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The C and C++ Include Header Files
/usr/include/c++/11/bits/fstream.tcc
$ cat -n /usr/include/c++/11/bits/fstream.tcc 1 // File based streams -*- C++ -*- 2 3 // Copyright (C) 1997-2021 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 bits/fstream.tcc 26 * This is an internal header file, included by other library headers. 27 * Do not attempt to use it directly. @headername{fstream} 28 */ 29 30 // 31 // ISO C++ 14882: 27.8 File-based streams 32 // 33 34 #ifndef _FSTREAM_TCC 35 #define _FSTREAM_TCC 1 36 37 #pragma GCC system_header 38 39 #include <bits/cxxabi_forced.h> 40 #include <bits/move.h> // for swap 41 #include <cerrno> 42 43 namespace std _GLIBCXX_VISIBILITY(default) 44 { 45 _GLIBCXX_BEGIN_NAMESPACE_VERSION 46 47 template<typename _CharT, typename _Traits> 48 void 49 basic_filebuf<_CharT, _Traits>:: 50 _M_allocate_internal_buffer() 51 { 52 // Allocate internal buffer only if one doesn't already exist 53 // (either allocated or provided by the user via setbuf). 54 if (!_M_buf_allocated && !_M_buf) 55 { 56 _M_buf = new char_type[_M_buf_size]; 57 _M_buf_allocated = true; 58 } 59 } 60 61 template<typename _CharT, typename _Traits> 62 void 63 basic_filebuf<_CharT, _Traits>:: 64 _M_destroy_internal_buffer() throw() 65 { 66 if (_M_buf_allocated) 67 { 68 delete [] _M_buf; 69 _M_buf = 0; 70 _M_buf_allocated = false; 71 } 72 delete [] _M_ext_buf; 73 _M_ext_buf = 0; 74 _M_ext_buf_size = 0; 75 _M_ext_next = 0; 76 _M_ext_end = 0; 77 } 78 79 template<typename _CharT, typename _Traits> 80 basic_filebuf<_CharT, _Traits>:: 81 basic_filebuf() : __streambuf_type(), _M_lock(), _M_file(&_M_lock), 82 _M_mode(ios_base::openmode(0)), _M_state_beg(), _M_state_cur(), 83 _M_state_last(), _M_buf(0), _M_buf_size(_GLIBCXX_BUFSIZ), 84 _M_buf_allocated(false), _M_reading(false), _M_writing(false), _M_pback(), 85 _M_pback_cur_save(0), _M_pback_end_save(0), _M_pback_init(false), 86 _M_codecvt(0), _M_ext_buf(0), _M_ext_buf_size(0), _M_ext_next(0), 87 _M_ext_end(0) 88 { 89 if (has_facet<__codecvt_type>(this->_M_buf_locale)) 90 _M_codecvt = &use_facet<__codecvt_type>(this->_M_buf_locale); 91 } 92 93 #if __cplusplus >= 201103L 94 template<typename _CharT, typename _Traits> 95 basic_filebuf<_CharT, _Traits>:: 96 basic_filebuf(basic_filebuf&& __rhs) 97 : __streambuf_type(__rhs), 98 _M_lock(), _M_file(std::move(__rhs._M_file), &_M_lock), 99 _M_mode(std::__exchange(__rhs._M_mode, ios_base::openmode(0))), 100 _M_state_beg(std::move(__rhs._M_state_beg)), 101 _M_state_cur(std::move(__rhs._M_state_cur)), 102 _M_state_last(std::move(__rhs._M_state_last)), 103 _M_buf(std::__exchange(__rhs._M_buf, nullptr)), 104 _M_buf_size(std::__exchange(__rhs._M_buf_size, 1)), 105 _M_buf_allocated(std::__exchange(__rhs._M_buf_allocated, false)), 106 _M_reading(std::__exchange(__rhs._M_reading, false)), 107 _M_writing(std::__exchange(__rhs._M_writing, false)), 108 _M_pback(__rhs._M_pback), 109 _M_pback_cur_save(std::__exchange(__rhs._M_pback_cur_save, nullptr)), 110 _M_pback_end_save(std::__exchange(__rhs._M_pback_end_save, nullptr)), 111 _M_pback_init(std::__exchange(__rhs._M_pback_init, false)), 112 _M_codecvt(__rhs._M_codecvt), 113 _M_ext_buf(std::__exchange(__rhs._M_ext_buf, nullptr)), 114 _M_ext_buf_size(std::__exchange(__rhs._M_ext_buf_size, 0)), 115 _M_ext_next(std::__exchange(__rhs._M_ext_next, nullptr)), 116 _M_ext_end(std::__exchange(__rhs._M_ext_end, nullptr)) 117 { 118 __rhs._M_set_buffer(-1); 119 __rhs._M_state_last = __rhs._M_state_cur = __rhs._M_state_beg; 120 } 121 122 template<typename _CharT, typename _Traits> 123 basic_filebuf<_CharT, _Traits>& 124 basic_filebuf<_CharT, _Traits>:: 125 operator=(basic_filebuf&& __rhs) 126 { 127 this->close(); 128 __streambuf_type::operator=(__rhs); 129 _M_file.swap(__rhs._M_file); 130 _M_mode = std::__exchange(__rhs._M_mode, ios_base::openmode(0)); 131 _M_state_beg = std::move(__rhs._M_state_beg); 132 _M_state_cur = std::move(__rhs._M_state_cur); 133 _M_state_last = std::move(__rhs._M_state_last); 134 _M_buf = std::__exchange(__rhs._M_buf, nullptr); 