp &, const _Tp &)
This does what you think it does.
Definition: stl_algobase.h:187
basic_string & assign(const basic_string &__str)
Set value to contents of another string.
virtual pos_type seekpos(pos_type __sp, ios_base::openmode __mode=ios_base::in|ios_base::out)
Alters the stream positions.
Definition: sstream.tcc:199