ios.cc

00001 // Iostreams base classes -*- 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: 27.4  Iostreams base classes
00033 //
00034 
00035 #include <ios>
00036 #include <ostream>
00037 #include <istream>
00038 #include <fstream>
00039 #include <bits/atomicity.h>
00040 #include <ext/stdio_filebuf.h>
00041 #ifdef _GLIBCPP_HAVE_UNISTD_H
00042 #include <unistd.h>
00043 #endif
00044 
00045 namespace __gnu_cxx
00046 {
00047   // Extern declarations for global objects in src/globals.cc.
00048   extern stdio_filebuf<char> buf_cout;
00049   extern stdio_filebuf<char> buf_cin;
00050   extern stdio_filebuf<char> buf_cerr;
00051 
00052 #ifdef _GLIBCPP_USE_WCHAR_T
00053   extern stdio_filebuf<wchar_t> buf_wcout;
00054   extern stdio_filebuf<wchar_t> buf_wcin;
00055   extern stdio_filebuf<wchar_t> buf_wcerr;
00056 #endif
00057 } // namespace __gnu_cxx
00058 
00059 namespace std 
00060 {
00061   using namespace __gnu_cxx;
00062   
00063   extern istream cin;
00064   extern ostream cout;
00065   extern ostream cerr;
00066   extern ostream clog;
00067 
00068 #ifdef _GLIBCPP_USE_WCHAR_T
00069   extern wistream wcin;
00070   extern wostream wcout;
00071   extern wostream wcerr;
00072   extern wostream wclog;
00073 #endif
00074 
00075   // Definitions for static const data members of __ios_flags.
00076   const __ios_flags::__int_type __ios_flags::_S_boolalpha;
00077   const __ios_flags::__int_type __ios_flags::_S_dec;
00078   const __ios_flags::__int_type __ios_flags::_S_fixed;
00079   const __ios_flags::__int_type __ios_flags::_S_hex;
00080   const __ios_flags::__int_type __ios_flags::_S_internal;
00081   const __ios_flags::__int_type __ios_flags::_S_left;
00082   const __ios_flags::__int_type __ios_flags::_S_oct;
00083   const __ios_flags::__int_type __ios_flags::_S_right;
00084   const __ios_flags::__int_type __ios_flags::_S_scientific;
00085   const __ios_flags::__int_type __ios_flags::_S_showbase;
00086   const __ios_flags::__int_type __ios_flags::_S_showpoint;
00087   const __ios_flags::__int_type __ios_flags::_S_showpos;
00088   const __ios_flags::__int_type __ios_flags::_S_skipws;
00089   const __ios_flags::__int_type __ios_flags::_S_unitbuf;
00090   const __ios_flags::__int_type __ios_flags::_S_uppercase;
00091   const __ios_flags::__int_type __ios_flags::_S_adjustfield;
00092   const __ios_flags::__int_type __ios_flags::_S_basefield;
00093   const __ios_flags::__int_type __ios_flags::_S_floatfield;
00094 
00095   const __ios_flags::__int_type __ios_flags::_S_badbit;
00096   const __ios_flags::__int_type __ios_flags::_S_eofbit;
00097   const __ios_flags::__int_type __ios_flags::_S_failbit;
00098 
00099   const __ios_flags::__int_type __ios_flags::_S_app;
00100   const __ios_flags::__int_type __ios_flags::_S_ate;
00101   const __ios_flags::__int_type __ios_flags::_S_bin;
00102   const __ios_flags::__int_type __ios_flags::_S_in;
00103   const __ios_flags::__int_type __ios_flags::_S_out;
00104   const __ios_flags::__int_type __ios_flags::_S_trunc;
00105 
00106   // Definitions for static const members of ios_base.
