libstdc++
|
00001 // Input streams -*- C++ -*- 00002 00003 // Copyright (C) 1997-2015 Free Software Foundation, Inc. 00004 // 00005 // This file is part of the GNU ISO C++ Library. This library is free 00006 // software; you can redistribute it and/or modify it under the 00007 // terms of the GNU General Public License as published by the 00008 // Free Software Foundation; either version 3, or (at your option) 00009 // any later version. 00010 00011 // This library is distributed in the hope that it will be useful, 00012 // but WITHOUT ANY WARRANTY; without even the implied warranty of 00013 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00014 // GNU General Public License for more details. 00015 00016 // Under Section 7 of GPL version 3, you are granted additional 00017 // permissions described in the GCC Runtime Library Exception, version 00018 // 3.1, as published by the Free Software Foundation. 00019 00020 // You should have received a copy of the GNU General Public License and 00021 // a copy of the GCC Runtime Library Exception along with this program; 00022 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 00023 // <http://www.gnu.org/licenses/>. 00024 00025 // 00026 // ISO C++ 14882: 27.6.1 Input streams 00027 // 00028 00029 /** @file include/istream 00030 * This is a Standard C++ Library header. 00031 */ 00032 00033 #ifndef _GLIBCXX_ISTREAM 00034 #define _GLIBCXX_ISTREAM 1 00035 00036 #pragma GCC system_header 00037 00038 #include <ios> 00039 #include <ostream> 00040 00041 namespace std _GLIBCXX_VISIBILITY(default) 00042 { 00043 _GLIBCXX_BEGIN_NAMESPACE_VERSION 00044 00045 /** 00046 * @brief Template class basic_istream. 00047 * @ingroup io 00048 * 00049 * @tparam _CharT Type of character stream. 00050 * @tparam _Traits Traits for character type, defaults to 00051 * char_traits<_CharT>. 00052 * 00053 * This is the base class for all input streams. It provides text 00054 * formatting of all builtin types, and communicates with any class 00055 * derived from basic_streambuf to do the actual input. 00056 */ 00057 template<typename _CharT, typename _Traits> 00058 class basic_istream : virtual public basic_ios<_CharT, _Traits> 00059 { 00060 public: 00061 // Types (inherited from basic_ios (27.4.4)): 00062 typedef _CharT char_type; 00063 typedef typename _Traits::int_type int_type; 00064 typedef typename _Traits::pos_type pos_type; 00065 typedef typename _Traits::off_type off_type; 00066 typedef _Traits traits_type; 00067 00068 // Non-standard Types: 00069 typedef basic_streambuf<_CharT, _Traits> __streambuf_type; 00070 typedef basic_ios<_CharT, _Traits> __ios_type; 00071 typedef basic_istream<_CharT, _Traits> __istream_type; 00072 typedef num_get<_CharT, istreambuf_iterator<_CharT, _Traits> > 00073 __num_get_type; 00074 typedef ctype<_CharT> __ctype_type; 00075 00076 protected: 00077 // Data Members: 00078 /** 00079 * The number of characters extracted in the previous unformatted 00080 * function; see gcount(). 00081 */ 00082 streamsize _M_gcount; 00083 00084 public: 00085 /** 00086 * @brief Base constructor. 00087 * 00088 * This ctor is almost never called by the user directly, rather from 00089 * derived classes' initialization lists, which pass a pointer to 00090 * their own stream buffer. 00091 */ 00092 explicit 00093 basic_istream(__streambuf_type* __sb) 00094 : _M_gcount(streamsize(0)) 00095 { this->init(__sb); } 00096 00097 /** 00098 * @brief Base destructor. 00099 * 00100 * This does very little apart from providing a virtual base dtor. 00101 */ 00102 virtual 00103 ~basic_istream() 00104 { _M_gcount = streamsize(0); } 00105 00106 /// Safe prefix/suffix operations. 00107 class sentry; 00108 friend class sentry; 00109 00110 //@{ 00111 /** 00112 * @brief Interface for manipulators. 00113 * 00114 * Manipulators such as @c std::ws and @c std::dec use these 00115 * functions in constructs like 00116 * <code>std::cin >> std::ws</code>. 