1 // Output streams -*- C++ -*- 2 3 // Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 4 // 2006, 2007, 2008, 2009, 2010, 2011 5 // Free Software Foundation, Inc. 6 // 7 // This file is part of the GNU ISO C++ Library. This library is free 8 // software; you can redistribute it and/or modify it under the 9 // terms of the GNU General Public License as published by the 10 // Free Software Foundation; either version 3, or (at your option) 11 // any later version. 12 13 // This library is distributed in the hope that it will be useful, 14 // but WITHOUT ANY WARRANTY; without even the implied warranty of 15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 // GNU General Public License for more details. 17 18 // Under Section 7 of GPL version 3, you are granted additional 19 // permissions described in the GCC Runtime Library Exception, version 20 // 3.1, as published by the Free Software Foundation. 21 22 // You should have received a copy of the GNU General Public License and 23 // a copy of the GCC Runtime Library Exception along with this program; 24 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 25 // <http://www.gnu.org/licenses/>. 26 27 /** @file include/ostream 28 * This is a Standard C++ Library header. 29 */ 30 31 // 32 // ISO C++ 14882: 27.6.2 Output streams 33 // 34 35 #ifndef _GLIBCXX_OSTREAM 36 #define _GLIBCXX_OSTREAM 1 37 38 #pragma GCC system_header 39 40 #include <ios> 41 #include <bits/ostream_insert.h> 42 43 namespace std _GLIBCXX_VISIBILITY(default) 44 { 45 _GLIBCXX_BEGIN_NAMESPACE_VERSION 46 47 // [27.6.2.1] Template class basic_ostream 48 /** 49 * @brief Controlling output. 50 * @ingroup io 51 * 52 * This is the base class for all output streams. It provides text 53 * formatting of all builtin types, and communicates with any class 54 * derived from basic_streambuf to do the actual output. 55 */ 56 template<typename _CharT, typename _Traits> 57 class basic_ostream : virtual public basic_ios<_CharT, _Traits> 58 { 59 public: 60 // Types (inherited from basic_ios (27.4.4)): 61 typedef _CharT char_type; 62 typedef typename _Traits::int_type int_type; 63 typedef typename _Traits::pos_type pos_type; 64 typedef typename _Traits::off_type off_type; 65 typedef _Traits traits_type; 66 67 // Non-standard Types: 68 typedef basic_streambuf<_CharT, _Traits> __streambuf_type; 69 typedef basic_ios<_CharT, _Traits> __ios_type; 70 typedef basic_ostream<_CharT, _Traits> __ostream_type; 71 typedef num_put<_CharT, ostreambuf_iterator<_CharT, _Traits> > 72 __num_put_type; 73 typedef ctype<_CharT> __ctype_type; 74 75 // [27.6.2.2] constructor/destructor 76 /** 77 * @brief Base constructor. 78 * 79 * This ctor is almost never called by the user directly, rather from 80 * derived classes' initialization lists, which pass a pointer to 81 * their own stream buffer. 82 */ 83 explicit 84 basic_ostream(__streambuf_type* __sb) 85 { this->init(__sb); } 86 87 /** 88 * @brief Base destructor. 89 * 90 * This does very little apart from providing a virtual base dtor. 91 */ 92 virtual 93 ~basic_ostream() { } 94 95 // [27.6.2.3] prefix/suffix 96 class sentry; 97 friend class sentry; 98 99 // [27.6.2.5] formatted output 100 // [27.6.2.5.3] basic_ostream::operator<< 101 //@{ 102 /** 103 * @brief Interface for manipulators. 104 * 105 * Manipulators such as @c std::endl and @c std::hex use these 106 * functions in constructs like "std::cout << std::endl". For more 107 * information, see the iomanip header. 108 */ 109 __ostream_type& 110 operator<<(__ostream_type& (*__pf)(__ostream_type&)) 111 { 112 // _GLIBCXX_RESOLVE_LIB_DEFECTS 113 // DR 60. What is a formatted input function? 114 // The inserters for manipulators are *not* formatted output functions. 