libstdc++
|
00001 // Input streams -*- C++ -*- 00002 00003 // Copyright (C) 1997-2013 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 template<typename _ValueT> 00611 __istream_type& 00612 _M_extract(_ValueT& __v); 00613 }; 00614 00615 /// Explicit specialization declarations, defined in src/istream.cc. 00616 template<> 00617 basic_istream<char>& 00618 basic_istream<char>:: 00619 getline(char_type* __s, streamsize __n, char_type __delim); 00620 00621 template<> 00622 basic_istream<char>& 00623 basic_istream<char>:: 00624 ignore(streamsize __n); 00625 00626 template<> 00627 basic_istream<char>& 00628 basic_istream<char>:: 00629 ignore(streamsize __n, int_type __delim); 00630 00631 #ifdef _GLIBCXX_USE_WCHAR_T 00632 template<> 00633 basic_istream<wchar_t>& 00634 basic_istream<wchar_t>:: 00635 getline(char_type* __s, streamsize __n, char_type __delim); 00636 00637 template<> 00638 basic_istream<wchar_t>& 00639 basic_istream<wchar_t>:: 00640 ignore(streamsize __n); 00641 00642 template<> 00643 basic_istream<wchar_t>& 00644 basic_istream<wchar_t>:: 00645 ignore(streamsize __n, int_type __delim); 00646 #endif 00647 00648 /** 00649 * @brief Performs setup work for input streams. 00650 * 00651 * Objects of this class are created before all of the standard 00652 * extractors are run. It is responsible for <em>exception-safe 00653 * prefix and suffix operations,</em> although only prefix actions 00654 * are currently required by the standard. 00655 */ 00656 template<typename _CharT, typename _Traits> 00657 class basic_istream<_CharT, _Traits>::sentry 00658 { 00659 // Data Members. 00660 bool _M_ok; 00661 00662 public: 00663 /// Easy access to dependent types. 00664 typedef _Traits traits_type; 00665 typedef basic_streambuf<_CharT, _Traits> __streambuf_type; 00666 typedef basic_istream<_CharT, _Traits> __istream_type; 00667 typedef typename __istream_type::__ctype_type __ctype_type; 00668 typedef typename _Traits::int_type __int_type; 00669 00670 /** 00671 * @brief The constructor performs all the work. 00672 * @param __is The input stream to guard. 00673 * @param __noskipws Whether to consume whitespace or not. 00674 * 00675 * If the stream state is good (@a __is.good() is true), then the 00676 * following actions are performed, otherwise the sentry state 00677 * is false (<em>not okay</em>) and failbit is set in the 00678 * stream state. 00679 * 00680 * The sentry's preparatory actions are: 00681 * 00682 * -# if the stream is tied to an output stream, @c is.tie()->flush() 00683 * is called to synchronize the output sequence 00684 * -# if @a __noskipws is false, and @c ios_base::skipws is set in 00685 * @c is.flags(), the sentry extracts and discards whitespace 00686 * characters from the stream. The currently imbued locale is 00687 * used to determine whether each character is whitespace. 00688 * 00689 * If the stream state is still good, then the sentry state becomes 00690 * true (@a okay). 00691 */ 00692 explicit 00693 sentry(basic_istream<_CharT, _Traits>& __is, bool __noskipws = false); 00694 00695 /** 00696 * @brief Quick status checking. 00697 * @return The sentry state. 00698 * 00699 * For ease of use, sentries may be converted to booleans. The 00700 * return value is that of the sentry state (true == okay). 00701 */ 00702 #if __cplusplus >= 201103L 00703 explicit 00704 #endif 00705 operator bool() const 00706 { return _M_ok; } 00707 }; 00708 00709 //@{ 00710 /** 00711 * @brief Character extractors 00712 * @param __in An input stream. 00713 * @param __c A character reference. 00714 * @return in 00715 * 00716 * Behaves like one of the formatted arithmetic extractors described in 00717 * std::basic_istream. After constructing a sentry object with good 00718 * status, this function extracts a character (if one is available) and 00719 * stores it in @a __c. Otherwise, sets failbit in the input stream. 00720 */ 00721 template<typename _CharT, typename _Traits> 00722 basic_istream<_CharT, _Traits>& 00723 operator>>(basic_istream<_CharT, _Traits>& __in, _CharT& __c); 00724 00725 template<class _Traits> 00726 inline basic_istream<char, _Traits>& 00727 operator>>(basic_istream<char, _Traits>& __in, unsigned char& __c) 00728 { return (__in >> reinterpret_cast<char&>(__c)); } 00729 00730 template<class _Traits> 00731 inline basic_istream<char, _Traits>& 00732 operator>>(basic_istream<char, _Traits>& __in, signed char& __c) 00733 { return (__in >> reinterpret_cast<char&>(__c)); } 00734 //@} 00735 00736 //@{ 00737 /** 00738 * @brief Character string extractors 00739 * @param __in An input stream. 00740 * @param __s A pointer to a character array. 