00001 // Input streams -*- C++ -*- 00002 00003 // Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 00004 // 2006, 2007, 2008, 2009, 2010 00005 // Free Software Foundation, Inc. 00006 // 00007 // This file is part of the GNU ISO C++ Library. This library is free 00008 // software; you can redistribute it and/or modify it under the 00009 // terms of the GNU General Public License as published by the 00010 // Free Software Foundation; either version 3, or (at your option) 00011 // any later version. 00012 00013 // This library is distributed in the hope that it will be useful, 00014 // but WITHOUT ANY WARRANTY; without even the implied warranty of 00015 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00016 // GNU General Public License for more details. 00017 00018 // Under Section 7 of GPL version 3, you are granted additional 00019 // permissions described in the GCC Runtime Library Exception, version 00020 // 3.1, as published by the Free Software Foundation. 00021 00022 // You should have received a copy of the GNU General Public License and 00023 // a copy of the GCC Runtime Library Exception along with this program; 00024 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 00025 // <http://www.gnu.org/licenses/>. 00026 00027 // 00028 // ISO C++ 14882: 27.6.1 Input streams 00029 // 00030 00031 /** @file istream 00032 * This is a Standard C++ Library header. 00033 */ 00034 00035 #ifndef _GLIBCXX_ISTREAM 00036 #define _GLIBCXX_ISTREAM 1 00037 00038 #pragma GCC system_header 00039 00040 #include <ios> 00041 #include <ostream> 00042 00043 _GLIBCXX_BEGIN_NAMESPACE(std) 00044 00045 // [27.6.1.1] Template class basic_istream 00046 /** 00047 * @brief Controlling input. 00048 * @ingroup io 00049 * 00050 * This is the base class for all input streams. It provides text 00051 * formatting of all builtin types, and communicates with any class 00052 * derived from basic_streambuf to do the actual input. 00053 */ 00054 template<typename _CharT, typename _Traits> 00055 class basic_istream : virtual public basic_ios<_CharT, _Traits> 00056 { 00057 public: 00058 // Types (inherited from basic_ios (27.4.4)): 00059 typedef _CharT char_type; 00060 typedef typename _Traits::int_type int_type; 00061 typedef typename _Traits::pos_type pos_type; 00062 typedef typename _Traits::off_type off_type; 00063 typedef _Traits traits_type; 00064 00065 // Non-standard Types: 00066 typedef basic_streambuf<_CharT, _Traits> __streambuf_type; 00067 typedef basic_ios<_CharT, _Traits> __ios_type; 00068 typedef basic_istream<_CharT, _Traits> __istream_type; 00069 typedef num_get<_CharT, istreambuf_iterator<_CharT, _Traits> > 00070 __num_get_type; 00071 typedef ctype<_CharT> __ctype_type; 00072 00073 protected: 00074 // Data Members: 00075 /** 00076 * The number of characters extracted in the previous unformatted 00077 * function; see gcount(). 00078 */ 00079 streamsize _M_gcount; 00080 00081 public: 00082 // [27.6.1.1.1] constructor/destructor 00083 /** 00084 * @brief Base constructor. 00085 * 00086 * This ctor is almost never called by the user directly, rather from 00087 * derived classes' initialization lists, which pass a pointer to 00088 * their own stream buffer. 00089 */ 00090 explicit 00091 basic_istream(__streambuf_type* __sb) 00092 : _M_gcount(streamsize(0)) 00093 { this->init(__sb); } 00094 00095 /** 00096 * @brief Base destructor. 