1 : // Input streams -*- C++ -*-
2 :
3 : // Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
4 : // 2006, 2007, 2008, 2009, 2010, 2011
5 : // Free Software Foundation, Inc.
6 : //
7 : // This file is part of the GNU ISO C++ Library. This library is free
8 : // software; you can redistribute it and/or modify it under the
9 : // terms of the GNU General Public License as published by the
10 : // Free Software Foundation; either version 3, or (at your option)
11 : // any later version.
12 :
13 : // This library is distributed in the hope that it will be useful,
14 : // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 : // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 : // GNU General Public License for more details.
17 :
18 : // Under Section 7 of GPL version 3, you are granted additional
19 : // permissions described in the GCC Runtime Library Exception, version
20 : // 3.1, as published by the Free Software Foundation.
21 :
22 : // You should have received a copy of the GNU General Public License and
23 : // a copy of the GCC Runtime Library Exception along with this program;
24 : // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
25 : // <http://www.gnu.org/licenses/>.
26 :
27 : //
28 : // ISO C++ 14882: 27.6.1 Input streams
29 : //
30 :
31 : /** @file include/istream
32 : * This is a Standard C++ Library header.
33 : */
34 :
35 : #ifndef _GLIBCXX_ISTREAM
36 : #define _GLIBCXX_ISTREAM 1
37 :
38 : #pragma GCC system_header
39 :
40 : #include <ios>
41 : #include <ostream>
42 :
43 : namespace std _GLIBCXX_VISIBILITY(default)
44 : {
45 : _GLIBCXX_BEGIN_NAMESPACE_VERSION
46 :
47 : // [27.6.1.1] Template class basic_istream
48 : /**
49 : * @brief Controlling input.
50 : * @ingroup io
51 : *
52 : * This is the base class for all input streams. It provides text
53 : * formatting of all builtin types, and communicates with any class
54 : * derived from basic_streambuf to do the actual input.
55 : */
56 : template<typename _CharT, typename _Traits>
57 : class basic_istream : virtual public basic_ios<_CharT, _Traits>
58 : {
59 : public:
60 : // Types (inherited from basic_ios (27.4.4)):
61 : typedef _CharT char_type;
62 : typedef typename _Traits::int_type int_type;
63 : typedef typename _Traits::pos_type pos_type;
64 : typedef typename _Traits::off_type off_type;
65 : typedef _Traits traits_type;
66 :
67 : // Non-standard Types:
68 : typedef basic_streambuf<_CharT, _Traits> __streambuf_type;
69 : typedef basic_ios<_CharT, _Traits> __ios_type;
70 : typedef basic_istream<_CharT, _Traits> __istream_type;
71 : typedef num_get<_CharT, istreambuf_iterator<_CharT, _Traits> >
72 : __num_get_type;
73 : typedef ctype<_CharT> __ctype_type;
74 :
75 : protected:
76 : // Data Members:
77 : /**
78 : * The number of characters extracted in the previous unformatted
79 : * function; see gcount().
80 : */
81 : streamsize _M_gcount;
82 :
83 : public:
84 : // [27.6.1.1.1] constructor/destructor
85 : /**
86 : * @brief Base constructor.
87 : *
88 : * This ctor is almost never called by the user directly, rather from
89 : * derived classes' initialization lists, which pass a pointer to
90 : * their own stream buffer.
91 : */
92 : explicit
93 : basic_istream(__streambuf_type* __sb)
94 : : _M_gcount(streamsize(0))
95 : { this->init(__sb); }
96 :
97 : /**
98 : * @brief Base destructor.
99 : *
100 : * This does very little apart from providing a virtual base dtor.
101 : */
102 : virtual
103 0 : ~basic_istream()
104 0 : { _M_gcount = streamsize(0); }
105 :
106 : // [27.6.1.1.2] prefix/suffix
107 : class sentry;
108 : friend class sentry;
109 :
110 : // [27.6.1.2] formatted input
111 : // [27.6.1.2.3] basic_istream::operator>>
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 : // [27.6.1.2.2] arithmetic extractors
141 : /**
142 : * @name Arithmetic 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. The original exception will then
157 : * be rethrown.
