| blob | 12ea977b997445cbc954d643c380691527656f59 |
1 // File based streams -*- C++ -*-
3 // Copyright (C) 1997-2017 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.
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.
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.
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/>.
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 */
30 //
31 // ISO C++ 14882: 27.8 File-based streams
32 //
34 #ifndef _FSTREAM_TCC
35 #define _FSTREAM_TCC 1
37 #pragma GCC system_header
39 #include <bits/cxxabi_forced.h>
40 #include <bits/move.h> // for swap
42 namespace std _GLIBCXX_VISIBILITY(default)
43 {
44 _GLIBCXX_BEGIN_NAMESPACE_VERSION
46 template<typename _CharT, typename _Traits>
47 void
48 basic_filebuf<_CharT, _Traits>::
49 _M_allocate_internal_buffer()
50 {
51 // Allocate internal buffer only if one doesn't already exist
52 // (either allocated or provided by the user via setbuf).
53 if (!_M_buf_allocated && !_M_buf)
54 {
55 _M_buf = new char_type[_M_buf_size];
56 _M_buf_allocated = true;
57 }
58 }
60 template<typename _CharT, typename _Traits>
61 void
62 basic_filebuf<_CharT, _Traits>::
63 _M_destroy_internal_buffer() throw()
64 {
65 if (_M_buf_allocated)
66 {
67 delete [] _M_buf;
68 _M_buf = 0;
69 _M_buf_allocated = false;
70 }
71 delete [] _M_ext_buf;
72 _M_ext_buf = 0;
73 _M_ext_buf_size = 0;
74 _M_ext_next = 0;
75 _M_ext_end = 0;
76 }
78 template<typename _CharT, typename _Traits>
79 basic_filebuf<_CharT, _Traits>::
80 basic_filebuf() : __streambuf_type(), _M_lock(), _M_file(&_M_lock),
81 _M_mode(ios_base::openmode(0)), _M_state_beg(), _M_state_cur(),
82 _M_state_last(), _M_buf(0), _M_buf_size(BUFSIZ),
83 _M_buf_allocated(false), _M_reading(false), _M_writing(false), _M_pback(),
84 _M_pback_cur_save(0), _M_pback_end_save(0), _M_pback_init(false),
85 _M_codecvt(0), _M_ext_buf(0), _M_ext_buf_size(0), _M_ext_next(0),
86 _M_ext_end(0)
87 {
88 if (has_facet<__codecvt_type>(this->_M_buf_locale))
89 _M_codecvt = &use_facet<__codecvt_type>(this->_M_buf_locale);
90 }
92 #if __cplusplus >= 201103L
93 template<typename _CharT, typename _Traits>
94 basic_filebuf<_CharT, _Traits>::
95 basic_filebuf(basic_filebuf&& __rhs)
96 : __streambuf_type(__rhs),
97 _M_lock(), _M_file(std::move(__rhs._M_file), &_M_lock),
98 _M_mode(std::__exchange(__rhs._M_mode, ios_base::openmode(0))),
99 _M_state_beg(std::move(__rhs._M_state_beg)),
100 _M_state_cur(std::move(__rhs._M_state_cur)),
101 _M_state_last(std::move(__rhs._M_state_last)),
102 _M_buf(std::__exchange(__rhs._M_buf, nullptr)),
103 _M_buf_size(std::__exchange(__rhs._M_buf_size, 1)),
104 _M_buf_allocated(std::__exchange(__rhs._M_buf_allocated, false)),
105 _M_reading(std::__exchange(__rhs._M_reading, false)),
106 _M_writing(std::__exchange(__rhs._M_writing, false)),
107 _M_pback(__rhs._M_pback),
108 _M_pback_cur_save(std::__exchange(__rhs._M_pback_cur_save, nullptr)),
109 _M_pback_end_save(std::__exchange(__rhs._M_pback_end_save, nullptr)),
110 _M_pback_init(std::__exchange(__rhs._M_pback_init, false)),
111 _M_codecvt(__rhs._M_codecvt),
112 _M_ext_buf(std::__exchange(__rhs._M_ext_buf, nullptr)),
113 _M_ext_buf_size(std::__exchange(__rhs._M_ext_buf_size, 0)),
114 _M_ext_next(std::__exchange(__rhs._M_ext_next, nullptr)),
115 _M_ext_end(std::__exchange(__rhs._M_ext_end, nullptr))
116 {
117 __rhs._M_set_buffer(-1);
118 __rhs._M_state_last = __rhs._M_state_cur = __rhs._M_state_beg;
119 }