00097 * 00098 * This does very little apart from providing a virtual base dtor. 00099 */ 00100 virtual 00101 ~basic_istream() 00102 { _M_gcount = streamsize(0); } 00103 00104 // [27.6.1.1.2] prefix/suffix 00105 class sentry; 00106 friend class sentry; 00107 00108 // [27.6.1.2] formatted input 00109 // [27.6.1.2.3] basic_istream::operator>> 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 // [27.6.1.2.2] arithmetic extractors 00139 /** 00140 * @name Arithmetic 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 * @brief Basic arithmetic extractors 00160 * @param A variable of builtin type. 00161 * @return @c *this if successful 00162 * 00163 * These functions use the stream's current locale (specifically, the 00164 * @c num_get facet) to parse the input data. 00165 */ 00166 __istream_type& 00167 operator>>(bool& __n) 00168 { return _M_extract(__n); } 00169 00170 __istream_type& 00171 operator>>(short& __n); 00172 00173 __istream_type& 00174 operator>>(unsigned short& __n) 00175 { return _M_extract(__n); } 00176 00177 __istream_type& 00178 operator>>(int& __n); 00179 00180 __istream_type& 00181 operator>>(unsigned int& __n) 00182 { return _M_extract(__n); } 00183 00184 __istream_type& 00185 operator>>(long& __n) 00186 { return _M_extract(__n); } 00187 00188 __istream_type& 00189 operator>>(unsigned long& __n) 00190 { return _M_extract(__n); } 00191 00192 #ifdef _GLIBCXX_USE_LONG_LONG 00193 __istream_type& 00194 operator>>(long long& __n) 00195 { return _M_extract(__n); } 00196 00197 __istream_type& 00198 operator>>(unsigned long long& __n) 00199 { return _M_extract(__n); } 00200 #endif 00201 00202 __istream_type& 00203 operator>>(float& __f) 00204 { return _M_extract(__f); } 00205 00206 __istream_type& 00207 operator>>(double& __f) 00208 { return _M_extract(__f); } 00209 00210 __istream_type& 00211 operator>>(long double& __f) 00212 { return _M_extract(__f); } 00213 00214 __istream_type& 00215 operator>>(void*& __p) 00216 { return _M_extract(__p); } 00217 00218 /** 00219 * @brief Extracting into another streambuf. 00220 * @param sb A pointer to a streambuf 00221 * 00222 * This function behaves like one of the basic arithmetic extractors, 00223 * in that it also constructs a sentry object and has the same error 00224 * handling behavior. 00225 * 00226 * If @a sb is NULL, the stream will set failbit in its error state. 00227 * 00228 * Characters are extracted from this stream and inserted into the 00229 * @a sb streambuf until one of the following occurs: 00230 * 00231 * - the input stream reaches end-of-file, 00232 * - insertion into the output buffer fails (in this case, the 00233 * character that would have been inserted is not extracted), or 00234 * - an exception occurs (and in this case is caught) 00235 * 00236 * If the function inserts no characters, failbit is set. 00237 */ 00238 __istream_type& 00239 operator>>(__streambuf_type* __sb); 00240 //@} 00241 00242 // [27.6.1.3] unformatted input 00243 /** 00244 * @brief Character counting 00245 * @return The number of characters extracted by the previous 00246 * unformatted input function dispatched for this stream. 00247 */ 00248 streamsize 00249 gcount() const 00250 { return _M_gcount; } 00251 00252 /** 00253 * @name Unformatted Input Functions 00254 * 00255 * All the unformatted input functions have some common behavior. 00256 * Each starts by constructing a temporary object of type 00257 * std::basic_istream::sentry with the second argument (noskipws) 00258 * set to true. This has several effects, concluding with the 00259 * setting of a status flag; see the sentry documentation for more. 00260 * 00261 * If the sentry status is good, the function tries to extract 00262 * whatever data is appropriate for the type of the argument. 00263 * 00264 * The number of characters extracted is stored for later retrieval 00265 * by gcount(). 00266 * 00267 * If an exception is thrown during extraction, ios_base::badbit 00268 * will be turned on in the stream's error state without causing an 00269 * ios_base::failure to be thrown. The original exception will then 00270 * be rethrown. 00271 */ 00272 //@{ 00273 /** 00274 * @brief Simple extraction. 00275 * @return A character, or eof(). 00276 * 00277 * Tries to extract a character. If none are available, sets failbit 00278 * and returns traits::eof(). 00279 */ 00280 int_type 00281 get(); 00282 00283 /** 00284 * @brief Simple extraction. 00285 * @param c The character in which to store data. 00286 * @return *this 00287 * 00288 * Tries to extract a character and store it in @a c. If none are 00289 * available, sets failbit and returns traits::eof(). 