1 // Streambuf iterators
2
3 // Copyright (C) 1997-2022 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
_GLIBCXX_VISIBILITY(default)38 namespace std _GLIBCXX_VISIBILITY(default)
39 {
40 _GLIBCXX_BEGIN_NAMESPACE_VERSION
41
42 /**
43 * @addtogroup iterators
44 * @{
45 */
46
47 // Ignore warnings about std::iterator.
48 #pragma GCC diagnostic push
49 #pragma GCC diagnostic ignored "-Wdeprecated-declarations"
50 // 24.5.3 Template class istreambuf_iterator
51 /// Provides input iterator semantics for streambufs.
52 template<typename _CharT, typename _Traits>
53 class istreambuf_iterator
54 : public iterator<input_iterator_tag, _CharT, typename _Traits::off_type,
55 _CharT*, _CharT>
56 {
57 public:
58 // Types:
59 ///@{
60 /// Public typedefs
61 #if __cplusplus < 201103L
62 typedef _CharT& reference; // Changed to _CharT by LWG 445
63 #elif __cplusplus > 201703L
64 // _GLIBCXX_RESOLVE_LIB_DEFECTS
65 // 3188. istreambuf_iterator::pointer should not be unspecified
66 using pointer = void;
67 #endif
68
69 typedef _CharT char_type;
70 typedef _Traits traits_type;
71 typedef typename _Traits::int_type int_type;
72 typedef basic_streambuf<_CharT, _Traits> streambuf_type;
73 typedef basic_istream<_CharT, _Traits> istream_type;
74 ///@}
75
76 template<typename _CharT2>
77 friend typename __gnu_cxx::__enable_if<__is_char<_CharT2>::__value,
78 ostreambuf_iterator<_CharT2> >::__type
79 copy(istreambuf_iterator<_CharT2>, istreambuf_iterator<_CharT2>,
80 ostreambuf_iterator<_CharT2>);
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>,
86 istreambuf_iterator<_CharT2>, _CharT2*);
87
88 template<typename _CharT2, typename _Size>
89 friend typename __gnu_cxx::__enable_if<__is_char<_CharT2>::__value,
90 _CharT2*>::__type
91 __copy_n_a(istreambuf_iterator<_CharT2>, _Size, _CharT2*, bool);
92
93 template<typename _CharT2>
94 friend typename __gnu_cxx::__enable_if<__is_char<_CharT2>::__value,
95 istreambuf_iterator<_CharT2> >::__type
96 find(istreambuf_iterator<_CharT2>, istreambuf_iterator<_CharT2>,
97 const _CharT2&);
98
99 template<typename _CharT2, typename _Distance>
100 friend typename __gnu_cxx::__enable_if<__is_char<_CharT2>::__value,
101 void>::__type
102 advance(istreambuf_iterator<_CharT2>&, _Distance);
103
104 private:
105 // 24.5.3 istreambuf_iterator
106 // p 1
107 // If the end of stream is reached (streambuf_type::sgetc()
108 // returns traits_type::eof()), the iterator becomes equal to
109 // the "end of stream" iterator value.
110 // NB: This implementation assumes the "end of stream" value
111 // is EOF, or -1.
112 mutable streambuf_type* _M_sbuf;
113 int_type _M_c;
114
115 public:
116 /// Construct end of input stream iterator.
117 _GLIBCXX_CONSTEXPR istreambuf_iterator() _GLIBCXX_USE_NOEXCEPT
118 : _M_sbuf(0), _M_c(traits_type::eof()) { }
119
120 #if __cplusplus > 201703L && __cpp_lib_concepts
121 constexpr istreambuf_iterator(default_sentinel_t) noexcept
122 : istreambuf_iterator() { }
123 #endif
124
125 #if __cplusplus >= 201103L
126 istreambuf_iterator(const istreambuf_iterator&) noexcept = default;
127
128 ~istreambuf_iterator() = default;
129 #endif
130
131 /// Construct start of input stream iterator.
132 istreambuf_iterator(istream_type& __s) _GLIBCXX_USE_NOEXCEPT
133 : _M_sbuf(__s.rdbuf()), _M_c(traits_type::eof()) { }
134
135 /// Construct start of streambuf iterator.
