1 | // Input streams -*- C++ -*- |
2 | |
3 | // Copyright (C) 1997-2024 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 | // |
26 | // ISO C++ 14882: 27.6.1 Input streams |
27 | // |
28 | |
29 | /** @file include/istream |
30 | * This is a Standard C++ Library header. |
31 | */ |
32 | |
33 | #ifndef _GLIBCXX_ISTREAM |
34 | #define _GLIBCXX_ISTREAM 1 |
35 | |
36 | #pragma GCC system_header |
37 | |
38 | #include <bits/requires_hosted.h> // iostreams |
39 | |
40 | #include <ios> |
41 | #include <ostream> |
42 | |
43 | namespace std _GLIBCXX_VISIBILITY(default) |
44 | { |
45 | _GLIBCXX_BEGIN_NAMESPACE_VERSION |
46 | |
47 | /** |
48 | * @brief Template class basic_istream. |
49 | * @ingroup io |
50 | * |
51 | * @tparam _CharT Type of character stream. |
52 | * @tparam _Traits Traits for character type, defaults to |
53 | * char_traits<_CharT>. |
54 | * |
55 | * This is the base class for all input streams. It provides text |
56 | * formatting of all builtin types, and communicates with any class |
57 | * derived from basic_streambuf to do the actual input. |
58 | */ |
59 | template<typename _CharT, typename _Traits> |
60 | class basic_istream : virtual public basic_ios<_CharT, _Traits> |
61 | { |
62 | public: |
63 | // Types (inherited from basic_ios (27.4.4)): |
64 | typedef _CharT char_type; |
65 | typedef typename _Traits::int_type int_type; |
66 | typedef typename _Traits::pos_type pos_type; |
67 | typedef typename _Traits::off_type off_type; |
68 | typedef _Traits traits_type; |
69 | |
70 | // Non-standard Types: |
71 | typedef basic_streambuf<_CharT, _Traits> __streambuf_type; |
72 | typedef basic_ios<_CharT, _Traits> __ios_type; |
73 | typedef basic_istream<_CharT, _Traits> __istream_type; |
74 | typedef num_get<_CharT, istreambuf_iterator<_CharT, _Traits> > |
75 | __num_get_type; |
76 | typedef ctype<_CharT> __ctype_type; |
77 | |
78 | protected: |
79 | // Data Members: |
80 | /** |
81 | * The number of characters extracted in the previous unformatted |
82 | * function; see gcount(). |
83 | */ |
84 | streamsize _M_gcount; |
85 | |
86 | public: |
87 | /** |
88 | * @brief Base constructor. |
89 | * |
90 | * This ctor is almost never called by the user directly, rather from |
91 | * derived classes' initialization lists, which pass a pointer to |
92 | * their own stream buffer. |
93 | */ |
94 | explicit |
95 | basic_istream(__streambuf_type* __sb) |
96 | : _M_gcount(streamsize(0)) |
97 | { this->init(__sb); } |
98 | |
99 | /** |
100 | * @brief Base destructor. |
101 | * |
102 | * This does very little apart from providing a virtual base dtor. |
103 | */ |
104 | virtual |
105 | ~basic_istream() |
106 | { _M_gcount = streamsize(0); } |
107 | |
108 | /// Safe prefix/suffix operations. |
109 | class sentry; |
110 | friend class sentry; |
111 | |
112 | ///@{ |
113 | /** |
114 | * @brief Interface for manipulators. |
115 | * |
116 | * Manipulators such as @c std::ws and @c std::dec use these |
117 | * functions in constructs like |
118 | * <code>std::cin >> std::ws</code>. |
119 | * For more information, see the iomanip header. |
120 | */ |
121 | __istream_type& |
122 | operator>>(__istream_type& (*__pf)(__istream_type&)) |
123 | { return __pf(*this); } |
124 | |
125 | __istream_type& |
126 | operator>>(__ios_type& (*__pf)(__ios_type&)) |
127 | { |
128 | __pf(*this); |
129 | return *this; |
130 | } |
131 | |
132 | __istream_type& |
133 | operator>>(ios_base& (*__pf)(ios_base&)) |
134 | { |
135 | __pf(*this); |
136 | return *this; |
137 | } |
138 | ///@} |
139 | |
140 | ///@{ |
141 | /** |
142 | * @name Extractors |
143 | * |
144 | * All the @c operator>> functions (aka <em>formatted input |
145 | * functions</em>) have some common behavior. Each starts by |
146 | * constructing a temporary object of type std::basic_istream::sentry |
147 | * with the second argument (noskipws) set to false. This has several |
148 | * effects, concluding with the setting of a status flag; see the |
149 | * sentry documentation for more. |
150 | * |
151 | * If the sentry status is good, the function tries to extract |
152 | * whatever data is appropriate for the type of the argument. |
153 | * |
154 | * If an exception is thrown during extraction, ios_base::badbit |
155 | * will be turned on in the stream's error state (without causing an |
156 | * ios_base::failure to be thrown) and the original exception will |
157 | * be rethrown if badbit is set in the exceptions mask. |
158 | */ |
159 | |
160 | ///@{ |
161 | /** |
162 | * @brief Integer arithmetic extractors |
163 | * @param __n A variable of builtin integral type. |
164 | * @return @c *this if successful |
165 | * |
166 | * These functions use the stream's current locale (specifically, the |
167 | * @c num_get facet) to parse the input data. |
