libstdc++
streambuf_iterator.h
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1// Streambuf iterators
2
3// Copyright (C) 1997-2020 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
38namespace 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>
51 : public iterator<input_iterator_tag, _CharT, typename _Traits::off_type,
52 _CharT*, _CharT>
53 {
54 public:
55 // Types:
56 ///@{
57 /// Public typedefs
58#if __cplusplus < 201103L
59 typedef _CharT& reference; // Changed to _CharT by LWG 445
60#elif __cplusplus > 201703L
61 // _GLIBCXX_RESOLVE_LIB_DEFECTS
62 // 3188. istreambuf_iterator::pointer should not be unspecified
63 using pointer = void;
64#endif
65
66 typedef _CharT char_type;
67 typedef _Traits traits_type;
68 typedef typename _Traits::int_type int_type;
71 ///@}
72
73 template<typename _CharT2>
74 friend typename __gnu_cxx::__enable_if<__is_char<_CharT2>::__value,
78
79 template<bool _IsMove, typename _CharT2>
80 friend typename __gnu_cxx::__enable_if<__is_char<_CharT2>::__value,
81 _CharT2*>::__type
82 __copy_move_a2(istreambuf_iterator<_CharT2>,
84
85#if __cplusplus >= 201103L
86 template<typename _CharT2, typename _Size>
88 __copy_n_a(istreambuf_iterator<_CharT2>, _Size, _CharT2*);
89#endif
90
91 template<typename _CharT2>
92 friend typename __gnu_cxx::__enable_if<__is_char<_CharT2>::__value,
95 const _CharT2&);
96
97 template<typename _CharT2, typename _Distance>
98 friend typename __gnu_cxx::__enable_if<__is_char<_CharT2>::__value,
99 void>::__type
101
102 private:
103 // 24.5.3 istreambuf_iterator
104 // p 1
105 // If the end of stream is reached (streambuf_type::sgetc()
106 // returns traits_type::eof()), the iterator becomes equal to
107 // the "end of stream" iterator value.
108 // NB: This implementation assumes the "end of stream" value
109 // is EOF, or -1.
110 mutable streambuf_type* _M_sbuf;
111 int_type _M_c;
112
113 public:
114 /// Construct end of input stream iterator.
117
118#if __cplusplus > 201703L && __cpp_lib_concepts
120 : istreambuf_iterator() { }
121#endif
122
123#if __cplusplus >= 201103L
124 istreambuf_iterator(const istreambuf_iterator&) noexcept = default;
125
126 ~istreambuf_iterator() = default;
127#endif
128
129 /// Construct start of input stream iterator.
131 : _M_sbuf(__s.rdbuf()), _M_c(traits_type::eof()) { }
132
133 /// Construct start of streambuf iterator.
135 : _M_sbuf(__s), _M_c(traits_type::eof()) { }
136
137#if __cplusplus >= 201103L
139 operator=(const istreambuf_iterator&) noexcept = default;
140#endif
141
142 /// Return the current character pointed to by iterator. This returns
143 /// streambuf.sgetc(). It cannot be assigned. NB: The result of
144 /// operator*() on an end of stream is undefined.
146 operator*() const
147 {
148 int_type __c = _M_get();
149
150#ifdef _GLIBCXX_DEBUG_PEDANTIC
151 // Dereferencing a past-the-end istreambuf_iterator is a
152 // libstdc++ extension
153 __glibcxx_requires_cond(!_S_is_eof(__c),
154 _M_message(__gnu_debug::__msg_deref_istreambuf)
155 ._M_iterator(*this));
156#endif
157 return traits_type::to_char_type(__c);
158 }
159
160 /// Advance the iterator. Calls streambuf.sbumpc().
163 {
164 __glibcxx_requires_cond(_M_sbuf &&
165 (!_S_is_eof(_M_c) || !_S_is_eof(_M_sbuf->sgetc())),
166 _M_message(__gnu_debug::__msg_inc_istreambuf)
167 ._M_iterator(*this));
168
169 _M_sbuf->sbumpc();
170 _M_c = traits_type::eof();
171 return *this;
172 }
173
174 /// Advance the iterator. Calls streambuf.sbumpc().
