1 // File based streams -*- C++ -*- 2 3 // Copyright (C) 1997-2013 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/fstream 26 * This is a Standard C++ Library header. 27 */ 28 29 // 30 // ISO C++ 14882: 27.8 File-based streams 31 // 32 33 #ifndef _GLIBCXX_FSTREAM 34 #define _GLIBCXX_FSTREAM 1 35 36 #pragma GCC system_header 37 38 #include <istream> 39 #include <ostream> 40 #include <bits/codecvt.h> 41 #include <cstdio> // For BUFSIZ 42 #include <bits/basic_file.h> // For __basic_file, __c_lock 43 #if __cplusplus >= 201103L 44 #include <string> // For std::string overloads. 45 #endif 46 47 namespace std _GLIBCXX_VISIBILITY(default) 48 { 49 _GLIBCXX_BEGIN_NAMESPACE_VERSION 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 * @tparam _CharT Type of character stream. 57 * @tparam _Traits Traits for character type, defaults to 58 * char_traits<_CharT>. 59 * 60 * This class associates both its input and output sequence with an 61 * external disk file, and maintains a joint file position for both 62 * sequences. Many of its semantics are described in terms of similar 63 * behavior in the Standard C Library's @c FILE streams. 64 * 65 * Requirements on traits_type, specific to this class: 66 * - traits_type::pos_type must be fpos<traits_type::state_type> 67 * - traits_type::off_type must be streamoff 68 * - traits_type::state_type must be Assignable and DefaultConstructible, 69 * - traits_type::state_type() must be the initial state for codecvt. 70 */ 71 template<typename _CharT, typename _Traits> 72 class basic_filebuf : public basic_streambuf<_CharT, _Traits> 73 { 74 public: 75 // Types: 76 typedef _CharT char_type; 77 typedef _Traits traits_type; 78 typedef typename traits_type::int_type int_type; 79 typedef typename traits_type::pos_type pos_type; 80 typedef typename traits_type::off_type off_type; 81 82 typedef basic_streambuf<char_type, traits_type> __streambuf_type; 83 typedef basic_filebuf<char_type, traits_type> __filebuf_type; 84 typedef __basic_file<char> __file_type; 85 typedef typename traits_type::state_type __state_type; 86 typedef codecvt<char_type, char, __state_type> __codecvt_type; 87 88 friend class ios_base; // For sync_with_stdio. 89 90 protected: 91 // Data Members: 92 // MT lock inherited from libio or other low-level io library. 93 __c_lock _M_lock; 94 95 // External buffer. 96 __file_type _M_file; 97 98 /// Place to stash in || out || in | out settings for current filebuf. 99 ios_base::openmode _M_mode; 100 101 // Beginning state type for codecvt. 102 __state_type _M_state_beg; 103 104 // During output, the state that corresponds to pptr(), 105 // during input, the state that corresponds to egptr() and 106 // _M_ext_next. 107 __state_type _M_state_cur; 108 109 // Not used for output. During input, the state that corresponds 110 // to eback() and _M_ext_buf. 111 __state_type _M_state_last; 112 113 /// Pointer to the beginning of internal buffer. 114 char_type* _M_buf; 115 116 /** 117 * Actual size of internal buffer. This number is equal to the size 118 * of the put area + 1 position, reserved for the overflow char of 119 * a full area. 120 */ 121 size_t _M_buf_size; 122 123 // Set iff _M_buf is allocated memory from _M_allocate_internal_buffer. 124 bool _M_buf_allocated; 125 126 /** 127 * _M_reading == false && _M_writing == false for @b uncommitted mode; 128 * _M_reading == true for @b read mode; 129 * _M_writing == true for @b write mode; 130 * 131 * NB: _M_reading == true && _M_writing == true is unused. 132 */ 133 bool _M_reading; 134 bool _M_writing; 135 136 //@{ 137 /** 138 * Necessary bits for putback buffer management. 139 * 140 * @note pbacks of over one character are not currently supported. 