00001 // Input streams -*- C++ -*- 00002 00003 // Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 00004 // 2006, 2007, 2008 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 2, 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 // You should have received a copy of the GNU General Public License 00019 // along with this library; see the file COPYING. If not, write to 00020 // the Free Software Foundation, 51 Franklin Street, Fifth Floor, 00021 // Boston, MA 02110-1301, USA. 00022 00023 // As a special exception, you may use this file as part of a free software 00024 // library without restriction. Specifically, if other files instantiate 00025 // templates or use macros or inline functions from this file, or you compile 00026 // this file and link it with other files to produce an executable, this 00027 // file does not by itself cause the resulting executable to be covered by 00028 // the GNU General Public License. This exception does not however 00029 // invalidate any other reasons why the executable file might be covered by 00030 // the GNU General Public License. 00031 00032 // 00033 // ISO C++ 14882: 27.6.1 Input streams 00034 // 00035 00036 /** @file istream 00037 * This is a Standard C++ Library header. 00038 */ 00039 00040 #ifndef _GLIBCXX_ISTREAM 00041 #define _GLIBCXX_ISTREAM 1 00042 00043 #pragma GCC system_header 00044 00045 #include <ios> 00046 #include <ostream> 00047 00048 _GLIBCXX_BEGIN_NAMESPACE(std) 00049 00050 // [27.6.1.1] Template class basic_istream 00051 /** 00052 * @brief Controlling input. 00053 * 00054 * This is the base class for all input streams. It provides text 00055 * formatting of all builtin types, and communicates with any class 00056 * derived from basic_streambuf to do the actual input. 00057 */ 00058 template<typename _CharT, typename _Traits> 00059 class basic_istream : virtual public basic_ios<_CharT, _Traits> 00060 { 00061 public: 00062 // Types (inherited from basic_ios (27.4.4)): 00063 typedef _CharT char_type; 00064 typedef typename _Traits::int_type int_type; 00065 typedef typename _Traits::pos_type pos_type; 00066 typedef typename _Traits::off_type off_type; 00067 typedef _Traits traits_type; 00068 00069 // Non-standard Types: 00070 typedef basic_streambuf<_CharT, _Traits> __streambuf_type; 00071 typedef basic_ios<_CharT, _Traits> __ios_type; 00072 typedef basic_istream<_CharT, _Traits> __istream_type; 00073 typedef num_get<_CharT, istreambuf_iterator<_CharT, _Traits> > 00074 __num_get_type; 00075 typedef ctype<_CharT> __ctype_type; 00076 00077 protected: 00078 // Data Members: 00079 /** 00080 * The number of characters extracted in the previous unformatted 00081 * function; see gcount(). 00082 */ 00083 streamsize _M_gcount; 00084 00085 public: 00086 // [27.6.1.1.1] constructor/destructor 00087 /** 00088 * @brief Base constructor. 00089 * 00090 * This ctor is almost never called by the user directly, rather from 00091 * derived classes' initialization lists, which pass a pointer to 00092 * their own stream buffer. 00093 */ 00094 explicit 00095 basic_istream(__streambuf_type* __sb) 00096 : _M_gcount(streamsize(0)) 00097 { this->init(__sb); } 00098 00099 /** 00100 * @brief Base destructor. 00101 * 00102 * This does very little apart from providing a virtual base dtor. 00103 */ 00104 virtual 00105 ~basic_istream() 00106 { _M_gcount = streamsize(0); } 00107 00108 // [27.6.1.1.2] prefix/suffix 00109 class sentry; 00110 friend class sentry; 00111 00112 // [27.6.1.2] formatted input 00113 // [27.6.1.2.3] basic_istream::operator>> 00114 //@{ 00115 /** 00116 * @brief Interface for manipulators. 00117 * 00118 * Manipulators such as @c std::ws and @c std::dec use these 00119 * functions in constructs like "std::cin >> std::ws". For more 00120 * information, see the iomanip header. 00121 */ 00122 __istream_type& 00123 operator>>(__istream_type& (*__pf)(__istream_type&)) 00124 { return __pf(*this); } 00125 00126 __istream_type& 00127 operator>>(__ios_type& (*__pf)(__ios_type&)) 00128 { 00129 __pf(*this); 00130 return *this; 00131 } 00132 00133 __istream_type& 00134 operator>>(ios_base& (*__pf)(ios_base&)) 00135 { 00136 __pf(*this); 00137 return *this; 00138 } 00139 //@} 00140 00141 // [27.6.1.2.2] arithmetic extractors 00142 /** 00143 * @name Arithmetic Extractors 00144 * 00145 * All the @c operator>> functions (aka <em>formatted input 00146 * functions</em>) have some common behavior. Each starts by 00147 * constructing a temporary object of type std::basic_istream::sentry 00148 * with the second argument (noskipws) set to false. This has several 00149 * effects, concluding with the setting of a status flag; see the 00150 * sentry documentation for more. 00151 * 00152 * If the sentry status is good, the function tries to extract 00153 * whatever data is appropriate for the type of the argument. 