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 /** 48 * @brief Template class basic_ostream. 49 * @ingroup io 50 * 51 * This is the base class for all output streams. It provides text 52 * formatting of all builtin types, and communicates with any class 53 * derived from basic_streambuf to do the actual output. 54 */ 55 template<typename _CharT, typename _Traits> 56 class basic_ostream : virtual public basic_ios<_CharT, _Traits> 57 { 58 public: 59 // Types (inherited from basic_ios): 60 typedef _CharT char_type; 61 typedef typename _Traits::int_type int_type; 62 typedef typename _Traits::pos_type pos_type; 63 typedef typename _Traits::off_type off_type; 64 typedef _Traits traits_type; 65 66 // Non-standard Types: 67 typedef basic_streambuf<_CharT, _Traits> __streambuf_type; 68 typedef basic_ios<_CharT, _Traits> __ios_type; 69 typedef basic_ostream<_CharT, _Traits> __ostream_type; 70 typedef num_put<_CharT, ostreambuf_iterator<_CharT, _Traits> > 71 __num_put_type; 72 typedef ctype<_CharT> __ctype_type; 73 74 /** 75 * @brief Base constructor. 76 * 77 * This ctor is almost never called by the user directly, rather from 78 * derived classes' initialization lists, which pass a pointer to 79 * their own stream buffer. 80 */ 81 explicit 82 basic_ostream(__streambuf_type* __sb) 83 { this->init(__sb); } 84 85 /** 86 * @brief Base destructor. 87 * 88 * This does very little apart from providing a virtual base dtor. 89 */ 90 virtual 91 ~basic_ostream() { } 92 93 /// Safe prefix/suffix operations. 94 class sentry; 95 friend class sentry; 96 97 //@{ 98 /** 99 * @brief Interface for manipulators. 100 * 101 * Manipulators such as @c std::endl and @c std::hex use these 102 * functions in constructs like "std::cout << std::endl". For more 103 * information, see the iomanip header. 104 */ 105 __ostream_type& 106 operator<<(__ostream_type& (*__pf)(__ostream_type&)) 107 { 108 // _GLIBCXX_RESOLVE_LIB_DEFECTS 109 // DR 60. What is a formatted input function? 110 // The inserters for manipulators are *not* formatted output functions. 111 return __pf(*this); 112 } 113 114 __ostream_type& 115 operator<<(__ios_type& (*__pf)(__ios_type&)) 116 { 117 // _GLIBCXX_RESOLVE_LIB_DEFECTS 118 // DR 60. What is a formatted input function? 119 // The inserters for manipulators are *not* formatted output functions. 120 __pf(*this); 121 return *this; 122 } 123 124 __ostream_type& 125 operator<<(ios_base& (*__pf) (ios_base&)) 126 { 127 // _GLIBCXX_RESOLVE_LIB_DEFECTS 128 // DR 60. What is a formatted input function? 129 // The inserters for manipulators are *not* formatted output functions. 130 __pf(*this); 131 return *this; 132 } 133 //@} 134 135 //@{ 136 /** 137 * @name Inserters 138 * 139 * All the @c operator<< functions (aka <em>formatted output 140 * functions</em>) have some common behavior. Each starts by 141 * constructing a temporary object of type std::basic_ostream::sentry. 142 * This can have several effects, concluding with the setting of a 143 * status flag; see the sentry documentation for more. 144 * 145 * If the sentry status is good, the function tries to generate 146 * whatever data is appropriate for the type of the argument. 147 * 148 * If an exception is thrown during insertion, ios_base::badbit 149 * will be turned on in the stream's error state without causing an 150 * ios_base::failure to be thrown. The original exception will then 151 * be rethrown. 152 */ 153 154 //@{ 155 /** 156 * @brief Integer arithmetic inserters 157 * @param __n A variable of builtin integral type. 158 * @return @c *this if successful 159 * 160 * These functions use the stream's current locale (specifically, the 161 * @c num_get facet) to perform numeric formatting. 162 */ 163 __ostream_type& 164 operator<<(long __n) 165 { return _M_insert(__n); } 166 167 __ostream_type& 168 operator<<(unsigned long __n) 169 { return _M_insert(__n); } 170 171 __ostream_type& 172 operator<<(bool __n) 173 { return _M_insert(__n); } 174 175 __ostream_type& 176 operator<<(short __n); 177 178 __ostream_type& 179 operator<<(unsigned short __n) 180 { 181 // _GLIBCXX_RESOLVE_LIB_DEFECTS 182 // 117. basic_ostream uses nonexistent num_put member functions. 183 return _M_insert(static_cast<unsigned long>(__n)); 184 } 185 186 __ostream_type& 187 operator<<(int __n); 188 189 __ostream_type& 190 operator<<(unsigned int __n) 191 { 192 // _GLIBCXX_RESOLVE_LIB_DEFECTS 193 // 117. basic_ostream uses nonexistent num_put member functions. 