115 return __pf(*this); 116 } 117 118 __ostream_type& 119 operator<<(__ios_type& (*__pf)(__ios_type&)) 120 { 121 // _GLIBCXX_RESOLVE_LIB_DEFECTS 122 // DR 60. What is a formatted input function? 123 // The inserters for manipulators are *not* formatted output functions. 124 __pf(*this); 125 return *this; 126 } 127 128 __ostream_type& 129 operator<<(ios_base& (*__pf) (ios_base&)) 130 { 131 // _GLIBCXX_RESOLVE_LIB_DEFECTS 132 // DR 60. What is a formatted input function? 133 // The inserters for manipulators are *not* formatted output functions. 134 __pf(*this); 135 return *this; 136 } 137 //@} 138 139 // [27.6.2.5.2] arithmetic inserters 140 /** 141 * @name Arithmetic Inserters 142 * 143 * All the @c operator<< functions (aka <em>formatted output 144 * functions</em>) have some common behavior. Each starts by 145 * constructing a temporary object of type std::basic_ostream::sentry. 146 * This can have several effects, concluding with the setting of a 147 * status flag; see the sentry documentation for more. 148 * 149 * If the sentry status is good, the function tries to generate 150 * whatever data is appropriate for the type of the argument. 151 * 152 * If an exception is thrown during insertion, ios_base::badbit 153 * will be turned on in the stream's error state without causing an 154 * ios_base::failure to be thrown. The original exception will then 155 * be rethrown. 156 */ 157 //@{ 158 /** 159 * @brief Basic arithmetic inserters 160 * @param A variable of builtin type. 161 * @return @c *this if successful 162 * 163 * These functions use the stream's current locale (specifically, the 164 * @c num_get facet) to perform numeric formatting. 165 */ 166 __ostream_type& 167 operator<<(long __n) 168 { return _M_insert(__n); } 169 170 __ostream_type& 171 operator<<(unsigned long __n) 172 { return _M_insert(__n); } 173 174 __ostream_type& 175 operator<<(bool __n) 176 { return _M_insert(__n); } 177 178 __ostream_type& 179 operator<<(short __n); 180 181 __ostream_type& 182 operator<<(unsigned short __n) 183 { 184 // _GLIBCXX_RESOLVE_LIB_DEFECTS 185 // 117. basic_ostream uses nonexistent num_put member functions. 186 return _M_insert(static_cast<unsigned long>(__n)); 187 } 188 189 __ostream_type& 190 operator<<(int __n); 191 192 __ostream_type& 193 operator<<(unsigned int __n) 194 { 195 // _GLIBCXX_RESOLVE_LIB_DEFECTS 196 // 117. basic_ostream uses nonexistent num_put member functions. 197 return _M_insert(static_cast<unsigned long>(__n)); 198 } 199 200 #ifdef _GLIBCXX_USE_LONG_LONG 201 __ostream_type& 202 operator<<(long long __n) 203 { return _M_insert(__n); } 204 205 __ostream_type& 206 operator<<(unsigned long long __n) 207 { return _M_insert(__n); } 208 #endif 209 210 __ostream_type& 211 operator<<(double __f) 212 { return _M_insert(__f); } 213 214 __ostream_type& 215 operator<<(float __f) 216 { 217 // _GLIBCXX_RESOLVE_LIB_DEFECTS 218 // 117. basic_ostream uses nonexistent num_put member functions. 219 return _M_insert(static_cast<double>(__f)); 220 } 221 222 __ostream_type& 223 operator<<(long double __f) 224 { return _M_insert(__f); } 225 226 __ostream_type& 227 operator<<(const void* __p) 228 { return _M_insert(__p); } 229 230 /** 231 * @brief Extracting from another streambuf. 232 * @param sb A pointer to a streambuf 233 * 234 * This function behaves like one of the basic arithmetic extractors, 235 * in that it also constructs a sentry object and has the same error 236 * handling behavior. 237 * 238 * If @a sb is NULL, the stream will set failbit in its error state. 