# fstream.tcc

    00001 // File based streams -*- C++ -*-
    00002
    00003 // Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003
    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       _M_buf = new char_type[_M_buf_size];
    00053       _M_buf_allocated = true;
    00054     }
    00055     }
    00056
    00057   // Both close and setbuf need to deallocate internal buffers, if it exists.
    00058   template<typename _CharT, typename _Traits>
    00059     void
    00060     basic_filebuf<_CharT, _Traits>::
    00061     _M_destroy_internal_buffer() throw()
    00062     {
    00063       if (_M_buf_allocated)
    00064     {
    00065       delete [] _M_buf;
    00066       _M_buf = NULL;
    00067       _M_buf_allocated = false;
    00068       this->setg(NULL, NULL, NULL);
    00069       this->setp(NULL, NULL);
    00070     }
    00071     }
    00072
    00073   template<typename _CharT, typename _Traits>
    00074     basic_filebuf<_CharT, _Traits>::
    00075     basic_filebuf() : __streambuf_type(), _M_file(&_M_lock),
    00076     _M_state_cur(__state_type()), _M_state_beg(__state_type()),
    00077     _M_buf_allocated(false), _M_last_overflowed(false)
    00078     { _M_buf_unified = true; }
    00079
    00080   template<typename _CharT, typename _Traits>
    00081     typename basic_filebuf<_CharT, _Traits>::__filebuf_type*
    00082     basic_filebuf<_CharT, _Traits>::
    00083     open(const char* __s, ios_base::openmode __mode)
    00084     {
    00085       __filebuf_type *__ret = NULL;
    00086       if (!this->is_open())
    00087     {
    00088       _M_file.open(__s, __mode);
    00089       if (this->is_open())
    00090         {
    00091           _M_allocate_internal_buffer();
    00092           _M_mode = __mode;
    00093
    00094           // Setup initial position of buffer.
    00095           _M_set_indeterminate();
    00096
    00097           // Set input buffer to something real.
    00098           // NB: Must open in non-blocking way to do this, or must
    00099           // set the initial position in a different manner than
    00100           // using underflow.
    00101           if (__mode & ios_base::in && _M_buf_allocated)
    00102         this->underflow();
    00103
    00104           if ((__mode & ios_base::ate)
    00105           && this->seekoff(0, ios_base::end, __mode) < 0)
    00106         {
    00107           // 27.8.1.3,4
    00108           this->close();
    00109           return __ret;
    00110         }
    00111
    00112           __ret = this;
    00113         }
    00114     }
    00115       return __ret;
    00116     }
    00117
    00118   template<typename _CharT, typename _Traits>
    00119     typename basic_filebuf<_CharT, _Traits>::__filebuf_type*
    00120     basic_filebuf<_CharT, _Traits>::
    00121     close() throw()
    00122     {
    00123       __filebuf_type* __ret = NULL;
    00124       if (this->is_open())
    00125     {
    00126       bool __testfail = false;
    00127       try
    00128         {
    00129           const int_type __eof = traits_type::eof();
    00130           bool __testput = _M_out_cur && _M_out_beg < _M_out_end;
    00131           if (__testput
    00132           && traits_type::eq_int_type(_M_really_overflow(__eof),
    00133                           __eof))
    00134         __testfail = true;
    00135
    00136 #if 0
    00137           // XXX not done
    00138           if (_M_last_overflowed)
    00139         {
    00140           _M_output_unshift();
    00141           _M_really_overflow(__eof);
    00142         }
    00143 #endif
    00144         }
    00145       catch(...)
    00146         {
    00147           __testfail = true;
    00148         }
    00149
    00150       // NB: Do this here so that re-opened filebufs will be cool...
