libstdc++
sstream.tcc
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1 // String based streams -*- C++ -*-
2 
3 // Copyright (C) 1997-2015 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 bits/sstream.tcc
26  * This is an internal header file, included by other library headers.
27  * Do not attempt to use it directly. @headername{sstream}
28  */
29 
30 //
31 // ISO C++ 14882: 27.7 String-based streams
32 //
33 
34 #ifndef _SSTREAM_TCC
35 #define _SSTREAM_TCC 1
36 
37 #pragma GCC system_header
38 
39 namespace std _GLIBCXX_VISIBILITY(default)
40 {
41 _GLIBCXX_BEGIN_NAMESPACE_VERSION
42 
43  template <class _CharT, class _Traits, class _Alloc>
44  typename basic_stringbuf<_CharT, _Traits, _Alloc>::int_type
46  pbackfail(int_type __c)
47  {
48  int_type __ret = traits_type::eof();
49  if (this->eback() < this->gptr())
50  {
51  // Try to put back __c into input sequence in one of three ways.
52  // Order these tests done in is unspecified by the standard.
53  const bool __testeof = traits_type::eq_int_type(__c, __ret);
54  if (!__testeof)
55  {
56  const bool __testeq = traits_type::eq(traits_type::
57  to_char_type(__c),
58  this->gptr()[-1]);
59  const bool __testout = this->_M_mode & ios_base::out;
60  if (__testeq || __testout)
61  {
62  this->gbump(-1);
63  if (!__testeq)
64  *this->gptr() = traits_type::to_char_type(__c);
65  __ret = __c;
66  }
67  }
68  else
69  {
70  this->gbump(-1);
71  __ret = traits_type::not_eof(__c);
72  }
73  }
74  return __ret;
75  }
76 
77  template <class _CharT, class _Traits, class _Alloc>
78  typename basic_stringbuf<_CharT, _Traits, _Alloc>::int_type
80  overflow(int_type __c)
81  {
82  const bool __testout = this->_M_mode & ios_base::out;
83  if (__builtin_expect(!__testout, false))
84  return traits_type::eof();
85 
86  const bool __testeof = traits_type::eq_int_type(__c, traits_type::eof());
87  if (__builtin_expect(__testeof, false))
88  return traits_type::not_eof(__c);
89 
90  const __size_type __capacity = _M_string.capacity();
91  const __size_type __max_size = _M_string.max_size();
92  const bool __testput = this->pptr() < this->epptr();
93  if (__builtin_expect(!__testput && __capacity == __max_size, false))
94  return traits_type::eof();
95 
96  // Try to append __c into output sequence in one of two ways.
97  // Order these tests done in is unspecified by the standard.
98  const char_type __conv = traits_type::to_char_type(__c);
99  if (!__testput)
100  {
101  // NB: Start ostringstream buffers at 512 chars. This is an
102  // experimental value (pronounced "arbitrary" in some of the
103  // hipper English-speaking countries), and can be changed to
104  // suit particular needs.
105  //
106  // _GLIBCXX_RESOLVE_LIB_DEFECTS
107  // 169. Bad efficiency of overflow() mandated
108  // 432. stringbuf::overflow() makes only one write position
109  // available
110  const __size_type __opt_len = std::max(__size_type(2 * __capacity),
111  __size_type(512));
112  const __size_type __len = std::min(__opt_len, __max_size);
113  __string_type __tmp;
114  __tmp.reserve(__len);
115  if (this->pbase())
116  __tmp.assign(this->pbase(), this->epptr() - this->pbase());
117  __tmp.push_back(__conv);
118  _M_string.swap(__tmp);
119  _M_sync(const_cast<char_type*>(_M_string.data()),
120  this->gptr() - this->eback(), this->pptr() - this->pbase());
121  }
122  else
123  *this->pptr() = __conv;
124  this->pbump(1);
125  return __c;
126  }
127 
128  template <class _CharT, class _Traits, class _Alloc>
129  typename basic_stringbuf<_CharT, _Traits, _Alloc>::int_type
132  {
133  int_type __ret = traits_type::eof();
134  const bool __testin = this->_M_mode & ios_base::in;
135  if (__testin)
136  {
137  // Update egptr() to match the actual string end.
