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The C and C++ Include Header Files
cat -n /usr/include/c++/15/bits/fstream.tcc
1 // File based streams -*- C++ -*- 2 3 // Copyright (C) 1997-2025 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 #ifdef _GLIBCXX_SYSHDR 38 #pragma GCC system_header 39 #endif 40 41 #pragma GCC diagnostic push 42 #pragma GCC diagnostic ignored "-Wc++11-extensions" // extern template 43 44 #include <bits/cxxabi_forced.h> 45 #include <bits/move.h> // for swap 46 #include <cerrno> 47 48 namespace std _GLIBCXX_VISIBILITY(default) 49 { 50 _GLIBCXX_BEGIN_NAMESPACE_VERSION 51 52 template<typename _CharT, typename _Traits> 53 void 54 basic_filebuf<_CharT, _Traits>:: 55 _M_allocate_internal_buffer() 56 { 57 // Allocate internal buffer only if one doesn't already exist 58 // (either allocated or provided by the user via setbuf). 59 if (!_M_buf_allocated && !_M_buf) 60 { 61 _M_buf = new char_type[_M_buf_size]; 62 _M_buf_allocated = true; 63 } 64 } 65 66 template<typename _CharT, typename _Traits> 67 void 68 basic_filebuf<_CharT, _Traits>:: 69 _M_destroy_internal_buffer() throw() 70 { 71 if (_M_buf_allocated) 72 { 73 delete [] _M_buf; 74 _M_buf = 0; 75 _M_buf_allocated = false; 76 } 77 delete [] _M_ext_buf; 78 _M_ext_buf = 0; 79 _M_ext_buf_size = 0; 80 _M_ext_next = 0; 81 _M_ext_end = 0; 82 } 83 84 template<typename _CharT, typename _Traits> 85 basic_filebuf<_CharT, _Traits>:: 86 basic_filebuf() : __streambuf_type(), _M_lock(), _M_file(&_M_lock), 87 _M_mode(ios_base::openmode(0)), _M_state_beg(), _M_state_cur(), 88 _M_state_last(), _M_buf(0), _M_buf_size(_GLIBCXX_BUFSIZ), 89 _M_buf_allocated(false), _M_reading(false), _M_writing(false), _M_pback(), 90 _M_pback_cur_save(0), _M_pback_end_save(0), _M_pback_init(false), 91 _M_codecvt(0), _M_ext_buf(0), _M_ext_buf_size(0), _M_ext_next(0), 92 _M_ext_end(0) 93 { 94 _M_codecvt = std::__try_use_facet<__codecvt_type>(this->_M_buf_locale); 95 } 96 97 #if __cplusplus >= 201103L 98 template<typename _CharT, typename _Traits> 99 basic_filebuf<_CharT, _Traits>:: 100 basic_filebuf(basic_filebuf&& __rhs) 101 : __streambuf_type(__rhs), 102 _M_lock(), _M_file(std::move(__rhs._M_file), &_M_lock), 103 _M_mode(std::__exchange(__rhs._M_mode, ios_base::openmode(0))), 104 _M_state_beg(std::move(__rhs._M_state_beg)), 105 _M_state_cur(std::move(__rhs._M_state_cur)), 106 _M_state_last(std::move(__rhs._M_state_last)), 107 _M_buf(std::__exchange(__rhs._M_buf, nullptr)), 108 _M_buf_size(std::__exchange(__rhs._M_buf_size, 1)), 109 _M_buf_allocated(std::__exchange(__rhs._M_buf_allocated, false)), 110 _M_reading(std::__exchange(__rhs._M_reading, false)), 111 _M_writing(std::__exchange(__rhs._M_writing, false)), 112 _M_pback(__rhs._M_pback), 113 _M_pback_cur_save(std::__exchange(__rhs._M_pback_cur_save, nullptr)), 114 _M_pback_end_save(std::__exchange(__rhs._M_pback_end_save, nullptr)), 115 _M_pback_init(std::__exchange(__rhs._M_pback_init, false)), 116 _M_codecvt(__rhs._M_codecvt), 117 _M_ext_buf(std::__exchange(__rhs._M_ext_buf, nullptr)), 118 _M_ext_buf_size(std::__exchange(__rhs._M_ext_buf_size, 0)), 119 _M_ext_next(std::__exchange(__rhs._M_ext_next, nullptr)), 120 _M_ext_end(std::__exchange(__rhs._M_ext_end, nullptr)) 121 { 122 __rhs._M_set_buffer(-1); 123 __rhs._M_state_last = __rhs._M_state_cur = __rhs._M_state_beg; 124 } 125 126 template<typename _CharT, typename _Traits> 127 basic_filebuf<_CharT, _Traits>& 128 basic_filebuf<_CharT, _Traits>:: 129 operator=(basic_filebuf&& __rhs) 130 { 131 this->close(); 132 __streambuf_type::operator=(__rhs); 133 _M_file.swap(__rhs._M_file); 134 _M_mode = std::__exchange(__rhs._M_mode, ios_base::openmode(0)); 135 _M_state_beg = std::move(__rhs._M_state_beg); 136 _M_state_cur = std::move(__rhs._M_state_cur); 137 _M_state_last = std::move(__rhs._M_state_last); 138 _M_buf = std::__exchange(__rhs._M_buf, nullptr); 139 _M_buf_size = std::__exchange(__rhs._M_buf_size, 1); 140 _M_buf_allocated = std::__exchange(__rhs._M_buf_allocated, false); 141 _M_ext_buf = std::__exchange(__rhs._M_ext_buf, nullptr); 142 _M_ext_buf_size = std::__exchange(__rhs._M_ext_buf_size, 0); 143 _M_ext_next = std::__exchange(__rhs._M_ext_next, nullptr); 144 _M_ext_end = std::__exchange(__rhs._M_ext_end, nullptr); 145 _M_reading = std::__exchange(__rhs._M_reading, false); 146 _M_writing = std::__exchange(__rhs._M_writing, false); 147 _M_pback_cur_save = std::__exchange(__rhs._M_pback_cur_save, nullptr); 148 _M_pback_end_save = std::__exchange(__rhs._M_pback_end_save, nullptr); 149 _M_pback_init = std::__exchange(__rhs._M_pback_init, false); 150 __rhs._M_set_buffer(-1); 151 __rhs._M_state_last = __rhs._M_state_cur = __rhs._M_state_beg; 152 return *this; 153 } 154 155 template<typename _CharT, typename _Traits> 156 void 157 basic_filebuf<_CharT, _Traits>:: 158 swap(basic_filebuf& __rhs) 159 { 160 __streambuf_type::swap(__rhs); 161 _M_file.swap(__rhs._M_file); 162 std::swap(_M_mode, __rhs._M_mode); 163 std::swap(_M_state_beg, __rhs._M_state_beg); 164 std::swap(_M_state_cur, __rhs._M_state_cur); 165 std::swap(_M_state_last, __rhs._M_state_last); 166 std::swap(_M_buf, __rhs._M_buf); 167 std::swap(_M_buf_size, __rhs._M_buf_size); 168 std::swap(_M_buf_allocated, __rhs._M_buf_allocated); 169 std::swap(_M_ext_buf, __rhs._M_ext_buf); 170 std::swap(_M_ext_buf_size, __rhs._M_ext_buf_size); 171 std::swap(_M_ext_next, __rhs._M_ext_next); 172 std::swap(_M_ext_end, __rhs._M_ext_end); 173 std::swap(_M_reading, __rhs._M_reading); 174 std::swap(_M_writing, __rhs._M_writing); 175 std::swap(_M_pback_cur_save, __rhs._M_pback_cur_save); 176 std::swap(_M_pback_end_save, __rhs._M_pback_end_save); 177 std::swap(_M_pback_init, __rhs._M_pback_init); 178 } 179 #endif 180 181 template<typename _CharT, typename _Traits> 182 typename basic_filebuf<_CharT, _Traits>::__filebuf_type* 183 basic_filebuf<_CharT, _Traits>:: 184 open(const char* __s, ios_base::openmode __mode) 185 { 186 __filebuf_type *__ret = 0; 187 if (!this->is_open()) 188 { 189 _M_file.open(__s, __mode); 190 if (this->is_open()) 191 { 192 _M_allocate_internal_buffer(); 193 _M_mode = __mode; 194 195 // Setup initial buffer to 'uncommitted' mode. 196 _M_reading = false; 197 _M_writing = false; 198 _M_set_buffer(-1); 199 200 // Reset to initial state. 201 _M_state_last = _M_state_cur = _M_state_beg; 202 203 // 27.8.1.3,4 204 if ((__mode & ios_base::ate) 205 && this->seekoff(0, ios_base::end, __mode) 206 == pos_type(off_type(-1))) 207 this->close(); 208 else 209 __ret = this; 210 } 211 } 212 return __ret; 213 } 214 215 #if _GLIBCXX_HAVE__WFOPEN && _GLIBCXX_USE_WCHAR_T 216 template<typename _CharT, typename _Traits> 217 basic_filebuf<_CharT, _Traits>* 218 basic_filebuf<_CharT, _Traits>:: 219 open(const wchar_t* __s, ios_base::openmode __mode) 220 { 221 __filebuf_type *__ret = 0; 222 if (!this->is_open()) 223 { 224 _M_file.open(__s, __mode); 225 if (this->is_open()) 226 { 227 _M_allocate_internal_buffer(); 228 _M_mode = __mode; 229 230 // Setup initial buffer to 'uncommitted' mode. 231 _M_reading = false; 232 _M_writing = false; 233 _M_set_buffer(-1); 234 235 // Reset to initial state. 