168 | */ |
169 | __istream_type& |
170 | operator>>(bool& __n) |
171 | { return _M_extract(__n); } |
172 | |
173 | __istream_type& |
174 | operator>>(short& __n); |
175 | |
176 | __istream_type& |
177 | operator>>(unsigned short& __n) |
178 | { return _M_extract(__n); } |
179 | |
180 | __istream_type& |
181 | operator>>(int& __n); |
182 | |
183 | __istream_type& |
184 | operator>>(unsigned int& __n) |
185 | { return _M_extract(__n); } |
186 | |
187 | __istream_type& |
188 | operator>>(long& __n) |
189 | { return _M_extract(__n); } |
190 | |
191 | __istream_type& |
192 | operator>>(unsigned long& __n) |
193 | { return _M_extract(__n); } |
194 | |
195 | #ifdef _GLIBCXX_USE_LONG_LONG |
196 | __istream_type& |
197 | operator>>(long long& __n) |
198 | { return _M_extract(__n); } |
199 | |
200 | __istream_type& |
201 | operator>>(unsigned long long& __n) |
202 | { return _M_extract(__n); } |
203 | #endif |
204 | ///@} |
205 | |
206 | ///@{ |
207 | /** |
208 | * @brief Floating point arithmetic extractors |
209 | * @param __f A variable of builtin floating point type. |
210 | * @return @c *this if successful |
211 | * |
212 | * These functions use the stream's current locale (specifically, the |
213 | * @c num_get facet) to parse the input data. |
214 | */ |
215 | __istream_type& |
216 | operator>>(float& __f) |
217 | { return _M_extract(__f); } |
218 | |
219 | __istream_type& |
220 | operator>>(double& __f) |
221 | { return _M_extract(__f); } |
222 | |
223 | __istream_type& |
224 | operator>>(long double& __f) |
225 | { return _M_extract(__f); } |
226 | ///@} |
227 | |
228 | #if defined(__STDCPP_FLOAT16_T__) && defined(_GLIBCXX_FLOAT_IS_IEEE_BINARY32) |
229 | __attribute__((__always_inline__)) |
230 | __istream_type& |
231 | operator>>(_Float16& __f) |
232 | { |
233 | float __flt; |
234 | __istream_type& __ret = _M_extract(__flt); |
235 | ios_base::iostate __err = ios_base::goodbit; |
236 | if (__flt < -__FLT16_MAX__) |
237 | { |
238 | __f = -__FLT16_MAX__; |
239 | __err = ios_base::failbit; |
240 | } |
241 | else if (__flt > __FLT16_MAX__) |
242 | { |
243 | __f = __FLT16_MAX__; |
244 | __err = ios_base::failbit; |
245 | } |
246 | else |
247 | __f = static_cast<_Float16>(__flt); |
248 | if (__err) |
249 | this->setstate(__err); |
250 | return __ret; |
251 | } |
252 | #endif |
253 | |
254 | #if defined(__STDCPP_FLOAT32_T__) && defined(_GLIBCXX_FLOAT_IS_IEEE_BINARY32) |
255 | __attribute__((__always_inline__)) |
256 | __istream_type& |
257 | operator>>(_Float32& __f) |
258 | { |
259 | float __flt; |
260 | __istream_type& __ret = _M_extract(__flt); |
261 | __f = static_cast<_Float32> (__flt); |
262 | return __ret; |
263 | } |
264 | #endif |
265 | |
266 | #if defined(__STDCPP_FLOAT64_T__) && defined(_GLIBCXX_DOUBLE_IS_IEEE_BINARY64) |
267 | __attribute__((__always_inline__)) |
268 | __istream_type& |
269 | operator>>(_Float64& __f) |
270 | { |
271 | double __dbl; |
272 | __istream_type& __ret = _M_extract(__dbl); |
273 | __f = static_cast<_Float64> (__dbl); |
274 | return __ret; |
275 | } |
276 | #endif |
277 | |
278 | #if defined(__STDCPP_FLOAT128_T__) && defined(_GLIBCXX_LDOUBLE_IS_IEEE_BINARY128) |
279 | __attribute__((__always_inline__)) |
280 | __istream_type& |
281 | operator>>(_Float128& __f) |
282 | { |
283 | long double __ldbl; |
284 | __istream_type& __ret = _M_extract(__ldbl); |
285 | __f = static_cast<_Float128> (__ldbl); |
286 | return __ret; |
287 | } |
288 | #endif |
289 | |
290 | #if defined(__STDCPP_BFLOAT16_T__) && defined(_GLIBCXX_FLOAT_IS_IEEE_BINARY32) |
291 | __attribute__((__always_inline__)) |
292 | __istream_type& |
293 | operator>>(__gnu_cxx::__bfloat16_t & __f) |
294 | { |
295 | float __flt; |
296 | __istream_type& __ret = _M_extract(__flt); |
297 | ios_base::iostate __err = ios_base::goodbit; |
298 | if (__flt < -__BFLT16_MAX__) |
299 | { |
300 | __f = -__BFLT16_MAX__; |
301 | __err = ios_base::failbit; |
302 | } |
303 | else if (__flt > __BFLT16_MAX__) |
304 | { |
305 | __f = __BFLT16_MAX__; |
306 | __err = ios_base::failbit; |
307 | } |
308 | else |
309 | __f = static_cast<__gnu_cxx::__bfloat16_t>(__flt); |
310 | if (__err) |
311 | this->setstate(__err); |
312 | return __ret; |
313 | } |
314 | #endif |
315 | |
316 | /** |
317 | * @brief Basic arithmetic extractors |
318 | * @param __p A variable of pointer type. |
319 | * @return @c *this if successful |
320 | * |
321 | * These functions use the stream's current locale (specifically, the |
322 | * @c num_get facet) to parse the input data. |
323 | */ |
324 | __istream_type& |
325 | operator>>(void*& __p) |
326 | { return _M_extract(__p); } |
327 | |
328 | /** |
329 | * @brief Extracting into another streambuf. |
330 | * @param __sb A pointer to a streambuf |
331 | * |
332 | * This function behaves like one of the basic arithmetic extractors, |
