1 // File based 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 fstream 28 * This is a Standard C++ Library header. 29 */ 30 31 // 32 // ISO C++ 14882: 27.8 File-based streams 33 // 34 35 #ifndef _GLIBCXX_FSTREAM 36 #define _GLIBCXX_FSTREAM 1 37 38 #pragma GCC system_header 39 40 #include <istream> 41 #include <ostream> 42 #include <bits/codecvt.h> 43 #include <cstdio> // For BUFSIZ 44 #include <bits/basic_file.h> // For __basic_file, __c_lock 45 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 46 #include <string> // For std::string overloads. 47 #endif 48 49 _GLIBCXX_BEGIN_NAMESPACE(std) 50 51 // [27.8.1.1] template class basic_filebuf 52 /** 53 * @brief The actual work of input and output (for files). 54 * @ingroup io 55 * 56 * This class associates both its input and output sequence with an 57 * external disk file, and maintains a joint file position for both 58 * sequences. Many of its semantics are described in terms of similar 59 * behavior in the Standard C Library's @c FILE streams. 60 */ 61 // Requirements on traits_type, specific to this class: 62 // traits_type::pos_type must be fpos<traits_type::state_type> 63 // traits_type::off_type must be streamoff 64 // traits_type::state_type must be Assignable and DefaultConstructible, 65 // and traits_type::state_type() must be the initial state for codecvt. 66 template<typename _CharT, typename _Traits> 67 class basic_filebuf : public basic_streambuf<_CharT, _Traits> 68 { 69 public: 70 // Types: 71 typedef _CharT char_type; 72 typedef _Traits traits_type; 73 typedef typename traits_type::int_type int_type; 74 typedef typename traits_type::pos_type pos_type; 75 typedef typename traits_type::off_type off_type; 76 77 typedef basic_streambuf<char_type, traits_type> __streambuf_type; 78 typedef basic_filebuf<char_type, traits_type> __filebuf_type; 79 typedef __basic_file<char> __file_type; 80 typedef typename traits_type::state_type __state_type; 81 typedef codecvt<char_type, char, __state_type> __codecvt_type; 82 83 friend class ios_base; // For sync_with_stdio. 84 85 protected: 86 // Data Members: 87 // MT lock inherited from libio or other low-level io library. 88 __c_lock _M_lock; 89 90 // External buffer. 91 __file_type _M_file; 92 93 /// Place to stash in || out || in | out settings for current filebuf. 94 ios_base::openmode _M_mode; 95 96 // Beginning state type for codecvt. 97 __state_type _M_state_beg; 98 99 // During output, the state that corresponds to pptr(), 100 // during input, the state that corresponds to egptr() and 101 // _M_ext_next. 102 __state_type _M_state_cur; 103 104 // Not used for output. During input, the state that corresponds 105 // to eback() and _M_ext_buf. 106 __state_type _M_state_last; 107 108 /// Pointer to the beginning of internal buffer. 109 char_type* _M_buf; 110 111 /** 112 * Actual size of internal buffer. This number is equal to the size 113 * of the put area + 1 position, reserved for the overflow char of 114 * a full area. 115 */ 116 size_t _M_buf_size; 117 118 // Set iff _M_buf is allocated memory from _M_allocate_internal_buffer. 119 bool _M_buf_allocated; 120 121 /** 122 * _M_reading == false && _M_writing == false for 'uncommitted' mode; 123 * _M_reading == true for 'read' mode; 124 * _M_writing == true for 'write' mode; 125 * 126 * NB: _M_reading == true && _M_writing == true is unused. 127 */ 128 bool _M_reading; 129 bool _M_writing; 130 131 //@{ 132 /** 133 * Necessary bits for putback buffer management. 134 * 135 * @note pbacks of over one character are not currently supported. 136 */ 137 char_type _M_pback; 138 char_type* _M_pback_cur_save; 139 char_type* _M_pback_end_save; 140 bool _M_pback_init; 141 //@} 142 143 // Cached codecvt facet. 