fstream.tcc

00001 // File based streams -*- C++ -*-
00002 
00003 // Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002
00004 // Free Software Foundation, Inc.
00005 //
00006 // This file is part of the GNU ISO C++ Library.  This library is free
00007 // software; you can redistribute it and/or modify it under the
00008 // terms of the GNU General Public License as published by the
00009 // Free Software Foundation; either version 2, or (at your option)
00010 // any later version.
00011 
00012 // This library is distributed in the hope that it will be useful,
00013 // but WITHOUT ANY WARRANTY; without even the implied warranty of
00014 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00015 // GNU General Public License for more details.
00016 
00017 // You should have received a copy of the GNU General Public License along
00018 // with this library; see the file COPYING.  If not, write to the Free
00019 // Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
00020 // USA.
00021 
00022 // As a special exception, you may use this file as part of a free software
00023 // library without restriction.  Specifically, if other files instantiate
00024 // templates or use macros or inline functions from this file, or you compile
00025 // this file and link it with other files to produce an executable, this
00026 // file does not by itself cause the resulting executable to be covered by
00027 // the GNU General Public License.  This exception does not however
00028 // invalidate any other reasons why the executable file might be covered by
00029 // the GNU General Public License.
00030 
00031 //
00032 // ISO C++ 14882: 27.8  File-based streams
00033 //
00034 
00035 #ifndef _CPP_BITS_FSTREAM_TCC
00036 #define _CPP_BITS_FSTREAM_TCC 1
00037 
00038 #pragma GCC system_header
00039 
00040 namespace std
00041 {
00042   template<typename _CharT, typename _Traits>
00043     void
00044     basic_filebuf<_CharT, _Traits>::
00045     _M_allocate_internal_buffer()
00046     {
00047       if (!_M_buf && _M_buf_size_opt)
00048     {
00049       _M_buf_size = _M_buf_size_opt;
00050 
00051       // Allocate internal buffer.
00052       try { _M_buf = new char_type[_M_buf_size]; }
00053       catch(...) 
00054         {
00055           delete [] _M_buf;
00056           __throw_exception_again;
00057         }
00058       _M_buf_allocated = true;
00059     }
00060     }
00061 
00062   // Both close and setbuf need to deallocate internal buffers, if it exists.
00063   template<typename _CharT, typename _Traits>
00064     void
00065     basic_filebuf<_CharT, _Traits>::
00066     _M_destroy_internal_buffer()
00067     {
00068       if (_M_buf_allocated)
00069     {
00070       delete [] _M_buf;
00071       _M_buf = NULL;
00072       _M_buf_allocated = false;
00073       this->setg(NULL, NULL, NULL);
00074       this->setp(NULL, NULL);
00075     }
00076     }
00077 
00078   template<typename _CharT, typename _Traits>
00079     basic_filebuf<_CharT, _Traits>::
00080     basic_filebuf() : __streambuf_type(), _M_file(&_M_lock), 
00081     _M_state_cur(__state_type()), _M_state_beg(__state_type()), 
00082     _M_buf_allocated(false), _M_last_overflowed(false)
00083     { _M_buf_unified = true; }
00084 
00085   template<typename _CharT, typename _Traits>
00086     typename basic_filebuf<_CharT, _Traits>::__filebuf_type* 
00087     basic_filebuf<_CharT, _Traits>::
00088     open(const char* __s, ios_base::openmode __mode)
00089     {
00090       __filebuf_type *__ret = NULL;
00091       if (!this->is_open())
00092     {
00093       _M_file.open(__s, __mode);
00094       if (this->is_open())
00095         {
00096           _M_allocate_internal_buffer();
00097           _M_mode = __mode;
00098           
00099           // For time being, set both (in/out) sets  of pointers.
00100           _M_set_indeterminate();
00101           if ((__mode & ios_base::ate)
00102           && this->seekoff(0, ios_base::end, __mode) < 0)
00103         this->close();
00104           __ret = this;
00105         }
00106     }
00107       return __ret;
00108     }
00109 
00110   template<typename _CharT, typename _Traits>
00111     typename basic_filebuf<_CharT, _Traits>::__filebuf_type* 
00112     basic_filebuf<_CharT, _Traits>::
00113     close()
00114     {
00115       __filebuf_type *__ret = NULL;
00116       if (this->is_open())
00117     {
00118       const int_type __eof = traits_type::eof();
00119       bool __testput = _M_out_cur && _M_out_beg < _M_out_end;
00120       if (__testput && _M_really_overflow(__eof) == __eof)
00121         return __ret;
00122 
00123       // NB: Do this here so that re-opened filebufs will be cool...
