libstdc++
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00001 // File based streams -*- C++ -*- 00002 00003 // Copyright (C) 1997-2013 Free Software Foundation, Inc. 00004 // 00005 // This file is part of the GNU ISO C++ Library. This library is free 00006 // software; you can redistribute it and/or modify it under the 00007 // terms of the GNU General Public License as published by the 00008 // Free Software Foundation; either version 3, or (at your option) 00009 // any later version. 00010 00011 // This library is distributed in the hope that it will be useful, 00012 // but WITHOUT ANY WARRANTY; without even the implied warranty of 00013 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00014 // GNU General Public License for more details. 00015 00016 // Under Section 7 of GPL version 3, you are granted additional 00017 // permissions described in the GCC Runtime Library Exception, version 00018 // 3.1, as published by the Free Software Foundation. 00019 00020 // You should have received a copy of the GNU General Public License and 00021 // a copy of the GCC Runtime Library Exception along with this program; 00022 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 00023 // <http://www.gnu.org/licenses/>. 00024 00025 /** @file bits/fstream.tcc 00026 * This is an internal header file, included by other library headers. 00027 * Do not attempt to use it directly. @headername{fstream} 00028 */ 00029 00030 // 00031 // ISO C++ 14882: 27.8 File-based streams 00032 // 00033 00034 #ifndef _FSTREAM_TCC 00035 #define _FSTREAM_TCC 1 00036 00037 #pragma GCC system_header 00038 00039 #include <bits/cxxabi_forced.h> 00040 00041 namespace std _GLIBCXX_VISIBILITY(default) 00042 { 00043 _GLIBCXX_BEGIN_NAMESPACE_VERSION 00044 00045 template<typename _CharT, typename _Traits> 00046 void 00047 basic_filebuf<_CharT, _Traits>:: 00048 _M_allocate_internal_buffer() 00049 { 00050 // Allocate internal buffer only if one doesn't already exist 00051 // (either allocated or provided by the user via setbuf). 00052 if (!_M_buf_allocated && !_M_buf) 00053 { 00054 _M_buf = new char_type[_M_buf_size]; 00055 _M_buf_allocated = true; 00056 } 00057 } 00058 00059 template<typename _CharT, typename _Traits> 00060 void 00061 basic_filebuf<_CharT, _Traits>:: 00062 _M_destroy_internal_buffer() throw() 00063 { 00064 if (_M_buf_allocated) 00065 { 00066 delete [] _M_buf; 00067 _M_buf = 0; 00068 _M_buf_allocated = false; 00069 } 00070 delete [] _M_ext_buf; 00071 _M_ext_buf = 0; 00072 _M_ext_buf_size = 0; 00073 _M_ext_next = 0; 00074 _M_ext_end = 0; 00075 } 00076 00077 template<typename _CharT, typename _Traits> 00078 basic_filebuf<_CharT, _Traits>:: 00079 basic_filebuf() : __streambuf_type(), _M_lock(), _M_file(&_M_lock), 00080 _M_mode(ios_base::openmode(0)), _M_state_beg(), _M_state_cur(), 00081 _M_state_last(), _M_buf(0), _M_buf_size(BUFSIZ), 00082 _M_buf_allocated(false), _M_reading(false), _M_writing(false), _M_pback(), 00083 _M_pback_cur_save(0), _M_pback_end_save(0), _M_pback_init(false), 00084 _M_codecvt(0), _M_ext_buf(0), _M_ext_buf_size(0), _M_ext_next(0), 00085 _M_ext_end(0) 00086 { 00087 if (has_facet<__codecvt_type>(this->_M_buf_locale)) 00088 _M_codecvt = &use_facet<__codecvt_type>(this->_M_buf_locale); 00089 } 00090 00091 template<typename _CharT, typename _Traits> 00092 typename basic_filebuf<_CharT, _Traits>::__filebuf_type* 00093 basic_filebuf<_CharT, _Traits>:: 00094 open(const char* __s, ios_base::openmode __mode) 00095 { 00096 __filebuf_type *__ret = 0; 00097 if (!this->is_open()) 00098 { 00099 _M_file.open(__s, __mode); 00100 if (this->is_open()) 00101 { 00102 _M_allocate_internal_buffer(); 00103 _M_mode = __mode; 00104 00105 // Setup initial buffer to 'uncommitted' mode. 00106 _M_reading = false; 00107 _M_writing = false; 00108 _M_set_buffer(-1); 00109 00110 // Reset to initial state. 