1// Output streams -*- C++ -*- 2 3// Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 4// 2006, 2007 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 2, 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// You should have received a copy of the GNU General Public License along 19// with this library; see the file COPYING. If not, write to the Free 20// Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, 21// USA. 22 23// As a special exception, you may use this file as part of a free software 24// library without restriction. Specifically, if other files instantiate 25// templates or use macros or inline functions from this file, or you compile 26// this file and link it with other files to produce an executable, this 27// file does not by itself cause the resulting executable to be covered by 28// the GNU General Public License. This exception does not however 29// invalidate any other reasons why the executable file might be covered by 30// the GNU General Public License. 31 32/** @file ostream 33 * This is a Standard C++ Library header. 34 */ 35 36// 37// ISO C++ 14882: 27.6.2 Output streams 38// 39 40#ifndef _GLIBCXX_OSTREAM 41#define _GLIBCXX_OSTREAM 1 42 43#pragma GCC system_header 44 45#include <ios> 46#include <bits/ostream_insert.h> 47 48_GLIBCXX_BEGIN_NAMESPACE(std) 49 50 // [27.6.2.1] Template class basic_ostream 51 /** 52 * @brief Controlling output. 53 * 54 * This is the base class for all output streams. It provides text 55 * formatting of all builtin types, and communicates with any class 56 * derived from basic_streambuf to do the actual output. 57 */ 58 template<typename _CharT, typename _Traits> 59 class basic_ostream : virtual public basic_ios<_CharT, _Traits> 60 { 61 public: 62 // Types (inherited from basic_ios (27.4.4)): 63 typedef _CharT char_type; 64 typedef typename _Traits::int_type int_type; 65 typedef typename _Traits::pos_type pos_type; 66 typedef typename _Traits::off_type off_type; 67 typedef _Traits traits_type; 68 69 // Non-standard Types: 70 typedef basic_streambuf<_CharT, _Traits> __streambuf_type; 71 typedef basic_ios<_CharT, _Traits> __ios_type; 72 typedef basic_ostream<_CharT, _Traits> __ostream_type; 73 typedef num_put<_CharT, ostreambuf_iterator<_CharT, _Traits> > 74 __num_put_type; 75 typedef ctype<_CharT> __ctype_type; 76 77 // [27.6.2.2] constructor/destructor 78 /** 79 * @brief Base constructor. 80 * 81 * This ctor is almost never called by the user directly, rather from 82 * derived classes' initialization lists, which pass a pointer to 83 * their own stream buffer. 84 */ 85 explicit 86 basic_ostream(__streambuf_type* __sb) 87 { this->init(__sb); } 88 89 /** 90 * @brief Base destructor. 91 * 92 * This does very little apart from providing a virtual base dtor. 93 */ 94 virtual 95 ~basic_ostream() { } 96 97 // [27.6.2.3] prefix/suffix 98 class sentry; 99 friend class sentry; 100 101 // [27.6.2.5] formatted output 102 // [27.6.2.5.3] basic_ostream::operator<< 103 //@{ 104 /** 105 * @brief Interface for manipulators. 106 * 107 * Manuipulators such as @c std::endl and @c std::hex use these 108 * functions in constructs like "std::cout << std::endl". For more 109 * information, see the iomanip header. 110 */ 111 __ostream_type& 112 operator<<(__ostream_type& (*__pf)(__ostream_type&)) 113 { 114 // _GLIBCXX_RESOLVE_LIB_DEFECTS 115 // DR 60. What is a formatted input function? 116 // The inserters for manipulators are *not* formatted output functions. 117 return __pf(*this); 118 } 119 120 __ostream_type& 121 operator<<(__ios_type& (*__pf)(__ios_type&)) 122 { 123 // _GLIBCXX_RESOLVE_LIB_DEFECTS 124 // DR 60. What is a formatted input function? 125 // The inserters for manipulators are *not* formatted output functions. 126 __pf(*this); 127 return *this; 128 } 129 130 __ostream_type& 131 operator<<(ios_base& (*__pf) (ios_base&)) 132 { 133 // _GLIBCXX_RESOLVE_LIB_DEFECTS 134 // DR 60. What is a formatted input function? 135 // The inserters for manipulators are *not* formatted output functions. 136 __pf(*this); 137 return *this; 138 } 139 //@} 140 141 // [27.6.2.5.2] arithmetic inserters 142 /** 143 * @name Arithmetic Inserters 144 * 145 * All the @c operator<< functions (aka <em>formatted output 146 * functions</em>) have some common behavior. Each starts by 147 * constructing a temporary object of type std::basic_ostream::sentry. 