1 // Output streams -*- C++ -*- 2 3 // Copyright (C) 1997-2014 Free Software Foundation, Inc. 4 // 5 // This file is part of the GNU ISO C++ Library. This library is free 6 // software; you can redistribute it and/or modify it under the 7 // terms of the GNU General Public License as published by the 8 // Free Software Foundation; either version 3, or (at your option) 9 // any later version. 10 11 // This library is distributed in the hope that it will be useful, 12 // but WITHOUT ANY WARRANTY; without even the implied warranty of 13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 // GNU General Public License for more details. 15 16 // Under Section 7 of GPL version 3, you are granted additional 17 // permissions described in the GCC Runtime Library Exception, version 18 // 3.1, as published by the Free Software Foundation. 19 20 // You should have received a copy of the GNU General Public License and 21 // a copy of the GCC Runtime Library Exception along with this program; 22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 23 // <http://www.gnu.org/licenses/>. 24 25 /** @file include/ostream 26 * This is a Standard C++ Library header. 27 */ 28 29 // 30 // ISO C++ 14882: 27.6.2 Output streams 31 // 32 33 #ifndef _GLIBCXX_OSTREAM 34 #define _GLIBCXX_OSTREAM 1 35 36 #pragma GCC system_header 37 38 #include <ios> 39 #include <bits/ostream_insert.h> 40 41 namespace std _GLIBCXX_VISIBILITY(default) 42 { 43 _GLIBCXX_BEGIN_NAMESPACE_VERSION 44 45 /** 46 * @brief Template class basic_ostream. 47 * @ingroup io 48 * 49 * @tparam _CharT Type of character stream. 50 * @tparam _Traits Traits for character type, defaults to 51 * char_traits<_CharT>. 52 * 53 * This is the base class for all output streams. It provides text 54 * formatting of all builtin types, and communicates with any class 55 * derived from basic_streambuf to do the actual output. 56 */ 57 template<typename _CharT, typename _Traits> 58 class basic_ostream : virtual public basic_ios<_CharT, _Traits> 59 { 60 public: 61 // Types (inherited from basic_ios): 62 typedef _CharT char_type; 63 typedef typename _Traits::int_type int_type; 64 typedef typename _Traits::pos_type pos_type; 65 typedef typename _Traits::off_type off_type; 66 typedef _Traits traits_type; 67 68 // Non-standard Types: 69 typedef basic_streambuf<_CharT, _Traits> __streambuf_type; 70 typedef basic_ios<_CharT, _Traits> __ios_type; 71 typedef basic_ostream<_CharT, _Traits> __ostream_type; 72 typedef num_put<_CharT, ostreambuf_iterator<_CharT, _Traits> > 73 __num_put_type; 74 typedef ctype<_CharT> __ctype_type; 75 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 /// Safe prefix/suffix operations. 96 class sentry; 97 friend class sentry; 98 99 //@{ 100 /** 101 * @brief Interface for manipulators. 102 * 103 * Manipulators such as @c std::endl and @c std::hex use these 104 * functions in constructs like "std::cout << std::endl". For more 105 * information, see the iomanip header. 106 */ 107 __ostream_type& 108 operator<<(__ostream_type& (*__pf)(__ostream_type&)) 109 { 110 // _GLIBCXX_RESOLVE_LIB_DEFECTS 111 // DR 60. What is a formatted input function? 112 // The inserters for manipulators are *not* formatted output functions. 113 return __pf(*this); 114 } 115 116 __ostream_type& 117 operator<<(__ios_type& (*__pf)(__ios_type&)) 118 { 119 // _GLIBCXX_RESOLVE_LIB_DEFECTS 120 // DR 60. What is a formatted input function? 121 // The inserters for manipulators are *not* formatted output functions. 122 __pf(*this); 123 return *this; 124 } 125 126 __ostream_type& 127 operator<<(ios_base& (*__pf) (ios_base&)) 128 { 129 // _GLIBCXX_RESOLVE_LIB_DEFECTS 130 // DR 60. What is a formatted input function? 