00001 // Output 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 /** @file ostream 00033 * This is a Standard C++ Library header. 00034 */ 00035 00036 // 00037 // ISO C++ 14882: 27.6.2 Output streams 00038 // 00039 00040 #ifndef _GLIBCXX_OSTREAM 00041 #define _GLIBCXX_OSTREAM 1 00042 00043 #pragma GCC system_header 00044 00045 #include <ios> 00046 #include <bits/ostream_insert.h> 00047 00048 _GLIBCXX_BEGIN_NAMESPACE(std) 00049 00050 // [27.6.2.1] Template class basic_ostream 00051 /** 00052 * @brief Controlling output. 00053 * 00054 * This is the base class for all output streams. It provides text 00055 * formatting of all builtin types, and communicates with any class 00056 * derived from basic_streambuf to do the actual output. 00057 */ 00058 template<typename _CharT, typename _Traits> 00059 class basic_ostream : 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_ostream<_CharT, _Traits> __ostream_type; 00073 typedef num_put<_CharT, ostreambuf_iterator<_CharT, _Traits> > 00074 __num_put_type; 00075 typedef ctype<_CharT> __ctype_type; 00076 00077 // [27.6.2.2] constructor/destructor 00078 /** 00079 * @brief Base constructor. 00080 * 00081 * This ctor is almost never called by the user directly, rather from 00082 * derived classes' initialization lists, which pass a pointer to 00083 * their own stream buffer. 00084 */ 00085 explicit 00086 basic_ostream(__streambuf_type* __sb) 00087 { this->init(__sb); } 00088 00089 /** 00090 * @brief Base destructor. 00091 * 00092 * This does very little apart from providing a virtual base dtor. 00093 */ 00094 virtual 00095 ~basic_ostream() { } 00096 00097 // [27.6.2.3] prefix/suffix 00098 class sentry; 00099 friend class sentry; 00100 00101 // [27.6.2.5] formatted output 00102 // [27.6.2.5.3] basic_ostream::operator<< 00103 //@{ 00104 /** 00105 * @brief Interface for manipulators. 00106 * 00107 * Manipulators such as @c std::endl and @c std::hex use these 00108 * functions in constructs like "std::cout << std::endl". For more 00109 * information, see the iomanip header. 00110 */ 00111 __ostream_type& 00112 operator<<(__ostream_type& (*__pf)(__ostream_type&)) 00113 { 00114 // _GLIBCXX_RESOLVE_LIB_DEFECTS 00115 // DR 60. What is a formatted input function? 00116 // The inserters for manipulators are *not* formatted output functions. 00117 return __pf(*this); 00118 } 00119 00120 __ostream_type& 00121 operator<<(__ios_type& (*__pf)(__ios_type&)) 00122 { 00123 // _GLIBCXX_RESOLVE_LIB_DEFECTS 00124 // DR 60. What is a formatted input function? 00125 // The inserters for manipulators are *not* formatted output functions. 00126 __pf(*this); 00127 return *this; 00128 } 00129 00130 __ostream_type& 00131 operator<<(ios_base& (*__pf) (ios_base&)) 00132 { 00133 // _GLIBCXX_RESOLVE_LIB_DEFECTS 00134 // DR 60. What is a formatted input function? 00135 // The inserters for manipulators are *not* formatted output functions. 00136 __pf(*this); 00137 return *this; 00138 } 00139 //@} 00140 00141 // [27.6.2.5.2] arithmetic inserters 00142 /** 00143 * @name Arithmetic Inserters 00144 * 00145 * All the @c operator<< functions (aka <em>formatted output 00146 * functions</em>) have some common behavior. Each starts by 00147 * constructing a temporary object of type std::basic_ostream::sentry. 00148 * This can have several effects, concluding with the setting of a 00149 * status flag; see the sentry documentation for more. 00150 * 00151 * If the sentry status is good, the function tries to generate 00152 * whatever data is appropriate for the type of the argument. 