236 _M_state_last = _M_state_cur = _M_state_beg; 237 238 // 27.8.1.3,4 239 if ((__mode & ios_base::ate) 240 && this->seekoff(0, ios_base::end, __mode) 241 == pos_type(off_type(-1))) 242 this->close(); 243 else 244 __ret = this; 245 } 246 } 247 return __ret; 248 } 249 #endif // HAVE__WFOPEN && USE_WCHAR_T 250 251 template<typename _CharT, typename _Traits> 252 typename basic_filebuf<_CharT, _Traits>::__filebuf_type* 253 basic_filebuf<_CharT, _Traits>:: 254 close() 255 { 256 if (!this->is_open()) 257 return 0; 258 259 bool __testfail = false; 260 { 261 // NB: Do this here so that re-opened filebufs will be cool... 262 struct __close_sentry 263 { 264 basic_filebuf *__fb; 265 __close_sentry (basic_filebuf *__fbi): __fb(__fbi) { } 266 ~__close_sentry () 267 { 268 __fb->_M_mode = ios_base::openmode(0); 269 __fb->_M_pback_init = false; 270 __fb->_M_destroy_internal_buffer(); 271 __fb->_M_reading = false; 272 __fb->_M_writing = false; 273 __fb->_M_set_buffer(-1); 274 __fb->_M_state_last = __fb->_M_state_cur = __fb->_M_state_beg; 275 } 276 } __cs (this); 277 278 __try 279 { 280 if (!_M_terminate_output()) 281 __testfail = true; 282 } 283 __catch(...) 284 { 285 _M_file.close(); 286 __throw_exception_again; 287 } 288 } 289 290 if (!_M_file.close()) 291 __testfail = true; 292 293 if (__testfail) 294 return 0; 295 else 296 return this; 297 } 298 299 template<typename _CharT, typename _Traits> 300 streamsize 301 basic_filebuf<_CharT, _Traits>:: 302 showmanyc() 303 { 304 streamsize __ret = -1; 305 const bool __testin = _M_mode & ios_base::in; 306 if (__testin && this->is_open()) 307 { 308 // For a stateful encoding (-1) the pending sequence might be just 309 // shift and unshift prefixes with no actual character. 310 __ret = this->egptr() - this->gptr(); 311 312 #if _GLIBCXX_HAVE_DOS_BASED_FILESYSTEM 313 // About this workaround, see libstdc++/20806. 314 const bool __testbinary = _M_mode & ios_base::binary; 315 if (__check_facet(_M_codecvt).encoding() >= 0 316 && __testbinary) 317 #else 318 if (__check_facet(_M_codecvt).encoding() >= 0) 319 #endif 320 __ret += _M_file.showmanyc() / _M_codecvt->max_length(); 321 } 322 return __ret; 323 } 324 325 template<typename _CharT, typename _Traits> 326 typename basic_filebuf<_CharT, _Traits>::int_type 327 basic_filebuf<_CharT, _Traits>:: 328 underflow() 329 { 330 int_type __ret = traits_type::eof(); 331 const bool __testin = _M_mode & ios_base::in; 332 if (__testin) 333 { 334 if (_M_writing) 335 { 336 if (overflow() == traits_type::eof()) 337 return __ret; 338 _M_set_buffer(-1); 339 _M_writing = false; 340 } 341 // Check for pback madness, and if so switch back to the 342 // normal buffers and jet outta here before expensive 343 // fileops happen... 344 _M_destroy_pback(); 345 346 if (this->gptr() < this->egptr()) 347 return traits_type::to_int_type(*this->gptr()); 348 349 // Get and convert input sequence. 350 const size_t __buflen = _M_buf_size > 1 ? _M_buf_size - 1 : 1; 351 352 // Will be set to true if ::read() returns 0 indicating EOF. 353 bool __got_eof = false; 354 // Number of internal characters produced. 355 streamsize __ilen = 0; 356 codecvt_base::result __r = codecvt_base::ok; 357 if (__check_facet(_M_codecvt).always_noconv()) 358 { 359 __ilen = _M_file.xsgetn(reinterpret_cast<char*>(this->eback()), 360 __buflen); 361 if (__ilen == 0) 362 __got_eof = true; 363 } 364 else 365 { 366 // Worst-case number of external bytes. 367 // XXX Not done encoding() == -1. 368 const int __enc = _M_codecvt->encoding(); 369 streamsize __blen; // Minimum buffer size. 370 streamsize __rlen; // Number of chars to read. 371 if (__enc > 0) 372 __blen = __rlen = __buflen * __enc; 373 else 374 { 375 __blen = __buflen + _M_codecvt->max_length() - 1; 376 __rlen = __buflen; 377 } 378 const streamsize __remainder = _M_ext_end - _M_ext_next; 379 __rlen = __rlen > __remainder ? __rlen - __remainder : 0; 380 381 // An imbue in 'read' mode implies first converting the external 382 // chars already present. 383 if (_M_reading && this->egptr() == this->eback() && __remainder) 384 __rlen = 0; 385 386 // Allocate buffer if necessary and move unconverted 387 // bytes to front. 