00111 _M_state_last = _M_state_cur = _M_state_beg; 00112 00113 // 27.8.1.3,4 00114 if ((__mode & ios_base::ate) 00115 && this->seekoff(0, ios_base::end, __mode) 00116 == pos_type(off_type(-1))) 00117 this->close(); 00118 else 00119 __ret = this; 00120 } 00121 } 00122 return __ret; 00123 } 00124 00125 template<typename _CharT, typename _Traits> 00126 typename basic_filebuf<_CharT, _Traits>::__filebuf_type* 00127 basic_filebuf<_CharT, _Traits>:: 00128 close() 00129 { 00130 if (!this->is_open()) 00131 return 0; 00132 00133 bool __testfail = false; 00134 { 00135 // NB: Do this here so that re-opened filebufs will be cool... 00136 struct __close_sentry 00137 { 00138 basic_filebuf *__fb; 00139 __close_sentry (basic_filebuf *__fbi): __fb(__fbi) { } 00140 ~__close_sentry () 00141 { 00142 __fb->_M_mode = ios_base::openmode(0); 00143 __fb->_M_pback_init = false; 00144 __fb->_M_destroy_internal_buffer(); 00145 __fb->_M_reading = false; 00146 __fb->_M_writing = false; 00147 __fb->_M_set_buffer(-1); 00148 __fb->_M_state_last = __fb->_M_state_cur = __fb->_M_state_beg; 00149 } 00150 } __cs (this); 00151 00152 __try 00153 { 00154 if (!_M_terminate_output()) 00155 __testfail = true; 00156 } 00157 __catch(__cxxabiv1::__forced_unwind&) 00158 { 00159 _M_file.close(); 00160 __throw_exception_again; 00161 } 00162 __catch(...) 00163 { __testfail = true; } 00164 } 00165 00166 if (!_M_file.close()) 00167 __testfail = true; 00168 00169 if (__testfail) 00170 return 0; 00171 else 00172 return this; 00173 } 00174 00175 template<typename _CharT, typename _Traits> 00176 streamsize 00177 basic_filebuf<_CharT, _Traits>:: 00178 showmanyc() 00179 { 00180 streamsize __ret = -1; 00181 const bool __testin = _M_mode & ios_base::in; 00182 if (__testin && this->is_open()) 00183 { 00184 // For a stateful encoding (-1) the pending sequence might be just 00185 // shift and unshift prefixes with no actual character. 00186 __ret = this->egptr() - this->gptr(); 00187 00188 #if _GLIBCXX_HAVE_DOS_BASED_FILESYSTEM 00189 // About this workaround, see libstdc++/20806. 00190 const bool __testbinary = _M_mode & ios_base::binary; 00191 if (__check_facet(_M_codecvt).encoding() >= 0 00192 && __testbinary) 00193 #else 00194 if (__check_facet(_M_codecvt).encoding() >= 0) 00195 #endif 00196 __ret += _M_file.showmanyc() / _M_codecvt->max_length(); 00197 } 00198 return __ret; 00199 } 00200 00201 template<typename _CharT, typename _Traits> 00202 typename basic_filebuf<_CharT, _Traits>::int_type 00203 basic_filebuf<_CharT, _Traits>:: 00204 underflow() 00205 { 00206 int_type __ret = traits_type::eof(); 00207 const bool __testin = _M_mode & ios_base::in; 00208 if (__testin) 00209 { 00210 if (_M_writing) 00211 { 00212 if (overflow() == traits_type::eof()) 00213 return __ret; 00214 _M_set_buffer(-1); 00215 _M_writing = false; 00216 } 00217 // Check for pback madness, and if so switch back to the 00218 // normal buffers and jet outta here before expensive 00219 // fileops happen... 00220 _M_destroy_pback(); 00221 00222 if (this->gptr() < this->egptr()) 00223 return traits_type::to_int_type(*this->gptr()); 00224 00225 // Get and convert input sequence. 00226 const size_t __buflen = _M_buf_size > 1 ? _M_buf_size - 1 : 1; 00227 00228 // Will be set to true if ::read() returns 0 indicating EOF. 00229 bool __got_eof = false; 00230 // Number of internal characters produced. 00231 streamsize __ilen = 0; 00232 codecvt_base::result __r = codecvt_base::ok; 00233 if (__check_facet(_M_codecvt).always_noconv()) 00234 { 00235 __ilen = _M_file.xsgetn(reinterpret_cast<char*>(this->eback()), 00236 __buflen); 00237 if (__ilen == 0) 00238 __got_eof = true; 00239 } 00240 else 00241 { 00242 // Worst-case number of external bytes. 00243 // XXX Not done encoding() == -1. 