158 : */
159 : //@{
160 : /**
161 : * @brief Basic arithmetic extractors
162 : * @param A variable of builtin type.
163 : * @return @c *this if successful
164 : *
165 : * These functions use the stream's current locale (specifically, the
166 : * @c num_get facet) to parse the input data.
167 : */
168 : __istream_type&
169 : operator>>(bool& __n)
170 : { return _M_extract(__n); }
171 :
172 : __istream_type&
173 : operator>>(short& __n);
174 :
175 : __istream_type&
176 : operator>>(unsigned short& __n)
177 : { return _M_extract(__n); }
178 :
179 : __istream_type&
180 : operator>>(int& __n);
181 :
182 : __istream_type&
183 : operator>>(unsigned int& __n)
184 : { return _M_extract(__n); }
185 :
186 : __istream_type&
187 : operator>>(long& __n)
188 : { return _M_extract(__n); }
189 :
190 : __istream_type&
191 : operator>>(unsigned long& __n)
192 : { return _M_extract(__n); }
193 :
194 : #ifdef _GLIBCXX_USE_LONG_LONG
195 : __istream_type&
196 : operator>>(long long& __n)
197 : { return _M_extract(__n); }
198 :
199 : __istream_type&
200 : operator>>(unsigned long long& __n)
201 : { return _M_extract(__n); }
202 : #endif
203 :
204 : __istream_type&
205 : operator>>(float& __f)
206 : { return _M_extract(__f); }
207 :
208 : __istream_type&
209 : operator>>(double& __f)
210 : { return _M_extract(__f); }
211 :
212 : __istream_type&
213 : operator>>(long double& __f)
214 : { return _M_extract(__f); }
215 :
216 : __istream_type&
217 : operator>>(void*& __p)
218 : { return _M_extract(__p); }
219 :
220 : /**
221 : * @brief Extracting into another streambuf.
222 : * @param sb A pointer to a streambuf
223 : *
224 : * This function behaves like one of the basic arithmetic extractors,
225 : * in that it also constructs a sentry object and has the same error
226 : * handling behavior.
227 : *
228 : * If @a sb is NULL, the stream will set failbit in its error state.
229 : *
230 : * Characters are extracted from this stream and inserted into the
231 : * @a sb streambuf until one of the following occurs:
232 : *
233 : * - the input stream reaches end-of-file,
234 : * - insertion into the output buffer fails (in this case, the
235 : * character that would have been inserted is not extracted), or
236 : * - an exception occurs (and in this case is caught)
237 : *
238 : * If the function inserts no characters, failbit is set.
239 : */
240 : __istream_type&
241 : operator>>(__streambuf_type* __sb);
242 : //@}
243 :
244 : // [27.6.1.3] unformatted input
245 : /**
246 : * @brief Character counting
247 : * @return The number of characters extracted by the previous
248 : * unformatted input function dispatched for this stream.
249 : */
250 : streamsize
251 : gcount() const
252 : { return _M_gcount; }
253 :
254 : /**
255 : * @name Unformatted Input Functions
256 : *
257 : * All the unformatted input functions have some common behavior.
258 : * Each starts by constructing a temporary object of type
259 : * std::basic_istream::sentry with the second argument (noskipws)
260 : * set to true. This has several effects, concluding with the
261 : * setting of a status flag; see the sentry documentation for more.
262 : *
263 : * If the sentry status is good, the function tries to extract
264 : * whatever data is appropriate for the type of the argument.
265 : *
266 : * The number of characters extracted is stored for later retrieval
267 : * by gcount().
268 : *
269 : * If an exception is thrown during extraction, ios_base::badbit
270 : * will be turned on in the stream's error state without causing an
271 : * ios_base::failure to be thrown. The original exception will then
272 : * be rethrown.
273 : */
274 : //@{
275 : /**
276 : * @brief Simple extraction.
277 : * @return A character, or eof().
278 : *
279 : * Tries to extract a character. If none are available, sets failbit
280 : * and returns traits::eof().
281 : */
282 : int_type
283 : get();
284 :
285 : /**
286 : * @brief Simple extraction.
287 : * @param c The character in which to store data.
288 : * @return *this
289 : *
290 : * Tries to extract a character and store it in @a c. If none are
291 : * available, sets failbit and returns traits::eof().