131 // The inserters for manipulators are *not* formatted output functions. 132 __pf(*this); 133 return *this; 134 } 135 //@} 136 137 //@{ 138 /** 139 * @name Inserters 140 * 141 * All the @c operator<< functions (aka <em>formatted output 142 * functions</em>) have some common behavior. Each starts by 143 * constructing a temporary object of type std::basic_ostream::sentry. 144 * This can have several effects, concluding with the setting of a 145 * status flag; see the sentry documentation for more. 146 * 147 * If the sentry status is good, the function tries to generate 148 * whatever data is appropriate for the type of the argument. 149 * 150 * If an exception is thrown during insertion, ios_base::badbit 151 * will be turned on in the stream's error state without causing an 152 * ios_base::failure to be thrown. The original exception will then 153 * be rethrown. 154 */ 155 156 //@{ 157 /** 158 * @brief Integer arithmetic inserters 159 * @param __n A variable of builtin integral type. 160 * @return @c *this if successful 161 * 162 * These functions use the stream's current locale (specifically, the 163 * @c num_get facet) to perform numeric formatting. 164 */ 165 __ostream_type& 166 operator<<(long __n) 167 { return _M_insert(__n); } 168 169 __ostream_type& 170 operator<<(unsigned long __n) 171 { return _M_insert(__n); } 172 173 __ostream_type& 174 operator<<(bool __n) 175 { return _M_insert(__n); } 176 177 __ostream_type& 178 operator<<(short __n); 179 180 __ostream_type& 181 operator<<(unsigned short __n) 182 { 183 // _GLIBCXX_RESOLVE_LIB_DEFECTS 184 // 117. basic_ostream uses nonexistent num_put member functions. 185 return _M_insert(static_cast<unsigned long>(__n)); 186 } 187 188 __ostream_type& 189 operator<<(int __n); 190 191 __ostream_type& 192 operator<<(unsigned int __n) 193 { 194 // _GLIBCXX_RESOLVE_LIB_DEFECTS 195 // 117. basic_ostream uses nonexistent num_put member functions. 196 return _M_insert(static_cast<unsigned long>(__n)); 197 } 198 199 #ifdef _GLIBCXX_USE_LONG_LONG 200 __ostream_type& 201 operator<<(long long __n) 202 { return _M_insert(__n); } 203 204 __ostream_type& 205 operator<<(unsigned long long __n) 206 { return _M_insert(__n); } 207 #endif 208 //@} 209 210 //@{ 211 /** 212 * @brief Floating point arithmetic inserters 213 * @param __f A variable of builtin floating point type. 214 * @return @c *this if successful 215 * 216 * These functions use the stream's current locale (specifically, the 217 * @c num_get facet) to perform numeric formatting. 218 */ 219 __ostream_type& 220 operator<<(double __f) 221 { return _M_insert(__f); } 222 223 __ostream_type& 224 operator<<(float __f) 225 { 226 // _GLIBCXX_RESOLVE_LIB_DEFECTS 227 // 117. basic_ostream uses nonexistent num_put member functions. 228 return _M_insert(static_cast<double>(__f)); 229 } 230 231 __ostream_type& 232 operator<<(long double __f) 233 { return _M_insert(__f); } 234 //@} 235 236 /** 237 * @brief Pointer arithmetic inserters 238 * @param __p A variable of pointer type. 239 * @return @c *this if successful 240 * 241 * These functions use the stream's current locale (specifically, the 242 * @c num_get facet) to perform numeric formatting. 243 */ 244 __ostream_type& 245 operator<<(const void* __p) 246 { return _M_insert(__p); } 247 248 /** 249 * @brief Extracting from another streambuf. 250 * @param __sb A pointer to a streambuf 251 * 252 * This function behaves like one of the basic arithmetic extractors, 253 * in that it also constructs a sentry object and has the same error 254 * handling behavior. 255 * 256 * If @p __sb is NULL, the stream will set failbit in its error state. 