libstdc++
streambuf_iterator.h
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1 // Streambuf iterators
2 
3 // Copyright (C) 1997-2019 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/streambuf_iterator.h
26  * This is an internal header file, included by other library headers.
27  * Do not attempt to use it directly. @headername{iterator}
28  */
29 
30 #ifndef _STREAMBUF_ITERATOR_H
31 #define _STREAMBUF_ITERATOR_H 1
32 
33 #pragma GCC system_header
34 
35 #include <streambuf>
36 #include <debug/debug.h>
37 
38 namespace std _GLIBCXX_VISIBILITY(default)
39 {
40 _GLIBCXX_BEGIN_NAMESPACE_VERSION
41 
42  /**
43  * @addtogroup iterators
44  * @{
45  */
46 
47  // 24.5.3 Template class istreambuf_iterator
48  /// Provides input iterator semantics for streambufs.
49  template<typename _CharT, typename _Traits>
50  class istreambuf_iterator
51  : public iterator<input_iterator_tag, _CharT, typename _Traits::off_type,
52  _CharT*,
53 #if __cplusplus >= 201103L
54  // LWG 445.
55  _CharT>
56 #else
57  _CharT&>
58 #endif
59  {
60  public:
61  // Types:
62  //@{
63  /// Public typedefs
64 #if __cplusplus > 201703L
65  // _GLIBCXX_RESOLVE_LIB_DEFECTS
66  // 3188. istreambuf_iterator::pointer should not be unspecified
67  using pointer = void;
68 #endif
69  typedef _CharT char_type;
70  typedef _Traits traits_type;
71  typedef typename _Traits::int_type int_type;
74  //@}
75 
76  template<typename _CharT2>
77  friend typename __gnu_cxx::__enable_if<__is_char<_CharT2>::__value,
81 
82  template<bool _IsMove, typename _CharT2>
83  friend typename __gnu_cxx::__enable_if<__is_char<_CharT2>::__value,
84  _CharT2*>::__type
85  __copy_move_a2(istreambuf_iterator<_CharT2>,
87 
88 #if __cplusplus >= 201103L
89  template<typename _CharT2, typename _Size>
90  friend __enable_if_t<__is_char<_CharT2>::__value, _CharT2*>
91  __copy_n_a(istreambuf_iterator<_CharT2>, _Size, _CharT2*);
92 #endif
93 
94  template<typename _CharT2>
95  friend typename __gnu_cxx::__enable_if<__is_char<_CharT2>::__value,
98  const _CharT2&);
99 
100  template<typename _CharT2, typename _Distance>
101  friend typename __gnu_cxx::__enable_if<__is_char<_CharT2>::__value,
102  void>::__type
103  advance(istreambuf_iterator<_CharT2>&, _Distance);
104 
105  private:
106  // 24.5.3 istreambuf_iterator
107  // p 1
108  // If the end of stream is reached (streambuf_type::sgetc()
109  // returns traits_type::eof()), the iterator becomes equal to
110  // the "end of stream" iterator value.
111  // NB: This implementation assumes the "end of stream" value
112  // is EOF, or -1.
113  mutable streambuf_type* _M_sbuf;
114  int_type _M_c;
115 
116  public:
117  /// Construct end of input stream iterator.
118  _GLIBCXX_CONSTEXPR istreambuf_iterator() _GLIBCXX_USE_NOEXCEPT
119  : _M_sbuf(0), _M_c(traits_type::eof()) { }
120 
121 #if __cplusplus >= 201103L
122  istreambuf_iterator(const istreambuf_iterator&) noexcept = default;
123 
124  ~istreambuf_iterator() = default;
125 #endif
126 
127  /// Construct start of input stream iterator.
128  istreambuf_iterator(istream_type& __s) _GLIBCXX_USE_NOEXCEPT
129  : _M_sbuf(__s.rdbuf()), _M_c(traits_type::eof()) { }
130 
131  /// Construct start of streambuf iterator.
