1 // File based streams -*- C++ -*- 2 3 // Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 4 // 2006, 2007, 2008, 2009, 2010, 2011 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 include/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 namespace std _GLIBCXX_VISIBILITY(default) 50 { 51 _GLIBCXX_BEGIN_NAMESPACE_VERSION 52 53 // [27.8.1.1] template class basic_filebuf 54 /** 55 * @brief The actual work of input and output (for files). 56 * @ingroup io 57 * 58 * This class associates both its input and output sequence with an 59 * external disk file, and maintains a joint file position for both 60 * sequences. Many of its semantics are described in terms of similar 61 * behavior in the Standard C Library's @c FILE streams. 62 */ 63 // Requirements on traits_type, specific to this class: 64 // traits_type::pos_type must be fpos<traits_type::state_type> 65 // traits_type::off_type must be streamoff 66 // traits_type::state_type must be Assignable and DefaultConstructible, 67 // and traits_type::state_type() must be the initial state for codecvt. 68 template<typename _CharT, typename _Traits> 69 class basic_filebuf : public basic_streambuf<_CharT, _Traits> 70 { 71 public: 72 // Types: 73 typedef _CharT char_type; 74 typedef _Traits traits_type; 75 typedef typename traits_type::int_type int_type; 76 typedef typename traits_type::pos_type pos_type; 77 typedef typename traits_type::off_type off_type; 78 79 typedef basic_streambuf<char_type, traits_type> __streambuf_type; 80 typedef basic_filebuf<char_type, traits_type> __filebuf_type; 81 typedef __basic_file<char> __file_type; 82 typedef typename traits_type::state_type __state_type; 83 typedef codecvt<char_type, char, __state_type> __codecvt_type; 84 85 friend class ios_base; // For sync_with_stdio. 86 87 protected: 88 // Data Members: 89 // MT lock inherited from libio or other low-level io library. 90 __c_lock _M_lock; 91 92 // External buffer. 93 __file_type _M_file; 94 95 /// Place to stash in || out || in | out settings for current filebuf. 96 ios_base::openmode _M_mode; 97 98 // Beginning state type for codecvt. 99 __state_type _M_state_beg; 100 101 // During output, the state that corresponds to pptr(), 102 // during input, the state that corresponds to egptr() and 103 // _M_ext_next. 104 __state_type _M_state_cur; 105 106 // Not used for output. During input, the state that corresponds 107 // to eback() and _M_ext_buf. 108 __state_type _M_state_last; 109 110 /// Pointer to the beginning of internal buffer. 111 char_type* _M_buf; 112 113 /** 114 * Actual size of internal buffer. This number is equal to the size 115 * of the put area + 1 position, reserved for the overflow char of 116 * a full area. 117 */ 118 size_t _M_buf_size; 119 120 // Set iff _M_buf is allocated memory from _M_allocate_internal_buffer. 121 bool _M_buf_allocated; 122 123 /** 124 * _M_reading == false && _M_writing == false for @b uncommitted mode; 125 * _M_reading == true for @b read mode; 126 * _M_writing == true for @b write mode; 127 * 128 * NB: _M_reading == true && _M_writing == true is unused. 129 */ 130 bool _M_reading; 131 bool _M_writing; 132 133 //@{ 134 /** 135 * Necessary bits for putback buffer management. 136 * 137 * @note pbacks of over one character are not currently supported. 138 */ 139 char_type _M_pback; 140 char_type* _M_pback_cur_save; 141 char_type* _M_pback_end_save; 142 bool _M_pback_init; 143 //@} 144 145 // Cached codecvt facet. 146 const __codecvt_type* _M_codecvt; 147 148 /** 149 * Buffer for external characters. Used for input when 150 * codecvt::always_noconv() == false. When valid, this corresponds 151 * to eback(). 