00001 // Output streams -*- C++ -*- 00002 00003 // Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 00004 // 2006, 2007, 2008, 2009, 2010, 2011 00005 // Free Software Foundation, Inc. 00006 // 00007 // This file is part of the GNU ISO C++ Library. This library is free 00008 // software; you can redistribute it and/or modify it under the 00009 // terms of the GNU General Public License as published by the 00010 // Free Software Foundation; either version 3, or (at your option) 00011 // any later version. 00012 00013 // This library is distributed in the hope that it will be useful, 00014 // but WITHOUT ANY WARRANTY; without even the implied warranty of 00015 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00016 // GNU General Public License for more details. 00017 00018 // Under Section 7 of GPL version 3, you are granted additional 00019 // permissions described in the GCC Runtime Library Exception, version 00020 // 3.1, as published by the Free Software Foundation. 00021 00022 // You should have received a copy of the GNU General Public License and 00023 // a copy of the GCC Runtime Library Exception along with this program; 00024 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 00025 // <http://www.gnu.org/licenses/>. 00026 00027 /** @file include/ostream 00028 * This is a Standard C++ Library header. 00029 */ 00030 00031 // 00032 // ISO C++ 14882: 27.6.2 Output streams 00033 // 00034 00035 #ifndef _GLIBCXX_OSTREAM 00036 #define _GLIBCXX_OSTREAM 1 00037 00038 #pragma GCC system_header 00039 00040 #include <ios> 00041 #include <bits/ostream_insert.h> 00042 00043 namespace std _GLIBCXX_VISIBILITY(default) 00044 { 00045 _GLIBCXX_BEGIN_NAMESPACE_VERSION 00046 00047 // [27.6.2.1] Template class basic_ostream 00048 /** 00049 * @brief Controlling output. 00050 * @ingroup io 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 // [27.6.2.2] constructor/destructor 00076 /** 00077 * @brief Base constructor. 00078 * 00079 * This ctor is almost never called by the user directly, rather from 00080 * derived classes' initialization lists, which pass a pointer to 00081 * their own stream buffer. 00082 */ 00083 explicit 00084 basic_ostream(__streambuf_type* __sb) 00085 { this->init(__sb); } 00086 00087 /** 00088 * @brief Base destructor. 00089 * 00090 * This does very little apart from providing a virtual base dtor. 00091 */ 00092 virtual 00093 ~basic_ostream() { } 00094 00095 // [27.6.2.3] prefix/suffix 00096 class sentry; 00097 friend class sentry; 00098 00099 // [27.6.2.5] formatted output 00100 // [27.6.2.5.3] basic_ostream::operator<< 00101 //@{ 00102 /** 00103 * @brief Interface for manipulators. 00104 * 00105 * Manipulators such as @c std::endl and @c std::hex use these 00106 * functions in constructs like "std::cout << std::endl". For more 00107 * information, see the iomanip header. 00108 */ 00109 __ostream_type& 00110 operator<<(__ostream_type& (*__pf)(__ostream_type&)) 00111 { 00112 // _GLIBCXX_RESOLVE_LIB_DEFECTS 00113 // DR 60. What is a formatted input function? 00114 // The inserters for manipulators are *not* formatted output functions. 00115 return __pf(*this); 00116 } 00117 00118 __ostream_type& 00119 operator<<(__ios_type& (*__pf)(__ios_type&)) 00120 { 00121 // _GLIBCXX_RESOLVE_LIB_DEFECTS 00122 // DR 60. What is a formatted input function? 00123 // The inserters for manipulators are *not* formatted output functions. 00124 __pf(*this); 00125 return *this; 00126 } 00127 00128 __ostream_type& 00129 operator<<(ios_base& (*__pf) (ios_base&)) 00130 { 00131 // _GLIBCXX_RESOLVE_LIB_DEFECTS 00132 // DR 60. What is a formatted input function? 