141 */ 142 char_type _M_pback; 143 char_type* _M_pback_cur_save; 144 char_type* _M_pback_end_save; 145 bool _M_pback_init; 146 //@} 147 148 // Cached codecvt facet. 149 const __codecvt_type* _M_codecvt; 150 151 /** 152 * Buffer for external characters. Used for input when 153 * codecvt::always_noconv() == false. When valid, this corresponds 154 * to eback(). 155 */ 156 char* _M_ext_buf; 157 158 /** 159 * Size of buffer held by _M_ext_buf. 160 */ 161 streamsize _M_ext_buf_size; 162 163 /** 164 * Pointers into the buffer held by _M_ext_buf that delimit a 165 * subsequence of bytes that have been read but not yet converted. 166 * When valid, _M_ext_next corresponds to egptr(). 167 */ 168 const char* _M_ext_next; 169 char* _M_ext_end; 170 171 /** 172 * Initializes pback buffers, and moves normal buffers to safety. 173 * Assumptions: 174 * _M_in_cur has already been moved back 175 */ 176 void 177 _M_create_pback() 178 { 179 if (!_M_pback_init) 180 { 181 _M_pback_cur_save = this->gptr(); 182 _M_pback_end_save = this->egptr(); 183 this->setg(&_M_pback, &_M_pback, &_M_pback + 1); 184 _M_pback_init = true; 185 } 186 } 187 188 /** 189 * Deactivates pback buffer contents, and restores normal buffer. 190 * Assumptions: 191 * The pback buffer has only moved forward. 192 */ 193 void 194 _M_destroy_pback() throw() 195 { 196 if (_M_pback_init) 197 { 198 // Length _M_in_cur moved in the pback buffer. 199 _M_pback_cur_save += this->gptr() != this->eback(); 200 this->setg(_M_buf, _M_pback_cur_save, _M_pback_end_save); 201 _M_pback_init = false; 202 } 203 } 204 205 public: 206 // Constructors/destructor: 207 /** 208 * @brief Does not open any files. 209 * 210 * The default constructor initializes the parent class using its 211 * own default ctor. 212 */ 213 basic_filebuf(); 214 215 /** 216 * @brief The destructor closes the file first. 217 */ 218 virtual 219 ~basic_filebuf() 220 { this->close(); } 221 222 // Members: 223 /** 224 * @brief Returns true if the external file is open. 225 */ 226 bool 227 is_open() const throw() 228 { return _M_file.is_open(); } 229 230 /** 231 * @brief Opens an external file. 232 * @param __s The name of the file. 233 * @param __mode The open mode flags. 234 * @return @c this on success, NULL on failure 235 * 236 * If a file is already open, this function immediately fails. 237 * Otherwise it tries to open the file named @a __s using the flags 238 * given in @a __mode. 239 * 240 * Table 92, adapted here, gives the relation between openmode 241 * combinations and the equivalent fopen() flags. 242 * (NB: lines app, in|out|app, in|app, binary|app, binary|in|out|app, 243 * and binary|in|app per DR 596) 244 * +---------------------------------------------------------+ 245 * | ios_base Flag combination stdio equivalent | 246 * |binary in out trunc app | 247 * +---------------------------------------------------------+ 248 * | + w | 249 * | + + a | 250 * | + a | 251 * | + + w | 252 * | + r | 253 * | + + r+ | 254 * | + + + w+ | 255 * | + + + a+ | 256 * | + + a+ | 257 * +---------------------------------------------------------+ 258 * | + + wb | 259 * | + + + ab | 260 * | + + ab | 261 * | + + + wb | 262 * | + + rb | 263 * | + + + r+b | 264 * | + + + + w+b | 265 * | + + + + a+b | 266 * | + + + a+b | 267 * +---------------------------------------------------------+ 268 */ 269 __filebuf_type* 270 open(const char* __s, ios_base::openmode __mode); 271 272 #if __cplusplus >= 201103L 273 /** 274 * @brief Opens an external file. 275 * @param __s The name of the file. 276 * @param __mode The open mode flags. 277 * @return @c this on success, NULL on failure 278 */ 279 __filebuf_type* 280 open(const std::string& __s, ios_base::openmode __mode) 281 { return open(__s.c_str(), __mode); } 282 #endif 283 284 /** 285 * @brief Closes the currently associated file. 286 * @return @c this on success, NULL on failure 287 * 288 * If no file is currently open, this function immediately fails. 