177 {
178 __glibcxx_requires_cond(_M_sbuf &&
179 (!_S_is_eof(_M_c) || !_S_is_eof(_M_sbuf->sgetc())),
180 _M_message(__gnu_debug::__msg_inc_istreambuf)
181 ._M_iterator(*this));
182
184 __old._M_c = _M_sbuf->sbumpc();
185 _M_c = traits_type::eof();
186 return __old;
187 }
188
189 // _GLIBCXX_RESOLVE_LIB_DEFECTS
190 // 110 istreambuf_iterator::equal not const
191 // NB: there is also number 111 (NAD) relevant to this function.
192 /// Return true both iterators are end or both are not end.
193 bool
194 equal(const istreambuf_iterator& __b) const
195 { return _M_at_eof() == __b._M_at_eof(); }
196
197 private:
199 _M_get() const
200 {
201 int_type __ret = _M_c;
202 if (_M_sbuf && _S_is_eof(__ret) && _S_is_eof(__ret = _M_sbuf->sgetc()))
203 _M_sbuf = 0;
204 return __ret;
205 }
206
207 bool
208 _M_at_eof() const
209 { return _S_is_eof(_M_get()); }
210
211 static bool
212 _S_is_eof(int_type __c)
213 {
214 const int_type __eof = traits_type::eof();
215 return traits_type::eq_int_type(__c, __eof);
216 }
217
218#if __cplusplus > 201703L && __cpp_lib_concepts
219 friend bool
220 operator==(const istreambuf_iterator& __i, default_sentinel_t __s)
221 { return __i._M_at_eof(); }
222#endif
223 };
224
225 template<typename _CharT, typename _Traits>
226 inline bool
227 operator==(const istreambuf_iterator<_CharT, _Traits>& __a,
228 const istreambuf_iterator<_CharT, _Traits>& __b)
229 { return __a.equal(__b); }
230
231 template<typename _CharT, typename _Traits>
232 inline bool
233 operator!=(const istreambuf_iterator<_CharT, _Traits>& __a,
234 const istreambuf_iterator<_CharT, _Traits>& __b)
235 { return !__a.equal(__b); }
236
237 /// Provides output iterator semantics for streambufs.
238 template<typename _CharT, typename _Traits>
240 : public iterator<output_iterator_tag, void, void, void, void>
241 {
242 public:
243 // Types:
244 ///@{
245 /// Public typedefs
246#if __cplusplus > 201703L
248#endif
249 typedef _CharT char_type;
250 typedef _Traits traits_type;
253 ///@}
254
255 template<typename _CharT2>
256 friend typename __gnu_cxx::__enable_if<__is_char<_CharT2>::__value,
260
261 private:
262 streambuf_type* _M_sbuf;
263 bool _M_failed;
264
265 public:
266
267#if __cplusplus > 201703L
268 constexpr
270 : _M_sbuf(nullptr), _M_failed(true) { }
271#endif
272
273 /// Construct output iterator from ostream.
275 : _M_sbuf(__s.rdbuf()), _M_failed(!_M_sbuf) { }
276
277 /// Construct output iterator from streambuf.
279 : _M_sbuf(__s), _M_failed(!_M_sbuf) { }
280
281 /// Write character to streambuf. Calls streambuf.sputc().
283 operator=(_CharT __c)
284 {
285 if (!_M_failed &&
286 _Traits::eq_int_type(_M_sbuf->sputc(__c), _Traits::eof()))
287 _M_failed = true;
288 return *this;
289 }
290
291 /// Return *this.
294 { return *this; }
295
296 /// Return *this.
299 { return *this; }
300
301 /// Return *this.
304 { return *this; }
305
306 /// Return true if previous operator=() failed.
307 bool
309 { return _M_failed; }
310
312 _M_put(const _CharT* __ws, streamsize __len)
313 {
314 if (__builtin_expect(!_M_failed, true)
315 && __builtin_expect(this->_M_sbuf->sputn(__ws, __len) != __len,
316 false))
317 _M_failed = true;
318 return *this;
319 }
320 };
321
322 // Overloads for streambuf iterators.