00153 * 00154 * If an exception is thrown during insertion, ios_base::badbit 00155 * will be turned on in the stream's error state without causing an 00156 * ios_base::failure to be thrown. The original exception will then 00157 * be rethrown. 00158 */ 00159 //@{ 00160 /** 00161 * @brief Basic arithmetic inserters 00162 * @param A variable of builtin type. 00163 * @return @c *this if successful 00164 * 00165 * These functions use the stream's current locale (specifically, the 00166 * @c num_get facet) to perform numeric formatting. 00167 */ 00168 __ostream_type& 00169 operator<<(long __n) 00170 { return _M_insert(__n); } 00171 00172 __ostream_type& 00173 operator<<(unsigned long __n) 00174 { return _M_insert(__n); } 00175 00176 __ostream_type& 00177 operator<<(bool __n) 00178 { return _M_insert(__n); } 00179 00180 __ostream_type& 00181 operator<<(short __n); 00182 00183 __ostream_type& 00184 operator<<(unsigned short __n) 00185 { 00186 // _GLIBCXX_RESOLVE_LIB_DEFECTS 00187 // 117. basic_ostream uses nonexistent num_put member functions. 00188 return _M_insert(static_cast<unsigned long>(__n)); 00189 } 00190 00191 __ostream_type& 00192 operator<<(int __n); 00193 00194 __ostream_type& 00195 operator<<(unsigned int __n) 00196 { 00197 // _GLIBCXX_RESOLVE_LIB_DEFECTS 00198 // 117. basic_ostream uses nonexistent num_put member functions. 00199 return _M_insert(static_cast<unsigned long>(__n)); 00200 } 00201 00202 #ifdef _GLIBCXX_USE_LONG_LONG 00203 __ostream_type& 00204 operator<<(long long __n) 00205 { return _M_insert(__n); } 00206 00207 __ostream_type& 00208 operator<<(unsigned long long __n) 00209 { return _M_insert(__n); } 00210 #endif 00211 00212 __ostream_type& 00213 operator<<(double __f) 00214 { return _M_insert(__f); } 00215 00216 __ostream_type& 00217 operator<<(float __f) 00218 { 00219 // _GLIBCXX_RESOLVE_LIB_DEFECTS 00220 // 117. basic_ostream uses nonexistent num_put member functions. 00221 return _M_insert(static_cast<double>(__f)); 00222 } 00223 00224 __ostream_type& 00225 operator<<(long double __f) 00226 { return _M_insert(__f); } 00227 00228 __ostream_type& 00229 operator<<(const void* __p) 00230 { return _M_insert(__p); } 00231 00232 /** 00233 * @brief Extracting from another streambuf. 00234 * @param sb A pointer to a streambuf 00235 * 00236 * This function behaves like one of the basic arithmetic extractors, 00237 * in that it also constructs a sentry object and has the same error 00238 * handling behavior. 00239 * 00240 * If @a sb is NULL, the stream will set failbit in its error state. 00241 * 00242 * Characters are extracted from @a sb and inserted into @c *this 00243 * until one of the following occurs: 00244 * 00245 * - the input stream reaches end-of-file, 00246 * - insertion into the output sequence fails (in this case, the 00247 * character that would have been inserted is not extracted), or 00248 * - an exception occurs while getting a character from @a sb, which 00249 * sets failbit in the error state 00250 * 00251 * If the function inserts no characters, failbit is set. 00252 */ 00253 __ostream_type& 00254 operator<<(__streambuf_type* __sb); 00255 //@} 00256 00257 // [27.6.2.6] unformatted output functions 00258 /** 00259 * @name Unformatted Output Functions 00260 * 00261 * All the unformatted output functions have some common behavior. 