00001 // Output streams -*- C++ -*- 00002 00003 // Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003 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: 27.6.2 Output streams 00033 // 00034 00035 /** @file ostream 00036 * This is a Standard C++ Library header. 00037 */ 00038 00039 #ifndef _GLIBCXX_OSTREAM 00040 #define _GLIBCXX_OSTREAM 1 00041 00042 #pragma GCC system_header 00043 00044 #include <ios> 00045 00046 namespace std 00047 { 00048 // [27.6.2.1] Template class basic_ostream 00049 /** 00050 * @brief Controlling output. 00051 * 00052 * This is the base class for all output streams. It provides text 00053 * formatting of all builtin types, and communicates with any class 00054 * derived from basic_streambuf to do the actual output. 00055 */ 00056 template<typename _CharT, typename _Traits> 00057 class basic_ostream : virtual public basic_ios<_CharT, _Traits> 00058 { 00059 public: 00060 // Types (inherited from basic_ios (27.4.4)): 00061 typedef _CharT char_type; 00062 typedef typename _Traits::int_type int_type; 00063 typedef typename _Traits::pos_type pos_type; 00064 typedef typename _Traits::off_type off_type; 00065 typedef _Traits traits_type; 00066 00067 // Non-standard Types: 00068 typedef basic_streambuf<_CharT, _Traits> __streambuf_type; 00069 typedef basic_ios<_CharT, _Traits> __ios_type; 00070 typedef basic_ostream<_CharT, _Traits> __ostream_type; 00071 typedef num_put<_CharT, ostreambuf_iterator<_CharT, _Traits> > 00072 __num_put_type; 00073 typedef ctype<_CharT> __ctype_type; 00074 00075 template<typename _CharT2, typename _Traits2> 00076 friend basic_ostream<_CharT2, _Traits2>& 00077 operator<<(basic_ostream<_CharT2, _Traits2>&, _CharT2); 00078 00079 template<typename _Traits2> 00080 friend basic_ostream<char, _Traits2>& 00081 operator<<(basic_ostream<char, _Traits2>&, char); 00082 00083 template<typename _CharT2, typename _Traits2> 00084 friend basic_ostream<_CharT2, _Traits2>& 00085 operator<<(basic_ostream<_CharT2, _Traits2>&, const _CharT2*); 00086 00087 template<typename _Traits2> 00088 friend basic_ostream<char, _Traits2>& 00089 operator<<(basic_ostream<char, _Traits2>&, const char*); 00090 00091 template<typename _CharT2, typename _Traits2> 00092 friend basic_ostream<_CharT2, _Traits2>& 00093 operator<<(basic_ostream<_CharT2, _Traits2>&, const char*); 00094 00095 // [27.6.2.2] 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_ostream(__streambuf_type* __sb) 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_ostream() { } 00114 00115 // [27.6.2.3] prefix/suffix 00116 class sentry; 00117 friend class sentry; 00118 00119 // [27.6.2.5] formatted output 00120 // [27.6.2.5.3] basic_ostream::operator<< 00121 //@{ 00122 /** 00123 * @brief Interface for manipulators. 00124 * 00125 * Manuipulators such as @c std::endl and @c std::hex use these 00126 * functions in constructs like "std::cout << std::endl". For more 00127 * information, see the iomanip header. 00128 */ 00129 inline __ostream_type& 00130 operator<<(__ostream_type& (*__pf)(__ostream_type&)); 00131 00132 inline __ostream_type& 00133 operator<<(__ios_type& (*__pf)(__ios_type&)); 00134 00135 inline __ostream_type& 00136 operator<<(ios_base& (*__pf) (ios_base&)); 00137 //@} 00138 00139 // [27.6.2.5.2] arithmetic inserters 00140 /** 00141 * @name Arithmetic Inserters 00142 * 00143 * All the @c operator<< functions (aka <em>formatted output 00144 * functions</em>) have some common behavior. Each starts by 00145 * constructing a temporary object of type std::basic_ostream::sentry. 00146 * This can have several effects, concluding with the setting of a 00147 * status flag; see the sentry documentation for more. 00148 * 00149 * If the sentry status is good, the function tries to generate 00150 * whatever data is appropriate for the type of the argument. 00151 * 00152 * If an exception is thrown during insertion, 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 inserters 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 perform numeric formatting. 