292 : *
293 : * @note This function is not overloaded on signed char and
294 : * unsigned char.
295 : */
296 : __istream_type&
297 : get(char_type& __c);
298 :
299 : /**
300 : * @brief Simple multiple-character extraction.
301 : * @param s Pointer to an array.
302 : * @param n Maximum number of characters to store in @a s.
303 : * @param delim A "stop" character.
304 : * @return *this
305 : *
306 : * Characters are extracted and stored into @a s until one of the
307 : * following happens:
308 : *
309 : * - @c n-1 characters are stored
310 : * - the input sequence reaches EOF
311 : * - the next character equals @a delim, in which case the character
312 : * is not extracted
313 : *
314 : * If no characters are stored, failbit is set in the stream's error
315 : * state.
316 : *
317 : * In any case, a null character is stored into the next location in
318 : * the array.
319 : *
320 : * @note This function is not overloaded on signed char and
321 : * unsigned char.
322 : */
323 : __istream_type&
324 : get(char_type* __s, streamsize __n, char_type __delim);
325 :
326 : /**
327 : * @brief Simple multiple-character extraction.
328 : * @param s Pointer to an array.
329 : * @param n Maximum number of characters to store in @a s.
330 : * @return *this
331 : *
332 : * Returns @c get(s,n,widen('\\n')).
333 : */
334 : __istream_type&
335 : get(char_type* __s, streamsize __n)
336 : { return this->get(__s, __n, this->widen('\n')); }
337 :
338 : /**
339 : * @brief Extraction into another streambuf.
340 : * @param sb A streambuf in which to store data.
341 : * @param delim A "stop" character.
342 : * @return *this
343 : *
344 : * Characters are extracted and inserted into @a sb until one of the
345 : * following happens:
346 : *
347 : * - the input sequence reaches EOF
348 : * - insertion into the output buffer fails (in this case, the
349 : * character that would have been inserted is not extracted)
350 : * - the next character equals @a delim (in this case, the character
351 : * is not extracted)
352 : * - an exception occurs (and in this case is caught)
353 : *
354 : * If no characters are stored, failbit is set in the stream's error
355 : * state.
356 : */
357 : __istream_type&
358 : get(__streambuf_type& __sb, char_type __delim);
359 :
360 : /**
361 : * @brief Extraction into another streambuf.
362 : * @param sb A streambuf in which to store data.
363 : * @return *this
364 : *
365 : * Returns @c get(sb,widen('\\n')).
366 : */
367 : __istream_type&
368 : get(__streambuf_type& __sb)
369 : { return this->get(__sb, this->widen('\n')); }
370 :
371 : /**
372 : * @brief String extraction.
373 : * @param s A character array in which to store the data.
374 : * @param n Maximum number of characters to extract.
375 : * @param delim A "stop" character.
376 : * @return *this
377 : *
378 : * Extracts and stores characters into @a s until one of the
379 : * following happens. Note that these criteria are required to be
380 : * tested in the order listed here, to allow an input line to exactly
381 : * fill the @a s array without setting failbit.
382 : *
383 : * -# the input sequence reaches end-of-file, in which case eofbit
384 : * is set in the stream error state
385 : * -# the next character equals @c delim, in which case the character
386 : * is extracted (and therefore counted in @c gcount()) but not stored
387 : * -# @c n-1 characters are stored, in which case failbit is set
388 : * in the stream error state
389 : *
390 : * If no characters are extracted, failbit is set. (An empty line of
391 : * input should therefore not cause failbit to be set.)
392 : *
393 : * In any case, a null character is stored in the next location in
394 : * the array.
395 : */
396 : __istream_type&
397 : getline(char_type* __s, streamsize __n, char_type __delim);
398 :
399 : /**
400 : * @brief String extraction.
401 : * @param s A character array in which to store the data.
402 : * @param n Maximum number of characters to extract.
403 : * @return *this
404 : *
405 : * Returns @c getline(s,n,widen('\\n')).
406 : */
407 : __istream_type&
408 : getline(char_type* __s, streamsize __n)
409 : { return this->getline(__s, __n, this->widen('\n')); }
410 :
411 : /**
412 : * @brief Discarding characters
413 : * @param n Number of characters to discard.