00133 // The inserters for manipulators are *not* formatted output functions. 00134 __pf(*this); 00135 return *this; 00136 } 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 { return _M_insert(__n); } 00169 00170 __ostream_type& 00171 operator<<(unsigned long __n) 00172 { return _M_insert(__n); } 00173 00174 __ostream_type& 00175 operator<<(bool __n) 00176 { return _M_insert(__n); } 00177 00178 __ostream_type& 00179 operator<<(short __n); 00180 00181 __ostream_type& 00182 operator<<(unsigned short __n) 00183 { 00184 // _GLIBCXX_RESOLVE_LIB_DEFECTS 00185 // 117. basic_ostream uses nonexistent num_put member functions. 00186 return _M_insert(static_cast<unsigned long>(__n)); 00187 } 00188 00189 __ostream_type& 00190 operator<<(int __n); 00191 00192 __ostream_type& 00193 operator<<(unsigned int __n) 00194 { 00195 // _GLIBCXX_RESOLVE_LIB_DEFECTS 00196 // 117. basic_ostream uses nonexistent num_put member functions. 00197 return _M_insert(static_cast<unsigned long>(__n)); 00198 } 00199 00200 #ifdef _GLIBCXX_USE_LONG_LONG 00201 __ostream_type& 00202 operator<<(long long __n) 00203 { return _M_insert(__n); } 00204 00205 __ostream_type& 00206 operator<<(unsigned long long __n) 00207 { return _M_insert(__n); } 00208 #endif 00209 00210 __ostream_type& 00211 operator<<(double __f) 00212 { return _M_insert(__f); } 00213 00214 __ostream_type& 00215 operator<<(float __f) 00216 { 00217 // _GLIBCXX_RESOLVE_LIB_DEFECTS 00218 // 117. basic_ostream uses nonexistent num_put member functions. 00219 return _M_insert(static_cast<double>(__f)); 00220 } 00221 00222 __ostream_type& 00223 operator<<(long double __f) 00224 { return _M_insert(__f); } 00225 00226 __ostream_type& 00227 operator<<(const void* __p) 00228 { return _M_insert(__p); } 00229 00230 /** 00231 * @brief Extracting from another streambuf. 00232 * @param sb A pointer to a streambuf 00233 * 00234 * This function behaves like one of the basic arithmetic extractors, 00235 * in that it also constructs a sentry object and has the same error 00236 * handling behavior. 00237 * 00238 * If @a sb is NULL, the stream will set failbit in its error state. 00239 * 00240 * Characters are extracted from @a sb and inserted into @c *this 00241 * until one of the following occurs: 00242 * 00243 * - the input stream reaches end-of-file, 00244 * - insertion into the output sequence fails (in this case, the 00245 * character that would have been inserted is not extracted), or 00246 * - an exception occurs while getting a character from @a sb, which 00247 * sets failbit in the error state 00248 * 00249 * If the function inserts no characters, failbit is set. 00250 */ 00251 __ostream_type& 00252 operator<<(__streambuf_type* __sb); 00253 //@} 00254 00255 // [27.6.2.6] unformatted output functions 00256 /** 00257 * @name Unformatted Output Functions 00258 * 00259 * All the unformatted output functions have some common behavior. 00260 * Each starts by constructing a temporary object of type 00261 * std::basic_ostream::sentry. This has several effects, concluding 00262 * with the setting of a status flag; see the sentry documentation 00263 * for more. 00264 * 00265 * If the sentry status is good, the function tries to generate 00266 * whatever data is appropriate for the type of the argument. 00267 * 00268 * If an exception is thrown during insertion, ios_base::badbit 00269 * will be turned on in the stream's error state. If badbit is on in 00270 * the stream's exceptions mask, the exception will be rethrown 00271 * without completing its actions. 