libstdc++-v3/src/ios.cc

   1 // Iostreams base classes -*- C++ -*-
   2
   3 // Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002
   4 // Free Software Foundation, Inc.
   5 //
   6 // This file is part of the GNU ISO C++ Library.  This library is free
   7 // software; you can redistribute it and/or modify it under the
   8 // terms of the GNU General Public License as published by the
   9 // Free Software Foundation; either version 2, or (at your option)
  10 // any later version.
  11
  12 // This library is distributed in the hope that it will be useful,
  13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 // GNU General Public License for more details.
  16
  17 // You should have received a copy of the GNU General Public License along
  18 // with this library; see the file COPYING.  If not, write to the Free
  19 // Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
  20 // USA.
  21
  22 // As a special exception, you may use this file as part of a free software
  23 // library without restriction.  Specifically, if other files instantiate
  24 // templates or use macros or inline functions from this file, or you compile
  25 // this file and link it with other files to produce an executable, this
  26 // file does not by itself cause the resulting executable to be covered by
  27 // the GNU General Public License.  This exception does not however
  28 // invalidate any other reasons why the executable file might be covered by
  29 // the GNU General Public License.
  30
  31 //
  32 // ISO C++ 14882: 27.4  Iostreams base classes
  33 //
  34
  35 #include <ios>
  36 #include <ostream>
  37 #include <istream>
  38 #include <fstream>
  39
  40 #include <bits/atomicity.h>
  41
  42 namespace std
  43 {
  44   // Extern declarations for global objects in src/globals.cc.
  45   extern istream cin;
  46   extern ostream cout;
  47   extern ostream cerr;
  48   extern ostream clog;
  49   extern filebuf buf_cout;
  50   extern filebuf buf_cin;
  51   extern filebuf buf_cerr;
  52
  53 #ifdef _GLIBCPP_USE_WCHAR_T
  54   extern wistream wcin;
  55   extern wostream wcout;
  56   extern wostream wcerr;
  57   extern wostream wclog;
  58   extern wfilebuf buf_wcout;
  59   extern wfilebuf buf_wcin;
  60   extern wfilebuf buf_wcerr;
  61 #endif
  62
  63   // Definitions for static const data members of __ios_flags.
  64   const __ios_flags::__int_type __ios_flags::_S_boolalpha;
  65   const __ios_flags::__int_type __ios_flags::_S_dec;
  66   const __ios_flags::__int_type __ios_flags::_S_fixed;
  67   const __ios_flags::__int_type __ios_flags::_S_hex;
  68   const __ios_flags::__int_type __ios_flags::_S_internal;
  69   const __ios_flags::__int_type __ios_flags::_S_left;
  70   const __ios_flags::__int_type __ios_flags::_S_oct;
  71   const __ios_flags::__int_type __ios_flags::_S_right;
  72   const __ios_flags::__int_type __ios_flags::_S_scientific;
  73   const __ios_flags::__int_type __ios_flags::_S_showbase;
  74   const __ios_flags::__int_type __ios_flags::_S_showpoint;
  75   const __ios_flags::__int_type __ios_flags::_S_showpos;
  76   const __ios_flags::__int_type __ios_flags::_S_skipws;
  77   const __ios_flags::__int_type __ios_flags::_S_unitbuf;
  78   const __ios_flags::__int_type __ios_flags::_S_uppercase;
  79   const __ios_flags::__int_type __ios_flags::_S_adjustfield;
  80   const __ios_flags::__int_type __ios_flags::_S_basefield;
  81   const __ios_flags::__int_type __ios_flags::_S_floatfield;
  82
  83   const __ios_flags::__int_type __ios_flags::_S_badbit;
  84   const __ios_flags::__int_type __ios_flags::_S_eofbit;
  85   const __ios_flags::__int_type __ios_flags::_S_failbit;
  86
  87   const __ios_flags::__int_type __ios_flags::_S_app;
  88   const __ios_flags::__int_type __ios_flags::_S_ate;
  89   const __ios_flags::__int_type __ios_flags::_S_bin;
  90   const __ios_flags::__int_type __ios_flags::_S_in;
  91   const __ios_flags::__int_type __ios_flags::_S_out;
  92   const __ios_flags::__int_type __ios_flags::_S_trunc;
  93
  94   // Definitions for static const members of ios_base.