144 const __codecvt_type* _M_codecvt; 145 146 /** 147 * Buffer for external characters. Used for input when 148 * codecvt::always_noconv() == false. When valid, this corresponds 149 * to eback(). 150 */ 151 char* _M_ext_buf; 152 153 /** 154 * Size of buffer held by _M_ext_buf. 155 */ 156 streamsize _M_ext_buf_size; 157 158 /** 159 * Pointers into the buffer held by _M_ext_buf that delimit a 160 * subsequence of bytes that have been read but not yet converted. 161 * When valid, _M_ext_next corresponds to egptr(). 162 */ 163 const char* _M_ext_next; 164 char* _M_ext_end; 165 166 /** 167 * Initializes pback buffers, and moves normal buffers to safety. 168 * Assumptions: 169 * _M_in_cur has already been moved back 170 */ 171 void 172 _M_create_pback() 173 { 174 if (!_M_pback_init) 175 { 176 _M_pback_cur_save = this->gptr(); 177 _M_pback_end_save = this->egptr(); 178 this->setg(&_M_pback, &_M_pback, &_M_pback + 1); 179 _M_pback_init = true; 180 } 181 } 182 183 /** 184 * Deactivates pback buffer contents, and restores normal buffer. 185 * Assumptions: 186 * The pback buffer has only moved forward. 187 */ 188 void 189 _M_destroy_pback() throw() 190 { 191 if (_M_pback_init) 192 { 193 // Length _M_in_cur moved in the pback buffer. 194 _M_pback_cur_save += this->gptr() != this->eback(); 195 this->setg(_M_buf, _M_pback_cur_save, _M_pback_end_save); 196 _M_pback_init = false; 197 } 198 } 199 200 public: 201 // Constructors/destructor: 202 /** 203 * @brief Does not open any files. 204 * 205 * The default constructor initializes the parent class using its 206 * own default ctor. 207 */ 208 basic_filebuf(); 209 210 /** 211 * @brief The destructor closes the file first. 212 */ 213 virtual 214 ~basic_filebuf() 215 { this->close(); } 216 217 // Members: 218 /** 219 * @brief Returns true if the external file is open. 220 */ 221 bool 222 is_open() const throw() 223 { return _M_file.is_open(); } 224 225 /** 226 * @brief Opens an external file. 227 * @param s The name of the file. 228 * @param mode The open mode flags. 229 * @return @c this on success, NULL on failure 230 * 231 * If a file is already open, this function immediately fails. 232 * Otherwise it tries to open the file named @a s using the flags 233 * given in @a mode. 234 * 235 * Table 92, adapted here, gives the relation between openmode 236 * combinations and the equivalent fopen() flags. 237 * (NB: lines app, in|out|app, in|app, binary|app, binary|in|out|app, 238 * and binary|in|app per DR 596) 239 * +---------------------------------------------------------+ 240 * | ios_base Flag combination stdio equivalent | 241 * |binary in out trunc app | 242 * +---------------------------------------------------------+ 243 * | + "w" | 244 * | + + "a" | 245 * | + "a" | 246 * | + + "w" | 247 * | + "r" | 248 * | + + "r+" | 249 * | + + + "w+" | 250 * | + + + "a+" | 251 * | + + "a+" | 252 * +---------------------------------------------------------+ 253 * | + + "wb" | 254 * | + + + "ab" | 255 * | + + "ab" | 256 * | + + + "wb" | 257 * | + + "rb" | 258 * | + + + "r+b" | 259 * | + + + + "w+b" | 260 * | + + + + "a+b" | 261 * | + + + "a+b" | 262 * +---------------------------------------------------------+ 263 */ 264 __filebuf_type* 265 open(const char* __s, ios_base::openmode __mode); 266 267 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 268 /** 269 * @brief Opens an external file. 270 * @param s The name of the file. 271 * @param mode The open mode flags. 272 * @return @c this on success, NULL on failure 273 */ 274 __filebuf_type* 275 open(const std::string& __s, ios_base::openmode __mode) 276 { return open(__s.c_str(), __mode); } 277 #endif 278 279 /** 280 * @brief Closes the currently associated file. 281 * @return @c this on success, NULL on failure 282 * 283 * If no file is currently open, this function immediately fails. 