135 _M_buf_size = std::__exchange(__rhs._M_buf_size, 1); 136 _M_buf_allocated = std::__exchange(__rhs._M_buf_allocated, false); 137 _M_ext_buf = std::__exchange(__rhs._M_ext_buf, nullptr); 138 _M_ext_buf_size = std::__exchange(__rhs._M_ext_buf_size, 0); 139 _M_ext_next = std::__exchange(__rhs._M_ext_next, nullptr); 140 _M_ext_end = std::__exchange(__rhs._M_ext_end, nullptr); 141 _M_reading = std::__exchange(__rhs._M_reading, false); 142 _M_writing = std::__exchange(__rhs._M_writing, false); 143 _M_pback_cur_save = std::__exchange(__rhs._M_pback_cur_save, nullptr); 144 _M_pback_end_save = std::__exchange(__rhs._M_pback_end_save, nullptr); 145 _M_pback_init = std::__exchange(__rhs._M_pback_init, false); 146 __rhs._M_set_buffer(-1); 147 __rhs._M_state_last = __rhs._M_state_cur = __rhs._M_state_beg; 148 return *this; 149 } 150 151 template<typename _CharT, typename _Traits> 152 void 153 basic_filebuf<_CharT, _Traits>:: 154 swap(basic_filebuf& __rhs) 155 { 156 __streambuf_type::swap(__rhs); 157 _M_file.swap(__rhs._M_file); 158 std::swap(_M_mode, __rhs._M_mode); 159 std::swap(_M_state_beg, __rhs._M_state_beg); 160 std::swap(_M_state_cur, __rhs._M_state_cur); 161 std::swap(_M_state_last, __rhs._M_state_last); 162 std::swap(_M_buf, __rhs._M_buf); 163 std::swap(_M_buf_size, __rhs._M_buf_size); 164 std::swap(_M_buf_allocated, __rhs._M_buf_allocated); 165 std::swap(_M_ext_buf, __rhs._M_ext_buf); 166 std::swap(_M_ext_buf_size, __rhs._M_ext_buf_size); 167 std::swap(_M_ext_next, __rhs._M_ext_next); 168 std::swap(_M_ext_end, __rhs._M_ext_end); 169 std::swap(_M_reading, __rhs._M_reading); 170 std::swap(_M_writing, __rhs._M_writing); 171 std::swap(_M_pback_cur_save, __rhs._M_pback_cur_save); 172 std::swap(_M_pback_end_save, __rhs._M_pback_end_save); 173 std::swap(_M_pback_init, __rhs._M_pback_init); 174 } 175 #endif 176 177 template<typename _CharT, typename _Traits> 178 typename basic_filebuf<_CharT, _Traits>::__filebuf_type* 179 basic_filebuf<_CharT, _Traits>:: 180 open(const char* __s, ios_base::openmode __mode) 181 { 182 __filebuf_type *__ret = 0; 183 if (!this->is_open()) 184 { 185 _M_file.open(__s, __mode); 186 if (this->is_open()) 187 { 188 _M_allocate_internal_buffer(); 189 _M_mode = __mode; 190 191 // Setup initial buffer to 'uncommitted' mode. 192 _M_reading = false; 193 _M_writing = false; 194 _M_set_buffer(-1); 195 196 // Reset to initial state. 197 _M_state_last = _M_state_cur = _M_state_beg; 198 199 // 27.8.1.3,4 200 if ((__mode & ios_base::ate) 201 && this->seekoff(0, ios_base::end, __mode) 202 == pos_type(off_type(-1))) 203 this->close(); 204 else 205 __ret = this; 206 } 207 } 208 return __ret; 209 } 210 211 #if _GLIBCXX_HAVE__WFOPEN && _GLIBCXX_USE_WCHAR_T 212 template<typename _CharT, typename _Traits> 213 basic_filebuf<_CharT, _Traits>* 214 basic_filebuf<_CharT, _Traits>:: 215 open(const wchar_t* __s, ios_base::openmode __mode) 216 { 217 __filebuf_type *__ret = 0; 218 if (!this->is_open()) 219 { 220 _M_file.open(__s, __mode); 221 if (this->is_open()) 222 { 223 _M_allocate_internal_buffer(); 224 _M_mode = __mode; 225 226 // Setup initial buffer to 'uncommitted' mode. 227 _M_reading = false; 228 _M_writing = false; 229 _M_set_buffer(-1); 230 231 // Reset to initial state. 232 _M_state_last = _M_state_cur = _M_state_beg; 233 234 // 27.8.1.3,4 235 if ((__mode & ios_base::ate) 236 && this->seekoff(0, ios_base::end, __mode) 237 == pos_type(off_type(-1))) 238 this->close(); 239 else 240 __ret = this; 241 } 242 } 243 return __ret; 244 } 245 #endif // HAVE__WFOPEN && USE_WCHAR_T 246 247 template<typename _CharT, typename _Traits> 248 typename basic_filebuf<_CharT, _Traits>::__filebuf_type* 249 basic_filebuf<_CharT, _Traits>:: 250 close() 251 { 252 if (!this->is_open()) 253 return 0; 254 255 bool __testfail = false; 256 { 257 // NB: Do this here so that re-opened filebufs will be cool... 258 struct __close_sentry 259 { 260 basic_filebuf *__fb; 261 __close_sentry (basic_filebuf *__fbi): __fb(__fbi) { } 262 ~__close_sentry () 263 { 264 __fb->_M_mode = ios_base::openmode(0); 265 __fb->_M_pback_init = false; 266 __fb->_M_destroy_internal_buffer(); 267 __fb->_M_reading = false; 268 __fb->_M_writing = false; 269 __fb->_M_set_buffer(-1); 270 __fb->_M_state_last = __fb->_M_state_cur = __fb->_M_state_beg; 271 } 272 } __cs (this); 273 274 __try 275 { 276 if (!