00124       _M_mode = ios_base::openmode(0);
00125       _M_destroy_internal_buffer();
00126       _M_pback_destroy();
00127       
00128 #if 0
00129       // XXX not done
00130       if (_M_last_overflowed)
00131         {
00132           _M_output_unshift();
00133           _M_really_overflow(__eof);
00134         }
00135 #endif
00136 
00137       if (_M_file.close())
00138         __ret = this;
00139     }
00140 
00141       _M_last_overflowed = false;   
00142       return __ret;
00143     }
00144 
00145   template<typename _CharT, typename _Traits>
00146     streamsize 
00147     basic_filebuf<_CharT, _Traits>::
00148     showmanyc()
00149     {
00150       streamsize __ret = -1;
00151       bool __testin = _M_mode & ios_base::in;
00152 
00153       if (__testin && this->is_open())
00154     {
00155       if (_M_in_cur < _M_in_end)
00156         __ret = _M_in_end - _M_in_cur;
00157       else
00158         __ret = 0;
00159     }
00160       _M_last_overflowed = false;   
00161       return __ret;
00162     }
00163 
00164   template<typename _CharT, typename _Traits>
00165     typename basic_filebuf<_CharT, _Traits>::int_type 
00166     basic_filebuf<_CharT, _Traits>::
00167     _M_underflow_common(bool __bump)
00168     {
00169       int_type __ret = traits_type::eof();
00170       bool __testin = _M_mode & ios_base::in;
00171       bool __testout = _M_mode & ios_base::out;
00172 
00173       if (__testin)
00174     {
00175       // Check for pback madness, and if so swich back to the
00176       // normal buffers and jet outta here before expensive
00177       // fileops happen...
00178       if (_M_pback_init)
00179         {
00180           _M_pback_destroy();
00181           if (_M_in_cur < _M_in_end)
00182         return traits_type::to_int_type(*_M_in_cur);
00183         }
00184 
00185       // Check for unbuffered stream.
00186       if (_M_buf_size == 1)
00187         {
00188           int_type __c = _M_file.sys_getc();
00189           if (__c != __ret)
00190         {
00191           __ret = __c;
00192           *_M_in_cur = traits_type::to_char_type(__c);
00193           _M_set_determinate(1);
00194           if (__testout)
00195             _M_out_cur = _M_in_cur;
00196         }
00197           return __ret;
00198         }
00199 
00200       // Sync internal and external buffers.
00201       // NB: __testget -> __testput as _M_buf_unified here.
00202       bool __testget = _M_in_cur && _M_in_beg < _M_in_cur;
00203       bool __testinit = _M_is_indeterminate();
00204       if (__testget)
00205         {
00206           if (__testout)
00207         _M_really_overflow();
00208           else if (_M_in_cur != _M_filepos)
00209         _M_file.seekoff(_M_in_cur - _M_filepos,
00210                 ios_base::cur, ios_base::in);
00211         }
00212 
00213       if (__testinit || __testget)
00214         {
00215           const locale __loc = this->getloc();
00216           const __codecvt_type& __cvt = use_facet<__codecvt_type>(__loc); 
00217 
00218           streamsize __elen = 0;
00219           streamsize __ilen = 0;
00220           if (__cvt.always_noconv())
00221         {
00222           __elen = _M_file.xsgetn(reinterpret_cast<char*>(_M_in_beg), 
00223                       _M_buf_size);
00224           __ilen = __elen;
00225         }
00226           else
00227         {
00228           char* __buf = static_cast<char*>(__builtin_alloca(_M_buf_size));
00229           __elen = _M_file.xsgetn(__buf, _M_buf_size);
00230 
00231           const char* __eend;
00232           char_type* __iend;
00233           __res_type __r = __cvt.in(_M_state_cur, __buf, 
00234                         __buf + __elen, __eend, _M_in_beg, 
00235                         _M_in_beg + _M_buf_size, __iend);
00236           if (__r == codecvt_base::ok)
00237             __ilen = __iend - _M_in_beg;
00238           else 
00239             {
00240               // Unwind.
