00001 // Input streams -*- C++ -*- 00002 00003 // Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006 00004 // Free Software Foundation, Inc. 00005 // 00006 // This file is part of the GNU ISO C++ Library. This library is free 00007 // software; you can redistribute it and/or modify it under the 00008 // terms of the GNU General Public License as published by the 00009 // Free Software Foundation; either version 2, or (at your option) 00010 // any later version. 00011 00012 // This library is distributed in the hope that it will be useful, 00013 // but WITHOUT ANY WARRANTY; without even the implied warranty of 00014 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00015 // GNU General Public License for more details. 00016 00017 // You should have received a copy of the GNU General Public License along 00018 // with this library; see the file COPYING. If not, write to the Free 00019 // Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, 00020 // USA. 00021 00022 // As a special exception, you may use this file as part of a free software 00023 // library without restriction. Specifically, if other files instantiate 00024 // templates or use macros or inline functions from this file, or you compile 00025 // this file and link it with other files to produce an executable, this 00026 // file does not by itself cause the resulting executable to be covered by 00027 // the GNU General Public License. This exception does not however 00028 // invalidate any other reasons why the executable file might be covered by 00029 // the GNU General Public License. 00030 00031 // 00032 // ISO C++ 14882: 27.6.1 Input streams 00033 // 00034 00035 /** @file istream 00036 * This is a Standard C++ Library header. 00037 */ 00038 00039 #ifndef _GLIBCXX_ISTREAM 00040 #define _GLIBCXX_ISTREAM 1 00041 00042 #pragma GCC system_header 00043 00044 #include <ios> 00045 #include <limits> // For numeric_limits 00046 00047 _GLIBCXX_BEGIN_NAMESPACE(std) 00048 00049 // [27.6.1.1] Template class basic_istream 00050 /** 00051 * @brief Controlling input. 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 template<typename _CharT2, typename _Traits2> 00077 friend basic_istream<_CharT2, _Traits2>& 00078 operator>>(basic_istream<_CharT2, _Traits2>&, _CharT2&); 00079 00080 template<typename _CharT2, typename _Traits2> 00081 friend basic_istream<_CharT2, _Traits2>& 00082 operator>>(basic_istream<_CharT2, _Traits2>&, _CharT2*); 00083 00084 protected: 00085 // Data Members: 00086 /** 00087 * @if maint 00088 * The number of characters extracted in the previous unformatted 00089 * function; see gcount(). 00090 * @endif 00091 */ 00092 streamsize _M_gcount; 00093 00094 public: 00095 // [27.6.1.1.1] constructor/destructor 00096 /** 00097 * @brief Base constructor. 00098 * 00099 * This ctor is almost never called by the user directly, rather from 00100 * derived classes' initialization lists, which pass a pointer to 00101 * their own stream buffer. 00102 */ 00103 explicit 00104 basic_istream(__streambuf_type* __sb): _M_gcount(streamsize(0)) 00105 { this->init(__sb); } 00106 00107 /** 00108 * @brief Base destructor. 00109 * 00110 * This does very little apart from providing a virtual base dtor. 00111 */ 00112 virtual 00113 ~basic_istream() 00114 { _M_gcount = streamsize(0); } 00115 00116 // [27.6.1.1.2] prefix/suffix 00117 class sentry; 00118 friend class sentry; 00119 00120 // [27.6.1.2] formatted input 00121 // [27.6.1.2.3] basic_istream::operator>> 00122 //@{ 00123 /** 00124 * @brief Interface for manipulators. 00125 * 00126 * Manuipulators such as @c std::ws and @c std::dec use these 00127 * functions in constructs like "std::cin >> std::ws". For more 00128 * information, see the iomanip header. 