152 */ 153 char* _M_ext_buf; 154 155 /** 156 * Size of buffer held by _M_ext_buf. 157 */ 158 streamsize _M_ext_buf_size; 159 160 /** 161 * Pointers into the buffer held by _M_ext_buf that delimit a 162 * subsequence of bytes that have been read but not yet converted. 163 * When valid, _M_ext_next corresponds to egptr(). 164 */ 165 const char* _M_ext_next; 166 char* _M_ext_end; 167 168 /** 169 * Initializes pback buffers, and moves normal buffers to safety. 170 * Assumptions: 171 * _M_in_cur has already been moved back 172 */ 173 void 174 _M_create_pback() 175 { 176 if (!_M_pback_init) 177 { 178 _M_pback_cur_save = this->gptr(); 179 _M_pback_end_save = this->egptr(); 180 this->setg(&_M_pback, &_M_pback, &_M_pback + 1); 181 _M_pback_init = true; 182 } 183 } 184 185 /** 186 * Deactivates pback buffer contents, and restores normal buffer. 187 * Assumptions: 188 * The pback buffer has only moved forward. 189 */ 190 void 191 _M_destroy_pback() throw() 192 { 193 if (_M_pback_init) 194 { 195 // Length _M_in_cur moved in the pback buffer. 196 _M_pback_cur_save += this->gptr() != this->eback(); 197 this->setg(_M_buf, _M_pback_cur_save, _M_pback_end_save); 198 _M_pback_init = false; 199 } 200 } 201 202 public: 203 // Constructors/destructor: 204 /** 205 * @brief Does not open any files. 206 * 207 * The default constructor initializes the parent class using its 208 * own default ctor. 209 */ 210 basic_filebuf(); 211 212 /** 213 * @brief The destructor closes the file first. 214 */ 215 virtual 216 ~basic_filebuf() 217 { this->close(); } 218 219 // Members: 220 /** 221 * @brief Returns true if the external file is open. 222 */ 223 bool 224 is_open() const throw() 225 { return _M_file.is_open(); } 226 227 /** 228 * @brief Opens an external file. 229 * @param __s The name of the file. 230 * @param __mode The open mode flags. 231 * @return @c this on success, NULL on failure 232 * 233 * If a file is already open, this function immediately fails. 234 * Otherwise it tries to open the file named @a __s using the flags 235 * given in @a mode. 236 * 237 * Table 92, adapted here, gives the relation between openmode 238 * combinations and the equivalent fopen() flags. 239 * (NB: lines app, in|out|app, in|app, binary|app, binary|in|out|app, 240 * and binary|in|app per DR 596) 241 * +---------------------------------------------------------+ 242 * | ios_base Flag combination stdio equivalent | 243 * |binary in out trunc app | 244 * +---------------------------------------------------------+ 245 * | + w | 246 * | + + a | 247 * | + a | 248 * | + + w | 249 * | + r | 250 * | + + r+ | 251 * | + + + w+ | 252 * | + + + a+ | 253 * | + + a+ | 254 * +---------------------------------------------------------+ 255 * | + + wb | 256 * | + + + ab | 257 * | + + ab | 258 * | + + + wb | 259 * | + + rb | 260 * | + + + r+b | 261 * | + + + + w+b | 262 * | + + + + a+b | 263 * | + + + a+b | 264 * +---------------------------------------------------------+ 265 */ 266 __filebuf_type* 267 open(const char* __s, ios_base::openmode __mode); 268 269 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 270 /** 271 * @brief Opens an external file. 272 * @param __s The name of the file. 273 * @param __mode The open mode flags. 274 * @return @c this on success, NULL on failure 275 */ 276 __filebuf_type* 277 open(const std::string& __s, ios_base::openmode __mode) 278 { return open(__s.c_str(), __mode); } 279 #endif 280 281 /** 282 * @brief Closes the currently associated file. 283 * @return @c this on success, NULL on failure 284 * 285 * If no file is currently open, this function immediately fails. 