00107   const ios_base::fmtflags ios_base::boolalpha;
00108   const ios_base::fmtflags ios_base::dec;
00109   const ios_base::fmtflags ios_base::fixed;
00110   const ios_base::fmtflags ios_base::hex;
00111   const ios_base::fmtflags ios_base::internal;
00112   const ios_base::fmtflags ios_base::left;
00113   const ios_base::fmtflags ios_base::oct;
00114   const ios_base::fmtflags ios_base::right;
00115   const ios_base::fmtflags ios_base::scientific;
00116   const ios_base::fmtflags ios_base::showbase;
00117   const ios_base::fmtflags ios_base::showpoint;
00118   const ios_base::fmtflags ios_base::showpos;
00119   const ios_base::fmtflags ios_base::skipws;
00120   const ios_base::fmtflags ios_base::unitbuf;
00121   const ios_base::fmtflags ios_base::uppercase;
00122   const ios_base::fmtflags ios_base::adjustfield;
00123   const ios_base::fmtflags ios_base::basefield;
00124   const ios_base::fmtflags ios_base::floatfield;
00125 
00126   const ios_base::iostate ios_base::badbit;
00127   const ios_base::iostate ios_base::eofbit;
00128   const ios_base::iostate ios_base::failbit;
00129   const ios_base::iostate ios_base::goodbit;
00130 
00131   const ios_base::openmode ios_base::app;
00132   const ios_base::openmode ios_base::ate;
00133   const ios_base::openmode ios_base::binary;
00134   const ios_base::openmode ios_base::in;
00135   const ios_base::openmode ios_base::out;
00136   const ios_base::openmode ios_base::trunc;
00137 
00138   const ios_base::seekdir ios_base::beg;
00139   const ios_base::seekdir ios_base::cur;
00140   const ios_base::seekdir ios_base::end;
00141 
00142   const int ios_base::_S_local_word_size;
00143   int ios_base::Init::_S_ios_base_init = 0;
00144   bool ios_base::Init::_S_synced_with_stdio = true;
00145 
00146   ios_base::failure::failure(const string& __str) throw()
00147   {
00148     strncpy(_M_name, __str.c_str(), _M_bufsize);
00149     _M_name[_M_bufsize - 1] = '\0';
00150   }
00151 
00152   ios_base::failure::~failure() throw()
00153   { }
00154 
00155   const char*
00156   ios_base::failure::what() const throw()
00157   { return _M_name; }
00158 
00159   void
00160   ios_base::Init::_S_ios_create(bool __sync)
00161   {
00162     int __out_size = __sync ? 0 : static_cast<int>(BUFSIZ);
00163 #ifdef _GLIBCPP_HAVE_ISATTY
00164     int __in_size = (__sync || isatty (0)) ? 1 : static_cast<int>(BUFSIZ);
00165 #else
00166     int __in_size = 1;
00167 #endif
00168 
00169     // NB: The file globals.cc creates the four standard files
00170     // with NULL buffers. At this point, we swap out the dummy NULL
00171     // [io]stream objects and buffers with the real deal.
00172     new (&buf_cout) stdio_filebuf<char>(stdout, ios_base::out, __out_size);
00173     new (&buf_cin) stdio_filebuf<char>(stdin, ios_base::in, __in_size);
00174     new (&buf_cerr) stdio_filebuf<char>(stderr, ios_base::out, __out_size);
00175     new (&cout) ostream(&buf_cout);
00176     new (&cin) istream(&buf_cin);
00177     new (&cerr) ostream(&buf_cerr);
00178     new (&clog) ostream(&buf_cerr);
00179     cin.tie(&cout);
00180     cerr.flags(ios_base::unitbuf);
00181     
00182 #ifdef _GLIBCPP_USE_WCHAR_T
00183     new (&buf_wcout) stdio_filebuf<wchar_t>(stdout, ios_base::out, __out_size);
00184     new (&buf_wcin) stdio_filebuf<wchar_t>(stdin, ios_base::in, __in_size);
00185     new (&buf_wcerr) stdio_filebuf<wchar_t>(stderr, ios_base::out, __out_size);
00186     new (&wcout) wostream(&buf_wcout);
00187     new (&wcin) wistream(&buf_wcin);
00188     new (&wcerr) wostream(&buf_wcerr);
00189     new (&wclog) wostream(&buf_wcerr);
00190     wcin.tie(&wcout);
00191     wcerr.flags(ios_base::unitbuf);
00192 #endif
00193   }
00194 
00195   void
00196   ios_base::Init::_S_ios_destroy()
00197   {
00198     // Explicitly call dtors to free any memory that is dynamically
00199     // allocated by filebuf ctor or member functions, but don't
00200     // deallocate all memory by calling operator delete.
00201     buf_cout.~stdio_filebuf();
00202     buf_cin.~stdio_filebuf();
00203     buf_cerr.~stdio_filebuf();
00204 
00205 #ifdef _GLIBCPP_USE_WCHAR_T
00206     buf_wcout.~stdio_filebuf();
00207     buf_wcin.~stdio_filebuf();
00208     buf_wcerr.~stdio_filebuf();
00209 #endif
00210   }
00211 
00212   ios_base::Init::Init()
00213   {
00214     if (_S_ios_base_init == 0)
00215       {
00216     // Standard streams default to synced with "C" operations.
00217     ios_base::Init::_S_synced_with_stdio = true;
00218     _S_ios_create(ios_base::Init::_S_synced_with_stdio);
00219       }
00220     ++_S_ios_base_init;
00221   }
00222 
00223   ios_base::Init::~Init()
00224   {
00225     if (--_S_ios_base_init == 0)
00226       _S_ios_destroy();
00227   } 
00228 
00229   // 27.4.2.5  ios_base storage functions
00230   int 
00231   ios_base::xalloc() throw()
00232   {
00233     // Implementation note: Initialize top to zero to ensure that
00234     // initialization occurs before main() is started.
