1 // Streambuf iterators
2
3 // Copyright (C) 1997-2021 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 // 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*, _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;
69 typedef basic_streambuf<_CharT, _Traits> streambuf_type;
70 typedef basic_istream<_CharT, _Traits> istream_type;
71 ///@}
72
73 template<typename _CharT2>
74 friend typename __gnu_cxx::__enable_if<__is_char<_CharT2>::__value,
75 ostreambuf_iterator<_CharT2> >::__type
76 copy(istreambuf_iterator<_CharT2>, istreambuf_iterator<_CharT2>,
77 ostreambuf_iterator<_CharT2>);
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>,
83 istreambuf_iterator<_CharT2>, _CharT2*);
84
85 template<typename _CharT2, typename _Size>
86 friend typename __gnu_cxx::__enable_if<__is_char<_CharT2>::__value,
87 _CharT2*>::__type
88 __copy_n_a(istreambuf_iterator<_CharT2>, _Size, _CharT2*, bool);
89
90 template<typename _CharT2>
91 friend typename __gnu_cxx::__enable_if<__is_char<_CharT2>::__value,
92 istreambuf_iterator<_CharT2> >::__type
93 find(istreambuf_iterator<_CharT2>, istreambuf_iterator<_CharT2>,
94 const _CharT2&);
95
96 template<typename _CharT2, typename _Distance>
97 friend typename __gnu_cxx::__enable_if<__is_char<_CharT2>::__value,
98 void>::__type
99 advance(istreambuf_iterator<_CharT2>&, _Distance);
100
101 private:
102 // 24.5.3 istreambuf_iterator
103 // p 1
104 // If the end of stream is reached (streambuf_type::sgetc()
105 // returns traits_type::eof()), the iterator becomes equal to
106 // the "end of stream" iterator value.
107 // NB: This implementation assumes the "end of stream" value
108 // is EOF, or -1.
109 mutable streambuf_type* _M_sbuf;
110 int_type _M_c;
111
112 public:
113 /// Construct end of input stream iterator.
114 _GLIBCXX_CONSTEXPR istreambuf_iterator() _GLIBCXX_USE_NOEXCEPT
115 : _M_sbuf(0), _M_c(traits_type::eof()) { }
116
117 #if __cplusplus > 201703L && __cpp_lib_concepts
118 constexpr istreambuf_iterator(default_sentinel_t) noexcept
119 : istreambuf_iterator() { }
120 #endif
121
122 #if __cplusplus >= 201103L
123 istreambuf_iterator(const istreambuf_iterator&) noexcept = default;
124
125 ~istreambuf_iterator() = default;
126 #endif
127
128 /// Construct start of input stream iterator.
129 istreambuf_iterator(istream_type& __s) _GLIBCXX_USE_NOEXCEPT
130 : _M_sbuf(__s.rdbuf()), _M_c(traits_type::eof()) { }
131
132 /// Construct start of streambuf iterator.
133 istreambuf_iterator(streambuf_type* __s) _GLIBCXX_USE_NOEXCEPT
134 : _M_sbuf(__s), _M_c(traits_type::eof()) { }
135
136 #if __cplusplus >= 201103L
137 istreambuf_iterator&
138 operator=(const istreambuf_iterator&) noexcept = default;
139 #endif
140
141 /// Return the current character pointed to by iterator. This returns
142 /// streambuf.sgetc(). It cannot be assigned. NB: The result of
143 /// operator*() on an end of stream is undefined.
144 char_type
145 operator*() const
146 {
147 int_type __c = _M_get();
148
149 #ifdef _GLIBCXX_DEBUG_PEDANTIC
150 // Dereferencing a past-the-end istreambuf_iterator is a
151 // libstdc++ extension
152 __glibcxx_requires_cond(!_S_is_eof(__c),
153 _M_message(__gnu_debug::__msg_deref_istreambuf)
154 ._M_iterator(*this));
155 #endif
156 return traits_type::to_char_type(__c);
157 }
158
159 /// Advance the iterator. Calls streambuf.sbumpc().