00241               __ilen = 0;
00242               _M_file.seekoff(-__elen, ios_base::cur, ios_base::in);
00243             }
00244         }
00245 
00246           if (0 < __ilen)
00247         {
00248           _M_set_determinate(__ilen);
00249           if (__testout)
00250             _M_out_cur = _M_in_cur;
00251           __ret = traits_type::to_int_type(*_M_in_cur);
00252           if (__bump)
00253             _M_in_cur_move(1);
00254         }      
00255         }
00256     }
00257       _M_last_overflowed = false;   
00258       return __ret;
00259     }
00260   
00261   template<typename _CharT, typename _Traits>
00262     typename basic_filebuf<_CharT, _Traits>::int_type 
00263     basic_filebuf<_CharT, _Traits>::
00264     pbackfail(int_type __i)
00265     {
00266       int_type __ret = traits_type::eof();
00267       bool __testin = _M_mode & ios_base::in;
00268 
00269       if (__testin)
00270     {
00271       bool __testpb = _M_in_beg < _M_in_cur;
00272       char_type __c = traits_type::to_char_type(__i);
00273       bool __testeof = traits_type::eq_int_type(__i, __ret);
00274 
00275       if (__testpb)
00276         {
00277           bool __testout = _M_mode & ios_base::out;
00278           bool __testeq = traits_type::eq(__c, this->gptr()[-1]);
00279 
00280           // Try to put back __c into input sequence in one of three ways.
00281           // Order these tests done in is unspecified by the standard.
00282           if (!__testeof && __testeq)
00283         {
00284           --_M_in_cur;
00285           if (__testout)
00286             --_M_out_cur;
00287           __ret = __i;
00288         }
00289           else if (__testeof)
00290         {
00291           --_M_in_cur;
00292           if (__testout)
00293             --_M_out_cur;
00294           __ret = traits_type::not_eof(__i);
00295         }
00296           else if (!__testeof)
00297         {
00298           --_M_in_cur;
00299           if (__testout)
00300             --_M_out_cur;
00301           _M_pback_create();
00302           *_M_in_cur = __c; 
00303           __ret = __i;
00304         }
00305         }
00306       else
00307         {    
00308           // At the beginning of the buffer, need to make a
00309           // putback position available.
00310           this->seekoff(-1, ios_base::cur);
00311           this->underflow();
00312           if (!__testeof)
00313         {
00314           if (!traits_type::eq(__c, *_M_in_cur))
00315             {
00316               _M_pback_create();
00317               *_M_in_cur = __c;
00318             }
00319           __ret = __i;
00320         }
00321           else
00322         __ret = traits_type::not_eof(__i);
00323         }
00324     }
00325       _M_last_overflowed = false;   
00326       return __ret;
00327     }
00328 
00329   template<typename _CharT, typename _Traits>
00330     typename basic_filebuf<_CharT, _Traits>::int_type 
00331     basic_filebuf<_CharT, _Traits>::
00332     overflow(int_type __c)
00333     {
00334       int_type __ret = traits_type::eof();
00335       bool __testput = _M_out_cur && _M_out_cur < _M_buf + _M_buf_size;
00336       bool __testout = _M_mode & ios_base::out;
00337       
00338       if (__testout)
00339     {
00340       if (__testput)
00341         {
00342           *_M_out_cur = traits_type::to_char_type(__c);
00343           _M_out_cur_move(1);
00344           __ret = traits_type::not_eof(__c);
00345         }
00346       else 
00347         __ret = this->_M_really_overflow(__c);
00348     }
00349 
00350       _M_last_overflowed = false;    // Set in _M_really_overflow, below.
00351       return __ret;
00352     }
00353   
00354   template<typename _CharT, typename _Traits>
00355     void
00356     basic_filebuf<_CharT, _Traits>::
00357     _M_convert_to_external(_CharT* __ibuf, streamsize __ilen,
00358                streamsize& __elen, streamsize& __plen)
00359     {
00360       const locale __loc = this->getloc();
00361       const __codecvt_type& __cvt = use_facet<__codecvt_type>(__loc);
00362       
00363       if (__cvt.always_noconv() && __ilen)
00364     {
00365       __elen += _M_file.xsputn(reinterpret_cast<char*>(__ibuf), __ilen);
00366       __plen += __ilen;
00367     }
00368       else
00369     {
00370       // Worst-case number of external bytes needed.