121 template<typename _CharT, typename _Traits>
122 basic_filebuf<_CharT, _Traits>&
123 basic_filebuf<_CharT, _Traits>::
124 operator=(basic_filebuf&& __rhs)
125 {
126 this->close();
127 __streambuf_type::operator=(__rhs);
128 _M_file.swap(__rhs._M_file);
129 _M_mode = std::__exchange(__rhs._M_mode, ios_base::openmode(0));
130 _M_state_beg = std::move(__rhs._M_state_beg);
131 _M_state_cur = std::move(__rhs._M_state_cur);
132 _M_state_last = std::move(__rhs._M_state_last);
133 _M_buf = std::__exchange(__rhs._M_buf, nullptr);
134 _M_buf_size = std::__exchange(__rhs._M_buf_size, 1);
135 _M_buf_allocated = std::__exchange(__rhs._M_buf_allocated, false);
136 _M_ext_buf = std::__exchange(__rhs._M_ext_buf, nullptr);
137 _M_ext_buf_size = std::__exchange(__rhs._M_ext_buf_size, 0);
138 _M_ext_next = std::__exchange(__rhs._M_ext_next, nullptr);
139 _M_ext_end = std::__exchange(__rhs._M_ext_end, nullptr);
140 _M_reading = std::__exchange(__rhs._M_reading, false);
141 _M_writing = std::__exchange(__rhs._M_writing, false);
142 _M_pback_cur_save = std::__exchange(__rhs._M_pback_cur_save, nullptr);
143 _M_pback_end_save = std::__exchange(__rhs._M_pback_end_save, nullptr);
144 _M_pback_init = std::__exchange(__rhs._M_pback_init, false);
145 __rhs._M_set_buffer(-1);
146 __rhs._M_state_last = __rhs._M_state_cur = __rhs._M_state_beg;
147 return *this;
148 }
150 template<typename _CharT, typename _Traits>
151 void
152 basic_filebuf<_CharT, _Traits>::
153 swap(basic_filebuf& __rhs)
154 {
155 __streambuf_type::swap(__rhs);
156 _M_file.swap(__rhs._M_file);
157 std::swap(_M_mode, __rhs._M_mode);
158 std::swap(_M_state_beg, __rhs._M_state_beg);
159 std::swap(_M_state_cur, __rhs._M_state_cur);
160 std::swap(_M_state_last, __rhs._M_state_last);
161 std::swap(_M_buf, __rhs._M_buf);
162 std::swap(_M_buf_size, __rhs._M_buf_size);
163 std::swap(_M_buf_allocated, __rhs._M_buf_allocated);
164 std::swap(_M_ext_buf, __rhs._M_ext_buf);
165 std::swap(_M_ext_buf_size, __rhs._M_ext_buf_size);
166 std::swap(_M_ext_next, __rhs._M_ext_next);
167 std::swap(_M_ext_end, __rhs._M_ext_end);
168 std::swap(_M_reading, __rhs._M_reading);
169 std::swap(_M_writing, __rhs._M_writing);
170 std::swap(_M_pback_cur_save, __rhs._M_pback_cur_save);
171 std::swap(_M_pback_end_save, __rhs._M_pback_end_save);
172 std::swap(_M_pback_init, __rhs._M_pback_init);
173 }
174 #endif
176 template<typename _CharT, typename _Traits>
177 typename basic_filebuf<_CharT, _Traits>::__filebuf_type*
178 basic_filebuf<_CharT, _Traits>::
179 open(const char* __s, ios_base::openmode __mode)
180 {
181 __filebuf_type *__ret = 0;
182 if (!this->is_open())
183 {
184 _M_file.open(__s, __mode);
185 if (this->is_open())
186 {
187 _M_allocate_internal_buffer();
188 _M_mode = __mode;
190 // Setup initial buffer to 'uncommitted' mode.
191 _M_reading = false;
192 _M_writing = false;
193 _M_set_buffer(-1);
195 // Reset to initial state.
196 _M_state_last = _M_state_cur = _M_state_beg;
198 // 27.8.1.3,4
199 if ((__mode & ios_base::ate)
200 && this->seekoff(0, ios_base::end, __mode)
201 == pos_type(off_type(-1)))
202 this->close();
203 else
204 __ret = this;
205 }
206 }
207 return __ret;
208 }
210 template<typename _CharT, typename _Traits>
211 typename basic_filebuf<_CharT, _Traits>::__filebuf_type*
212 basic_filebuf<_CharT, _Traits>::
213 close()
214 {
215 if (!this->is_open())
216 return 0;
218 bool __testfail = false;
219 {
220 // NB: Do this here so that re-opened filebufs will be cool...