284 * 285 * If a "put buffer area" exists, @c overflow(eof) is called to flush 286 * all the characters. The file is then closed. 287 * 288 * If any operations fail, this function also fails. 289 */ 290 __filebuf_type* 291 close(); 292 293 protected: 294 void 295 _M_allocate_internal_buffer(); 296 297 void 298 _M_destroy_internal_buffer() throw(); 299 300 // [27.8.1.4] overridden virtual functions 301 virtual streamsize 302 showmanyc(); 303 304 // Stroustrup, 1998, p. 628 305 // underflow() and uflow() functions are called to get the next 306 // character from the real input source when the buffer is empty. 307 // Buffered input uses underflow() 308 309 virtual int_type 310 underflow(); 311 312 virtual int_type 313 pbackfail(int_type __c = _Traits::eof()); 314 315 // Stroustrup, 1998, p 648 316 // The overflow() function is called to transfer characters to the 317 // real output destination when the buffer is full. A call to 318 // overflow(c) outputs the contents of the buffer plus the 319 // character c. 320 // 27.5.2.4.5 321 // Consume some sequence of the characters in the pending sequence. 322 virtual int_type 323 overflow(int_type __c = _Traits::eof()); 324 325 // Convert internal byte sequence to external, char-based 326 // sequence via codecvt. 327 bool 328 _M_convert_to_external(char_type*, streamsize); 329 330 /** 331 * @brief Manipulates the buffer. 332 * @param s Pointer to a buffer area. 333 * @param n Size of @a s. 334 * @return @c this 335 * 336 * If no file has been opened, and both @a s and @a n are zero, then 337 * the stream becomes unbuffered. Otherwise, @c s is used as a 338 * buffer; see 339 * http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt11ch25s02.html 340 * for more. 341 */ 342 virtual __streambuf_type* 343 setbuf(char_type* __s, streamsize __n); 344 345 virtual pos_type 346 seekoff(off_type __off, ios_base::seekdir __way, 347 ios_base::openmode __mode = ios_base::in | ios_base::out); 348 349 virtual pos_type 350 seekpos(pos_type __pos, 351 ios_base::openmode __mode = ios_base::in | ios_base::out); 352 353 // Common code for seekoff and seekpos 354 pos_type 355 _M_seek(off_type __off, ios_base::seekdir __way, __state_type __state); 356 357 virtual int 358 sync(); 359 360 virtual void 361 imbue(const locale& __loc); 362 363 virtual streamsize 364 xsgetn(char_type* __s, streamsize __n); 365 366 virtual streamsize 367 xsputn(const char_type* __s, streamsize __n); 368 369 // Flushes output buffer, then writes unshift sequence. 370 bool 371 _M_terminate_output(); 372 373 /** 374 * This function sets the pointers of the internal buffer, both get 375 * and put areas. Typically: 376 * 377 * __off == egptr() - eback() upon underflow/uflow ('read' mode); 378 * __off == 0 upon overflow ('write' mode); 379 * __off == -1 upon open, setbuf, seekoff/pos ('uncommitted' mode). 380 * 381 * NB: epptr() - pbase() == _M_buf_size - 1, since _M_buf_size 382 * reflects the actual allocated memory and the last cell is reserved 383 * for the overflow char of a full put area. 384 */ 385 void 386 _M_set_buffer(streamsize __off) 387 { 388 const bool __testin = _M_mode & ios_base::in; 389 const bool __testout = _M_mode & ios_base::out; 390 391 if (__testin && __off > 0) 392 this->setg(_M_buf, _M_buf, _M_buf + __off); 393 else 394 this->setg(_M_buf, _M_buf, _M_buf); 395 396 if (__testout && __off == 0 && _M_buf_size > 1 ) 397 this->setp(_M_buf, _M_buf + _M_buf_size - 1); 398 else 399 this->setp(NULL, NULL); 400 } 401 }; 402 403 // [27.8.1.5] Template class basic_ifstream 404 /** 405 * @brief Controlling input for files. 