286 * 287 * If a <em>put buffer area</em> exists, @c overflow(eof) is 288 * called to flush all the characters. The file is then 289 * closed. 290 * 291 * If any operations fail, this function also fails. 292 */ 293 __filebuf_type* 294 close(); 295 296 protected: 297 void 298 _M_allocate_internal_buffer(); 299 300 void 301 _M_destroy_internal_buffer() throw(); 302 303 // [27.8.1.4] overridden virtual functions 304 virtual streamsize 305 showmanyc(); 306 307 // Stroustrup, 1998, p. 628 308 // underflow() and uflow() functions are called to get the next 309 // character from the real input source when the buffer is empty. 310 // Buffered input uses underflow() 311 312 virtual int_type 313 underflow(); 314 315 virtual int_type 316 pbackfail(int_type __c = _Traits::eof()); 317 318 // Stroustrup, 1998, p 648 319 // The overflow() function is called to transfer characters to the 320 // real output destination when the buffer is full. A call to 321 // overflow(c) outputs the contents of the buffer plus the 322 // character c. 323 // 27.5.2.4.5 324 // Consume some sequence of the characters in the pending sequence. 325 virtual int_type 326 overflow(int_type __c = _Traits::eof()); 327 328 // Convert internal byte sequence to external, char-based 329 // sequence via codecvt. 330 bool 331 _M_convert_to_external(char_type*, streamsize); 332 333 /** 334 * @brief Manipulates the buffer. 335 * @param __s Pointer to a buffer area. 336 * @param __n Size of @a __s. 337 * @return @c this 338 * 339 * If no file has been opened, and both @a __s and @a __n are zero, then 340 * the stream becomes unbuffered. Otherwise, @c __s is used as a 341 * buffer; see 342 * http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt11ch25s02.html 343 * for more. 344 */ 345 virtual __streambuf_type* 346 setbuf(char_type* __s, streamsize __n); 347 348 virtual pos_type 349 seekoff(off_type __off, ios_base::seekdir __way, 350 ios_base::openmode __mode = ios_base::in | ios_base::out); 351 352 virtual pos_type 353 seekpos(pos_type __pos, 354 ios_base::openmode __mode = ios_base::in | ios_base::out); 355 356 // Common code for seekoff, seekpos, and overflow 357 pos_type 358 _M_seek(off_type __off, ios_base::seekdir __way, __state_type __state); 359 360 int 361 _M_get_ext_pos(__state_type &__state); 362 363 virtual int 364 sync(); 365 366 virtual void 367 imbue(const locale& __loc); 368 369 virtual streamsize 370 xsgetn(char_type* __s, streamsize __n); 371 372 virtual streamsize 373 xsputn(const char_type* __s, streamsize __n); 374 375 // Flushes output buffer, then writes unshift sequence. 376 bool 377 _M_terminate_output(); 378 379 /** 380 * This function sets the pointers of the internal buffer, both get 381 * and put areas. Typically: 382 * 383 * __off == egptr() - eback() upon underflow/uflow (@b read mode); 384 * __off == 0 upon overflow (@b write mode); 385 * __off == -1 upon open, setbuf, seekoff/pos (@b uncommitted mode). 386 * 387 * NB: epptr() - pbase() == _M_buf_size - 1, since _M_buf_size 388 * reflects the actual allocated memory and the last cell is reserved 389 * for the overflow char of a full put area. 390 */ 391 void 392 _M_set_buffer(streamsize __off) 393 { 394 const bool __testin = _M_mode & ios_base::in; 395 const bool __testout = _M_mode & ios_base::out; 396 397 if (__testin && __off > 0) 398 this->setg(_M_buf, _M_buf, _M_buf + __off); 399 else 400 this->setg(_M_buf, _M_buf, _M_buf); 401 402 if (__testout && __off == 0 && _M_buf_size > 1 ) 403 this->setp(_M_buf, _M_buf + _M_buf_size - 1); 404 else 405 this->setp(0, 0); 406 } 407 }; 408 409 // [27.8.1.5] Template class basic_ifstream 410 /** 411 * @brief Controlling input for files. 