136 istreambuf_iterator(streambuf_type* __s) _GLIBCXX_USE_NOEXCEPT
137 : _M_sbuf(__s), _M_c(traits_type::eof()) { }
138
139 #if __cplusplus >= 201103L
140 istreambuf_iterator&
141 operator=(const istreambuf_iterator&) noexcept = default;
142 #endif
143
144 /// Return the current character pointed to by iterator. This returns
145 /// streambuf.sgetc(). It cannot be assigned. NB: The result of
146 /// operator*() on an end of stream is undefined.
147 _GLIBCXX_NODISCARD
148 char_type
149 operator*() const
150 {
151 int_type __c = _M_get();
152
153 #ifdef _GLIBCXX_DEBUG_PEDANTIC
154 // Dereferencing a past-the-end istreambuf_iterator is a
155 // libstdc++ extension
156 __glibcxx_requires_cond(!_S_is_eof(__c),
157 _M_message(__gnu_debug::__msg_deref_istreambuf)
158 ._M_iterator(*this));
159 #endif
160 return traits_type::to_char_type(__c);
161 }
162
163 /// Advance the iterator. Calls streambuf.sbumpc().
164 istreambuf_iterator&
165 operator++()
166 {
167 __glibcxx_requires_cond(_M_sbuf &&
168 (!_S_is_eof(_M_c) || !_S_is_eof(_M_sbuf->sgetc())),
169 _M_message(__gnu_debug::__msg_inc_istreambuf)
170 ._M_iterator(*this));
171
172 _M_sbuf->sbumpc();
173 _M_c = traits_type::eof();
174 return *this;
175 }
176
177 /// Advance the iterator. Calls streambuf.sbumpc().
178 istreambuf_iterator
179 operator++(int)
180 {
181 __glibcxx_requires_cond(_M_sbuf &&
182 (!_S_is_eof(_M_c) || !_S_is_eof(_M_sbuf->sgetc())),
183 _M_message(__gnu_debug::__msg_inc_istreambuf)
184 ._M_iterator(*this));
185
186 istreambuf_iterator __old = *this;
187 __old._M_c = _M_sbuf->sbumpc();
188 _M_c = traits_type::eof();
189 return __old;
190 }
191
192 // _GLIBCXX_RESOLVE_LIB_DEFECTS
193 // 110 istreambuf_iterator::equal not const
194 // NB: there is also number 111 (NAD) relevant to this function.
195 /// Return true both iterators are end or both are not end.
196 _GLIBCXX_NODISCARD
197 bool
198 equal(const istreambuf_iterator& __b) const
199 { return _M_at_eof() == __b._M_at_eof(); }
200
201 private:
202 int_type
203 _M_get() const
204 {
205 int_type __ret = _M_c;
206 if (_M_sbuf && _S_is_eof(__ret) && _S_is_eof(__ret = _M_sbuf->sgetc()))
207 _M_sbuf = 0;
208 return __ret;
209 }
210
211 bool
212 _M_at_eof() const
213 { return _S_is_eof(_M_get()); }
214
215 static bool
216 _S_is_eof(int_type __c)
217 {
218 const int_type __eof = traits_type::eof();
219 return traits_type::eq_int_type(__c, __eof);
220 }
221
222 #if __cplusplus > 201703L && __cpp_lib_concepts
223 [[nodiscard]]
224 friend bool
225 operator==(const istreambuf_iterator& __i, default_sentinel_t __s)
226 { return __i._M_at_eof(); }
227 #endif
228 };
229
230 template<typename _CharT, typename _Traits>
231 _GLIBCXX_NODISCARD
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 #if __cpp_impl_three_way_comparison < 201907L
238 template<typename _CharT, typename _Traits>
239 _GLIBCXX_NODISCARD
240 inline bool
241 operator!=(const istreambuf_iterator<_CharT, _Traits>& __a,
242 const istreambuf_iterator<_CharT, _Traits>& __b)
243 { return !__a.equal(__b); }
244 #endif
245
246 /// Provides output iterator semantics for streambufs.