406 * @ingroup io 407 * 408 * This class supports reading from named files, using the inherited 409 * functions from std::basic_istream. To control the associated 410 * sequence, an instance of std::basic_filebuf is used, which this page 411 * refers to as @c sb. 412 */ 413 template<typename _CharT, typename _Traits> 414 class basic_ifstream : public basic_istream<_CharT, _Traits> 415 { 416 public: 417 // Types: 418 typedef _CharT char_type; 419 typedef _Traits traits_type; 420 typedef typename traits_type::int_type int_type; 421 typedef typename traits_type::pos_type pos_type; 422 typedef typename traits_type::off_type off_type; 423 424 // Non-standard types: 425 typedef basic_filebuf<char_type, traits_type> __filebuf_type; 426 typedef basic_istream<char_type, traits_type> __istream_type; 427 428 private: 429 __filebuf_type _M_filebuf; 430 431 public: 432 // Constructors/Destructors: 433 /** 434 * @brief Default constructor. 435 * 436 * Initializes @c sb using its default constructor, and passes 437 * @c &sb to the base class initializer. Does not open any files 438 * (you haven't given it a filename to open). 439 */ 440 basic_ifstream() : __istream_type(), _M_filebuf() 441 { this->init(&_M_filebuf); } 442 443 /** 444 * @brief Create an input file stream. 445 * @param s Null terminated string specifying the filename. 446 * @param mode Open file in specified mode (see std::ios_base). 447 * 448 * @c ios_base::in is automatically included in @a mode. 449 * 450 * Tip: When using std::string to hold the filename, you must use 451 * .c_str() before passing it to this constructor. 452 */ 453 explicit 454 basic_ifstream(const char* __s, ios_base::openmode __mode = ios_base::in) 455 : __istream_type(), _M_filebuf() 456 { 457 this->init(&_M_filebuf); 458 this->open(__s, __mode); 459 } 460 461 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 462 /** 463 * @brief Create an input file stream. 464 * @param s std::string specifying the filename. 465 * @param mode Open file in specified mode (see std::ios_base). 466 * 467 * @c ios_base::in is automatically included in @a mode. 468 */ 469 explicit 470 basic_ifstream(const std::string& __s, 471 ios_base::openmode __mode = ios_base::in) 472 : __istream_type(), _M_filebuf() 473 { 474 this->init(&_M_filebuf); 475 this->open(__s, __mode); 476 } 477 #endif 478 479 /** 480 * @brief The destructor does nothing. 481 * 482 * The file is closed by the filebuf object, not the formatting 483 * stream. 484 */ 485 ~basic_ifstream() 486 { } 487 488 // Members: 489 /** 490 * @brief Accessing the underlying buffer. 491 * @return The current basic_filebuf buffer. 492 * 493 * This hides both signatures of std::basic_ios::rdbuf(). 494 */ 495 __filebuf_type* 496 rdbuf() const 497 { return const_cast<__filebuf_type*>(&_M_filebuf); } 498 499 /** 500 * @brief Wrapper to test for an open file. 501 * @return @c rdbuf()->is_open() 502 */ 503 bool 504 is_open() 505 { return _M_filebuf.is_open(); } 506 507 // _GLIBCXX_RESOLVE_LIB_DEFECTS 508 // 365. Lack of const-qualification in clause 27 509 bool 510 is_open() const 511 { return _M_filebuf.is_open(); } 512 513 /** 514 * @brief Opens an external file. 515 * @param s The name of the file. 516 * @param mode The open mode flags. 517 * 518 * Calls @c std::basic_filebuf::open(s,mode|in). If that function 519 * fails, @c failbit is set in the stream's error state. 520 * 521 * Tip: When using std::string to hold the filename, you must use 522 * .c_str() before passing it to this constructor. 523 */ 524 void 525 open(const char* __s, ios_base::openmode __mode = ios_base::in) 526 { 527 if (!