_M_terminate_output()) 277 __testfail = true; 278 } 279 __catch(...) 280 { 281 _M_file.close(); 282 __throw_exception_again; 283 } 284 } 285 286 if (!_M_file.close()) 287 __testfail = true; 288 289 if (__testfail) 290 return 0; 291 else 292 return this; 293 } 294 295 template<typename _CharT, typename _Traits> 296 streamsize 297 basic_filebuf<_CharT, _Traits>:: 298 showmanyc() 299 { 300 streamsize __ret = -1; 301 const bool __testin = _M_mode & ios_base::in; 302 if (__testin && this->is_open()) 303 { 304 // For a stateful encoding (-1) the pending sequence might be just 305 // shift and unshift prefixes with no actual character. 306 __ret = this->egptr() - this->gptr(); 307 308 #if _GLIBCXX_HAVE_DOS_BASED_FILESYSTEM 309 // About this workaround, see libstdc++/20806. 310 const bool __testbinary = _M_mode & ios_base::binary; 311 if (__check_facet(_M_codecvt).encoding() >= 0 312 && __testbinary) 313 #else 314 if (__check_facet(_M_codecvt).encoding() >= 0) 315 #endif 316 __ret += _M_file.showmanyc() / _M_codecvt->max_length(); 317 } 318 return __ret; 319 } 320 321 template<typename _CharT, typename _Traits> 322 typename basic_filebuf<_CharT, _Traits>::int_type 323 basic_filebuf<_CharT, _Traits>:: 324 underflow() 325 { 326 int_type __ret = traits_type::eof(); 327 const bool __testin = _M_mode & ios_base::in; 328 if (__testin) 329 { 330 if (_M_writing) 331 { 332 if (overflow() == traits_type::eof()) 333 return __ret; 334 _M_set_buffer(-1); 335 _M_writing = false; 336 } 337 // Check for pback madness, and if so switch back to the 338 // normal buffers and jet outta here before expensive 339 // fileops happen... 340 _M_destroy_pback(); 341 342 if (this->gptr() < this->egptr()) 343 return traits_type::to_int_type(*this->gptr()); 344 345 // Get and convert input sequence. 346 const size_t __buflen = _M_buf_size > 1 ? _M_buf_size - 1 : 1; 347 348 // Will be set to true if ::read() returns 0 indicating EOF. 349 bool __got_eof = false; 350 // Number of internal characters produced. 351 streamsize __ilen = 0; 352 codecvt_base::result __r = codecvt_base::ok; 353 if (__check_facet(_M_codecvt).always_noconv()) 354 { 355 __ilen = _M_file.xsgetn(reinterpret_cast<char*>(this->eback()), 356 __buflen); 357 if (__ilen == 0) 358 __got_eof = true; 359 } 360 else 361 { 362 // Worst-case number of external bytes. 363 // XXX Not done encoding() == -1. 364 const int __enc = _M_codecvt->encoding(); 365 streamsize __blen; // Minimum buffer size. 366 streamsize __rlen; // Number of chars to read. 367 if (__enc > 0) 368 __blen = __rlen = __buflen * __enc; 369 else 370 { 371 __blen = __buflen + _M_codecvt->max_length() - 1; 372 __rlen = __buflen; 373 } 374 const streamsize __remainder = _M_ext_end - _M_ext_next; 375 __rlen = __rlen > __remainder ? __rlen - __remainder : 0; 376 377 // An imbue in 'read' mode implies first converting the external 378 // chars already present. 379 if (_M_reading && this->egptr() == this->eback() && __remainder) 380 __rlen = 0; 381 382 // Allocate buffer if necessary and move unconverted 383 // bytes to front. 384 if (_M_ext_buf_size < __blen) 385 { 386 char* __buf = new char[__blen]; 387 if (__remainder) 388 __builtin_memcpy(__buf, _M_ext_next, __remainder); 389 390 delete [] _M_ext_buf; 391 _M_ext_buf = __buf; 392 _M_ext_buf_size = __blen; 393 } 394 else if (__remainder) 395 __builtin_memmove(_M_ext_buf, _M_ext_next, __remainder); 396 397 _M_ext_next = _M_ext_buf; 398 _M_ext_end = _M_ext_buf + __remainder; 399 _M_state_last = _M_state_cur; 400 401 do 402 { 403 if (__rlen > 0) 404 { 405 // Sanity check! 406 // This may fail if the return value of 407 // codecvt::max_length() is bogus. 