412 * @ingroup io 413 * 414 * This class supports reading from named files, using the inherited 415 * functions from std::basic_istream. To control the associated 416 * sequence, an instance of std::basic_filebuf is used, which this page 417 * refers to as @c sb. 418 */ 419 template<typename _CharT, typename _Traits> 420 class basic_ifstream : public basic_istream<_CharT, _Traits> 421 { 422 public: 423 // Types: 424 typedef _CharT char_type; 425 typedef _Traits traits_type; 426 typedef typename traits_type::int_type int_type; 427 typedef typename traits_type::pos_type pos_type; 428 typedef typename traits_type::off_type off_type; 429 430 // Non-standard types: 431 typedef basic_filebuf<char_type, traits_type> __filebuf_type; 432 typedef basic_istream<char_type, traits_type> __istream_type; 433 434 private: 435 __filebuf_type _M_filebuf; 436 437 public: 438 // Constructors/Destructors: 439 /** 440 * @brief Default constructor. 441 * 442 * Initializes @c sb using its default constructor, and passes 443 * @c &sb to the base class initializer. Does not open any files 444 * (you haven't given it a filename to open). 445 */ 446 basic_ifstream() : __istream_type(), _M_filebuf() 447 { this->init(&_M_filebuf); } 448 449 /** 450 * @brief Create an input file stream. 451 * @param __s Null terminated string specifying the filename. 452 * @param __mode Open file in specified mode (see std::ios_base). 453 * 454 * @c ios_base::in is automatically included in @a __mode. 455 * 456 * Tip: When using std::string to hold the filename, you must use 457 * .c_str() before passing it to this constructor. 458 */ 459 explicit 460 basic_ifstream(const char* __s, ios_base::openmode __mode = ios_base::in) 461 : __istream_type(), _M_filebuf() 462 { 463 this->init(&_M_filebuf); 464 this->open(__s, __mode); 465 } 466 467 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 468 /** 469 * @brief Create an input file stream. 470 * @param __s std::string specifying the filename. 471 * @param __mode Open file in specified mode (see std::ios_base). 472 * 473 * @c ios_base::in is automatically included in @a __mode. 474 */ 475 explicit 476 basic_ifstream(const std::string& __s, 477 ios_base::openmode __mode = ios_base::in) 478 : __istream_type(), _M_filebuf() 479 { 480 this->init(&_M_filebuf); 481 this->open(__s, __mode); 482 } 483 #endif 484 485 /** 486 * @brief The destructor does nothing. 487 * 488 * The file is closed by the filebuf object, not the formatting 489 * stream. 490 */ 491 ~basic_ifstream() 492 { } 493 494 // Members: 495 /** 496 * @brief Accessing the underlying buffer. 497 * @return The current basic_filebuf buffer. 498 * 499 * This hides both signatures of std::basic_ios::rdbuf(). 500 */ 501 __filebuf_type* 502 rdbuf() const 503 { return const_cast<__filebuf_type*>(&_M_filebuf); } 504 505 /** 506 * @brief Wrapper to test for an open file. 507 * @return @c rdbuf()->is_open() 508 */ 509 bool 510 is_open() 511 { return _M_filebuf.is_open(); } 512 513 // _GLIBCXX_RESOLVE_LIB_DEFECTS 514 // 365. Lack of const-qualification in clause 27 515 bool 516 is_open() const 517 { return _M_filebuf.is_open(); } 518 519 /** 520 * @brief Opens an external file. 521 * @param __s The name of the file. 522 * @param __mode The open mode flags. 523 * 524 * Calls @c std::basic_filebuf::open(s,__mode|in). If that function 525 * fails, @c failbit is set in the stream's error state. 526 * 527 * Tip: When using std::string to hold the filename, you must use 528 * .c_str() before passing it to this constructor. 529 */ 530 void 531 open(const char* __s, ios_base::openmode __mode = ios_base::in) 532 { 533 if (!