388 if (_M_ext_buf_size < __blen) 389 { 390 char* __buf = new char[__blen]; 391 if (__remainder) 392 __builtin_memcpy(__buf, _M_ext_next, __remainder); 393 394 delete [] _M_ext_buf; 395 _M_ext_buf = __buf; 396 _M_ext_buf_size = __blen; 397 } 398 else if (__remainder) 399 __builtin_memmove(_M_ext_buf, _M_ext_next, __remainder); 400 401 _M_ext_next = _M_ext_buf; 402 _M_ext_end = _M_ext_buf + __remainder; 403 _M_state_last = _M_state_cur; 404 405 do 406 { 407 if (__rlen > 0) 408 { 409 // Sanity check! 410 // This may fail if the return value of 411 // codecvt::max_length() is bogus. 412 if (_M_ext_end - _M_ext_buf + __rlen > _M_ext_buf_size) 413 { 414 __throw_ios_failure(__N("basic_filebuf::underflow " 415 "codecvt::max_length() " 416 "is not valid")); 417 } 418 streamsize __elen = _M_file.xsgetn(_M_ext_end, __rlen); 419 if (__elen == 0) 420 __got_eof = true; 421 else if (__elen == -1) 422 break; 423 _M_ext_end += __elen; 424 } 425 426 char_type* __iend = this->eback(); 427 if (_M_ext_next < _M_ext_end) 428 __r = _M_codecvt->in(_M_state_cur, _M_ext_next, 429 _M_ext_end, _M_ext_next, 430 this->eback(), 431 this->eback() + __buflen, __iend); 432 if (__r == codecvt_base::noconv) 433 { 434 size_t __avail = _M_ext_end - _M_ext_buf; 435 __ilen = std::min(__avail, __buflen); 436 traits_type::copy(this->eback(), 437 reinterpret_cast<char_type*> 438 (_M_ext_buf), __ilen); 439 _M_ext_next = _M_ext_buf + __ilen; 440 } 441 else 442 __ilen = __iend - this->eback(); 443 444 // _M_codecvt->in may return error while __ilen > 0: this is 445 // ok, and actually occurs in case of mixed encodings (e.g., 446 // XML files). 447 if (__r == codecvt_base::error) 448 break; 449 450 __rlen = 1; 451 } 452 while (__ilen == 0 && !__got_eof); 453 } 454 455 if (__ilen > 0) 456 { 457 _M_set_buffer(__ilen); 458 _M_reading = true; 459 __ret = traits_type::to_int_type(*this->gptr()); 460 } 461 else if (__got_eof) 462 { 463 // If the actual end of file is reached, set 'uncommitted' 464 // mode, thus allowing an immediate write without an 465 // intervening seek. 466 _M_set_buffer(-1); 467 _M_reading = false; 468 // However, reaching it while looping on partial means that 469 // the file has got an incomplete character. 470 if (__r == codecvt_base::partial) 471 __throw_ios_failure(__N("basic_filebuf::underflow " 472 "incomplete character in file")); 473 } 474 else if (__r == codecvt_base::error) 475 __throw_ios_failure(__N("basic_filebuf::underflow " 476 "invalid byte sequence in file")); 477 else 478 __throw_ios_failure(__N("basic_filebuf::underflow " 479 "error reading the file"), errno); 480 } 481 return __ret; 482 } 483 484 template<typename _CharT, typename _Traits> 485 typename basic_filebuf<_CharT, _Traits>::int_type 486 basic_filebuf<_CharT, _Traits>:: 487 pbackfail(int_type __i) 488 { 489 int_type __ret = traits_type::eof(); 490 const bool __testin = _M_mode & ios_base::in; 491 if (__testin) 492 { 493 if (_M_writing) 494 { 495 if (overflow() == traits_type::eof()) 496 return __ret; 497 _M_set_buffer(-1); 498 _M_writing = false; 499 } 500 // Remember whether the pback buffer is active, otherwise below 501 // we may try to store in it a second char (libstdc++/9761). 502 const bool __testpb = _M_pback_init; 503 const bool __testeof = traits_type::eq_int_type(__i, __ret); 504 int_type __tmp; 505 if (this->eback() < this->gptr()) 506 { 507 this->gbump(-1); 508 __tmp = traits_type::to_int_type(*this->gptr()); 509 } 510 else if (this->seekoff(-1, ios_base::cur) != pos_type(off_type(-1))) 511 { 512 __tmp = this->underflow(); 513 if (traits_type::eq_int_type(__tmp, __ret)) 514 return __ret; 515 } 516 else 517 { 518 // At the beginning of the buffer, need to make a 519 // putback position available. But the seek may fail 520 // (f.i., at the beginning of a file, see 521 // libstdc++/9439) and in that case we return 522 // traits_type::eof(). 