LCOV - code coverage report
Current view: top level - usr/include/c++/4.9/bits - basic_ios.h (source / functions) Hit Total Coverage
Test: coverage.info Lines: 0 18 0.0 %
Date: 2016-12-01 18:45:36 Functions: 0 9 0.0 %

          Line data    Source code
       1             : // Iostreams base classes -*- C++ -*-
       2             : 
       3             : // Copyright (C) 1997-2014 Free Software Foundation, Inc.
       4             : //
       5             : // This file is part of the GNU ISO C++ Library.  This library is free
       6             : // software; you can redistribute it and/or modify it under the
       7             : // terms of the GNU General Public License as published by the
       8             : // Free Software Foundation; either version 3, or (at your option)
       9             : // any later version.
      10             : 
      11             : // This library is distributed in the hope that it will be useful,
      12             : // but WITHOUT ANY WARRANTY; without even the implied warranty of
      13             : // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      14             : // GNU General Public License for more details.
      15             : 
      16             : // Under Section 7 of GPL version 3, you are granted additional
      17             : // permissions described in the GCC Runtime Library Exception, version
      18             : // 3.1, as published by the Free Software Foundation.
      19             : 
      20             : // You should have received a copy of the GNU General Public License and
      21             : // a copy of the GCC Runtime Library Exception along with this program;
      22             : // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
      23             : // <http://www.gnu.org/licenses/>.
      24             : 
      25             : /** @file bits/basic_ios.h
      26             :  *  This is an internal header file, included by other library headers.
      27             :  *  Do not attempt to use it directly. @headername{ios}
      28             :  */
      29             : 
      30             : #ifndef _BASIC_IOS_H
      31             : #define _BASIC_IOS_H 1
      32             : 
      33             : #pragma GCC system_header
      34             : 
      35             : #include <bits/localefwd.h>
      36             : #include <bits/locale_classes.h>
      37             : #include <bits/locale_facets.h>
      38             : #include <bits/streambuf_iterator.h>
      39             : 
      40             : namespace std _GLIBCXX_VISIBILITY(default)
      41             : {
      42             : _GLIBCXX_BEGIN_NAMESPACE_VERSION
      43             : 
      44             :   template<typename _Facet>
      45             :     inline const _Facet&
      46           0 :     __check_facet(const _Facet* __f)
      47             :     {
      48           0 :       if (!__f)
      49           0 :         __throw_bad_cast();
      50           0 :       return *__f;
      51             :     }
      52             : 
      53             :   /**
      54             :    *  @brief Template class basic_ios, virtual base class for all
      55             :    *  stream classes. 
      56             :    *  @ingroup io
      57             :    *
      58             :    *  @tparam _CharT  Type of character stream.
      59             :    *  @tparam _Traits  Traits for character type, defaults to
      60             :    *                   char_traits<_CharT>.
      61             :    *
      62             :    *  Most of the member functions called dispatched on stream objects
      63             :    *  (e.g., @c std::cout.foo(bar);) are consolidated in this class.
      64             :   */
      65             :   template<typename _CharT, typename _Traits>
      66             :     class basic_ios : public ios_base
      67             :     {
      68             :     public:
      69             :       //@{
      70             :       /**
      71             :        *  These are standard types.  They permit a standardized way of
      72             :        *  referring to names of (or names dependent on) the template
      73             :        *  parameters, which are specific to the implementation.
      74             :       */
      75             :       typedef _CharT                                 char_type;
      76             :       typedef typename _Traits::int_type             int_type;
      77             :       typedef typename _Traits::pos_type             pos_type;
      78             :       typedef typename _Traits::off_type             off_type;
      79             :       typedef _Traits                                traits_type;
      80             :       //@}
      81             : 
      82             :       //@{
      83             :       /**
      84             :        *  These are non-standard types.