00244 const int __enc = _M_codecvt->encoding(); 00245 streamsize __blen; // Minimum buffer size. 00246 streamsize __rlen; // Number of chars to read. 00247 if (__enc > 0) 00248 __blen = __rlen = __buflen * __enc; 00249 else 00250 { 00251 __blen = __buflen + _M_codecvt->max_length() - 1; 00252 __rlen = __buflen; 00253 } 00254 const streamsize __remainder = _M_ext_end - _M_ext_next; 00255 __rlen = __rlen > __remainder ? __rlen - __remainder : 0; 00256 00257 // An imbue in 'read' mode implies first converting the external 00258 // chars already present. 00259 if (_M_reading && this->egptr() == this->eback() && __remainder) 00260 __rlen = 0; 00261 00262 // Allocate buffer if necessary and move unconverted 00263 // bytes to front. 00264 if (_M_ext_buf_size < __blen) 00265 { 00266 char* __buf = new char[__blen]; 00267 if (__remainder) 00268 __builtin_memcpy(__buf, _M_ext_next, __remainder); 00269 00270 delete [] _M_ext_buf; 00271 _M_ext_buf = __buf; 00272 _M_ext_buf_size = __blen; 00273 } 00274 else if (__remainder) 00275 __builtin_memmove(_M_ext_buf, _M_ext_next, __remainder); 00276 00277 _M_ext_next = _M_ext_buf; 00278 _M_ext_end = _M_ext_buf + __remainder; 00279 _M_state_last = _M_state_cur; 00280 00281 do 00282 { 00283 if (__rlen > 0) 00284 { 00285 // Sanity check! 00286 // This may fail if the return value of 00287 // codecvt::max_length() is bogus. 00288 if (_M_ext_end - _M_ext_buf + __rlen > _M_ext_buf_size) 00289 { 00290 __throw_ios_failure(__N("basic_filebuf::underflow " 00291 "codecvt::max_length() " 00292 "is not valid")); 00293 } 00294 streamsize __elen = _M_file.xsgetn(_M_ext_end, __rlen); 00295 if (__elen == 0) 00296 __got_eof = true; 00297 else if (__elen == -1) 00298 break; 00299 _M_ext_end += __elen; 00300 } 00301 00302 char_type* __iend = this->eback(); 00303 if (_M_ext_next < _M_ext_end) 00304 __r = _M_codecvt->in(_M_state_cur, _M_ext_next, 00305 _M_ext_end, _M_ext_next, 00306 this->eback(), 00307 this->eback() + __buflen, __iend); 00308 if (__r == codecvt_base::noconv) 00309 { 00310 size_t __avail = _M_ext_end - _M_ext_buf; 00311 __ilen = std::min(__avail, __buflen); 00312 traits_type::copy(this->eback(), 00313 reinterpret_cast<char_type*> 00314 (_M_ext_buf), __ilen); 00315 _M_ext_next = _M_ext_buf + __ilen; 00316 } 00317 else 00318 __ilen = __iend - this->eback(); 00319 00320 // _M_codecvt->in may return error while __ilen > 0: this is 00321 // ok, and actually occurs in case of mixed encodings (e.g., 00322 // XML files). 00323 if (__r == codecvt_base::error) 00324 break; 00325 00326 __rlen = 1; 00327 } 00328 while (__ilen == 0 && !__got_eof); 00329 } 00330 00331 if (__ilen > 0) 00332 { 00333 _M_set_buffer(__ilen); 00334 _M_reading = true; 00335 __ret = traits_type::to_int_type(*this->gptr()); 00336 } 00337 else if (__got_eof) 00338 { 00339 // If the actual end of file is reached, set 'uncommitted' 00340 // mode, thus allowing an immediate write without an 00341 // intervening seek. 00342 _M_set_buffer(-1); 00343 _M_reading = false; 00344 // However, reaching it while looping on partial means that 00345 // the file has got an incomplete character. 00346 if (__r == codecvt_base::partial) 00347 __throw_ios_failure(__N("basic_filebuf::underflow " 00348 "incomplete character in file")); 00349 } 00350 else if (__r == codecvt_base::error) 00351 __throw_ios_failure(__N("basic_filebuf::underflow " 00352 "invalid byte sequence in file")); 00353 else 00354 __throw_ios_failure(__N("basic_filebuf::underflow " 00355 "error reading the file")); 00356 } 00357 return __ret; 00358 } 00359 00360 template<typename _CharT, typename _Traits> 00361 typename basic_filebuf<_CharT, _Traits>::int_type 00362 basic_filebuf<_CharT, _Traits>:: 00363 pbackfail(int_type __i) 00364 { 00365 int_type __ret = traits_type::eof(); 00366 const bool __testin = _M_mode & ios_base::in; 00367 if (__testin) 00368 { 00369 if (_M_writing) 00370 { 00371 if (overflow() == traits_type::eof()) 00372 return __ret; 00373 _M_set_buffer(-1); 00374 _M_writing = false; 00375 } 00376 // Remember whether the pback buffer is active, otherwise below 00377 // we may try to store in it a second char (libstdc++/9761). 