257 * 258 * Characters are extracted from @p __sb and inserted into @c *this 259 * until one of the following occurs: 260 * 261 * - the input stream reaches end-of-file, 262 * - insertion into the output sequence fails (in this case, the 263 * character that would have been inserted is not extracted), or 264 * - an exception occurs while getting a character from @p __sb, which 265 * sets failbit in the error state 266 * 267 * If the function inserts no characters, failbit is set. 268 */ 269 __ostream_type& 270 operator<<(__streambuf_type* __sb); 271 //@} 272 273 //@{ 274 /** 275 * @name Unformatted Output Functions 276 * 277 * All the unformatted output functions have some common behavior. 278 * Each starts by constructing a temporary object of type 279 * std::basic_ostream::sentry. This has several effects, concluding 280 * with the setting of a status flag; see the sentry documentation 281 * for more. 282 * 283 * If the sentry status is good, the function tries to generate 284 * whatever data is appropriate for the type of the argument. 285 * 286 * If an exception is thrown during insertion, ios_base::badbit 287 * will be turned on in the stream's error state. If badbit is on in 288 * the stream's exceptions mask, the exception will be rethrown 289 * without completing its actions. 290 */ 291 292 /** 293 * @brief Simple insertion. 294 * @param __c The character to insert. 295 * @return *this 296 * 297 * Tries to insert @p __c. 298 * 299 * @note This function is not overloaded on signed char and 300 * unsigned char. 301 */ 302 __ostream_type& 303 put(char_type __c); 304 305 /** 306 * @brief Core write functionality, without sentry. 307 * @param __s The array to insert. 308 * @param __n Maximum number of characters to insert. 309 */ 310 void 311 _M_write(const char_type* __s, streamsize __n) 312 { 313 const streamsize __put = this->rdbuf()->sputn(__s, __n); 314 if (__put != __n) 315 this->setstate(ios_base::badbit); 316 } 317 318 /** 319 * @brief Character string insertion. 320 * @param __s The array to insert. 321 * @param __n Maximum number of characters to insert. 322 * @return *this 323 * 324 * Characters are copied from @p __s and inserted into the stream until 325 * one of the following happens: 326 * 327 * - @p __n characters are inserted 328 * - inserting into the output sequence fails (in this case, badbit 329 * will be set in the stream's error state) 330 * 331 * @note This function is not overloaded on signed char and 332 * unsigned char. 333 */ 334 __ostream_type& 335 write(const char_type* __s, streamsize __n); 336 //@} 337 338 /** 339 * @brief Synchronizing the stream buffer. 340 * @return *this 341 * 342 * If @c rdbuf() is a null pointer, changes nothing. 343 * 344 * Otherwise, calls @c rdbuf()->pubsync(), and if that returns -1, 345 * sets badbit. 346 */ 347 __ostream_type& 348 flush(); 349 350 /** 351 * @brief Getting the current write position. 352 * @return A file position object. 353 * 354 * If @c fail() is not false, returns @c pos_type(-1) to indicate 355 * failure. Otherwise returns @c rdbuf()->pubseekoff(0,cur,out). 356 */ 357 pos_type 358 tellp(); 359 360 /** 361 * @brief Changing the current write position. 362 * @param __pos A file position object. 363 * @return *this 364 * 365 * If @c fail() is not true, calls @c rdbuf()->pubseekpos(pos). If 366 * that function fails, sets failbit. 367 */ 368 __ostream_type& 369 seekp(pos_type); 370 371 /** 372 * @brief Changing the current write position. 373 * @param __off A file offset object. 374 * @param __dir The direction in which to seek. 375 * @return *this 376 * 377 * If @c fail() is not true, calls @c rdbuf()->pubseekoff(off,dir). 378 * If that function fails, sets failbit. 