00117 * For more information, see the iomanip header. 00118 */ 00119 __istream_type& 00120 operator>>(__istream_type& (*__pf)(__istream_type&)) 00121 { return __pf(*this); } 00122 00123 __istream_type& 00124 operator>>(__ios_type& (*__pf)(__ios_type&)) 00125 { 00126 __pf(*this); 00127 return *this; 00128 } 00129 00130 __istream_type& 00131 operator>>(ios_base& (*__pf)(ios_base&)) 00132 { 00133 __pf(*this); 00134 return *this; 00135 } 00136 //@} 00137 00138 //@{ 00139 /** 00140 * @name Extractors 00141 * 00142 * All the @c operator>> functions (aka <em>formatted input 00143 * functions</em>) have some common behavior. Each starts by 00144 * constructing a temporary object of type std::basic_istream::sentry 00145 * with the second argument (noskipws) set to false. This has several 00146 * effects, concluding with the setting of a status flag; see the 00147 * sentry documentation for more. 00148 * 00149 * If the sentry status is good, the function tries to extract 00150 * whatever data is appropriate for the type of the argument. 00151 * 00152 * If an exception is thrown during extraction, ios_base::badbit 00153 * will be turned on in the stream's error state without causing an 00154 * ios_base::failure to be thrown. The original exception will then 00155 * be rethrown. 00156 */ 00157 00158 //@{ 00159 /** 00160 * @brief Integer arithmetic extractors 00161 * @param __n A variable of builtin integral type. 00162 * @return @c *this if successful 00163 * 00164 * These functions use the stream's current locale (specifically, the 00165 * @c num_get facet) to parse the input data. 00166 */ 00167 __istream_type& 00168 operator>>(bool& __n) 00169 { return _M_extract(__n); } 00170 00171 __istream_type& 00172 operator>>(short& __n); 00173 00174 __istream_type& 00175 operator>>(unsigned short& __n) 00176 { return _M_extract(__n); } 00177 00178 __istream_type& 00179 operator>>(int& __n); 00180 00181 __istream_type& 00182 operator>>(unsigned int& __n) 00183 { return _M_extract(__n); } 00184 00185 __istream_type& 00186 operator>>(long& __n) 00187 { return _M_extract(__n); } 00188 00189 __istream_type& 00190 operator>>(unsigned long& __n) 00191 { return _M_extract(__n); } 00192 00193 #ifdef _GLIBCXX_USE_LONG_LONG 00194 __istream_type& 00195 operator>>(long long& __n) 00196 { return _M_extract(__n); } 00197 00198 __istream_type& 00199 operator>>(unsigned long long& __n) 00200 { return _M_extract(__n); } 00201 #endif 00202 //@} 00203 00204 //@{ 00205 /** 00206 * @brief Floating point arithmetic extractors 00207 * @param __f A variable of builtin floating point type. 00208 * @return @c *this if successful 00209 * 00210 * These functions use the stream's current locale (specifically, the 00211 * @c num_get facet) to parse the input data. 00212 */ 00213 __istream_type& 00214 operator>>(float& __f) 00215 { return _M_extract(__f); } 00216 00217 __istream_type& 00218 operator>>(double& __f) 00219 { return _M_extract(__f); } 00220 00221 __istream_type& 00222 operator>>(long double& __f) 00223 { return _M_extract(__f); } 00224 //@} 00225 00226 /** 00227 * @brief Basic arithmetic extractors 00228 * @param __p A variable of pointer type. 00229 * @return @c *this if successful 00230 * 00231 * These functions use the stream's current locale (specifically, the 00232 * @c num_get facet) to parse the input data. 00233 */ 00234 __istream_type& 00235 operator>>(void*& __p) 00236 { return _M_extract(__p); } 00237 00238 /** 00239 * @brief Extracting into another streambuf. 00240 * @param __sb A pointer to a streambuf 00241 * 00242 * This function behaves like one of the basic arithmetic extractors, 00243 * in that it also constructs a sentry object and has the same error 00244 * handling behavior. 00245 * 00246 * If @p __sb is NULL, the stream will set failbit in its error state. 