408 if (_M_ext_end - _M_ext_buf + __rlen > _M_ext_buf_size) 409 { 410 __throw_ios_failure(__N("basic_filebuf::underflow " 411 "codecvt::max_length() " 412 "is not valid")); 413 } 414 streamsize __elen = _M_file.xsgetn(_M_ext_end, __rlen); 415 if (__elen == 0) 416 __got_eof = true; 417 else if (__elen == -1) 418 break; 419 _M_ext_end += __elen; 420 } 421 422 char_type* __iend = this->eback(); 423 if (_M_ext_next < _M_ext_end) 424 __r = _M_codecvt->in(_M_state_cur, _M_ext_next, 425 _M_ext_end, _M_ext_next, 426 this->eback(), 427 this->eback() + __buflen, __iend); 428 if (__r == codecvt_base::noconv) 429 { 430 size_t __avail = _M_ext_end - _M_ext_buf; 431 __ilen = std::min(__avail, __buflen); 432 traits_type::copy(this->eback(), 433 reinterpret_cast<char_type*> 434 (_M_ext_buf), __ilen); 435 _M_ext_next = _M_ext_buf + __ilen; 436 } 437 else 438 __ilen = __iend - this->eback(); 439 440 // _M_codecvt->in may return error while __ilen > 0: this is 441 // ok, and actually occurs in case of mixed encodings (e.g., 442 // XML files). 443 if (__r == codecvt_base::error) 444 break; 445 446 __rlen = 1; 447 } 448 while (__ilen == 0 && !__got_eof); 449 } 450 451 if (__ilen > 0) 452 { 453 _M_set_buffer(__ilen); 454 _M_reading = true; 455 __ret = traits_type::to_int_type(*this->gptr()); 456 } 457 else if (__got_eof) 458 { 459 // If the actual end of file is reached, set 'uncommitted' 460 // mode, thus allowing an immediate write without an 461 // intervening seek. 462 _M_set_buffer(-1); 463 _M_reading = false; 464 // However, reaching it while looping on partial means that 465 // the file has got an incomplete character. 466 if (__r == codecvt_base::partial) 467 __throw_ios_failure(__N("basic_filebuf::underflow " 468 "incomplete character in file")); 469 } 470 else if (__r == codecvt_base::error) 471 __throw_ios_failure(__N("basic_filebuf::underflow " 472 "invalid byte sequence in file")); 473 else 474 __throw_ios_failure(__N("basic_filebuf::underflow " 475 "error reading the file"), errno); 476 } 477 return __ret; 478 } 479 480 template<typename _CharT, typename _Traits> 481 typename basic_filebuf<_CharT, _Traits>::int_type 482 basic_filebuf<_CharT, _Traits>:: 483 pbackfail(int_type __i) 484 { 485 int_type __ret = traits_type::eof(); 486 const bool __testin = _M_mode & ios_base::in; 487 if (__testin) 488 { 489 if (_M_writing) 490 { 491 if (overflow() == traits_type::eof()) 492 return __ret; 493 _M_set_buffer(-1); 494 _M_writing = false; 495 } 496 // Remember whether the pback buffer is active, otherwise below 497 // we may try to store in it a second char (libstdc++/9761). 498 const bool __testpb = _M_pback_init; 499 const bool __testeof = traits_type::eq_int_type(__i, __ret); 500 int_type __tmp; 501 if (this->eback() < this->gptr()) 502 { 503 this->gbump(-1); 504 __tmp = traits_type::to_int_type(*this->gptr()); 505 } 506 else if (this->seekoff(-1, ios_base::cur) != pos_type(off_type(-1))) 507 { 508 __tmp = this->underflow(); 509 if (traits_type::eq_int_type(__tmp, __ret)) 510 return __ret; 511 } 512 else 513 { 514 // At the beginning of the buffer, need to make a 515 // putback position available. But the seek may fail 516 // (f.i., at the beginning of a file, see 517 // libstdc++/9439) and in that case we return 518 // traits_type::eof(). 519 return __ret; 520 } 521 522 // Try to put back __i into input sequence in one of three ways. 523 // Order these tests done in is unspecified by the standard. 524 if (!__testeof && traits_type::eq_int_type(__i, __tmp)) 525 __ret = __i; 526 else if (__testeof) 527 __ret = traits_type::not_eof(__i); 528 else if (!__testpb) 529 { 530 _M_create_pback(); 531 _M_reading = true; 532 *this->gptr() = traits_type::to_char_type(__i); 533 __ret = __i; 534 } 535 } 536 return __ret; 537 } 538 539 template<typename _CharT, typename _Traits> 540 typename basic_filebuf<_CharT, _Traits>::int_type 541 basic_filebuf<_CharT, _Traits>:: 542 overflow(int_type __c) 543 { 544 int_type __ret = traits_type::eof(); 545 const bool __testeof = traits_type::eq_int_type(__c, __ret); 546 const bool __testout = (_M_mode & ios_base::out 547 || _M_mode & ios_base::app); 548 if (__testout) 549 { 550 if (_M_reading) 551 { 552 _M_destroy_pback(); 553 const int __gptr_off = _M_get_ext_pos(_M_state_last); 554 if (_M_seek(__gptr_off, ios_base::cur, _M_state_last) 555 == pos_type(off_type(-1))) 556 return __ret; 557 } 558 if (this->pbase() < this->pptr()) 559 { 560 // If appropriate, append the overflow char. 561 if (!