239 * 240 * Characters are extracted from @a sb and inserted into @c *this 241 * until one of the following occurs: 242 * 243 * - the input stream reaches end-of-file, 244 * - insertion into the output sequence fails (in this case, the 245 * character that would have been inserted is not extracted), or 246 * - an exception occurs while getting a character from @a sb, which 247 * sets failbit in the error state 248 * 249 * If the function inserts no characters, failbit is set. 250 */ 251 __ostream_type& 252 operator<<(__streambuf_type* __sb); 253 //@} 254 255 // [27.6.2.6] unformatted output functions 256 /** 257 * @name Unformatted Output Functions 258 * 259 * All the unformatted output functions have some common behavior. 260 * Each starts by constructing a temporary object of type 261 * std::basic_ostream::sentry. This has several effects, concluding 262 * with the setting of a status flag; see the sentry documentation 263 * for more. 264 * 265 * If the sentry status is good, the function tries to generate 266 * whatever data is appropriate for the type of the argument. 267 * 268 * If an exception is thrown during insertion, ios_base::badbit 269 * will be turned on in the stream's error state. If badbit is on in 270 * the stream's exceptions mask, the exception will be rethrown 271 * without completing its actions. 272 */ 273 //@{ 274 /** 275 * @brief Simple insertion. 276 * @param c The character to insert. 277 * @return *this 278 * 279 * Tries to insert @a c. 280 * 281 * @note This function is not overloaded on signed char and 282 * unsigned char. 283 */ 284 __ostream_type& 285 put(char_type __c); 286 287 // Core write functionality, without sentry. 288 void 289 _M_write(const char_type* __s, streamsize __n) 290 { 291 const streamsize __put = this->rdbuf()->sputn(__s, __n); 292 if (__put != __n) 293 this->setstate(ios_base::badbit); 294 } 295 296 /** 297 * @brief Character string insertion. 298 * @param s The array to insert. 299 * @param n Maximum number of characters to insert. 300 * @return *this 301 * 302 * Characters are copied from @a s and inserted into the stream until 303 * one of the following happens: 304 * 305 * - @a n characters are inserted 306 * - inserting into the output sequence fails (in this case, badbit 307 * will be set in the stream's error state) 308 * 309 * @note This function is not overloaded on signed char and 310 * unsigned char. 311 */ 312 __ostream_type& 313 write(const char_type* __s, streamsize __n); 314 //@} 315 316 /** 317 * @brief Synchronizing the stream buffer. 318 * @return *this 319 * 320 * If @c rdbuf() is a null pointer, changes nothing. 321 * 322 * Otherwise, calls @c rdbuf()->pubsync(), and if that returns -1, 323 * sets badbit. 324 */ 325 __ostream_type& 326 flush(); 327 328 // [27.6.2.4] seek members 329 /** 330 * @brief Getting the current write position. 331 * @return A file position object. 332 * 333 * If @c fail() is not false, returns @c pos_type(-1) to indicate 334 * failure. Otherwise returns @c rdbuf()->pubseekoff(0,cur,out). 335 */ 336 pos_type 337 tellp(); 338 339 /** 340 * @brief Changing the current write position. 341 * @param pos A file position object. 342 * @return *this 343 * 344 * If @c fail() is not true, calls @c rdbuf()->pubseekpos(pos). If 345 * that function fails, sets failbit. 346 */ 347 __ostream_type& 348 seekp(pos_type); 349 350 /** 351 * @brief Changing the current write position. 352 * @param off A file offset object. 353 * @param dir The direction in which to seek. 354 * @return *this 355 * 356 * If @c fail() is not true, calls @c rdbuf()->pubseekoff(off,dir). 357 * If that function fails, sets failbit. 358 */ 359 __ostream_type& 360 seekp(off_type, ios_base::seekdir); 361 362 protected: 363 basic_ostream() 364 { this->init(0); } 365 366 template<typename _ValueT> 367 __ostream_type& 368 _M_insert(_ValueT __v); 369 }; 370 371 /** 372 * @brief Performs setup work for output streams. 