      85             :       */
      86             :       typedef ctype<_CharT>                          __ctype_type;
      87             :       typedef num_put<_CharT, ostreambuf_iterator<_CharT, _Traits> >
      88             :                                                      __num_put_type;
      89             :       typedef num_get<_CharT, istreambuf_iterator<_CharT, _Traits> >
      90             :                                                      __num_get_type;
      91             :       //@}
      92             : 
      93             :       // Data members:
      94             :     protected:
      95             :       basic_ostream<_CharT, _Traits>*                _M_tie;
      96             :       mutable char_type                              _M_fill;
      97             :       mutable bool                                   _M_fill_init;
      98             :       basic_streambuf<_CharT, _Traits>*              _M_streambuf;
      99             : 
     100             :       // Cached use_facet<ctype>, which is based on the current locale info.
     101             :       const __ctype_type*                            _M_ctype;
     102             :       // For ostream.
     103             :       const __num_put_type*                          _M_num_put;
     104             :       // For istream.
     105             :       const __num_get_type*                          _M_num_get;
     106             : 
     107             :     public:
     108             :       //@{
     109             :       /**
     110             :        *  @brief  The quick-and-easy status check.
     111             :        *
     112             :        *  This allows you to write constructs such as
     113             :        *  <code>if (!a_stream) ...</code> and <code>while (a_stream) ...</code>
     114             :       */
     115           0 :       operator void*() const
     116           0 :       { return this->fail() ? 0 : const_cast<basic_ios*>(this); }
     117             : 
     118             :       bool
     119             :       operator!() const
     120             :       { return this->fail(); }
     121             :       //@}
     122             : 
     123             :       /**
     124             :        *  @brief  Returns the error state of the stream buffer.
     125             :        *  @return  A bit pattern (well, isn't everything?)
     126             :        *
     127             :        *  See std::ios_base::iostate for the possible bit values.  Most
     128             :        *  users will call one of the interpreting wrappers, e.g., good().
     129             :       */
     130             :       iostate
     131           0 :       rdstate() const
     132           0 :       { return _M_streambuf_state; }
     133             : 
     134             :       /**
     135             :        *  @brief  [Re]sets the error state.
     136             :        *  @param  __state  The new state flag(s) to set.
     137             :        *
     138             :        *  See std::ios_base::iostate for the possible bit values.  Most
     139             :        *  users will not need to pass an argument.
     140             :       */
     141             :       void
     142             :       clear(iostate __state = goodbit);
     143             : 
     144             :       /**
     145             :        *  @brief  Sets additional flags in the error state.
     146             :        *  @param  __state  The additional state flag(s) to set.
     147             :        *
     148             :        *  See std::ios_base::iostate for the possible bit values.
     149             :       */
     150             :       void
     151           0 :       setstate(iostate __state)
     152           0 :       { this->clear(this->rdstate() | __state); }
     153             : 
     154             :       // Flip the internal state on for the proper state bits, then re
     155             :       // throws the propagated exception if bit also set in
     156             :       // exceptions().
     157             :       void
     158             :       _M_setstate(iostate __state)
     159             :       {
     160             :         // 27.6.1.2.1 Common requirements.
     161             :         // Turn this on without causing an ios::failure to be thrown.
     162             :         _M_streambuf_state |= __state;
     163             :         if (this->exceptions() & __state)
     164             :           __throw_exception_again;
     165             :       }
     166             : 
     167             :       /**
     168             :        *  @brief  Fast error checking.
     169             :        *  @return  True if no error flags are set.
     170             :        *
     171             :        *  A wrapper around rdstate.
     172             :       */
     173             :       bool
     174             :       good() const
     175             :       { return this->rdstate() == 0; }
     176             : 
     177             :       /**
     178             :        *  @brief  Fast error checking.
     179             :        *  @return  True if the eofbit is set.
     180             :        *
     181             :        *  Note that other iostate flags may also be set.
     182             :       */
     183             :       bool
     184             :       eof() const
     185             :       { return (this->rdstate() & eofbit) != 0; }
     186             : 
     187             :       /**
     188             :        *  @brief  Fast error checking.