00290 * 00291 * @note This function is not overloaded on signed char and 00292 * unsigned char. 00293 */ 00294 __istream_type& 00295 get(char_type& __c); 00296 00297 /** 00298 * @brief Simple multiple-character extraction. 00299 * @param s Pointer to an array. 00300 * @param n Maximum number of characters to store in @a s. 00301 * @param delim A "stop" character. 00302 * @return *this 00303 * 00304 * Characters are extracted and stored into @a s until one of the 00305 * following happens: 00306 * 00307 * - @c n-1 characters are stored 00308 * - the input sequence reaches EOF 00309 * - the next character equals @a delim, in which case the character 00310 * is not extracted 00311 * 00312 * If no characters are stored, failbit is set in the stream's error 00313 * state. 00314 * 00315 * In any case, a null character is stored into the next location in 00316 * the array. 00317 * 00318 * @note This function is not overloaded on signed char and 00319 * unsigned char. 00320 */ 00321 __istream_type& 00322 get(char_type* __s, streamsize __n, char_type __delim); 00323 00324 /** 00325 * @brief Simple multiple-character extraction. 00326 * @param s Pointer to an array. 00327 * @param n Maximum number of characters to store in @a s. 00328 * @return *this 00329 * 00330 * Returns @c get(s,n,widen('\\n')). 00331 */ 00332 __istream_type& 00333 get(char_type* __s, streamsize __n) 00334 { return this->get(__s, __n, this->widen('\n')); } 00335 00336 /** 00337 * @brief Extraction into another streambuf. 00338 * @param sb A streambuf in which to store data. 00339 * @param delim A "stop" character. 00340 * @return *this 00341 * 00342 * Characters are extracted and inserted into @a sb until one of the 00343 * following happens: 00344 * 00345 * - the input sequence reaches EOF 00346 * - insertion into the output buffer fails (in this case, the 00347 * character that would have been inserted is not extracted) 00348 * - the next character equals @a delim (in this case, the character 00349 * is not extracted) 00350 * - an exception occurs (and in this case is caught) 00351 * 00352 * If no characters are stored, failbit is set in the stream's error 00353 * state. 00354 */ 00355 __istream_type& 00356 get(__streambuf_type& __sb, char_type __delim); 00357 00358 /** 00359 * @brief Extraction into another streambuf. 00360 * @param sb A streambuf in which to store data. 00361 * @return *this 00362 * 00363 * Returns @c get(sb,widen('\\n')). 00364 */ 00365 __istream_type& 00366 get(__streambuf_type& __sb) 00367 { return this->get(__sb, this->widen('\n')); } 00368 00369 /** 00370 * @brief String extraction. 00371 * @param s A character array in which to store the data. 00372 * @param n Maximum number of characters to extract. 00373 * @param delim A "stop" character. 00374 * @return *this 00375 * 00376 * Extracts and stores characters into @a s until one of the 00377 * following happens. Note that these criteria are required to be 00378 * tested in the order listed here, to allow an input line to exactly 00379 * fill the @a s array without setting failbit. 00380 * 00381 * -# the input sequence reaches end-of-file, in which case eofbit 00382 * is set in the stream error state 00383 * -# the next character equals @c delim, in which case the character 00384 * is extracted (and therefore counted in @c gcount()) but not stored 00385 * -# @c n-1 characters are stored, in which case failbit is set 00386 * in the stream error state 00387 * 00388 * If no characters are extracted, failbit is set. (An empty line of 00389 * input should therefore not cause failbit to be set.) 00390 * 00391 * In any case, a null character is stored in the next location in 00392 * the array. 00393 */ 00394 __istream_type& 00395 getline(char_type* __s, streamsize __n, char_type __delim); 00396 00397 /** 00398 * @brief String extraction. 