373 * 374 * Objects of this class are created before all of the standard 375 * inserters are run. It is responsible for <em>exception-safe prefix and 376 * suffix operations</em>. 377 */ 378 template <typename _CharT, typename _Traits> 379 class basic_ostream<_CharT, _Traits>::sentry 380 { 381 // Data Members. 382 bool _M_ok; 383 basic_ostream<_CharT, _Traits>& _M_os; 384 385 public: 386 /** 387 * @brief The constructor performs preparatory work. 388 * @param os The output stream to guard. 389 * 390 * If the stream state is good (@a os.good() is true), then if the 391 * stream is tied to another output stream, @c is.tie()->flush() 392 * is called to synchronize the output sequences. 393 * 394 * If the stream state is still good, then the sentry state becomes 395 * true (@a okay). 396 */ 397 explicit 398 sentry(basic_ostream<_CharT, _Traits>& __os); 399 400 /** 401 * @brief Possibly flushes the stream. 402 * 403 * If @c ios_base::unitbuf is set in @c os.flags(), and 404 * @c std::uncaught_exception() is true, the sentry destructor calls 405 * @c flush() on the output stream. 406 */ 407 ~sentry() 408 { 409 // XXX MT 410 if (bool(_M_os.flags() & ios_base::unitbuf) && !uncaught_exception()) 411 { 412 // Can't call flush directly or else will get into recursive lock. 413 if (_M_os.rdbuf() && _M_os.rdbuf()->pubsync() == -1) 414 _M_os.setstate(ios_base::badbit); 415 } 416 } 417 418 /** 419 * @brief Quick status checking. 420 * @return The sentry state. 421 * 422 * For ease of use, sentries may be converted to booleans. The 423 * return value is that of the sentry state (true == okay). 424 */ 425 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 426 explicit 427 #endif 428 operator bool() const 429 { return _M_ok; } 430 }; 431 432 // [27.6.2.5.4] character insertion templates 433 //@{ 434 /** 435 * @brief Character inserters 436 * @param out An output stream. 437 * @param c A character. 438 * @return out 439 * 440 * Behaves like one of the formatted arithmetic inserters described in 441 * std::basic_ostream. After constructing a sentry object with good 442 * status, this function inserts a single character and any required 443 * padding (as determined by [22.2.2.2.2]). @c out.width(0) is then 444 * called. 445 * 446 * If @a c is of type @c char and the character type of the stream is not 447 * @c char, the character is widened before insertion. 448 */ 449 template<typename _CharT, typename _Traits> 450 inline basic_ostream<_CharT, _Traits>& 451 operator<<(basic_ostream<_CharT, _Traits>& __out, _CharT __c) 452 { return __ostream_insert(__out, &__c, 1); } 453 454 template<typename _CharT, typename _Traits> 455 inline basic_ostream<_CharT, _Traits>& 456 operator<<(basic_ostream<_CharT, _Traits>& __out, char __c) 457 { return (__out << __out.widen(__c)); } 458 459 // Specialization 460 template <class _Traits> 461 inline basic_ostream<char, _Traits>& 462 operator<<(basic_ostream<char, _Traits>& __out, char __c) 463 { return __ostream_insert(__out, &__c, 1); } 464 465 // Signed and unsigned 466 template<class _Traits> 467 inline basic_ostream<char, _Traits>& 468 operator<<(basic_ostream<char, _Traits>& __out, signed char __c) 469 { return (__out << static_cast<char>(__c)); } 470 471 template<class _Traits> 472 inline basic_ostream<char, _Traits>& 473 operator<<(basic_ostream<char, _Traits>& __out, unsigned char __c) 474 { return (__out << static_cast<char>(__c)); } 475 //@} 476 477 //@{ 478 /** 479 * @brief String inserters 480 * @param out An output stream. 481 * @param s A character string. 