00247 * 00248 * Characters are extracted from this stream and inserted into the 00249 * @p __sb streambuf until one of the following occurs: 00250 * 00251 * - the input stream reaches end-of-file, 00252 * - insertion into the output buffer fails (in this case, the 00253 * character that would have been inserted is not extracted), or 00254 * - an exception occurs (and in this case is caught) 00255 * 00256 * If the function inserts no characters, failbit is set. 00257 */ 00258 __istream_type& 00259 operator>>(__streambuf_type* __sb); 00260 //@} 00261 00262 // [27.6.1.3] unformatted input 00263 /** 00264 * @brief Character counting 00265 * @return The number of characters extracted by the previous 00266 * unformatted input function dispatched for this stream. 00267 */ 00268 streamsize 00269 gcount() const 00270 { return _M_gcount; } 00271 00272 //@{ 00273 /** 00274 * @name Unformatted Input Functions 00275 * 00276 * All the unformatted input functions have some common behavior. 00277 * Each starts by constructing a temporary object of type 00278 * std::basic_istream::sentry with the second argument (noskipws) 00279 * set to true. This has several effects, concluding with the 00280 * setting of a status flag; see the sentry documentation for more. 00281 * 00282 * If the sentry status is good, the function tries to extract 00283 * whatever data is appropriate for the type of the argument. 00284 * 00285 * The number of characters extracted is stored for later retrieval 00286 * by gcount(). 00287 * 00288 * If an exception is thrown during extraction, ios_base::badbit 00289 * will be turned on in the stream's error state without causing an 00290 * ios_base::failure to be thrown. The original exception will then 00291 * be rethrown. 00292 */ 00293 00294 /** 00295 * @brief Simple extraction. 00296 * @return A character, or eof(). 00297 * 00298 * Tries to extract a character. If none are available, sets failbit 00299 * and returns traits::eof(). 00300 */ 00301 int_type 00302 get(); 00303 00304 /** 00305 * @brief Simple extraction. 00306 * @param __c The character in which to store data. 00307 * @return *this 00308 * 00309 * Tries to extract a character and store it in @a __c. If none are 00310 * available, sets failbit and returns traits::eof(). 00311 * 00312 * @note This function is not overloaded on signed char and 00313 * unsigned char. 00314 */ 00315 __istream_type& 00316 get(char_type& __c); 00317 00318 /** 00319 * @brief Simple multiple-character extraction. 00320 * @param __s Pointer to an array. 00321 * @param __n Maximum number of characters to store in @a __s. 00322 * @param __delim A "stop" character. 00323 * @return *this 00324 * 00325 * Characters are extracted and stored into @a __s until one of the 00326 * following happens: 00327 * 00328 * - @c __n-1 characters are stored 00329 * - the input sequence reaches EOF 00330 * - the next character equals @a __delim, in which case the character 00331 * is not extracted 00332 * 00333 * If no characters are stored, failbit is set in the stream's error 00334 * state. 00335 * 00336 * In any case, a null character is stored into the next location in 00337 * the array. 00338 * 00339 * @note This function is not overloaded on signed char and 00340 * unsigned char. 00341 */ 00342 __istream_type& 00343 get(char_type* __s, streamsize __n, char_type __delim); 00344 00345 /** 00346 * @brief Simple multiple-character extraction. 00347 * @param __s Pointer to an array. 00348 * @param __n Maximum number of characters to store in @a s. 00349 * @return *this 00350 * 00351 * Returns @c get(__s,__n,widen('\\n')). 00352 */ 00353 __istream_type& 00354 get(char_type* __s, streamsize __n) 00355 { return this->get(__s, __n, this->widen('\n')); } 00356 00357 /** 00358 * @brief Extraction into another streambuf. 00359 * @param __sb A streambuf in which to store data. 00360 * @param __delim A "stop" character. 