379 */ 380 __ostream_type& 381 seekp(off_type, ios_base::seekdir); 382 383 protected: 384 basic_ostream() 385 { this->init(0); } 386 387 template<typename _ValueT> 388 __ostream_type& 389 _M_insert(_ValueT __v); 390 }; 391 392 /** 393 * @brief Performs setup work for output streams. 394 * 395 * Objects of this class are created before all of the standard 396 * inserters are run. It is responsible for <em>exception-safe prefix and 397 * suffix operations</em>. 398 */ 399 template <typename _CharT, typename _Traits> 400 class basic_ostream<_CharT, _Traits>::sentry 401 { 402 // Data Members. 403 bool _M_ok; 404 basic_ostream<_CharT, _Traits>& _M_os; 405 406 public: 407 /** 408 * @brief The constructor performs preparatory work. 409 * @param __os The output stream to guard. 410 * 411 * If the stream state is good (@a __os.good() is true), then if the 412 * stream is tied to another output stream, @c is.tie()->flush() 413 * is called to synchronize the output sequences. 414 * 415 * If the stream state is still good, then the sentry state becomes 416 * true (@a okay). 417 */ 418 explicit 419 sentry(basic_ostream<_CharT, _Traits>& __os); 420 421 /** 422 * @brief Possibly flushes the stream. 423 * 424 * If @c ios_base::unitbuf is set in @c os.flags(), and 425 * @c std::uncaught_exception() is true, the sentry destructor calls 426 * @c flush() on the output stream. 427 */ 428 ~sentry() 429 { 430 // XXX MT 431 if (bool(_M_os.flags() & ios_base::unitbuf) && !uncaught_exception()) 432 { 433 // Can't call flush directly or else will get into recursive lock. 434 if (_M_os.rdbuf() && _M_os.rdbuf()->pubsync() == -1) 435 _M_os.setstate(ios_base::badbit); 436 } 437 } 438 439 /** 440 * @brief Quick status checking. 441 * @return The sentry state. 442 * 443 * For ease of use, sentries may be converted to booleans. The 444 * return value is that of the sentry state (true == okay). 445 */ 446 #if __cplusplus >= 201103L 447 explicit 448 #endif 449 operator bool() const 450 { return _M_ok; } 451 }; 452 453 //@{ 454 /** 455 * @brief Character inserters 456 * @param __out An output stream. 457 * @param __c A character. 458 * @return out 459 * 460 * Behaves like one of the formatted arithmetic inserters described in 461 * std::basic_ostream. After constructing a sentry object with good 462 * status, this function inserts a single character and any required 463 * padding (as determined by [22.2.2.2.2]). @c __out.width(0) is then 464 * called. 465 * 466 * If @p __c is of type @c char and the character type of the stream is not 467 * @c char, the character is widened before insertion. 468 */ 469 template<typename _CharT, typename _Traits> 470 inline basic_ostream<_CharT, _Traits>& 471 operator<<(basic_ostream<_CharT, _Traits>& __out, _CharT __c) 472 { return __ostream_insert(__out, &__c, 1); } 473 474 template<typename _CharT, typename _Traits> 475 inline basic_ostream<_CharT, _Traits>& 476 operator<<(basic_ostream<_CharT, _Traits>& __out, char __c) 477 { return (__out << __out.widen(__c)); } 478 479 // Specialization 480 template <class _Traits> 481 inline basic_ostream<char, _Traits>& 482 operator<<(basic_ostream<char, _Traits>& __out, char __c) 483 { return __ostream_insert(__out, &__c, 1); } 484 485 // Signed and unsigned 486 template<class _Traits> 487 inline basic_ostream<char, _Traits>& 488 operator<<(basic_ostream<char, _Traits>& __out, signed char __c) 489 { return (__out << static_cast<char>(__c)); } 490 491 template<class _Traits> 492 inline basic_ostream<char, _Traits>& 493 operator<<(basic_ostream<char, _Traits>& __out, unsigned char __c) 494 { return (__out << static_cast<char>(__c)); } 495 //@} 496 497 //@{ 498 /** 499 * @brief String inserters 500 * @param __out An output stream. 501 * @param __s A character string. 