__testeof) 562 { 563 *this->pptr() = traits_type::to_char_type(__c); 564 this->pbump(1); 565 } 566 567 // Convert pending sequence to external representation, 568 // and output. 569 if (_M_convert_to_external(this->pbase(), 570 this->pptr() - this->pbase())) 571 { 572 _M_set_buffer(0); 573 __ret = traits_type::not_eof(__c); 574 } 575 } 576 else if (_M_buf_size > 1) 577 { 578 // Overflow in 'uncommitted' mode: set _M_writing, set 579 // the buffer to the initial 'write' mode, and put __c 580 // into the buffer. 581 _M_set_buffer(0); 582 _M_writing = true; 583 if (!__testeof) 584 { 585 *this->pptr() = traits_type::to_char_type(__c); 586 this->pbump(1); 587 } 588 __ret = traits_type::not_eof(__c); 589 } 590 else 591 { 592 // Unbuffered. 593 char_type __conv = traits_type::to_char_type(__c); 594 if (__testeof || _M_convert_to_external(&__conv, 1)) 595 { 596 _M_writing = true; 597 __ret = traits_type::not_eof(__c); 598 } 599 } 600 } 601 return __ret; 602 } 603 604 template<typename _CharT, typename _Traits> 605 bool 606 basic_filebuf<_CharT, _Traits>:: 607 _M_convert_to_external(_CharT* __ibuf, streamsize __ilen) 608 { 609 // Sizes of external and pending output. 610 streamsize __elen; 611 streamsize __plen; 612 if (__check_facet(_M_codecvt).always_noconv()) 613 { 614 __elen = _M_file.xsputn(reinterpret_cast<char*>(__ibuf), __ilen); 615 __plen = __ilen; 616 } 617 else 618 { 619 // Worst-case number of external bytes needed. 620 // XXX Not done encoding() == -1. 621 streamsize __blen = __ilen * _M_codecvt->max_length(); 622 char* __buf = static_cast<char*>(__builtin_alloca(__blen)); 623 624 char* __bend; 625 const char_type* __iend; 626 codecvt_base::result __r; 627 __r = _M_codecvt->out(_M_state_cur, __ibuf, __ibuf + __ilen, 628 __iend, __buf, __buf + __blen, __bend); 629 630 if (__r == codecvt_base::ok || __r == codecvt_base::partial) 631 __blen = __bend - __buf; 632 else if (__r == codecvt_base::noconv) 633 { 634 // Same as the always_noconv case above. 635 __buf = reinterpret_cast<char*>(__ibuf); 636 __blen = __ilen; 637 } 638 else 639 __throw_ios_failure(__N("basic_filebuf::_M_convert_to_external " 640 "conversion error")); 641 642 __elen = _M_file.xsputn(__buf, __blen); 643 __plen = __blen; 644 645 // Try once more for partial conversions. 646 if (__r == codecvt_base::partial && __elen == __plen) 647 { 648 const char_type* __iresume = __iend; 649 streamsize __rlen = this->pptr() - __iend; 650 __r = _M_codecvt->out(_M_state_cur, __iresume, 651 __iresume + __rlen, __iend, __buf, 652 __buf + __blen, __bend); 653 if (__r != codecvt_base::error) 654 { 655 __rlen = __bend - __buf; 656 __elen = _M_file.xsputn(__buf, __rlen); 657 __plen = __rlen; 658 } 659 else 660 __throw_ios_failure(__N("basic_filebuf::_M_convert_to_external " 661 "conversion error")); 662 } 663 } 664 return __elen == __plen; 665 } 666 667 template<typename _CharT, typename _Traits> 668 streamsize 669 basic_filebuf<_CharT, _Traits>:: 670 xsgetn(_CharT* __s, streamsize __n) 671 { 672 // Clear out pback buffer before going on to the real deal... 673 streamsize __ret = 0; 674 if (_M_pback_init) 675 { 676 if (__n > 0 && this->gptr() == this->eback()) 677 { 678 *__s++ = *this->gptr(); // emulate non-underflowing sbumpc 679 this->gbump(1); 680 __ret = 1; 681 --__n; 682 } 683 _M_destroy_pback(); 684 } 685 else if (_M_writing) 686 { 687 if (overflow() == traits_type::eof()) 688 return __ret; 689 _M_set_buffer(-1); 690 _M_writing = false; 691 } 692 693 // Optimization in the always_noconv() case, to be generalized in the 694 // future: when __n > __buflen we read directly instead of using the 695 // buffer repeatedly. 696 const bool __testin = _M_mode & ios_base::in; 697 const streamsize __buflen = _M_buf_size > 1 ? _M_buf_size - 1 : 1; 698 699 if (__n > __buflen && __check_facet(_M_codecvt).always_noconv() 700 && __testin) 701 { 702 // First, copy the chars already present in the buffer. 