160 istreambuf_iterator&
161 operator++()
162 {
163 __glibcxx_requires_cond(_M_sbuf &&
164 (!_S_is_eof(_M_c) || !_S_is_eof(_M_sbuf->sgetc())),
165 _M_message(__gnu_debug::__msg_inc_istreambuf)
166 ._M_iterator(*this));
167
168 _M_sbuf->sbumpc();
169 _M_c = traits_type::eof();
170 return *this;
171 }
172
173 /// Advance the iterator. Calls streambuf.sbumpc().
174 istreambuf_iterator
175 operator++(int)
176 {
177 __glibcxx_requires_cond(_M_sbuf &&
178 (!_S_is_eof(_M_c) || !_S_is_eof(_M_sbuf->sgetc())),
179 _M_message(__gnu_debug::__msg_inc_istreambuf)
180 ._M_iterator(*this));
181
182 istreambuf_iterator __old = *this;
183 __old._M_c = _M_sbuf->sbumpc();
184 _M_c = traits_type::eof();
185 return __old;
186 }
187
188 // _GLIBCXX_RESOLVE_LIB_DEFECTS
189 // 110 istreambuf_iterator::equal not const
190 // NB: there is also number 111 (NAD) relevant to this function.
191 /// Return true both iterators are end or both are not end.
192 bool
193 equal(const istreambuf_iterator& __b) const
194 { return _M_at_eof() == __b._M_at_eof(); }
195
196 private:
197 int_type
198 _M_get() const
199 {
200 int_type __ret = _M_c;
201 if (_M_sbuf && _S_is_eof(__ret) && _S_is_eof(__ret = _M_sbuf->sgetc()))
202 _M_sbuf = 0;
203 return __ret;
204 }
205
206 bool
207 _M_at_eof() const
208 { return _S_is_eof(_M_get()); }
209
210 static bool
211 _S_is_eof(int_type __c)
212 {
213 const int_type __eof = traits_type::eof();
214 return traits_type::eq_int_type(__c, __eof);
215 }
216
217 #if __cplusplus > 201703L && __cpp_lib_concepts
218 friend bool
219 operator==(const istreambuf_iterator& __i, default_sentinel_t __s)
220 { return __i._M_at_eof(); }
221 #endif
222 };
223
224 template<typename _CharT, typename _Traits>
225 inline bool
226 operator==(const istreambuf_iterator<_CharT, _Traits>& __a,
227 const istreambuf_iterator<_CharT, _Traits>& __b)
228 { return __a.equal(__b); }
229
230 template<typename _CharT, typename _Traits>
231 inline bool
232 operator!=(const istreambuf_iterator<_CharT, _Traits>& __a,
233 const istreambuf_iterator<_CharT, _Traits>& __b)
234 { return !__a.equal(__b); }
235
236 /// Provides output iterator semantics for streambufs.
237 template<typename _CharT, typename _Traits>
238 class ostreambuf_iterator
239 : public iterator<output_iterator_tag, void, void, void, void>
240 {
241 public:
242 // Types:
243 ///@{
244 /// Public typedefs
245 #if __cplusplus > 201703L
246 using difference_type = ptrdiff_t;
247 #endif
248 typedef _CharT char_type;
249 typedef _Traits traits_type;
250 typedef basic_streambuf<_CharT, _Traits> streambuf_type;
251 typedef basic_ostream<_CharT, _Traits> ostream_type;
252 ///@}
253
254 template<typename _CharT2>
255 friend typename __gnu_cxx::__enable_if<__is_char<_CharT2>::__value,
256 ostreambuf_iterator<_CharT2> >::__type
257 copy(istreambuf_iterator<_CharT2>, istreambuf_iterator<_CharT2>,
258 ostreambuf_iterator<_CharT2>);
259
260 private:
261 streambuf_type* _M_sbuf;
262 bool _M_failed;
263
264 public:
265
266 #if __cplusplus > 201703L
267 constexpr
268 ostreambuf_iterator() noexcept
269 : _M_sbuf(nullptr), _M_failed(true) { }
270 #endif
271
272 /// Construct output iterator from ostream.