00361 * @return *this 00362 * 00363 * Characters are extracted and inserted into @a __sb until one of the 00364 * following happens: 00365 * 00366 * - the input sequence reaches EOF 00367 * - insertion into the output buffer fails (in this case, the 00368 * character that would have been inserted is not extracted) 00369 * - the next character equals @a __delim (in this case, the character 00370 * is not extracted) 00371 * - an exception occurs (and in this case is caught) 00372 * 00373 * If no characters are stored, failbit is set in the stream's error 00374 * state. 00375 */ 00376 __istream_type& 00377 get(__streambuf_type& __sb, char_type __delim); 00378 00379 /** 00380 * @brief Extraction into another streambuf. 00381 * @param __sb A streambuf in which to store data. 00382 * @return *this 00383 * 00384 * Returns @c get(__sb,widen('\\n')). 00385 */ 00386 __istream_type& 00387 get(__streambuf_type& __sb) 00388 { return this->get(__sb, this->widen('\n')); } 00389 00390 /** 00391 * @brief String extraction. 00392 * @param __s A character array in which to store the data. 00393 * @param __n Maximum number of characters to extract. 00394 * @param __delim A "stop" character. 00395 * @return *this 00396 * 00397 * Extracts and stores characters into @a __s until one of the 00398 * following happens. Note that these criteria are required to be 00399 * tested in the order listed here, to allow an input line to exactly 00400 * fill the @a __s array without setting failbit. 00401 * 00402 * -# the input sequence reaches end-of-file, in which case eofbit 00403 * is set in the stream error state 00404 * -# the next character equals @c __delim, in which case the character 00405 * is extracted (and therefore counted in @c gcount()) but not stored 00406 * -# @c __n-1 characters are stored, in which case failbit is set 00407 * in the stream error state 00408 * 00409 * If no characters are extracted, failbit is set. (An empty line of 00410 * input should therefore not cause failbit to be set.) 00411 * 00412 * In any case, a null character is stored in the next location in 00413 * the array. 00414 */ 00415 __istream_type& 00416 getline(char_type* __s, streamsize __n, char_type __delim); 00417 00418 /** 00419 * @brief String extraction. 00420 * @param __s A character array in which to store the data. 00421 * @param __n Maximum number of characters to extract. 00422 * @return *this 00423 * 00424 * Returns @c getline(__s,__n,widen('\\n')). 00425 */ 00426 __istream_type& 00427 getline(char_type* __s, streamsize __n) 00428 { return this->getline(__s, __n, this->widen('\n')); } 00429 00430 /** 00431 * @brief Discarding characters 00432 * @param __n Number of characters to discard. 00433 * @param __delim A "stop" character. 00434 * @return *this 00435 * 00436 * Extracts characters and throws them away until one of the 00437 * following happens: 00438 * - if @a __n @c != @c std::numeric_limits<int>::max(), @a __n 00439 * characters are extracted 00440 * - the input sequence reaches end-of-file 00441 * - the next character equals @a __delim (in this case, the character 00442 * is extracted); note that this condition will never occur if 00443 * @a __delim equals @c traits::eof(). 00444 * 00445 * NB: Provide three overloads, instead of the single function 00446 * (with defaults) mandated by the Standard: this leads to a 00447 * better performing implementation, while still conforming to 00448 * the Standard. 00449 */ 00450 __istream_type& 00451 ignore(streamsize __n, int_type __delim); 00452 00453 __istream_type& 00454 ignore(streamsize __n); 00455 00456 __istream_type& 00457 ignore(); 00458 00459 /** 00460 * @brief Looking ahead in the stream 00461 * @return The next character, or eof(). 00462 * 00463 * If, after constructing the sentry object, @c good() is false, 00464 * returns @c traits::eof(). Otherwise reads but does not extract 00465 * the next input character. 