1 // Output streams -*- C++ -*- 2 3 // Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 4 // 2006, 2007, 2008, 2009 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 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 _GLIBCXX_BEGIN_NAMESPACE(std) 44 45 // [27.6.2.1] Template class basic_ostream 46 /** 47 * @brief Controlling output. 48 * @ingroup io 49 * 50 * This is the base class for all output streams. It provides text 51 * formatting of all builtin types, and communicates with any class 52 * derived from basic_streambuf to do the actual output. 53 */ 54 template<typename _CharT, typename _Traits> 55 class basic_ostream : virtual public basic_ios<_CharT, _Traits> 56 { 57 public: 58 // Types (inherited from basic_ios (27.4.4)): 59 typedef _CharT char_type; 60 typedef typename _Traits::int_type int_type; 61 typedef typename _Traits::pos_type pos_type; 62 typedef typename _Traits::off_type off_type; 63 typedef _Traits traits_type; 64 65 // Non-standard Types: 66 typedef basic_streambuf<_CharT, _Traits> __streambuf_type; 67 typedef basic_ios<_CharT, _Traits> __ios_type; 68 typedef basic_ostream<_CharT, _Traits> __ostream_type; 69 typedef num_put<_CharT, ostreambuf_iterator<_CharT, _Traits> > 70 __num_put_type; 71 typedef ctype<_CharT> __ctype_type; 72 73 // [27.6.2.2] constructor/destructor 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 // [27.6.2.3] prefix/suffix 94 class sentry; 95 friend class sentry; 96 97 // [27.6.2.5] formatted output 98 // [27.6.2.5.3] basic_ostream::operator<< 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 // [27.6.2.5.2] arithmetic inserters 138 /** 139 * @name Arithmetic 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 * @brief Basic arithmetic inserters 158 * @param A variable of builtin type. 159 * @return @c *this if successful 160 * 161 * These functions use the stream's current locale (specifically, the 162 * @c num_get facet) to perform numeric formatting. 163 */ 164 __ostream_type& 165 operator<<(long __n) 166 { return _M_insert(__n); } 167 168 __ostream_type& 169 operator<<(unsigned long __n) 170 { return _M_insert(__n); } 171 172 __ostream_type& 173 operator<<(bool __n) 174 { return _M_insert(__n); } 175 176 __ostream_type& 177 operator<<(short __n); 178 179 __ostream_type& 180 operator<<(unsigned short __n) 181 { 182 // _GLIBCXX_RESOLVE_LIB_DEFECTS 183 // 117. basic_ostream uses nonexistent num_put member functions. 184 return _M_insert(static_cast<unsigned long>(__n)); 185 } 186 187 __ostream_type& 188 operator<<(int __n); 189 190 __ostream_type& 191 operator<<(unsigned int __n) 192 { 193 // _GLIBCXX_RESOLVE_LIB_DEFECTS 194 // 117. basic_ostream uses nonexistent num_put member functions. 195 return _M_insert(static_cast<unsigned long>(__n)); 196 } 197 198 #ifdef _GLIBCXX_USE_LONG_LONG 199 __ostream_type& 200 operator<<(long long __n) 201 { return _M_insert(__n); } 202 203 __ostream_type& 204 operator<<(unsigned long long __n) 205 { return _M_insert(__n); } 206 #endif 207 208 __ostream_type& 209 operator<<(double __f) 210 { return _M_insert(__f); } 211 212 __ostream_type& 213 operator<<(float __f) 214 { 215 // _GLIBCXX_RESOLVE_LIB_DEFECTS 216 // 117. basic_ostream uses nonexistent num_put member functions. 217 return _M_insert(static_cast<double>(__f)); 218 } 219 220 __ostream_type& 221 operator<<(long double __f) 222 { return _M_insert(__f); } 223 224 __ostream_type& 225 operator<<(const void* __p) 226 { return _M_insert(__p); } 227 228 /** 229 * @brief Extracting from another streambuf. 