523 return __ret; 524 } 525 526 // Try to put back __i into input sequence in one of three ways. 527 // Order these tests done in is unspecified by the standard. 528 if (!__testeof && traits_type::eq_int_type(__i, __tmp)) 529 __ret = __i; 530 else if (__testeof) 531 __ret = traits_type::not_eof(__i); 532 else if (!__testpb) 533 { 534 _M_create_pback(); 535 _M_reading = true; 536 *this->gptr() = traits_type::to_char_type(__i); 537 __ret = __i; 538 } 539 } 540 return __ret; 541 } 542 543 template<typename _CharT, typename _Traits> 544 typename basic_filebuf<_CharT, _Traits>::int_type 545 basic_filebuf<_CharT, _Traits>:: 546 overflow(int_type __c) 547 { 548 int_type __ret = traits_type::eof(); 549 const bool __testeof = traits_type::eq_int_type(__c, __ret); 550 const bool __testout = (_M_mode & ios_base::out 551 || _M_mode & ios_base::app); 552 if (__testout) 553 { 554 if (_M_reading) 555 { 556 _M_destroy_pback(); 557 const int __gptr_off = _M_get_ext_pos(_M_state_last); 558 if (_M_seek(__gptr_off, ios_base::cur, _M_state_last) 559 == pos_type(off_type(-1))) 560 return __ret; 561 } 562 if (this->pbase() < this->pptr()) 563 { 564 // If appropriate, append the overflow char. 565 if (!__testeof) 566 { 567 *this->pptr() = traits_type::to_char_type(__c); 568 this->pbump(1); 569 } 570 571 // Convert pending sequence to external representation, 572 // and output. 573 if (_M_convert_to_external(this->pbase(), 574 this->pptr() - this->pbase())) 575 { 576 _M_set_buffer(0); 577 __ret = traits_type::not_eof(__c); 578 } 579 } 580 else if (_M_buf_size > 1) 581 { 582 // Overflow in 'uncommitted' mode: set _M_writing, set 583 // the buffer to the initial 'write' mode, and put __c 584 // into the buffer. 585 _M_set_buffer(0); 586 _M_writing = true; 587 if (!__testeof) 588 { 589 *this->pptr() = traits_type::to_char_type(__c); 590 this->pbump(1); 591 } 592 __ret = traits_type::not_eof(__c); 593 } 594 else 595 { 596 // Unbuffered. 597 char_type __conv = traits_type::to_char_type(__c); 598 if (__testeof || _M_convert_to_external(&__conv, 1)) 599 { 600 _M_writing = true; 601 __ret = traits_type::not_eof(__c); 602 } 603 } 604 } 605 return __ret; 606 } 607 608 template<typename _CharT, typename _Traits> 609 bool 610 basic_filebuf<_CharT, _Traits>:: 611 _M_convert_to_external(_CharT* __ibuf, streamsize __ilen) 612 { 613 // Sizes of external and pending output. 614 streamsize __elen; 615 streamsize __plen; 616 if (__check_facet(_M_codecvt).always_noconv()) 617 { 618 __elen = _M_file.xsputn(reinterpret_cast<char*>(__ibuf), __ilen); 619 __plen = __ilen; 620 } 621 else 622 { 623 // Worst-case number of external bytes needed. 624 // XXX Not done encoding() == -1. 625 streamsize __blen = __ilen * _M_codecvt->max_length(); 626 char* __buf = static_cast<char*>(__builtin_alloca(__blen)); 627 628 char* __bend; 629 const char_type* __iend; 630 codecvt_base::result __r; 631 __r = _M_codecvt->out(_M_state_cur, __ibuf, __ibuf + __ilen, 632 __iend, __buf, __buf + __blen, __bend); 633 634 if (__r == codecvt_base::ok || __r == codecvt_base::partial) 635 __blen = __bend - __buf; 636 else if (__r == codecvt_base::noconv) 637 { 638 // Same as the always_noconv case above. 639 __buf = reinterpret_cast<char*>(__ibuf); 640 __blen = __ilen; 641 } 642 else 643 __throw_ios_failure(__N("basic_filebuf::_M_convert_to_external " 644 "conversion error")); 645 646 __elen = _M_file.xsputn(__buf, __blen); 647 __plen = __blen; 648 649 // Try once more for partial conversions. 