00466 */ 00467 int_type 00468 peek(); 00469 00470 /** 00471 * @brief Extraction without delimiters. 00472 * @param __s A character array. 00473 * @param __n Maximum number of characters to store. 00474 * @return *this 00475 * 00476 * If the stream state is @c good(), extracts characters and stores 00477 * them into @a __s until one of the following happens: 00478 * - @a __n characters are stored 00479 * - the input sequence reaches end-of-file, in which case the error 00480 * state is set to @c failbit|eofbit. 00481 * 00482 * @note This function is not overloaded on signed char and 00483 * unsigned char. 00484 */ 00485 __istream_type& 00486 read(char_type* __s, streamsize __n); 00487 00488 /** 00489 * @brief Extraction until the buffer is exhausted, but no more. 00490 * @param __s A character array. 00491 * @param __n Maximum number of characters to store. 00492 * @return The number of characters extracted. 00493 * 00494 * Extracts characters and stores them into @a __s depending on the 00495 * number of characters remaining in the streambuf's buffer, 00496 * @c rdbuf()->in_avail(), called @c A here: 00497 * - if @c A @c == @c -1, sets eofbit and extracts no characters 00498 * - if @c A @c == @c 0, extracts no characters 00499 * - if @c A @c > @c 0, extracts @c min(A,n) 00500 * 00501 * The goal is to empty the current buffer, and to not request any 00502 * more from the external input sequence controlled by the streambuf. 00503 */ 00504 streamsize 00505 readsome(char_type* __s, streamsize __n); 00506 00507 /** 00508 * @brief Unextracting a single character. 00509 * @param __c The character to push back into the input stream. 00510 * @return *this 00511 * 00512 * If @c rdbuf() is not null, calls @c rdbuf()->sputbackc(c). 00513 * 00514 * If @c rdbuf() is null or if @c sputbackc() fails, sets badbit in 00515 * the error state. 00516 * 00517 * @note This function first clears eofbit. Since no characters 00518 * are extracted, the next call to @c gcount() will return 0, 00519 * as required by DR 60. 00520 */ 00521 __istream_type& 00522 putback(char_type __c); 00523 00524 /** 00525 * @brief Unextracting the previous character. 00526 * @return *this 00527 * 00528 * If @c rdbuf() is not null, calls @c rdbuf()->sungetc(c). 00529 * 00530 * If @c rdbuf() is null or if @c sungetc() fails, sets badbit in 00531 * the error state. 00532 * 00533 * @note This function first clears eofbit. Since no characters 00534 * are extracted, the next call to @c gcount() will return 0, 00535 * as required by DR 60. 00536 */ 00537 __istream_type& 00538 unget(); 00539 00540 /** 00541 * @brief Synchronizing the stream buffer. 00542 * @return 0 on success, -1 on failure 00543 * 00544 * If @c rdbuf() is a null pointer, returns -1. 00545 * 00546 * Otherwise, calls @c rdbuf()->pubsync(), and if that returns -1, 00547 * sets badbit and returns -1. 00548 * 00549 * Otherwise, returns 0. 00550 * 00551 * @note This function does not count the number of characters 00552 * extracted, if any, and therefore does not affect the next 00553 * call to @c gcount(). 00554 */ 00555 int 00556 sync(); 00557 00558 /** 00559 * @brief Getting the current read position. 00560 * @return A file position object. 00561 * 00562 * If @c fail() is not false, returns @c pos_type(-1) to indicate 00563 * failure. Otherwise returns @c rdbuf()->pubseekoff(0,cur,in). 00564 * 00565 * @note This function does not count the number of characters 00566 * extracted, if any, and therefore does not affect the next 00567 * call to @c gcount(). At variance with putback, unget and 00568 * seekg, eofbit is not cleared first. 00569 */ 00570 pos_type 00571 tellg(); 00572 00573 /** 00574 * @brief Changing the current read position. 00575 * @param __pos A file position object. 00576 * @return *this 00577 * 00578 * If @c fail() is not true, calls @c rdbuf()->pubseekpos(__pos). If 00579 * that function fails, sets failbit. 