333 | * in that it also constructs a sentry object and has the same error |
334 | * handling behavior. |
335 | * |
336 | * If @p __sb is NULL, the stream will set failbit in its error state. |
337 | * |
338 | * Characters are extracted from this stream and inserted into the |
339 | * @p __sb streambuf until one of the following occurs: |
340 | * |
341 | * - the input stream reaches end-of-file, |
342 | * - insertion into the output buffer fails (in this case, the |
343 | * character that would have been inserted is not extracted), or |
344 | * - an exception occurs (and in this case is caught) |
345 | * |
346 | * If the function inserts no characters, failbit is set. |
347 | */ |
348 | __istream_type& |
349 | operator>>(__streambuf_type* __sb); |
350 | ///@} |
351 | |
352 | // [27.6.1.3] unformatted input |
353 | /** |
354 | * @brief Character counting |
355 | * @return The number of characters extracted by the previous |
356 | * unformatted input function dispatched for this stream. |
357 | */ |
358 | streamsize |
359 | gcount() const |
360 | { return _M_gcount; } |
361 | |
362 | ///@{ |
363 | /** |
364 | * @name Unformatted Input Functions |
365 | * |
366 | * All the unformatted input functions have some common behavior. |
367 | * Each starts by constructing a temporary object of type |
368 | * std::basic_istream::sentry with the second argument (noskipws) |
369 | * set to true. This has several effects, concluding with the |
370 | * setting of a status flag; see the sentry documentation for more. |
371 | * |
372 | * If the sentry status is good, the function tries to extract |
373 | * whatever data is appropriate for the type of the argument. |
374 | * |
375 | * The number of characters extracted is stored for later retrieval |
376 | * by gcount(). |
377 | * |
378 | * If an exception is thrown during extraction, ios_base::badbit |
379 | * will be turned on in the stream's error state (without causing an |
380 | * ios_base::failure to be thrown) and the original exception will |
381 | * be rethrown if badbit is set in the exceptions mask. |
382 | */ |
383 | |
384 | /** |
385 | * @brief Simple extraction. |
386 | * @return A character, or eof(). |
387 | * |
388 | * Tries to extract a character. If none are available, sets failbit |
389 | * and returns traits::eof(). |
390 | */ |
391 | int_type |
392 | get(); |
393 | |
394 | /** |
395 | * @brief Simple extraction. |
396 | * @param __c The character in which to store data. |
397 | * @return *this |
398 | * |
399 | * Tries to extract a character and store it in @a __c. If none are |
400 | * available, sets failbit and returns traits::eof(). |
401 | * |
402 | * @note This function is not overloaded on signed char and |
403 | * unsigned char. |
404 | */ |
405 | __istream_type& |
406 | get(char_type& __c); |
407 | |
408 | /** |
409 | * @brief Simple multiple-character extraction. |
410 | * @param __s Pointer to an array. |
411 | * @param __n Maximum number of characters to store in @a __s. |
412 | * @param __delim A "stop" character. |
413 | * @return *this |
414 | * |
415 | * Characters are extracted and stored into @a __s until one of the |
416 | * following happens: |
417 | * |
418 | * - @c __n-1 characters are stored |
419 | * - the input sequence reaches EOF |
420 | * - the next character equals @a __delim, in which case the character |
421 | * is not extracted |
422 | * |
423 | * If no characters are stored, failbit is set in the stream's error |
424 | * state. |
425 | * |
426 | * In any case, a null character is stored into the next location in |
427 | * the array. |
428 | * |
429 | * @note This function is not overloaded on signed char and |
430 | * unsigned char. |
431 | */ |
432 | __istream_type& |
433 | get(char_type* __s, streamsize __n, char_type __delim); |
434 | |
435 | /** |
436 | * @brief Simple multiple-character extraction. |
437 | * @param __s Pointer to an array. |
438 | * @param __n Maximum number of characters to store in @a s. |
439 | * @return *this |
440 | * |
441 | * Returns @c get(__s,__n,widen('\\n')). |
442 | */ |
443 | __istream_type& |
444 | get(char_type* __s, streamsize __n) |
445 | { return this->get(__s, __n, this->widen('\n')); } |
446 | |
447 | /** |
448 | * @brief Extraction into another streambuf. |
449 | * @param __sb A streambuf in which to store data. |
450 | * @param __delim A "stop" character. |
451 | * @return *this |
452 | * |
453 | * Characters are extracted and inserted into @a __sb until one of the |
454 | * following happens: |
455 | * |
456 | * - the input sequence reaches EOF |
457 | * - insertion into the output buffer fails (in this case, the |
458 | * character that would have been inserted is not extracted) |
459 | * - the next character equals @a __delim (in this case, the character |