247 template<typename _CharT, typename _Traits>
248 class ostreambuf_iterator
249 : public iterator<output_iterator_tag, void, void, void, void>
250 {
251 public:
252 // Types:
253 ///@{
254 /// Public typedefs
255 #if __cplusplus > 201703L
256 using difference_type = ptrdiff_t;
257 #endif
258 typedef _CharT char_type;
259 typedef _Traits traits_type;
260 typedef basic_streambuf<_CharT, _Traits> streambuf_type;
261 typedef basic_ostream<_CharT, _Traits> ostream_type;
262 ///@}
263
264 template<typename _CharT2>
265 friend typename __gnu_cxx::__enable_if<__is_char<_CharT2>::__value,
266 ostreambuf_iterator<_CharT2> >::__type
267 copy(istreambuf_iterator<_CharT2>, istreambuf_iterator<_CharT2>,
268 ostreambuf_iterator<_CharT2>);
269
270 private:
271 streambuf_type* _M_sbuf;
272 bool _M_failed;
273
274 public:
275
276 #if __cplusplus > 201703L
277 constexpr
278 ostreambuf_iterator() noexcept
279 : _M_sbuf(nullptr), _M_failed(true) { }
280 #endif
281
282 /// Construct output iterator from ostream.
283 ostreambuf_iterator(ostream_type& __s) _GLIBCXX_USE_NOEXCEPT
284 : _M_sbuf(__s.rdbuf()), _M_failed(!_M_sbuf) { }
285
286 /// Construct output iterator from streambuf.
287 ostreambuf_iterator(streambuf_type* __s) _GLIBCXX_USE_NOEXCEPT
288 : _M_sbuf(__s), _M_failed(!_M_sbuf) { }
289
290 /// Write character to streambuf. Calls streambuf.sputc().
291 ostreambuf_iterator&
292 operator=(_CharT __c)
293 {
294 if (!_M_failed &&
295 _Traits::eq_int_type(_M_sbuf->sputc(__c), _Traits::eof()))
296 _M_failed = true;
297 return *this;
298 }
299
300 /// Return *this.
301 _GLIBCXX_NODISCARD
302 ostreambuf_iterator&
303 operator*()
304 { return *this; }
305
306 /// Return *this.
307 ostreambuf_iterator&
308 operator++(int)
309 { return *this; }
310
311 /// Return *this.
312 ostreambuf_iterator&
313 operator++()
314 { return *this; }
315
316 /// Return true if previous operator=() failed.
317 _GLIBCXX_NODISCARD
318 bool
319 failed() const _GLIBCXX_USE_NOEXCEPT
320 { return _M_failed; }
321
322 ostreambuf_iterator&
323 _M_put(const _CharT* __ws, streamsize __len)
324 {
325 if (__builtin_expect(!_M_failed, true)
326 && __builtin_expect(this->_M_sbuf->sputn(__ws, __len) != __len,
327 false))
328 _M_failed = true;
329 return *this;
330 }
331 };
332 #pragma GCC diagnostic pop
333
334 // Overloads for streambuf iterators.
335 template<typename _CharT>
336 typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
337 ostreambuf_iterator<_CharT> >::__type
338 copy(istreambuf_iterator<_CharT> __first,
339 istreambuf_iterator<_CharT> __last,
340 ostreambuf_iterator<_CharT> __result)
341 {
342 if (__first._M_sbuf && !__last._M_sbuf && !__result._M_failed)
343 {
344 bool __ineof;
345 __copy_streambufs_eof(__first._M_sbuf, __result._M_sbuf, __ineof);
346 if (!__ineof)
347 __result._M_failed = true;
348 }
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(_CharT* __first, _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 ostreambuf_iterator<_CharT> >::__type
367 __copy_move_a2(const _CharT* __first, const _CharT* __last,
368 ostreambuf_iterator<_CharT> __result)
369 {
370 const streamsize __num = __last - __first;
371 if (__num > 0)
372 __result._M_put(__first, __num);
373 return __result;
374 }
375
376 template<bool _IsMove, typename _CharT>
377 typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
378 _CharT*>::__type
379 __copy_move_a2(istreambuf_iterator<_CharT> __first,
380 istreambuf_iterator<_CharT> __last, _CharT* __result)
381 {
382 typedef istreambuf_iterator<_CharT> __is_iterator_type;
383 typedef typename __is_iterator_type::traits_type traits_type;
384 typedef typename __is_iterator_type::streambuf_type streambuf_type;
385 typedef typename traits_type::int_type int_type;