221 struct __close_sentry
222 {
223 basic_filebuf *__fb;
224 __close_sentry (basic_filebuf *__fbi): __fb(__fbi) { }
225 ~__close_sentry ()
226 {
227 __fb->_M_mode = ios_base::openmode(0);
228 __fb->_M_pback_init = false;
229 __fb->_M_destroy_internal_buffer();
230 __fb->_M_reading = false;
231 __fb->_M_writing = false;
232 __fb->_M_set_buffer(-1);
233 __fb->_M_state_last = __fb->_M_state_cur = __fb->_M_state_beg;
234 }
235 } __cs (this);
237 __try
238 {
239 if (!_M_terminate_output())
240 __testfail = true;
241 }
242 __catch(__cxxabiv1::__forced_unwind&)
243 {
244 _M_file.close();
245 __throw_exception_again;
246 }
247 __catch(...)
248 { __testfail = true; }
249 }
251 if (!_M_file.close())
252 __testfail = true;
254 if (__testfail)
255 return 0;
256 else
257 return this;
258 }
260 template<typename _CharT, typename _Traits>
261 streamsize
262 basic_filebuf<_CharT, _Traits>::
263 showmanyc()
264 {
265 streamsize __ret = -1;
266 const bool __testin = _M_mode & ios_base::in;
267 if (__testin && this->is_open())
268 {
269 // For a stateful encoding (-1) the pending sequence might be just
270 // shift and unshift prefixes with no actual character.
271 __ret = this->egptr() - this->gptr();
273 #if _GLIBCXX_HAVE_DOS_BASED_FILESYSTEM
274 // About this workaround, see libstdc++/20806.
275 const bool __testbinary = _M_mode & ios_base::binary;
276 if (__check_facet(_M_codecvt).encoding() >= 0
277 && __testbinary)
278 #else
279 if (__check_facet(_M_codecvt).encoding() >= 0)
280 #endif
281 __ret += _M_file.showmanyc() / _M_codecvt->max_length();
282 }
283 return __ret;
284 }
286 template<typename _CharT, typename _Traits>
287 typename basic_filebuf<_CharT, _Traits>::int_type
288 basic_filebuf<_CharT, _Traits>::
289 underflow()
290 {
291 int_type __ret = traits_type::eof();
292 const bool __testin = _M_mode & ios_base::in;
293 if (__testin)
294 {
295 if (_M_writing)
296 {
297 if (overflow() == traits_type::eof())
298 return __ret;
299 _M_set_buffer(-1);
300 _M_writing = false;
301 }
302 // Check for pback madness, and if so switch back to the
303 // normal buffers and jet outta here before expensive
304 // fileops happen...
305 _M_destroy_pback();
307 if (this->gptr() < this->egptr())
308 return traits_type::to_int_type(*this->gptr());
310 // Get and convert input sequence.
311 const size_t __buflen = _M_buf_size > 1 ? _M_buf_size - 1 : 1;
313 // Will be set to true if ::read() returns 0 indicating EOF.
314 bool __got_eof = false;
315 // Number of internal characters produced.
316 streamsize __ilen = 0;
317 codecvt_base::result __r = codecvt_base::ok;
318 if (__check_facet(_M_codecvt).always_noconv())
319 {
320 __ilen = _M_file.xsgetn(reinterpret_cast<char*>(this->eback()),
321 __buflen);
322 if (__ilen == 0)
323 __got_eof = true;
324 }
325 else
326 {
327 // Worst-case number of external bytes.
328 // XXX Not done encoding() == -1.
329 const int __enc = _M_codecvt->encoding();
330 streamsize __blen; // Minimum buffer size.
331 streamsize __rlen; // Number of chars to read.
332 if (__enc > 0)
333 __blen = __rlen = __buflen * __enc;
334 else
335 {
336 __blen = __buflen + _M_codecvt->max_length() - 1;
337 __rlen = __buflen;
338 }
339 const streamsize __remainder = _M_ext_end - _M_ext_next;
340 __rlen = __rlen > __remainder ? __rlen - __remainder : 0;
342 // An imbue in 'read' mode implies first converting the external
343 // chars already present.
344 if (_M_reading && this->egptr() == this->eback() && __remainder)
345 __rlen = 0;
347 // Allocate buffer if necessary and move unconverted
348 // bytes to front.
349 if (_M_ext_buf_size < __blen)
350 {
351 char* __buf = new char[__blen];
352 if (__remainder)
353 __builtin_memcpy(__buf, _M_ext_next, __remainder);
355 delete [] _M_ext_buf;
356 _M_ext_buf = __buf;
357 _M_ext_buf_size = __blen;
358 }
359 else if (__remainder)
360 __builtin_memmove(_M_ext_buf, _M_ext_next, __remainder);
362 _M_ext_next = _M_ext_buf;
363 _M_ext_end = _M_ext_buf + __remainder;
364 _M_state_last = _M_state_cur;
366 do
367 {
368 if (__rlen > 0)
369 {
370 // Sanity check!
371 // This may fail if the return value of
372 // codecvt::max_length() is bogus.