138  _M_update_egptr();
139 
140  if (this->gptr() < this->egptr())
141  __ret = traits_type::to_int_type(*this->gptr());
142  }
143  return __ret;
144  }
145 
146  template <class _CharT, class _Traits, class _Alloc>
147  typename basic_stringbuf<_CharT, _Traits, _Alloc>::pos_type
149  seekoff(off_type __off, ios_base::seekdir __way, ios_base::openmode __mode)
150  {
151  pos_type __ret = pos_type(off_type(-1));
152  bool __testin = (ios_base::in & this->_M_mode & __mode) != 0;
153  bool __testout = (ios_base::out & this->_M_mode & __mode) != 0;
154  const bool __testboth = __testin && __testout && __way != ios_base::cur;
155  __testin &= !(__mode & ios_base::out);
156  __testout &= !(__mode & ios_base::in);
157 
158  // _GLIBCXX_RESOLVE_LIB_DEFECTS
159  // 453. basic_stringbuf::seekoff need not always fail for an empty stream.
160  const char_type* __beg = __testin ? this->eback() : this->pbase();
161  if ((__beg || !__off) && (__testin || __testout || __testboth))
162  {
163  _M_update_egptr();
164 
165  off_type __newoffi = __off;
166  off_type __newoffo = __newoffi;
167  if (__way == ios_base::cur)
168  {
169  __newoffi += this->gptr() - __beg;
170  __newoffo += this->pptr() - __beg;
171  }
172  else if (__way == ios_base::end)
173  __newoffo = __newoffi += this->egptr() - __beg;
174 
175  if ((__testin || __testboth)
176  && __newoffi >= 0
177  && this->egptr() - __beg >= __newoffi)
178  {
179  this->setg(this->eback(), this->eback() + __newoffi,
180  this->egptr());
181  __ret = pos_type(__newoffi);
182  }
183  if ((__testout || __testboth)
184  && __newoffo >= 0
185  && this->egptr() - __beg >= __newoffo)
186  {
187  _M_pbump(this->pbase(), this->epptr(), __newoffo);
188  __ret = pos_type(__newoffo);
189  }
190  }
191  return __ret;
192  }
193 
194  template <class _CharT, class _Traits, class _Alloc>
195  typename basic_stringbuf<_CharT, _Traits, _Alloc>::pos_type
197  seekpos(pos_type __sp, ios_base::openmode __mode)
198  {
199  pos_type __ret = pos_type(off_type(-1));
200  const bool __testin = (ios_base::in & this->_M_mode & __mode) != 0;
201  const bool __testout = (ios_base::out & this->_M_mode & __mode) != 0;
202 
203  const char_type* __beg = __testin ? this->eback() : this->pbase();
204  if ((__beg || !off_type(__sp)) && (__testin || __testout))
205  {
206  _M_update_egptr();
207 
208  const off_type __pos(__sp);
209  const bool __testpos = (0 <= __pos
210  && __pos <= this->egptr() - __beg);
211  if (__testpos)
212  {
213  if (__testin)
214  this->setg(this->eback(), this->eback() + __pos,
215  this->egptr());
216  if (__testout)
217  _M_pbump(this->pbase(), this->epptr(), __pos);
218  __ret = __sp;
219  }
220  }
221  return __ret;
222  }
223 
224  template <class _CharT, class _Traits, class _Alloc>
225  void
227  _M_sync(char_type* __base, __size_type __i, __size_type __o)
228  {
229  const bool __testin = _M_mode & ios_base::in;
230  const bool __testout = _M_mode & ios_base::out;
231  char_type* __endg = __base + _M_string.size();
232  char_type* __endp = __base + _M_string.capacity();
233 
234  if (__base != _M_string.data())
235  {
236  // setbuf: __i == size of buffer area (_M_string.size() == 0).