00378 const bool __testpb = _M_pback_init; 00379 const bool __testeof = traits_type::eq_int_type(__i, __ret); 00380 int_type __tmp; 00381 if (this->eback() < this->gptr()) 00382 { 00383 this->gbump(-1); 00384 __tmp = traits_type::to_int_type(*this->gptr()); 00385 } 00386 else if (this->seekoff(-1, ios_base::cur) != pos_type(off_type(-1))) 00387 { 00388 __tmp = this->underflow(); 00389 if (traits_type::eq_int_type(__tmp, __ret)) 00390 return __ret; 00391 } 00392 else 00393 { 00394 // At the beginning of the buffer, need to make a 00395 // putback position available. But the seek may fail 00396 // (f.i., at the beginning of a file, see 00397 // libstdc++/9439) and in that case we return 00398 // traits_type::eof(). 00399 return __ret; 00400 } 00401 00402 // Try to put back __i into input sequence in one of three ways. 00403 // Order these tests done in is unspecified by the standard. 00404 if (!__testeof && traits_type::eq_int_type(__i, __tmp)) 00405 __ret = __i; 00406 else if (__testeof) 00407 __ret = traits_type::not_eof(__i); 00408 else if (!__testpb) 00409 { 00410 _M_create_pback(); 00411 _M_reading = true; 00412 *this->gptr() = traits_type::to_char_type(__i); 00413 __ret = __i; 00414 } 00415 } 00416 return __ret; 00417 } 00418 00419 template<typename _CharT, typename _Traits> 00420 typename basic_filebuf<_CharT, _Traits>::int_type 00421 basic_filebuf<_CharT, _Traits>:: 00422 overflow(int_type __c) 00423 { 00424 int_type __ret = traits_type::eof(); 00425 const bool __testeof = traits_type::eq_int_type(__c, __ret); 00426 const bool __testout = _M_mode & ios_base::out; 00427 if (__testout) 00428 { 00429 if (_M_reading) 00430 { 00431 _M_destroy_pback(); 00432 const int __gptr_off = _M_get_ext_pos(_M_state_last); 00433 if (_M_seek(__gptr_off, ios_base::cur, _M_state_last) 00434 == pos_type(off_type(-1))) 00435 return __ret; 00436 } 00437 if (this->pbase() < this->pptr()) 00438 { 00439 // If appropriate, append the overflow char. 00440 if (!__testeof) 00441 { 00442 *this->pptr() = traits_type::to_char_type(__c); 00443 this->pbump(1); 00444 } 00445 00446 // Convert pending sequence to external representation, 00447 // and output. 00448 if (_M_convert_to_external(this->pbase(), 00449 this->pptr() - this->pbase())) 00450 { 00451 _M_set_buffer(0); 00452 __ret = traits_type::not_eof(__c); 00453 } 00454 } 00455 else if (_M_buf_size > 1) 00456 { 00457 // Overflow in 'uncommitted' mode: set _M_writing, set 00458 // the buffer to the initial 'write' mode, and put __c 00459 // into the buffer. 00460 _M_set_buffer(0); 00461 _M_writing = true; 00462 if (!__testeof) 00463 { 00464 *this->pptr() = traits_type::to_char_type(__c); 00465 this->pbump(1); 00466 } 00467 __ret = traits_type::not_eof(__c); 00468 } 00469 else 00470 { 00471 // Unbuffered. 00472 char_type __conv = traits_type::to_char_type(__c); 00473 if (__testeof || _M_convert_to_external(&__conv, 1)) 00474 { 00475 _M_writing = true; 00476 __ret = traits_type::not_eof(__c); 00477 } 00478 } 00479 } 00480 return __ret; 00481 } 00482 00483 template<typename _CharT, typename _Traits> 00484 bool 00485 basic_filebuf<_CharT, _Traits>:: 00486 _M_convert_to_external(_CharT* __ibuf, streamsize __ilen) 00487 { 00488 // Sizes of external and pending output. 00489 streamsize __elen; 00490 streamsize __plen; 00491 if (__check_facet(_M_codecvt).always_noconv()) 00492 { 00493 __elen = _M_file.xsputn(reinterpret_cast<char*>(__ibuf), __ilen); 00494 __plen = __ilen; 00495 } 00496 else 00497 { 00498 // Worst-case number of external bytes needed. 00499 // XXX Not done encoding() == -1. 