00399 * @param s A character array in which to store the data. 00400 * @param n Maximum number of characters to extract. 00401 * @return *this 00402 * 00403 * Returns @c getline(s,n,widen('\\n')). 00404 */ 00405 __istream_type& 00406 getline(char_type* __s, streamsize __n) 00407 { return this->getline(__s, __n, this->widen('\n')); } 00408 00409 /** 00410 * @brief Discarding characters 00411 * @param n Number of characters to discard. 00412 * @param delim A "stop" character. 00413 * @return *this 00414 * 00415 * Extracts characters and throws them away until one of the 00416 * following happens: 00417 * - if @a n @c != @c std::numeric_limits<int>::max(), @a n 00418 * characters are extracted 00419 * - the input sequence reaches end-of-file 00420 * - the next character equals @a delim (in this case, the character 00421 * is extracted); note that this condition will never occur if 00422 * @a delim equals @c traits::eof(). 00423 * 00424 * NB: Provide three overloads, instead of the single function 00425 * (with defaults) mandated by the Standard: this leads to a 00426 * better performing implementation, while still conforming to 00427 * the Standard. 00428 */ 00429 __istream_type& 00430 ignore(); 00431 00432 __istream_type& 00433 ignore(streamsize __n); 00434 00435 __istream_type& 00436 ignore(streamsize __n, int_type __delim); 00437 00438 /** 00439 * @brief Looking ahead in the stream 00440 * @return The next character, or eof(). 00441 * 00442 * If, after constructing the sentry object, @c good() is false, 00443 * returns @c traits::eof(). Otherwise reads but does not extract 00444 * the next input character. 00445 */ 00446 int_type 00447 peek(); 00448 00449 /** 00450 * @brief Extraction without delimiters. 00451 * @param s A character array. 00452 * @param n Maximum number of characters to store. 00453 * @return *this 00454 * 00455 * If the stream state is @c good(), extracts characters and stores 00456 * them into @a s until one of the following happens: 00457 * - @a n characters are stored 00458 * - the input sequence reaches end-of-file, in which case the error 00459 * state is set to @c failbit|eofbit. 00460 * 00461 * @note This function is not overloaded on signed char and 00462 * unsigned char. 00463 */ 00464 __istream_type& 00465 read(char_type* __s, streamsize __n); 00466 00467 /** 00468 * @brief Extraction until the buffer is exhausted, but no more. 00469 * @param s A character array. 00470 * @param n Maximum number of characters to store. 00471 * @return The number of characters extracted. 00472 * 00473 * Extracts characters and stores them into @a s depending on the 00474 * number of characters remaining in the streambuf's buffer, 00475 * @c rdbuf()->in_avail(), called @c A here: 00476 * - if @c A @c == @c -1, sets eofbit and extracts no characters 00477 * - if @c A @c == @c 0, extracts no characters 00478 * - if @c A @c > @c 0, extracts @c min(A,n) 00479 * 00480 * The goal is to empty the current buffer, and to not request any 00481 * more from the external input sequence controlled by the streambuf. 00482 */ 00483 streamsize 00484 readsome(char_type* __s, streamsize __n); 00485 00486 /** 00487 * @brief Unextracting a single character. 00488 * @param c The character to push back into the input stream. 00489 * @return *this 00490 * 00491 * If @c rdbuf() is not null, calls @c rdbuf()->sputbackc(c). 00492 * 00493 * If @c rdbuf() is null or if @c sputbackc() fails, sets badbit in 00494 * the error state. 00495 * 00496 * @note Since no characters are extracted, the next call to 00497 * @c gcount() will return 0, as required by DR 60. 00498 */ 00499 __istream_type& 00500 putback(char_type __c); 00501 00502 /** 00503 * @brief Unextracting the previous character. 00504 * @return *this 00505 * 00506 * If @c rdbuf() is not null, calls @c rdbuf()->sungetc(c). 00507 * 00508 * If @c rdbuf() is null or if @c sungetc() fails, sets badbit in 00509 * the error state. 00510 * 00511 * @note Since no characters are extracted, the next call to 00512 * @c gcount() will return 0, as required by DR 60. 