460 | * is not extracted) |
461 | * - an exception occurs (and in this case is caught) |
462 | * |
463 | * If no characters are stored, failbit is set in the stream's error |
464 | * state. |
465 | */ |
466 | __istream_type& |
467 | get(__streambuf_type& __sb, char_type __delim); |
468 | |
469 | /** |
470 | * @brief Extraction into another streambuf. |
471 | * @param __sb A streambuf in which to store data. |
472 | * @return *this |
473 | * |
474 | * Returns @c get(__sb,widen('\\n')). |
475 | */ |
476 | __istream_type& |
477 | get(__streambuf_type& __sb) |
478 | { return this->get(__sb, this->widen('\n')); } |
479 | |
480 | /** |
481 | * @brief String extraction. |
482 | * @param __s A character array in which to store the data. |
483 | * @param __n Maximum number of characters to extract. |
484 | * @param __delim A "stop" character. |
485 | * @return *this |
486 | * |
487 | * Extracts and stores characters into @a __s until one of the |
488 | * following happens. Note that these criteria are required to be |
489 | * tested in the order listed here, to allow an input line to exactly |
490 | * fill the @a __s array without setting failbit. |
491 | * |
492 | * -# the input sequence reaches end-of-file, in which case eofbit |
493 | * is set in the stream error state |
494 | * -# the next character equals @c __delim, in which case the character |
495 | * is extracted (and therefore counted in @c gcount()) but not stored |
496 | * -# @c __n-1 characters are stored, in which case failbit is set |
497 | * in the stream error state |
498 | * |
499 | * If no characters are extracted, failbit is set. (An empty line of |
500 | * input should therefore not cause failbit to be set.) |
501 | * |
502 | * In any case, a null character is stored in the next location in |
503 | * the array. |
504 | */ |
505 | __istream_type& |
506 | getline(char_type* __s, streamsize __n, char_type __delim); |
507 | |
508 | /** |
509 | * @brief String extraction. |
510 | * @param __s A character array in which to store the data. |
511 | * @param __n Maximum number of characters to extract. |
512 | * @return *this |
513 | * |
514 | * Returns @c getline(__s,__n,widen('\\n')). |
515 | */ |
516 | __istream_type& |
517 | getline(char_type* __s, streamsize __n) |
518 | { return this->getline(__s, __n, this->widen('\n')); } |
519 | |
520 | /** |
521 | * @brief Discarding characters |
522 | * @param __n Number of characters to discard. |
523 | * @param __delim A "stop" character. |
524 | * @return *this |
525 | * |
526 | * Extracts characters and throws them away until one of the |
527 | * following happens: |
528 | * - if @a __n @c != @c std::numeric_limits<int>::max(), @a __n |
529 | * characters are extracted |
530 | * - the input sequence reaches end-of-file |
531 | * - the next character equals @a __delim (in this case, the character |
532 | * is extracted); note that this condition will never occur if |
533 | * @a __delim equals @c traits::eof(). |
534 | * |
535 | * NB: Provide three overloads, instead of the single function |
536 | * (with defaults) mandated by the Standard: this leads to a |
537 | * better performing implementation, while still conforming to |
538 | * the Standard. |
539 | */ |
540 | __istream_type& |
541 | ignore(streamsize __n, int_type __delim); |
542 | |
543 | __istream_type& |
544 | ignore(streamsize __n); |
545 | |
546 | __istream_type& |
547 | ignore(); |
548 | |
549 | /** |
550 | * @brief Looking ahead in the stream |
551 | * @return The next character, or eof(). |
552 | * |
553 | * If, after constructing the sentry object, @c good() is false, |
554 | * returns @c traits::eof(). Otherwise reads but does not extract |
555 | * the next input character. |
556 | */ |
557 | int_type |
558 | peek(); |
559 | |
560 | /** |
561 | * @brief Extraction without delimiters. |
562 | * @param __s A character array. |
563 | * @param __n Maximum number of characters to store. |
564 | * @return *this |
565 | * |
566 | * If the stream state is @c good(), extracts characters and stores |
567 | * them into @a __s until one of the following happens: |
568 | * - @a __n characters are stored |
569 | * - the input sequence reaches end-of-file, in which case the error |
570 | * state is set to @c failbit|eofbit. |
571 | * |
572 | * @note This function is not overloaded on signed char and |
573 | * unsigned char. |
574 | */ |
575 | __istream_type& |
576 | read(char_type* __s, streamsize __n); |
577 | |
578 | /** |
579 | * @brief Extraction until the buffer is exhausted, but no more. |
580 | * @param __s A character array. |
581 | * @param __n Maximum number of characters to store. |
582 | * @return The number of characters extracted. |
583 | * |
584 | * Extracts characters and stores them into @a __s depending on the |