132  istreambuf_iterator(streambuf_type* __s) _GLIBCXX_USE_NOEXCEPT
133  : _M_sbuf(__s), _M_c(traits_type::eof()) { }
134 
135 #if __cplusplus >= 201103L
137  operator=(const istreambuf_iterator&) noexcept = default;
138 #endif
139 
140  /// Return the current character pointed to by iterator. This returns
141  /// streambuf.sgetc(). It cannot be assigned. NB: The result of
142  /// operator*() on an end of stream is undefined.
143  char_type
144  operator*() const
145  {
146  int_type __c = _M_get();
147 
148 #ifdef _GLIBCXX_DEBUG_PEDANTIC
149  // Dereferencing a past-the-end istreambuf_iterator is a
150  // libstdc++ extension
151  __glibcxx_requires_cond(!_S_is_eof(__c),
152  _M_message(__gnu_debug::__msg_deref_istreambuf)
153  ._M_iterator(*this));
154 #endif
155  return traits_type::to_char_type(__c);
156  }
157 
158  /// Advance the iterator. Calls streambuf.sbumpc().
161  {
162  __glibcxx_requires_cond(_M_sbuf &&
163  (!_S_is_eof(_M_c) || !_S_is_eof(_M_sbuf->sgetc())),
164  _M_message(__gnu_debug::__msg_inc_istreambuf)
165  ._M_iterator(*this));
166 
167  _M_sbuf->sbumpc();
168  _M_c = traits_type::eof();
169  return *this;
170  }
171 
172  /// Advance the iterator. Calls streambuf.sbumpc().
175  {
176  __glibcxx_requires_cond(_M_sbuf &&
177  (!_S_is_eof(_M_c) || !_S_is_eof(_M_sbuf->sgetc())),
178  _M_message(__gnu_debug::__msg_inc_istreambuf)
179  ._M_iterator(*this));
180 
181  istreambuf_iterator __old = *this;
182  __old._M_c = _M_sbuf->sbumpc();
183  _M_c = traits_type::eof();
184  return __old;
185  }
186 
187  // _GLIBCXX_RESOLVE_LIB_DEFECTS
188  // 110 istreambuf_iterator::equal not const
189  // NB: there is also number 111 (NAD) relevant to this function.
190  /// Return true both iterators are end or both are not end.
191  bool
192  equal(const istreambuf_iterator& __b) const
193  { return _M_at_eof() == __b._M_at_eof(); }
194 
195  private:
196  int_type
197  _M_get() const
198  {
199  int_type __ret = _M_c;
200  if (_M_sbuf && _S_is_eof(__ret) && _S_is_eof(__ret = _M_sbuf->sgetc()))
201  _M_sbuf = 0;
202  return __ret;
203  }
204 
205  bool
206  _M_at_eof() const
207  { return _S_is_eof(_M_get()); }
208 
209  static bool
210  _S_is_eof(int_type __c)
211  {
212  const int_type __eof = traits_type::eof();
213  return traits_type::eq_int_type(__c, __eof);
214  }
215  };
216 
217  template<typename _CharT, typename _Traits>
218  inline bool
219  operator==(const istreambuf_iterator<_CharT, _Traits>& __a,
220  const istreambuf_iterator<_CharT, _Traits>& __b)
221  { return __a.equal(__b); }
222 
223  template<typename _CharT, typename _Traits>
224  inline bool
225  operator!=(const istreambuf_iterator<_CharT, _Traits>& __a,
226  const istreambuf_iterator<_CharT, _Traits>& __b)
227  { return !__a.equal(__b); }
228 
229  /// Provides output iterator semantics for streambufs.
230  template<typename _CharT, typename _Traits>
231  class ostreambuf_iterator
232  : public iterator<output_iterator_tag, void, void, void, void>
233  {
234  public:
235  // Types:
236  //@{
237  /// Public typedefs
238 #if __cplusplus > 201703L
239  using difference_type = ptrdiff_t;
240 #endif
241  typedef _CharT char_type;
242  typedef _Traits traits_type;
245  //@}
246 
247  template<typename _CharT2>
248  friend typename __gnu_cxx::__enable_if<__is_char<_CharT2>::__value,
252 
253  private:
254  streambuf_type* _M_sbuf;
255  bool _M_failed;
256 
257  public:
258 
259 #if __cplusplus > 201703L
260  constexpr
261  ostreambuf_iterator() noexcept
262  : _M_sbuf(nullptr), _M_failed(true) { }
263 #endif
264 
265  /// Construct output iterator from ostream.