00580 * 00581 * @note This function first clears eofbit. It does not count the 00582 * number of characters extracted, if any, and therefore does 00583 * not affect the next call to @c gcount(). 00584 */ 00585 __istream_type& 00586 seekg(pos_type); 00587 00588 /** 00589 * @brief Changing the current read position. 00590 * @param __off A file offset object. 00591 * @param __dir The direction in which to seek. 00592 * @return *this 00593 * 00594 * If @c fail() is not true, calls @c rdbuf()->pubseekoff(__off,__dir). 00595 * If that function fails, sets failbit. 00596 * 00597 * @note This function first clears eofbit. It does not count the 00598 * number of characters extracted, if any, and therefore does 00599 * not affect the next call to @c gcount(). 00600 */ 00601 __istream_type& 00602 seekg(off_type, ios_base::seekdir); 00603 //@} 00604 00605 protected: 00606 basic_istream() 00607 : _M_gcount(streamsize(0)) 00608 { this->init(0); } 00609 00610 #if __cplusplus >= 201103L 00611 basic_istream(const basic_istream&) = delete; 00612 00613 basic_istream(basic_istream&& __rhs) 00614 : __ios_type(), _M_gcount(__rhs._M_gcount) 00615 { 00616 __ios_type::move(__rhs); 00617 __rhs._M_gcount = 0; 00618 } 00619 00620 // 27.7.3.3 Assign/swap 00621 00622 basic_istream& operator=(const basic_istream&) = delete; 00623 00624 basic_istream& 00625 operator=(basic_istream&& __rhs) 00626 { 00627 swap(__rhs); 00628 return *this; 00629 } 00630 00631 void 00632 swap(basic_istream& __rhs) 00633 { 00634 __ios_type::swap(__rhs); 00635 std::swap(_M_gcount, __rhs._M_gcount); 00636 } 00637 #endif 00638 00639 template<typename _ValueT> 00640 __istream_type& 00641 _M_extract(_ValueT& __v); 00642 }; 00643 00644 /// Explicit specialization declarations, defined in src/istream.cc. 00645 template<> 00646 basic_istream<char>& 00647 basic_istream<char>:: 00648 getline(char_type* __s, streamsize __n, char_type __delim); 00649 00650 template<> 00651 basic_istream<char>& 00652 basic_istream<char>:: 00653 ignore(streamsize __n); 00654 00655 template<> 00656 basic_istream<char>& 00657 basic_istream<char>:: 00658 ignore(streamsize __n, int_type __delim); 00659 00660 #ifdef _GLIBCXX_USE_WCHAR_T 00661 template<> 00662 basic_istream<wchar_t>& 00663 basic_istream<wchar_t>:: 00664 getline(char_type* __s, streamsize __n, char_type __delim); 00665 00666 template<> 00667 basic_istream<wchar_t>& 00668 basic_istream<wchar_t>:: 00669 ignore(streamsize __n); 00670 00671 template<> 00672 basic_istream<wchar_t>& 00673 basic_istream<wchar_t>:: 00674 ignore(streamsize __n, int_type __delim); 00675 #endif 00676 00677 /** 00678 * @brief Performs setup work for input streams. 00679 * 00680 * Objects of this class are created before all of the standard 00681 * extractors are run. It is responsible for <em>exception-safe 00682 * prefix and suffix operations,</em> although only prefix actions 00683 * are currently required by the standard. 00684 */ 00685 template<typename _CharT, typename _Traits> 00686 class basic_istream<_CharT, _Traits>::sentry 00687 { 00688 // Data Members. 00689 bool _M_ok; 00690 00691 public: 00692 /// Easy access to dependent types. 00693 typedef _Traits traits_type; 00694 typedef basic_streambuf<_CharT, _Traits> __streambuf_type; 00695 typedef basic_istream<_CharT, _Traits> __istream_type; 00696 typedef typename __istream_type::__ctype_type __ctype_type; 00697 typedef typename _Traits::int_type __int_type; 00698 00699 /** 00700 * @brief The constructor performs all the work. 00701 * @param __is The input stream to guard. 00702 * @param __noskipws Whether to consume whitespace or not. 00703 * 00704 * If the stream state is good (@a __is.good() is true), then the 00705 * following actions are performed, otherwise the sentry state 00706 * is false (<em>not okay</em>) and failbit is set in the 00707 * stream state. 