194 return _M_insert(static_cast<unsigned long>(__n)); 195 } 196 197 #ifdef _GLIBCXX_USE_LONG_LONG 198 __ostream_type& 199 operator<<(long long __n) 200 { return _M_insert(__n); } 201 202 __ostream_type& 203 operator<<(unsigned long long __n) 204 { return _M_insert(__n); } 205 #endif 206 //@} 207 208 //@{ 209 /** 210 * @brief Floating point arithmetic inserters 211 * @param __f A variable of builtin floating point type. 212 * @return @c *this if successful 213 * 214 * These functions use the stream's current locale (specifically, the 215 * @c num_get facet) to perform numeric formatting. 216 */ 217 __ostream_type& 218 operator<<(double __f) 219 { return _M_insert(__f); } 220 221 __ostream_type& 222 operator<<(float __f) 223 { 224 // _GLIBCXX_RESOLVE_LIB_DEFECTS 225 // 117. basic_ostream uses nonexistent num_put member functions. 226 return _M_insert(static_cast<double>(__f)); 227 } 228 229 __ostream_type& 230 operator<<(long double __f) 231 { return _M_insert(__f); } 232 //@} 233 234 /** 235 * @brief Pointer arithmetic inserters 236 * @param __p A variable of pointer type. 237 * @return @c *this if successful 238 * 239 * These functions use the stream's current locale (specifically, the 240 * @c num_get facet) to perform numeric formatting. 241 */ 242 __ostream_type& 243 operator<<(const void* __p) 244 { return _M_insert(__p); } 245 246 /** 247 * @brief Extracting from another streambuf. 248 * @param __sb A pointer to a streambuf 249 * 250 * This function behaves like one of the basic arithmetic extractors, 251 * in that it also constructs a sentry object and has the same error 252 * handling behavior. 253 * 254 * If @p __sb is NULL, the stream will set failbit in its error state. 255 * 256 * Characters are extracted from @p __sb and inserted into @c *this 257 * until one of the following occurs: 258 * 259 * - the input stream reaches end-of-file, 260 * - insertion into the output sequence fails (in this case, the 261 * character that would have been inserted is not extracted), or 262 * - an exception occurs while getting a character from @p __sb, which 263 * sets failbit in the error state 264 * 265 * If the function inserts no characters, failbit is set. 266 */ 267 __ostream_type& 268 operator<<(__streambuf_type* __sb); 269 //@} 270 271 //@{ 272 /** 273 * @name Unformatted Output Functions 274 * 275 * All the unformatted output functions have some common behavior. 276 * Each starts by constructing a temporary object of type 277 * std::basic_ostream::sentry. This has several effects, concluding 278 * with the setting of a status flag; see the sentry documentation 279 * for more. 280 * 281 * If the sentry status is good, the function tries to generate 282 * whatever data is appropriate for the type of the argument. 283 * 284 * If an exception is thrown during insertion, ios_base::badbit 285 * will be turned on in the stream's error state. If badbit is on in 286 * the stream's exceptions mask, the exception will be rethrown 287 * without completing its actions. 288 */ 289 290 /** 291 * @brief Simple insertion. 292 * @param __c The character to insert. 293 * @return *this 294 * 295 * Tries to insert @p __c. 296 * 297 * @note This function is not overloaded on signed char and 298 * unsigned char. 299 */ 300 __ostream_type& 301 put(char_type __c); 302 303 /** 304 * @brief Core write functionality, without sentry. 305 * @param __s The array to insert. 306 * @param __n Maximum number of characters to insert. 307 */ 308 void 309 _M_write(const char_type* __s, streamsize __n) 310 { 311 const streamsize __put = this->rdbuf()->sputn(__s, __n); 312 if (__put != __n) 313 this->setstate(ios_base::badbit); 314 } 315 316 /** 317 * @brief Character string insertion. 318 * @param __s The array to insert. 319 * @param __n Maximum number of characters to insert. 320 * @return *this 321 * 322 * Characters are copied from @p __s and inserted into the stream until 323 * one of the following happens: 324 * 325 * - @p __n characters are inserted 326 * - inserting into the output sequence fails (in this case, badbit 327 * will be set in the stream's error state) 328 * 329 * @note This function is not overloaded on signed char and 330 * unsigned char. 331 */ 332 __ostream_type& 333 write(const char_type* __s, streamsize __n); 334 //@} 335 336 /** 337 * @brief Synchronizing the stream buffer. 