00154 * 00155 * If an exception is thrown during extraction, ios_base::badbit 00156 * will be turned on in the stream's error state without causing an 00157 * ios_base::failure to be thrown. The original exception will then 00158 * be rethrown. 00159 */ 00160 //@{ 00161 /** 00162 * @brief Basic arithmetic extractors 00163 * @param A variable of builtin type. 00164 * @return @c *this if successful 00165 * 00166 * These functions use the stream's current locale (specifically, the 00167 * @c num_get facet) to parse the input data. 00168 */ 00169 __istream_type& 00170 operator>>(bool& __n) 00171 { return _M_extract(__n); } 00172 00173 __istream_type& 00174 operator>>(short& __n); 00175 00176 __istream_type& 00177 operator>>(unsigned short& __n) 00178 { return _M_extract(__n); } 00179 00180 __istream_type& 00181 operator>>(int& __n); 00182 00183 __istream_type& 00184 operator>>(unsigned int& __n) 00185 { return _M_extract(__n); } 00186 00187 __istream_type& 00188 operator>>(long& __n) 00189 { return _M_extract(__n); } 00190 00191 __istream_type& 00192 operator>>(unsigned long& __n) 00193 { return _M_extract(__n); } 00194 00195 #ifdef _GLIBCXX_USE_LONG_LONG 00196 __istream_type& 00197 operator>>(long long& __n) 00198 { return _M_extract(__n); } 00199 00200 __istream_type& 00201 operator>>(unsigned long long& __n) 00202 { return _M_extract(__n); } 00203 #endif 00204 00205 __istream_type& 00206 operator>>(float& __f) 00207 { return _M_extract(__f); } 00208 00209 __istream_type& 00210 operator>>(double& __f) 00211 { return _M_extract(__f); } 00212 00213 __istream_type& 00214 operator>>(long double& __f) 00215 { return _M_extract(__f); } 00216 00217 __istream_type& 00218 operator>>(void*& __p) 00219 { return _M_extract(__p); } 00220 00221 /** 00222 * @brief Extracting into another streambuf. 00223 * @param sb A pointer to a streambuf 00224 * 00225 * This function behaves like one of the basic arithmetic extractors, 00226 * in that it also constructs a sentry object and has the same error 00227 * handling behavior. 00228 * 00229 * If @a sb is NULL, the stream will set failbit in its error state. 00230 * 00231 * Characters are extracted from this stream and inserted into the 00232 * @a sb streambuf until one of the following occurs: 00233 * 00234 * - the input stream reaches end-of-file, 00235 * - insertion into the output buffer fails (in this case, the 00236 * character that would have been inserted is not extracted), or 00237 * - an exception occurs (and in this case is caught) 00238 * 00239 * If the function inserts no characters, failbit is set. 00240 */ 00241 __istream_type& 00242 operator>>(__streambuf_type* __sb); 00243 //@} 00244 00245 // [27.6.1.3] unformatted input 00246 /** 00247 * @brief Character counting 00248 * @return The number of characters extracted by the previous 00249 * unformatted input function dispatched for this stream. 00250 */ 00251 streamsize 00252 gcount() const 00253 { return _M_gcount; } 00254 00255 /** 00256 * @name Unformatted Input Functions 00257 * 00258 * All the unformatted input functions have some common behavior. 00259 * Each starts by constructing a temporary object of type 00260 * std::basic_istream::sentry with the second argument (noskipws) 00261 * set to true. This has several effects, concluding with the 00262 * setting of a status flag; see the sentry documentation for more. 00263 * 00264 * If the sentry status is good, the function tries to extract 00265 * whatever data is appropriate for the type of the argument. 00266 * 00267 * The number of characters extracted is stored for later retrieval 00268 * by gcount(). 00269 * 00270 * If an exception is thrown during extraction, ios_base::badbit 00271 * will be turned on in the stream's error state without causing an 00272 * ios_base::failure to be thrown. The original exception will then 00273 * be rethrown. 