00272 */ 00273 //@{ 00274 /** 00275 * @brief Simple insertion. 00276 * @param c The character to insert. 00277 * @return *this 00278 * 00279 * Tries to insert @a c. 00280 * 00281 * @note This function is not overloaded on signed char and 00282 * unsigned char. 00283 */ 00284 __ostream_type& 00285 put(char_type __c); 00286 00287 // Core write functionality, without sentry. 00288 void 00289 _M_write(const char_type* __s, streamsize __n) 00290 { 00291 const streamsize __put = this->rdbuf()->sputn(__s, __n); 00292 if (__put != __n) 00293 this->setstate(ios_base::badbit); 00294 } 00295 00296 /** 00297 * @brief Character string insertion. 00298 * @param s The array to insert. 00299 * @param n Maximum number of characters to insert. 00300 * @return *this 00301 * 00302 * Characters are copied from @a s and inserted into the stream until 00303 * one of the following happens: 00304 * 00305 * - @a n characters are inserted 00306 * - inserting into the output sequence fails (in this case, badbit 00307 * will be set in the stream's error state) 00308 * 00309 * @note This function is not overloaded on signed char and 00310 * unsigned char. 00311 */ 00312 __ostream_type& 00313 write(const char_type* __s, streamsize __n); 00314 //@} 00315 00316 /** 00317 * @brief Synchronizing the stream buffer. 00318 * @return *this 00319 * 00320 * If @c rdbuf() is a null pointer, changes nothing. 00321 * 00322 * Otherwise, calls @c rdbuf()->pubsync(), and if that returns -1, 00323 * sets badbit. 00324 */ 00325 __ostream_type& 00326 flush(); 00327 00328 // [27.6.2.4] seek members 00329 /** 00330 * @brief Getting the current write position. 00331 * @return A file position object. 00332 * 00333 * If @c fail() is not false, returns @c pos_type(-1) to indicate 00334 * failure. Otherwise returns @c rdbuf()->pubseekoff(0,cur,out). 00335 */ 00336 pos_type 00337 tellp(); 00338 00339 /** 00340 * @brief Changing the current write position. 00341 * @param pos A file position object. 00342 * @return *this 00343 * 00344 * If @c fail() is not true, calls @c rdbuf()->pubseekpos(pos). If 00345 * that function fails, sets failbit. 00346 */ 00347 __ostream_type& 00348 seekp(pos_type); 00349 00350 /** 00351 * @brief Changing the current write position. 00352 * @param off A file offset object. 00353 * @param dir The direction in which to seek. 00354 * @return *this 00355 * 00356 * If @c fail() is not true, calls @c rdbuf()->pubseekoff(off,dir). 00357 * If that function fails, sets failbit. 00358 */ 00359 __ostream_type& 00360 seekp(off_type, ios_base::seekdir); 00361 00362 protected: 00363 basic_ostream() 00364 { this->init(0); } 00365 00366 template<typename _ValueT> 00367 __ostream_type& 00368 _M_insert(_ValueT __v); 00369 }; 00370 00371 /** 00372 * @brief Performs setup work for output streams. 00373 * 00374 * Objects of this class are created before all of the standard 00375 * inserters are run. It is responsible for <em>exception-safe prefix and 00376 * suffix operations</em>. 00377 */ 00378 template <typename _CharT, typename _Traits> 00379 class basic_ostream<_CharT, _Traits>::sentry 00380 { 00381 // Data Members. 00382 bool _M_ok; 00383 basic_ostream<_CharT, _Traits>& _M_os; 00384 00385 public: 00386 /** 00387 * @brief The constructor performs preparatory work. 00388 * @param os The output stream to guard. 00389 * 00390 * If the stream state is good (@a os.good() is true), then if the 00391 * stream is tied to another output stream, @c is.tie()->flush() 00392 * is called to synchronize the output sequences. 