373 if (_M_ext_end - _M_ext_buf + __rlen > _M_ext_buf_size)
374 {
375 __throw_ios_failure(__N("basic_filebuf::underflow "
376 "codecvt::max_length() "
377 "is not valid"));
378 }
379 streamsize __elen = _M_file.xsgetn(_M_ext_end, __rlen);
380 if (__elen == 0)
381 __got_eof = true;
382 else if (__elen == -1)
383 break;
384 _M_ext_end += __elen;
385 }
387 char_type* __iend = this->eback();
388 if (_M_ext_next < _M_ext_end)
389 __r = _M_codecvt->in(_M_state_cur, _M_ext_next,
390 _M_ext_end, _M_ext_next,
391 this->eback(),
392 this->eback() + __buflen, __iend);
393 if (__r == codecvt_base::noconv)
394 {
395 size_t __avail = _M_ext_end - _M_ext_buf;
396 __ilen = std::min(__avail, __buflen);
397 traits_type::copy(this->eback(),
398 reinterpret_cast<char_type*>
399 (_M_ext_buf), __ilen);
400 _M_ext_next = _M_ext_buf + __ilen;
401 }
402 else
403 __ilen = __iend - this->eback();
405 // _M_codecvt->in may return error while __ilen > 0: this is
406 // ok, and actually occurs in case of mixed encodings (e.g.,
407 // XML files).
408 if (__r == codecvt_base::error)
409 break;
411 __rlen = 1;
412 }
413 while (__ilen == 0 && !__got_eof);
414 }
416 if (__ilen > 0)
417 {
418 _M_set_buffer(__ilen);
419 _M_reading = true;
420 __ret = traits_type::to_int_type(*this->gptr());
421 }
422 else if (__got_eof)
423 {
424 // If the actual end of file is reached, set 'uncommitted'
425 // mode, thus allowing an immediate write without an
426 // intervening seek.
427 _M_set_buffer(-1);
428 _M_reading = false;
429 // However, reaching it while looping on partial means that
430 // the file has got an incomplete character.
431 if (__r == codecvt_base::partial)
432 __throw_ios_failure(__N("basic_filebuf::underflow "
433 "incomplete character in file"));
434 }
435 else if (__r == codecvt_base::error)
436 __throw_ios_failure(__N("basic_filebuf::underflow "
437 "invalid byte sequence in file"));
438 else
439 __throw_ios_failure(__N("basic_filebuf::underflow "
440 "error reading the file"));
441 }
442 return __ret;
443 }
445 template<typename _CharT, typename _Traits>
446 typename basic_filebuf<_CharT, _Traits>::int_type
447 basic_filebuf<_CharT, _Traits>::
448 pbackfail(int_type __i)
449 {
450 int_type __ret = traits_type::eof();
451 const bool __testin = _M_mode & ios_base::in;
452 if (__testin)
453 {
454 if (_M_writing)
455 {
456 if (overflow() == traits_type::eof())
457 return __ret;
458 _M_set_buffer(-1);
459 _M_writing = false;
460 }
461 // Remember whether the pback buffer is active, otherwise below
462 // we may try to store in it a second char (libstdc++/9761).
463 const bool __testpb = _M_pback_init;
464 const bool __testeof = traits_type::eq_int_type(__i, __ret);
465 int_type __tmp;
466 if (this->eback() < this->gptr())
467 {
468 this->gbump(-1);
469 __tmp = traits_type::to_int_type(*this->gptr());
470 }
471 else if (this->seekoff(-1, ios_base::cur) != pos_type(off_type(-1)))
472 {
473 __tmp = this->underflow();
474 if (traits_type::eq_int_type(__tmp, __ret))
475 return __ret;
476 }
477 else
478 {
479 // At the beginning of the buffer, need to make a
480 // putback position available. But the seek may fail
481 // (f.i., at the beginning of a file, see
482 // libstdc++/9439) and in that case we return
483 // traits_type::eof().
484 return __ret;
485 }
487 // Try to put back __i into input sequence in one of three ways.
488 // Order these tests done in is unspecified by the standard.
489 if (!__testeof && traits_type::eq_int_type(__i, __tmp))
490 __ret = __i;
491 else if (__testeof)
492 __ret = traits_type::not_eof(__i);
493 else if (!__testpb)
494 {
495 _M_create_pback();
496 _M_reading = true;
497 *this->gptr() = traits_type::to_char_type(__i);
498 __ret = __i;
499 }
500 }
501 return __ret;
502 }
504 template<typename _CharT, typename _Traits>
505 typename basic_filebuf<_CharT, _Traits>::int_type
506 basic_filebuf<_CharT, _Traits>::
507 overflow(int_type __c)
508 {
509 int_type __ret = traits_type::eof();
510 const bool __testeof = traits_type::eq_int_type(__c, __ret);
511 const bool __testout = (_M_mode & ios_base::out
512 || _M_mode & ios_base::app);
513 if (__testout)
514 {
515 if (_M_reading)
516 {
517 _M_destroy_pback();
518 const int __gptr_off = _M_get_ext_pos(_M_state_last);
519 if (_M_seek(__gptr_off, ios_base::cur, _M_state_last)
520 == pos_type(off_type(-1)))
521 return __ret;
522 }
523 if (this->pbase() < this->pptr())
524 {
525 // If appropriate, append the overflow char.