  95   const ios_base::fmtflags ios_base::boolalpha;
  96   const ios_base::fmtflags ios_base::dec;
  97   const ios_base::fmtflags ios_base::fixed;
  98   const ios_base::fmtflags ios_base::hex;
  99   const ios_base::fmtflags ios_base::internal;
 100   const ios_base::fmtflags ios_base::left;
 101   const ios_base::fmtflags ios_base::oct;
 102   const ios_base::fmtflags ios_base::right;
 103   const ios_base::fmtflags ios_base::scientific;
 104   const ios_base::fmtflags ios_base::showbase;
 105   const ios_base::fmtflags ios_base::showpoint;
 106   const ios_base::fmtflags ios_base::showpos;
 107   const ios_base::fmtflags ios_base::skipws;
 108   const ios_base::fmtflags ios_base::unitbuf;
 109   const ios_base::fmtflags ios_base::uppercase;
 110   const ios_base::fmtflags ios_base::adjustfield;
 111   const ios_base::fmtflags ios_base::basefield;
 112   const ios_base::fmtflags ios_base::floatfield;
 113
 114   const ios_base::iostate ios_base::badbit;
 115   const ios_base::iostate ios_base::eofbit;
 116   const ios_base::iostate ios_base::failbit;
 117   const ios_base::iostate ios_base::goodbit;
 118
 119   const ios_base::openmode ios_base::app;
 120   const ios_base::openmode ios_base::ate;
 121   const ios_base::openmode ios_base::binary;
 122   const ios_base::openmode ios_base::in;
 123   const ios_base::openmode ios_base::out;
 124   const ios_base::openmode ios_base::trunc;
 125
 126   const ios_base::seekdir ios_base::beg;
 127   const ios_base::seekdir ios_base::cur;
 128   const ios_base::seekdir ios_base::end;
 129
 130   const int ios_base::_S_local_words;
 131   int ios_base::Init::_S_ios_base_init = 0;
 132   bool ios_base::Init::_S_synced_with_stdio = true;
 133
 134   ios_base::failure::failure(const string& __str) throw()
 135   {
 136     strncpy(_M_name, __str.c_str(), _M_bufsize);
 137     _M_name[_M_bufsize - 1] = '\0';
 138   }
 139
 140   ios_base::failure::~failure() throw()
 141   { }
 142
 143   const char*
 144   ios_base::failure::what() const throw()
 145   { return _M_name; }
 146
 147   void
 148   ios_base::Init::_S_ios_create(bool __sync)
 149   {
 150     int __out_bufsize = __sync ? 0 : static_cast<int>(BUFSIZ);
 151     int __in_bufsize = __sync ? 1 : static_cast<int>(BUFSIZ);
 152
 153 #if _GLIBCPP_AVOID_FSEEK
 154     // Platforms that prefer to avoid fseek() calls on streams only
 155     // get their desire when the C++-layer input buffer size is 1.
 156     // This hack hurts performance but keeps correctness across
 157     // all types of streams that might be attached to (e.g.) cin.
 158     __in_bufsize = 1;
 159 #endif
 160
 161     // NB: The file globals.cc creates the four standard files
 162     // with NULL buffers. At this point, we swap out the dummy NULL
 163     // [io]stream objects and buffers with the real deal.
 164     new (&buf_cout) filebuf(stdout, ios_base::out, __out_bufsize);
 165     new (&buf_cin) filebuf(stdin, ios_base::in, __in_bufsize);
 166     new (&buf_cerr) filebuf(stderr, ios_base::out, __out_bufsize);
 167     new (&cout) ostream(&buf_cout);
 168     new (&cin) istream(&buf_cin);
 169     new (&cerr) ostream(&buf_cerr);
 170     new (&clog) ostream(&buf_cerr);
 171     cin.tie(&cout);
 172     cerr.flags(ios_base::unitbuf);
 173
 174 #ifdef _GLIBCPP_USE_WCHAR_T
 175     new (&buf_wcout) wfilebuf(stdout, ios_base::out, __out_bufsize);
 176     new (&buf_wcin) wfilebuf(stdin, ios_base::in, __in_bufsize);
 177     new (&buf_wcerr) wfilebuf(stderr, ios_base::out, __out_bufsize);
 178     new (&wcout) wostream(&buf_wcout);
 179     new (&wcin) wistream(&buf_wcin);
 180     new (&wcerr) wostream(&buf_wcerr);
 181     new (&wclog) wostream(&buf_wcerr);
 182     wcin.tie(&wcout);
 183     wcerr.flags(ios_base::unitbuf);
 184 #endif
 185   }
 186
 187   void
 188   ios_base::Init::_S_ios_destroy()
 189   {
 190     // Explicitly call dtors to free any memory that is dynamically
 191     // allocated by filebuf ctor or member functions, but don't
 192     // deallocate all memory by calling operator delete.
 193     cout.flush();
 194     cerr.flush();
 195     clog.flush();
 196     buf_cout.~filebuf();
 197     buf_cin.~filebuf();
 198     buf_cerr.~filebuf();
 199 #ifdef _GLIBCPP_USE_WCHAR_T
 200     wcout.flush();
 201     wcerr.flush();
 202     wclog.flush();
 203     buf_wcout.~wfilebuf();
 204     buf_wcin.~wfilebuf();
 205     buf_wcerr.~wfilebuf();
 206 #endif
 207   }
 208
 209   ios_base::Init::Init()
 210   {
 211     if (_S_ios_base_init == 0)
 212       {
 213         // Standard streams default to synced with "C" operations.