00708 * 00709 * The sentry's preparatory actions are: 00710 * 00711 * -# if the stream is tied to an output stream, @c is.tie()->flush() 00712 * is called to synchronize the output sequence 00713 * -# if @a __noskipws is false, and @c ios_base::skipws is set in 00714 * @c is.flags(), the sentry extracts and discards whitespace 00715 * characters from the stream. The currently imbued locale is 00716 * used to determine whether each character is whitespace. 00717 * 00718 * If the stream state is still good, then the sentry state becomes 00719 * true (@a okay). 00720 */ 00721 explicit 00722 sentry(basic_istream<_CharT, _Traits>& __is, bool __noskipws = false); 00723 00724 /** 00725 * @brief Quick status checking. 00726 * @return The sentry state. 00727 * 00728 * For ease of use, sentries may be converted to booleans. The 00729 * return value is that of the sentry state (true == okay). 00730 */ 00731 #if __cplusplus >= 201103L 00732 explicit 00733 #endif 00734 operator bool() const 00735 { return _M_ok; } 00736 }; 00737 00738 //@{ 00739 /** 00740 * @brief Character extractors 00741 * @param __in An input stream. 00742 * @param __c A character reference. 00743 * @return in 00744 * 00745 * Behaves like one of the formatted arithmetic extractors described in 00746 * std::basic_istream. After constructing a sentry object with good 00747 * status, this function extracts a character (if one is available) and 00748 * stores it in @a __c. Otherwise, sets failbit in the input stream. 00749 */ 00750 template<typename _CharT, typename _Traits> 00751 basic_istream<_CharT, _Traits>& 00752 operator>>(basic_istream<_CharT, _Traits>& __in, _CharT& __c); 00753 00754 template<class _Traits> 00755 inline basic_istream<char, _Traits>& 00756 operator>>(basic_istream<char, _Traits>& __in, unsigned char& __c) 00757 { return (__in >> reinterpret_cast<char&>(__c)); } 00758 00759 template<class _Traits> 00760 inline basic_istream<char, _Traits>& 00761 operator>>(basic_istream<char, _Traits>& __in, signed char& __c) 00762 { return (__in >> reinterpret_cast<char&>(__c)); } 00763 //@} 00764 00765 //@{ 00766 /** 00767 * @brief Character string extractors 00768 * @param __in An input stream. 00769 * @param __s A pointer to a character array. 00770 * @return __in 00771 * 00772 * Behaves like one of the formatted arithmetic extractors described in 00773 * std::basic_istream. After constructing a sentry object with good 00774 * status, this function extracts up to @c n characters and stores them 00775 * into the array starting at @a __s. @c n is defined as: 00776 * 00777 * - if @c width() is greater than zero, @c n is width() otherwise 00778 * - @c n is <em>the number of elements of the largest array of * 00779 * - @c char_type that can store a terminating @c eos.</em> 00780 * - [27.6.1.2.3]/6 00781 * 00782 * Characters are extracted and stored until one of the following happens: 00783 * - @c n-1 characters are stored 00784 * - EOF is reached 00785 * - the next character is whitespace according to the current locale 00786 * - the next character is a null byte (i.e., @c charT() ) 00787 * 00788 * @c width(0) is then called for the input stream. 00789 * 00790 * If no characters are extracted, sets failbit. 00791 */ 00792 template<typename _CharT, typename _Traits> 00793 basic_istream<_CharT, _Traits>& 00794 operator>>(basic_istream<_CharT, _Traits>& __in, _CharT* __s); 00795 00796 // Explicit specialization declaration, defined in src/istream.cc. 00797 template<> 00798 basic_istream<char>& 00799 operator>>(basic_istream<char>& __in, char* __s); 00800 00801 template<class _Traits> 00802 inline basic_istream<char, _Traits>& 00803 operator>>(basic_istream<char, _Traits>& __in, unsigned char* __s) 00804 { return (__in >> reinterpret_cast<char*>(__s)); } 00805 00806 template<class _Traits> 00807 inline basic_istream<char, _Traits>& 00808 operator>>(basic_istream<char, _Traits>& __in, signed char* __s) 00809 { return (__in >> reinterpret_cast<char*>(__s)); } 00810 //@} 00811 00812 /** 00813 * @brief Template class basic_iostream 00814 * @ingroup io 00815 * 00816 * @tparam _CharT Type of character stream. 