338 * @return *this 339 * 340 * If @c rdbuf() is a null pointer, changes nothing. 341 * 342 * Otherwise, calls @c rdbuf()->pubsync(), and if that returns -1, 343 * sets badbit. 344 */ 345 __ostream_type& 346 flush(); 347 348 /** 349 * @brief Getting the current write position. 350 * @return A file position object. 351 * 352 * If @c fail() is not false, returns @c pos_type(-1) to indicate 353 * failure. Otherwise returns @c rdbuf()->pubseekoff(0,cur,out). 354 */ 355 pos_type 356 tellp(); 357 358 /** 359 * @brief Changing the current write position. 360 * @param __pos A file position object. 361 * @return *this 362 * 363 * If @c fail() is not true, calls @c rdbuf()->pubseekpos(pos). If 364 * that function fails, sets failbit. 365 */ 366 __ostream_type& 367 seekp(pos_type); 368 369 /** 370 * @brief Changing the current write position. 371 * @param __off A file offset object. 372 * @param __dir The direction in which to seek. 373 * @return *this 374 * 375 * If @c fail() is not true, calls @c rdbuf()->pubseekoff(off,dir). 376 * If that function fails, sets failbit. 377 */ 378 __ostream_type& 379 seekp(off_type, ios_base::seekdir); 380 381 protected: 382 basic_ostream() 383 { this->init(0); } 384 385 template<typename _ValueT> 386 __ostream_type& 387 _M_insert(_ValueT __v); 388 }; 389 390 /** 391 * @brief Performs setup work for output streams. 392 * 393 * Objects of this class are created before all of the standard 394 * inserters are run. It is responsible for <em>exception-safe prefix and 395 * suffix operations</em>. 396 */ 397 template <typename _CharT, typename _Traits> 398 class basic_ostream<_CharT, _Traits>::sentry 399 { 400 // Data Members. 401 bool _M_ok; 402 basic_ostream<_CharT, _Traits>& _M_os; 403 404 public: 405 /** 406 * @brief The constructor performs preparatory work. 407 * @param __os The output stream to guard. 408 * 409 * If the stream state is good (@a __os.good() is true), then if the 410 * stream is tied to another output stream, @c is.tie()->flush() 411 * is called to synchronize the output sequences. 412 * 413 * If the stream state is still good, then the sentry state becomes 414 * true (@a okay). 415 */ 416 explicit 417 sentry(basic_ostream<_CharT, _Traits>& __os); 418 419 /** 420 * @brief Possibly flushes the stream. 421 * 422 * If @c ios_base::unitbuf is set in @c os.flags(), and 423 * @c std::uncaught_exception() is true, the sentry destructor calls 424 * @c flush() on the output stream. 425 */ 426 ~sentry() 427 { 428 // XXX MT 429 if (bool(_M_os.flags() & ios_base::unitbuf) && !uncaught_exception()) 430 { 431 // Can't call flush directly or else will get into recursive lock. 432 if (_M_os.rdbuf() && _M_os.rdbuf()->pubsync() == -1) 433 _M_os.setstate(ios_base::badbit); 434 } 435 } 436 437 /** 438 * @brief Quick status checking. 439 * @return The sentry state. 440 * 441 * For ease of use, sentries may be converted to booleans. The 442 * return value is that of the sentry state (true == okay). 443 */ 444 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 445 explicit 446 #endif 447 operator bool() const 448 { return _M_ok; } 449 }; 450 451 //@{ 452 /** 453 * @brief Character inserters 454 * @param __out An output stream. 455 * @param __c A character. 456 * @return out 457 * 458 * Behaves like one of the formatted arithmetic inserters described in 459 * std::basic_ostream. After constructing a sentry object with good 460 * status, this function inserts a single character and any required 461 * padding (as determined by [22.2.2.2.2]). @c __out.width(0) is then 462 * called. 463 * 464 * If @p __c is of type @c char and the character type of the stream is not 465 * @c char, the character is widened before insertion. 466 */ 467 template<typename _CharT, typename _Traits> 468 inline basic_ostream<_CharT, _Traits>& 469 operator<<(basic_ostream<_CharT, _Traits>& __out, _CharT __c) 470 { return __ostream_insert(__out, &__c, 1); } 471 472 template<typename _CharT, typename _Traits> 473 inline basic_ostream<_CharT, _Traits>& 474 operator<<(basic_ostream<_CharT, _Traits>& __out, char __c) 475 { return (__out << __out.widen(__c)); } 476 477 // Specialization 478 template <class _Traits> 479 inline basic_ostream<char, _Traits>& 480 operator<<(basic_ostream<char, _Traits>& __out, char __c) 481 { return __ostream_insert(__out, &__c, 1); } 482 483 // Signed and unsigned 484 template<class _Traits> 485 inline basic_ostream<char, _Traits>& 486 operator<<(basic_ostream<char, _Traits>& __out, signed char __c) 487 { return (__out << static_cast<char>(__c)); } 488 489 template<class _Traits> 490 inline basic_ostream<char, _Traits>& 491 operator<<(basic_ostream<char, _Traits>& __out, unsigned char __c) 492 { return (__out << static_cast<char>(__c)); } 493 //@} 494 495 //@{ 496 /** 497 * @brief String inserters 498 * @param __out An output stream. 