    00151       this->_M_mode = ios_base::openmode(0);
    00152       _M_destroy_internal_buffer();
    00153       _M_pback_destroy();
    00154
    00155       if (!_M_file.close())
    00156         __testfail = true;
    00157
    00158       if (!__testfail)
    00159         __ret = this;
    00160     }
    00161       _M_last_overflowed = false;
    00162       return __ret;
    00163     }
    00164
    00165   template<typename _CharT, typename _Traits>
    00166     streamsize
    00167     basic_filebuf<_CharT, _Traits>::
    00168     showmanyc()
    00169     {
    00170       streamsize __ret = -1;
    00171       bool __testin = _M_mode & ios_base::in;
    00172
    00173       if (__testin && this->is_open())
    00174     __ret = _M_in_end - _M_in_cur;
    00175       _M_last_overflowed = false;
    00176       return __ret;
    00177     }
    00178
    00179   template<typename _CharT, typename _Traits>
    00180     typename basic_filebuf<_CharT, _Traits>::int_type
    00181     basic_filebuf<_CharT, _Traits>::
    00182     pbackfail(int_type __i)
    00183     {
    00184       int_type __ret = traits_type::eof();
    00185       bool __testin = _M_mode & ios_base::in;
    00186
    00187       if (__testin)
    00188     {
    00189       bool __testpb = _M_in_beg < _M_in_cur;
    00190       char_type __c = traits_type::to_char_type(__i);
    00191       bool __testeof = traits_type::eq_int_type(__i, __ret);
    00192
    00193       if (__testpb)
    00194         {
    00195           bool __testout = _M_mode & ios_base::out;
    00196           bool __testeq = traits_type::eq(__c, this->gptr()[-1]);
    00197
    00198           // Try to put back __c into input sequence in one of three ways.
    00199           // Order these tests done in is unspecified by the standard.
    00200           if (!__testeof && __testeq)
    00201         {
    00202           --_M_in_cur;
    00203           if (__testout)
    00204             --_M_out_cur;
    00205           __ret = __i;
    00206         }
    00207           else if (__testeof)
    00208         {
    00209           --_M_in_cur;
    00210           if (__testout)
    00211             --_M_out_cur;
    00212           __ret = traits_type::not_eof(__i);
    00213         }
    00214           else if (!__testeof)
    00215         {
    00216           --_M_in_cur;
    00217           if (__testout)
    00218             --_M_out_cur;
    00219           _M_pback_create();
    00220           *_M_in_cur = __c;
    00221           __ret = __i;
    00222         }
    00223         }
    00224       else
    00225         {
    00226           // At the beginning of the buffer, need to make a
    00227           // putback position available.
    00228           // But the seek may fail (f.i., at the beginning of
    00229           // a file, see libstdc++/9439) and in that case
    00230           // we return traits_type::eof()
    00231           if (this->seekoff(-1, ios_base::cur) >= 0)
    00232         {
    00233           this->underflow();
    00234           if (!__testeof)
    00235             {
    00236               if (!traits_type::eq(__c, *_M_in_cur))
    00237             {
    00238               _M_pback_create();
    00239               *_M_in_cur = __c;
    00240             }
    00241               __ret = __i;
    00242             }
    00243           else
    00244             __ret = traits_type::not_eof(__i);
    00245         }
    00246         }
    00247     }
    00248       _M_last_overflowed = false;
    00249       return __ret;
    00250     }
    00251
    00252   template<typename _CharT, typename _Traits>
    00253     typename basic_filebuf<_CharT, _Traits>::int_type
    00254     basic_filebuf<_CharT, _Traits>::
    00255     overflow(int_type __c)
    00256     {
    00257       int_type __ret = traits_type::eof();
    00258       bool __testput = _M_out_cur && _M_out_cur < _M_buf + _M_buf_size;
    00259       bool __testout = _M_mode & ios_base::out;
    00260
    00261       if (__testout)
    00262     {
    00263       if (traits_type::eq_int_type(__c, traits_type::eof()))
    00264         __ret = traits_type::not_eof(__c);
    00265       else if (__testput)
    00266         {
    00267           *_M_out_cur = traits_type::to_char_type(__c);
    00268           _M_out_cur_move(1);
    00269           __ret = traits_type::not_eof(__c);
    00270         }
    00271       else
    00272         __ret = this->_M_really_overflow(__c);
    00273     }
    00274
    00275       _M_last_overflowed = false;    // Set in _M_really_overflow, below.