585 | * number of characters remaining in the streambuf's buffer, |
586 | * @c rdbuf()->in_avail(), called @c A here: |
587 | * - if @c A @c == @c -1, sets eofbit and extracts no characters |
588 | * - if @c A @c == @c 0, extracts no characters |
589 | * - if @c A @c > @c 0, extracts @c min(A,n) |
590 | * |
591 | * The goal is to empty the current buffer, and to not request any |
592 | * more from the external input sequence controlled by the streambuf. |
593 | */ |
594 | streamsize |
595 | readsome(char_type* __s, streamsize __n); |
596 | |
597 | /** |
598 | * @brief Unextracting a single character. |
599 | * @param __c The character to push back into the input stream. |
600 | * @return *this |
601 | * |
602 | * If @c rdbuf() is not null, calls @c rdbuf()->sputbackc(c). |
603 | * |
604 | * If @c rdbuf() is null or if @c sputbackc() fails, sets badbit in |
605 | * the error state. |
606 | * |
607 | * @note This function first clears eofbit. Since no characters |
608 | * are extracted, the next call to @c gcount() will return 0, |
609 | * as required by DR 60. |
610 | */ |
611 | __istream_type& |
612 | putback(char_type __c); |
613 | |
614 | /** |
615 | * @brief Unextracting the previous character. |
616 | * @return *this |
617 | * |
618 | * If @c rdbuf() is not null, calls @c rdbuf()->sungetc(c). |
619 | * |
620 | * If @c rdbuf() is null or if @c sungetc() fails, sets badbit in |
621 | * the error state. |
622 | * |
623 | * @note This function first clears eofbit. Since no characters |
624 | * are extracted, the next call to @c gcount() will return 0, |
625 | * as required by DR 60. |
626 | */ |
627 | __istream_type& |
628 | unget(); |
629 | |
630 | /** |
631 | * @brief Synchronizing the stream buffer. |
632 | * @return 0 on success, -1 on failure |
633 | * |
634 | * If @c rdbuf() is a null pointer, returns -1. |
635 | * |
636 | * Otherwise, calls @c rdbuf()->pubsync(), and if that returns -1, |
637 | * sets badbit and returns -1. |
638 | * |
639 | * Otherwise, returns 0. |
640 | * |
641 | * @note This function does not count the number of characters |
642 | * extracted, if any, and therefore does not affect the next |
643 | * call to @c gcount(). |
644 | */ |
645 | int |
646 | sync(); |
647 | |
648 | /** |
649 | * @brief Getting the current read position. |
650 | * @return A file position object. |
651 | * |
652 | * If @c fail() is not false, returns @c pos_type(-1) to indicate |
653 | * failure. Otherwise returns @c rdbuf()->pubseekoff(0,cur,in). |
654 | * |
655 | * @note This function does not count the number of characters |
656 | * extracted, if any, and therefore does not affect the next |
657 | * call to @c gcount(). At variance with putback, unget and |
658 | * seekg, eofbit is not cleared first. |
659 | */ |
660 | pos_type |
661 | tellg(); |
662 | |
663 | /** |
664 | * @brief Changing the current read position. |
665 | * @param __pos A file position object. |
666 | * @return *this |
667 | * |
668 | * If @c fail() is not true, calls @c rdbuf()->pubseekpos(__pos). If |
669 | * that function fails, sets failbit. |
670 | * |
671 | * @note This function first clears eofbit. It does not count the |
672 | * number of characters extracted, if any, and therefore does |
673 | * not affect the next call to @c gcount(). |
674 | */ |
675 | __istream_type& |
676 | seekg(pos_type); |
677 | |
678 | /** |
679 | * @brief Changing the current read position. |
680 | * @param __off A file offset object. |
681 | * @param __dir The direction in which to seek. |
682 | * @return *this |
683 | * |
684 | * If @c fail() is not true, calls @c rdbuf()->pubseekoff(__off,__dir). |
685 | * If that function fails, sets failbit. |
686 | * |
687 | * @note This function first clears eofbit. It does not count the |
688 | * number of characters extracted, if any, and therefore does |
689 | * not affect the next call to @c gcount(). |
690 | */ |
691 | __istream_type& |
692 | seekg(off_type, ios_base::seekdir); |
693 | ///@} |
694 | |
695 | protected: |
696 | basic_istream() |
697 | : _M_gcount(streamsize(0)) |
698 | { this->init(0); } |
699 | |
700 | #if __cplusplus >= 201103L |
701 | basic_istream(const basic_istream&) = delete; |
702 | |
703 | basic_istream(basic_istream&& __rhs) |
704 | : __ios_type(), _M_gcount(__rhs._M_gcount) |
705 | { |
706 | __ios_type::move(__rhs); |
707 | __rhs._M_gcount = 0; |
708 | } |
709 | |
710 | // 27.7.3.3 Assign/swap |
711 | |
712 | basic_istream& operator=(const basic_istream&) = delete; |
713 | |
714 | basic_istream& |
715 | operator=(basic_istream&& __rhs) |
716 | { |
717 | swap(__rhs); |
718 | return *this; |
719 | } |
720 | |
721 | void |
722 | swap(basic_istream& __rhs) |
723 | { |
724 | __ios_type::swap(__rhs); |
725 | std::swap(_M_gcount, __rhs._M_gcount); |