00129 */ 00130 __istream_type& 00131 operator>>(__istream_type& (*__pf)(__istream_type&)) 00132 { return __pf(*this); } 00133 00134 __istream_type& 00135 operator>>(__ios_type& (*__pf)(__ios_type&)) 00136 { 00137 __pf(*this); 00138 return *this; 00139 } 00140 00141 __istream_type& 00142 operator>>(ios_base& (*__pf)(ios_base&)) 00143 { 00144 __pf(*this); 00145 return *this; 00146 } 00147 //@} 00148 00149 // [27.6.1.2.2] arithmetic extractors 00150 /** 00151 * @name Arithmetic Extractors 00152 * 00153 * All the @c operator>> functions (aka <em>formatted input 00154 * functions</em>) have some common behavior. Each starts by 00155 * constructing a temporary object of type std::basic_istream::sentry 00156 * with the second argument (noskipws) set to false. This has several 00157 * effects, concluding with the setting of a status flag; see the 00158 * sentry documentation for more. 00159 * 00160 * If the sentry status is good, the function tries to extract 00161 * whatever data is appropriate for the type of the argument. 00162 * 00163 * If an exception is thrown during extraction, ios_base::badbit 00164 * will be turned on in the stream's error state without causing an 00165 * ios_base::failure to be thrown. The original exception will then 00166 * be rethrown. 00167 */ 00168 //@{ 00169 /** 00170 * @brief Basic arithmetic extractors 00171 * @param A variable of builtin type. 00172 * @return @c *this if successful 00173 * 00174 * These functions use the stream's current locale (specifically, the 00175 * @c num_get facet) to parse the input data. 00176 */ 00177 __istream_type& 00178 operator>>(bool& __n) 00179 { return _M_extract(__n); } 00180 00181 __istream_type& 00182 operator>>(short& __n); 00183 00184 __istream_type& 00185 operator>>(unsigned short& __n) 00186 { return _M_extract(__n); } 00187 00188 __istream_type& 00189 operator>>(int& __n); 00190 00191 __istream_type& 00192 operator>>(unsigned int& __n) 00193 { return _M_extract(__n); } 00194 00195 __istream_type& 00196 operator>>(long& __n) 00197 { return _M_extract(__n); } 00198 00199 __istream_type& 00200 operator>>(unsigned long& __n) 00201 { return _M_extract(__n); } 00202 00203 #ifdef _GLIBCXX_USE_LONG_LONG 00204 __istream_type& 00205 operator>>(long long& __n) 00206 { return _M_extract(__n); } 00207 00208 __istream_type& 00209 operator>>(unsigned long long& __n) 00210 { return _M_extract(__n); } 00211 #endif 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 __istream_type& 00226 operator>>(void*& __p) 00227 { return _M_extract(__p); } 00228 00229 /** 00230 * @brief Extracting into another streambuf. 00231 * @param sb A pointer to a streambuf 00232 * 00233 * This function behaves like one of the basic arithmetic extractors, 00234 * in that it also constructs a sentry object and has the same error 00235 * handling behavior. 00236 * 00237 * If @a sb is NULL, the stream will set failbit in its error state. 00238 * 00239 * Characters are extracted from this stream and inserted into the 00240 * @a sb streambuf until one of the following occurs: 00241 * 00242 * - the input stream reaches end-of-file, 00243 * - insertion into the output buffer fails (in this case, the 00244 * character that would have been inserted is not extracted), or 00245 * - an exception occurs (and in this case is caught) 00246 * 00247 * If the function inserts no characters, failbit is set. 00248 */ 00249 __istream_type& 00250 operator>>(__streambuf_type* __sb); 00251 //@} 00252 00253 // [27.6.1.3] unformatted input 00254 /** 00255 * @brief Character counting 00256 * @return The number of characters extracted by the previous 00257 * unformatted input function dispatched for this stream. 00258 */ 00259 streamsize 00260 gcount() const 00261 { return _M_gcount; } 00262 00263 /** 00264 * @name Unformatted Input Functions 00265 * 00266 * All the unformatted input functions have some common behavior. 00267 * Each starts by constructing a temporary object of type 00268 * std::basic_istream::sentry with the second argument (noskipws) 00269 * set to true. This has several effects, concluding with the 00270 * setting of a status flag; see the sentry documentation for more. 00271 * 00272 * If the sentry status is good, the function tries to extract 00273 * whatever data is appropriate for the type of the argument. 