650 if (__r == codecvt_base::partial && __elen == __plen) 651 { 652 const char_type* __iresume = __iend; 653 streamsize __rlen = this->pptr() - __iend; 654 __r = _M_codecvt->out(_M_state_cur, __iresume, 655 __iresume + __rlen, __iend, __buf, 656 __buf + __blen, __bend); 657 if (__r != codecvt_base::error) 658 { 659 __rlen = __bend - __buf; 660 __elen = _M_file.xsputn(__buf, __rlen); 661 __plen = __rlen; 662 } 663 else 664 __throw_ios_failure(__N("basic_filebuf::_M_convert_to_external " 665 "conversion error")); 666 } 667 } 668 return __elen == __plen; 669 } 670 671 template<typename _CharT, typename _Traits> 672 streamsize 673 basic_filebuf<_CharT, _Traits>:: 674 xsgetn(_CharT* __s, streamsize __n) 675 { 676 // Clear out pback buffer before going on to the real deal... 677 streamsize __ret = 0; 678 if (_M_pback_init) 679 { 680 if (__n > 0 && this->gptr() == this->eback()) 681 { 682 *__s++ = *this->gptr(); // emulate non-underflowing sbumpc 683 this->gbump(1); 684 __ret = 1; 685 --__n; 686 } 687 _M_destroy_pback(); 688 } 689 else if (_M_writing) 690 { 691 if (overflow() == traits_type::eof()) 692 return __ret; 693 _M_set_buffer(-1); 694 _M_writing = false; 695 } 696 697 // Optimization in the always_noconv() case, to be generalized in the 698 // future: when __n > __buflen we read directly instead of using the 699 // buffer repeatedly. 700 const bool __testin = _M_mode & ios_base::in; 701 const streamsize __buflen = _M_buf_size > 1 ? _M_buf_size - 1 : 1; 702 703 if (__n > __buflen && __check_facet(_M_codecvt).always_noconv() 704 && __testin) 705 { 706 // First, copy the chars already present in the buffer. 707 const streamsize __avail = this->egptr() - this->gptr(); 708 if (__avail != 0) 709 { 710 traits_type::copy(__s, this->gptr(), __avail); 711 __s += __avail; 712 this->setg(this->eback(), this->gptr() + __avail, this->egptr()); 713 __ret += __avail; 714 __n -= __avail; 715 } 716 717 // Need to loop in case of short reads (relatively common 718 // with pipes). 719 streamsize __len; 720 for (;;) 721 { 722 __len = _M_file.xsgetn(reinterpret_cast<char*>(__s), __n); 723 if (__len == -1) 724 __throw_ios_failure(__N("basic_filebuf::xsgetn " 725 "error reading the file"), errno); 726 if (__len == 0) 727 break; 728 729 __n -= __len; 730 __ret += __len; 731 if (__n == 0) 732 break; 733 734 __s += __len; 735 } 736 737 if (__n == 0) 738 { 739 // Set _M_reading. Buffer is already in initial 'read' mode. 740 _M_reading = true; 741 } 742 else if (__len == 0) 743 { 744 // If end of file is reached, set 'uncommitted' 745 // mode, thus allowing an immediate write without 746 // an intervening seek. 747 _M_set_buffer(-1); 748 _M_reading = false; 749 } 750 } 751 else 752 __ret += __streambuf_type::xsgetn(__s, __n); 753 754 return __ret; 755 } 756 757 template<typename _CharT, typename _Traits> 758 streamsize 759 basic_filebuf<_CharT, _Traits>:: 760 xsputn(const _CharT* __s, streamsize __n) 761 { 762 streamsize __ret = 0; 763 // Optimization in the always_noconv() case, to be generalized in the 764 // future: when __n is larger than the available capacity we write 765 // directly instead of using the buffer. 766 const bool __testout = (_M_mode & ios_base::out 767 || _M_mode & ios_base::app); 768 if (__check_facet(_M_codecvt).always_noconv() 769 && __testout && !_M_reading) 770 { 771 streamsize __bufavail = this->epptr() - this->pptr(); 772 773 // Don't mistake 'uncommitted' mode buffered with unbuffered. 774 if (!_M_writing && _M_buf_size > 1) 775 __bufavail = _M_buf_size - 1; 776 777 if (__n >= __bufavail) 778 { 779 const streamsize __buffill = this->pptr() - this->pbase(); 780 const char* __buf = reinterpret_cast<const char*>(this->pbase()); 781 __ret = _M_file.xsputn_2(__buf, __buffill, 782 reinterpret_cast<const char*>(__s), 783 __n); 784 if (__ret == __buffill + __n) 785 { 786 _M_set_buffer(0); 787 _M_writing = true; 788 } 789 if (__ret > __buffill) 790 __ret -= __buffill; 791 else 792 __ret = 0; 793 } 794 else 795 __ret = __streambuf_type::xsputn(__s, __n); 796 } 797 else 798 __ret = __streambuf_type::xsputn(__s, __n); 799 return __ret; 800 } 801 802 template<typename _CharT, typename _Traits> 803 typename basic_filebuf<_CharT, _Traits>::__streambuf_type* 804 basic_filebuf<_CharT, _Traits>:: 805 setbuf(char_type* __s, streamsize __n) 806 { 807 if (!this->is_open()) 808 { 809 if (__s == 0 && __n == 0) 810 _M_buf_size = 1; 811 else if (__s && __n > 0) 812 { 813 // This is implementation-defined behavior, and assumes that 814 // an external char_type array of length __n exists and has 815 // been pre-allocated. If this is not the case, things will 816 // quickly blow up. When __n > 1, __n - 1 positions will be 817 // used for the get area, __n - 1 for the put area and 1 818 // position to host the overflow char of a full put area. 819 // When __n == 1, 1 position will be used for the get area 820 // and 0 for the put area, as in the unbuffered case above. 821 _M_buf = __s; 822 _M_buf_size = __n; 823 } 824 } 825 return this; 826 } 827 828 829 // According to 27.8.1.4 p11 - 13, seekoff should ignore the last 830 // argument (of type openmode). 831 template<typename _CharT, typename _Traits> 832 typename basic_filebuf<_CharT, _Traits>::pos_type 833 basic_filebuf<_CharT, _Traits>:: 834 seekoff(off_type __off, ios_base::seekdir __way, ios_base::openmode) 835 { 836 int __width = 0; 837 if (_M_codecvt) 838 __width = _M_codecvt->encoding(); 839 if (__width < 0) 840 __width = 0; 841 842 pos_type __ret = pos_type(off_type(-1)); 843 const bool __testfail = __off != 0 && __width <= 0; 844 if (this->is_open() && !__testfail) 845 { 846 // tellg and tellp queries do not affect any state, unless 847 // ! always_noconv and the put sequence is not empty. 848 // In that case, determining the position requires converting the 849 // put sequence. That doesn't use ext_buf, so requires a flush. 850 bool __no_movement = __way == ios_base::cur && __off == 0 851 && (!_M_writing || _M_codecvt->always_noconv()); 852 853 // Ditch any pback buffers to avoid confusion. 854 if (!__no_movement) 855 _M_destroy_pback(); 856 857 // Correct state at destination. Note that this is the correct 858 // state for the current position during output, because 859 // codecvt::unshift() returns the state to the initial state. 860 // This is also the correct state at the end of the file because 861 // an unshift sequence should have been written at the end. 862 __state_type __state = _M_state_beg; 863 off_type __computed_off = __off * __width; 864 if (_M_reading && __way == ios_base::cur) 865 { 866 __state = _M_state_last; 867 __computed_off += _M_get_ext_pos(__state); 868 } 869 if (!__no_movement) 870 __ret = _M_seek(__computed_off, __way, __state); 871 else 872 { 873 if (_M_writing) 874 __computed_off = this->pptr() - this->pbase(); 875 876 off_type __file_off = _M_file.seekoff(0, ios_base::cur); 877 if (__file_off != off_type(-1)) 878 { 879 __ret = __file_off + __computed_off; 880 __ret.state(__state); 881 } 882 } 883 } 884 return __ret; 885 } 886 887 // _GLIBCXX_RESOLVE_LIB_DEFECTS 888 // 171. Strange seekpos() semantics due to joint position 889 // According to the resolution of DR 171, seekpos should ignore the last 890 // argument (of type openmode). 891 template<typename _CharT, typename _Traits> 892 typename basic_filebuf<_CharT, _Traits>::pos_type 893 basic_filebuf<_CharT, _Traits>:: 894 seekpos(pos_type __pos, ios_base::openmode) 895 { 896 pos_type __ret = pos_type(off_type(-1)); 897 if (this->is_open()) 898 { 899 // Ditch any pback buffers to avoid confusion. 