_M_filebuf.open(__s, __mode | ios_base::in)) 528 this->setstate(ios_base::failbit); 529 else 530 // _GLIBCXX_RESOLVE_LIB_DEFECTS 531 // 409. Closing an fstream should clear error state 532 this->clear(); 533 } 534 535 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 536 /** 537 * @brief Opens an external file. 538 * @param s The name of the file. 539 * @param mode The open mode flags. 540 * 541 * Calls @c std::basic_filebuf::open(s,mode|in). If that function 542 * fails, @c failbit is set in the stream's error state. 543 */ 544 void 545 open(const std::string& __s, ios_base::openmode __mode = ios_base::in) 546 { 547 if (!_M_filebuf.open(__s, __mode | ios_base::in)) 548 this->setstate(ios_base::failbit); 549 else 550 // _GLIBCXX_RESOLVE_LIB_DEFECTS 551 // 409. Closing an fstream should clear error state 552 this->clear(); 553 } 554 #endif 555 556 /** 557 * @brief Close the file. 558 * 559 * Calls @c std::basic_filebuf::close(). If that function 560 * fails, @c failbit is set in the stream's error state. 561 */ 562 void 563 close() 564 { 565 if (!_M_filebuf.close()) 566 this->setstate(ios_base::failbit); 567 } 568 }; 569 570 571 // [27.8.1.8] Template class basic_ofstream 572 /** 573 * @brief Controlling output for files. 574 * @ingroup io 575 * 576 * This class supports reading from named files, using the inherited 577 * functions from std::basic_ostream. To control the associated 578 * sequence, an instance of std::basic_filebuf is used, which this page 579 * refers to as @c sb. 580 */ 581 template<typename _CharT, typename _Traits> 582 class basic_ofstream : public basic_ostream<_CharT,_Traits> 583 { 584 public: 585 // Types: 586 typedef _CharT char_type; 587 typedef _Traits traits_type; 588 typedef typename traits_type::int_type int_type; 589 typedef typename traits_type::pos_type pos_type; 590 typedef typename traits_type::off_type off_type; 591 592 // Non-standard types: 593 typedef basic_filebuf<char_type, traits_type> __filebuf_type; 594 typedef basic_ostream<char_type, traits_type> __ostream_type; 595 596 private: 597 __filebuf_type _M_filebuf; 598 599 public: 600 // Constructors: 601 /** 602 * @brief Default constructor. 603 * 604 * Initializes @c sb using its default constructor, and passes 605 * @c &sb to the base class initializer. Does not open any files 606 * (you haven't given it a filename to open). 607 */ 608 basic_ofstream(): __ostream_type(), _M_filebuf() 609 { this->init(&_M_filebuf); } 610 611 /** 612 * @brief Create an output file stream. 613 * @param s Null terminated string specifying the filename. 614 * @param mode Open file in specified mode (see std::ios_base). 615 * 616 * @c ios_base::out|ios_base::trunc is automatically included in 617 * @a mode. 618 * 619 * Tip: When using std::string to hold the filename, you must use 620 * .c_str() before passing it to this constructor. 621 */ 622 explicit 623 basic_ofstream(const char* __s, 624 ios_base::openmode __mode = ios_base::out|ios_base::trunc) 625 : __ostream_type(), _M_filebuf() 626 { 627 this->init(&_M_filebuf); 628 this->open(__s, __mode); 629 } 630 631 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 632 /** 633 * @brief Create an output file stream. 634 * @param s std::string specifying the filename. 635 * @param mode Open file in specified mode (see std::ios_base). 636 * 637 * @c ios_base::out|ios_base::trunc is automatically included in 638 * @a mode. 639 */ 640 explicit 641 basic_ofstream(const std::string& __s, 642 ios_base::openmode __mode = ios_base::out|ios_base::trunc) 643 : __ostream_type(), _M_filebuf() 644 { 645 this->init(&_M_filebuf); 646 this->open(__s, __mode); 647 } 648 #endif 649 650 /** 651 * @brief The destructor does nothing. 652 * 653 * The file is closed by the filebuf object, not the formatting 654 * stream. 