289 * 290 * If a <em>put buffer area</em> exists, @c overflow(eof) is 291 * called to flush all the characters. The file is then 292 * closed. 293 * 294 * If any operations fail, this function also fails. 295 */ 296 __filebuf_type* 297 close(); 298 299 protected: 300 void 301 _M_allocate_internal_buffer(); 302 303 void 304 _M_destroy_internal_buffer() throw(); 305 306 // [27.8.1.4] overridden virtual functions 307 virtual streamsize 308 showmanyc(); 309 310 // Stroustrup, 1998, p. 628 311 // underflow() and uflow() functions are called to get the next 312 // character from the real input source when the buffer is empty. 313 // Buffered input uses underflow() 314 315 virtual int_type 316 underflow(); 317 318 virtual int_type 319 pbackfail(int_type __c = _Traits::eof()); 320 321 // Stroustrup, 1998, p 648 322 // The overflow() function is called to transfer characters to the 323 // real output destination when the buffer is full. A call to 324 // overflow(c) outputs the contents of the buffer plus the 325 // character c. 326 // 27.5.2.4.5 327 // Consume some sequence of the characters in the pending sequence. 328 virtual int_type 329 overflow(int_type __c = _Traits::eof()); 330 331 // Convert internal byte sequence to external, char-based 332 // sequence via codecvt. 333 bool 334 _M_convert_to_external(char_type*, streamsize); 335 336 /** 337 * @brief Manipulates the buffer. 338 * @param __s Pointer to a buffer area. 339 * @param __n Size of @a __s. 340 * @return @c this 341 * 342 * If no file has been opened, and both @a __s and @a __n are zero, then 343 * the stream becomes unbuffered. Otherwise, @c __s is used as a 344 * buffer; see 345 * http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt11ch25s02.html 346 * for more. 347 */ 348 virtual __streambuf_type* 349 setbuf(char_type* __s, streamsize __n); 350 351 virtual pos_type 352 seekoff(off_type __off, ios_base::seekdir __way, 353 ios_base::openmode __mode = ios_base::in | ios_base::out); 354 355 virtual pos_type 356 seekpos(pos_type __pos, 357 ios_base::openmode __mode = ios_base::in | ios_base::out); 358 359 // Common code for seekoff, seekpos, and overflow 360 pos_type 361 _M_seek(off_type __off, ios_base::seekdir __way, __state_type __state); 362 363 int 364 _M_get_ext_pos(__state_type &__state); 365 366 virtual int 367 sync(); 368 369 virtual void 370 imbue(const locale& __loc); 371 372 virtual streamsize 373 xsgetn(char_type* __s, streamsize __n); 374 375 virtual streamsize 376 xsputn(const char_type* __s, streamsize __n); 377 378 // Flushes output buffer, then writes unshift sequence. 379 bool 380 _M_terminate_output(); 381 382 /** 383 * This function sets the pointers of the internal buffer, both get 384 * and put areas. Typically: 385 * 386 * __off == egptr() - eback() upon underflow/uflow (@b read mode); 387 * __off == 0 upon overflow (@b write mode); 388 * __off == -1 upon open, setbuf, seekoff/pos (@b uncommitted mode). 389 * 390 * NB: epptr() - pbase() == _M_buf_size - 1, since _M_buf_size 391 * reflects the actual allocated memory and the last cell is reserved 392 * for the overflow char of a full put area. 393 */ 394 void 395 _M_set_buffer(streamsize __off) 396 { 397 const bool __testin = _M_mode & ios_base::in; 398 const bool __testout = _M_mode & ios_base::out; 399 400 if (__testin && __off > 0) 401 this->setg(_M_buf, _M_buf, _M_buf + __off); 402 else 403 this->setg(_M_buf, _M_buf, _M_buf); 404 405 if (__testout && __off == 0 && _M_buf_size > 1 ) 406 this->setp(_M_buf, _M_buf + _M_buf_size - 1); 407 else 408 this->setp(0, 0); 409 } 410 }; 411 412 // [27.8.1.5] Template class basic_ifstream 413 /** 414 * @brief Controlling input for files. 