1// File based streams -*- C++ -*- 
2 
3// Copyright (C) 1997-2019 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 
43namespace 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(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 
1103