00165 */ 00166 __ostream_type& 00167 operator<<(long __n); 00168 00169 __ostream_type& 00170 operator<<(unsigned long __n); 00171 00172 __ostream_type& 00173 operator<<(bool __n); 00174 00175 __ostream_type& 00176 operator<<(short __n); 00177 00178 __ostream_type& 00179 operator<<(unsigned short __n); 00180 00181 __ostream_type& 00182 operator<<(int __n); 00183 00184 __ostream_type& 00185 operator<<(unsigned int __n); 00186 00187 #ifdef _GLIBCXX_USE_LONG_LONG 00188 __ostream_type& 00189 operator<<(long long __n); 00190 00191 __ostream_type& 00192 operator<<(unsigned long long __n); 00193 #endif 00194 00195 __ostream_type& 00196 operator<<(double __f); 00197 00198 __ostream_type& 00199 operator<<(float __f); 00200 00201 __ostream_type& 00202 operator<<(long double __f); 00203 00204 __ostream_type& 00205 operator<<(const void* __p); 00206 00207 /** 00208 * @brief Extracting from another streambuf. 00209 * @param sb A pointer to a streambuf 00210 * 00211 * This function behaves like one of the basic arithmetic extractors, 00212 * in that it also constructs a sentry object and has the same error 00213 * handling behavior. 00214 * 00215 * If @a sb is NULL, the stream will set failbit in its error state. 00216 * 00217 * Characters are extracted from @a sb and inserted into @c *this 00218 * until one of the following occurs: 00219 * 00220 * - the input stream reaches end-of-file, 00221 * - insertion into the output sequence fails (in this case, the 00222 * character that would have been inserted is not extracted), or 00223 * - an exception occurs while getting a character from @a sb, which 00224 * sets failbit in the error state 00225 * 00226 * If the function inserts no characters, failbit is set. 00227 */ 00228 __ostream_type& 00229 operator<<(__streambuf_type* __sb); 00230 //@} 00231 00232 // [27.6.2.6] unformatted output functions 00233 /** 00234 * @name Unformatted Output Functions 00235 * 00236 * All the unformatted output functions have some common behavior. 00237 * Each starts by constructing a temporary object of type 00238 * std::basic_ostream::sentry. This has several effects, concluding 00239 * with the setting of a status flag; see the sentry documentation 00240 * for more. 00241 * 00242 * If the sentry status is good, the function tries to generate 00243 * whatever data is appropriate for the type of the argument. 00244 * 00245 * If an exception is thrown during insertion, ios_base::badbit 00246 * will be turned on in the stream's error state. If badbit is on in 00247 * the stream's exceptions mask, the exception will be rethrown 00248 * without completing its actions. 00249 */ 00250 //@{ 00251 /** 00252 * @brief Simple insertion. 00253 * @param c The character to insert. 00254 * @return *this 00255 * 00256 * Tries to insert @a c. 00257 * 00258 * @note This function is not overloaded on signed char and 00259 * unsigned char. 00260 */ 00261 __ostream_type& 00262 put(char_type __c); 00263 00264 // Core write functionality, without sentry. 00265 void 00266 _M_write(const char_type* __s, streamsize __n) 00267 { 00268 streamsize __put = this->rdbuf()->sputn(__s, __n); 00269 if (__put != __n) 00270 this->setstate(ios_base::badbit); 00271 } 00272 00273 /** 00274 * @brief Character string insertion. 00275 * @param s The array to insert. 00276 * @param n Maximum number of characters to insert. 00277 * @return *this 00278 * 00279 * Characters are copied from @a s and inserted into the stream until 00280 * one of the following happens: 00281 * 00282 * - @a n characters are inserted 00283 * - inserting into the output sequence fails (in this case, badbit 00284 * will be set in the stream's error state) 00285 * 00286 * @note This function is not overloaded on signed char and 00287 * unsigned char. 00288 */ 00289 __ostream_type& 00290 write(const char_type* __s, streamsize __n); 00291 //@} 00292 00293 /** 00294 * @brief Synchronizing the stream buffer. 00295 * @return *this 00296 * 00297 * If @c rdbuf() is a null pointer, changes nothing. 