415 * @ingroup io 416 * 417 * @tparam _CharT Type of character stream. 418 * @tparam _Traits Traits for character type, defaults to 419 * char_traits<_CharT>. 420 * 421 * This class supports reading from named files, using the inherited 422 * functions from std::basic_istream. To control the associated 423 * sequence, an instance of std::basic_filebuf is used, which this page 424 * refers to as @c sb. 425 */ 426 template<typename _CharT, typename _Traits> 427 class basic_ifstream : public basic_istream<_CharT, _Traits> 428 { 429 public: 430 // Types: 431 typedef _CharT char_type; 432 typedef _Traits traits_type; 433 typedef typename traits_type::int_type int_type; 434 typedef typename traits_type::pos_type pos_type; 435 typedef typename traits_type::off_type off_type; 436 437 // Non-standard types: 438 typedef basic_filebuf<char_type, traits_type> __filebuf_type; 439 typedef basic_istream<char_type, traits_type> __istream_type; 440 441 private: 442 __filebuf_type _M_filebuf; 443 444 public: 445 // Constructors/Destructors: 446 /** 447 * @brief Default constructor. 448 * 449 * Initializes @c sb using its default constructor, and passes 450 * @c &sb to the base class initializer. Does not open any files 451 * (you haven't given it a filename to open). 452 */ 453 basic_ifstream() : __istream_type(), _M_filebuf() 454 { this->init(&_M_filebuf); } 455 456 /** 457 * @brief Create an input file stream. 458 * @param __s Null terminated string specifying the filename. 459 * @param __mode Open file in specified mode (see std::ios_base). 460 * 461 * @c ios_base::in is automatically included in @a __mode. 462 * 463 * Tip: When using std::string to hold the filename, you must use 464 * .c_str() before passing it to this constructor. 465 */ 466 explicit 467 basic_ifstream(const char* __s, ios_base::openmode __mode = ios_base::in) 468 : __istream_type(), _M_filebuf() 469 { 470 this->init(&_M_filebuf); 471 this->open(__s, __mode); 472 } 473 474 #if __cplusplus >= 201103L 475 /** 476 * @brief Create an input file stream. 477 * @param __s std::string specifying the filename. 478 * @param __mode Open file in specified mode (see std::ios_base). 479 * 480 * @c ios_base::in is automatically included in @a __mode. 481 */ 482 explicit 483 basic_ifstream(const std::string& __s, 484 ios_base::openmode __mode = ios_base::in) 485 : __istream_type(), _M_filebuf() 486 { 487 this->init(&_M_filebuf); 488 this->open(__s, __mode); 489 } 490 #endif 491 492 /** 493 * @brief The destructor does nothing. 494 * 495 * The file is closed by the filebuf object, not the formatting 496 * stream. 497 */ 498 ~basic_ifstream() 499 { } 500 501 // Members: 502 /** 503 * @brief Accessing the underlying buffer. 504 * @return The current basic_filebuf buffer. 505 * 506 * This hides both signatures of std::basic_ios::rdbuf(). 507 */ 508 __filebuf_type* 509 rdbuf() const 510 { return const_cast<__filebuf_type*>(&_M_filebuf); } 511 512 /** 513 * @brief Wrapper to test for an open file. 514 * @return @c rdbuf()->is_open() 515 */ 516 bool 517 is_open() 518 { return _M_filebuf.is_open(); } 519 520 // _GLIBCXX_RESOLVE_LIB_DEFECTS 521 // 365. Lack of const-qualification in clause 27 522 bool 523 is_open() const 524 { return _M_filebuf.is_open(); } 525 526 /** 527 * @brief Opens an external file. 528 * @param __s The name of the file. 529 * @param __mode The open mode flags. 530 * 531 * Calls @c std::basic_filebuf::open(s,__mode|in). If that function 532 * fails, @c failbit is set in the stream's error state. 533 * 534 * Tip: When using std::string to hold the filename, you must use 535 * .c_str() before passing it to this constructor. 