00262 * Each starts by constructing a temporary object of type 00263 * std::basic_ostream::sentry. This has several effects, concluding 00264 * with the setting of a status flag; see the sentry documentation 00265 * for more. 00266 * 00267 * If the sentry status is good, the function tries to generate 00268 * whatever data is appropriate for the type of the argument. 00269 * 00270 * If an exception is thrown during insertion, ios_base::badbit 00271 * will be turned on in the stream's error state. If badbit is on in 00272 * the stream's exceptions mask, the exception will be rethrown 00273 * without completing its actions. 00274 */ 00275 //@{ 00276 /** 00277 * @brief Simple insertion. 00278 * @param c The character to insert. 00279 * @return *this 00280 * 00281 * Tries to insert @a c. 00282 * 00283 * @note This function is not overloaded on signed char and 00284 * unsigned char. 00285 */ 00286 __ostream_type& 00287 put(char_type __c); 00288 00289 // Core write functionality, without sentry. 00290 void 00291 _M_write(const char_type* __s, streamsize __n) 00292 { 00293 const streamsize __put = this->rdbuf()->sputn(__s, __n); 00294 if (__put != __n) 00295 this->setstate(ios_base::badbit); 00296 } 00297 00298 /** 00299 * @brief Character string insertion. 00300 * @param s The array to insert. 00301 * @param n Maximum number of characters to insert. 00302 * @return *this 00303 * 00304 * Characters are copied from @a s and inserted into the stream until 00305 * one of the following happens: 00306 * 00307 * - @a n characters are inserted 00308 * - inserting into the output sequence fails (in this case, badbit 00309 * will be set in the stream's error state) 00310 * 00311 * @note This function is not overloaded on signed char and 00312 * unsigned char. 00313 */ 00314 __ostream_type& 00315 write(const char_type* __s, streamsize __n); 00316 //@} 00317 00318 /** 00319 * @brief Synchronizing the stream buffer. 00320 * @return *this 00321 * 00322 * If @c rdbuf() is a null pointer, changes nothing. 00323 * 00324 * Otherwise, calls @c rdbuf()->pubsync(), and if that returns -1, 00325 * sets badbit. 00326 */ 00327 __ostream_type& 00328 flush(); 00329 00330 // [27.6.2.4] seek members 00331 /** 00332 * @brief Getting the current write position. 00333 * @return A file position object. 00334 * 00335 * If @c fail() is not false, returns @c pos_type(-1) to indicate 00336 * failure. Otherwise returns @c rdbuf()->pubseekoff(0,cur,out). 00337 */ 00338 pos_type 00339 tellp(); 00340 00341 /** 00342 * @brief Changing the current write position. 00343 * @param pos A file position object. 00344 * @return *this 00345 * 00346 * If @c fail() is not true, calls @c rdbuf()->pubseekpos(pos). If 00347 * that function fails, sets failbit. 00348 */ 00349 __ostream_type& 00350 seekp(pos_type); 00351 00352 /** 00353 * @brief Changing the current write position. 00354 * @param off A file offset object. 00355 * @param dir The direction in which to seek. 00356 * @return *this 00357 * 00358 * If @c fail() is not true, calls @c rdbuf()->pubseekoff(off,dir). 00359 * If that function fails, sets failbit. 00360 */ 00361 __ostream_type& 00362 seekp(off_type, ios_base::seekdir); 00363 00364 protected: 00365 basic_ostream() 00366 { this->init(0); } 00367 00368 template<typename _ValueT> 00369 __ostream_type& 00370 _M_insert(_ValueT __v); 00371 }; 00372 00373 /** 00374 * @brief Performs setup work for output streams. 00375 * 00376 * Objects of this class are created before all of the standard 00377 * inserters are run. It is responsible for "exception-safe prefix and 00378 * suffix operations." Additional actions may be added by the 00379 * implementation, and we list them in 00380 * http://gcc.gnu.org/onlinedocs/libstdc++/17_intro/howto.html#5 00381 * under [27.6] notes. 