526 if (!__testeof)
527 {
528 *this->pptr() = traits_type::to_char_type(__c);
529 this->pbump(1);
530 }
532 // Convert pending sequence to external representation,
533 // and output.
534 if (_M_convert_to_external(this->pbase(),
535 this->pptr() - this->pbase()))
536 {
537 _M_set_buffer(0);
538 __ret = traits_type::not_eof(__c);
539 }
540 }
541 else if (_M_buf_size > 1)
542 {
543 // Overflow in 'uncommitted' mode: set _M_writing, set
544 // the buffer to the initial 'write' mode, and put __c
545 // into the buffer.
546 _M_set_buffer(0);
547 _M_writing = true;
548 if (!__testeof)
549 {
550 *this->pptr() = traits_type::to_char_type(__c);
551 this->pbump(1);
552 }
553 __ret = traits_type::not_eof(__c);
554 }
555 else
556 {
557 // Unbuffered.
558 char_type __conv = traits_type::to_char_type(__c);
559 if (__testeof || _M_convert_to_external(&__conv, 1))
560 {
561 _M_writing = true;
562 __ret = traits_type::not_eof(__c);
563 }
564 }
565 }
566 return __ret;
567 }
569 template<typename _CharT, typename _Traits>
570 bool
571 basic_filebuf<_CharT, _Traits>::
572 _M_convert_to_external(_CharT* __ibuf, streamsize __ilen)
573 {
574 // Sizes of external and pending output.
575 streamsize __elen;
576 streamsize __plen;
577 if (__check_facet(_M_codecvt).always_noconv())
578 {
579 __elen = _M_file.xsputn(reinterpret_cast<char*>(__ibuf), __ilen);
580 __plen = __ilen;
581 }
582 else
583 {
584 // Worst-case number of external bytes needed.
585 // XXX Not done encoding() == -1.
586 streamsize __blen = __ilen * _M_codecvt->max_length();
587 char* __buf = static_cast<char*>(__builtin_alloca(__blen));
589 char* __bend;
590 const char_type* __iend;
591 codecvt_base::result __r;
592 __r = _M_codecvt->out(_M_state_cur, __ibuf, __ibuf + __ilen,
593 __iend, __buf, __buf + __blen, __bend);
595 if (__r == codecvt_base::ok || __r == codecvt_base::partial)
596 __blen = __bend - __buf;
597 else if (__r == codecvt_base::noconv)
598 {
599 // Same as the always_noconv case above.
600 __buf = reinterpret_cast<char*>(__ibuf);
601 __blen = __ilen;
602 }
603 else
604 __throw_ios_failure(__N("basic_filebuf::_M_convert_to_external "
605 "conversion error"));
607 __elen = _M_file.xsputn(__buf, __blen);
608 __plen = __blen;
610 // Try once more for partial conversions.
611 if (__r == codecvt_base::partial && __elen == __plen)
612 {
613 const char_type* __iresume = __iend;
614 streamsize __rlen = this->pptr() - __iend;
615 __r = _M_codecvt->out(_M_state_cur, __iresume,
616 __iresume + __rlen, __iend, __buf,
617 __buf + __blen, __bend);
618 if (__r != codecvt_base::error)
619 {
620 __rlen = __bend - __buf;
621 __elen = _M_file.xsputn(__buf, __rlen);
622 __plen = __rlen;
623 }
624 else
625 __throw_ios_failure(__N("basic_filebuf::_M_convert_to_external "
626 "conversion error"));
627 }
628 }
629 return __elen == __plen;
630 }
632 template<typename _CharT, typename _Traits>
633 streamsize
634 basic_filebuf<_CharT, _Traits>::
635 xsgetn(_CharT* __s, streamsize __n)
636 {
637 // Clear out pback buffer before going on to the real deal...
638 streamsize __ret = 0;
639 if (_M_pback_init)
640 {
641 if (__n > 0 && this->gptr() == this->eback())
642 {
643 *__s++ = *this->gptr(); // emulate non-underflowing sbumpc
644 this->gbump(1);
645 __ret = 1;
646 --__n;
647 }
648 _M_destroy_pback();
649 }
650 else if (_M_writing)
651 {
652 if (overflow() == traits_type::eof())
653 return __ret;
654 _M_set_buffer(-1);
655 _M_writing = false;
656 }
658 // Optimization in the always_noconv() case, to be generalized in the
659 // future: when __n > __buflen we read directly instead of using the
660 // buffer repeatedly.