482 * @return out 483 * @pre @a s must be a non-NULL pointer 484 * 485 * Behaves like one of the formatted arithmetic inserters described in 486 * std::basic_ostream. After constructing a sentry object with good 487 * status, this function inserts @c traits::length(s) characters starting 488 * at @a s, widened if necessary, followed by any required padding (as 489 * determined by [22.2.2.2.2]). @c out.width(0) is then called. 490 */ 491 template<typename _CharT, typename _Traits> 492 inline basic_ostream<_CharT, _Traits>& 493 operator<<(basic_ostream<_CharT, _Traits>& __out, const _CharT* __s) 494 { 495 if (!__s) 496 __out.setstate(ios_base::badbit); 497 else 498 __ostream_insert(__out, __s, 499 static_cast<streamsize>(_Traits::length(__s))); 500 return __out; 501 } 502 503 template<typename _CharT, typename _Traits> 504 basic_ostream<_CharT, _Traits> & 505 operator<<(basic_ostream<_CharT, _Traits>& __out, const char* __s); 506 507 // Partial specializations 508 template<class _Traits> 509 inline basic_ostream<char, _Traits>& 510 operator<<(basic_ostream<char, _Traits>& __out, const char* __s) 511 { 512 if (!__s) 513 __out.setstate(ios_base::badbit); 514 else 515 __ostream_insert(__out, __s, 516 static_cast<streamsize>(_Traits::length(__s))); 517 return __out; 518 } 519 520 // Signed and unsigned 521 template<class _Traits> 522 inline basic_ostream<char, _Traits>& 523 operator<<(basic_ostream<char, _Traits>& __out, const signed char* __s) 524 { return (__out << reinterpret_cast<const char*>(__s)); } 525 526 template<class _Traits> 527 inline basic_ostream<char, _Traits> & 528 operator<<(basic_ostream<char, _Traits>& __out, const unsigned char* __s) 529 { return (__out << reinterpret_cast<const char*>(__s)); } 530 //@} 531 532 // [27.6.2.7] standard basic_ostream manipulators 533 /** 534 * @brief Write a newline and flush the stream. 535 * 536 * This manipulator is often mistakenly used when a simple newline is 537 * desired, leading to poor buffering performance. See 538 * http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt11ch25s02.html 539 * for more on this subject. 540 */ 541 template<typename _CharT, typename _Traits> 542 inline basic_ostream<_CharT, _Traits>& 543 endl(basic_ostream<_CharT, _Traits>& __os) 544 { return flush(__os.put(__os.widen('\n'))); } 545 546 /** 547 * @brief Write a null character into the output sequence. 548 * 549 * <em>Null character</em> is @c CharT() by definition. For CharT of @c char, 550 * this correctly writes the ASCII @c NUL character string terminator. 551 */ 552 template<typename _CharT, typename _Traits> 553 inline basic_ostream<_CharT, _Traits>& 554 ends(basic_ostream<_CharT, _Traits>& __os) 555 { return __os.put(_CharT()); } 556 557 /** 558 * @brief Flushes the output stream. 559 * 560 * This manipulator simply calls the stream's @c flush() member function. 561 */ 562 template<typename _CharT, typename _Traits> 563 inline basic_ostream<_CharT, _Traits>& 564 flush(basic_ostream<_CharT, _Traits>& __os) 565 { return __os.flush(); } 566 567 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 568 // [27.7.2.9] Rvalue stream insertion 569 /** 570 * @brief Generic inserter for rvalue stream 571 * @param os An input stream. 572 * @param x A reference to the object being inserted. 573 * @return os 574 * 575 * This is just a forwarding function to allow insertion to 576 * rvalue streams since they won't bind to the inserter functions 577 * that take an lvalue reference. 578 */ 579 template<typename _CharT, typename _Traits, typename _Tp> 580 inline basic_ostream<_CharT, _Traits>& 581 operator<<(basic_ostream<_CharT, _Traits>&& __os, const _Tp& __x) 582 { return (__os << __x); } 583 #endif // __GXX_EXPERIMENTAL_CXX0X__ 584 585 _GLIBCXX_END_NAMESPACE_VERSION 586 } // namespace 587 588 #include <bits/ostream.tcc> 589 590 #endif /* _GLIBCXX_OSTREAM */ 591