266  ostreambuf_iterator(ostream_type& __s) _GLIBCXX_USE_NOEXCEPT
267  : _M_sbuf(__s.rdbuf()), _M_failed(!_M_sbuf) { }
268 
269  /// Construct output iterator from streambuf.
270  ostreambuf_iterator(streambuf_type* __s) _GLIBCXX_USE_NOEXCEPT
271  : _M_sbuf(__s), _M_failed(!_M_sbuf) { }
272 
273  /// Write character to streambuf. Calls streambuf.sputc().
275  operator=(_CharT __c)
276  {
277  if (!_M_failed &&
278  _Traits::eq_int_type(_M_sbuf->sputc(__c), _Traits::eof()))
279  _M_failed = true;
280  return *this;
281  }
282 
283  /// Return *this.
286  { return *this; }
287 
288  /// Return *this.
291  { return *this; }
292 
293  /// Return *this.
296  { return *this; }
297 
298  /// Return true if previous operator=() failed.
299  bool
300  failed() const _GLIBCXX_USE_NOEXCEPT
301  { return _M_failed; }
302 
304  _M_put(const _CharT* __ws, streamsize __len)
305  {
306  if (__builtin_expect(!_M_failed, true)
307  && __builtin_expect(this->_M_sbuf->sputn(__ws, __len) != __len,
308  false))
309  _M_failed = true;
310  return *this;
311  }
312  };
313 
314  // Overloads for streambuf iterators.
315  template<typename _CharT>
316  typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
317  ostreambuf_iterator<_CharT> >::__type
318  copy(istreambuf_iterator<_CharT> __first,
319  istreambuf_iterator<_CharT> __last,
320  ostreambuf_iterator<_CharT> __result)
321  {
322  if (__first._M_sbuf && !__last._M_sbuf && !__result._M_failed)
323  {
324  bool __ineof;
325  __copy_streambufs_eof(__first._M_sbuf, __result._M_sbuf, __ineof);
326  if (!__ineof)
327  __result._M_failed = true;
328  }
329  return __result;
330  }
331 
332  template<bool _IsMove, typename _CharT>
333  typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
334  ostreambuf_iterator<_CharT> >::__type
335  __copy_move_a2(_CharT* __first, _CharT* __last,
336  ostreambuf_iterator<_CharT> __result)
337  {
338  const streamsize __num = __last - __first;
339  if (__num > 0)
340  __result._M_put(__first, __num);
341  return __result;
342  }
343 
344  template<bool _IsMove, typename _CharT>
345  typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
346  ostreambuf_iterator<_CharT> >::__type
347  __copy_move_a2(const _CharT* __first, const _CharT* __last,
348  ostreambuf_iterator<_CharT> __result)
349  {
350  const streamsize __num = __last - __first;
351  if (__num > 0)
352  __result._M_put(__first, __num);
353  return __result;
354  }
355 
356  template<bool _IsMove, typename _CharT>
357  typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
358  _CharT*>::__type
359  __copy_move_a2(istreambuf_iterator<_CharT> __first,
360  istreambuf_iterator<_CharT> __last, _CharT* __result)
361  {
362  typedef istreambuf_iterator<_CharT> __is_iterator_type;
363  typedef typename __is_iterator_type::traits_type traits_type;
364  typedef typename __is_iterator_type::streambuf_type streambuf_type;
365  typedef typename traits_type::int_type int_type;
366 
367  if (__first._M_sbuf && !__last._M_sbuf)
368  {
369  streambuf_type* __sb = __first._M_sbuf;
370  int_type __c = __sb->sgetc();
371  while (!traits_type::eq_int_type(__c, traits_type::eof()))
372  {
373  const streamsize __n = __sb->egptr() - __sb->gptr();
374  if (__n > 1)
375  {
376  traits_type::copy(__result, __sb->gptr(), __n);
377  __sb->__safe_gbump(__n);
378  __result += __n;
379  __c = __sb->underflow();
380  }
381  else
382  {
383  *__result++ = traits_type::to_char_type(__c);
384  __c = __sb->snextc();
385  }
386  }
387  }