148 * This can have several effects, concluding with the setting of a 149 * status flag; see the sentry documentation for more. 150 * 151 * If the sentry status is good, the function tries to generate 152 * whatever data is appropriate for the type of the argument. 153 * 154 * If an exception is thrown during insertion, ios_base::badbit 155 * will be turned on in the stream's error state without causing an 156 * ios_base::failure to be thrown. The original exception will then 157 * be rethrown. 158 */ 159 //@{ 160 /** 161 * @brief Basic arithmetic inserters 162 * @param A variable of builtin type. 163 * @return @c *this if successful 164 * 165 * These functions use the stream's current locale (specifically, the 166 * @c num_get facet) to perform numeric formatting. 167 */ 168 __ostream_type& 169 operator<<(long __n) 170 { return _M_insert(__n); } 171 172 __ostream_type& 173 operator<<(unsigned long __n) 174 { return _M_insert(__n); } 175 176 __ostream_type& 177 operator<<(bool __n) 178 { return _M_insert(__n); } 179 180 __ostream_type& 181 operator<<(short __n); 182 183 __ostream_type& 184 operator<<(unsigned short __n) 185 { 186 // _GLIBCXX_RESOLVE_LIB_DEFECTS 187 // 117. basic_ostream uses nonexistent num_put member functions. 188 return _M_insert(static_cast<unsigned long>(__n)); 189 } 190 191 __ostream_type& 192 operator<<(int __n); 193 194 __ostream_type& 195 operator<<(unsigned int __n) 196 { 197 // _GLIBCXX_RESOLVE_LIB_DEFECTS 198 // 117. basic_ostream uses nonexistent num_put member functions. 199 return _M_insert(static_cast<unsigned long>(__n)); 200 } 201 202#ifdef _GLIBCXX_USE_LONG_LONG 203 __ostream_type& 204 operator<<(long long __n) 205 { return _M_insert(__n); } 206 207 __ostream_type& 208 operator<<(unsigned long long __n) 209 { return _M_insert(__n); } 210#endif 211 212 __ostream_type& 213 operator<<(double __f) 214 { return _M_insert(__f); } 215 216 __ostream_type& 217 operator<<(float __f) 218 { 219 // _GLIBCXX_RESOLVE_LIB_DEFECTS 220 // 117. basic_ostream uses nonexistent num_put member functions. 221 return _M_insert(static_cast<double>(__f)); 222 } 223 224 __ostream_type& 225 operator<<(long double __f) 226 { return _M_insert(__f); } 227 228 __ostream_type& 229 operator<<(const void* __p) 230 { return _M_insert(__p); } 231 232 /** 233 * @brief Extracting from another streambuf. 234 * @param sb A pointer to a streambuf 235 * 236 * This function behaves like one of the basic arithmetic extractors, 237 * in that it also constructs a sentry object and has the same error 238 * handling behavior. 239 * 240 * If @a sb is NULL, the stream will set failbit in its error state. 241 * 242 * Characters are extracted from @a sb and inserted into @c *this 243 * until one of the following occurs: 244 * 245 * - the input stream reaches end-of-file, 246 * - insertion into the output sequence fails (in this case, the 247 * character that would have been inserted is not extracted), or 248 * - an exception occurs while getting a character from @a sb, which 249 * sets failbit in the error state 250 * 251 * If the function inserts no characters, failbit is set. 252 */ 253 __ostream_type& 254 operator<<(__streambuf_type* __sb); 255 //@} 256 257 // [27.6.2.6] unformatted output functions 258 /** 259 * @name Unformatted Output Functions 260 * 261 * All the unformatted output functions have some common behavior. 262 * Each starts by constructing a temporary object of type 263 * std::basic_ostream::sentry. This has several effects, concluding 264 * with the setting of a status flag; see the sentry documentation 265 * for more. 266 * 267 * If the sentry status is good, the function tries to generate 268 * whatever data is appropriate for the type of the argument. 269 * 270 * If an exception is thrown during insertion, ios_base::badbit 271 * will be turned on in the stream's error state. If badbit is on in 272 * the stream's exceptions mask, the exception will be rethrown 273 * without completing its actions. 274 */ 275 //@{ 276 /** 277 * @brief Simple insertion. 278 * @param c The character to insert. 279 * @return *this 280 * 281 * Tries to insert @a c. 282 * 283 * @note This function is not overloaded on signed char and 284 * unsigned char. 285 */ 286 __ostream_type& 287 put(char_type __c); 288 289 // Core write functionality, without sentry. 290 void 291 _M_write(const char_type* __s, streamsize __n) 292 { 293 const streamsize __put = this->rdbuf()->sputn(__s, __n); 294 if (__put != __n) 295 this->setstate(ios_base::badbit); 296 } 297 298 /** 299 * @brief Character string insertion. 