_M_filebuf.open(__s, __mode | ios_base::in)) 534 this->setstate(ios_base::failbit); 535 else 536 // _GLIBCXX_RESOLVE_LIB_DEFECTS 537 // 409. Closing an fstream should clear error state 538 this->clear(); 539 } 540 541 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 542 /** 543 * @brief Opens an external file. 544 * @param __s The name of the file. 545 * @param __mode The open mode flags. 546 * 547 * Calls @c std::basic_filebuf::open(__s,__mode|in). If that function 548 * fails, @c failbit is set in the stream's error state. 549 */ 550 void 551 open(const std::string& __s, ios_base::openmode __mode = ios_base::in) 552 { 553 if (!_M_filebuf.open(__s, __mode | ios_base::in)) 554 this->setstate(ios_base::failbit); 555 else 556 // _GLIBCXX_RESOLVE_LIB_DEFECTS 557 // 409. Closing an fstream should clear error state 558 this->clear(); 559 } 560 #endif 561 562 /** 563 * @brief Close the file. 564 * 565 * Calls @c std::basic_filebuf::close(). If that function 566 * fails, @c failbit is set in the stream's error state. 567 */ 568 void 569 close() 570 { 571 if (!_M_filebuf.close()) 572 this->setstate(ios_base::failbit); 573 } 574 }; 575 576 577 // [27.8.1.8] Template class basic_ofstream 578 /** 579 * @brief Controlling output for files. 580 * @ingroup io 581 * 582 * This class supports reading from named files, using the inherited 583 * functions from std::basic_ostream. To control the associated 584 * sequence, an instance of std::basic_filebuf is used, which this page 585 * refers to as @c sb. 586 */ 587 template<typename _CharT, typename _Traits> 588 class basic_ofstream : public basic_ostream<_CharT,_Traits> 589 { 590 public: 591 // Types: 592 typedef _CharT char_type; 593 typedef _Traits traits_type; 594 typedef typename traits_type::int_type int_type; 595 typedef typename traits_type::pos_type pos_type; 596 typedef typename traits_type::off_type off_type; 597 598 // Non-standard types: 599 typedef basic_filebuf<char_type, traits_type> __filebuf_type; 600 typedef basic_ostream<char_type, traits_type> __ostream_type; 601 602 private: 603 __filebuf_type _M_filebuf; 604 605 public: 606 // Constructors: 607 /** 608 * @brief Default constructor. 609 * 610 * Initializes @c sb using its default constructor, and passes 611 * @c &sb to the base class initializer. Does not open any files 612 * (you haven't given it a filename to open). 613 */ 614 basic_ofstream(): __ostream_type(), _M_filebuf() 615 { this->init(&_M_filebuf); } 616 617 /** 618 * @brief Create an output file stream. 619 * @param __s Null terminated string specifying the filename. 620 * @param __mode Open file in specified mode (see std::ios_base). 621 * 622 * @c ios_base::out|ios_base::trunc is automatically included in 623 * @p __mode. 624 * 625 * Tip: When using std::string to hold the filename, you must use 626 * .c_str() before passing it to this constructor. 627 */ 628 explicit 629 basic_ofstream(const char* __s, 630 ios_base::openmode __mode = ios_base::out|ios_base::trunc) 631 : __ostream_type(), _M_filebuf() 632 { 633 this->init(&_M_filebuf); 634 this->open(__s, __mode); 635 } 636 637 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 638 /** 639 * @brief Create an output file stream. 640 * @param __s std::string specifying the filename. 641 * @param __mode Open file in specified mode (see std::ios_base). 642 * 643 * @c ios_base::out|ios_base::trunc is automatically included in 644 * @a __mode. 645 */ 646 explicit 647 basic_ofstream(const std::string& __s, 648 ios_base::openmode __mode = ios_base::out|ios_base::trunc) 649 : __ostream_type(), _M_filebuf() 650 { 651 this->init(&_M_filebuf); 652 this->open(__s, __mode); 653 } 654 #endif 655 656 /** 657 * @brief The destructor does nothing. 