00382 */ 00383 template <typename _CharT, typename _Traits> 00384 class basic_ostream<_CharT, _Traits>::sentry 00385 { 00386 // Data Members: 00387 bool _M_ok; 00388 basic_ostream<_CharT, _Traits>& _M_os; 00389 00390 public: 00391 /** 00392 * @brief The constructor performs preparatory work. 00393 * @param os The output stream to guard. 00394 * 00395 * If the stream state is good (@a os.good() is true), then if the 00396 * stream is tied to another output stream, @c is.tie()->flush() 00397 * is called to synchronize the output sequences. 00398 * 00399 * If the stream state is still good, then the sentry state becomes 00400 * true ("okay"). 00401 */ 00402 explicit 00403 sentry(basic_ostream<_CharT, _Traits>& __os); 00404 00405 /** 00406 * @brief Possibly flushes the stream. 00407 * 00408 * If @c ios_base::unitbuf is set in @c os.flags(), and 00409 * @c std::uncaught_exception() is true, the sentry destructor calls 00410 * @c flush() on the output stream. 00411 */ 00412 ~sentry() 00413 { 00414 // XXX MT 00415 if (bool(_M_os.flags() & ios_base::unitbuf) && !uncaught_exception()) 00416 { 00417 // Can't call flush directly or else will get into recursive lock. 00418 if (_M_os.rdbuf() && _M_os.rdbuf()->pubsync() == -1) 00419 _M_os.setstate(ios_base::badbit); 00420 } 00421 } 00422 00423 /** 00424 * @brief Quick status checking. 00425 * @return The sentry state. 00426 * 00427 * For ease of use, sentries may be converted to booleans. The 00428 * return value is that of the sentry state (true == okay). 00429 */ 00430 operator bool() const 00431 { return _M_ok; } 00432 }; 00433 00434 // [27.6.2.5.4] character insertion templates 00435 //@{ 00436 /** 00437 * @brief Character inserters 00438 * @param out An output stream. 00439 * @param c A character. 00440 * @return out 00441 * 00442 * Behaves like one of the formatted arithmetic inserters described in 00443 * std::basic_ostream. After constructing a sentry object with good 00444 * status, this function inserts a single character and any required 00445 * padding (as determined by [22.2.2.2.2]). @c out.width(0) is then 00446 * called. 00447 * 00448 * If @a c is of type @c char and the character type of the stream is not 00449 * @c char, the character is widened before insertion. 00450 */ 00451 template<typename _CharT, typename _Traits> 00452 inline basic_ostream<_CharT, _Traits>& 00453 operator<<(basic_ostream<_CharT, _Traits>& __out, _CharT __c) 00454 { return __ostream_insert(__out, &__c, 1); } 00455 00456 template<typename _CharT, typename _Traits> 00457 inline basic_ostream<_CharT, _Traits>& 00458 operator<<(basic_ostream<_CharT, _Traits>& __out, char __c) 00459 { return (__out << __out.widen(__c)); } 00460 00461 // Specialization 00462 template <class _Traits> 00463 inline basic_ostream<char, _Traits>& 00464 operator<<(basic_ostream<char, _Traits>& __out, char __c) 00465 { return __ostream_insert(__out, &__c, 1); } 00466 00467 // Signed and unsigned 00468 template<class _Traits> 00469 inline basic_ostream<char, _Traits>& 00470 operator<<(basic_ostream<char, _Traits>& __out, signed char __c) 00471 { return (__out << static_cast<char>(__c)); } 00472 00473 template<class _Traits> 00474 inline basic_ostream<char, _Traits>& 00475 operator<<(basic_ostream<char, _Traits>& __out, unsigned char __c) 00476 { return (__out << static_cast<char>(__c)); } 00477 //@} 00478 00479 //@{ 00480 /** 00481 * @brief String inserters 00482 * @param out An output stream. 