summaryrefslogtreecommitdiff
path: root/libstdc++-v3/include/bits/basic_ios.h
blob: 29d8ae5d3ed0d7223f62ff394e0314d735ac972d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
// Iostreams base classes -*- C++ -*-

// Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
// 2006, 2007, 2008, 2009, 2010, 2011
// Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.

// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.

// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
// <http://www.gnu.org/licenses/>.

/** @file bits/basic_ios.h
 *  This is an internal header file, included by other library headers.
 *  Do not attempt to use it directly. @headername{ios}
 */

#ifndef _BASIC_IOS_H
#define _BASIC_IOS_H 1

#pragma GCC system_header

#include <bits/localefwd.h>
#include <bits/locale_classes.h>
#include <bits/locale_facets.h>
#include <bits/streambuf_iterator.h>

namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION

  template<typename _Facet>
    inline const _Facet&
    __check_facet(const _Facet* __f)
    {
      if (!__f)
	__throw_bad_cast();
      return *__f;
    }

  // 27.4.5  Template class basic_ios
  /**
   *  @brief  Virtual base class for all stream classes.
   *  @ingroup io
   *
   *  Most of the member functions called dispatched on stream objects
   *  (e.g., @c std::cout.foo(bar);) are consolidated in this class.
  */
  template<typename _CharT, typename _Traits>
    class basic_ios : public ios_base
    {
    public:
      //@{
      /**
       *  These are standard types.  They permit a standardized way of
       *  referring to names of (or names dependant on) the template
       *  parameters, which are specific to the implementation.
      */
      typedef _CharT                                 char_type;
      typedef typename _Traits::int_type             int_type;
      typedef typename _Traits::pos_type             pos_type;
      typedef typename _Traits::off_type             off_type;
      typedef _Traits                                traits_type;
      //@}

      //@{
      /**
       *  These are non-standard types.
      */
      typedef ctype<_CharT>                          __ctype_type;
      typedef num_put<_CharT, ostreambuf_iterator<_CharT, _Traits> >
						     __num_put_type;
      typedef num_get<_CharT, istreambuf_iterator<_CharT, _Traits> >
						     __num_get_type;
      //@}

      // Data members:
    protected:
      basic_ostream<_CharT, _Traits>*                _M_tie;
      mutable char_type                              _M_fill;
      mutable bool                                   _M_fill_init;
      basic_streambuf<_CharT, _Traits>*              _M_streambuf;

      // Cached use_facet<ctype>, which is based on the current locale info.
      const __ctype_type*                            _M_ctype;
      // For ostream.
      const __num_put_type*                          _M_num_put;
      // For istream.
      const __num_get_type*                          _M_num_get;

    public:
      //@{
      /**
       *  @brief  The quick-and-easy status check.
       *
       *  This allows you to write constructs such as
       *  <code>if (!a_stream) ...</code> and <code>while (a_stream) ...</code>
      */
      operator void*() const
      { return this->fail() ? 0 : const_cast<basic_ios*>(this); }

      bool
      operator!() const
      { return this->fail(); }
      //@}

      /**
       *  @brief  Returns the error state of the stream buffer.
       *  @return  A bit pattern (well, isn't everything?)
       *
       *  See std::ios_base::iostate for the possible bit values.  Most
       *  users will call one of the interpreting wrappers, e.g., good().
      */
      iostate
      rdstate() const
      { return _M_streambuf_state; }

      /**
       *  @brief  [Re]sets the error state.
       *  @param  state  The new state flag(s) to set.
       *
       *  See std::ios_base::iostate for the possible bit values.  Most
       *  users will not need to pass an argument.
      */
      void
      clear(iostate __state = goodbit);

      /**
       *  @brief  Sets additional flags in the error state.
       *  @param  state  The additional state flag(s) to set.
       *
       *  See std::ios_base::iostate for the possible bit values.
      */
      void
      setstate(iostate __state)
      { this->clear(this->rdstate() | __state); }

      // Flip the internal state on for the proper state bits, then re
      // throws the propagated exception if bit also set in
      // exceptions().
      void
      _M_setstate(iostate __state)
      {
	// 27.6.1.2.1 Common requirements.
	// Turn this on without causing an ios::failure to be thrown.
	_M_streambuf_state |= __state;
	if (this->exceptions() & __state)
	  __throw_exception_again;
      }

      /**
       *  @brief  Fast error checking.
       *  @return  True if no error flags are set.
       *
       *  A wrapper around rdstate.
      */
      bool
      good() const
      { return this->rdstate() == 0; }