    00276       return __ret;
    00277     }
    00278
    00279   template<typename _CharT, typename _Traits>
    00280     void
    00281     basic_filebuf<_CharT, _Traits>::
    00282     _M_convert_to_external(_CharT* __ibuf, streamsize __ilen,
    00283                streamsize& __elen, streamsize& __plen)
    00284     {
    00285       const locale __loc = this->getloc();
    00286       const __codecvt_type& __cvt = use_facet<__codecvt_type>(__loc);
    00287
    00288       if (__cvt.always_noconv() && __ilen)
    00289     {
    00290       __elen += _M_file.xsputn(reinterpret_cast<char*>(__ibuf), __ilen);
    00291       __plen += __ilen;
    00292     }
    00293       else
    00294     {
    00295       // Worst-case number of external bytes needed.
    00296       int __ext_multiplier = __cvt.encoding();
    00297       if (__ext_multiplier ==  -1 || __ext_multiplier == 0)
    00298         __ext_multiplier = sizeof(char_type);
    00299       streamsize __blen = __ilen * __ext_multiplier;
    00300       char* __buf = static_cast<char*>(__builtin_alloca(__blen));
    00301       char* __bend;
    00302       const char_type* __iend;
    00303       codecvt_base::result __r;
    00304       __r = __cvt.out(_M_state_cur, __ibuf, __ibuf + __ilen,
    00305               __iend, __buf, __buf + __blen, __bend);
    00306
    00307       if (__r == codecvt_base::ok || __r == codecvt_base::partial)
    00308         __blen = __bend - __buf;
    00309       else if (__r == codecvt_base::noconv)
    00310         {
    00311           // Same as the always_noconv case above.
    00312           __buf = reinterpret_cast<char*>(__ibuf);
    00313           __blen = __ilen;
    00314         }
    00315       else
    00316         {
    00317           // Result == error
    00318           __blen = 0;
    00319         }
    00320
    00321       if (__blen)
    00322         {
    00323           __elen += _M_file.xsputn(__buf, __blen);
    00324           __plen += __blen;
    00325         }
    00326
    00327       // Try once more for partial conversions.
    00328       if (__r == codecvt_base::partial)
    00329         {
    00330           const char_type* __iresume = __iend;
    00331           streamsize __rlen = _M_out_end - __iend;
    00332           __r = __cvt.out(_M_state_cur, __iresume, __iresume + __rlen,
    00333                   __iend, __buf, __buf + __blen, __bend);
    00334           if (__r != codecvt_base::error)
    00335         {
    00336           __rlen = __bend - __buf;
    00337           __elen += _M_file.xsputn(__buf, __rlen);
    00338           __plen += __rlen;
    00339         }
    00340         }
    00341     }
    00342     }
    00343
    00344   template<typename _CharT, typename _Traits>
    00345     typename basic_filebuf<_CharT, _Traits>::int_type
    00346     basic_filebuf<_CharT, _Traits>::
    00347     _M_really_overflow(int_type __c)
    00348     {
    00349       int_type __ret = traits_type::eof();
    00350       bool __testput = _M_out_cur && _M_out_beg < _M_out_end;
    00351       bool __testunbuffered = _M_file.is_open() && !_M_buf_size;
    00352
    00353       if (__testput || __testunbuffered)
    00354     {
    00355       // Sizes of external and pending output.
    00356       streamsize __elen = 0;
    00357       streamsize __plen = 0;
    00358
    00359       // Need to restore current position. The position of the external
    00360       // byte sequence (_M_file) corresponds to _M_filepos, and we need
    00361       // to move it to _M_out_beg for the write.