00274 */ 00275 //@{ 00276 /** 00277 * @brief Simple extraction. 00278 * @return A character, or eof(). 00279 * 00280 * Tries to extract a character. If none are available, sets failbit 00281 * and returns traits::eof(). 00282 */ 00283 int_type 00284 get(); 00285 00286 /** 00287 * @brief Simple extraction. 00288 * @param c The character in which to store data. 00289 * @return *this 00290 * 00291 * Tries to extract a character and store it in @a c. If none are 00292 * available, sets failbit and returns traits::eof(). 00293 * 00294 * @note This function is not overloaded on signed char and 00295 * unsigned char. 00296 */ 00297 __istream_type& 00298 get(char_type& __c); 00299 00300 /** 00301 * @brief Simple multiple-character extraction. 00302 * @param s Pointer to an array. 00303 * @param n Maximum number of characters to store in @a s. 00304 * @param delim A "stop" character. 00305 * @return *this 00306 * 00307 * Characters are extracted and stored into @a s until one of the 00308 * following happens: 00309 * 00310 * - @c n-1 characters are stored 00311 * - the input sequence reaches EOF 00312 * - the next character equals @a delim, in which case the character 00313 * is not extracted 00314 * 00315 * If no characters are stored, failbit is set in the stream's error 00316 * state. 00317 * 00318 * In any case, a null character is stored into the next location in 00319 * the array. 00320 * 00321 * @note This function is not overloaded on signed char and 00322 * unsigned char. 00323 */ 00324 __istream_type& 00325 get(char_type* __s, streamsize __n, char_type __delim); 00326 00327 /** 00328 * @brief Simple multiple-character extraction. 00329 * @param s Pointer to an array. 00330 * @param n Maximum number of characters to store in @a s. 00331 * @return *this 00332 * 00333 * Returns @c get(s,n,widen('\n')). 00334 */ 00335 __istream_type& 00336 get(char_type* __s, streamsize __n) 00337 { return this->get(__s, __n, this->widen('\n')); } 00338 00339 /** 00340 * @brief Extraction into another streambuf. 00341 * @param sb A streambuf in which to store data. 00342 * @param delim A "stop" character. 00343 * @return *this 00344 * 00345 * Characters are extracted and inserted into @a sb until one of the 00346 * following happens: 00347 * 00348 * - the input sequence reaches EOF 00349 * - insertion into the output buffer fails (in this case, the 00350 * character that would have been inserted is not extracted) 00351 * - the next character equals @a delim (in this case, the character 00352 * is not extracted) 00353 * - an exception occurs (and in this case is caught) 00354 * 00355 * If no characters are stored, failbit is set in the stream's error 00356 * state. 00357 */ 00358 __istream_type& 00359 get(__streambuf_type& __sb, char_type __delim); 00360 00361 /** 00362 * @brief Extraction into another streambuf. 00363 * @param sb A streambuf in which to store data. 00364 * @return *this 00365 * 00366 * Returns @c get(sb,widen('\n')). 00367 */ 00368 __istream_type& 00369 get(__streambuf_type& __sb) 00370 { return this->get(__sb, this->widen('\n')); } 00371 00372 /** 00373 * @brief String extraction. 00374 * @param s A character array in which to store the data. 00375 * @param n Maximum number of characters to extract. 00376 * @param delim A "stop" character. 00377 * @return *this 00378 * 00379 * Extracts and stores characters into @a s until one of the 00380 * following happens. Note that these criteria are required to be 00381 * tested in the order listed here, to allow an input line to exactly 00382 * fill the @a s array without setting failbit. 00383 * 00384 * -# the input sequence reaches end-of-file, in which case eofbit 00385 * is set in the stream error state 00386 * -# the next character equals @c delim, in which case the character 00387 * is extracted (and therefore counted in @c gcount()) but not stored 00388 * -# @c n-1 characters are stored, in which case failbit is set 00389 * in the stream error state 00390 * 00391 * If no characters are extracted, failbit is set. (An empty line of 00392 * input should therefore not cause failbit to be set.) 00393 * 00394 * In any case, a null character is stored in the next location in 00395 * the array. 00396 */ 00397 __istream_type& 00398 getline(char_type* __s, streamsize __n, char_type __delim); 00399 00400 /** 00401 * @brief String extraction. 