00393 * 00394 * If the stream state is still good, then the sentry state becomes 00395 * true (@a okay). 00396 */ 00397 explicit 00398 sentry(basic_ostream<_CharT, _Traits>& __os); 00399 00400 /** 00401 * @brief Possibly flushes the stream. 00402 * 00403 * If @c ios_base::unitbuf is set in @c os.flags(), and 00404 * @c std::uncaught_exception() is true, the sentry destructor calls 00405 * @c flush() on the output stream. 00406 */ 00407 ~sentry() 00408 { 00409 // XXX MT 00410 if (bool(_M_os.flags() & ios_base::unitbuf) && !uncaught_exception()) 00411 { 00412 // Can't call flush directly or else will get into recursive lock. 00413 if (_M_os.rdbuf() && _M_os.rdbuf()->pubsync() == -1) 00414 _M_os.setstate(ios_base::badbit); 00415 } 00416 } 00417 00418 /** 00419 * @brief Quick status checking. 00420 * @return The sentry state. 00421 * 00422 * For ease of use, sentries may be converted to booleans. The 00423 * return value is that of the sentry state (true == okay). 00424 */ 00425 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 00426 explicit 00427 #endif 00428 operator bool() const 00429 { return _M_ok; } 00430 }; 00431 00432 // [27.6.2.5.4] character insertion templates 00433 //@{ 00434 /** 00435 * @brief Character inserters 00436 * @param out An output stream. 00437 * @param c A character. 00438 * @return out 00439 * 00440 * Behaves like one of the formatted arithmetic inserters described in 00441 * std::basic_ostream. After constructing a sentry object with good 00442 * status, this function inserts a single character and any required 00443 * padding (as determined by [22.2.2.2.2]). @c out.width(0) is then 00444 * called. 00445 * 00446 * If @a c is of type @c char and the character type of the stream is not 00447 * @c char, the character is widened before insertion. 00448 */ 00449 template<typename _CharT, typename _Traits> 00450 inline basic_ostream<_CharT, _Traits>& 00451 operator<<(basic_ostream<_CharT, _Traits>& __out, _CharT __c) 00452 { return __ostream_insert(__out, &__c, 1); } 00453 00454 template<typename _CharT, typename _Traits> 00455 inline basic_ostream<_CharT, _Traits>& 00456 operator<<(basic_ostream<_CharT, _Traits>& __out, char __c) 00457 { return (__out << __out.widen(__c)); } 00458 00459 // Specialization 00460 template <class _Traits> 00461 inline basic_ostream<char, _Traits>& 00462 operator<<(basic_ostream<char, _Traits>& __out, char __c) 00463 { return __ostream_insert(__out, &__c, 1); } 00464 00465 // Signed and unsigned 00466 template<class _Traits> 00467 inline basic_ostream<char, _Traits>& 00468 operator<<(basic_ostream<char, _Traits>& __out, signed char __c) 00469 { return (__out << static_cast<char>(__c)); } 00470 00471 template<class _Traits> 00472 inline basic_ostream<char, _Traits>& 00473 operator<<(basic_ostream<char, _Traits>& __out, unsigned char __c) 00474 { return (__out << static_cast<char>(__c)); } 00475 //@} 00476 00477 //@{ 00478 /** 00479 * @brief String inserters 00480 * @param out An output stream. 00481 * @param s A character string. 00482 * @return out 00483 * @pre @a s must be a non-NULL pointer 00484 * 00485 * Behaves like one of the formatted arithmetic inserters described in 00486 * std::basic_ostream. After constructing a sentry object with good 00487 * status, this function inserts @c traits::length(s) characters starting 00488 * at @a s, widened if necessary, followed by any required padding (as 00489 * determined by [22.2.2.2.2]). @c out.width(0) is then called. 