726 | } |
727 | #endif |
728 | |
729 | template<typename _ValueT> |
730 | __istream_type& |
731 | (_ValueT& __v); |
732 | }; |
733 | |
734 | /// Explicit specialization declarations, defined in src/istream.cc. |
735 | template<> |
736 | basic_istream<char>& |
737 | basic_istream<char>:: |
738 | getline(char_type* __s, streamsize __n, char_type __delim); |
739 | |
740 | template<> |
741 | basic_istream<char>& |
742 | basic_istream<char>:: |
743 | ignore(streamsize __n); |
744 | |
745 | template<> |
746 | basic_istream<char>& |
747 | basic_istream<char>:: |
748 | ignore(streamsize __n, int_type __delim); |
749 | |
750 | #ifdef _GLIBCXX_USE_WCHAR_T |
751 | template<> |
752 | basic_istream<wchar_t>& |
753 | basic_istream<wchar_t>:: |
754 | getline(char_type* __s, streamsize __n, char_type __delim); |
755 | |
756 | template<> |
757 | basic_istream<wchar_t>& |
758 | basic_istream<wchar_t>:: |
759 | ignore(streamsize __n); |
760 | |
761 | template<> |
762 | basic_istream<wchar_t>& |
763 | basic_istream<wchar_t>:: |
764 | ignore(streamsize __n, int_type __delim); |
765 | #endif |
766 | |
767 | /** |
768 | * @brief Performs setup work for input streams. |
769 | * |
770 | * Objects of this class are created before all of the standard |
771 | * extractors are run. It is responsible for <em>exception-safe |
772 | * prefix and suffix operations,</em> although only prefix actions |
773 | * are currently required by the standard. |
774 | */ |
775 | template<typename _CharT, typename _Traits> |
776 | class basic_istream<_CharT, _Traits>::sentry |
777 | { |
778 | // Data Members. |
779 | bool _M_ok; |
780 | |
781 | public: |
782 | /// Easy access to dependent types. |
783 | typedef _Traits traits_type; |
784 | typedef basic_streambuf<_CharT, _Traits> __streambuf_type; |
785 | typedef basic_istream<_CharT, _Traits> __istream_type; |
786 | typedef typename __istream_type::__ctype_type __ctype_type; |
787 | typedef typename _Traits::int_type __int_type; |
788 | |
789 | /** |
790 | * @brief The constructor performs all the work. |
791 | * @param __is The input stream to guard. |
792 | * @param __noskipws Whether to consume whitespace or not. |
793 | * |
794 | * If the stream state is good (@a __is.good() is true), then the |
795 | * following actions are performed, otherwise the sentry state |
796 | * is false (<em>not okay</em>) and failbit is set in the |
797 | * stream state. |
798 | * |
799 | * The sentry's preparatory actions are: |
800 | * |
801 | * -# if the stream is tied to an output stream, @c is.tie()->flush() |
802 | * is called to synchronize the output sequence |
803 | * -# if @a __noskipws is false, and @c ios_base::skipws is set in |
804 | * @c is.flags(), the sentry extracts and discards whitespace |
805 | * characters from the stream. The currently imbued locale is |
806 | * used to determine whether each character is whitespace. |
807 | * |
808 | * If the stream state is still good, then the sentry state becomes |
809 | * true (@a okay). |
810 | */ |
811 | explicit |
812 | sentry(basic_istream<_CharT, _Traits>& __is, bool __noskipws = false); |
813 | |
814 | /** |
815 | * @brief Quick status checking. |
816 | * @return The sentry state. |
817 | * |
818 | * For ease of use, sentries may be converted to booleans. The |
819 | * return value is that of the sentry state (true == okay). |
820 | */ |
821 | #if __cplusplus >= 201103L |
822 | explicit |
823 | #endif |
824 | operator bool() const |
825 | { return _M_ok; } |
826 | }; |
827 | |
828 | ///@{ |
829 | /** |
830 | * @brief Character extractors |
831 | * @param __in An input stream. |
832 | * @param __c A character reference. |
833 | * @return in |
834 | * |
835 | * Behaves like one of the formatted arithmetic extractors described in |
836 | * std::basic_istream. After constructing a sentry object with good |
837 | * status, this function extracts a character (if one is available) and |
838 | * stores it in @a __c. Otherwise, sets failbit in the input stream. |
839 | */ |
840 | template<typename _CharT, typename _Traits> |
841 | basic_istream<_CharT, _Traits>& |
842 | operator>>(basic_istream<_CharT, _Traits>& __in, _CharT& __c); |
843 | |
844 | template<class _Traits> |
845 | inline basic_istream<char, _Traits>& |
846 | operator>>(basic_istream<char, _Traits>& __in, unsigned char& __c) |
847 | { return (__in >> reinterpret_cast<char&>(__c)); } |
848 | |
849 | template<class _Traits> |
850 | inline basic_istream<char, _Traits>& |
851 | operator>>(basic_istream<char, _Traits>& __in, signed char& __c) |
852 | { return (__in >> reinterpret_cast<char&>(__c)); } |
853 | ///@} |
854 | |
855 | |
856 | template<typename _CharT, typename _Traits> |
857 | void |
858 | (basic_istream<_CharT, _Traits>&, _CharT*, streamsize); |
859 | |