00500 streamsize __blen = __ilen * _M_codecvt->max_length(); 00501 char* __buf = static_cast<char*>(__builtin_alloca(__blen)); 00502 00503 char* __bend; 00504 const char_type* __iend; 00505 codecvt_base::result __r; 00506 __r = _M_codecvt->out(_M_state_cur, __ibuf, __ibuf + __ilen, 00507 __iend, __buf, __buf + __blen, __bend); 00508 00509 if (__r == codecvt_base::ok || __r == codecvt_base::partial) 00510 __blen = __bend - __buf; 00511 else if (__r == codecvt_base::noconv) 00512 { 00513 // Same as the always_noconv case above. 00514 __buf = reinterpret_cast<char*>(__ibuf); 00515 __blen = __ilen; 00516 } 00517 else 00518 __throw_ios_failure(__N("basic_filebuf::_M_convert_to_external " 00519 "conversion error")); 00520 00521 __elen = _M_file.xsputn(__buf, __blen); 00522 __plen = __blen; 00523 00524 // Try once more for partial conversions. 00525 if (__r == codecvt_base::partial && __elen == __plen) 00526 { 00527 const char_type* __iresume = __iend; 00528 streamsize __rlen = this->pptr() - __iend; 00529 __r = _M_codecvt->out(_M_state_cur, __iresume, 00530 __iresume + __rlen, __iend, __buf, 00531 __buf + __blen, __bend); 00532 if (__r != codecvt_base::error) 00533 { 00534 __rlen = __bend - __buf; 00535 __elen = _M_file.xsputn(__buf, __rlen); 00536 __plen = __rlen; 00537 } 00538 else 00539 __throw_ios_failure(__N("basic_filebuf::_M_convert_to_external " 00540 "conversion error")); 00541 } 00542 } 00543 return __elen == __plen; 00544 } 00545 00546 template<typename _CharT, typename _Traits> 00547 streamsize 00548 basic_filebuf<_CharT, _Traits>:: 00549 xsgetn(_CharT* __s, streamsize __n) 00550 { 00551 // Clear out pback buffer before going on to the real deal... 00552 streamsize __ret = 0; 00553 if (_M_pback_init) 00554 { 00555 if (__n > 0 && this->gptr() == this->eback()) 00556 { 00557 *__s++ = *this->gptr(); // emulate non-underflowing sbumpc 00558 this->gbump(1); 00559 __ret = 1; 00560 --__n; 00561 } 00562 _M_destroy_pback(); 00563 } 00564 else if (_M_writing) 00565 { 00566 if (overflow() == traits_type::eof()) 00567 return __ret; 00568 _M_set_buffer(-1); 00569 _M_writing = false; 00570 } 00571 00572 // Optimization in the always_noconv() case, to be generalized in the 00573 // future: when __n > __buflen we read directly instead of using the 00574 // buffer repeatedly. 00575 const bool __testin = _M_mode & ios_base::in; 00576 const streamsize __buflen = _M_buf_size > 1 ? _M_buf_size - 1 : 1; 00577 00578 if (__n > __buflen && __check_facet(_M_codecvt).always_noconv() 00579 && __testin) 00580 { 00581 // First, copy the chars already present in the buffer. 00582 const streamsize __avail = this->egptr() - this->gptr(); 00583 if (__avail != 0) 00584 { 00585 traits_type::copy(__s, this->gptr(), __avail); 00586 __s += __avail; 00587 this->setg(this->eback(), this->gptr() + __avail, 00588 this->egptr()); 00589 __ret += __avail; 00590 __n -= __avail; 00591 } 00592 00593 // Need to loop in case of short reads (relatively common 00594 // with pipes). 00595 streamsize __len; 00596 for (;;) 00597 { 00598 __len = _M_file.xsgetn(reinterpret_cast<char*>(__s), 00599 __n); 00600 if (__len == -1) 00601 __throw_ios_failure(__N("basic_filebuf::xsgetn " 00602 "error reading the file")); 00603 if (__len == 0) 00604 break; 00605 00606 __n -= __len; 00607 __ret += __len; 00608 if (__n == 0) 00609 break; 00610 00611 __s += __len; 00612 } 00613 00614 if (__n == 0) 00615 { 00616 _M_set_buffer(0); 00617 _M_reading = true; 00618 } 00619 else if (__len == 0) 00620 { 00621 // If end of file is reached, set 'uncommitted' 00622 // mode, thus allowing an immediate write without 00623 // an intervening seek. 00624 _M_set_buffer(-1); 00625 _M_reading = false; 00626 } 00627 } 00628 else 00629 __ret += __streambuf_type::xsgetn(__s, __n); 00630 00631 return __ret; 00632 } 00633 00634 template<typename _CharT, typename _Traits> 00635 streamsize 00636 basic_filebuf<_CharT, _Traits>:: 00637 xsputn(const _CharT* __s, streamsize __n) 00638 { 00639 streamsize __ret = 0; 00640 // Optimization in the always_noconv() case, to be generalized in the 00641 // future: when __n is sufficiently large we write directly instead of 00642 // using the buffer. 