00371       int __ext_multiplier = __cvt.encoding();
00372       if (__ext_multiplier ==  -1 || __ext_multiplier == 0)
00373         __ext_multiplier = sizeof(char_type);
00374       streamsize __blen = __ilen * __ext_multiplier;
00375       char* __buf = static_cast<char*>(__builtin_alloca(__blen));
00376       char* __bend;
00377       const char_type* __iend;
00378       __res_type __r = __cvt.out(_M_state_cur, __ibuf, __ibuf + __ilen, 
00379                      __iend, __buf, __buf + __blen, __bend);
00380       // Result == ok, partial, noconv
00381       if (__r != codecvt_base::error)
00382         __blen = __bend - __buf;
00383       // Result == error
00384       else 
00385         __blen = 0;
00386       
00387       if (__blen)
00388         {
00389           __elen += _M_file.xsputn(__buf, __blen);
00390           __plen += __blen;
00391         }
00392 
00393       // Try once more for partial conversions.
00394       if (__r == codecvt_base::partial)
00395         {
00396           const char_type* __iresume = __iend;
00397           streamsize __rlen = _M_out_end - __iend;
00398           __r = __cvt.out(_M_state_cur, __iresume, __iresume + __rlen, 
00399                   __iend, __buf, __buf + __blen, __bend);
00400           if (__r != codecvt_base::error)
00401         __rlen = __bend - __buf;
00402           else 
00403         __rlen = 0;
00404           if (__rlen)
00405         {
00406           __elen += _M_file.xsputn(__buf, __rlen);
00407           __plen += __rlen;
00408         }
00409         }
00410     }
00411     }
00412 
00413   template<typename _CharT, typename _Traits>
00414     typename basic_filebuf<_CharT, _Traits>::int_type 
00415     basic_filebuf<_CharT, _Traits>::
00416     _M_really_overflow(int_type __c)
00417     {
00418       int_type __ret = traits_type::eof();
00419       bool __testput = _M_out_cur && _M_out_beg < _M_out_end;
00420       bool __testunbuffered = _M_file.is_open() && !_M_buf_size;
00421 
00422       if (__testput || __testunbuffered)
00423     {
00424       // Sizes of external and pending output.
00425       streamsize __elen = 0;
00426       streamsize __plen = 0;
00427 
00428       // Need to restore current position. The position of the external
00429       // byte sequence (_M_file) corresponds to _M_filepos, and we need
00430       // to move it to _M_out_beg for the write.
00431       if (_M_filepos && _M_filepos != _M_out_beg)
00432         {
00433           off_type __off = _M_out_beg - _M_filepos;
00434           _M_file.seekoff(__off, ios_base::cur);
00435         }
00436 
00437       // Convert internal buffer to external representation, output.
00438       // NB: In the unbuffered case, no internal buffer exists. 
00439       if (!__testunbuffered)
00440         _M_convert_to_external(_M_out_beg,  _M_out_end - _M_out_beg, 
00441                    __elen, __plen);
00442 
00443       // Convert pending sequence to external representation, output.
00444       // If eof, then just attempt sync.
00445       if (!traits_type::eq_int_type(__c, traits_type::eof()))
00446         {
00447           char_type __pending = traits_type::to_char_type(__c);
00448           _M_convert_to_external(&__pending, 1, __elen, __plen);
00449 
00450           // User code must flush when switching modes (thus don't sync).
00451           if (__elen == __plen)
00452         {
00453           _M_set_indeterminate();
00454           __ret = traits_type::not_eof(__c);
00455         }
00456         }
00457       else if (!_M_file.sync())
00458         {
00459           _M_set_indeterminate();
00460           __ret = traits_type::not_eof(__c);
00461         }
00462     }         
00463       _M_last_overflowed = true;    
00464       return __ret;
00465     }
00466 
00467   template<typename _CharT, typename _Traits>
00468     typename basic_filebuf<_CharT, _Traits>::__streambuf_type* 
00469     basic_filebuf<_CharT, _Traits>::
00470     setbuf(char_type* __s, streamsize __n)
00471     {
00472       if (!this->is_open() && __s == 0 && __n == 0)
00473     _M_buf_size_opt = 0;
00474       else if (__s && __n)
00475     {
00476       // This is implementation-defined behavior, and assumes
00477       // that an external char_type array of length (__s + __n)
00478       // exists and has been pre-allocated. If this is not the
00479       // case, things will quickly blow up.
00480       // Step 1: Destroy the current internal array.
00481       _M_destroy_internal_buffer();
00482       
00483       // Step 2: Use the external array.