230 * @param sb A pointer to a streambuf 231 * 232 * This function behaves like one of the basic arithmetic extractors, 233 * in that it also constructs a sentry object and has the same error 234 * handling behavior. 235 * 236 * If @a sb is NULL, the stream will set failbit in its error state. 237 * 238 * Characters are extracted from @a sb and inserted into @c *this 239 * until one of the following occurs: 240 * 241 * - the input stream reaches end-of-file, 242 * - insertion into the output sequence fails (in this case, the 243 * character that would have been inserted is not extracted), or 244 * - an exception occurs while getting a character from @a sb, which 245 * sets failbit in the error state 246 * 247 * If the function inserts no characters, failbit is set. 248 */ 249 __ostream_type& 250 operator<<(__streambuf_type* __sb); 251 //@} 252 253 // [27.6.2.6] unformatted output functions 254 /** 255 * @name Unformatted Output Functions 256 * 257 * All the unformatted output functions have some common behavior. 258 * Each starts by constructing a temporary object of type 259 * std::basic_ostream::sentry. This has several effects, concluding 260 * with the setting of a status flag; see the sentry documentation 261 * for more. 262 * 263 * If the sentry status is good, the function tries to generate 264 * whatever data is appropriate for the type of the argument. 265 * 266 * If an exception is thrown during insertion, ios_base::badbit 267 * will be turned on in the stream's error state. If badbit is on in 268 * the stream's exceptions mask, the exception will be rethrown 269 * without completing its actions. 270 */ 271 //@{ 272 /** 273 * @brief Simple insertion. 274 * @param c The character to insert. 275 * @return *this 276 * 277 * Tries to insert @a c. 278 * 279 * @note This function is not overloaded on signed char and 280 * unsigned char. 281 */ 282 __ostream_type& 283 put(char_type __c); 284 285 // Core write functionality, without sentry. 286 void 287 _M_write(const char_type* __s, streamsize __n) 288 { 289 const streamsize __put = this->rdbuf()->sputn(__s, __n); 290 if (__put != __n) 291 this->setstate(ios_base::badbit); 292 } 293 294 /** 295 * @brief Character string insertion. 296 * @param s The array to insert. 297 * @param n Maximum number of characters to insert. 298 * @return *this 299 * 300 * Characters are copied from @a s and inserted into the stream until 301 * one of the following happens: 302 * 303 * - @a n characters are inserted 304 * - inserting into the output sequence fails (in this case, badbit 305 * will be set in the stream's error state) 306 * 307 * @note This function is not overloaded on signed char and 308 * unsigned char. 309 */ 310 __ostream_type& 311 write(const char_type* __s, streamsize __n); 312 //@} 313 314 /** 315 * @brief Synchronizing the stream buffer. 316 * @return *this 317 * 318 * If @c rdbuf() is a null pointer, changes nothing. 319 * 320 * Otherwise, calls @c rdbuf()->pubsync(), and if that returns -1, 321 * sets badbit. 322 */ 323 __ostream_type& 324 flush(); 325 326 // [27.6.2.4] seek members 327 /** 328 * @brief Getting the current write position. 329 * @return A file position object. 330 * 331 * If @c fail() is not false, returns @c pos_type(-1) to indicate 332 * failure. Otherwise returns @c rdbuf()->pubseekoff(0,cur,out). 333 */ 334 pos_type 335 tellp(); 336 337 /** 338 * @brief Changing the current write position. 339 * @param pos A file position object. 340 * @return *this 341 * 342 * If @c fail() is not true, calls @c rdbuf()->pubseekpos(pos). If 343 * that function fails, sets failbit. 344 */ 345 __ostream_type& 346 seekp(pos_type); 347 348 /** 349 * @brief Changing the current write position. 