00274 * 00275 * The number of characters extracted is stored for later retrieval 00276 * by gcount(). 00277 * 00278 * If an exception is thrown during extraction, ios_base::badbit 00279 * will be turned on in the stream's error state without causing an 00280 * ios_base::failure to be thrown. The original exception will then 00281 * be rethrown. 00282 */ 00283 //@{ 00284 /** 00285 * @brief Simple extraction. 00286 * @return A character, or eof(). 00287 * 00288 * Tries to extract a character. If none are available, sets failbit 00289 * and returns traits::eof(). 00290 */ 00291 int_type 00292 get(); 00293 00294 /** 00295 * @brief Simple extraction. 00296 * @param c The character in which to store data. 00297 * @return *this 00298 * 00299 * Tries to extract a character and store it in @a c. If none are 00300 * available, sets failbit and returns traits::eof(). 00301 * 00302 * @note This function is not overloaded on signed char and 00303 * unsigned char. 00304 */ 00305 __istream_type& 00306 get(char_type& __c); 00307 00308 /** 00309 * @brief Simple multiple-character extraction. 00310 * @param s Pointer to an array. 00311 * @param n Maximum number of characters to store in @a s. 00312 * @param delim A "stop" character. 00313 * @return *this 00314 * 00315 * Characters are extracted and stored into @a s until one of the 00316 * following happens: 00317 * 00318 * - @c n-1 characters are stored 00319 * - the input sequence reaches EOF 00320 * - the next character equals @a delim, in which case the character 00321 * is not extracted 00322 * 00323 * If no characters are stored, failbit is set in the stream's error 00324 * state. 00325 * 00326 * In any case, a null character is stored into the next location in 00327 * the array. 00328 * 00329 * @note This function is not overloaded on signed char and 00330 * unsigned char. 00331 */ 00332 __istream_type& 00333 get(char_type* __s, streamsize __n, char_type __delim); 00334 00335 /** 00336 * @brief Simple multiple-character extraction. 00337 * @param s Pointer to an array. 00338 * @param n Maximum number of characters to store in @a s. 00339 * @return *this 00340 * 00341 * Returns @c get(s,n,widen('\n')). 00342 */ 00343 __istream_type& 00344 get(char_type* __s, streamsize __n) 00345 { return this->get(__s, __n, this->widen('\n')); } 00346 00347 /** 00348 * @brief Extraction into another streambuf. 00349 * @param sb A streambuf in which to store data. 00350 * @param delim A "stop" character. 00351 * @return *this 00352 * 00353 * Characters are extracted and inserted into @a sb until one of the 00354 * following happens: 00355 * 00356 * - the input sequence reaches EOF 00357 * - insertion into the output buffer fails (in this case, the 00358 * character that would have been inserted is not extracted) 00359 * - the next character equals @a delim (in this case, the character 00360 * is not extracted) 00361 * - an exception occurs (and in this case is caught) 00362 * 00363 * If no characters are stored, failbit is set in the stream's error 00364 * state. 00365 */ 00366 __istream_type& 00367 get(__streambuf_type& __sb, char_type __delim); 00368 00369 /** 00370 * @brief Extraction into another streambuf. 00371 * @param sb A streambuf in which to store data. 00372 * @return *this 00373 * 00374 * Returns @c get(sb,widen('\n')). 00375 */ 00376 __istream_type& 00377 get(__streambuf_type& __sb) 00378 { return this->get(__sb, this->widen('\n')); } 00379 00380 /** 00381 * @brief String extraction. 00382 * @param s A character array in which to store the data. 00383 * @param n Maximum number of characters to extract. 00384 * @param delim A "stop" character. 00385 * @return *this 00386 * 00387 * Extracts and stores characters into @a s until one of the 00388 * following happens. Note that these criteria are required to be 00389 * tested in the order listed here, to allow an input line to exactly 00390 * fill the @a s array without setting failbit. 