00490 */ 00491 template<typename _CharT, typename _Traits> 00492 inline basic_ostream<_CharT, _Traits>& 00493 operator<<(basic_ostream<_CharT, _Traits>& __out, const _CharT* __s) 00494 { 00495 if (!__s) 00496 __out.setstate(ios_base::badbit); 00497 else 00498 __ostream_insert(__out, __s, 00499 static_cast<streamsize>(_Traits::length(__s))); 00500 return __out; 00501 } 00502 00503 template<typename _CharT, typename _Traits> 00504 basic_ostream<_CharT, _Traits> & 00505 operator<<(basic_ostream<_CharT, _Traits>& __out, const char* __s); 00506 00507 // Partial specializations 00508 template<class _Traits> 00509 inline basic_ostream<char, _Traits>& 00510 operator<<(basic_ostream<char, _Traits>& __out, const char* __s) 00511 { 00512 if (!__s) 00513 __out.setstate(ios_base::badbit); 00514 else 00515 __ostream_insert(__out, __s, 00516 static_cast<streamsize>(_Traits::length(__s))); 00517 return __out; 00518 } 00519 00520 // Signed and unsigned 00521 template<class _Traits> 00522 inline basic_ostream<char, _Traits>& 00523 operator<<(basic_ostream<char, _Traits>& __out, const signed char* __s) 00524 { return (__out << reinterpret_cast<const char*>(__s)); } 00525 00526 template<class _Traits> 00527 inline basic_ostream<char, _Traits> & 00528 operator<<(basic_ostream<char, _Traits>& __out, const unsigned char* __s) 00529 { return (__out << reinterpret_cast<const char*>(__s)); } 00530 //@} 00531 00532 // [27.6.2.7] standard basic_ostream manipulators 00533 /** 00534 * @brief Write a newline and flush the stream. 00535 * 00536 * This manipulator is often mistakenly used when a simple newline is 00537 * desired, leading to poor buffering performance. See 00538 * http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt11ch25s02.html 00539 * for more on this subject. 00540 */ 00541 template<typename _CharT, typename _Traits> 00542 inline basic_ostream<_CharT, _Traits>& 00543 endl(basic_ostream<_CharT, _Traits>& __os) 00544 { return flush(__os.put(__os.widen('\n'))); } 00545 00546 /** 00547 * @brief Write a null character into the output sequence. 00548 * 00549 * <em>Null character</em> is @c CharT() by definition. For CharT of @c char, 00550 * this correctly writes the ASCII @c NUL character string terminator. 00551 */ 00552 template<typename _CharT, typename _Traits> 00553 inline basic_ostream<_CharT, _Traits>& 00554 ends(basic_ostream<_CharT, _Traits>& __os) 00555 { return __os.put(_CharT()); } 00556 00557 /** 00558 * @brief Flushes the output stream. 00559 * 00560 * This manipulator simply calls the stream's @c flush() member function. 00561 */ 00562 template<typename _CharT, typename _Traits> 00563 inline basic_ostream<_CharT, _Traits>& 00564 flush(basic_ostream<_CharT, _Traits>& __os) 00565 { return __os.flush(); } 00566 00567 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 00568 // [27.7.2.9] Rvalue stream insertion 00569 /** 00570 * @brief Generic inserter for rvalue stream 00571 * @param os An input stream. 00572 * @param x A reference to the object being inserted. 00573 * @return os 00574 * 00575 * This is just a forwarding function to allow insertion to 00576 * rvalue streams since they won't bind to the inserter functions 00577 * that take an lvalue reference. 00578 */ 00579 template<typename _CharT, typename _Traits, typename _Tp> 00580 inline basic_ostream<_CharT, _Traits>& 00581 operator<<(basic_ostream<_CharT, _Traits>&& __os, const _Tp& __x) 00582 { return (__os << __x); } 00583 #endif // __GXX_EXPERIMENTAL_CXX0X__ 00584 00585 _GLIBCXX_END_NAMESPACE_VERSION 00586 } // namespace 00587 00588 #include <bits/ostream.tcc> 00589 00590 #endif /* _GLIBCXX_OSTREAM */