499 * @param __s A character string. 500 * @return out 501 * @pre @p __s must be a non-NULL pointer 502 * 503 * Behaves like one of the formatted arithmetic inserters described in 504 * std::basic_ostream. After constructing a sentry object with good 505 * status, this function inserts @c traits::length(__s) characters starting 506 * at @p __s, widened if necessary, followed by any required padding (as 507 * determined by [22.2.2.2.2]). @c __out.width(0) is then called. 508 */ 509 template<typename _CharT, typename _Traits> 510 inline basic_ostream<_CharT, _Traits>& 511 operator<<(basic_ostream<_CharT, _Traits>& __out, const _CharT* __s) 512 { 513 if (!__s) 514 __out.setstate(ios_base::badbit); 515 else 516 __ostream_insert(__out, __s, 517 static_cast<streamsize>(_Traits::length(__s))); 518 return __out; 519 } 520 521 template<typename _CharT, typename _Traits> 522 basic_ostream<_CharT, _Traits> & 523 operator<<(basic_ostream<_CharT, _Traits>& __out, const char* __s); 524 525 // Partial specializations 526 template<class _Traits> 527 inline basic_ostream<char, _Traits>& 528 operator<<(basic_ostream<char, _Traits>& __out, const char* __s) 529 { 530 if (!__s) 531 __out.setstate(ios_base::badbit); 532 else 533 __ostream_insert(__out, __s, 534 static_cast<streamsize>(_Traits::length(__s))); 535 return __out; 536 } 537 538 // Signed and unsigned 539 template<class _Traits> 540 inline basic_ostream<char, _Traits>& 541 operator<<(basic_ostream<char, _Traits>& __out, const signed char* __s) 542 { return (__out << reinterpret_cast<const char*>(__s)); } 543 544 template<class _Traits> 545 inline basic_ostream<char, _Traits> & 546 operator<<(basic_ostream<char, _Traits>& __out, const unsigned char* __s) 547 { return (__out << reinterpret_cast<const char*>(__s)); } 548 //@} 549 550 // Standard basic_ostream manipulators 551 552 /** 553 * @brief Write a newline and flush the stream. 554 * 555 * This manipulator is often mistakenly used when a simple newline is 556 * desired, leading to poor buffering performance. See 557 * http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt11ch25s02.html 558 * for more on this subject. 559 */ 560 template<typename _CharT, typename _Traits> 561 inline basic_ostream<_CharT, _Traits>& 562 endl(basic_ostream<_CharT, _Traits>& __os) 563 { return flush(__os.put(__os.widen('\n'))); } 564 565 /** 566 * @brief Write a null character into the output sequence. 567 * 568 * <em>Null character</em> is @c CharT() by definition. For CharT 569 * of @c char, this correctly writes the ASCII @c NUL character 570 * string terminator. 571 */ 572 template<typename _CharT, typename _Traits> 573 inline basic_ostream<_CharT, _Traits>& 574 ends(basic_ostream<_CharT, _Traits>& __os) 575 { return __os.put(_CharT()); } 576 577 /** 578 * @brief Flushes the output stream. 579 * 580 * This manipulator simply calls the stream's @c flush() member function. 581 */ 582 template<typename _CharT, typename _Traits> 583 inline basic_ostream<_CharT, _Traits>& 584 flush(basic_ostream<_CharT, _Traits>& __os) 585 { return __os.flush(); } 586 587 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 588 /** 589 * @brief Generic inserter for rvalue stream 590 * @param __os An input stream. 591 * @param __x A reference to the object being inserted. 592 * @return os 593 * 594 * This is just a forwarding function to allow insertion to 595 * rvalue streams since they won't bind to the inserter functions 596 * that take an lvalue reference. 597 */ 598 template<typename _CharT, typename _Traits, typename _Tp> 599 inline basic_ostream<_CharT, _Traits>& 600 operator<<(basic_ostream<_CharT, _Traits>&& __os, const _Tp& __x) 601 { return (__os << __x); } 602 #endif // __GXX_EXPERIMENTAL_CXX0X__ 603 604 _GLIBCXX_END_NAMESPACE_VERSION 605 } // namespace std 606 607 #include <bits/ostream.tcc> 608 609 #endif /* _GLIBCXX_OSTREAM */ 610