      /**
       *  @brief  Fast error checking.
       *  @return  True if the eofbit is set.
       *
       *  Note that other iostate flags may also be set.
      */
      bool
      eof() const
      { return (this->rdstate() & eofbit) != 0; }

      /**
       *  @brief  Fast error checking.
       *  @return  True if either the badbit or the failbit is set.
       *
       *  Checking the badbit in fail() is historical practice.
       *  Note that other iostate flags may also be set.
      */
      bool
      fail() const
      { return (this->rdstate() & (badbit | failbit)) != 0; }

      /**
       *  @brief  Fast error checking.
       *  @return  True if the badbit is set.
       *
       *  Note that other iostate flags may also be set.
      */
      bool
      bad() const
      { return (this->rdstate() & badbit) != 0; }

      /**
       *  @brief  Throwing exceptions on errors.
       *  @return  The current exceptions mask.
       *
       *  This changes nothing in the stream.  See the one-argument version
       *  of exceptions(iostate) for the meaning of the return value.
      */
      iostate
      exceptions() const
      { return _M_exception; }

      /**
       *  @brief  Throwing exceptions on errors.
       *  @param  except  The new exceptions mask.
       *
       *  By default, error flags are set silently.  You can set an
       *  exceptions mask for each stream; if a bit in the mask becomes set
       *  in the error flags, then an exception of type
       *  std::ios_base::failure is thrown.
       *
       *  If the error flag is already set when the exceptions mask is
       *  added, the exception is immediately thrown.  Try running the
       *  following under GCC 3.1 or later:
       *  @code
       *  #include <iostream>
       *  #include <fstream>
       *  #include <exception>
       *
       *  int main()
       *  {
       *      std::set_terminate (__gnu_cxx::__verbose_terminate_handler);
       *
       *      std::ifstream f ("/etc/motd");
       *
       *      std::cerr << "Setting badbit\n";
       *      f.setstate (std::ios_base::badbit);
       *
       *      std::cerr << "Setting exception mask\n";
       *      f.exceptions (std::ios_base::badbit);
       *  }
       *  @endcode
      */
      void
      exceptions(iostate __except)
      {
        _M_exception = __except;
        this->clear(_M_streambuf_state);
      }

      // Constructor/destructor:
      /**
       *  @brief  Constructor performs initialization.
       *
       *  The parameter is passed by derived streams.
      */
      explicit
      basic_ios(basic_streambuf<_CharT, _Traits>* __sb)
      : ios_base(), _M_tie(0), _M_fill(), _M_fill_init(false), _M_streambuf(0),
	_M_ctype(0), _M_num_put(0), _M_num_get(0)
      { this->init(__sb); }

      /**
       *  @brief  Empty.
       *
       *  The destructor does nothing.  More specifically, it does not
       *  destroy the streambuf held by rdbuf().
      */
      virtual
      ~basic_ios() { }

      // Members:
      /**
       *  @brief  Fetches the current @e tied stream.
       *  @return  A pointer to the tied stream, or NULL if the stream is
       *           not tied.
       *
       *  A stream may be @e tied (or synchronized) to a second output
       *  stream.  When this stream performs any I/O, the tied stream is
       *  first flushed.  For example, @c std::cin is tied to @c std::cout.
      */
      basic_ostream<_CharT, _Traits>*
      tie() const
      { return _M_tie; }

      /**
       *  @brief  Ties this stream to an output stream.
       *  @param  tiestr  The output stream.
       *  @return  The previously tied output stream, or NULL if the stream
       *           was not tied.
       *
       *  This sets up a new tie; see tie() for more.
      */
      basic_ostream<_CharT, _Traits>*
      tie(basic_ostream<_CharT, _Traits>* __tiestr)
      {
        basic_ostream<_CharT, _Traits>* __old = _M_tie;
        _M_tie = __tiestr;
        return __old;
      }

      /**
       *  @brief  Accessing the underlying buffer.
       *  @return  The current stream buffer.
       *
       *  This does not change the state of the stream.
      */
      basic_streambuf<_CharT, _Traits>*
      rdbuf() const
      { return _M_streambuf; }