414 : * @param delim A "stop" character.
415 : * @return *this
416 : *
417 : * Extracts characters and throws them away until one of the
418 : * following happens:
419 : * - if @a n @c != @c std::numeric_limits<int>::max(), @a n
420 : * characters are extracted
421 : * - the input sequence reaches end-of-file
422 : * - the next character equals @a delim (in this case, the character
423 : * is extracted); note that this condition will never occur if
424 : * @a delim equals @c traits::eof().
425 : *
426 : * NB: Provide three overloads, instead of the single function
427 : * (with defaults) mandated by the Standard: this leads to a
428 : * better performing implementation, while still conforming to
429 : * the Standard.
430 : */
431 : __istream_type&
432 : ignore();
433 :
434 : __istream_type&
435 : ignore(streamsize __n);
436 :
437 : __istream_type&
438 : ignore(streamsize __n, int_type __delim);
439 :
440 : /**
441 : * @brief Looking ahead in the stream
442 : * @return The next character, or eof().
443 : *
444 : * If, after constructing the sentry object, @c good() is false,
445 : * returns @c traits::eof(). Otherwise reads but does not extract
446 : * the next input character.
447 : */
448 : int_type
449 : peek();
450 :
451 : /**
452 : * @brief Extraction without delimiters.
453 : * @param s A character array.
454 : * @param n Maximum number of characters to store.
455 : * @return *this
456 : *
457 : * If the stream state is @c good(), extracts characters and stores
458 : * them into @a s until one of the following happens:
459 : * - @a n characters are stored
460 : * - the input sequence reaches end-of-file, in which case the error
461 : * state is set to @c failbit|eofbit.
462 : *
463 : * @note This function is not overloaded on signed char and
464 : * unsigned char.
465 : */
466 : __istream_type&
467 : read(char_type* __s, streamsize __n);
468 :
469 : /**
470 : * @brief Extraction until the buffer is exhausted, but no more.
471 : * @param s A character array.
472 : * @param n Maximum number of characters to store.
473 : * @return The number of characters extracted.
474 : *
475 : * Extracts characters and stores them into @a s depending on the
476 : * number of characters remaining in the streambuf's buffer,
477 : * @c rdbuf()->in_avail(), called @c A here:
478 : * - if @c A @c == @c -1, sets eofbit and extracts no characters
479 : * - if @c A @c == @c 0, extracts no characters
480 : * - if @c A @c > @c 0, extracts @c min(A,n)
481 : *
482 : * The goal is to empty the current buffer, and to not request any
483 : * more from the external input sequence controlled by the streambuf.
484 : */
485 : streamsize
486 : readsome(char_type* __s, streamsize __n);
487 :
488 : /**
489 : * @brief Unextracting a single character.
490 : * @param c The character to push back into the input stream.
491 : * @return *this
492 : *
493 : * If @c rdbuf() is not null, calls @c rdbuf()->sputbackc(c).
494 : *
495 : * If @c rdbuf() is null or if @c sputbackc() fails, sets badbit in
496 : * the error state.
497 : *
498 : * @note This function first clears eofbit. Since no characters
499 : * are extracted, the next call to @c gcount() will return 0,
500 : * as required by DR 60.
501 : */
502 : __istream_type&
503 : putback(char_type __c);
504 :
505 : /**
506 : * @brief Unextracting the previous character.
507 : * @return *this
508 : *
509 : * If @c rdbuf() is not null, calls @c rdbuf()->sungetc(c).
510 : *
511 : * If @c rdbuf() is null or if @c sungetc() fails, sets badbit in
512 : * the error state.
513 : *
514 : * @note This function first clears eofbit. Since no characters
515 : * are extracted, the next call to @c gcount() will return 0,
516 : * as required by DR 60.
517 : */
518 : __istream_type&
519 : unget();
520 :
521 : /**
522 : * @brief Synchronizing the stream buffer.
523 : * @return 0 on success, -1 on failure
524 : *
525 : * If @c rdbuf() is a null pointer, returns -1.
526 : *
527 : * Otherwise, calls @c rdbuf()->pubsync(), and if that returns -1,
528 : * sets badbit and returns -1.