00235     static _Atomic_word _S_top = 0; 
00236     return __exchange_and_add(&_S_top, 1) + 4;
00237   }
00238 
00239   // 27.4.2.5  iword/pword storage
00240   ios_base::_Words&
00241   ios_base::_M_grow_words(int ix)
00242   {
00243     // Precondition: _M_word_size <= ix
00244     int newsize = _S_local_word_size;
00245     _Words* words = _M_local_word;
00246     if (ix > _S_local_word_size - 1)
00247       {
00248     if (ix < numeric_limits<int>::max())
00249       {
00250         newsize = ix + 1;
00251         try
00252           { words = new _Words[newsize]; }
00253         catch (...)
00254           {
00255         delete [] _M_word;
00256         _M_word = 0;
00257         _M_streambuf_state |= badbit;
00258         if (_M_streambuf_state & _M_exception)
00259           __throw_ios_failure("ios_base::_M_grow_words failure");
00260         return _M_word_zero;
00261           }
00262         for (int i = 0; i < _M_word_size; i++) 
00263           words[i] = _M_word[i];
00264         if (_M_word && _M_word != _M_local_word) 
00265           {
00266         delete [] _M_word;
00267         _M_word = 0;
00268           }
00269       }
00270     else
00271       {
00272         _M_streambuf_state |= badbit;
00273         return _M_word_zero;
00274       }
00275       }
00276     _M_word = words;
00277     _M_word_size = newsize;
00278     return _M_word[ix];
00279   }
00280   
00281   // Called only by basic_ios<>::init.
00282   void 
00283   ios_base::_M_init()   
00284   {
00285     // NB: May be called more than once
00286     _M_precision = 6;
00287     _M_width = 0;
00288     _M_flags = skipws | dec;
00289     _M_callbacks = 0;
00290     _M_word_size = 0;
00291     _M_ios_locale = locale();
00292   }  
00293   
00294   // 27.4.2.3  ios_base locale functions
00295   locale
00296   ios_base::imbue(const locale& __loc)
00297   {
00298     locale __old = _M_ios_locale;
00299     _M_ios_locale = __loc;
00300     _M_call_callbacks(imbue_event);
00301     return __old;
00302   }
00303 
00304   ios_base::ios_base() : _M_callbacks(0), _M_word(0)
00305   {
00306     // Do nothing: basic_ios::init() does it.  
00307     // NB: _M_callbacks and _M_word must be zero for non-initialized
00308     // ios_base to go through ~ios_base gracefully.
00309   }
00310   
00311   // 27.4.2.7  ios_base constructors/destructors
00312   ios_base::~ios_base()
00313   {
00314     _M_call_callbacks(erase_event);
00315     _M_dispose_callbacks();
00316     if (_M_word && _M_word != _M_local_word) 
00317       {
00318     delete [] _M_word;
00319     _M_word = 0;
00320       }
00321   }
00322 
00323   void 
00324   ios_base::register_callback(event_callback __fn, int __index)
00325   { _M_callbacks = new _Callback_list(__fn, __index, _M_callbacks); }
00326 
00327   void 
00328   ios_base::_M_call_callbacks(event __e) throw()
00329   {
00330     _Callback_list* __p = _M_callbacks;
00331     while (__p)
00332       {
00333     try 
00334       { (*__p->_M_fn) (__e, *this, __p->_M_index); } 
00335     catch (...) 
00336       { }
00337     __p = __p->_M_next;
00338       }
00339   }
00340 
00341   void 
00342   ios_base::_M_dispose_callbacks(void)
00343   {
00344     _Callback_list* __p = _M_callbacks;
00345     while (__p && __p->_M_remove_reference() == 0)
00346       {
00347     _Callback_list* __next = __p->_M_next;
00348     delete __p;
00349     __p = __next;
00350       }
00351     _M_callbacks = 0;
00352   }
00353 
00354   bool 
00355   ios_base::sync_with_stdio(bool __sync)
00356   { 
00357 #ifdef _GLIBCPP_RESOLVE_LIB_DEFECTS
00358     // 49.  Underspecification of ios_base::sync_with_stdio
00359     bool __ret = ios_base::Init::_S_synced_with_stdio;
00360 #endif
00361 
00362     // Turn off sync with C FILE* for cin, cout, cerr, clog iff
00363     // currently synchronized.
00364     if (!__sync && __ret)
00365       {
00366     ios_base::Init::_S_synced_with_stdio = false;
00367     ios_base::Init::_S_ios_destroy();
00368     ios_base::Init::_S_ios_create(ios_base::Init::_S_synced_with_stdio);
00369       }
00370     return __ret; 
00371   }
00372 }  // namespace std

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