      /**
       *  @brief  Changing the underlying buffer.
       *  @param  sb  The new stream buffer.
       *  @return  The previous stream buffer.
       *
       *  Associates a new buffer with the current stream, and clears the
       *  error state.
       *
       *  Due to historical accidents which the LWG refuses to correct, the
       *  I/O library suffers from a design error:  this function is hidden
       *  in derived classes by overrides of the zero-argument @c rdbuf(),
       *  which is non-virtual for hysterical raisins.  As a result, you
       *  must use explicit qualifications to access this function via any
       *  derived class.  For example:
       *
       *  @code
       *  std::fstream     foo;         // or some other derived type
       *  std::streambuf*  p = .....;
       *
       *  foo.ios::rdbuf(p);            // ios == basic_ios<char>
       *  @endcode
      */
      basic_streambuf<_CharT, _Traits>*
      rdbuf(basic_streambuf<_CharT, _Traits>* __sb);

      /**
       *  @brief  Copies fields of __rhs into this.
       *  @param  __rhs  The source values for the copies.
       *  @return  Reference to this object.
       *
       *  All fields of __rhs are copied into this object except that rdbuf()
       *  and rdstate() remain unchanged.  All values in the pword and iword
       *  arrays are copied.  Before copying, each callback is invoked with
       *  erase_event.  After copying, each (new) callback is invoked with
       *  copyfmt_event.  The final step is to copy exceptions().
      */
      basic_ios&
      copyfmt(const basic_ios& __rhs);

      /**
       *  @brief  Retrieves the @a empty character.
       *  @return  The current fill character.
       *
       *  It defaults to a space (' ') in the current locale.
      */
      char_type
      fill() const
      {
	if (!_M_fill_init)
	  {
	    _M_fill = this->widen(' ');
	    _M_fill_init = true;
	  }
	return _M_fill;
      }

      /**
       *  @brief  Sets a new @a empty character.
       *  @param  ch  The new character.
       *  @return  The previous fill character.
       *
       *  The fill character is used to fill out space when P+ characters
       *  have been requested (e.g., via setw), Q characters are actually
       *  used, and Q<P.  It defaults to a space (' ') in the current locale.
      */
      char_type
      fill(char_type __ch)
      {
	char_type __old = this->fill();
	_M_fill = __ch;
	return __old;
      }

      // Locales:
      /**
       *  @brief  Moves to a new locale.
       *  @param  loc  The new locale.
       *  @return  The previous locale.
       *
       *  Calls @c ios_base::imbue(loc), and if a stream buffer is associated
       *  with this stream, calls that buffer's @c pubimbue(loc).
       *
       *  Additional l10n notes are at
       *  http://gcc.gnu.org/onlinedocs/libstdc++/manual/localization.html
      */
      locale
      imbue(const locale& __loc);

      /**
       *  @brief  Squeezes characters.
       *  @param  c  The character to narrow.
       *  @param  dfault  The character to narrow.
       *  @return  The narrowed character.
       *
       *  Maps a character of @c char_type to a character of @c char,
       *  if possible.
       *
       *  Returns the result of
       *  @code
       *    std::use_facet<ctype<char_type> >(getloc()).narrow(c,dfault)
       *  @endcode
       *
       *  Additional l10n notes are at
       *  http://gcc.gnu.org/onlinedocs/libstdc++/manual/localization.html
      */
      char
      narrow(char_type __c, char __dfault) const
      { return __check_facet(_M_ctype).narrow(__c, __dfault); }

      /**
       *  @brief  Widens characters.
       *  @param  c  The character to widen.
       *  @return  The widened character.
       *
       *  Maps a character of @c char to a character of @c char_type.
       *
       *  Returns the result of
       *  @code
       *    std::use_facet<ctype<char_type> >(getloc()).widen(c)
       *  @endcode
       *
       *  Additional l10n notes are at
       *  http://gcc.gnu.org/onlinedocs/libstdc++/manual/localization.html
      */
      char_type
      widen(char __c) const
      { return __check_facet(_M_ctype).widen(__c); }

    protected:
      // 27.4.5.1  basic_ios constructors
      /**
       *  @brief  Empty.
       *
       *  The default constructor does nothing and is not normally
       *  accessible to users.
      */
      basic_ios()
      : ios_base(), _M_tie(0), _M_fill(char_type()), _M_fill_init(false), 
	_M_streambuf(0), _M_ctype(0), _M_num_put(0), _M_num_get(0)
      { }

      /**
       *  @brief  All setup is performed here.
       *
       *  This is called from the public constructor.  It is not virtual and
       *  cannot be redefined.
      */
      void
      init(basic_streambuf<_CharT, _Traits>* __sb);

      void
      _M_cache_locale(const locale& __loc);
    };

_GLIBCXX_END_NAMESPACE_VERSION
} // namespace

#include <bits/basic_ios.tcc>

#endif /* _BASIC_IOS_H */