323 template<typename _CharT>
324 typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
325 ostreambuf_iterator<_CharT> >::__type
326 copy(istreambuf_iterator<_CharT> __first,
327 istreambuf_iterator<_CharT> __last,
328 ostreambuf_iterator<_CharT> __result)
329 {
330 if (__first._M_sbuf && !__last._M_sbuf && !__result._M_failed)
331 {
332 bool __ineof;
333 __copy_streambufs_eof(__first._M_sbuf, __result._M_sbuf, __ineof);
334 if (!__ineof)
335 __result._M_failed = true;
336 }
337 return __result;
338 }
339
340 template<bool _IsMove, typename _CharT>
341 typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
342 ostreambuf_iterator<_CharT> >::__type
343 __copy_move_a2(_CharT* __first, _CharT* __last,
344 ostreambuf_iterator<_CharT> __result)
345 {
346 const streamsize __num = __last - __first;
347 if (__num > 0)
348 __result._M_put(__first, __num);
349 return __result;
350 }
351
352 template<bool _IsMove, typename _CharT>
353 typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
354 ostreambuf_iterator<_CharT> >::__type
355 __copy_move_a2(const _CharT* __first, const _CharT* __last,
356 ostreambuf_iterator<_CharT> __result)
357 {
358 const streamsize __num = __last - __first;
359 if (__num > 0)
360 __result._M_put(__first, __num);
361 return __result;
362 }
363
364 template<bool _IsMove, typename _CharT>
365 typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
366 _CharT*>::__type
367 __copy_move_a2(istreambuf_iterator<_CharT> __first,
368 istreambuf_iterator<_CharT> __last, _CharT* __result)
369 {
370 typedef istreambuf_iterator<_CharT> __is_iterator_type;
371 typedef typename __is_iterator_type::traits_type traits_type;
372 typedef typename __is_iterator_type::streambuf_type streambuf_type;
373 typedef typename traits_type::int_type int_type;
374
375 if (__first._M_sbuf && !__last._M_sbuf)
376 {
377 streambuf_type* __sb = __first._M_sbuf;
378 int_type __c = __sb->sgetc();
379 while (!traits_type::eq_int_type(__c, traits_type::eof()))
380 {
381 const streamsize __n = __sb->egptr() - __sb->gptr();
382 if (__n > 1)
383 {
384 traits_type::copy(__result, __sb->gptr(), __n);
385 __sb->__safe_gbump(__n);
386 __result += __n;
387 __c = __sb->underflow();
388 }
389 else
390 {
391 *__result++ = traits_type::to_char_type(__c);
392 __c = __sb->snextc();
393 }
394 }
395 }
396 return __result;
397 }
398
399#if __cplusplus >= 201103L
400 template<typename _CharT, typename _Size>
401 __enable_if_t<__is_char<_CharT>::__value, _CharT*>
402 __copy_n_a(istreambuf_iterator<_CharT> __it, _Size __n, _CharT* __result)
403 {
404 if (__n == 0)
405 return __result;
406
407 __glibcxx_requires_cond(__it._M_sbuf,
408 _M_message(__gnu_debug::__msg_inc_istreambuf)
409 ._M_iterator(__it));
410 _CharT* __beg = __result;
411 __result += __it._M_sbuf->sgetn(__beg, __n);
412 __glibcxx_requires_cond(__result - __beg == __n,
413 _M_message(__gnu_debug::__msg_inc_istreambuf)
414 ._M_iterator(__it));
415 return __result;
416 }
417#endif // C++11
418
419 template<typename _CharT>
420 typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
421 istreambuf_iterator<_CharT> >::__type
422 find(istreambuf_iterator<_CharT> __first,
423 istreambuf_iterator<_CharT> __last, const _CharT& __val)
424 {
425 typedef istreambuf_iterator<_CharT> __is_iterator_type;
426 typedef typename __is_iterator_type::traits_type traits_type;
427 typedef typename __is_iterator_type::streambuf_type streambuf_type;
428 typedef typename traits_type::int_type int_type;
429 const int_type __eof = traits_type::eof();
430
431 if (__first._M_sbuf && !__last._M_sbuf)
432 {
433 const int_type __ival = traits_type::to_int_type(__val);
434 streambuf_type* __sb = __first._M_sbuf;
435 int_type __c = __sb->sgetc();