529 : *
530 : * Otherwise, returns 0.
531 : *
532 : * @note This function does not count the number of characters
533 : * extracted, if any, and therefore does not affect the next
534 : * call to @c gcount().
535 : */
536 : int
537 : sync();
538 :
539 : /**
540 : * @brief Getting the current read position.
541 : * @return A file position object.
542 : *
543 : * If @c fail() is not false, returns @c pos_type(-1) to indicate
544 : * failure. Otherwise returns @c rdbuf()->pubseekoff(0,cur,in).
545 : *
546 : * @note This function does not count the number of characters
547 : * extracted, if any, and therefore does not affect the next
548 : * call to @c gcount(). At variance with putback, unget and
549 : * seekg, eofbit is not cleared first.
550 : */
551 : pos_type
552 : tellg();
553 :
554 : /**
555 : * @brief Changing the current read position.
556 : * @param pos A file position object.
557 : * @return *this
558 : *
559 : * If @c fail() is not true, calls @c rdbuf()->pubseekpos(pos). If
560 : * that function fails, sets failbit.
561 : *
562 : * @note This function first clears eofbit. It does not count the
563 : * number of characters extracted, if any, and therefore does
564 : * not affect the next call to @c gcount().
565 : */
566 : __istream_type&
567 : seekg(pos_type);
568 :
569 : /**
570 : * @brief Changing the current read position.
571 : * @param off A file offset object.
572 : * @param dir The direction in which to seek.
573 : * @return *this
574 : *
575 : * If @c fail() is not true, calls @c rdbuf()->pubseekoff(off,dir).
576 : * If that function fails, sets failbit.
577 : *
578 : * @note This function first clears eofbit. It does not count the
579 : * number of characters extracted, if any, and therefore does
580 : * not affect the next call to @c gcount().
581 : */
582 : __istream_type&
583 : seekg(off_type, ios_base::seekdir);
584 : //@}
585 :
586 : protected:
587 0 : basic_istream()
588 0 : : _M_gcount(streamsize(0))
589 0 : { this->init(0); }
590 :
591 : template<typename _ValueT>
592 : __istream_type&
593 : _M_extract(_ValueT& __v);
594 : };
595 :
596 : // Explicit specialization declarations, defined in src/istream.cc.
597 : template<>
598 : basic_istream<char>&
599 : basic_istream<char>::
600 : getline(char_type* __s, streamsize __n, char_type __delim);
601 :
602 : template<>
603 : basic_istream<char>&
604 : basic_istream<char>::
605 : ignore(streamsize __n);
606 :
607 : template<>
608 : basic_istream<char>&
609 : basic_istream<char>::
610 : ignore(streamsize __n, int_type __delim);
611 :
612 : #ifdef _GLIBCXX_USE_WCHAR_T
613 : template<>
614 : basic_istream<wchar_t>&
615 : basic_istream<wchar_t>::
616 : getline(char_type* __s, streamsize __n, char_type __delim);
617 :
618 : template<>
619 : basic_istream<wchar_t>&
620 : basic_istream<wchar_t>::
621 : ignore(streamsize __n);
622 :
623 : template<>
624 : basic_istream<wchar_t>&
625 : basic_istream<wchar_t>::
626 : ignore(streamsize __n, int_type __delim);
627 : #endif
628 :
629 : /**
630 : * @brief Performs setup work for input streams.
631 : *
632 : * Objects of this class are created before all of the standard
633 : * extractors are run. It is responsible for <em>exception-safe
634 : * prefix and suffix operations,</em> although only prefix actions
635 : * are currently required by the standard.
636 : */
637 : template<typename _CharT, typename _Traits>
638 : class basic_istream<_CharT, _Traits>::sentry
639 : {
640 : // Data Members.
641 : bool _M_ok;
642 :
643 : public:
644 : /// Easy access to dependant types.
645 : typedef _Traits traits_type;
646 : typedef basic_streambuf<_CharT, _Traits> __streambuf_type;
647 : typedef basic_istream<_CharT, _Traits> __istream_type;
648 : typedef typename __istream_type::__ctype_type __ctype_type;
649 : typedef typename _Traits::int_type __int_type;
650 :
651 : /**
652 : * @brief The constructor performs all the work.