860 | void (istream&, char*, streamsize); |
861 | |
862 | ///@{ |
863 | /** |
864 | * @brief Character string extractors |
865 | * @param __in An input stream. |
866 | * @param __s A character array (or a pointer to an array before C++20). |
867 | * @return __in |
868 | * |
869 | * Behaves like one of the formatted arithmetic extractors described in |
870 | * `std::basic_istream`. After constructing a sentry object with good |
871 | * status, this function extracts up to `n` characters and stores them |
872 | * into the array `__s`. `n` is defined as: |
873 | * |
874 | * - if `width()` is greater than zero, `n` is `min(width(), n)` |
875 | * - otherwise `n` is the number of elements of the array |
876 | * - (before C++20 the pointer is assumed to point to an array of |
877 | * the largest possible size for an array of `char_type`). |
878 | * |
879 | * Characters are extracted and stored until one of the following happens: |
880 | * - `n - 1` characters are stored |
881 | * - EOF is reached |
882 | * - the next character is whitespace according to the current locale |
883 | * |
884 | * `width(0)` is then called for the input stream. |
885 | * |
886 | * If no characters are extracted, sets failbit. |
887 | */ |
888 | |
889 | #if __cplusplus <= 201703L |
890 | template<typename _CharT, typename _Traits> |
891 | __attribute__((__nonnull__(2), __access__(__write_only__, 2))) |
892 | inline basic_istream<_CharT, _Traits>& |
893 | operator>>(basic_istream<_CharT, _Traits>& __in, _CharT* __s) |
894 | { |
895 | #ifdef __OPTIMIZE__ |
896 | // Function inlining might make the buffer size known, allowing us to |
897 | // prevent overflow. |
898 | size_t __n = __builtin_object_size(__s, 0); |
899 | if (__n < sizeof(_CharT)) |
900 | { |
901 | // There is not even space for the required null terminator. |
902 | __glibcxx_assert(__n >= sizeof(_CharT)); |
903 | // No point calling __istream_extract, but still need to reset width. |
904 | __in.width(0); |
905 | __in.setstate(ios_base::failbit); |
906 | } |
907 | else if (__n != (size_t)-1) |
908 | { |
909 | __n /= sizeof(_CharT); |
910 | streamsize __w = __in.width(); |
911 | std::__istream_extract(__in, __s, __n); |
912 | if (__in.good() && (__w <= 0 || __n < __w)) |
913 | { |
914 | // Stopped extracting early to avoid overflowing the buffer, |
915 | // but might have stopped anyway (and set eofbit) if at EOF. |
916 | const typename _Traits::int_type __c = __in.rdbuf()->sgetc(); |
917 | const bool __eof = _Traits::eq_int_type(__c, _Traits::eof()); |
918 | if (__builtin_expect(__eof, true)) // Assume EOF, not overflow. |
919 | __in.setstate(ios_base::eofbit); |
920 | } |
921 | } |
922 | else |
923 | #endif // __OPTIMIZE |
924 | { |
925 | // Buffer size is unknown, have to assume it's huge. |
926 | streamsize __n = __gnu_cxx::__numeric_traits<streamsize>::__max; |
927 | __n /= sizeof(_CharT); |
928 | std::__istream_extract(__in, __s, __n); |
929 | } |
930 | return __in; |
931 | } |
932 | |
933 | template<class _Traits> |
934 | __attribute__((__nonnull__(2), __access__(__write_only__, 2))) |
935 | inline basic_istream<char, _Traits>& |
936 | operator>>(basic_istream<char, _Traits>& __in, unsigned char* __s) |
937 | { return __in >> reinterpret_cast<char*>(__s); } |
938 | |
939 | template<class _Traits> |
940 | __attribute__((__nonnull__(2), __access__(__write_only__, 2))) |
941 | inline basic_istream<char, _Traits>& |
942 | operator>>(basic_istream<char, _Traits>& __in, signed char* __s) |
943 | { return __in >> reinterpret_cast<char*>(__s); } |
944 | #else |
945 | // _GLIBCXX_RESOLVE_LIB_DEFECTS |
946 | // 2499. operator>>(istream&, char*) makes it hard to avoid buffer overflows |
947 | template<typename _CharT, typename _Traits, size_t _Num> |
948 | inline basic_istream<_CharT, _Traits>& |
949 | operator>>(basic_istream<_CharT, _Traits>& __in, _CharT (&__s)[_Num]) |
950 | { |
951 | static_assert(_Num <= __gnu_cxx::__numeric_traits<streamsize>::__max); |
952 | std::__istream_extract(__in, __s, _Num); |
953 | return __in; |
954 | } |
955 | |
956 | template<class _Traits, size_t _Num> |
957 | inline basic_istream<char, _Traits>& |
958 | operator>>(basic_istream<char, _Traits>& __in, unsigned char (&__s)[_Num]) |
959 | { return __in >> reinterpret_cast<char(&)[_Num]>(__s); } |
960 | |
961 | template<class _Traits, size_t _Num> |
962 | inline basic_istream<char, _Traits>& |
963 | operator>>(basic_istream<char, _Traits>& __in, signed char (&__s)[_Num]) |
964 | { return __in >> reinterpret_cast<char(&)[_Num]>(__s); } |
965 | #endif |
966 | ///@} |
967 | |
968 | /** |
969 | * @brief Template class basic_iostream |
970 | * @ingroup io |
971 | * |
972 | * @tparam _CharT Type of character stream. |
973 | * @tparam _Traits Traits for character type, defaults to |