237  __endg += __i;
238  __i = 0;
239  __endp = __endg;
240  }
241 
242  if (__testin)
243  this->setg(__base, __base + __i, __endg);
244  if (__testout)
245  {
246  _M_pbump(__base, __endp, __o);
247  // egptr() always tracks the string end. When !__testin,
248  // for the correct functioning of the streambuf inlines
249  // the other get area pointers are identical.
250  if (!__testin)
251  this->setg(__endg, __endg, __endg);
252  }
253  }
254 
255  template <class _CharT, class _Traits, class _Alloc>
256  void
258  _M_pbump(char_type* __pbeg, char_type* __pend, off_type __off)
259  {
260  this->setp(__pbeg, __pend);
261  while (__off > __gnu_cxx::__numeric_traits<int>::__max)
262  {
263  this->pbump(__gnu_cxx::__numeric_traits<int>::__max);
264  __off -= __gnu_cxx::__numeric_traits<int>::__max;
265  }
266  this->pbump(__off);
267  }
268 
269  // Inhibit implicit instantiations for required instantiations,
270  // which are defined via explicit instantiations elsewhere.
271 #if _GLIBCXX_EXTERN_TEMPLATE
272  extern template class basic_stringbuf<char>;
273  extern template class basic_istringstream<char>;
274  extern template class basic_ostringstream<char>;
275  extern template class basic_stringstream<char>;
276 
277 #ifdef _GLIBCXX_USE_WCHAR_T
278  extern template class basic_stringbuf<wchar_t>;
279  extern template class basic_istringstream<wchar_t>;
280  extern template class basic_ostringstream<wchar_t>;
281  extern template class basic_stringstream<wchar_t>;
282 #endif
283 #endif
284 
285 _GLIBCXX_END_NAMESPACE_VERSION
286 } // namespace std
287 
288 #endif
virtual int_type underflow()
Fetches more data from the controlled sequence.
Definition: sstream.tcc:131
The actual work of input and output (for std::string).
Definition: iosfwd:96
static const seekdir cur
Request a seek relative to the current position within the sequence.
Definition: ios_base.h:467
basic_string & assign(const basic_string &__str)
Set value to contents of another string.
Controlling input and output for std::string.
Definition: iosfwd:108
virtual int_type overflow(int_type __c=traits_type::eof())
Consumes data from the buffer; writes to the controlled sequence.
Definition: sstream.tcc:80
static const openmode out
Open for output. Default for ofstream and fstream.
Definition: ios_base.h:446
_GLIBCXX14_CONSTEXPR const _Tp & min(const _Tp &, const _Tp &)
This does what you think it does.
Definition: stl_algobase.h:195
_GLIBCXX14_CONSTEXPR const _Tp & max(const _Tp &, const _Tp &)
This does what you think it does.
Definition: stl_algobase.h:219
static const openmode in
Open for input. Default for ifstream and fstream.
Definition: ios_base.h:443
static const seekdir end
Request a seek relative to the current end of the sequence.
Definition: ios_base.h:470
void reserve(size_type __res_arg=0)
Attempt to preallocate enough memory for specified number of characters.
virtual pos_type seekpos(pos_type __sp, ios_base::openmode __mode=ios_base::in|ios_base::out)
Alters the stream positions.
Definition: sstream.tcc:197
Controlling input for std::string.
Definition: iosfwd:100
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:149
Controlling output for std::string.
Definition: iosfwd:104
virtual int_type pbackfail(int_type __c=traits_type::eof())
Tries to back up the input sequence.
Definition: sstream.tcc:46
_Siter_base< _Iterator >::iterator_type __base(_Iterator __it)
Definition: functions.h:558
void push_back(_CharT __c)
Append a single character.
ISO C++ entities toplevel namespace is std.