    00362       if (_M_filepos && _M_filepos != _M_out_beg)
    00363         {
    00364           off_type __off = _M_out_beg - _M_filepos;
    00365           _M_file.seekoff(__off, ios_base::cur);
    00366         }
    00367
    00368       // Convert internal buffer to external representation, output.
    00369       // NB: In the unbuffered case, no internal buffer exists.
    00370       if (!__testunbuffered)
    00371         _M_convert_to_external(_M_out_beg,  _M_out_end - _M_out_beg,
    00372                    __elen, __plen);
    00373
    00374       // Checks for codecvt.out failures and _M_file.xsputn failures,
    00375       // respectively, inside _M_convert_to_external.
    00376       if (__testunbuffered || (__elen && __elen == __plen))
    00377         {
    00378           // Convert pending sequence to external representation, output.
    00379           // If eof, then just attempt sync.
    00380           if (!traits_type::eq_int_type(__c, traits_type::eof()))
    00381         {
    00382           char_type __pending = traits_type::to_char_type(__c);
    00383           _M_convert_to_external(&__pending, 1, __elen, __plen);
    00384
    00385           // User code must flush when switching modes (thus
    00386           // don't sync).
    00387           if (__elen == __plen && __elen)
    00388             {
    00389               _M_set_indeterminate();
    00390               __ret = traits_type::not_eof(__c);
    00391             }
    00392         }
    00393           else if (!_M_file.sync())
    00394         {
    00395           _M_set_indeterminate();
    00396           __ret = traits_type::not_eof(__c);
    00397         }
    00398         }
    00399     }
    00400       _M_last_overflowed = true;
    00401       return __ret;
    00402     }
    00403
    00404   template<typename _CharT, typename _Traits>
    00405     typename basic_filebuf<_CharT, _Traits>::__streambuf_type*
    00406     basic_filebuf<_CharT, _Traits>::
    00407     setbuf(char_type* __s, streamsize __n)
    00408     {
    00409       if (!this->is_open() && __s == 0 && __n == 0)
    00410     _M_buf_size_opt = 0;
    00411       else if (__s && __n)
    00412     {
    00413       // This is implementation-defined behavior, and assumes
    00414       // that an external char_type array of length (__s + __n)
    00415       // exists and has been pre-allocated. If this is not the
    00416       // case, things will quickly blow up.
    00417       // Step 1: Destroy the current internal array.
    00418       _M_destroy_internal_buffer();
    00419
    00420       // Step 2: Use the external array.
    00421       _M_buf = __s;
    00422       _M_buf_size_opt = _M_buf_size = __n;
    00423       _M_set_indeterminate();
    00424     }
    00425       _M_last_overflowed = false;
    00426       return this;
    00427     }
    00428
    00429   template<typename _CharT, typename _Traits>
    00430     typename basic_filebuf<_CharT, _Traits>::pos_type
    00431     basic_filebuf<_CharT, _Traits>::
    00432     seekoff(off_type __off, ios_base::seekdir __way, ios_base::openmode __mode)
    00433     {
    00434       pos_type __ret =  pos_type(off_type(-1));
    00435       bool __testin = (ios_base::in & _M_mode & __mode) != 0;
    00436       bool __testout = (ios_base::out & _M_mode & __mode) != 0;
    00437
    00438       int __width = 0;
    00439       if (has_facet<__codecvt_type>(this->_M_buf_locale))
    00440       __width = use_facet<__codecvt_type>(this->_M_buf_locale).encoding();
    00441       if (__width < 0)
    00442     __width = 0;
    00443
    00444       bool __testfail = __off != 0 && __width <= 0;
    00445       if (this->is_open() && !__testfail && (__testin || __testout))
    00446     {
    00447       // Ditch any pback buffers to avoid confusion.