350 * @param off A file offset object. 351 * @param dir The direction in which to seek. 352 * @return *this 353 * 354 * If @c fail() is not true, calls @c rdbuf()->pubseekoff(off,dir). 355 * If that function fails, sets failbit. 356 */ 357 __ostream_type& 358 seekp(off_type, ios_base::seekdir); 359 360 protected: 361 basic_ostream() 362 { this->init(0); } 363 364 template<typename _ValueT> 365 __ostream_type& 366 _M_insert(_ValueT __v); 367 }; 368 369 /** 370 * @brief Performs setup work for output streams. 371 * 372 * Objects of this class are created before all of the standard 373 * inserters are run. It is responsible for "exception-safe prefix and 374 * suffix operations." 375 */ 376 template <typename _CharT, typename _Traits> 377 class basic_ostream<_CharT, _Traits>::sentry 378 { 379 // Data Members: 380 bool _M_ok; 381 basic_ostream<_CharT, _Traits>& _M_os; 382 383 public: 384 /** 385 * @brief The constructor performs preparatory work. 386 * @param os The output stream to guard. 387 * 388 * If the stream state is good (@a os.good() is true), then if the 389 * stream is tied to another output stream, @c is.tie()->flush() 390 * is called to synchronize the output sequences. 391 * 392 * If the stream state is still good, then the sentry state becomes 393 * true ("okay"). 394 */ 395 explicit 396 sentry(basic_ostream<_CharT, _Traits>& __os); 397 398 /** 399 * @brief Possibly flushes the stream. 400 * 401 * If @c ios_base::unitbuf is set in @c os.flags(), and 402 * @c std::uncaught_exception() is true, the sentry destructor calls 403 * @c flush() on the output stream. 404 */ 405 ~sentry() 406 { 407 // XXX MT 408 if (bool(_M_os.flags() & ios_base::unitbuf) && !uncaught_exception()) 409 { 410 // Can't call flush directly or else will get into recursive lock. 411 if (_M_os.rdbuf() && _M_os.rdbuf()->pubsync() == -1) 412 _M_os.setstate(ios_base::badbit); 413 } 414 } 415 416 /** 417 * @brief Quick status checking. 418 * @return The sentry state. 419 * 420 * For ease of use, sentries may be converted to booleans. The 421 * return value is that of the sentry state (true == okay). 422 */ 423 operator bool() const 424 { return _M_ok; } 425 }; 426 427 // [27.6.2.5.4] character insertion templates 428 //@{ 429 /** 430 * @brief Character inserters 431 * @param out An output stream. 432 * @param c A character. 433 * @return out 434 * 435 * Behaves like one of the formatted arithmetic inserters described in 436 * std::basic_ostream. After constructing a sentry object with good 437 * status, this function inserts a single character and any required 438 * padding (as determined by [22.2.2.2.2]). @c out.width(0) is then 439 * called. 440 * 441 * If @a c is of type @c char and the character type of the stream is not 442 * @c char, the character is widened before insertion. 443 */ 444 template<typename _CharT, typename _Traits> 445 inline basic_ostream<_CharT, _Traits>& 446 operator<<(basic_ostream<_CharT, _Traits>& __out, _CharT __c) 447 { return __ostream_insert(__out, &__c, 1); } 448 449 template<typename _CharT, typename _Traits> 450 inline basic_ostream<_CharT, _Traits>& 451 operator<<(basic_ostream<_CharT, _Traits>& __out, char __c) 452 { return (__out << __out.widen(__c)); } 453 454 // Specialization 455 template <class _Traits> 456 inline basic_ostream<char, _Traits>& 457 operator<<(basic_ostream<char, _Traits>& __out, char __c) 458 { return __ostream_insert(__out, &__c, 1); } 459 460 // Signed and unsigned 461 template<class _Traits> 462 inline basic_ostream<char, _Traits>& 463 operator<<(basic_ostream<char, _Traits>& __out, signed char __c) 464 { return (__out << static_cast<char>(__c)); } 465 466 template<class _Traits> 467 inline basic_ostream<char, _Traits>& 468 operator<<(basic_ostream<char, _Traits>& __out, unsigned char __c) 469 { return (__out << static_cast<char>(__c)); } 470 //@} 471 472 //@{ 473 /** 474 * @brief String inserters 475 * @param out An output stream. 