436 while (!traits_type::eq_int_type(__c, __eof)
437 && !traits_type::eq_int_type(__c, __ival))
438 {
439 streamsize __n = __sb->egptr() - __sb->gptr();
440 if (__n > 1)
441 {
442 const _CharT* __p = traits_type::find(__sb->gptr(),
443 __n, __val);
444 if (__p)
445 __n = __p - __sb->gptr();
446 __sb->__safe_gbump(__n);
447 __c = __sb->sgetc();
448 }
449 else
450 __c = __sb->snextc();
451 }
452
453 __first._M_c = __eof;
454 }
455
456 return __first;
457 }
458
459 template<typename _CharT, typename _Distance>
460 typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
461 void>::__type
462 advance(istreambuf_iterator<_CharT>& __i, _Distance __n)
463 {
464 if (__n == 0)
465 return;
466
467 __glibcxx_assert(__n > 0);
468 __glibcxx_requires_cond(!__i._M_at_eof(),
469 _M_message(__gnu_debug::__msg_inc_istreambuf)
470 ._M_iterator(__i));
471
472 typedef istreambuf_iterator<_CharT> __is_iterator_type;
473 typedef typename __is_iterator_type::traits_type traits_type;
474 typedef typename __is_iterator_type::streambuf_type streambuf_type;
475 typedef typename traits_type::int_type int_type;
476 const int_type __eof = traits_type::eof();
477
478 streambuf_type* __sb = __i._M_sbuf;
479 while (__n > 0)
480 {
481 streamsize __size = __sb->egptr() - __sb->gptr();
482 if (__size > __n)
483 {
484 __sb->__safe_gbump(__n);
485 break;
486 }
487
488 __sb->__safe_gbump(__size);
489 __n -= __size;
490 if (traits_type::eq_int_type(__sb->underflow(), __eof))
491 {
492 __glibcxx_requires_cond(__n == 0,
493 _M_message(__gnu_debug::__msg_inc_istreambuf)
494 ._M_iterator(__i));
495 break;
496 }
497 }
498
499 __i._M_c = __eof;
500 }
501
502/// @} group iterators
503
504_GLIBCXX_END_NAMESPACE_VERSION
505} // namespace
506
507#endif
ISO C++ entities toplevel namespace is std.
ptrdiff_t streamsize
Integral type for I/O operation counts and buffer sizes.
Definition postypes.h:98
constexpr void advance(_InputIterator &__i, _Distance __n)
A generalization of pointer arithmetic.
Provides input iterator semantics for streambufs.
basic_streambuf< _CharT, _Traits > streambuf_type
Public typedefs.
constexpr istreambuf_iterator() noexcept
Construct end of input stream iterator.
basic_istream< _CharT, _Traits > istream_type
Public typedefs.
char_type operator*() const
Return the current character pointed to by iterator. This returns streambuf.sgetc()....
bool equal(const istreambuf_iterator &__b) const
Return true both iterators are end or both are not end.
istreambuf_iterator & operator++()
Advance the iterator. Calls streambuf.sbumpc().
_Traits traits_type
Public typedefs.
istreambuf_iterator(istream_type &__s) noexcept
Construct start of input stream iterator.
istreambuf_iterator operator++(int)
Advance the iterator. Calls streambuf.sbumpc().
_CharT char_type
Public typedefs.
istreambuf_iterator(streambuf_type *__s) noexcept
Construct start of streambuf iterator.
_Traits::int_type int_type
Public typedefs.
Provides output iterator semantics for streambufs.
ostreambuf_iterator & operator++(int)
Return *this.
ostreambuf_iterator & operator++()
Return *this.
bool failed() const noexcept
Return true if previous operator=() failed.
_Traits traits_type
Public typedefs.
ostreambuf_iterator & operator=(_CharT __c)
Write character to streambuf. Calls streambuf.sputc().
ostreambuf_iterator & operator*()
Return *this.
basic_ostream< _CharT, _Traits > ostream_type
Public typedefs.
basic_streambuf< _CharT, _Traits > streambuf_type
Public typedefs.
ostreambuf_iterator(ostream_type &__s) noexcept
Construct output iterator from ostream.
_CharT char_type
Public typedefs.
ostreambuf_iterator(streambuf_type *__s) noexcept
Construct output iterator from streambuf.
Common iterator class.