    00448       _M_pback_destroy();
    00449
    00450       if (__way != ios_base::cur || __off != 0)
    00451         {
    00452           off_type __computed_off = __width * __off;
    00453
    00454           bool __testget = _M_in_cur && _M_in_beg < _M_in_end;
    00455           bool __testput = _M_out_cur && _M_out_beg < _M_out_end;
    00456           // Sync the internal and external streams.
    00457           // out
    00458           if (__testput || _M_last_overflowed)
    00459         {
    00460           // Part one: update the output sequence.
    00461           this->sync();
    00462           // Part two: output unshift sequence.
    00463           _M_output_unshift();
    00464         }
    00465           //in
    00466           else if (__testget && __way == ios_base::cur)
    00467         __computed_off += _M_in_cur - _M_filepos;
    00468
    00469           // Return pos_type(off_type(-1)) in case of failure.
    00470           __ret = _M_file.seekoff(__computed_off, __way, __mode);
    00471           _M_set_indeterminate();
    00472         }
    00473       // NB: Need to do this in case _M_file in indeterminate
    00474       // state, ie _M_file._offset == -1
    00475       else
    00476         {
    00477           pos_type __tmp =
    00478         _M_file.seekoff(__off, ios_base::cur, __mode);
    00479           if (__tmp >= 0)
    00480         {
    00481           // Seek successful.
    00482           __ret = __tmp;
    00483           __ret += max(_M_out_cur, _M_in_cur) - _M_filepos;
    00484         }
    00485         }
    00486     }
    00487       _M_last_overflowed = false;
    00488       return __ret;
    00489     }
    00490
    00491   template<typename _CharT, typename _Traits>
    00492     typename basic_filebuf<_CharT, _Traits>::pos_type
    00493     basic_filebuf<_CharT, _Traits>::
    00494     seekpos(pos_type __pos, ios_base::openmode __mode)
    00495     {
    00496 #ifdef _GLIBCPP_RESOLVE_LIB_DEFECTS
    00497 // 171. Strange seekpos() semantics due to joint position
    00498       return this->seekoff(off_type(__pos), ios_base::beg, __mode);
    00499 #endif
    00500     }
    00501
    00502   template<typename _CharT, typename _Traits>
    00503     void
    00504     basic_filebuf<_CharT, _Traits>::
    00505     _M_output_unshift()
    00506     { }
    00507
    00508   template<typename _CharT, typename _Traits>
    00509     void
    00510     basic_filebuf<_CharT, _Traits>::
    00511     imbue(const locale& __loc)
    00512     {
    00513       bool __testbeg = gptr() == eback() && pptr() == pbase();
    00514
    00515       if (__testbeg && _M_buf_locale != __loc)
    00516     _M_buf_locale = __loc;
    00517
    00518       // NB this may require the reconversion of previously
    00519       // converted chars. This in turn may cause the reconstruction
    00520       // of the original file. YIKES!!
    00521       // XXX The part in the above comment is not done.
    00522       _M_last_overflowed = false;
    00523     }
    00524
    00525   // Inhibit implicit instantiations for required instantiations,
    00526   // which are defined via explicit instantiations elsewhere.
    00527   // NB:  This syntax is a GNU extension.
    00528 #if _GLIBCPP_EXTERN_TEMPLATE
    00529   extern template class basic_filebuf<char>;
    00530   extern template class basic_ifstream<char>;
    00531   extern template class basic_ofstream<char>;
    00532   extern template class basic_fstream<char>;
    00533
    00534 #ifdef _GLIBCPP_USE_WCHAR_T
    00535   extern template class basic_filebuf<wchar_t>;
    00536   extern template class basic_ifstream<wchar_t>;
    00537   extern template class basic_ofstream<wchar_t>;
    00538   extern template class basic_fstream<wchar_t>;
    00539 #endif
    00540 #endif
    00541 } // namespace std
    00542
    00543 #endif