00484       _M_buf = __s;
00485       _M_buf_size_opt = _M_buf_size = __n;
00486       _M_set_indeterminate();
00487     }
00488       _M_last_overflowed = false;   
00489       return this; 
00490     }
00491   
00492   template<typename _CharT, typename _Traits>
00493     typename basic_filebuf<_CharT, _Traits>::pos_type
00494     basic_filebuf<_CharT, _Traits>::
00495     seekoff(off_type __off, ios_base::seekdir __way, ios_base::openmode __mode)
00496     {
00497       pos_type __ret =  pos_type(off_type(-1)); 
00498       bool __testin = (ios_base::in & _M_mode & __mode) != 0;
00499       bool __testout = (ios_base::out & _M_mode & __mode) != 0;
00500 
00501       // Should probably do has_facet checks here.
00502       int __width = use_facet<__codecvt_type>(_M_buf_locale).encoding();
00503       if (__width < 0)
00504     __width = 0;
00505       bool __testfail = __off != 0 && __width <= 0;
00506       
00507       if (this->is_open() && !__testfail && (__testin || __testout)) 
00508     {
00509       // Ditch any pback buffers to avoid confusion.
00510       _M_pback_destroy();
00511 
00512       if (__way != ios_base::cur || __off != 0)
00513         { 
00514           off_type __computed_off = __width * __off;
00515           
00516           bool __testget = _M_in_cur && _M_in_beg < _M_in_end;
00517           bool __testput = _M_out_cur && _M_out_beg < _M_out_end;
00518           // Sync the internal and external streams.
00519           // out
00520           if (__testput || _M_last_overflowed)
00521         {
00522           // Part one: update the output sequence.
00523           this->sync();
00524           // Part two: output unshift sequence.
00525           _M_output_unshift();
00526         }
00527           //in
00528           else if (__testget && __way == ios_base::cur)
00529         __computed_off += _M_in_cur - _M_filepos;
00530       
00531           __ret = _M_file.seekoff(__computed_off, __way, __mode);
00532           _M_set_indeterminate();
00533         }
00534       // NB: Need to do this in case _M_file in indeterminate
00535       // state, ie _M_file._offset == -1
00536       else
00537         {
00538           __ret = _M_file.seekoff(__off, ios_base::cur, __mode);
00539           __ret += max(_M_out_cur, _M_in_cur) - _M_filepos;
00540         }
00541     }
00542       _M_last_overflowed = false;   
00543       return __ret;
00544     }
00545 
00546   template<typename _CharT, typename _Traits>
00547     typename basic_filebuf<_CharT, _Traits>::pos_type
00548     basic_filebuf<_CharT, _Traits>::
00549     seekpos(pos_type __pos, ios_base::openmode __mode)
00550     {
00551 #ifdef _GLIBCPP_RESOLVE_LIB_DEFECTS
00552 // 171. Strange seekpos() semantics due to joint position
00553       return this->seekoff(off_type(__pos), ios_base::beg, __mode);
00554 #endif
00555     }
00556 
00557   template<typename _CharT, typename _Traits>
00558     void 
00559     basic_filebuf<_CharT, _Traits>::
00560     _M_output_unshift()
00561     { }
00562 
00563   template<typename _CharT, typename _Traits>
00564     void
00565     basic_filebuf<_CharT, _Traits>::
00566     imbue(const locale& __loc)
00567     {
00568       bool __testbeg = gptr() == eback() && pptr() == pbase();
00569 
00570       if (__testbeg && _M_buf_locale != __loc)
00571     {
00572       _M_buf_locale = __loc;
00573       _M_buf_locale_init = true;
00574     }
00575 
00576       // NB this may require the reconversion of previously
00577       // converted chars. This in turn may cause the reconstruction
00578       // of the original file. YIKES!!
00579       // XXX The part in the above comment is not done.
00580       _M_last_overflowed = false;   
00581     }
00582 
00583   // Inhibit implicit instantiations for required instantiations,
00584   // which are defined via explicit instantiations elsewhere.  
00585   // NB:  This syntax is a GNU extension.
00586   extern template class basic_filebuf<char>;
00587   extern template class basic_filebuf<wchar_t>;
00588   extern template class basic_ifstream<char>;
00589   extern template class basic_ifstream<wchar_t>;
00590   extern template class basic_ofstream<char>;
00591   extern template class basic_ofstream<wchar_t>;
00592   extern template class basic_fstream<char>;
00593   extern template class basic_fstream<wchar_t>;
00594 } // namespace std
00595 
00596 #endif 

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