00643 const bool __testout = _M_mode & ios_base::out; 00644 if (__check_facet(_M_codecvt).always_noconv() 00645 && __testout && !_M_reading) 00646 { 00647 // Measurement would reveal the best choice. 00648 const streamsize __chunk = 1ul << 10; 00649 streamsize __bufavail = this->epptr() - this->pptr(); 00650 00651 // Don't mistake 'uncommitted' mode buffered with unbuffered. 00652 if (!_M_writing && _M_buf_size > 1) 00653 __bufavail = _M_buf_size - 1; 00654 00655 const streamsize __limit = std::min(__chunk, __bufavail); 00656 if (__n >= __limit) 00657 { 00658 const streamsize __buffill = this->pptr() - this->pbase(); 00659 const char* __buf = reinterpret_cast<const char*>(this->pbase()); 00660 __ret = _M_file.xsputn_2(__buf, __buffill, 00661 reinterpret_cast<const char*>(__s), 00662 __n); 00663 if (__ret == __buffill + __n) 00664 { 00665 _M_set_buffer(0); 00666 _M_writing = true; 00667 } 00668 if (__ret > __buffill) 00669 __ret -= __buffill; 00670 else 00671 __ret = 0; 00672 } 00673 else 00674 __ret = __streambuf_type::xsputn(__s, __n); 00675 } 00676 else 00677 __ret = __streambuf_type::xsputn(__s, __n); 00678 return __ret; 00679 } 00680 00681 template<typename _CharT, typename _Traits> 00682 typename basic_filebuf<_CharT, _Traits>::__streambuf_type* 00683 basic_filebuf<_CharT, _Traits>:: 00684 setbuf(char_type* __s, streamsize __n) 00685 { 00686 if (!this->is_open()) 00687 { 00688 if (__s == 0 && __n == 0) 00689 _M_buf_size = 1; 00690 else if (__s && __n > 0) 00691 { 00692 // This is implementation-defined behavior, and assumes that 00693 // an external char_type array of length __n exists and has 00694 // been pre-allocated. If this is not the case, things will 00695 // quickly blow up. When __n > 1, __n - 1 positions will be 00696 // used for the get area, __n - 1 for the put area and 1 00697 // position to host the overflow char of a full put area. 00698 // When __n == 1, 1 position will be used for the get area 00699 // and 0 for the put area, as in the unbuffered case above. 00700 _M_buf = __s; 00701 _M_buf_size = __n; 00702 } 00703 } 00704 return this; 00705 } 00706 00707 00708 // According to 27.8.1.4 p11 - 13, seekoff should ignore the last 00709 // argument (of type openmode). 00710 template<typename _CharT, typename _Traits> 00711 typename basic_filebuf<_CharT, _Traits>::pos_type 00712 basic_filebuf<_CharT, _Traits>:: 00713 seekoff(off_type __off, ios_base::seekdir __way, ios_base::openmode) 00714 { 00715 int __width = 0; 00716 if (_M_codecvt) 00717 __width = _M_codecvt->encoding(); 00718 if (__width < 0) 00719 __width = 0; 00720 00721 pos_type __ret = pos_type(off_type(-1)); 00722 const bool __testfail = __off != 0 && __width <= 0; 00723 if (this->is_open() && !__testfail) 00724 { 00725 // tellg and tellp queries do not affect any state, unless 00726 // ! always_noconv and the put sequence is not empty. 00727 // In that case, determining the position requires converting the 00728 // put sequence. That doesn't use ext_buf, so requires a flush. 00729 bool __no_movement = __way == ios_base::cur && __off == 0 00730 && (!_M_writing || _M_codecvt->always_noconv()); 00731 00732 // Ditch any pback buffers to avoid confusion. 00733 if (!__no_movement) 00734 _M_destroy_pback(); 00735 00736 // Correct state at destination. Note that this is the correct 00737 // state for the current position during output, because 00738 // codecvt::unshift() returns the state to the initial state. 