536 */ 537 void 538 open(const char* __s, ios_base::openmode __mode = ios_base::in) 539 { 540 if (!_M_filebuf.open(__s, __mode | ios_base::in)) 541 this->setstate(ios_base::failbit); 542 else 543 // _GLIBCXX_RESOLVE_LIB_DEFECTS 544 // 409. Closing an fstream should clear error state 545 this->clear(); 546 } 547 548 #if __cplusplus >= 201103L 549 /** 550 * @brief Opens an external file. 551 * @param __s The name of the file. 552 * @param __mode The open mode flags. 553 * 554 * Calls @c std::basic_filebuf::open(__s,__mode|in). If that function 555 * fails, @c failbit is set in the stream's error state. 556 */ 557 void 558 open(const std::string& __s, ios_base::openmode __mode = ios_base::in) 559 { 560 if (!_M_filebuf.open(__s, __mode | ios_base::in)) 561 this->setstate(ios_base::failbit); 562 else 563 // _GLIBCXX_RESOLVE_LIB_DEFECTS 564 // 409. Closing an fstream should clear error state 565 this->clear(); 566 } 567 #endif 568 569 /** 570 * @brief Close the file. 571 * 572 * Calls @c std::basic_filebuf::close(). If that function 573 * fails, @c failbit is set in the stream's error state. 574 */ 575 void 576 close() 577 { 578 if (!_M_filebuf.close()) 579 this->setstate(ios_base::failbit); 580 } 581 }; 582 583 584 // [27.8.1.8] Template class basic_ofstream 585 /** 586 * @brief Controlling output for files. 587 * @ingroup io 588 * 589 * @tparam _CharT Type of character stream. 590 * @tparam _Traits Traits for character type, defaults to 591 * char_traits<_CharT>. 592 * 593 * This class supports reading from named files, using the inherited 594 * functions from std::basic_ostream. To control the associated 595 * sequence, an instance of std::basic_filebuf is used, which this page 596 * refers to as @c sb. 597 */ 598 template<typename _CharT, typename _Traits> 599 class basic_ofstream : public basic_ostream<_CharT,_Traits> 600 { 601 public: 602 // Types: 603 typedef _CharT char_type; 604 typedef _Traits traits_type; 605 typedef typename traits_type::int_type int_type; 606 typedef typename traits_type::pos_type pos_type; 607 typedef typename traits_type::off_type off_type; 608 609 // Non-standard types: 610 typedef basic_filebuf<char_type, traits_type> __filebuf_type; 611 typedef basic_ostream<char_type, traits_type> __ostream_type; 612 613 private: 614 __filebuf_type _M_filebuf; 615 616 public: 617 // Constructors: 618 /** 619 * @brief Default constructor. 620 * 621 * Initializes @c sb using its default constructor, and passes 622 * @c &sb to the base class initializer. Does not open any files 623 * (you haven't given it a filename to open). 624 */ 625 basic_ofstream(): __ostream_type(), _M_filebuf() 626 { this->init(&_M_filebuf); } 627 628 /** 629 * @brief Create an output file stream. 630 * @param __s Null terminated string specifying the filename. 631 * @param __mode Open file in specified mode (see std::ios_base). 632 * 633 * @c ios_base::out | @c ios_base::trunc is automatically included in 634 * @a __mode. 635 * 636 * Tip: When using std::string to hold the filename, you must use 637 * .c_str() before passing it to this constructor. 638 */ 639 explicit 640 basic_ofstream(const char* __s, 641 ios_base::openmode __mode = ios_base::out|ios_base::trunc) 642 : __ostream_type(), _M_filebuf() 643 { 644 this->init(&_M_filebuf); 645 this->open(__s, __mode); 646 } 647 648 #if __cplusplus >= 201103L 649 /** 650 * @brief Create an output file stream. 651 * @param __s std::string specifying the filename. 652 * @param __mode Open file in specified mode (see std::ios_base). 653 * 654 * @c ios_base::out | @c ios_base::trunc is automatically included in 655 * @a __mode. 656 */ 657 explicit 658 basic_ofstream(const std::string& __s, 659 ios_base::openmode __mode = ios_base::out|ios_base::trunc) 660 : __ostream_type(), _M_filebuf() 661 { 662 this->init(&_M_filebuf); 663 this->open(__s, __mode); 664 } 665 #endif 666 667 /** 668 * @brief The destructor does nothing. 