658 * 659 * The file is closed by the filebuf object, not the formatting 660 * stream. 661 */ 662 ~basic_ofstream() 663 { } 664 665 // Members: 666 /** 667 * @brief Accessing the underlying buffer. 668 * @return The current basic_filebuf buffer. 669 * 670 * This hides both signatures of std::basic_ios::rdbuf(). 671 */ 672 __filebuf_type* 673 rdbuf() const 674 { return const_cast<__filebuf_type*>(&_M_filebuf); } 675 676 /** 677 * @brief Wrapper to test for an open file. 678 * @return @c rdbuf()->is_open() 679 */ 680 bool 681 is_open() 682 { return _M_filebuf.is_open(); } 683 684 // _GLIBCXX_RESOLVE_LIB_DEFECTS 685 // 365. Lack of const-qualification in clause 27 686 bool 687 is_open() const 688 { return _M_filebuf.is_open(); } 689 690 /** 691 * @brief Opens an external file. 692 * @param __s The name of the file. 693 * @param __mode The open mode flags. 694 * 695 * Calls @c std::basic_filebuf::open(__s,__mode|out|trunc). If that 696 * function fails, @c failbit is set in the stream's error state. 697 * 698 * Tip: When using std::string to hold the filename, you must use 699 * .c_str() before passing it to this constructor. 700 */ 701 void 702 open(const char* __s, 703 ios_base::openmode __mode = ios_base::out | ios_base::trunc) 704 { 705 if (!_M_filebuf.open(__s, __mode | ios_base::out)) 706 this->setstate(ios_base::failbit); 707 else 708 // _GLIBCXX_RESOLVE_LIB_DEFECTS 709 // 409. Closing an fstream should clear error state 710 this->clear(); 711 } 712 713 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 714 /** 715 * @brief Opens an external file. 716 * @param __s The name of the file. 717 * @param __mode The open mode flags. 718 * 719 * Calls @c std::basic_filebuf::open(s,mode|out|trunc). If that 720 * function fails, @c failbit is set in the stream's error state. 721 */ 722 void 723 open(const std::string& __s, 724 ios_base::openmode __mode = ios_base::out | ios_base::trunc) 725 { 726 if (!_M_filebuf.open(__s, __mode | ios_base::out)) 727 this->setstate(ios_base::failbit); 728 else 729 // _GLIBCXX_RESOLVE_LIB_DEFECTS 730 // 409. Closing an fstream should clear error state 731 this->clear(); 732 } 733 #endif 734 735 /** 736 * @brief Close the file. 737 * 738 * Calls @c std::basic_filebuf::close(). If that function 739 * fails, @c failbit is set in the stream's error state. 740 */ 741 void 742 close() 743 { 744 if (!_M_filebuf.close()) 745 this->setstate(ios_base::failbit); 746 } 747 }; 748 749 750 // [27.8.1.11] Template class basic_fstream 751 /** 752 * @brief Controlling input and output for files. 753 * @ingroup io 754 * 755 * This class supports reading from and writing to named files, using 756 * the inherited functions from std::basic_iostream. To control the 757 * associated sequence, an instance of std::basic_filebuf is used, which 758 * this page refers to as @c sb. 759 */ 760 template<typename _CharT, typename _Traits> 761 class basic_fstream : public basic_iostream<_CharT, _Traits> 762 { 763 public: 764 // Types: 765 typedef _CharT char_type; 766 typedef _Traits traits_type; 767 typedef typename traits_type::int_type int_type; 768 typedef typename traits_type::pos_type pos_type; 769 typedef typename traits_type::off_type off_type; 770 771 // Non-standard types: 772 typedef basic_filebuf<char_type, traits_type> __filebuf_type; 773 typedef basic_ios<char_type, traits_type> __ios_type; 774 typedef basic_iostream<char_type, traits_type> __iostream_type; 775 776 private: 777 __filebuf_type _M_filebuf; 778 779 public: 780 // Constructors/destructor: 781 /** 782 * @brief Default constructor. 783 * 784 * Initializes @c sb using its default constructor, and passes 785 * @c &sb to the base class initializer. Does not open any files 786 * (you haven't given it a filename to open). 