703 const streamsize __avail = this->egptr() - this->gptr(); 704 if (__avail != 0) 705 { 706 traits_type::copy(__s, this->gptr(), __avail); 707 __s += __avail; 708 this->setg(this->eback(), this->gptr() + __avail, this->egptr()); 709 __ret += __avail; 710 __n -= __avail; 711 } 712 713 // Need to loop in case of short reads (relatively common 714 // with pipes). 715 streamsize __len; 716 for (;;) 717 { 718 __len = _M_file.xsgetn(reinterpret_cast<char*>(__s), __n); 719 if (__len == -1) 720 __throw_ios_failure(__N("basic_filebuf::xsgetn " 721 "error reading the file"), errno); 722 if (__len == 0) 723 break; 724 725 __n -= __len; 726 __ret += __len; 727 if (__n == 0) 728 break; 729 730 __s += __len; 731 } 732 733 if (__n == 0) 734 { 735 // Set _M_reading. Buffer is already in initial 'read' mode. 736 _M_reading = true; 737 } 738 else if (__len == 0) 739 { 740 // If end of file is reached, set 'uncommitted' 741 // mode, thus allowing an immediate write without 742 // an intervening seek. 743 _M_set_buffer(-1); 744 _M_reading = false; 745 } 746 } 747 else 748 __ret += __streambuf_type::xsgetn(__s, __n); 749 750 return __ret; 751 } 752 753 template<typename _CharT, typename _Traits> 754 streamsize 755 basic_filebuf<_CharT, _Traits>:: 756 xsputn(const _CharT* __s, streamsize __n) 757 { 758 streamsize __ret = 0; 759 // Optimization in the always_noconv() case, to be generalized in the 760 // future: when __n is sufficiently large we write directly instead of 761 // using the buffer. 762 const bool __testout = (_M_mode & ios_base::out 763 || _M_mode & ios_base::app); 764 if (__check_facet(_M_codecvt).always_noconv() 765 && __testout && !_M_reading) 766 { 767 // Measurement would reveal the best choice. 768 const streamsize __chunk = 1ul << 10; 769 streamsize __bufavail = this->epptr() - this->pptr(); 770 771 // Don't mistake 'uncommitted' mode buffered with unbuffered. 772 if (!_M_writing && _M_buf_size > 1) 773 __bufavail = _M_buf_size - 1; 774 775 const streamsize __limit = std::min(__chunk, __bufavail); 776 if (__n >= __limit) 777 { 778 const streamsize __buffill = this->pptr() - this->pbase(); 779 const char* __buf = reinterpret_cast<const char*>(this->pbase()); 780 __ret = _M_file.xsputn_2(__buf, __buffill, 781 reinterpret_cast<const char*>(__s), 782 __n); 783 if (__ret == __buffill + __n) 784 { 785 _M_set_buffer(0); 786 _M_writing = true; 787 } 788 if (__ret > __buffill) 789 __ret -= __buffill; 790 else 791 __ret = 0; 792 } 793 else 794 __ret = __streambuf_type::xsputn(__s, __n); 795 } 796 else 797 __ret = __streambuf_type::xsputn(__s, __n); 798 return __ret; 799 } 800 801 template<typename _CharT, typename _Traits> 802 typename basic_filebuf<_CharT, _Traits>::__streambuf_type* 803 basic_filebuf<_CharT, _Traits>:: 804 setbuf(char_type* __s, streamsize __n) 805 { 806 if (!this->is_open()) 807 { 808 if (__s == 0 && __n == 0) 809 _M_buf_size = 1; 810 else if (__s && __n > 0) 811 { 812 // This is implementation-defined behavior, and assumes that 813 // an external char_type array of length __n exists and has 814 // been pre-allocated. If this is not the case, things will 815 // quickly blow up. When __n > 1, __n - 1 positions will be 816 // used for the get area, __n - 1 for the put area and 1 817 // position to host the overflow char of a full put area. 818 // When __n == 1, 1 position will be used for the get area 819 // and 0 for the put area, as in the unbuffered case above. 820 _M_buf = __s; 821 _M_buf_size = __n; 822 } 823 } 824 return this; 825 } 826 827 828 // According to 27.8.1.4 p11 - 13, seekoff should ignore the last 829 // argument (of type openmode). 830 template<typename _CharT, typename _Traits> 831 typename basic_filebuf<_CharT, _Traits>::pos_type 832 basic_filebuf<_CharT, _Traits>:: 833 seekoff(off_type __off, ios_base::seekdir __way, ios_base::openmode) 834 { 835 int __width = 0; 836 if (_M_codecvt) 837 __width = _M_codecvt->encoding(); 838 if (__width < 0) 839 __width = 0; 840 841 pos_type __ret = pos_type(off_type(-1)); 842 const bool __testfail = __off != 0 && __width <= 0; 843 if (this->is_open() && !