669 * 670 * The file is closed by the filebuf object, not the formatting 671 * stream. 672 */ 673 ~basic_ofstream() 674 { } 675 676 // Members: 677 /** 678 * @brief Accessing the underlying buffer. 679 * @return The current basic_filebuf buffer. 680 * 681 * This hides both signatures of std::basic_ios::rdbuf(). 682 */ 683 __filebuf_type* 684 rdbuf() const 685 { return const_cast<__filebuf_type*>(&_M_filebuf); } 686 687 /** 688 * @brief Wrapper to test for an open file. 689 * @return @c rdbuf()->is_open() 690 */ 691 bool 692 is_open() 693 { return _M_filebuf.is_open(); } 694 695 // _GLIBCXX_RESOLVE_LIB_DEFECTS 696 // 365. Lack of const-qualification in clause 27 697 bool 698 is_open() const 699 { return _M_filebuf.is_open(); } 700 701 /** 702 * @brief Opens an external file. 703 * @param __s The name of the file. 704 * @param __mode The open mode flags. 705 * 706 * Calls @c std::basic_filebuf::open(__s,__mode|out|trunc). If that 707 * function fails, @c failbit is set in the stream's error state. 708 * 709 * Tip: When using std::string to hold the filename, you must use 710 * .c_str() before passing it to this constructor. 711 */ 712 void 713 open(const char* __s, 714 ios_base::openmode __mode = ios_base::out | ios_base::trunc) 715 { 716 if (!_M_filebuf.open(__s, __mode | ios_base::out)) 717 this->setstate(ios_base::failbit); 718 else 719 // _GLIBCXX_RESOLVE_LIB_DEFECTS 720 // 409. Closing an fstream should clear error state 721 this->clear(); 722 } 723 724 #if __cplusplus >= 201103L 725 /** 726 * @brief Opens an external file. 727 * @param __s The name of the file. 728 * @param __mode The open mode flags. 729 * 730 * Calls @c std::basic_filebuf::open(s,mode|out|trunc). If that 731 * function fails, @c failbit is set in the stream's error state. 732 */ 733 void 734 open(const std::string& __s, 735 ios_base::openmode __mode = ios_base::out | ios_base::trunc) 736 { 737 if (!_M_filebuf.open(__s, __mode | ios_base::out)) 738 this->setstate(ios_base::failbit); 739 else 740 // _GLIBCXX_RESOLVE_LIB_DEFECTS 741 // 409. Closing an fstream should clear error state 742 this->clear(); 743 } 744 #endif 745 746 /** 747 * @brief Close the file. 748 * 749 * Calls @c std::basic_filebuf::close(). If that function 750 * fails, @c failbit is set in the stream's error state. 751 */ 752 void 753 close() 754 { 755 if (!_M_filebuf.close()) 756 this->setstate(ios_base::failbit); 757 } 758 }; 759 760 761 // [27.8.1.11] Template class basic_fstream 762 /** 763 * @brief Controlling input and output for files. 764 * @ingroup io 765 * 766 * @tparam _CharT Type of character stream. 767 * @tparam _Traits Traits for character type, defaults to 768 * char_traits<_CharT>. 769 * 770 * This class supports reading from and writing to named files, using 771 * the inherited functions from std::basic_iostream. To control the 772 * associated sequence, an instance of std::basic_filebuf is used, which 773 * this page refers to as @c sb. 774 */ 775 template<typename _CharT, typename _Traits> 776 class basic_fstream : public basic_iostream<_CharT, _Traits> 777 { 778 public: 779 // Types: 780 typedef _CharT char_type; 781 typedef _Traits traits_type; 782 typedef typename traits_type::int_type int_type; 783 typedef typename traits_type::pos_type pos_type; 784 typedef typename traits_type::off_type off_type; 785 786 // Non-standard types: 787 typedef basic_filebuf<char_type, traits_type> __filebuf_type; 788 typedef basic_ios<char_type, traits_type> __ios_type; 789 typedef basic_iostream<char_type, traits_type> __iostream_type; 790 791 private: 792 __filebuf_type _M_filebuf; 793 794 public: 795 // Constructors/destructor: 796 /** 797 * @brief Default constructor. 