787 */ 788 basic_fstream() 789 : __iostream_type(), _M_filebuf() 790 { this->init(&_M_filebuf); } 791 792 /** 793 * @brief Create an input/output file stream. 794 * @param __s Null terminated string specifying the filename. 795 * @param __mode Open file in specified mode (see std::ios_base). 796 * 797 * Tip: When using std::string to hold the filename, you must use 798 * .c_str() before passing it to this constructor. 799 */ 800 explicit 801 basic_fstream(const char* __s, 802 ios_base::openmode __mode = ios_base::in | ios_base::out) 803 : __iostream_type(0), _M_filebuf() 804 { 805 this->init(&_M_filebuf); 806 this->open(__s, __mode); 807 } 808 809 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 810 /** 811 * @brief Create an input/output file stream. 812 * @param __s Null terminated string specifying the filename. 813 * @param __mode Open file in specified mode (see std::ios_base). 814 */ 815 explicit 816 basic_fstream(const std::string& __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 #endif 824 825 /** 826 * @brief The destructor does nothing. 827 * 828 * The file is closed by the filebuf object, not the formatting 829 * stream. 830 */ 831 ~basic_fstream() 832 { } 833 834 // Members: 835 /** 836 * @brief Accessing the underlying buffer. 837 * @return The current basic_filebuf buffer. 838 * 839 * This hides both signatures of std::basic_ios::rdbuf(). 840 */ 841 __filebuf_type* 842 rdbuf() const 843 { return const_cast<__filebuf_type*>(&_M_filebuf); } 844 845 /** 846 * @brief Wrapper to test for an open file. 847 * @return @c rdbuf()->is_open() 848 */ 849 bool 850 is_open() 851 { return _M_filebuf.is_open(); } 852 853 // _GLIBCXX_RESOLVE_LIB_DEFECTS 854 // 365. Lack of const-qualification in clause 27 855 bool 856 is_open() const 857 { return _M_filebuf.is_open(); } 858 859 /** 860 * @brief Opens an external file. 861 * @param __s The name of the file. 862 * @param __mode The open mode flags. 863 * 864 * Calls @c std::basic_filebuf::open(__s,__mode). If that 865 * function fails, @c failbit is set in the stream's error state. 866 * 867 * Tip: When using std::string to hold the filename, you must use 868 * .c_str() before passing it to this constructor. 869 */ 870 void 871 open(const char* __s, 872 ios_base::openmode __mode = ios_base::in | ios_base::out) 873 { 874 if (!_M_filebuf.open(__s, __mode)) 875 this->setstate(ios_base::failbit); 876 else 877 // _GLIBCXX_RESOLVE_LIB_DEFECTS 878 // 409. Closing an fstream should clear error state 879 this->clear(); 880 } 881 882 #ifdef __GXX_EXPERIMENTAL_CXX0X__ 883 /** 884 * @brief Opens an external file. 885 * @param __s The name of the file. 886 * @param __mode The open mode flags. 887 * 888 * Calls @c std::basic_filebuf::open(__s,__mode). If that 889 * function fails, @c failbit is set in the stream's error state. 890 */ 891 void 892 open(const std::string& __s, 893 ios_base::openmode __mode = ios_base::in | ios_base::out) 894 { 895 if (!_M_filebuf.open(__s, __mode)) 896 this->setstate(ios_base::failbit); 897 else 898 // _GLIBCXX_RESOLVE_LIB_DEFECTS 899 // 409. Closing an fstream should clear error state 900 this->clear(); 901 } 902 #endif 903 904 /** 905 * @brief Close the file. 906 * 907 * Calls @c std::basic_filebuf::close(). If that function 908 * fails, @c failbit is set in the stream's error state. 909 */ 910 void 911 close() 912 { 913 if (!_M_filebuf.close()) 914 this->setstate(ios_base::failbit); 915 } 916 }; 917 918 _GLIBCXX_END_NAMESPACE_VERSION 919 } // namespace 920 921 #include <bits/fstream.tcc> 922 923 #endif /* _GLIBCXX_FSTREAM */ 924