273 ostreambuf_iterator(ostream_type& __s) _GLIBCXX_USE_NOEXCEPT
274 : _M_sbuf(__s.rdbuf()), _M_failed(!_M_sbuf) { }
275
276 /// Construct output iterator from streambuf.
277 ostreambuf_iterator(streambuf_type* __s) _GLIBCXX_USE_NOEXCEPT
278 : _M_sbuf(__s), _M_failed(!_M_sbuf) { }
279
280 /// Write character to streambuf. Calls streambuf.sputc().
281 ostreambuf_iterator&
282 operator=(_CharT __c)
283 {
284 if (!_M_failed &&
285 _Traits::eq_int_type(_M_sbuf->sputc(__c), _Traits::eof()))
286 _M_failed = true;
287 return *this;
288 }
289
290 /// Return *this.
291 ostreambuf_iterator&
292 operator*()
293 { return *this; }
294
295 /// Return *this.
296 ostreambuf_iterator&
297 operator++(int)
298 { return *this; }
299
300 /// Return *this.
301 ostreambuf_iterator&
302 operator++()
303 { return *this; }
304
305 /// Return true if previous operator=() failed.
306 bool
307 failed() const _GLIBCXX_USE_NOEXCEPT
308 { return _M_failed; }
309
310 ostreambuf_iterator&
311 _M_put(const _CharT* __ws, streamsize __len)
312 {
313 if (__builtin_expect(!_M_failed, true)
314 && __builtin_expect(this->_M_sbuf->sputn(__ws, __len) != __len,
315 false))
316 _M_failed = true;
317 return *this;
318 }
319 };
320
321 // Overloads for streambuf iterators.
322 template<typename _CharT>
323 typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
324 ostreambuf_iterator<_CharT> >::__type
325 copy(istreambuf_iterator<_CharT> __first,
326 istreambuf_iterator<_CharT> __last,
327 ostreambuf_iterator<_CharT> __result)
328 {
329 if (__first._M_sbuf && !__last._M_sbuf && !__result._M_failed)
330 {
331 bool __ineof;
332 __copy_streambufs_eof(__first._M_sbuf, __result._M_sbuf, __ineof);
333 if (!__ineof)
334 __result._M_failed = true;
335 }
336 return __result;
337 }
338
339 template<bool _IsMove, typename _CharT>
340 typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
341 ostreambuf_iterator<_CharT> >::__type
342 __copy_move_a2(_CharT* __first, _CharT* __last,
343 ostreambuf_iterator<_CharT> __result)
344 {
345 const streamsize __num = __last - __first;
346 if (__num > 0)
347 __result._M_put(__first, __num);
348 return __result;
349 }
350
351 template<bool _IsMove, typename _CharT>
352 typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
353 ostreambuf_iterator<_CharT> >::__type
354 __copy_move_a2(const _CharT* __first, const _CharT* __last,
355 ostreambuf_iterator<_CharT> __result)
356 {
357 const streamsize __num = __last - __first;
358 if (__num > 0)
359 __result._M_put(__first, __num);
360 return __result;
361 }
362
363 template<bool _IsMove, typename _CharT>
364 typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
365 _CharT*>::__type
366 __copy_move_a2(istreambuf_iterator<_CharT> __first,
367 istreambuf_iterator<_CharT> __last, _CharT* __result)
368 {
369 typedef istreambuf_iterator<_CharT> __is_iterator_type;
370 typedef typename __is_iterator_type::traits_type traits_type;
371 typedef typename __is_iterator_type::streambuf_type streambuf_type;
372 typedef typename traits_type::int_type int_type;
373
374 if (__first._M_sbuf && !__last._M_sbuf)
375 {
376 streambuf_type* __sb = __first._M_sbuf;
377 int_type __c = __sb->sgetc();
378 while (!traits_type::eq_int_type(__c, traits_type::eof()))
379 {
