# 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