798 * 799 * Initializes @c sb using its default constructor, and passes 800 * @c &sb to the base class initializer. Does not open any files 801 * (you haven't given it a filename to open). 802 */ 803 basic_fstream() 804 : __iostream_type(), _M_filebuf() 805 { this->init(&_M_filebuf); } 806 807 /** 808 * @brief Create an input/output file stream. 809 * @param __s Null terminated string specifying the filename. 810 * @param __mode Open file in specified mode (see std::ios_base). 811 * 812 * Tip: When using std::string to hold the filename, you must use 813 * .c_str() before passing it to this constructor. 814 */ 815 explicit 816 basic_fstream(const char* __s, 817 ios_base::openmode __mode = ios_base::in | ios_base::out) 818 : __iostream_type(0), _M_filebuf() 819 { 820 this->init(&_M_filebuf); 821 this->open(__s, __mode); 822 } 823 824 #if __cplusplus >= 201103L 825 /** 826 * @brief Create an input/output file stream. 827 * @param __s Null terminated string specifying the filename. 828 * @param __mode Open file in specified mode (see std::ios_base). 829 */ 830 explicit 831 basic_fstream(const std::string& __s, 832 ios_base::openmode __mode = ios_base::in | ios_base::out) 833 : __iostream_type(0), _M_filebuf() 834 { 835 this->init(&_M_filebuf); 836 this->open(__s, __mode); 837 } 838 #endif 839 840 /** 841 * @brief The destructor does nothing. 842 * 843 * The file is closed by the filebuf object, not the formatting 844 * stream. 845 */ 846 ~basic_fstream() 847 { } 848 849 // Members: 850 /** 851 * @brief Accessing the underlying buffer. 852 * @return The current basic_filebuf buffer. 853 * 854 * This hides both signatures of std::basic_ios::rdbuf(). 855 */ 856 __filebuf_type* 857 rdbuf() const 858 { return const_cast<__filebuf_type*>(&_M_filebuf); } 859 860 /** 861 * @brief Wrapper to test for an open file. 862 * @return @c rdbuf()->is_open() 863 */ 864 bool 865 is_open() 866 { return _M_filebuf.is_open(); } 867 868 // _GLIBCXX_RESOLVE_LIB_DEFECTS 869 // 365. Lack of const-qualification in clause 27 870 bool 871 is_open() const 872 { return _M_filebuf.is_open(); } 873 874 /** 875 * @brief Opens an external file. 876 * @param __s The name of the file. 877 * @param __mode The open mode flags. 878 * 879 * Calls @c std::basic_filebuf::open(__s,__mode). If that 880 * function fails, @c failbit is set in the stream's error state. 881 * 882 * Tip: When using std::string to hold the filename, you must use 883 * .c_str() before passing it to this constructor. 884 */ 885 void 886 open(const char* __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 } 896 897 #if __cplusplus >= 201103L 898 /** 899 * @brief Opens an external file. 900 * @param __s The name of the file. 901 * @param __mode The open mode flags. 902 * 903 * Calls @c std::basic_filebuf::open(__s,__mode). If that 904 * function fails, @c failbit is set in the stream's error state. 905 */ 906 void 907 open(const std::string& __s, 908 ios_base::openmode __mode = ios_base::in | ios_base::out) 909 { 910 if (!_M_filebuf.open(__s, __mode)) 911 this->setstate(ios_base::failbit); 912 else 913 // _GLIBCXX_RESOLVE_LIB_DEFECTS 914 // 409. Closing an fstream should clear error state 915 this->clear(); 916 } 917 #endif 918 919 /** 920 * @brief Close the file. 921 * 922 * Calls @c std::basic_filebuf::close(). If that function 923 * fails, @c failbit is set in the stream's error state. 924 */ 925 void 926 close() 927 { 928 if (!_M_filebuf.close()) 929 this->setstate(ios_base::failbit); 930 } 931 }; 932 933 _GLIBCXX_END_NAMESPACE_VERSION 934 } // namespace 935 936 #include <bits/fstream.tcc> 937 938 #endif /* _GLIBCXX_FSTREAM */ 939