00817 * @tparam _Traits Traits for character type, defaults to 00818 * char_traits<_CharT>. 00819 * 00820 * This class multiply inherits from the input and output stream classes 00821 * simply to provide a single interface. 00822 */ 00823 template<typename _CharT, typename _Traits> 00824 class basic_iostream 00825 : public basic_istream<_CharT, _Traits>, 00826 public basic_ostream<_CharT, _Traits> 00827 { 00828 public: 00829 // _GLIBCXX_RESOLVE_LIB_DEFECTS 00830 // 271. basic_iostream missing typedefs 00831 // Types (inherited): 00832 typedef _CharT char_type; 00833 typedef typename _Traits::int_type int_type; 00834 typedef typename _Traits::pos_type pos_type; 00835 typedef typename _Traits::off_type off_type; 00836 typedef _Traits traits_type; 00837 00838 // Non-standard Types: 00839 typedef basic_istream<_CharT, _Traits> __istream_type; 00840 typedef basic_ostream<_CharT, _Traits> __ostream_type; 00841 00842 /** 00843 * @brief Constructor does nothing. 00844 * 00845 * Both of the parent classes are initialized with the same 00846 * streambuf pointer passed to this constructor. 00847 */ 00848 explicit 00849 basic_iostream(basic_streambuf<_CharT, _Traits>* __sb) 00850 : __istream_type(__sb), __ostream_type(__sb) { } 00851 00852 /** 00853 * @brief Destructor does nothing. 00854 */ 00855 virtual 00856 ~basic_iostream() { } 00857 00858 protected: 00859 basic_iostream() 00860 : __istream_type(), __ostream_type() { } 00861 00862 #if __cplusplus >= 201103L 00863 basic_iostream(const basic_iostream&) = delete; 00864 00865 basic_iostream(basic_iostream&& __rhs) 00866 : __istream_type(std::move(__rhs)), __ostream_type(*this) 00867 { } 00868 00869 // 27.7.3.3 Assign/swap 00870 00871 basic_iostream& operator=(const basic_iostream&) = delete; 00872 00873 basic_iostream& 00874 operator=(basic_iostream&& __rhs) 00875 { 00876 swap(__rhs); 00877 return *this; 00878 } 00879 00880 void 00881 swap(basic_iostream& __rhs) 00882 { __istream_type::swap(__rhs); } 00883 #endif 00884 }; 00885 00886 /** 00887 * @brief Quick and easy way to eat whitespace 00888 * 00889 * This manipulator extracts whitespace characters, stopping when the 00890 * next character is non-whitespace, or when the input sequence is empty. 00891 * If the sequence is empty, @c eofbit is set in the stream, but not 00892 * @c failbit. 00893 * 00894 * The current locale is used to distinguish whitespace characters. 00895 * 00896 * Example: 00897 * @code 00898 * MyClass mc; 00899 * 00900 * std::cin >> std::ws >> mc; 00901 * @endcode 00902 * will skip leading whitespace before calling operator>> on cin and your 00903 * object. Note that the same effect can be achieved by creating a 00904 * std::basic_istream::sentry inside your definition of operator>>. 00905 */ 00906 template<typename _CharT, typename _Traits> 00907 basic_istream<_CharT, _Traits>& 00908 ws(basic_istream<_CharT, _Traits>& __is); 00909 00910 #if __cplusplus >= 201103L 00911 // [27.7.1.6] Rvalue stream extraction 00912 /** 00913 * @brief Generic extractor for rvalue stream 00914 * @param __is An input stream. 00915 * @param __x A reference to the extraction target. 00916 * @return is 00917 * 00918 * This is just a forwarding function to allow extraction from 00919 * rvalue streams since they won't bind to the extractor functions 00920 * that take an lvalue reference. 00921 */ 00922 template<typename _CharT, typename _Traits, typename _Tp> 00923 inline basic_istream<_CharT, _Traits>& 00924 operator>>(basic_istream<_CharT, _Traits>&& __is, _Tp& __x) 00925 { 00926 __is >> __x; 00927 return __is; 00928 } 00929 #endif // C++11 00930 00931 _GLIBCXX_END_NAMESPACE_VERSION 00932 } // namespace 00933 00934 #include <bits/istream.tcc> 00935 00936 #endif /* _GLIBCXX_ISTREAM */