__testfail) 844 { 845 // tellg and tellp queries do not affect any state, unless 846 // ! always_noconv and the put sequence is not empty. 847 // In that case, determining the position requires converting the 848 // put sequence. That doesn't use ext_buf, so requires a flush. 849 bool __no_movement = __way == ios_base::cur && __off == 0 850 && (!_M_writing || _M_codecvt->always_noconv()); 851 852 // Ditch any pback buffers to avoid confusion. 853 if (!__no_movement) 854 _M_destroy_pback(); 855 856 // Correct state at destination. Note that this is the correct 857 // state for the current position during output, because 858 // codecvt::unshift() returns the state to the initial state. 859 // This is also the correct state at the end of the file because 860 // an unshift sequence should have been written at the end. 861 __state_type __state = _M_state_beg; 862 off_type __computed_off = __off * __width; 863 if (_M_reading && __way == ios_base::cur) 864 { 865 __state = _M_state_last; 866 __computed_off += _M_get_ext_pos(__state); 867 } 868 if (!__no_movement) 869 __ret = _M_seek(__computed_off, __way, __state); 870 else 871 { 872 if (_M_writing) 873 __computed_off = this->pptr() - this->pbase(); 874 875 off_type __file_off = _M_file.seekoff(0, ios_base::cur); 876 if (__file_off != off_type(-1)) 877 { 878 __ret = __file_off + __computed_off; 879 __ret.state(__state); 880 } 881 } 882 } 883 return __ret; 884 } 885 886 // _GLIBCXX_RESOLVE_LIB_DEFECTS 887 // 171. Strange seekpos() semantics due to joint position 888 // According to the resolution of DR 171, seekpos should ignore the last 889 // argument (of type openmode). 890 template<typename _CharT, typename _Traits> 891 typename basic_filebuf<_CharT, _Traits>::pos_type 892 basic_filebuf<_CharT, _Traits>:: 893 seekpos(pos_type __pos, ios_base::openmode) 894 { 895 pos_type __ret = pos_type(off_type(-1)); 896 if (this->is_open()) 897 { 898 // Ditch any pback buffers to avoid confusion. 899 _M_destroy_pback(); 900 __ret = _M_seek(off_type(__pos), ios_base::beg, __pos.state()); 901 } 902 return __ret; 903 } 904 905 template<typename _CharT, typename _Traits> 906 typename basic_filebuf<_CharT, _Traits>::pos_type 907 basic_filebuf<_CharT, _Traits>:: 908 _M_seek(off_type __off, ios_base::seekdir __way, __state_type __state) 909 { 910 pos_type __ret = pos_type(off_type(-1)); 911 if (_M_terminate_output()) 912 { 913 off_type __file_off = _M_file.seekoff(__off, __way); 914 if (__file_off != off_type(-1)) 915 { 916 _M_reading = false; 917 _M_writing = false; 918 _M_ext_next = _M_ext_end = _M_ext_buf; 919 _M_set_buffer(-1); 920 _M_state_cur = __state; 921 __ret = __file_off; 922 __ret.state(_M_state_cur); 923 } 924 } 925 return __ret; 926 } 927 928 // Returns the distance from the end of the ext buffer to the point 929 // corresponding to gptr(). This is a negative value. Updates __state 930 // from eback() correspondence to gptr(). 931 template<typename _CharT, typename _Traits> 932 int basic_filebuf<_CharT, _Traits>:: 933 _M_get_ext_pos(__state_type& __state) 934 { 935 if (_M_codecvt->always_noconv()) 936 return this->gptr() - this->egptr(); 937 else 938 { 939 // Calculate offset from _M_ext_buf that corresponds to 940 // gptr(). Precondition: __state == _M_state_last, which 941 // corresponds to eback(). 942 const int __gptr_off = 943 _M_codecvt->length(__state, _M_ext_buf, _M_ext_next, 944 this->gptr() - this->eback()); 945 return _M_ext_buf + __gptr_off - _M_ext_end; 946 } 947 } 948 949 template<typename _CharT, typename _Traits> 950 bool 951 basic_filebuf<_CharT, _Traits>:: 952 _M_terminate_output() 953 { 954 // Part one: update the output sequence. 955 bool __testvalid = true; 956 if (this->pbase() < this->pptr()) 957 { 958 const int_type __tmp = this->overflow(); 959 if (traits_type::eq_int_type(__tmp, traits_type::eof())) 960 __testvalid = false; 961 } 962 963 // Part two: output unshift sequence. 964 if (_M_writing && !