661 const bool __testin = _M_mode & ios_base::in;
662 const streamsize __buflen = _M_buf_size > 1 ? _M_buf_size - 1 : 1;
664 if (__n > __buflen && __check_facet(_M_codecvt).always_noconv()
665 && __testin)
666 {
667 // First, copy the chars already present in the buffer.
668 const streamsize __avail = this->egptr() - this->gptr();
669 if (__avail != 0)
670 {
671 traits_type::copy(__s, this->gptr(), __avail);
672 __s += __avail;
673 this->setg(this->eback(), this->gptr() + __avail, this->egptr());
674 __ret += __avail;
675 __n -= __avail;
676 }
678 // Need to loop in case of short reads (relatively common
679 // with pipes).
680 streamsize __len;
681 for (;;)
682 {
683 __len = _M_file.xsgetn(reinterpret_cast<char*>(__s), __n);
684 if (__len == -1)
685 __throw_ios_failure(__N("basic_filebuf::xsgetn "
686 "error reading the file"));
687 if (__len == 0)
688 break;
690 __n -= __len;
691 __ret += __len;
692 if (__n == 0)
693 break;
695 __s += __len;
696 }
698 if (__n == 0)
699 {
700 // Set _M_reading. Buffer is already in initial 'read' mode.
701 _M_reading = true;
702 }
703 else if (__len == 0)
704 {
705 // If end of file is reached, set 'uncommitted'
706 // mode, thus allowing an immediate write without
707 // an intervening seek.
708 _M_set_buffer(-1);
709 _M_reading = false;
710 }
711 }
712 else
713 __ret += __streambuf_type::xsgetn(__s, __n);
715 return __ret;
716 }
718 template<typename _CharT, typename _Traits>
719 streamsize
720 basic_filebuf<_CharT, _Traits>::
721 xsputn(const _CharT* __s, streamsize __n)
722 {
723 streamsize __ret = 0;
724 // Optimization in the always_noconv() case, to be generalized in the
725 // future: when __n is sufficiently large we write directly instead of
726 // using the buffer.
727 const bool __testout = (_M_mode & ios_base::out
728 || _M_mode & ios_base::app);
729 if (__check_facet(_M_codecvt).always_noconv()
730 && __testout && !_M_reading)
731 {
732 // Measurement would reveal the best choice.
733 const streamsize __chunk = 1ul << 10;
734 streamsize __bufavail = this->epptr() - this->pptr();
736 // Don't mistake 'uncommitted' mode buffered with unbuffered.
737 if (!_M_writing && _M_buf_size > 1)
738 __bufavail = _M_buf_size - 1;
740 const streamsize __limit = std::min(__chunk, __bufavail);
741 if (__n >= __limit)
742 {
743 const streamsize __buffill = this->pptr() - this->pbase();
744 const char* __buf = reinterpret_cast<const char*>(this->pbase());
745 __ret = _M_file.xsputn_2(__buf, __buffill,
746 reinterpret_cast<const char*>(__s),
747 __n);
748 if (__ret == __buffill + __n)
749 {
750 _M_set_buffer(0);
751 _M_writing = true;
752 }
753 if (__ret > __buffill)
754 __ret -= __buffill;
755 else
756 __ret = 0;
757 }
758 else
759 __ret = __streambuf_type::xsputn(__s, __n);
760 }
761 else
762 __ret = __streambuf_type::xsputn(__s, __n);
763 return __ret;
764 }
766 template<typename _CharT, typename _Traits>
767 typename basic_filebuf<_CharT, _Traits>::__streambuf_type*
768 basic_filebuf<_CharT, _Traits>::
769 setbuf(char_type* __s, streamsize __n)
770 {
771 if (!this->is_open())
772 {
773 if (__s == 0 && __n == 0)
774 _M_buf_size = 1;
775 else if (__s && __n > 0)
776 {
777 // This is implementation-defined behavior, and assumes that
778 // an external char_type array of length __n exists and has
779 // been pre-allocated. If this is not the case, things will
780 // quickly blow up. When __n > 1, __n - 1 positions will be
781 // used for the get area, __n - 1 for the put area and 1
782 // position to host the overflow char of a full put area.
783 // When __n == 1, 1 position will be used for the get area
784 // and 0 for the put area, as in the unbuffered case above.
785 _M_buf = __s;
786 _M_buf_size = __n;
787 }
788 }
789 return this;
790 }
793 // According to 27.8.1.4 p11 - 13, seekoff should ignore the last
794 // argument (of type openmode).