300 * @param s The array to insert. 301 * @param n Maximum number of characters to insert. 302 * @return *this 303 * 304 * Characters are copied from @a s and inserted into the stream until 305 * one of the following happens: 306 * 307 * - @a n characters are inserted 308 * - inserting into the output sequence fails (in this case, badbit 309 * will be set in the stream's error state) 310 * 311 * @note This function is not overloaded on signed char and 312 * unsigned char. 313 */ 314 __ostream_type& 315 write(const char_type* __s, streamsize __n); 316 //@} 317 318 /** 319 * @brief Synchronizing the stream buffer. 320 * @return *this 321 * 322 * If @c rdbuf() is a null pointer, changes nothing. 323 * 324 * Otherwise, calls @c rdbuf()->pubsync(), and if that returns -1, 325 * sets badbit. 326 */ 327 __ostream_type& 328 flush(); 329 330 // [27.6.2.4] seek members 331 /** 332 * @brief Getting the current write position. 333 * @return A file position object. 334 * 335 * If @c fail() is not false, returns @c pos_type(-1) to indicate 336 * failure. Otherwise returns @c rdbuf()->pubseekoff(0,cur,out). 337 */ 338 pos_type 339 tellp(); 340 341 /** 342 * @brief Changing the current write position. 343 * @param pos A file position object. 344 * @return *this 345 * 346 * If @c fail() is not true, calls @c rdbuf()->pubseekpos(pos). If 347 * that function fails, sets failbit. 348 */ 349 __ostream_type& 350 seekp(pos_type); 351 352 /** 353 * @brief Changing the current write position. 354 * @param off A file offset object. 355 * @param dir The direction in which to seek. 356 * @return *this 357 * 358 * If @c fail() is not true, calls @c rdbuf()->pubseekoff(off,dir). 359 * If that function fails, sets failbit. 360 */ 361 __ostream_type& 362 seekp(off_type, ios_base::seekdir); 363 364 protected: 365 explicit 366 basic_ostream() { } 367 368 template<typename _ValueT> 369 __ostream_type& 370 _M_insert(_ValueT __v); 371 }; 372 373 /** 374 * @brief Performs setup work for output streams. 375 * 376 * Objects of this class are created before all of the standard 377 * inserters are run. It is responsible for "exception-safe prefix and 378 * suffix operations." Additional actions may be added by the 379 * implementation, and we list them in 380 * http://gcc.gnu.org/onlinedocs/libstdc++/17_intro/howto.html#5 381 * under [27.6] notes. 382 */ 383 template <typename _CharT, typename _Traits> 384 class basic_ostream<_CharT, _Traits>::sentry 385 { 386 // Data Members: 387 bool _M_ok; 388 basic_ostream<_CharT, _Traits>& _M_os; 389 390 public: 391 /** 392 * @brief The constructor performs preparatory work. 393 * @param os The output stream to guard. 394 * 395 * If the stream state is good (@a os.good() is true), then if the 396 * stream is tied to another output stream, @c is.tie()->flush() 397 * is called to synchronize the output sequences. 398 * 399 * If the stream state is still good, then the sentry state becomes 400 * true ("okay"). 401 */ 402 explicit 403 sentry(basic_ostream<_CharT, _Traits>& __os); 404 405 /** 406 * @brief Possibly flushes the stream. 407 * 408 * If @c ios_base::unitbuf is set in @c os.flags(), and 409 * @c std::uncaught_exception() is true, the sentry destructor calls 410 * @c flush() on the output stream. 411 */ 412 ~sentry() 413 { 414 // XXX MT 415 if (_M_os.flags() & ios_base::unitbuf && !uncaught_exception()) 416 { 417 // Can't call flush directly or else will get into recursive lock. 418 if (_M_os.rdbuf() && _M_os.rdbuf()->pubsync() == -1) 419 _M_os.setstate(ios_base::badbit); 420 } 421 } 422 423 /** 424 * @brief Quick status checking. 425 * @return The sentry state. 426 * 427 * For ease of use, sentries may be converted to booleans. The 428 * return value is that of the sentry state (true == okay). 429 */ 430 operator bool() const 431 { return _M_ok; } 432 }; 433 434 // [27.6.2.5.4] character insertion templates 435 //@{ 436 /** 437 * @brief Character inserters 438 * @param out An output stream. 439 * @param c A character. 440 * @return out 441 * 442 * Behaves like one of the formatted arithmetic inserters described in 443 * std::basic_ostream. After constructing a sentry object with good 444 * status, this function inserts a single character and any required 445 * padding (as determined by [22.2.2.2.2]). @c out.width(0) is then 446 * called. 