388  return __result;
389  }
390 
391 #if __cplusplus >= 201103L
392  template<typename _CharT, typename _Size>
393  __enable_if_t<__is_char<_CharT>::__value, _CharT*>
394  __copy_n_a(istreambuf_iterator<_CharT> __it, _Size __n, _CharT* __result)
395  {
396  if (__n == 0)
397  return __result;
398 
399  __glibcxx_requires_cond(__it._M_sbuf,
400  _M_message(__gnu_debug::__msg_inc_istreambuf)
401  ._M_iterator(__it));
402  _CharT* __beg = __result;
403  __result += __it._M_sbuf->sgetn(__beg, __n);
404  __glibcxx_requires_cond(__result - __beg == __n,
405  _M_message(__gnu_debug::__msg_inc_istreambuf)
406  ._M_iterator(__it));
407  return __result;
408  }
409 #endif // C++11
410 
411  template<typename _CharT>
412  typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
413  istreambuf_iterator<_CharT> >::__type
414  find(istreambuf_iterator<_CharT> __first,
415  istreambuf_iterator<_CharT> __last, const _CharT& __val)
416  {
417  typedef istreambuf_iterator<_CharT> __is_iterator_type;
418  typedef typename __is_iterator_type::traits_type traits_type;
419  typedef typename __is_iterator_type::streambuf_type streambuf_type;
420  typedef typename traits_type::int_type int_type;
421  const int_type __eof = traits_type::eof();
422 
423  if (__first._M_sbuf && !__last._M_sbuf)
424  {
425  const int_type __ival = traits_type::to_int_type(__val);
426  streambuf_type* __sb = __first._M_sbuf;
427  int_type __c = __sb->sgetc();
428  while (!traits_type::eq_int_type(__c, __eof)
429  && !traits_type::eq_int_type(__c, __ival))
430  {
431  streamsize __n = __sb->egptr() - __sb->gptr();
432  if (__n > 1)
433  {
434  const _CharT* __p = traits_type::find(__sb->gptr(),
435  __n, __val);
436  if (__p)
437  __n = __p - __sb->gptr();
438  __sb->__safe_gbump(__n);
439  __c = __sb->sgetc();
440  }
441  else
442  __c = __sb->snextc();
443  }
444 
445  __first._M_c = __eof;
446  }
447 
448  return __first;
449  }
450 
451  template<typename _CharT, typename _Distance>
452  typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
453  void>::__type
454  advance(istreambuf_iterator<_CharT>& __i, _Distance __n)
455  {
456  if (__n == 0)
457  return;
458 
459  __glibcxx_assert(__n > 0);
460  __glibcxx_requires_cond(!__i._M_at_eof(),
461  _M_message(__gnu_debug::__msg_inc_istreambuf)
462  ._M_iterator(__i));
463 
464  typedef istreambuf_iterator<_CharT> __is_iterator_type;
465  typedef typename __is_iterator_type::traits_type traits_type;
466  typedef typename __is_iterator_type::streambuf_type streambuf_type;
467  typedef typename traits_type::int_type int_type;
468  const int_type __eof = traits_type::eof();
469 
470  streambuf_type* __sb = __i._M_sbuf;
471  while (__n > 0)
472  {
473  streamsize __size = __sb->egptr() - __sb->gptr();
474  if (__size > __n)
475  {
476  __sb->__safe_gbump(__n);
477  break;
478  }
479 
480  __sb->__safe_gbump(__size);
481  __n -= __size;
482  if (traits_type::eq_int_type(__sb->underflow(), __eof))
483  {
484  __glibcxx_requires_cond(__n == 0,
485  _M_message(__gnu_debug::__msg_inc_istreambuf)
486  ._M_iterator(__i));
487  break;
488  }
489  }
490 
491  __i._M_c = __eof;
492  }
493 
494 // @} group iterators
495 
496 _GLIBCXX_END_NAMESPACE_VERSION
497 } // namespace
498 
499 #endif
std::ostreambuf_iterator::failed
bool failed() const noexcept
Return true if previous operator=() failed.
Definition: streambuf_iterator.h:300
std::istreambuf_iterator::istreambuf_iterator
constexpr istreambuf_iterator() noexcept
Construct end of input stream iterator.