653 : * @param is The input stream to guard.
654 : * @param noskipws Whether to consume whitespace or not.
655 : *
656 : * If the stream state is good (@a is.good() is true), then the
657 : * following actions are performed, otherwise the sentry state
658 : * is false (<em>not okay</em>) and failbit is set in the
659 : * stream state.
660 : *
661 : * The sentry's preparatory actions are:
662 : *
663 : * -# if the stream is tied to an output stream, @c is.tie()->flush()
664 : * is called to synchronize the output sequence
665 : * -# if @a noskipws is false, and @c ios_base::skipws is set in
666 : * @c is.flags(), the sentry extracts and discards whitespace
667 : * characters from the stream. The currently imbued locale is
668 : * used to determine whether each character is whitespace.
669 : *
670 : * If the stream state is still good, then the sentry state becomes
671 : * true (@a okay).
672 : */
673 : explicit
674 : sentry(basic_istream<_CharT, _Traits>& __is, bool __noskipws = false);
675 :
676 : /**
677 : * @brief Quick status checking.
678 : * @return The sentry state.
679 : *
680 : * For ease of use, sentries may be converted to booleans. The
681 : * return value is that of the sentry state (true == okay).
682 : */
683 : #ifdef __GXX_EXPERIMENTAL_CXX0X__
684 : explicit
685 : #endif
686 : operator bool() const
687 : { return _M_ok; }
688 : };
689 :
690 : // [27.6.1.2.3] character extraction templates
691 : //@{
692 : /**
693 : * @brief Character extractors
694 : * @param in An input stream.
695 : * @param c A character reference.
696 : * @return in
697 : *
698 : * Behaves like one of the formatted arithmetic extractors described in
699 : * std::basic_istream. After constructing a sentry object with good
700 : * status, this function extracts a character (if one is available) and
701 : * stores it in @a c. Otherwise, sets failbit in the input stream.
702 : */
703 : template<typename _CharT, typename _Traits>
704 : basic_istream<_CharT, _Traits>&
705 : operator>>(basic_istream<_CharT, _Traits>& __in, _CharT& __c);
706 :
707 : template<class _Traits>
708 : inline basic_istream<char, _Traits>&
709 : operator>>(basic_istream<char, _Traits>& __in, unsigned char& __c)
710 : { return (__in >> reinterpret_cast<char&>(__c)); }
711 :
712 : template<class _Traits>
713 : inline basic_istream<char, _Traits>&
714 : operator>>(basic_istream<char, _Traits>& __in, signed char& __c)
715 : { return (__in >> reinterpret_cast<char&>(__c)); }
716 : //@}
717 :
718 : //@{
719 : /**
720 : * @brief Character string extractors
721 : * @param in An input stream.
722 : * @param s A pointer to a character array.
723 : * @return in
724 : *
725 : * Behaves like one of the formatted arithmetic extractors described in
726 : * std::basic_istream. After constructing a sentry object with good
727 : * status, this function extracts up to @c n characters and stores them
728 : * into the array starting at @a s. @c n is defined as:
729 : *
730 : * - if @c width() is greater than zero, @c n is width() otherwise
731 : * - @c n is <em>the number of elements of the largest array of *
732 : * - @c char_type that can store a terminating @c eos.</em>
733 : * - [27.6.1.2.3]/6
734 : *
735 : * Characters are extracted and stored until one of the following happens:
736 : * - @c n-1 characters are stored
737 : * - EOF is reached
738 : * - the next character is whitespace according to the current locale
739 : * - the next character is a null byte (i.e., @c charT() )
740 : *
741 : * @c width(0) is then called for the input stream.
742 : *
743 : * If no characters are extracted, sets failbit.
744 : */
745 : template<typename _CharT, typename _Traits>
746 : basic_istream<_CharT, _Traits>&
747 : operator>>(basic_istream<_CharT, _Traits>& __in, _CharT* __s);
748 :
749 : // Explicit specialization declaration, defined in src/istream.cc.