00483 * @param s A character string. 00484 * @return out 00485 * @pre @a s must be a non-NULL pointer 00486 * 00487 * Behaves like one of the formatted arithmetic inserters described in 00488 * std::basic_ostream. After constructing a sentry object with good 00489 * status, this function inserts @c traits::length(s) characters starting 00490 * at @a s, widened if necessary, followed by any required padding (as 00491 * determined by [22.2.2.2.2]). @c out.width(0) is then called. 00492 */ 00493 template<typename _CharT, typename _Traits> 00494 inline basic_ostream<_CharT, _Traits>& 00495 operator<<(basic_ostream<_CharT, _Traits>& __out, const _CharT* __s) 00496 { 00497 if (!__s) 00498 __out.setstate(ios_base::badbit); 00499 else 00500 __ostream_insert(__out, __s, 00501 static_cast<streamsize>(_Traits::length(__s))); 00502 return __out; 00503 } 00504 00505 template<typename _CharT, typename _Traits> 00506 basic_ostream<_CharT, _Traits> & 00507 operator<<(basic_ostream<_CharT, _Traits>& __out, const char* __s); 00508 00509 // Partial specializations 00510 template<class _Traits> 00511 inline basic_ostream<char, _Traits>& 00512 operator<<(basic_ostream<char, _Traits>& __out, const char* __s) 00513 { 00514 if (!__s) 00515 __out.setstate(ios_base::badbit); 00516 else 00517 __ostream_insert(__out, __s, 00518 static_cast<streamsize>(_Traits::length(__s))); 00519 return __out; 00520 } 00521 00522 // Signed and unsigned 00523 template<class _Traits> 00524 inline basic_ostream<char, _Traits>& 00525 operator<<(basic_ostream<char, _Traits>& __out, const signed char* __s) 00526 { return (__out << reinterpret_cast<const char*>(__s)); } 00527 00528 template<class _Traits> 00529 inline basic_ostream<char, _Traits> & 00530 operator<<(basic_ostream<char, _Traits>& __out, const unsigned char* __s) 00531 { return (__out << reinterpret_cast<const char*>(__s)); } 00532 //@} 00533 00534 // [27.6.2.7] standard basic_ostream manipulators 00535 /** 00536 * @brief Write a newline and flush the stream. 00537 * 00538 * This manipulator is often mistakenly used when a simple newline is 00539 * desired, leading to poor buffering performance. See 00540 * http://gcc.gnu.org/onlinedocs/libstdc++/27_io/howto.html#2 for more 00541 * on this subject. 00542 */ 00543 template<typename _CharT, typename _Traits> 00544 inline basic_ostream<_CharT, _Traits>& 00545 endl(basic_ostream<_CharT, _Traits>& __os) 00546 { return flush(__os.put(__os.widen('\n'))); } 00547 00548 /** 00549 * @brief Write a null character into the output sequence. 00550 * 00551 * "Null character" is @c CharT() by definition. For CharT of @c char, 00552 * this correctly writes the ASCII @c NUL character string terminator. 00553 */ 00554 template<typename _CharT, typename _Traits> 00555 inline basic_ostream<_CharT, _Traits>& 00556 ends(basic_ostream<_CharT, _Traits>& __os) 00557 { return __os.put(_CharT()); } 00558 00559 /** 00560 * @brief Flushes the output stream. 00561 * 00562 * This manipulator simply calls the stream's @c flush() member function. 00563 */ 00564 template<typename _CharT, typename _Traits> 00565 inline basic_ostream<_CharT, _Traits>& 00566 flush(basic_ostream<_CharT, _Traits>& __os) 00567 { return __os.flush(); } 00568 00569 _GLIBCXX_END_NAMESPACE 00570 00571 #ifndef _GLIBCXX_EXPORT_TEMPLATE 00572 # include <bits/ostream.tcc> 00573 #endif 00574 00575 #endif /* _GLIBCXX_OSTREAM */