00513 */ 00514 __istream_type& 00515 unget(); 00516 00517 /** 00518 * @brief Synchronizing the stream buffer. 00519 * @return 0 on success, -1 on failure 00520 * 00521 * If @c rdbuf() is a null pointer, returns -1. 00522 * 00523 * Otherwise, calls @c rdbuf()->pubsync(), and if that returns -1, 00524 * sets badbit and returns -1. 00525 * 00526 * Otherwise, returns 0. 00527 * 00528 * @note This function does not count the number of characters 00529 * extracted, if any, and therefore does not affect the next 00530 * call to @c gcount(). 00531 */ 00532 int 00533 sync(); 00534 00535 /** 00536 * @brief Getting the current read position. 00537 * @return A file position object. 00538 * 00539 * If @c fail() is not false, returns @c pos_type(-1) to indicate 00540 * failure. Otherwise returns @c rdbuf()->pubseekoff(0,cur,in). 00541 * 00542 * @note This function does not count the number of characters 00543 * extracted, if any, and therefore does not affect the next 00544 * call to @c gcount(). 00545 */ 00546 pos_type 00547 tellg(); 00548 00549 /** 00550 * @brief Changing the current read position. 00551 * @param pos A file position object. 00552 * @return *this 00553 * 00554 * If @c fail() is not true, calls @c rdbuf()->pubseekpos(pos). If 00555 * that function fails, sets failbit. 00556 * 00557 * @note This function does not count the number of characters 00558 * extracted, if any, and therefore does not affect the next 00559 * call to @c gcount(). 00560 */ 00561 __istream_type& 00562 seekg(pos_type); 00563 00564 /** 00565 * @brief Changing the current read position. 00566 * @param off A file offset object. 00567 * @param dir The direction in which to seek. 00568 * @return *this 00569 * 00570 * If @c fail() is not true, calls @c rdbuf()->pubseekoff(off,dir). 00571 * If that function fails, sets failbit. 00572 * 00573 * @note This function does not count the number of characters 00574 * extracted, if any, and therefore does not affect the next 00575 * call to @c gcount(). 00576 */ 00577 __istream_type& 00578 seekg(off_type, ios_base::seekdir); 00579 //@} 00580 00581 protected: 00582 basic_istream() 00583 : _M_gcount(streamsize(0)) 00584 { this->init(0); } 00585 00586 template<typename _ValueT> 00587 __istream_type& 00588 _M_extract(_ValueT& __v); 00589 }; 00590 00591 // Explicit specialization declarations, defined in src/istream.cc. 00592 template<> 00593 basic_istream<char>& 00594 basic_istream<char>:: 00595 getline(char_type* __s, streamsize __n, char_type __delim); 00596 00597 template<> 00598 basic_istream<char>& 00599 basic_istream<char>:: 00600 ignore(streamsize __n); 00601 00602 template<> 00603 basic_istream<char>& 00604 basic_istream<char>:: 00605 ignore(streamsize __n, int_type __delim); 00606 00607 #ifdef _GLIBCXX_USE_WCHAR_T 00608 template<> 00609 basic_istream<wchar_t>& 00610 basic_istream<wchar_t>:: 00611 getline(char_type* __s, streamsize __n, char_type __delim); 00612 00613 template<> 00614 basic_istream<wchar_t>& 00615 basic_istream<wchar_t>:: 00616 ignore(streamsize __n); 00617 00618 template<> 00619 basic_istream<wchar_t>& 00620 basic_istream<wchar_t>:: 00621 ignore(streamsize __n, int_type __delim); 00622 #endif 00623 00624 /** 00625 * @brief Performs setup work for input streams. 00626 * 00627 * Objects of this class are created before all of the standard 00628 * extractors are run. It is responsible for <em>exception-safe 00629 * prefix and suffix operations,</em> although only prefix actions 00630 * are currently required by the standard. 00631 */ 00632 template<typename _CharT, typename _Traits> 00633 class basic_istream<_CharT, _Traits>::sentry 00634 { 00635 // Data Members. 00636 bool _M_ok; 00637 00638 public: 00639 /// Easy access to dependant types. 