502 * @return out 503 * @pre @p __s must be a non-NULL pointer 504 * 505 * Behaves like one of the formatted arithmetic inserters described in 506 * std::basic_ostream. After constructing a sentry object with good 507 * status, this function inserts @c traits::length(__s) characters starting 508 * at @p __s, widened if necessary, followed by any required padding (as 509 * determined by [22.2.2.2.2]). @c __out.width(0) is then called. 510 */ 511 template<typename _CharT, typename _Traits> 512 inline basic_ostream<_CharT, _Traits>& 513 operator<<(basic_ostream<_CharT, _Traits>& __out, const _CharT* __s) 514 { 515 if (!__s) 516 __out.setstate(ios_base::badbit); 517 else 518 __ostream_insert(__out, __s, 519 static_cast<streamsize>(_Traits::length(__s))); 520 return __out; 521 } 522 523 template<typename _CharT, typename _Traits> 524 basic_ostream<_CharT, _Traits> & 525 operator<<(basic_ostream<_CharT, _Traits>& __out, const char* __s); 526 527 // Partial specializations 528 template<class _Traits> 529 inline basic_ostream<char, _Traits>& 530 operator<<(basic_ostream<char, _Traits>& __out, const char* __s) 531 { 532 if (!__s) 533 __out.setstate(ios_base::badbit); 534 else 535 __ostream_insert(__out, __s, 536 static_cast<streamsize>(_Traits::length(__s))); 537 return __out; 538 } 539 540 // Signed and unsigned 541 template<class _Traits> 542 inline basic_ostream<char, _Traits>& 543 operator<<(basic_ostream<char, _Traits>& __out, const signed char* __s) 544 { return (__out << reinterpret_cast<const char*>(__s)); } 545 546 template<class _Traits> 547 inline basic_ostream<char, _Traits> & 548 operator<<(basic_ostream<char, _Traits>& __out, const unsigned char* __s) 549 { return (__out << reinterpret_cast<const char*>(__s)); } 550 //@} 551 552 // Standard basic_ostream manipulators 553 554 /** 555 * @brief Write a newline and flush the stream. 556 * 557 * This manipulator is often mistakenly used when a simple newline is 558 * desired, leading to poor buffering performance. See 559 * http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt11ch25s02.html 560 * for more on this subject. 561 */ 562 template<typename _CharT, typename _Traits> 563 inline basic_ostream<_CharT, _Traits>& 564 endl(basic_ostream<_CharT, _Traits>& __os) 565 { return flush(__os.put(__os.widen('\n'))); } 566 567 /** 568 * @brief Write a null character into the output sequence. 569 * 570 * <em>Null character</em> is @c CharT() by definition. For CharT 571 * of @c char, this correctly writes the ASCII @c NUL character 572 * string terminator. 573 */ 574 template<typename _CharT, typename _Traits> 575 inline basic_ostream<_CharT, _Traits>& 576 ends(basic_ostream<_CharT, _Traits>& __os) 577 { return __os.put(_CharT()); } 578 579 /** 580 * @brief Flushes the output stream. 581 * 582 * This manipulator simply calls the stream's @c flush() member function. 583 */ 584 template<typename _CharT, typename _Traits> 585 inline basic_ostream<_CharT, _Traits>& 586 flush(basic_ostream<_CharT, _Traits>& __os) 587 { return __os.flush(); } 588 589 #if __cplusplus >= 201103L 590 /** 591 * @brief Generic inserter for rvalue stream 592 * @param __os An input stream. 593 * @param __x A reference to the object being inserted. 594 * @return os 595 * 596 * This is just a forwarding function to allow insertion to 597 * rvalue streams since they won't bind to the inserter functions 598 * that take an lvalue reference. 599 */ 600 template<typename _CharT, typename _Traits, typename _Tp> 601 inline basic_ostream<_CharT, _Traits>& 602 operator<<(basic_ostream<_CharT, _Traits>&& __os, const _Tp& __x) 603 { return (__os << __x); } 604 #endif // C++11 605 606 _GLIBCXX_END_NAMESPACE_VERSION 607 } // namespace std 608 609 #include <bits/ostream.tcc> 610 611 #endif /* _GLIBCXX_OSTREAM */ 612