900 _M_destroy_pback(); 901 __ret = _M_seek(off_type(__pos), ios_base::beg, __pos.state()); 902 } 903 return __ret; 904 } 905 906 template<typename _CharT, typename _Traits> 907 typename basic_filebuf<_CharT, _Traits>::pos_type 908 basic_filebuf<_CharT, _Traits>:: 909 _M_seek(off_type __off, ios_base::seekdir __way, __state_type __state) 910 { 911 pos_type __ret = pos_type(off_type(-1)); 912 if (_M_terminate_output()) 913 { 914 off_type __file_off = _M_file.seekoff(__off, __way); 915 if (__file_off != off_type(-1)) 916 { 917 _M_reading = false; 918 _M_writing = false; 919 _M_ext_next = _M_ext_end = _M_ext_buf; 920 _M_set_buffer(-1); 921 _M_state_cur = __state; 922 __ret = __file_off; 923 __ret.state(_M_state_cur); 924 } 925 } 926 return __ret; 927 } 928 929 // Returns the distance from the end of the ext buffer to the point 930 // corresponding to gptr(). This is a negative value. Updates __state 931 // from eback() correspondence to gptr(). 932 template<typename _CharT, typename _Traits> 933 int basic_filebuf<_CharT, _Traits>:: 934 _M_get_ext_pos(__state_type& __state) 935 { 936 if (_M_codecvt->always_noconv()) 937 return this->gptr() - this->egptr(); 938 else 939 { 940 // Calculate offset from _M_ext_buf that corresponds to 941 // gptr(). Precondition: __state == _M_state_last, which 942 // corresponds to eback(). 943 const int __gptr_off = 944 _M_codecvt->length(__state, _M_ext_buf, _M_ext_next, 945 this->gptr() - this->eback()); 946 return _M_ext_buf + __gptr_off - _M_ext_end; 947 } 948 } 949 950 template<typename _CharT, typename _Traits> 951 bool 952 basic_filebuf<_CharT, _Traits>:: 953 _M_terminate_output() 954 { 955 // Part one: update the output sequence. 956 bool __testvalid = true; 957 if (this->pbase() < this->pptr()) 958 { 959 const int_type __tmp = this->overflow(); 960 if (traits_type::eq_int_type(__tmp, traits_type::eof())) 961 __testvalid = false; 962 } 963 964 // Part two: output unshift sequence. 965 if (_M_writing && !__check_facet(_M_codecvt).always_noconv() 966 && __testvalid) 967 { 968 // Note: this value is arbitrary, since there is no way to 969 // get the length of the unshift sequence from codecvt, 970 // without calling unshift. 971 const size_t __blen = 128; 972 char __buf[__blen]; 973 codecvt_base::result __r; 974 streamsize __ilen = 0; 975 976 do 977 { 978 char* __next; 979 __r = _M_codecvt->unshift(_M_state_cur, __buf, 980 __buf + __blen, __next); 981 if (__r == codecvt_base::error) 982 __testvalid = false; 983 else if (__r == codecvt_base::ok || 984 __r == codecvt_base::partial) 985 { 986 __ilen = __next - __buf; 987 if (__ilen > 0) 988 { 989 const streamsize __elen = _M_file.xsputn(__buf, __ilen); 990 if (__elen != __ilen) 991 __testvalid = false; 992 } 993 } 994 } 995 while (__r == codecvt_base::partial && __ilen > 0 && __testvalid); 996 997 if (__testvalid) 998 { 999 // This second call to overflow() is required by the standard, 1000 // but it's not clear why it's needed, since the output buffer 1001 // should be empty by this point (it should have been emptied 1002 // in the first call to overflow()). 1003 const int_type __tmp = this->overflow(); 1004 if (traits_type::eq_int_type(__tmp, traits_type::eof())) 1005 __testvalid = false; 1006 } 1007 } 1008 return __testvalid; 1009 } 1010 1011 template<typename _CharT, typename _Traits> 1012 int 1013 basic_filebuf<_CharT, _Traits>:: 1014 sync() 1015 { 1016 // Make sure that the internal buffer resyncs its idea of 1017 // the file position with the external file. 1018 int __ret = 0; 1019 if (this->pbase() < this->pptr()) 1020 { 1021 const int_type __tmp = this->overflow(); 1022 if (traits_type::eq_int_type(__tmp, traits_type::eof())) 1023 __ret = -1; 1024 } 1025 return __ret; 1026 } 1027 1028 template<typename _CharT, typename _Traits> 1029 void 1030 basic_filebuf<_CharT, _Traits>:: 1031 imbue(const locale& __loc) 1032 { 1033 bool __testvalid = true; 1034 1035 const __codecvt_type* const _M_codecvt_tmp 1036 = __try_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 #pragma GCC diagnostic pop 1103 #endif