00402 * @param s A character array in which to store the data. 00403 * @param n Maximum number of characters to extract. 00404 * @return *this 00405 * 00406 * Returns @c getline(s,n,widen('\n')). 00407 */ 00408 __istream_type& 00409 getline(char_type* __s, streamsize __n) 00410 { return this->getline(__s, __n, this->widen('\n')); } 00411 00412 /** 00413 * @brief Discarding characters 00414 * @param n Number of characters to discard. 00415 * @param delim A "stop" character. 00416 * @return *this 00417 * 00418 * Extracts characters and throws them away until one of the 00419 * following happens: 00420 * - if @a n @c != @c std::numeric_limits<int>::max(), @a n 00421 * characters are extracted 00422 * - the input sequence reaches end-of-file 00423 * - the next character equals @a delim (in this case, the character 00424 * is extracted); note that this condition will never occur if 00425 * @a delim equals @c traits::eof(). 00426 * 00427 * NB: Provide three overloads, instead of the single function 00428 * (with defaults) mandated by the Standard: this leads to a 00429 * better performing implementation, while still conforming to 00430 * the Standard. 00431 */ 00432 __istream_type& 00433 ignore(); 00434 00435 __istream_type& 00436 ignore(streamsize __n); 00437 00438 __istream_type& 00439 ignore(streamsize __n, int_type __delim); 00440 00441 /** 00442 * @brief Looking ahead in the stream 00443 * @return The next character, or eof(). 00444 * 00445 * If, after constructing the sentry object, @c good() is false, 00446 * returns @c traits::eof(). Otherwise reads but does not extract 00447 * the next input character. 00448 */ 00449 int_type 00450 peek(); 00451 00452 /** 00453 * @brief Extraction without delimiters. 00454 * @param s A character array. 00455 * @param n Maximum number of characters to store. 00456 * @return *this 00457 * 00458 * If the stream state is @c good(), extracts characters and stores 00459 * them into @a s until one of the following happens: 00460 * - @a n characters are stored 00461 * - the input sequence reaches end-of-file, in which case the error 00462 * state is set to @c failbit|eofbit. 00463 * 00464 * @note This function is not overloaded on signed char and 00465 * unsigned char. 00466 */ 00467 __istream_type& 00468 read(char_type* __s, streamsize __n); 00469 00470 /** 00471 * @brief Extraction until the buffer is exhausted, but no more. 00472 * @param s A character array. 00473 * @param n Maximum number of characters to store. 00474 * @return The number of characters extracted. 00475 * 00476 * Extracts characters and stores them into @a s depending on the 00477 * number of characters remaining in the streambuf's buffer, 00478 * @c rdbuf()->in_avail(), called @c A here: 00479 * - if @c A @c == @c -1, sets eofbit and extracts no characters 00480 * - if @c A @c == @c 0, extracts no characters 00481 * - if @c A @c > @c 0, extracts @c min(A,n) 00482 * 00483 * The goal is to empty the current buffer, and to not request any 00484 * more from the external input sequence controlled by the streambuf. 00485 */ 00486 streamsize 00487 readsome(char_type* __s, streamsize __n); 00488 00489 /** 00490 * @brief Unextracting a single character. 00491 * @param c The character to push back into the input stream. 00492 * @return *this 00493 * 00494 * If @c rdbuf() is not null, calls @c rdbuf()->sputbackc(c). 00495 * 00496 * If @c rdbuf() is null or if @c sputbackc() fails, sets badbit in 00497 * the error state. 00498 * 00499 * @note Since no characters are extracted, the next call to 00500 * @c gcount() will return 0, as required by DR 60. 00501 */ 00502 __istream_type& 00503 putback(char_type __c); 00504 00505 /** 00506 * @brief Unextracting the previous character. 00507 * @return *this 00508 * 00509 * If @c rdbuf() is not null, calls @c rdbuf()->sungetc(c). 00510 * 00511 * If @c rdbuf() is null or if @c sungetc() fails, sets badbit in 00512 * the error state. 00513 * 00514 * @note Since no characters are extracted, the next call to 00515 * @c gcount() will return 0, as required by DR 60. 00516 */ 00517 __istream_type& 00518 unget(); 00519 00520 /** 00521 * @brief Synchronizing the stream buffer. 00522 * @return 0 on success, -1 on failure 00523 * 00524 * If @c rdbuf() is a null pointer, returns -1. 