447 * 448 * If @a c is of type @c char and the character type of the stream is not 449 * @c char, the character is widened before insertion. 450 */ 451 template<typename _CharT, typename _Traits> 452 inline basic_ostream<_CharT, _Traits>& 453 operator<<(basic_ostream<_CharT, _Traits>& __out, _CharT __c) 454 { return __ostream_insert(__out, &__c, 1); } 455 456 template<typename _CharT, typename _Traits> 457 inline basic_ostream<_CharT, _Traits>& 458 operator<<(basic_ostream<_CharT, _Traits>& __out, char __c) 459 { return (__out << __out.widen(__c)); } 460 461 // Specialization 462 template <class _Traits> 463 inline basic_ostream<char, _Traits>& 464 operator<<(basic_ostream<char, _Traits>& __out, char __c) 465 { return __ostream_insert(__out, &__c, 1); } 466 467 // Signed and unsigned 468 template<class _Traits> 469 inline basic_ostream<char, _Traits>& 470 operator<<(basic_ostream<char, _Traits>& __out, signed char __c) 471 { return (__out << static_cast<char>(__c)); } 472 473 template<class _Traits> 474 inline basic_ostream<char, _Traits>& 475 operator<<(basic_ostream<char, _Traits>& __out, unsigned char __c) 476 { return (__out << static_cast<char>(__c)); } 477 //@} 478 479 //@{ 480 /** 481 * @brief String inserters 482 * @param out An output stream. 483 * @param s A character string. 484 * @return out 485 * @pre @a s must be a non-NULL pointer 486 * 487 * Behaves like one of the formatted arithmetic inserters described in 488 * std::basic_ostream. After constructing a sentry object with good 489 * status, this function inserts @c traits::length(s) characters starting 490 * at @a s, widened if necessary, followed by any required padding (as 491 * determined by [22.2.2.2.2]). @c out.width(0) is then called. 492 */ 493 template<typename _CharT, typename _Traits> 494 inline basic_ostream<_CharT, _Traits>& 495 operator<<(basic_ostream<_CharT, _Traits>& __out, const _CharT* __s) 496 { 497 if (!__s) 498 __out.setstate(ios_base::badbit); 499 else 500 __ostream_insert(__out, __s, 501 static_cast<streamsize>(_Traits::length(__s))); 502 return __out; 503 } 504 505 template<typename _CharT, typename _Traits> 506 basic_ostream<_CharT, _Traits> & 507 operator<<(basic_ostream<_CharT, _Traits>& __out, const char* __s); 508 509 // Partial specializationss 510 template<class _Traits> 511 inline basic_ostream<char, _Traits>& 512 operator<<(basic_ostream<char, _Traits>& __out, const char* __s) 513 { 514 if (!__s) 515 __out.setstate(ios_base::badbit); 516 else 517 __ostream_insert(__out, __s, 518 static_cast<streamsize>(_Traits::length(__s))); 519 return __out; 520 } 521 522 // Signed and unsigned 523 template<class _Traits> 524 inline basic_ostream<char, _Traits>& 525 operator<<(basic_ostream<char, _Traits>& __out, const signed char* __s) 526 { return (__out << reinterpret_cast<const char*>(__s)); } 527 528 template<class _Traits> 529 inline basic_ostream<char, _Traits> & 530 operator<<(basic_ostream<char, _Traits>& __out, const unsigned char* __s) 531 { return (__out << reinterpret_cast<const char*>(__s)); } 532 //@} 533 534 // [27.6.2.7] standard basic_ostream manipulators 535 /** 536 * @brief Write a newline and flush the stream. 537 * 538 * This manipulator is often mistakenly used when a simple newline is 539 * desired, leading to poor buffering performance. See 540 * http://gcc.gnu.org/onlinedocs/libstdc++/27_io/howto.html#2 for more 541 * on this subject. 542 */ 543 template<typename _CharT, typename _Traits> 544 inline basic_ostream<_CharT, _Traits>& 545 endl(basic_ostream<_CharT, _Traits>& __os) 546 { return flush(__os.put(__os.widen('\n'))); } 547 548 /** 549 * @brief Write a null character into the output sequence. 550 * 551 * "Null character" is @c CharT() by definition. For CharT of @c char, 552 * this correctly writes the ASCII @c NUL character string terminator. 553 */ 554 template<typename _CharT, typename _Traits> 555 inline basic_ostream<_CharT, _Traits>& 556 ends(basic_ostream<_CharT, _Traits>& __os) 557 { return __os.put(_CharT()); } 558 559 /** 560 * @brief Flushes the output stream. 561 * 562 * This manipulator simply calls the stream's @c flush() member function. 563 */ 564 template<typename _CharT, typename _Traits> 565 inline basic_ostream<_CharT, _Traits>& 566 flush(basic_ostream<_CharT, _Traits>& __os) 567 { return __os.flush(); } 568 569_GLIBCXX_END_NAMESPACE 570 571#ifndef _GLIBCXX_EXPORT_TEMPLATE 572# include <bits/ostream.tcc> 573#endif 574 575#endif /* _GLIBCXX_OSTREAM */ 576