Definition: streambuf_iterator.h:118
debug.h
std::basic_streambuf::sputc
int_type sputc(char_type __c)
Entry point for all single-character output functions.
Definition: streambuf:431
std::istreambuf_iterator::char_type
_CharT char_type
Public typedefs.
Definition: streambuf_iterator.h:69
std::ostreambuf_iterator::operator++
ostreambuf_iterator & operator++(int)
Return *this.
Definition: streambuf_iterator.h:290
std::ostreambuf_iterator::operator*
ostreambuf_iterator & operator*()
Return *this.
Definition: streambuf_iterator.h:285
std::ostreambuf_iterator::ostreambuf_iterator
ostreambuf_iterator(streambuf_type *__s) noexcept
Construct output iterator from streambuf.
Definition: streambuf_iterator.h:270
std::iterator< input_iterator_tag, _CharT, _Traits::off_type, _CharT *, _CharT >::pointer
_CharT * pointer
This type represents a pointer-to-value_type.
Definition: stl_iterator_base_types.h:136
std::istreambuf_iterator::operator++
istreambuf_iterator operator++(int)
Advance the iterator. Calls streambuf.sbumpc().
Definition: streambuf_iterator.h:174
std
ISO C++ entities toplevel namespace is std.
std::basic_streambuf::sbumpc
int_type sbumpc()
Getting the next character.
Definition: streambuf:323
std::basic_streambuf::sgetc
int_type sgetc()
Getting the next character.
Definition: streambuf:345
std::basic_ostream
Template class basic_ostream.
Definition: iosfwd:86
std::advance
constexpr void advance(_InputIterator &__i, _Distance __n)
A generalization of pointer arithmetic.
Definition: stl_iterator_base_funcs.h:202
std::basic_streambuf
The actual work of input and output (interface).
Definition: iosfwd:80
std::streamsize
ptrdiff_t streamsize
Integral type for I/O operation counts and buffer sizes.
Definition: postypes.h:98
std::ostreambuf_iterator
Provides output iterator semantics for streambufs.
Definition: iosfwd:128
std::ostreambuf_iterator::operator++
ostreambuf_iterator & operator++()
Return *this.
Definition: streambuf_iterator.h:295
std::ostreambuf_iterator::ostreambuf_iterator
ostreambuf_iterator(ostream_type &__s) noexcept
Construct output iterator from ostream.
Definition: streambuf_iterator.h:266
std::istreambuf_iterator::operator++
istreambuf_iterator & operator++()
Advance the iterator. Calls streambuf.sbumpc().
Definition: streambuf_iterator.h:160
std::istreambuf_iterator::istreambuf_iterator
istreambuf_iterator(istream_type &__s) noexcept
Construct start of input stream iterator.
Definition: streambuf_iterator.h:128
std::basic_streambuf::sputn
streamsize sputn(const char_type *__s, streamsize __n)
Entry point for all single-character output functions.
Definition: streambuf:457
std::istreambuf_iterator
Provides input iterator semantics for streambufs.
Definition: iosfwd:125
std::istreambuf_iterator::equal
bool equal(const istreambuf_iterator &__b) const
Return true both iterators are end or both are not end.
Definition: streambuf_iterator.h:192
std::basic_istream
Template class basic_istream.
Definition: iosfwd:83
streambuf
std::istreambuf_iterator::istreambuf_iterator
istreambuf_iterator(streambuf_type *__s) noexcept
Construct start of streambuf iterator.
Definition: streambuf_iterator.h:132
std::istreambuf_iterator::operator*
char_type operator*() const
Return the current character pointed to by iterator. This returns streambuf.sgetc()....
Definition: streambuf_iterator.h:144
std::ostreambuf_iterator::operator=
ostreambuf_iterator & operator=(_CharT __c)
Write character to streambuf. Calls streambuf.sputc().
Definition: streambuf_iterator.h:275
std::iterator< output_iterator_tag, void, void, void, void >::difference_type
void difference_type
Distance between iterators is represented as this type.
Definition: stl_iterator_base_types.h:134
std::ostreambuf_iterator::char_type
_CharT char_type
Public typedefs.
Definition: streambuf_iterator.h:241