00298 * 00299 * Otherwise, calls @c rdbuf()->pubsync(), and if that returns -1, 00300 * sets badbit. 00301 */ 00302 __ostream_type& 00303 flush(); 00304 00305 // [27.6.2.4] seek members 00306 /** 00307 * @brief Getting the current write position. 00308 * @return A file position object. 00309 * 00310 * If @c fail() is not false, returns @c pos_type(-1) to indicate 00311 * failure. Otherwise returns @c rdbuf()->pubseekoff(0,cur,out). 00312 */ 00313 pos_type 00314 tellp(); 00315 00316 /** 00317 * @brief Changing the current write position. 00318 * @param pos A file position object. 00319 * @return *this 00320 * 00321 * If @c fail() is not true, calls @c rdbuf()->pubseekpos(pos). If 00322 * that function fails, sets failbit. 00323 */ 00324 __ostream_type& 00325 seekp(pos_type); 00326 00327 /** 00328 * @brief Changing the current write position. 00329 * @param off A file offset object. 00330 * @param dir The direction in which to seek. 00331 * @return *this 00332 * 00333 * If @c fail() is not true, calls @c rdbuf()->pubseekoff(off,dir). 00334 * If that function fails, sets failbit. 00335 */ 00336 __ostream_type& 00337 seekp(off_type, ios_base::seekdir); 00338 00339 protected: 00340 explicit 00341 basic_ostream() { } 00342 }; 00343 00344 /** 00345 * @brief Performs setup work for output streams. 00346 * 00347 * Objects of this class are created before all of the standard 00348 * inserters are run. It is responsible for "exception-safe prefix and 00349 * suffix operations." Additional actions may be added by the 00350 * implementation, and we list them in 00351 * http://gcc.gnu.org/onlinedocs/libstdc++/17_intro/howto.html#5 00352 * under [27.6] notes. 00353 */ 00354 template <typename _CharT, typename _Traits> 00355 class basic_ostream<_CharT, _Traits>::sentry 00356 { 00357 // Data Members: 00358 bool _M_ok; 00359 basic_ostream<_CharT,_Traits>& _M_os; 00360 00361 public: 00362 /** 00363 * @brief The constructor performs preparatory work. 00364 * @param os The output stream to guard. 00365 * 00366 * If the stream state is good (@a os.good() is true), then if the 00367 * stream is tied to another output stream, @c is.tie()->flush() 00368 * is called to synchronize the output sequences. 00369 * 00370 * If the stream state is still good, then the sentry state becomes 00371 * true ("okay"). 00372 */ 00373 explicit 00374 sentry(basic_ostream<_CharT,_Traits>& __os); 00375 00376 /** 00377 * @brief Possibly flushes the stream. 00378 * 00379 * If @c ios_base::unitbuf is set in @c os.flags(), and 00380 * @c std::uncaught_exception() is true, the sentry destructor calls 00381 * @c flush() on the output stream. 00382 */ 00383 ~sentry() 00384 { 00385 // XXX MT 00386 if (_M_os.flags() & ios_base::unitbuf && !uncaught_exception()) 00387 { 00388 // Can't call flush directly or else will get into recursive lock. 00389 if (_M_os.rdbuf() && _M_os.rdbuf()->pubsync() == -1) 00390 _M_os.setstate(ios_base::badbit); 00391 } 00392 } 00393 00394 /** 00395 * @brief Quick status checking. 00396 * @return The sentry state. 00397 * 00398 * For ease of use, sentries may be converted to booleans. The 00399 * return value is that of the sentry state (true == okay). 00400 */ 00401 operator bool() const 00402 { return _M_ok; } 00403 }; 00404 00405 // [27.6.2.5.4] character insertion templates 00406 //@{ 00407 /** 00408 * @brief Character inserters 00409 * @param out An output stream. 00410 * @param c A character. 00411 * @return out 00412 * 00413 * Behaves like one of the formatted arithmetic inserters described in 00414 * std::basic_ostream. After constructing a sentry object with good 00415 * status, this function inserts a single character and any required 00416 * padding (as determined by [22.2.2.2.2]). @c out.width(0) is then 00417 * called. 00418 * 00419 * If @a c is of type @c char and the character type of the stream is not 00420 * @c char, the character is widened before insertion. 