655 */ 656 ~basic_ofstream() 657 { } 658 659 // Members: 660 /** 661 * @brief Accessing the underlying buffer. 662 * @return The current basic_filebuf buffer. 663 * 664 * This hides both signatures of std::basic_ios::rdbuf(). 665 */ 666 __filebuf_type* 667 rdbuf() const 668 { return const_cast<__filebuf_type*>(&_M_filebuf); } 669 670 /** 671 * @brief Wrapper to test for an open file. 672 * @return @c rdbuf()->is_open() 673 */ 674 bool 675 is_open() 676 { return _M_filebuf.is_open(); } 677 678 // _GLIBCXX_RESOLVE_LIB_DEFECTS 679 // 365. Lack of const-qualification in clause 27 680 bool 681 is_open() const 682 { return _M_filebuf.is_open(); } 683 684 /** 685 * @brief Opens an external file. 686 * @param s The name of the file. 687 * @param mode The open mode flags. 688 * 689 * Calls @c std::basic_filebuf::open(s,mode|out|trunc). If that 690 * function fails, @c failbit is set in the stream's error state. 691 * 692 * Tip: When using std::string to hold the filename, you must use 693 * .c_str() before passing it to this constructor. 694 */ 695 void 696 open(const char* __s, 697 ios_base::openmode __mode = ios_base::out | ios_base::trunc) 698 { 699 if (!_M_filebuf.open(__s, __mode | ios_base::out)) 700 this->setstate(ios_base::failbit); 701 else 702 // _GLIBCXX_RESOLVE_LIB_DEFECTS 703 // 409. Closing an fstream should clear error state 704 this->clear(); 705 } 706 707 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 708 /** 709 * @brief Opens an external file. 710 * @param s The name of the file. 711 * @param mode The open mode flags. 712 * 713 * Calls @c std::basic_filebuf::open(s,mode|out|trunc). If that 714 * function fails, @c failbit is set in the stream's error state. 715 */ 716 void 717 open(const std::string& __s, 718 ios_base::openmode __mode = ios_base::out | ios_base::trunc) 719 { 720 if (!_M_filebuf.open(__s, __mode | ios_base::out)) 721 this->setstate(ios_base::failbit); 722 else 723 // _GLIBCXX_RESOLVE_LIB_DEFECTS 724 // 409. Closing an fstream should clear error state 725 this->clear(); 726 } 727 #endif 728 729 /** 730 * @brief Close the file. 731 * 732 * Calls @c std::basic_filebuf::close(). If that function 733 * fails, @c failbit is set in the stream's error state. 734 */ 735 void 736 close() 737 { 738 if (!_M_filebuf.close()) 739 this->setstate(ios_base::failbit); 740 } 741 }; 742 743 744 // [27.8.1.11] Template class basic_fstream 745 /** 746 * @brief Controlling input and output for files. 747 * @ingroup io 748 * 749 * This class supports reading from and writing to named files, using 750 * the inherited functions from std::basic_iostream. To control the 751 * associated sequence, an instance of std::basic_filebuf is used, which 752 * this page refers to as @c sb. 753 */ 754 template<typename _CharT, typename _Traits> 755 class basic_fstream : public basic_iostream<_CharT, _Traits> 756 { 757 public: 758 // Types: 759 typedef _CharT char_type; 760 typedef _Traits traits_type; 761 typedef typename traits_type::int_type int_type; 762 typedef typename traits_type::pos_type pos_type; 763 typedef typename traits_type::off_type off_type; 764 765 // Non-standard types: 766 typedef basic_filebuf<char_type, traits_type> __filebuf_type; 767 typedef basic_ios<char_type, traits_type> __ios_type; 768 typedef basic_iostream<char_type, traits_type> __iostream_type; 769 770 private: 771 __filebuf_type _M_filebuf; 772 773 public: 774 // Constructors/destructor: 775 /** 776 * @brief Default constructor. 777 * 778 * Initializes @c sb using its default constructor, and passes 779 * @c &sb to the base class initializer. Does not open any files 780 * (you haven't given it a filename to open). 