386
387 if (__first._M_sbuf && !__last._M_sbuf)
388 {
389 streambuf_type* __sb = __first._M_sbuf;
390 int_type __c = __sb->sgetc();
391 while (!traits_type::eq_int_type(__c, traits_type::eof()))
392 {
393 const streamsize __n = __sb->egptr() - __sb->gptr();
394 if (__n > 1)
395 {
396 traits_type::copy(__result, __sb->gptr(), __n);
397 __sb->__safe_gbump(__n);
398 __result += __n;
399 __c = __sb->underflow();
400 }
401 else
402 {
403 *__result++ = traits_type::to_char_type(__c);
404 __c = __sb->snextc();
405 }
406 }
407 }
408 return __result;
409 }
410
411 template<typename _CharT, typename _Size>
412 typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
413 _CharT*>::__type
414 __copy_n_a(istreambuf_iterator<_CharT> __it, _Size __n, _CharT* __result,
415 bool __strict __attribute__((__unused__)))
416 {
417 if (__n == 0)
418 return __result;
419
420 __glibcxx_requires_cond(__it._M_sbuf,
421 _M_message(__gnu_debug::__msg_inc_istreambuf)
422 ._M_iterator(__it));
423 _CharT* __beg = __result;
424 __result += __it._M_sbuf->sgetn(__beg, __n);
425 __glibcxx_requires_cond(!__strict || __result - __beg == __n,
426 _M_message(__gnu_debug::__msg_inc_istreambuf)
427 ._M_iterator(__it));
428 return __result;
429 }
430
431 template<typename _CharT>
432 typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
433 istreambuf_iterator<_CharT> >::__type
434 find(istreambuf_iterator<_CharT> __first,
435 istreambuf_iterator<_CharT> __last, const _CharT& __val)
436 {
437 typedef istreambuf_iterator<_CharT> __is_iterator_type;
438 typedef typename __is_iterator_type::traits_type traits_type;
439 typedef typename __is_iterator_type::streambuf_type streambuf_type;
440 typedef typename traits_type::int_type int_type;
441 const int_type __eof = traits_type::eof();
442
443 if (__first._M_sbuf && !__last._M_sbuf)
444 {
445 const int_type __ival = traits_type::to_int_type(__val);
446 streambuf_type* __sb = __first._M_sbuf;
447 int_type __c = __sb->sgetc();
448 while (!traits_type::eq_int_type(__c, __eof)
449 && !traits_type::eq_int_type(__c, __ival))
450 {
451 streamsize __n = __sb->egptr() - __sb->gptr();
452 if (__n > 1)
453 {
454 const _CharT* __p = traits_type::find(__sb->gptr(),
455 __n, __val);
456 if (__p)
457 __n = __p - __sb->gptr();
458 __sb->__safe_gbump(__n);
459 __c = __sb->sgetc();
460 }
461 else
462 __c = __sb->snextc();
463 }
464
465 __first._M_c = __eof;
466 }
467
468 return __first;
469 }
470
471 template<typename _CharT, typename _Distance>
472 typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
473 void>::__type
474 advance(istreambuf_iterator<_CharT>& __i, _Distance __n)
475 {
476 if (__n == 0)
477 return;
478
479 __glibcxx_assert(__n > 0);
480 __glibcxx_requires_cond(!__i._M_at_eof(),
481 _M_message(__gnu_debug::__msg_inc_istreambuf)
482 ._M_iterator(__i));
483
484 typedef istreambuf_iterator<_CharT> __is_iterator_type;
485 typedef typename __is_iterator_type::traits_type traits_type;
486 typedef typename __is_iterator_type::streambuf_type streambuf_type;
487 typedef typename traits_type::int_type int_type;
488 const int_type __eof = traits_type::eof();
489
490 streambuf_type* __sb = __i._M_sbuf;
491 while (__n > 0)
492 {
493 streamsize __size = __sb->egptr() - __sb->gptr();
494 if (__size > __n)
495 {
496 __sb->__safe_gbump(__n);
497 break;
498 }
499
500 __sb->__safe_gbump(__size);
501 __n -= __size;
502 if (traits_type::eq_int_type(__sb->underflow(), __eof))
503 {
504 __glibcxx_requires_cond(__n == 0,
505 _M_message(__gnu_debug::__msg_inc_istreambuf)
506 ._M_iterator(__i));
507 break;
508 }
509 }
510
511 __i._M_c = __eof;
512 }
513
514 /// @} group iterators
515
516 _GLIBCXX_END_NAMESPACE_VERSION
517 } // namespace
518
519 #endif
520