00421 */ 00422 template<typename _CharT, typename _Traits> 00423 basic_ostream<_CharT, _Traits>& 00424 operator<<(basic_ostream<_CharT, _Traits>& __out, _CharT __c); 00425 00426 template<typename _CharT, typename _Traits> 00427 basic_ostream<_CharT, _Traits>& 00428 operator<<(basic_ostream<_CharT, _Traits>& __out, char __c) 00429 { return (__out << __out.widen(__c)); } 00430 00431 // Specialization 00432 template <class _Traits> 00433 basic_ostream<char, _Traits>& 00434 operator<<(basic_ostream<char, _Traits>& __out, char __c); 00435 00436 // Signed and unsigned 00437 template<class _Traits> 00438 basic_ostream<char, _Traits>& 00439 operator<<(basic_ostream<char, _Traits>& __out, signed char __c) 00440 { return (__out << static_cast<char>(__c)); } 00441 00442 template<class _Traits> 00443 basic_ostream<char, _Traits>& 00444 operator<<(basic_ostream<char, _Traits>& __out, unsigned char __c) 00445 { return (__out << static_cast<char>(__c)); } 00446 //@} 00447 00448 //@{ 00449 /** 00450 * @brief String inserters 00451 * @param out An output stream. 00452 * @param s A character string. 00453 * @return out 00454 * @pre @a s must be a non-NULL pointer 00455 * 00456 * Behaves like one of the formatted arithmetic inserters described in 00457 * std::basic_ostream. After constructing a sentry object with good 00458 * status, this function inserts @c traits::length(s) characters starting 00459 * at @a s, widened if necessary, followed by any required padding (as 00460 * determined by [22.2.2.2.2]). @c out.width(0) is then called. 00461 */ 00462 template<typename _CharT, typename _Traits> 00463 basic_ostream<_CharT, _Traits>& 00464 operator<<(basic_ostream<_CharT, _Traits>& __out, const _CharT* __s); 00465 00466 template<typename _CharT, typename _Traits> 00467 basic_ostream<_CharT, _Traits> & 00468 operator<<(basic_ostream<_CharT, _Traits>& __out, const char* __s); 00469 00470 // Partial specializationss 00471 template<class _Traits> 00472 basic_ostream<char, _Traits>& 00473 operator<<(basic_ostream<char, _Traits>& __out, const char* __s); 00474 00475 // Signed and unsigned 00476 template<class _Traits> 00477 basic_ostream<char, _Traits>& 00478 operator<<(basic_ostream<char, _Traits>& __out, const signed char* __s) 00479 { return (__out << reinterpret_cast<const char*>(__s)); } 00480 00481 template<class _Traits> 00482 basic_ostream<char, _Traits> & 00483 operator<<(basic_ostream<char, _Traits>& __out, const unsigned char* __s) 00484 { return (__out << reinterpret_cast<const char*>(__s)); } 00485 //@} 00486 00487 // [27.6.2.7] standard basic_ostream manipulators 00488 /** 00489 * @brief Write a newline and flush the stream. 00490 * 00491 * This manipulator is often mistakenly used when a simple newline is 00492 * desired, leading to poor buffering performance. See 00493 * http://gcc.gnu.org/onlinedocs/libstdc++/27_io/howto.html#2 for more 00494 * on this subject. 00495 */ 00496 template<typename _CharT, typename _Traits> 00497 basic_ostream<_CharT, _Traits>& 00498 endl(basic_ostream<_CharT, _Traits>& __os) 00499 { return flush(__os.put(__os.widen('\n'))); } 00500 00501 /** 00502 * @brief Write a null character into the output sequence. 00503 * 00504 * "Null character" is @c CharT() by definition. For CharT of @c char, 00505 * this correctly writes the ASCII @c NUL character string terminator. 00506 */ 00507 template<typename _CharT, typename _Traits> 00508 basic_ostream<_CharT, _Traits>& 00509 ends(basic_ostream<_CharT, _Traits>& __os) 00510 { return __os.put(_CharT()); } 00511 00512 /** 00513 * @brief Flushes the output stream. 00514 * 00515 * This manipulator simply calls the stream's @c flush() member function. 00516 */ 00517 template<typename _CharT, typename _Traits> 00518 basic_ostream<_CharT, _Traits>& 00519 flush(basic_ostream<_CharT, _Traits>& __os) 00520 { return __os.flush(); } 00521 00522 } // namespace std 00523 00524 #ifndef _GLIBCXX_EXPORT_TEMPLATE 00525 # include <bits/ostream.tcc> 00526 #endif 00527 00528 #endif /* _GLIBCXX_OSTREAM */