781 */ 782 basic_fstream() 783 : __iostream_type(), _M_filebuf() 784 { this->init(&_M_filebuf); } 785 786 /** 787 * @brief Create an input/output file stream. 788 * @param s Null terminated string specifying the filename. 789 * @param mode Open file in specified mode (see std::ios_base). 790 * 791 * Tip: When using std::string to hold the filename, you must use 792 * .c_str() before passing it to this constructor. 793 */ 794 explicit 795 basic_fstream(const char* __s, 796 ios_base::openmode __mode = ios_base::in | ios_base::out) 797 : __iostream_type(NULL), _M_filebuf() 798 { 799 this->init(&_M_filebuf); 800 this->open(__s, __mode); 801 } 802 803 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 804 /** 805 * @brief Create an input/output file stream. 806 * @param s Null terminated string specifying the filename. 807 * @param mode Open file in specified mode (see std::ios_base). 808 */ 809 explicit 810 basic_fstream(const std::string& __s, 811 ios_base::openmode __mode = ios_base::in | ios_base::out) 812 : __iostream_type(NULL), _M_filebuf() 813 { 814 this->init(&_M_filebuf); 815 this->open(__s, __mode); 816 } 817 #endif 818 819 /** 820 * @brief The destructor does nothing. 821 * 822 * The file is closed by the filebuf object, not the formatting 823 * stream. 824 */ 825 ~basic_fstream() 826 { } 827 828 // Members: 829 /** 830 * @brief Accessing the underlying buffer. 831 * @return The current basic_filebuf buffer. 832 * 833 * This hides both signatures of std::basic_ios::rdbuf(). 834 */ 835 __filebuf_type* 836 rdbuf() const 837 { return const_cast<__filebuf_type*>(&_M_filebuf); } 838 839 /** 840 * @brief Wrapper to test for an open file. 841 * @return @c rdbuf()->is_open() 842 */ 843 bool 844 is_open() 845 { return _M_filebuf.is_open(); } 846 847 // _GLIBCXX_RESOLVE_LIB_DEFECTS 848 // 365. Lack of const-qualification in clause 27 849 bool 850 is_open() const 851 { return _M_filebuf.is_open(); } 852 853 /** 854 * @brief Opens an external file. 855 * @param s The name of the file. 856 * @param mode The open mode flags. 857 * 858 * Calls @c std::basic_filebuf::open(s,mode). If that 859 * function fails, @c failbit is set in the stream's error state. 860 * 861 * Tip: When using std::string to hold the filename, you must use 862 * .c_str() before passing it to this constructor. 863 */ 864 void 865 open(const char* __s, 866 ios_base::openmode __mode = ios_base::in | ios_base::out) 867 { 868 if (!_M_filebuf.open(__s, __mode)) 869 this->setstate(ios_base::failbit); 870 else 871 // _GLIBCXX_RESOLVE_LIB_DEFECTS 872 // 409. Closing an fstream should clear error state 873 this->clear(); 874 } 875 876 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 877 /** 878 * @brief Opens an external file. 879 * @param s The name of the file. 880 * @param mode The open mode flags. 881 * 882 * Calls @c std::basic_filebuf::open(s,mode). If that 883 * function fails, @c failbit is set in the stream's error state. 884 */ 885 void 886 open(const std::string& __s, 887 ios_base::openmode __mode = ios_base::in | ios_base::out) 888 { 889 if (!_M_filebuf.open(__s, __mode)) 890 this->setstate(ios_base::failbit); 891 else 892 // _GLIBCXX_RESOLVE_LIB_DEFECTS 893 // 409. Closing an fstream should clear error state 894 this->clear(); 895 } 896 #endif 897 898 /** 899 * @brief Close the file. 900 * 901 * Calls @c std::basic_filebuf::close(). If that function 902 * fails, @c failbit is set in the stream's error state. 903 */ 904 void 905 close() 906 { 907 if (!_M_filebuf.close()) 908 this->setstate(ios_base::failbit); 909 } 910 }; 911 912 _GLIBCXX_END_NAMESPACE 913 914 #ifndef _GLIBCXX_EXPORT_TEMPLATE 915 # include <bits/fstream.tcc> 916 #endif 917 918 #endif /* _GLIBCXX_FSTREAM */ 919