476 * @param s A character string. 477 * @return out 478 * @pre @a s must be a non-NULL pointer 479 * 480 * Behaves like one of the formatted arithmetic inserters described in 481 * std::basic_ostream. After constructing a sentry object with good 482 * status, this function inserts @c traits::length(s) characters starting 483 * at @a s, widened if necessary, followed by any required padding (as 484 * determined by [22.2.2.2.2]). @c out.width(0) is then called. 485 */ 486 template<typename _CharT, typename _Traits> 487 inline basic_ostream<_CharT, _Traits>& 488 operator<<(basic_ostream<_CharT, _Traits>& __out, const _CharT* __s) 489 { 490 if (!__s) 491 __out.setstate(ios_base::badbit); 492 else 493 __ostream_insert(__out, __s, 494 static_cast<streamsize>(_Traits::length(__s))); 495 return __out; 496 } 497 498 template<typename _CharT, typename _Traits> 499 basic_ostream<_CharT, _Traits> & 500 operator<<(basic_ostream<_CharT, _Traits>& __out, const char* __s); 501 502 // Partial specializations 503 template<class _Traits> 504 inline basic_ostream<char, _Traits>& 505 operator<<(basic_ostream<char, _Traits>& __out, const char* __s) 506 { 507 if (!__s) 508 __out.setstate(ios_base::badbit); 509 else 510 __ostream_insert(__out, __s, 511 static_cast<streamsize>(_Traits::length(__s))); 512 return __out; 513 } 514 515 // Signed and unsigned 516 template<class _Traits> 517 inline basic_ostream<char, _Traits>& 518 operator<<(basic_ostream<char, _Traits>& __out, const signed char* __s) 519 { return (__out << reinterpret_cast<const char*>(__s)); } 520 521 template<class _Traits> 522 inline basic_ostream<char, _Traits> & 523 operator<<(basic_ostream<char, _Traits>& __out, const unsigned char* __s) 524 { return (__out << reinterpret_cast<const char*>(__s)); } 525 //@} 526 527 // [27.6.2.7] standard basic_ostream manipulators 528 /** 529 * @brief Write a newline and flush the stream. 530 * 531 * This manipulator is often mistakenly used when a simple newline is 532 * desired, leading to poor buffering performance. See 533 * http://gcc.gnu.org/onlinedocs/libstdc++/27_io/howto.html#2 for more 534 * on this subject. 535 */ 536 template<typename _CharT, typename _Traits> 537 inline basic_ostream<_CharT, _Traits>& 538 endl(basic_ostream<_CharT, _Traits>& __os) 539 { return flush(__os.put(__os.widen('\n'))); } 540 541 /** 542 * @brief Write a null character into the output sequence. 543 * 544 * "Null character" is @c CharT() by definition. For CharT of @c char, 545 * this correctly writes the ASCII @c NUL character string terminator. 546 */ 547 template<typename _CharT, typename _Traits> 548 inline basic_ostream<_CharT, _Traits>& 549 ends(basic_ostream<_CharT, _Traits>& __os) 550 { return __os.put(_CharT()); } 551 552 /** 553 * @brief Flushes the output stream. 554 * 555 * This manipulator simply calls the stream's @c flush() member function. 556 */ 557 template<typename _CharT, typename _Traits> 558 inline basic_ostream<_CharT, _Traits>& 559 flush(basic_ostream<_CharT, _Traits>& __os) 560 { return __os.flush(); } 561 562 _GLIBCXX_END_NAMESPACE 563 564 #ifndef _GLIBCXX_EXPORT_TEMPLATE 565 # include <bits/ostream.tcc> 566 #endif 567 568 #endif /* _GLIBCXX_OSTREAM */ 569