00640 typedef _Traits traits_type; 00641 typedef basic_streambuf<_CharT, _Traits> __streambuf_type; 00642 typedef basic_istream<_CharT, _Traits> __istream_type; 00643 typedef typename __istream_type::__ctype_type __ctype_type; 00644 typedef typename _Traits::int_type __int_type; 00645 00646 /** 00647 * @brief The constructor performs all the work. 00648 * @param is The input stream to guard. 00649 * @param noskipws Whether to consume whitespace or not. 00650 * 00651 * If the stream state is good (@a is.good() is true), then the 00652 * following actions are performed, otherwise the sentry state 00653 * is false (<em>not okay</em>) and failbit is set in the 00654 * stream state. 00655 * 00656 * The sentry's preparatory actions are: 00657 * 00658 * -# if the stream is tied to an output stream, @c is.tie()->flush() 00659 * is called to synchronize the output sequence 00660 * -# if @a noskipws is false, and @c ios_base::skipws is set in 00661 * @c is.flags(), the sentry extracts and discards whitespace 00662 * characters from the stream. The currently imbued locale is 00663 * used to determine whether each character is whitespace. 00664 * 00665 * If the stream state is still good, then the sentry state becomes 00666 * true (@a okay). 00667 */ 00668 explicit 00669 sentry(basic_istream<_CharT, _Traits>& __is, bool __noskipws = false); 00670 00671 /** 00672 * @brief Quick status checking. 00673 * @return The sentry state. 00674 * 00675 * For ease of use, sentries may be converted to booleans. The 00676 * return value is that of the sentry state (true == okay). 00677 */ 00678 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 00679 explicit 00680 #endif 00681 operator bool() const 00682 { return _M_ok; } 00683 }; 00684 00685 // [27.6.1.2.3] character extraction templates 00686 //@{ 00687 /** 00688 * @brief Character extractors 00689 * @param in An input stream. 00690 * @param c A character reference. 00691 * @return in 00692 * 00693 * Behaves like one of the formatted arithmetic extractors described in 00694 * std::basic_istream. After constructing a sentry object with good 00695 * status, this function extracts a character (if one is available) and 00696 * stores it in @a c. Otherwise, sets failbit in the input stream. 00697 */ 00698 template<typename _CharT, typename _Traits> 00699 basic_istream<_CharT, _Traits>& 00700 operator>>(basic_istream<_CharT, _Traits>& __in, _CharT& __c); 00701 00702 template<class _Traits> 00703 inline basic_istream<char, _Traits>& 00704 operator>>(basic_istream<char, _Traits>& __in, unsigned char& __c) 00705 { return (__in >> reinterpret_cast<char&>(__c)); } 00706 00707 template<class _Traits> 00708 inline basic_istream<char, _Traits>& 00709 operator>>(basic_istream<char, _Traits>& __in, signed char& __c) 00710 { return (__in >> reinterpret_cast<char&>(__c)); } 00711 //@} 00712 00713 //@{ 00714 /** 00715 * @brief Character string extractors 00716 * @param in An input stream. 00717 * @param s A pointer to a character array. 00718 * @return in 00719 * 00720 * Behaves like one of the formatted arithmetic extractors described in 00721 * std::basic_istream. After constructing a sentry object with good 00722 * status, this function extracts up to @c n characters and stores them 00723 * into the array starting at @a s. @c n is defined as: 00724 * 00725 * - if @c width() is greater than zero, @c n is width() otherwise 00726 * - @c n is <em>the number of elements of the largest array of * 00727 * - @c char_type that can store a terminating @c eos.</em> 00728 * - [27.6.1.2.3]/6 00729 * 00730 * Characters are extracted and stored until one of the following happens: 00731 * - @c n-1 characters are stored 00732 * - EOF is reached 00733 * - the next character is whitespace according to the current locale 00734 * - the next character is a null byte (i.e., @c charT() ) 00735 * 00736 * @c width(0) is then called for the input stream. 00737 * 00738 * If no characters are extracted, sets failbit. 