00525 * 00526 * Otherwise, calls @c rdbuf()->pubsync(), and if that returns -1, 00527 * sets badbit and returns -1. 00528 * 00529 * Otherwise, returns 0. 00530 * 00531 * @note This function does not count the number of characters 00532 * extracted, if any, and therefore does not affect the next 00533 * call to @c gcount(). 00534 */ 00535 int 00536 sync(); 00537 00538 /** 00539 * @brief Getting the current read position. 00540 * @return A file position object. 00541 * 00542 * If @c fail() is not false, returns @c pos_type(-1) to indicate 00543 * failure. Otherwise returns @c rdbuf()->pubseekoff(0,cur,in). 00544 * 00545 * @note This function does not count the number of characters 00546 * extracted, if any, and therefore does not affect the next 00547 * call to @c gcount(). 00548 */ 00549 pos_type 00550 tellg(); 00551 00552 /** 00553 * @brief Changing the current read position. 00554 * @param pos A file position object. 00555 * @return *this 00556 * 00557 * If @c fail() is not true, calls @c rdbuf()->pubseekpos(pos). If 00558 * that function fails, sets failbit. 00559 * 00560 * @note This function does not count the number of characters 00561 * extracted, if any, and therefore does not affect the next 00562 * call to @c gcount(). 00563 */ 00564 __istream_type& 00565 seekg(pos_type); 00566 00567 /** 00568 * @brief Changing the current read position. 00569 * @param off A file offset object. 00570 * @param dir The direction in which to seek. 00571 * @return *this 00572 * 00573 * If @c fail() is not true, calls @c rdbuf()->pubseekoff(off,dir). 00574 * If that function fails, sets failbit. 00575 * 00576 * @note This function does not count the number of characters 00577 * extracted, if any, and therefore does not affect the next 00578 * call to @c gcount(). 00579 */ 00580 __istream_type& 00581 seekg(off_type, ios_base::seekdir); 00582 //@} 00583 00584 protected: 00585 basic_istream() 00586 : _M_gcount(streamsize(0)) 00587 { this->init(0); } 00588 00589 template<typename _ValueT> 00590 __istream_type& 00591 _M_extract(_ValueT& __v); 00592 }; 00593 00594 // Explicit specialization declarations, defined in src/istream.cc. 00595 template<> 00596 basic_istream<char>& 00597 basic_istream<char>:: 00598 getline(char_type* __s, streamsize __n, char_type __delim); 00599 00600 template<> 00601 basic_istream<char>& 00602 basic_istream<char>:: 00603 ignore(streamsize __n); 00604 00605 template<> 00606 basic_istream<char>& 00607 basic_istream<char>:: 00608 ignore(streamsize __n, int_type __delim); 00609 00610 #ifdef _GLIBCXX_USE_WCHAR_T 00611 template<> 00612 basic_istream<wchar_t>& 00613 basic_istream<wchar_t>:: 00614 getline(char_type* __s, streamsize __n, char_type __delim); 00615 00616 template<> 00617 basic_istream<wchar_t>& 00618 basic_istream<wchar_t>:: 00619 ignore(streamsize __n); 00620 00621 template<> 00622 basic_istream<wchar_t>& 00623 basic_istream<wchar_t>:: 00624 ignore(streamsize __n, int_type __delim); 00625 #endif 00626 00627 /** 00628 * @brief Performs setup work for input streams. 00629 * 00630 * Objects of this class are created before all of the standard 00631 * extractors are run. It is responsible for "exception-safe prefix and 00632 * suffix operations," although only prefix actions are currently required 00633 * by the standard. Additional actions may be added by the 00634 * implementation, and we list them in 00635 * http://gcc.gnu.org/onlinedocs/libstdc++/17_intro/howto.html#5 00636 * under [27.6] notes. 00637 */ 00638 template<typename _CharT, typename _Traits> 00639 class basic_istream<_CharT, _Traits>::sentry 00640 { 00641 public: 00642 /// Easy access to dependant types. 00643 typedef _Traits traits_type; 00644 typedef basic_streambuf<_CharT, _Traits> __streambuf_type; 00645 typedef basic_istream<_CharT, _Traits> __istream_type; 00646 typedef typename __istream_type::__ctype_type __ctype_type; 00647 typedef typename _Traits::int_type __int_type; 00648 00649 /** 00650 * @brief The constructor performs all the work. 00651 * @param is The input stream to guard. 00652 * @param noskipws Whether to consume whitespace or not. 00653 * 00654 * If the stream state is good (@a is.good() is true), then the 00655 * following actions are performed, otherwise the sentry state is 00656 * false ("not okay") and failbit is set in the stream state. 