00391 * 00392 * -# the input sequence reaches end-of-file, in which case eofbit 00393 * is set in the stream error state 00394 * -# the next character equals @c delim, in which case the character 00395 * is extracted (and therefore counted in @c gcount()) but not stored 00396 * -# @c n-1 characters are stored, in which case failbit is set 00397 * in the stream error state 00398 * 00399 * If no characters are extracted, failbit is set. (An empty line of 00400 * input should therefore not cause failbit to be set.) 00401 * 00402 * In any case, a null character is stored in the next location in 00403 * the array. 00404 */ 00405 __istream_type& 00406 getline(char_type* __s, streamsize __n, char_type __delim); 00407 00408 /** 00409 * @brief String extraction. 00410 * @param s A character array in which to store the data. 00411 * @param n Maximum number of characters to extract. 00412 * @return *this 00413 * 00414 * Returns @c getline(s,n,widen('\n')). 00415 */ 00416 __istream_type& 00417 getline(char_type* __s, streamsize __n) 00418 { return this->getline(__s, __n, this->widen('\n')); } 00419 00420 /** 00421 * @brief Discarding characters 00422 * @param n Number of characters to discard. 00423 * @param delim A "stop" character. 00424 * @return *this 00425 * 00426 * Extracts characters and throws them away until one of the 00427 * following happens: 00428 * - if @a n @c != @c std::numeric_limits<int>::max(), @a n 00429 * characters are extracted 00430 * - the input sequence reaches end-of-file 00431 * - the next character equals @a delim (in this case, the character 00432 * is extracted); note that this condition will never occur if 00433 * @a delim equals @c traits::eof(). 00434 * 00435 * NB: Provide three overloads, instead of the single function 00436 * (with defaults) mandated by the Standard: this leads to a 00437 * better performing implementation, while still conforming to 00438 * the Standard. 00439 */ 00440 __istream_type& 00441 ignore(); 00442 00443 __istream_type& 00444 ignore(streamsize __n); 00445 00446 __istream_type& 00447 ignore(streamsize __n, int_type __delim); 00448 00449 /** 00450 * @brief Looking ahead in the stream 00451 * @return The next character, or eof(). 00452 * 00453 * If, after constructing the sentry object, @c good() is false, 00454 * returns @c traits::eof(). Otherwise reads but does not extract 00455 * the next input character. 00456 */ 00457 int_type 00458 peek(); 00459 00460 /** 00461 * @brief Extraction without delimiters. 00462 * @param s A character array. 00463 * @param n Maximum number of characters to store. 00464 * @return *this 00465 * 00466 * If the stream state is @c good(), extracts characters and stores 00467 * them into @a s until one of the following happens: 00468 * - @a n characters are stored 00469 * - the input sequence reaches end-of-file, in which case the error 00470 * state is set to @c failbit|eofbit. 00471 * 00472 * @note This function is not overloaded on signed char and 00473 * unsigned char. 00474 */ 00475 __istream_type& 00476 read(char_type* __s, streamsize __n); 00477 00478 /** 00479 * @brief Extraction until the buffer is exhausted, but no more. 00480 * @param s A character array. 00481 * @param n Maximum number of characters to store. 00482 * @return The number of characters extracted. 00483 * 00484 * Extracts characters and stores them into @a s depending on the 00485 * number of characters remaining in the streambuf's buffer, 00486 * @c rdbuf()->in_avail(), called @c A here: 00487 * - if @c A @c == @c -1, sets eofbit and extracts no characters 00488 * - if @c A @c == @c 0, extracts no characters 00489 * - if @c A @c > @c 0, extracts @c min(A,n) 00490 * 00491 * The goal is to empty the current buffer, and to not request any 00492 * more from the external input sequence controlled by the streambuf. 00493 */ 00494 streamsize 00495 readsome(char_type* __s, streamsize __n); 00496 00497 /** 00498 * @brief Unextracting a single character. 