 214         ios_base::Init::_S_synced_with_stdio = true;
 215         _S_ios_create(ios_base::Init::_S_synced_with_stdio);
 216       }
 217     ++_S_ios_base_init;
 218   }
 219
 220   ios_base::Init::~Init()
 221   {
 222     if (--_S_ios_base_init == 0)
 223       _S_ios_destroy();
 224   }
 225
 226   // 27.4.2.5  ios_base storage functions
 227   int
 228   ios_base::xalloc() throw()
 229   {
 230     // XXX should be a symbol. (Reserve 0..3 for builtins.)
 231     static _Atomic_word top = 0;
 232     return __exchange_and_add(&top, 1) + 4;
 233     // Implementation note: Initialize top to zero to ensure that
 234     // initialization occurs before main() is started.
 235   }
 236
 237   // 27.4.2.5  iword/pword storage
 238   ios_base::_Words&
 239   ios_base::_M_grow_words(int ix)
 240   {
 241     // Precondition: _M_word_limit <= ix
 242     _Words zero = { 0, 0 };
 243     int newlimit = _S_local_words;
 244     _Words* words = _M_word_array;
 245     int i = 0;
 246     if (_S_local_words <= ix)
 247       {
 248         newlimit = ix+1;
 249         try
 250           { words = new _Words[ix+1]; }
 251         catch (...)
 252           {
 253             _M_dummy = zero;  // XXX MT? Not on "normal" machines.
 254             // XXX now in basic_ios
 255             // _M_clear(_M_rdstate() | badbit);  // may throw
 256             return _M_dummy;
 257           }
 258         for (; i < _M_word_limit; i++)
 259           words[i] = _M_words[i];
 260         if (_M_words && _M_words != _M_word_array)
 261           delete [] _M_words;
 262       }
 263
 264     do { words[i] = zero; } while (++i < newlimit);
 265     _M_words = words;
 266     _M_word_limit = newlimit;
 267     return words[ix];
 268   }
 269
 270   // Called only by basic_ios<>::init.
 271   void
 272   ios_base::_M_init()
 273   {
 274     // NB: May be called more than once
 275     _M_precision = 6;
 276     _M_width = 0;
 277     _M_flags = skipws | dec;
 278     _M_callbacks = 0;
 279     _M_words = 0;
 280     _M_word_limit = 0;
 281     _M_ios_locale = locale();
 282     // No init needed for _M_word_array or _M_dummy.
 283   }
 284
 285   // 27.4.2.3  ios_base locale functions
 286   locale
 287   ios_base::imbue(const locale& __loc)
 288   {
 289     locale __old = _M_ios_locale;
 290     _M_ios_locale = __loc;
 291     _M_call_callbacks(imbue_event);
 292     return __old;
 293   }
 294
 295   ios_base::ios_base()
 296   {
 297     // Do nothing: basic_ios::init() does it.
 298     // NB: _M_callbacks and _M_words must be zero for non-initialized
 299     // ios_base to go through ~ios_base gracefully.
 300     _M_callbacks = 0;
 301     _M_words = 0;
 302   }
 303
 304   // 27.4.2.7  ios_base constructors/destructors
 305   ios_base::~ios_base()
 306   {
 307     _M_call_callbacks(erase_event);
 308     _M_dispose_callbacks();
 309     if (_M_words && _M_words != _M_word_array)
 310       delete [] _M_words;
 311   }
 312
 313   void
 314   ios_base::register_callback(event_callback __fn, int __index)
 315   { _M_callbacks = new _Callback_list(__fn, __index, _M_callbacks); }
 316
 317   void
 318   ios_base::_M_call_callbacks(event __e) throw()
 319   {
 320     _Callback_list* __p = _M_callbacks;
 321     while (__p)
 322       {
 323         try
 324           { (*__p->_M_fn) (__e, *this, __p->_M_index); }
 325         catch (...)
 326           { }
 327         __p = __p->_M_next;
 328       }
 329   }
 330
 331   void
 332   ios_base::_M_dispose_callbacks(void)
 333   {
 334     _Callback_list* __p = _M_callbacks;
 335     while (__p && __p->_M_remove_reference() == 0)
 336       {
 337         _Callback_list* __next = __p->_M_next;
 338         delete __p;
 339         __p = __next;
 340       }
 341     _M_callbacks = 0;
 342   }
 343
 344   bool
 345   ios_base::sync_with_stdio(bool __sync)
 346   {
 347 #ifdef _GLIBCPP_RESOLVE_LIB_DEFECTS
 348     // 49.  Underspecification of ios_base::sync_with_stdio
 349     bool __ret = ios_base::Init::_S_synced_with_stdio;
 350 #endif
 351
 352     // Turn off sync with C FILE* for cin, cout, cerr, clog iff
 353     // currently synchronized.
 354     if (!__sync && __ret)
 355       {
 356         ios_base::Init::_S_synced_with_stdio = false;
 357         ios_base::Init::_S_ios_destroy();
 358         ios_base::Init::_S_ios_create(ios_base::Init::_S_synced_with_stdio);
 359       }
 360     return __ret;
 361   }
 362 }  // namespace std
 363