00739 // This is also the correct state at the end of the file because 00740 // an unshift sequence should have been written at the end. 00741 __state_type __state = _M_state_beg; 00742 off_type __computed_off = __off * __width; 00743 if (_M_reading && __way == ios_base::cur) 00744 { 00745 __state = _M_state_last; 00746 __computed_off += _M_get_ext_pos(__state); 00747 } 00748 if (!__no_movement) 00749 __ret = _M_seek(__computed_off, __way, __state); 00750 else 00751 { 00752 if (_M_writing) 00753 __computed_off = this->pptr() - this->pbase(); 00754 00755 off_type __file_off = _M_file.seekoff(0, ios_base::cur); 00756 if (__file_off != off_type(-1)) 00757 { 00758 __ret = __file_off + __computed_off; 00759 __ret.state(__state); 00760 } 00761 } 00762 } 00763 return __ret; 00764 } 00765 00766 // _GLIBCXX_RESOLVE_LIB_DEFECTS 00767 // 171. Strange seekpos() semantics due to joint position 00768 // According to the resolution of DR 171, seekpos should ignore the last 00769 // argument (of type openmode). 00770 template<typename _CharT, typename _Traits> 00771 typename basic_filebuf<_CharT, _Traits>::pos_type 00772 basic_filebuf<_CharT, _Traits>:: 00773 seekpos(pos_type __pos, ios_base::openmode) 00774 { 00775 pos_type __ret = pos_type(off_type(-1)); 00776 if (this->is_open()) 00777 { 00778 // Ditch any pback buffers to avoid confusion. 00779 _M_destroy_pback(); 00780 __ret = _M_seek(off_type(__pos), ios_base::beg, __pos.state()); 00781 } 00782 return __ret; 00783 } 00784 00785 template<typename _CharT, typename _Traits> 00786 typename basic_filebuf<_CharT, _Traits>::pos_type 00787 basic_filebuf<_CharT, _Traits>:: 00788 _M_seek(off_type __off, ios_base::seekdir __way, __state_type __state) 00789 { 00790 pos_type __ret = pos_type(off_type(-1)); 00791 if (_M_terminate_output()) 00792 { 00793 off_type __file_off = _M_file.seekoff(__off, __way); 00794 if (__file_off != off_type(-1)) 00795 { 00796 _M_reading = false; 00797 _M_writing = false; 00798 _M_ext_next = _M_ext_end = _M_ext_buf; 00799 _M_set_buffer(-1); 00800 _M_state_cur = __state; 00801 __ret = __file_off; 00802 __ret.state(_M_state_cur); 00803 } 00804 } 00805 return __ret; 00806 } 00807 00808 // Returns the distance from the end of the ext buffer to the point 00809 // corresponding to gptr(). This is a negative value. Updates __state 00810 // from eback() correspondence to gptr(). 00811 template<typename _CharT, typename _Traits> 00812 int basic_filebuf<_CharT, _Traits>:: 00813 _M_get_ext_pos(__state_type& __state) 00814 { 00815 if (_M_codecvt->always_noconv()) 00816 return this->gptr() - this->egptr(); 00817 else 00818 { 00819 // Calculate offset from _M_ext_buf that corresponds to 00820 // gptr(). Precondition: __state == _M_state_last, which 00821 // corresponds to eback(). 00822 const int __gptr_off = 00823 _M_codecvt->length(__state, _M_ext_buf, _M_ext_next, 00824 this->gptr() - this->eback()); 00825 return _M_ext_buf + __gptr_off - _M_ext_end; 00826 } 00827 } 00828 00829 template<typename _CharT, typename _Traits> 00830 bool 00831 basic_filebuf<_CharT, _Traits>:: 00832 _M_terminate_output() 00833 { 00834 // Part one: update the output sequence. 00835 bool __testvalid = true; 00836 if (this->pbase() < this->pptr()) 00837 { 00838 const int_type __tmp = this->overflow(); 00839 if (traits_type::eq_int_type(__tmp, traits_type::eof())) 00840 __testvalid = false; 00841 } 00842 00843 // Part two: output unshift sequence. 00844 if (_M_writing && !__check_facet(_M_codecvt).always_noconv() 00845 && __testvalid) 00846 { 00847 // Note: this value is arbitrary, since there is no way to 00848 // get the length of the unshift sequence from codecvt, 00849 // without calling unshift. 