00499 * @param c The character to push back into the input stream. 00500 * @return *this 00501 * 00502 * If @c rdbuf() is not null, calls @c rdbuf()->sputbackc(c). 00503 * 00504 * If @c rdbuf() is null or if @c sputbackc() fails, sets badbit in 00505 * the error state. 00506 * 00507 * @note Since no characters are extracted, the next call to 00508 * @c gcount() will return 0, as required by DR 60. 00509 */ 00510 __istream_type& 00511 putback(char_type __c); 00512 00513 /** 00514 * @brief Unextracting the previous character. 00515 * @return *this 00516 * 00517 * If @c rdbuf() is not null, calls @c rdbuf()->sungetc(c). 00518 * 00519 * If @c rdbuf() is null or if @c sungetc() fails, sets badbit in 00520 * the error state. 00521 * 00522 * @note Since no characters are extracted, the next call to 00523 * @c gcount() will return 0, as required by DR 60. 00524 */ 00525 __istream_type& 00526 unget(); 00527 00528 /** 00529 * @brief Synchronizing the stream buffer. 00530 * @return 0 on success, -1 on failure 00531 * 00532 * If @c rdbuf() is a null pointer, returns -1. 00533 * 00534 * Otherwise, calls @c rdbuf()->pubsync(), and if that returns -1, 00535 * sets badbit and returns -1. 00536 * 00537 * Otherwise, returns 0. 00538 * 00539 * @note This function does not count the number of characters 00540 * extracted, if any, and therefore does not affect the next 00541 * call to @c gcount(). 00542 */ 00543 int 00544 sync(); 00545 00546 /** 00547 * @brief Getting the current read position. 00548 * @return A file position object. 00549 * 00550 * If @c fail() is not false, returns @c pos_type(-1) to indicate 00551 * failure. Otherwise returns @c rdbuf()->pubseekoff(0,cur,in). 00552 * 00553 * @note This function does not count the number of characters 00554 * extracted, if any, and therefore does not affect the next 00555 * call to @c gcount(). 00556 */ 00557 pos_type 00558 tellg(); 00559 00560 /** 00561 * @brief Changing the current read position. 00562 * @param pos A file position object. 00563 * @return *this 00564 * 00565 * If @c fail() is not true, calls @c rdbuf()->pubseekpos(pos). If 00566 * that function fails, sets failbit. 00567 * 00568 * @note This function does not count the number of characters 00569 * extracted, if any, and therefore does not affect the next 00570 * call to @c gcount(). 00571 */ 00572 __istream_type& 00573 seekg(pos_type); 00574 00575 /** 00576 * @brief Changing the current read position. 00577 * @param off A file offset object. 00578 * @param dir The direction in which to seek. 00579 * @return *this 00580 * 00581 * If @c fail() is not true, calls @c rdbuf()->pubseekoff(off,dir). 00582 * If that function fails, sets failbit. 00583 * 00584 * @note This function does not count the number of characters 00585 * extracted, if any, and therefore does not affect the next 00586 * call to @c gcount(). 00587 */ 00588 __istream_type& 00589 seekg(off_type, ios_base::seekdir); 00590 //@} 00591 00592 protected: 00593 explicit 00594 basic_istream(): _M_gcount(streamsize(0)) { } 00595 00596 template<typename _ValueT> 00597 __istream_type& 00598 _M_extract(_ValueT& __v); 00599 }; 00600 00601 // Explicit specialization declarations, defined in src/istream.cc. 00602 template<> 00603 basic_istream<char>& 00604 basic_istream<char>:: 00605 getline(char_type* __s, streamsize __n, char_type __delim); 00606 00607 template<> 00608 basic_istream<char>& 00609 basic_istream<char>:: 00610 ignore(streamsize __n); 00611 00612 template<> 00613 basic_istream<char>& 00614 basic_istream<char>:: 00615 ignore(streamsize __n, int_type __delim); 00616 00617 #ifdef _GLIBCXX_USE_WCHAR_T 00618 template<> 00619 basic_istream<wchar_t>& 00620 basic_istream<wchar_t>:: 00621 getline(char_type* __s, streamsize __n, char_type __delim); 00622 00623 template<> 00624 basic_istream<wchar_t>& 00625 basic_istream<wchar_t>:: 00626 ignore(streamsize __n); 00627 00628 template<> 00629 basic_istream<wchar_t>& 00630 basic_istream<wchar_t>:: 00631 ignore(streamsize __n, int_type __delim); 00632 #endif 00633 00634 /** 00635 * @brief Performs setup work for input streams. 