00657 * 00658 * The sentry's preparatory actions are: 00659 * 00660 * -# if the stream is tied to an output stream, @c is.tie()->flush() 00661 * is called to synchronize the output sequence 00662 * -# if @a noskipws is false, and @c ios_base::skipws is set in 00663 * @c is.flags(), the sentry extracts and discards whitespace 00664 * characters from the stream. The currently imbued locale is 00665 * used to determine whether each character is whitespace. 00666 * 00667 * If the stream state is still good, then the sentry state becomes 00668 * true ("okay"). 00669 */ 00670 explicit 00671 sentry(basic_istream<_CharT, _Traits>& __is, bool __noskipws = false); 00672 00673 /** 00674 * @brief Quick status checking. 00675 * @return The sentry state. 00676 * 00677 * For ease of use, sentries may be converted to booleans. The 00678 * return value is that of the sentry state (true == okay). 00679 */ 00680 operator bool() const 00681 { return _M_ok; } 00682 00683 private: 00684 bool _M_ok; 00685 }; 00686 00687 // [27.6.1.2.3] character extraction templates 00688 //@{ 00689 /** 00690 * @brief Character extractors 00691 * @param in An input stream. 00692 * @param c A character reference. 00693 * @return in 00694 * 00695 * Behaves like one of the formatted arithmetic extractors described in 00696 * std::basic_istream. After constructing a sentry object with good 00697 * status, this function extracts a character (if one is available) and 00698 * stores it in @a c. Otherwise, sets failbit in the input stream. 00699 */ 00700 template<typename _CharT, typename _Traits> 00701 basic_istream<_CharT, _Traits>& 00702 operator>>(basic_istream<_CharT, _Traits>& __in, _CharT& __c); 00703 00704 template<class _Traits> 00705 inline basic_istream<char, _Traits>& 00706 operator>>(basic_istream<char, _Traits>& __in, unsigned char& __c) 00707 { return (__in >> reinterpret_cast<char&>(__c)); } 00708 00709 template<class _Traits> 00710 inline basic_istream<char, _Traits>& 00711 operator>>(basic_istream<char, _Traits>& __in, signed char& __c) 00712 { return (__in >> reinterpret_cast<char&>(__c)); } 00713 //@} 00714 00715 //@{ 00716 /** 00717 * @brief Character string extractors 00718 * @param in An input stream. 00719 * @param s A pointer to a character array. 00720 * @return in 00721 * 00722 * Behaves like one of the formatted arithmetic extractors described in 00723 * std::basic_istream. After constructing a sentry object with good 00724 * status, this function extracts up to @c n characters and stores them 00725 * into the array starting at @a s. @c n is defined as: 00726 * 00727 * - if @c width() is greater than zero, @c n is width() 00728 * - otherwise @c n is "the number of elements of the largest array of 00729 * @c char_type that can store a terminating @c eos." [27.6.1.2.3]/6 00730 * 00731 * Characters are extracted and stored until one of the following happens: 00732 * - @c n-1 characters are stored 00733 * - EOF is reached 00734 * - the next character is whitespace according to the current locale 00735 * - the next character is a null byte (i.e., @c charT() ) 00736 * 00737 * @c width(0) is then called for the input stream. 00738 * 00739 * If no characters are extracted, sets failbit. 00740 */ 00741 template<typename _CharT, typename _Traits> 00742 basic_istream<_CharT, _Traits>& 00743 operator>>(basic_istream<_CharT, _Traits>& __in, _CharT* __s); 00744 00745 // Explicit specialization declaration, defined in src/istream.cc. 00746 template<> 00747 basic_istream<char>& 00748 operator>>(basic_istream<char>& __in, char* __s); 00749 00750 template<class _Traits> 00751 inline basic_istream<char, _Traits>& 00752 operator>>(basic_istream<char, _Traits>& __in, unsigned char* __s) 00753 { return (__in >> reinterpret_cast<char*>(__s)); } 00754 00755 template<class _Traits> 00756 inline basic_istream<char, _Traits>& 00757 operator>>(basic_istream<char, _Traits>& __in, signed char* __s) 00758 { return (__in >> reinterpret_cast<char*>(__s)); } 00759 //@} 00760 00761 // 27.6.1.5 Template class basic_iostream 00762 /** 00763 * @brief Merging istream and ostream capabilities. 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 _GLIBCXX_END_NAMESPACE 00834 00835 #ifndef _GLIBCXX_EXPORT_TEMPLATE 00836 # include <bits/istream.tcc> 00837 #endif 00838 00839 #endif /* _GLIBCXX_ISTREAM */