750 : template<>
751 : basic_istream<char>&
752 : operator>>(basic_istream<char>& __in, char* __s);
753 :
754 : template<class _Traits>
755 : inline basic_istream<char, _Traits>&
756 : operator>>(basic_istream<char, _Traits>& __in, unsigned char* __s)
757 : { return (__in >> reinterpret_cast<char*>(__s)); }
758 :
759 : template<class _Traits>
760 : inline basic_istream<char, _Traits>&
761 : operator>>(basic_istream<char, _Traits>& __in, signed char* __s)
762 : { return (__in >> reinterpret_cast<char*>(__s)); }
763 : //@}
764 :
765 : // 27.6.1.5 Template class basic_iostream
766 : /**
767 : * @brief Merging istream and ostream capabilities.
768 : * @ingroup io
769 : *
770 : * This class multiply inherits from the input and output stream classes
771 : * simply to provide a single interface.
772 : */
773 : template<typename _CharT, typename _Traits>
774 : class basic_iostream
775 : : public basic_istream<_CharT, _Traits>,
776 : public basic_ostream<_CharT, _Traits>
777 : {
778 : public:
779 : // _GLIBCXX_RESOLVE_LIB_DEFECTS
780 : // 271. basic_iostream missing typedefs
781 : // Types (inherited):
782 : typedef _CharT char_type;
783 : typedef typename _Traits::int_type int_type;
784 : typedef typename _Traits::pos_type pos_type;
785 : typedef typename _Traits::off_type off_type;
786 : typedef _Traits traits_type;
787 :
788 : // Non-standard Types:
789 : typedef basic_istream<_CharT, _Traits> __istream_type;
790 : typedef basic_ostream<_CharT, _Traits> __ostream_type;
791 :
792 : /**
793 : * @brief Constructor does nothing.
794 : *
795 : * Both of the parent classes are initialized with the same
796 : * streambuf pointer passed to this constructor.
797 : */
798 : explicit
799 : basic_iostream(basic_streambuf<_CharT, _Traits>* __sb)
800 : : __istream_type(__sb), __ostream_type(__sb) { }
801 :
802 : /**
803 : * @brief Destructor does nothing.
804 : */
805 : virtual
806 0 : ~basic_iostream() { }
807 :
808 : protected:
809 0 : basic_iostream()
810 0 : : __istream_type(), __ostream_type() { }
811 : };
812 :
813 : // [27.6.1.4] standard basic_istream manipulators
814 : /**
815 : * @brief Quick and easy way to eat whitespace
816 : *
817 : * This manipulator extracts whitespace characters, stopping when the
818 : * next character is non-whitespace, or when the input sequence is empty.
819 : * If the sequence is empty, @c eofbit is set in the stream, but not
820 : * @c failbit.
821 : *
822 : * The current locale is used to distinguish whitespace characters.
823 : *
824 : * Example:
825 : * @code
826 : * MyClass mc;
827 : *
828 : * std::cin >> std::ws >> mc;
829 : * @endcode
830 : * will skip leading whitespace before calling operator>> on cin and your
831 : * object. Note that the same effect can be achieved by creating a
832 : * std::basic_istream::sentry inside your definition of operator>>.
833 : */
834 : template<typename _CharT, typename _Traits>
835 : basic_istream<_CharT, _Traits>&
836 : ws(basic_istream<_CharT, _Traits>& __is);
837 :
838 : #ifdef __GXX_EXPERIMENTAL_CXX0X__
839 : // [27.7.1.6] Rvalue stream extraction
840 : /**
841 : * @brief Generic extractor for rvalue stream
842 : * @param is An input stream.
843 : * @param x A reference to the extraction target.
844 : * @return is
845 : *
846 : * This is just a forwarding function to allow extraction from
847 : * rvalue streams since they won't bind to the extractor functions
848 : * that take an lvalue reference.
849 : */
850 : template<typename _CharT, typename _Traits, typename _Tp>
851 : inline basic_istream<_CharT, _Traits>&
852 : operator>>(basic_istream<_CharT, _Traits>&& __is, _Tp& __x)
853 : { return (__is >> __x); }
854 : #endif // __GXX_EXPERIMENTAL_CXX0X__
855 :
856 : _GLIBCXX_END_NAMESPACE_VERSION
857 : } // namespace
858 :
859 : #include <bits/istream.tcc>
860 :
861 : #endif /* _GLIBCXX_ISTREAM */
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