380 const streamsize __n = __sb->egptr() - __sb->gptr();
381 if (__n > 1)
382 {
383 traits_type::copy(__result, __sb->gptr(), __n);
384 __sb->__safe_gbump(__n);
385 __result += __n;
386 __c = __sb->underflow();
387 }
388 else
389 {
390 *__result++ = traits_type::to_char_type(__c);
391 __c = __sb->snextc();
392 }
393 }
394 }
395 return __result;
396 }
397
398 template<typename _CharT, typename _Size>
399 typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
400 _CharT*>::__type
401 __copy_n_a(istreambuf_iterator<_CharT> __it, _Size __n, _CharT* __result,
402 bool __strict __attribute__((__unused__)))
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(!__strict || __result - __beg == __n,
413 _M_message(__gnu_debug::__msg_inc_istreambuf)
414 ._M_iterator(__it));
415 return __result;
416 }
417
418 template<typename _CharT>
419 typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
420 istreambuf_iterator<_CharT> >::__type
421 find(istreambuf_iterator<_CharT> __first,
422 istreambuf_iterator<_CharT> __last, const _CharT& __val)
423 {
424 typedef istreambuf_iterator<_CharT> __is_iterator_type;
425 typedef typename __is_iterator_type::traits_type traits_type;
426 typedef typename __is_iterator_type::streambuf_type streambuf_type;
427 typedef typename traits_type::int_type int_type;
428 const int_type __eof = traits_type::eof();
429
430 if (__first._M_sbuf && !__last._M_sbuf)
431 {
432 const int_type __ival = traits_type::to_int_type(__val);
433 streambuf_type* __sb = __first._M_sbuf;
434 int_type __c = __sb->sgetc();
435 while (!traits_type::eq_int_type(__c, __eof)
436 && !traits_type::eq_int_type(__c, __ival))
437 {
438 streamsize __n = __sb->egptr() - __sb->gptr();
439 if (__n > 1)
440 {
441 const _CharT* __p = traits_type::find(__sb->gptr(),
442 __n, __val);
443 if (__p)
444 __n = __p - __sb->gptr();
445 __sb->__safe_gbump(__n);
446 __c = __sb->sgetc();
447 }
448 else
449 __c = __sb->snextc();
450 }
451
452 __first._M_c = __eof;
453 }
454
455 return __first;
456 }
457
458 template<typename _CharT, typename _Distance>
459 typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
460 void>::__type
461 advance(istreambuf_iterator<_CharT>& __i, _Distance __n)
462 {
463 if (__n == 0)
464 return;
465
466 __glibcxx_assert(__n > 0);
467 __glibcxx_requires_cond(!__i._M_at_eof(),
468 _M_message(__gnu_debug::__msg_inc_istreambuf)
469 ._M_iterator(__i));
470
471 typedef istreambuf_iterator<_CharT> __is_iterator_type;
472 typedef typename __is_iterator_type::traits_type traits_type;
473 typedef typename __is_iterator_type::streambuf_type streambuf_type;
474 typedef typename traits_type::int_type int_type;
475 const int_type __eof = traits_type::eof();
476
477 streambuf_type* __sb = __i._M_sbuf;
478 while (__n > 0)
479 {
480 streamsize __size = __sb->egptr() - __sb->gptr();
481 if (__size > __n)
482 {
483 __sb->__safe_gbump(__n);
484 break;
485 }
486
487 __sb->__safe_gbump(__size);
488 __n -= __size;
489 if (traits_type::eq_int_type(__sb->underflow(), __eof))
490 {
491 __glibcxx_requires_cond(__n == 0,
492 _M_message(__gnu_debug::__msg_inc_istreambuf)
493 ._M_iterator(__i));
494 break;
495 }
496 }
497
498 __i._M_c = __eof;
499 }
500
501 /// @} group iterators
502
503 _GLIBCXX_END_NAMESPACE_VERSION
504 } // namespace
505
506 #endif
507