00739 */ 00740 template<typename _CharT, typename _Traits> 00741 basic_istream<_CharT, _Traits>& 00742 operator>>(basic_istream<_CharT, _Traits>& __in, _CharT* __s); 00743 00744 // Explicit specialization declaration, defined in src/istream.cc. 00745 template<> 00746 basic_istream<char>& 00747 operator>>(basic_istream<char>& __in, char* __s); 00748 00749 template<class _Traits> 00750 inline basic_istream<char, _Traits>& 00751 operator>>(basic_istream<char, _Traits>& __in, unsigned char* __s) 00752 { return (__in >> reinterpret_cast<char*>(__s)); } 00753 00754 template<class _Traits> 00755 inline basic_istream<char, _Traits>& 00756 operator>>(basic_istream<char, _Traits>& __in, signed char* __s) 00757 { return (__in >> reinterpret_cast<char*>(__s)); } 00758 //@} 00759 00760 // 27.6.1.5 Template class basic_iostream 00761 /** 00762 * @brief Merging istream and ostream capabilities. 00763 * @ingroup io 00764 * 00765 * This class multiply inherits from the input and output stream classes 00766 * simply to provide a single interface. 00767 */ 00768 template<typename _CharT, typename _Traits> 00769 class basic_iostream 00770 : public basic_istream<_CharT, _Traits>, 00771 public basic_ostream<_CharT, _Traits> 00772 { 00773 public: 00774 // _GLIBCXX_RESOLVE_LIB_DEFECTS 00775 // 271. basic_iostream missing typedefs 00776 // Types (inherited): 00777 typedef _CharT char_type; 00778 typedef typename _Traits::int_type int_type; 00779 typedef typename _Traits::pos_type pos_type; 00780 typedef typename _Traits::off_type off_type; 00781 typedef _Traits traits_type; 00782 00783 // Non-standard Types: 00784 typedef basic_istream<_CharT, _Traits> __istream_type; 00785 typedef basic_ostream<_CharT, _Traits> __ostream_type; 00786 00787 /** 00788 * @brief Constructor does nothing. 00789 * 00790 * Both of the parent classes are initialized with the same 00791 * streambuf pointer passed to this constructor. 00792 */ 00793 explicit 00794 basic_iostream(basic_streambuf<_CharT, _Traits>* __sb) 00795 : __istream_type(__sb), __ostream_type(__sb) { } 00796 00797 /** 00798 * @brief Destructor does nothing. 00799 */ 00800 virtual 00801 ~basic_iostream() { } 00802 00803 protected: 00804 basic_iostream() 00805 : __istream_type(), __ostream_type() { } 00806 }; 00807 00808 // [27.6.1.4] standard basic_istream manipulators 00809 /** 00810 * @brief Quick and easy way to eat whitespace 00811 * 00812 * This manipulator extracts whitespace characters, stopping when the 00813 * next character is non-whitespace, or when the input sequence is empty. 00814 * If the sequence is empty, @c eofbit is set in the stream, but not 00815 * @c failbit. 00816 * 00817 * The current locale is used to distinguish whitespace characters. 00818 * 00819 * Example: 00820 * @code 00821 * MyClass mc; 00822 * 00823 * std::cin >> std::ws >> mc; 00824 * @endcode 00825 * will skip leading whitespace before calling operator>> on cin and your 00826 * object. Note that the same effect can be achieved by creating a 00827 * std::basic_istream::sentry inside your definition of operator>>. 00828 */ 00829 template<typename _CharT, typename _Traits> 00830 basic_istream<_CharT, _Traits>& 00831 ws(basic_istream<_CharT, _Traits>& __is); 00832 00833 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 00834 // [27.7.1.6] Rvalue stream extraction 00835 /** 00836 * @brief Generic extractor for rvalue stream 00837 * @param is An input stream. 00838 * @param x A reference to the extraction target. 00839 * @return is 00840 * 00841 * This is just a forwarding function to allow extraction from 00842 * rvalue streams since they won't bind to the extractor functions 00843 * that take an lvalue reference. 00844 */ 00845 template<typename _CharT, typename _Traits, typename _Tp> 00846 inline basic_istream<_CharT, _Traits>& 00847 operator>>(basic_istream<_CharT, _Traits>&& __is, _Tp& __x) 00848 { return (__is >> __x); } 00849 #endif // __GXX_EXPERIMENTAL_CXX0X__ 00850 00851 _GLIBCXX_END_NAMESPACE 00852 00853 #ifndef _GLIBCXX_EXPORT_TEMPLATE 00854 # include <bits/istream.tcc> 00855 #endif 00856 00857 #endif /* _GLIBCXX_ISTREAM */