00850 const size_t __blen = 128; 00851 char __buf[__blen]; 00852 codecvt_base::result __r; 00853 streamsize __ilen = 0; 00854 00855 do 00856 { 00857 char* __next; 00858 __r = _M_codecvt->unshift(_M_state_cur, __buf, 00859 __buf + __blen, __next); 00860 if (__r == codecvt_base::error) 00861 __testvalid = false; 00862 else if (__r == codecvt_base::ok || 00863 __r == codecvt_base::partial) 00864 { 00865 __ilen = __next - __buf; 00866 if (__ilen > 0) 00867 { 00868 const streamsize __elen = _M_file.xsputn(__buf, __ilen); 00869 if (__elen != __ilen) 00870 __testvalid = false; 00871 } 00872 } 00873 } 00874 while (__r == codecvt_base::partial && __ilen > 0 && __testvalid); 00875 00876 if (__testvalid) 00877 { 00878 // This second call to overflow() is required by the standard, 00879 // but it's not clear why it's needed, since the output buffer 00880 // should be empty by this point (it should have been emptied 00881 // in the first call to overflow()). 00882 const int_type __tmp = this->overflow(); 00883 if (traits_type::eq_int_type(__tmp, traits_type::eof())) 00884 __testvalid = false; 00885 } 00886 } 00887 return __testvalid; 00888 } 00889 00890 template<typename _CharT, typename _Traits> 00891 int 00892 basic_filebuf<_CharT, _Traits>:: 00893 sync() 00894 { 00895 // Make sure that the internal buffer resyncs its idea of 00896 // the file position with the external file. 00897 int __ret = 0; 00898 if (this->pbase() < this->pptr()) 00899 { 00900 const int_type __tmp = this->overflow(); 00901 if (traits_type::eq_int_type(__tmp, traits_type::eof())) 00902 __ret = -1; 00903 } 00904 return __ret; 00905 } 00906 00907 template<typename _CharT, typename _Traits> 00908 void 00909 basic_filebuf<_CharT, _Traits>:: 00910 imbue(const locale& __loc) 00911 { 00912 bool __testvalid = true; 00913 00914 const __codecvt_type* _M_codecvt_tmp = 0; 00915 if (__builtin_expect(has_facet<__codecvt_type>(__loc), true)) 00916 _M_codecvt_tmp = &use_facet<__codecvt_type>(__loc); 00917 00918 if (this->is_open()) 00919 { 00920 // encoding() == -1 is ok only at the beginning. 00921 if ((_M_reading || _M_writing) 00922 && __check_facet(_M_codecvt).encoding() == -1) 00923 __testvalid = false; 00924 else 00925 { 00926 if (_M_reading) 00927 { 00928 if (__check_facet(_M_codecvt).always_noconv()) 00929 { 00930 if (_M_codecvt_tmp 00931 && !__check_facet(_M_codecvt_tmp).always_noconv()) 00932 __testvalid = this->seekoff(0, ios_base::cur, _M_mode) 00933 != pos_type(off_type(-1)); 00934 } 00935 else 00936 { 00937 // External position corresponding to gptr(). 00938 _M_ext_next = _M_ext_buf 00939 + _M_codecvt->length(_M_state_last, _M_ext_buf, 00940 _M_ext_next, 00941 this->gptr() - this->eback()); 00942 const streamsize __remainder = _M_ext_end - _M_ext_next; 00943 if (__remainder) 00944 __builtin_memmove(_M_ext_buf, _M_ext_next, __remainder); 00945 00946 _M_ext_next = _M_ext_buf; 00947 _M_ext_end = _M_ext_buf + __remainder; 00948 _M_set_buffer(-1); 00949 _M_state_last = _M_state_cur = _M_state_beg; 00950 } 00951 } 00952 else if (_M_writing && (__testvalid = _M_terminate_output())) 00953 _M_set_buffer(-1); 00954 } 00955 } 00956 00957 if (__testvalid) 00958 _M_codecvt = _M_codecvt_tmp; 00959 else 00960 _M_codecvt = 0; 00961 } 00962 00963 // Inhibit implicit instantiations for required instantiations, 00964 // which are defined via explicit instantiations elsewhere. 00965 #if _GLIBCXX_EXTERN_TEMPLATE 00966 extern template class basic_filebuf<char>; 00967 extern template class basic_ifstream<char>; 00968 extern template class basic_ofstream<char>; 00969 extern template class basic_fstream<char>; 00970 00971 #ifdef _GLIBCXX_USE_WCHAR_T 00972 extern template class basic_filebuf<wchar_t>; 00973 extern template class basic_ifstream<wchar_t>; 00974 extern template class basic_ofstream<wchar_t>; 00975 extern template class basic_fstream<wchar_t>; 00976 #endif 00977 #endif 00978 00979 _GLIBCXX_END_NAMESPACE_VERSION 00980 } // namespace std 00981 00982 #endif