00741 * @return __in 00742 * 00743 * Behaves like one of the formatted arithmetic extractors described in 00744 * std::basic_istream. After constructing a sentry object with good 00745 * status, this function extracts up to @c n characters and stores them 00746 * into the array starting at @a __s. @c n is defined as: 00747 * 00748 * - if @c width() is greater than zero, @c n is width() otherwise 00749 * - @c n is <em>the number of elements of the largest array of * 00750 * - @c char_type that can store a terminating @c eos.</em> 00751 * - [27.6.1.2.3]/6 00752 * 00753 * Characters are extracted and stored until one of the following happens: 00754 * - @c n-1 characters are stored 00755 * - EOF is reached 00756 * - the next character is whitespace according to the current locale 00757 * - the next character is a null byte (i.e., @c charT() ) 00758 * 00759 * @c width(0) is then called for the input stream. 00760 * 00761 * If no characters are extracted, sets failbit. 00762 */ 00763 template<typename _CharT, typename _Traits> 00764 basic_istream<_CharT, _Traits>& 00765 operator>>(basic_istream<_CharT, _Traits>& __in, _CharT* __s); 00766 00767 // Explicit specialization declaration, defined in src/istream.cc. 00768 template<> 00769 basic_istream<char>& 00770 operator>>(basic_istream<char>& __in, char* __s); 00771 00772 template<class _Traits> 00773 inline basic_istream<char, _Traits>& 00774 operator>>(basic_istream<char, _Traits>& __in, unsigned char* __s) 00775 { return (__in >> reinterpret_cast<char*>(__s)); } 00776 00777 template<class _Traits> 00778 inline basic_istream<char, _Traits>& 00779 operator>>(basic_istream<char, _Traits>& __in, signed char* __s) 00780 { return (__in >> reinterpret_cast<char*>(__s)); } 00781 //@} 00782 00783 /** 00784 * @brief Template class basic_iostream 00785 * @ingroup io 00786 * 00787 * @tparam _CharT Type of character stream. 00788 * @tparam _Traits Traits for character type, defaults to 00789 * char_traits<_CharT>. 00790 * 00791 * This class multiply inherits from the input and output stream classes 00792 * simply to provide a single interface. 00793 */ 00794 template<typename _CharT, typename _Traits> 00795 class basic_iostream 00796 : public basic_istream<_CharT, _Traits>, 00797 public basic_ostream<_CharT, _Traits> 00798 { 00799 public: 00800 // _GLIBCXX_RESOLVE_LIB_DEFECTS 00801 // 271. basic_iostream missing typedefs 00802 // Types (inherited): 00803 typedef _CharT char_type; 00804 typedef typename _Traits::int_type int_type; 00805 typedef typename _Traits::pos_type pos_type; 00806 typedef typename _Traits::off_type off_type; 00807 typedef _Traits traits_type; 00808 00809 // Non-standard Types: 00810 typedef basic_istream<_CharT, _Traits> __istream_type; 00811 typedef basic_ostream<_CharT, _Traits> __ostream_type; 00812 00813 /** 00814 * @brief Constructor does nothing. 00815 * 00816 * Both of the parent classes are initialized with the same 00817 * streambuf pointer passed to this constructor. 00818 */ 00819 explicit 00820 basic_iostream(basic_streambuf<_CharT, _Traits>* __sb) 00821 : __istream_type(__sb), __ostream_type(__sb) { } 00822 00823 /** 00824 * @brief Destructor does nothing. 00825 */ 00826 virtual 00827 ~basic_iostream() { } 00828 00829 protected: 00830 basic_iostream() 00831 : __istream_type(), __ostream_type() { } 00832 }; 00833 00834 /** 00835 * @brief Quick and easy way to eat whitespace 00836 * 00837 * This manipulator extracts whitespace characters, stopping when the 00838 * next character is non-whitespace, or when the input sequence is empty. 00839 * If the sequence is empty, @c eofbit is set in the stream, but not 00840 * @c failbit. 00841 * 00842 * The current locale is used to distinguish whitespace characters. 00843 * 00844 * Example: 00845 * @code 00846 * MyClass mc; 00847 * 00848 * std::cin >> std::ws >> mc; 00849 * @endcode 00850 * will skip leading whitespace before calling operator>> on cin and your 00851 * object. Note that the same effect can be achieved by creating a 00852 * std::basic_istream::sentry inside your definition of operator>>. 00853 */ 00854 template<typename _CharT, typename _Traits> 00855 basic_istream<_CharT, _Traits>& 00856 ws(basic_istream<_CharT, _Traits>& __is); 00857 00858 #if __cplusplus >= 201103L 00859 // [27.7.1.6] Rvalue stream extraction 00860 /** 00861 * @brief Generic extractor for rvalue stream 00862 * @param __is An input stream. 00863 * @param __x A reference to the extraction target. 00864 * @return is 00865 * 00866 * This is just a forwarding function to allow extraction from 00867 * rvalue streams since they won't bind to the extractor functions 00868 * that take an lvalue reference. 00869 */ 00870 template<typename _CharT, typename _Traits, typename _Tp> 00871 inline basic_istream<_CharT, _Traits>& 00872 operator>>(basic_istream<_CharT, _Traits>&& __is, _Tp& __x) 00873 { return (__is >> __x); } 00874 #endif // C++11 00875 00876 _GLIBCXX_END_NAMESPACE_VERSION 00877 } // namespace 00878 00879 #include <bits/istream.tcc> 00880 00881 #endif /* _GLIBCXX_ISTREAM */