795 template<typename _CharT, typename _Traits>
796 typename basic_filebuf<_CharT, _Traits>::pos_type
797 basic_filebuf<_CharT, _Traits>::
798 seekoff(off_type __off, ios_base::seekdir __way, ios_base::openmode)
799 {
800 int __width = 0;
801 if (_M_codecvt)
802 __width = _M_codecvt->encoding();
803 if (__width < 0)
804 __width = 0;
806 pos_type __ret = pos_type(off_type(-1));
807 const bool __testfail = __off != 0 && __width <= 0;
808 if (this->is_open() && !__testfail)
809 {
810 // tellg and tellp queries do not affect any state, unless
811 // ! always_noconv and the put sequence is not empty.
812 // In that case, determining the position requires converting the
813 // put sequence. That doesn't use ext_buf, so requires a flush.
814 bool __no_movement = __way == ios_base::cur && __off == 0
815 && (!_M_writing || _M_codecvt->always_noconv());
817 // Ditch any pback buffers to avoid confusion.
818 if (!__no_movement)
819 _M_destroy_pback();
821 // Correct state at destination. Note that this is the correct
822 // state for the current position during output, because
823 // codecvt::unshift() returns the state to the initial state.
824 // This is also the correct state at the end of the file because
825 // an unshift sequence should have been written at the end.
826 __state_type __state = _M_state_beg;
827 off_type __computed_off = __off * __width;
828 if (_M_reading && __way == ios_base::cur)
829 {
830 __state = _M_state_last;
831 __computed_off += _M_get_ext_pos(__state);
832 }
833 if (!__no_movement)
834 __ret = _M_seek(__computed_off, __way, __state);
835 else
836 {
837 if (_M_writing)
838 __computed_off = this->pptr() - this->pbase();
840 off_type __file_off = _M_file.seekoff(0, ios_base::cur);
841 if (__file_off != off_type(-1))
842 {
843 __ret = __file_off + __computed_off;
844 __ret.state(__state);
845 }
846 }
847 }
848 return __ret;
849 }
851 // _GLIBCXX_RESOLVE_LIB_DEFECTS
852 // 171. Strange seekpos() semantics due to joint position
853 // According to the resolution of DR 171, seekpos should ignore the last
854 // argument (of type openmode).
855 template<typename _CharT, typename _Traits>
856 typename basic_filebuf<_CharT, _Traits>::pos_type
857 basic_filebuf<_CharT, _Traits>::
858 seekpos(pos_type __pos, ios_base::openmode)
859 {
860 pos_type __ret = pos_type(off_type(-1));
861 if (this->is_open())
862 {
863 // Ditch any pback buffers to avoid confusion.
864 _M_destroy_pback();
865 __ret = _M_seek(off_type(__pos), ios_base::beg, __pos.state());
866 }
867 return __ret;
868 }
870 template<typename _CharT, typename _Traits>
871 typename basic_filebuf<_CharT, _Traits>::pos_type
872 basic_filebuf<_CharT, _Traits>::
873 _M_seek(off_type __off, ios_base::seekdir __way, __state_type __state)
874 {
875 pos_type __ret = pos_type(off_type(-1));
876 if (_M_terminate_output())
877 {
878 off_type __file_off = _M_file.seekoff(__off, __way);
879 if (__file_off != off_type(-1))
880 {
881 _M_reading = false;
882 _M_writing = false;
883 _M_ext_next = _M_ext_end = _M_ext_buf;
884 _M_set_buffer(-1);
885 _M_state_cur = __state;
886 __ret = __file_off;
887 __ret.state(_M_state_cur);
888 }
889 }
890 return __ret;
891 }
893 // Returns the distance from the end of the ext buffer to the point
894 // corresponding to gptr(). This is a negative value. Updates __state
895 // from eback() correspondence to gptr().
896 template<typename _CharT, typename _Traits>
897 int basic_filebuf<_CharT, _Traits>::
898 _M_get_ext_pos(__state_type& __state)
899 {
900 if (_M_codecvt->always_noconv())
901 return this->gptr() - this->egptr();
902 else
903 {
904 // Calculate offset from _M_ext_buf that corresponds to
905 // gptr(). Precondition: __state == _M_state_last, which
906 // corresponds to eback().
907 const int __gptr_off =
908 _M_codecvt->length(__state, _M_ext_buf, _M_ext_next,
909 this->gptr() - this->eback());
910 return _M_ext_buf + __gptr_off - _M_ext_end;
911 }
912 }
914 template<typename _CharT, typename _Traits>
915 bool
916 basic_filebuf<_CharT, _Traits>::
917 _M_terminate_output()
918 {
919 // Part one: update the output sequence.
920 bool __testvalid = true;
921 if (this->pbase() < this->pptr())
922 {
923 const int_type __tmp = this->overflow();
924 if (traits_type::eq_int_type(__tmp, traits_type::eof()))
925 __testvalid = false;
926 }
928 // Part two: output unshift sequence.