__check_facet(_M_codecvt).always_noconv() 965 && __testvalid) 966 { 967 // Note: this value is arbitrary, since there is no way to 968 // get the length of the unshift sequence from codecvt, 969 // without calling unshift. 970 const size_t __blen = 128; 971 char __buf[__blen]; 972 codecvt_base::result __r; 973 streamsize __ilen = 0; 974 975 do 976 { 977 char* __next; 978 __r = _M_codecvt->unshift(_M_state_cur, __buf, 979 __buf + __blen, __next); 980 if (__r == codecvt_base::error) 981 __testvalid = false; 982 else if (__r == codecvt_base::ok || 983 __r == codecvt_base::partial) 984 { 985 __ilen = __next - __buf; 986 if (__ilen > 0) 987 { 988 const streamsize __elen = _M_file.xsputn(__buf, __ilen); 989 if (__elen != __ilen) 990 __testvalid = false; 991 } 992 } 993 } 994 while (__r == codecvt_base::partial && __ilen > 0 && __testvalid); 995 996 if (__testvalid) 997 { 998 // This second call to overflow() is required by the standard, 999 // but it's not clear why it's needed, since the output buffer 1000 // should be empty by this point (it should have been emptied 1001 // in the first call to overflow()). 1002 const int_type __tmp = this->overflow(); 1003 if (traits_type::eq_int_type(__tmp, traits_type::eof())) 1004 __testvalid = false; 1005 } 1006 } 1007 return __testvalid; 1008 } 1009 1010 template<typename _CharT, typename _Traits> 1011 int 1012 basic_filebuf<_CharT, _Traits>:: 1013 sync() 1014 { 1015 // Make sure that the internal buffer resyncs its idea of 1016 // the file position with the external file. 1017 int __ret = 0; 1018 if (this->pbase() < this->pptr()) 1019 { 1020 const int_type __tmp = this->overflow(); 1021 if (traits_type::eq_int_type(__tmp, traits_type::eof())) 1022 __ret = -1; 1023 } 1024 return __ret; 1025 } 1026 1027 template<typename _CharT, typename _Traits> 1028 void 1029 basic_filebuf<_CharT, _Traits>:: 1030 imbue(const locale& __loc) 1031 { 1032 bool __testvalid = true; 1033 1034 const __codecvt_type* _M_codecvt_tmp = 0; 1035 if (__builtin_expect(has_facet<__codecvt_type>(__loc), true)) 1036 _M_codecvt_tmp = &use_facet<__codecvt_type>(__loc); 1037 1038 if (this->is_open()) 1039 { 1040 // encoding() == -1 is ok only at the beginning. 1041 if ((_M_reading || _M_writing) 1042 && __check_facet(_M_codecvt).encoding() == -1) 1043 __testvalid = false; 1044 else 1045 { 1046 if (_M_reading) 1047 { 1048 if (__check_facet(_M_codecvt).always_noconv()) 1049 { 1050 if (_M_codecvt_tmp 1051 && !__check_facet(_M_codecvt_tmp).always_noconv()) 1052 __testvalid = this->seekoff(0, ios_base::cur, _M_mode) 1053 != pos_type(off_type(-1)); 1054 } 1055 else 1056 { 1057 // External position corresponding to gptr(). 1058 _M_ext_next = _M_ext_buf 1059 + _M_codecvt->length(_M_state_last, _M_ext_buf, 1060 _M_ext_next, 1061 this->gptr() - this->eback()); 1062 const streamsize __remainder = _M_ext_end - _M_ext_next; 1063 if (__remainder) 1064 __builtin_memmove(_M_ext_buf, _M_ext_next, __remainder); 1065 1066 _M_ext_next = _M_ext_buf; 1067 _M_ext_end = _M_ext_buf + __remainder; 1068 _M_set_buffer(-1); 1069 _M_state_last = _M_state_cur = _M_state_beg; 1070 } 1071 } 1072 else if (_M_writing && (__testvalid = _M_terminate_output())) 1073 _M_set_buffer(-1); 1074 } 1075 } 1076 1077 if (__testvalid) 1078 _M_codecvt = _M_codecvt_tmp; 1079 else 1080 _M_codecvt = 0; 1081 } 1082 1083 // Inhibit implicit instantiations for required instantiations, 1084 // which are defined via explicit instantiations elsewhere. 1085 #if _GLIBCXX_EXTERN_TEMPLATE 1086 extern template class basic_filebuf<char>; 1087 extern template class basic_ifstream<char>; 1088 extern template class basic_ofstream<char>; 1089 extern template class basic_fstream<char>; 1090 1091 #ifdef _GLIBCXX_USE_WCHAR_T 1092 extern template class basic_filebuf<wchar_t>; 1093 extern template class basic_ifstream<wchar_t>; 1094 extern template class basic_ofstream<wchar_t>; 1095 extern template class basic_fstream<wchar_t>; 1096 #endif 1097 #endif 1098 1099 _GLIBCXX_END_NAMESPACE_VERSION 1100 } // namespace std 1101 1102 #endif
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