00636 * 00637 * Objects of this class are created before all of the standard 00638 * extractors are run. It is responsible for "exception-safe prefix and 00639 * suffix operations," although only prefix actions are currently required 00640 * by the standard. Additional actions may be added by the 00641 * implementation, and we list them in 00642 * http://gcc.gnu.org/onlinedocs/libstdc++/17_intro/howto.html#5 00643 * under [27.6] notes. 00644 */ 00645 template<typename _CharT, typename _Traits> 00646 class basic_istream<_CharT, _Traits>::sentry 00647 { 00648 public: 00649 /// Easy access to dependant types. 00650 typedef _Traits traits_type; 00651 typedef basic_streambuf<_CharT, _Traits> __streambuf_type; 00652 typedef basic_istream<_CharT, _Traits> __istream_type; 00653 typedef typename __istream_type::__ctype_type __ctype_type; 00654 typedef typename _Traits::int_type __int_type; 00655 00656 /** 00657 * @brief The constructor performs all the work. 00658 * @param is The input stream to guard. 00659 * @param noskipws Whether to consume whitespace or not. 00660 * 00661 * If the stream state is good (@a is.good() is true), then the 00662 * following actions are performed, otherwise the sentry state is 00663 * false ("not okay") and failbit is set in the stream state. 00664 * 00665 * The sentry's preparatory actions are: 00666 * 00667 * -# if the stream is tied to an output stream, @c is.tie()->flush() 00668 * is called to synchronize the output sequence 00669 * -# if @a noskipws is false, and @c ios_base::skipws is set in 00670 * @c is.flags(), the sentry extracts and discards whitespace 00671 * characters from the stream. The currently imbued locale is 00672 * used to determine whether each character is whitespace. 00673 * 00674 * If the stream state is still good, then the sentry state becomes 00675 * true ("okay"). 00676 */ 00677 explicit 00678 sentry(basic_istream<_CharT, _Traits>& __is, bool __noskipws = false); 00679 00680 /** 00681 * @brief Quick status checking. 00682 * @return The sentry state. 00683 * 00684 * For ease of use, sentries may be converted to booleans. The 00685 * return value is that of the sentry state (true == okay). 00686 */ 00687 operator bool() const 00688 { return _M_ok; } 00689 00690 private: 00691 bool _M_ok; 00692 }; 00693 00694 // [27.6.1.2.3] character extraction templates 00695 //@{ 00696 /** 00697 * @brief Character extractors 00698 * @param in An input stream. 00699 * @param c A character reference. 00700 * @return in 00701 * 00702 * Behaves like one of the formatted arithmetic extractors described in 00703 * std::basic_istream. After constructing a sentry object with good 00704 * status, this function extracts a character (if one is available) and 00705 * stores it in @a c. Otherwise, sets failbit in the input stream. 00706 */ 00707 template<typename _CharT, typename _Traits> 00708 basic_istream<_CharT, _Traits>& 00709 operator>>(basic_istream<_CharT, _Traits>& __in, _CharT& __c); 00710 00711 template<class _Traits> 00712 inline basic_istream<char, _Traits>& 00713 operator>>(basic_istream<char, _Traits>& __in, unsigned char& __c) 00714 { return (__in >> reinterpret_cast<char&>(__c)); } 00715 00716 template<class _Traits> 00717 inline basic_istream<char, _Traits>& 00718 operator>>(basic_istream<char, _Traits>& __in, signed char& __c) 00719 { return (__in >> reinterpret_cast<char&>(__c)); } 00720 //@} 00721 00722 //@{ 00723 /** 00724 * @brief Character string extractors 00725 * @param in An input stream. 00726 * @param s A pointer to a character array. 