929 if (_M_writing && !__check_facet(_M_codecvt).always_noconv()
930 && __testvalid)
931 {
932 // Note: this value is arbitrary, since there is no way to
933 // get the length of the unshift sequence from codecvt,
934 // without calling unshift.
935 const size_t __blen = 128;
936 char __buf[__blen];
937 codecvt_base::result __r;
938 streamsize __ilen = 0;
940 do
941 {
942 char* __next;
943 __r = _M_codecvt->unshift(_M_state_cur, __buf,
944 __buf + __blen, __next);
945 if (__r == codecvt_base::error)
946 __testvalid = false;
947 else if (__r == codecvt_base::ok ||
948 __r == codecvt_base::partial)
949 {
950 __ilen = __next - __buf;
951 if (__ilen > 0)
952 {
953 const streamsize __elen = _M_file.xsputn(__buf, __ilen);
954 if (__elen != __ilen)
955 __testvalid = false;
956 }
957 }
958 }
959 while (__r == codecvt_base::partial && __ilen > 0 && __testvalid);
961 if (__testvalid)
962 {
963 // This second call to overflow() is required by the standard,
964 // but it's not clear why it's needed, since the output buffer
965 // should be empty by this point (it should have been emptied
966 // in the first call to overflow()).
967 const int_type __tmp = this->overflow();
968 if (traits_type::eq_int_type(__tmp, traits_type::eof()))
969 __testvalid = false;
970 }
971 }
972 return __testvalid;
973 }
975 template<typename _CharT, typename _Traits>
976 int
977 basic_filebuf<_CharT, _Traits>::
978 sync()
979 {
980 // Make sure that the internal buffer resyncs its idea of
981 // the file position with the external file.
982 int __ret = 0;
983 if (this->pbase() < this->pptr())
984 {
985 const int_type __tmp = this->overflow();
986 if (traits_type::eq_int_type(__tmp, traits_type::eof()))
987 __ret = -1;
988 }
989 return __ret;
990 }
992 template<typename _CharT, typename _Traits>
993 void
994 basic_filebuf<_CharT, _Traits>::
995 imbue(const locale& __loc)
996 {
997 bool __testvalid = true;
999 const __codecvt_type* _M_codecvt_tmp = 0;
1000 if (__builtin_expect(has_facet<__codecvt_type>(__loc), true))
1001 _M_codecvt_tmp = &use_facet<__codecvt_type>(__loc);
1003 if (this->is_open())
1004 {
1005 // encoding() == -1 is ok only at the beginning.
1006 if ((_M_reading || _M_writing)
1007 && __check_facet(_M_codecvt).encoding() == -1)
1008 __testvalid = false;
1009 else
1010 {
1011 if (_M_reading)
1012 {
1013 if (__check_facet(_M_codecvt).always_noconv())
1014 {
1015 if (_M_codecvt_tmp
1016 && !__check_facet(_M_codecvt_tmp).always_noconv())
1017 __testvalid = this->seekoff(0, ios_base::cur, _M_mode)
1018 != pos_type(off_type(-1));
1019 }
1020 else
1021 {
1022 // External position corresponding to gptr().
1023 _M_ext_next = _M_ext_buf
1024 + _M_codecvt->length(_M_state_last, _M_ext_buf,
1025 _M_ext_next,
1026 this->gptr() - this->eback());
1027 const streamsize __remainder = _M_ext_end - _M_ext_next;
1028 if (__remainder)
1029 __builtin_memmove(_M_ext_buf, _M_ext_next, __remainder);
1031 _M_ext_next = _M_ext_buf;
1032 _M_ext_end = _M_ext_buf + __remainder;
1033 _M_set_buffer(-1);
1034 _M_state_last = _M_state_cur = _M_state_beg;
1035 }
1036 }
1037 else if (_M_writing && (__testvalid = _M_terminate_output()))
1038 _M_set_buffer(-1);
1039 }
1040 }
1042 if (__testvalid)
1043 _M_codecvt = _M_codecvt_tmp;
1044 else
1045 _M_codecvt = 0;
1046 }
1048 // Inhibit implicit instantiations for required instantiations,
1049 // which are defined via explicit instantiations elsewhere.
1050 #if _GLIBCXX_EXTERN_TEMPLATE
1051 extern template class basic_filebuf<char>;
1052 extern template class basic_ifstream<char>;
1053 extern template class basic_ofstream<char>;
1054 extern template class basic_fstream<char>;
1056 #ifdef _GLIBCXX_USE_WCHAR_T
1057 extern template class basic_filebuf<wchar_t>;
1058 extern template class basic_ifstream<wchar_t>;
1059 extern template class basic_ofstream<wchar_t>;
1060 extern template class basic_fstream<wchar_t>;
1061 #endif
1062 #endif
1064 _GLIBCXX_END_NAMESPACE_VERSION
1065 } // namespace std
1067 #endif