974 | * char_traits<_CharT>. |
975 | * |
976 | * This class multiply inherits from the input and output stream classes |
977 | * simply to provide a single interface. |
978 | */ |
979 | template<typename _CharT, typename _Traits> |
980 | class basic_iostream |
981 | : public basic_istream<_CharT, _Traits>, |
982 | public basic_ostream<_CharT, _Traits> |
983 | { |
984 | public: |
985 | // _GLIBCXX_RESOLVE_LIB_DEFECTS |
986 | // 271. basic_iostream missing typedefs |
987 | // Types (inherited): |
988 | typedef _CharT char_type; |
989 | typedef typename _Traits::int_type int_type; |
990 | typedef typename _Traits::pos_type pos_type; |
991 | typedef typename _Traits::off_type off_type; |
992 | typedef _Traits traits_type; |
993 | |
994 | // Non-standard Types: |
995 | typedef basic_istream<_CharT, _Traits> __istream_type; |
996 | typedef basic_ostream<_CharT, _Traits> __ostream_type; |
997 | |
998 | /** |
999 | * @brief Constructor does nothing. |
1000 | * |
1001 | * Both of the parent classes are initialized with the same |
1002 | * streambuf pointer passed to this constructor. |
1003 | */ |
1004 | explicit |
1005 | basic_iostream(basic_streambuf<_CharT, _Traits>* __sb) |
1006 | : __istream_type(__sb), __ostream_type(__sb) { } |
1007 | |
1008 | /** |
1009 | * @brief Destructor does nothing. |
1010 | */ |
1011 | virtual |
1012 | ~basic_iostream() { } |
1013 | |
1014 | protected: |
1015 | basic_iostream() |
1016 | : __istream_type(), __ostream_type() { } |
1017 | |
1018 | #if __cplusplus >= 201103L |
1019 | basic_iostream(const basic_iostream&) = delete; |
1020 | |
1021 | basic_iostream(basic_iostream&& __rhs) |
1022 | : __istream_type(std::move(__rhs)), __ostream_type(*this) |
1023 | { } |
1024 | |
1025 | // 27.7.3.3 Assign/swap |
1026 | |
1027 | basic_iostream& operator=(const basic_iostream&) = delete; |
1028 | |
1029 | basic_iostream& |
1030 | operator=(basic_iostream&& __rhs) |
1031 | { |
1032 | swap(__rhs); |
1033 | return *this; |
1034 | } |
1035 | |
1036 | void |
1037 | swap(basic_iostream& __rhs) |
1038 | { __istream_type::swap(__rhs); } |
1039 | #endif |
1040 | }; |
1041 | |
1042 | /** |
1043 | * @brief Quick and easy way to eat whitespace |
1044 | * |
1045 | * This manipulator extracts whitespace characters, stopping when the |
1046 | * next character is non-whitespace, or when the input sequence is empty. |
1047 | * If the sequence is empty, @c eofbit is set in the stream, but not |
1048 | * @c failbit. |
1049 | * |
1050 | * The current locale is used to distinguish whitespace characters. |
1051 | * |
1052 | * Example: |
1053 | * @code |
1054 | * MyClass mc; |
1055 | * |
1056 | * std::cin >> std::ws >> mc; |
1057 | * @endcode |
1058 | * will skip leading whitespace before calling operator>> on cin and your |
1059 | * object. Note that the same effect can be achieved by creating a |
1060 | * std::basic_istream::sentry inside your definition of operator>>. |
1061 | */ |
1062 | template<typename _CharT, typename _Traits> |
1063 | basic_istream<_CharT, _Traits>& |
1064 | ws(basic_istream<_CharT, _Traits>& __is); |
1065 | |
1066 | #if __cplusplus >= 201103L |
1067 | // C++11 27.7.2.6 Rvalue stream extraction [istream.rvalue] |
1068 | // _GLIBCXX_RESOLVE_LIB_DEFECTS |
1069 | // 2328. Rvalue stream extraction should use perfect forwarding |
1070 | // 1203. More useful rvalue stream insertion |
1071 | |
1072 | #if __cpp_concepts >= 201907L && __glibcxx_type_trait_variable_templates |
1073 | template<typename _Is, typename _Tp> |
1074 | requires __derived_from_ios_base<_Is> |
1075 | && requires (_Is& __is, _Tp&& __t) { __is >> std::forward<_Tp>(__t); } |
1076 | using = _Is&&; |
1077 | #else |
1078 | template<typename _Is, typename _Tp, |
1079 | typename = _Require_derived_from_ios_base<_Is>, |
1080 | typename = decltype(std::declval<_Is&>() >> std::declval<_Tp>())> |
1081 | using __rvalue_stream_extraction_t = _Is&&; |
1082 | #endif |
1083 | |
1084 | /** |
1085 | * @brief Generic extractor for rvalue stream |
1086 | * @param __is An input stream. |
1087 | * @param __x A reference to the extraction target. |
1088 | * @return __is |
1089 | * |
1090 | * This is just a forwarding function to allow extraction from |
1091 | * rvalue streams since they won't bind to the extractor functions |
1092 | * that take an lvalue reference. |
1093 | */ |
1094 | template<typename _Istream, typename _Tp> |
1095 | inline __rvalue_stream_extraction_t<_Istream, _Tp> |
1096 | operator>>(_Istream&& __is, _Tp&& __x) |
1097 | { |
1098 | __is >> std::forward<_Tp>(__x); |
1099 | return std::move(__is); |
1100 | } |
1101 | #endif // C++11 |
1102 | |
1103 | _GLIBCXX_END_NAMESPACE_VERSION |
1104 | } // namespace |
1105 | |
1106 | #include <bits/istream.tcc> |
1107 | |
1108 | #endif /* _GLIBCXX_ISTREAM */ |
1109 | |