00727 * @return in 00728 * 00729 * Behaves like one of the formatted arithmetic extractors described in 00730 * std::basic_istream. After constructing a sentry object with good 00731 * status, this function extracts up to @c n characters and stores them 00732 * into the array starting at @a s. @c n is defined as: 00733 * 00734 * - if @c width() is greater than zero, @c n is width() 00735 * - otherwise @c n is "the number of elements of the largest array of 00736 * @c char_type that can store a terminating @c eos." [27.6.1.2.3]/6 00737 * 00738 * Characters are extracted and stored until one of the following happens: 00739 * - @c n-1 characters are stored 00740 * - EOF is reached 00741 * - the next character is whitespace according to the current locale 00742 * - the next character is a null byte (i.e., @c charT() ) 00743 * 00744 * @c width(0) is then called for the input stream. 00745 * 00746 * If no characters are extracted, sets failbit. 00747 */ 00748 template<typename _CharT, typename _Traits> 00749 basic_istream<_CharT, _Traits>& 00750 operator>>(basic_istream<_CharT, _Traits>& __in, _CharT* __s); 00751 00752 // Explicit specialization declaration, defined in src/istream.cc. 00753 template<> 00754 basic_istream<char>& 00755 operator>>(basic_istream<char>& __in, char* __s); 00756 00757 template<class _Traits> 00758 inline basic_istream<char, _Traits>& 00759 operator>>(basic_istream<char, _Traits>& __in, unsigned char* __s) 00760 { return (__in >> reinterpret_cast<char*>(__s)); } 00761 00762 template<class _Traits> 00763 inline basic_istream<char, _Traits>& 00764 operator>>(basic_istream<char, _Traits>& __in, signed char* __s) 00765 { return (__in >> reinterpret_cast<char*>(__s)); } 00766 //@} 00767 00768 // 27.6.1.5 Template class basic_iostream 00769 /** 00770 * @brief Merging istream and ostream capabilities. 00771 * 00772 * This class multiply inherits from the input and output stream classes 00773 * simply to provide a single interface. 00774 */ 00775 template<typename _CharT, typename _Traits> 00776 class basic_iostream 00777 : public basic_istream<_CharT, _Traits>, 00778 public basic_ostream<_CharT, _Traits> 00779 { 00780 public: 00781 // _GLIBCXX_RESOLVE_LIB_DEFECTS 00782 // 271. basic_iostream missing typedefs 00783 // Types (inherited): 00784 typedef _CharT char_type; 00785 typedef typename _Traits::int_type int_type; 00786 typedef typename _Traits::pos_type pos_type; 00787 typedef typename _Traits::off_type off_type; 00788 typedef _Traits traits_type; 00789 00790 // Non-standard Types: 00791 typedef basic_istream<_CharT, _Traits> __istream_type; 00792 typedef basic_ostream<_CharT, _Traits> __ostream_type; 00793 00794 /** 00795 * @brief Constructor does nothing. 00796 * 00797 * Both of the parent classes are initialized with the same 00798 * streambuf pointer passed to this constructor. 00799 */ 00800 explicit 00801 basic_iostream(basic_streambuf<_CharT, _Traits>* __sb) 00802 : __istream_type(), __ostream_type() 00803 { this->init(__sb); } 00804 00805 /** 00806 * @brief Destructor does nothing. 00807 */ 00808 virtual 00809 ~basic_iostream() { } 00810 00811 protected: 00812 explicit 00813 basic_iostream() : __istream_type(), __ostream_type() 00814 { } 00815 }; 00816 00817 // [27.6.1.4] standard basic_istream manipulators 00818 /** 00819 * @brief Quick and easy way to eat whitespace 00820 * 00821 * This manipulator extracts whitespace characters, stopping when the 00822 * next character is non-whitespace, or when the input sequence is empty. 00823 * If the sequence is empty, @c eofbit is set in the stream, but not 00824 * @c failbit. 00825 * 00826 * The current locale is used to distinguish whitespace characters. 00827 * 00828 * Example: 00829 * @code 00830 * MyClass mc; 00831 * 00832 * std::cin >> std::ws >> mc; 00833 * @endcode 00834 * will skip leading whitespace before calling operator>> on cin and your 00835 * object. Note that the same effect can be achieved by creating a 00836 * std::basic_istream::sentry inside your definition of operator>>. 00837 */ 00838 template<typename _CharT, typename _Traits> 00839 basic_istream<_CharT, _Traits>& 00840 ws(basic_istream<_CharT, _Traits>& __is); 00841 00842 _GLIBCXX_END_NAMESPACE 00843 00844 #ifndef _GLIBCXX_EXPORT_TEMPLATE 00845 # include <bits/istream.tcc> 00846 #endif 00847 00848 #endif /* _GLIBCXX_ISTREAM */