     189             :        *  @return  True if either the badbit or the failbit is set.
     190             :        *
     191             :        *  Checking the badbit in fail() is historical practice.
     192             :        *  Note that other iostate flags may also be set.
     193             :       */
     194             :       bool
     195           0 :       fail() const
     196           0 :       { return (this->rdstate() & (badbit | failbit)) != 0; }
     197             : 
     198             :       /**
     199             :        *  @brief  Fast error checking.
     200             :        *  @return  True if the badbit is set.
     201             :        *
     202             :        *  Note that other iostate flags may also be set.
     203             :       */
     204             :       bool
     205             :       bad() const
     206             :       { return (this->rdstate() & badbit) != 0; }
     207             : 
     208             :       /**
     209             :        *  @brief  Throwing exceptions on errors.
     210             :        *  @return  The current exceptions mask.
     211             :        *
     212             :        *  This changes nothing in the stream.  See the one-argument version
     213             :        *  of exceptions(iostate) for the meaning of the return value.
     214             :       */
     215             :       iostate
     216             :       exceptions() const
     217             :       { return _M_exception; }
     218             : 
     219             :       /**
     220             :        *  @brief  Throwing exceptions on errors.
     221             :        *  @param  __except  The new exceptions mask.
     222             :        *
     223             :        *  By default, error flags are set silently.  You can set an
     224             :        *  exceptions mask for each stream; if a bit in the mask becomes set
     225             :        *  in the error flags, then an exception of type
     226             :        *  std::ios_base::failure is thrown.
     227             :        *
     228             :        *  If the error flag is already set when the exceptions mask is
     229             :        *  added, the exception is immediately thrown.  Try running the
     230             :        *  following under GCC 3.1 or later:
     231             :        *  @code
     232             :        *  #include <iostream>
     233             :        *  #include <fstream>
     234             :        *  #include <exception>
     235             :        *
     236             :        *  int main()
     237             :        *  {
     238             :        *      std::set_terminate (__gnu_cxx::__verbose_terminate_handler);
     239             :        *
     240             :        *      std::ifstream f ("/etc/motd");
     241             :        *
     242             :        *      std::cerr << "Setting badbit\n";
     243             :        *      f.setstate (std::ios_base::badbit);
     244             :        *
     245             :        *      std::cerr << "Setting exception mask\n";
     246             :        *      f.exceptions (std::ios_base::badbit);
     247             :        *  }
     248             :        *  @endcode
     249             :       */
     250             :       void
     251             :       exceptions(iostate __except)
     252             :       {
     253             :         _M_exception = __except;
     254             :         this->clear(_M_streambuf_state);
     255             :       }
     256             : 
     257             :       // Constructor/destructor:
     258             :       /**
     259             :        *  @brief  Constructor performs initialization.
     260             :        *
     261             :        *  The parameter is passed by derived streams.
     262             :       */
     263             :       explicit
     264             :       basic_ios(basic_streambuf<_CharT, _Traits>* __sb)
     265             :       : ios_base(), _M_tie(0), _M_fill(), _M_fill_init(false), _M_streambuf(0),
     266             :         _M_ctype(0), _M_num_put(0), _M_num_get(0)
     267             :       { this->init(__sb); }
     268             : 
     269             :       /**
     270             :        *  @brief  Empty.
     271             :        *
     272             :        *  The destructor does nothing.  More specifically, it does not
     273             :        *  destroy the streambuf held by rdbuf().
     274             :       */
     275             :       virtual
     276           0 :       ~basic_ios() { }
     277             : 
     278             :       // Members:
     279             :       /**
     280             :        *  @brief  Fetches the current @e tied stream.
     281             :        *  @return  A pointer to the tied stream, or NULL if the stream is
     282             :        *           not tied.
     283             :        *
     284             :        *  A stream may be @e tied (or synchronized) to a second output
     285             :        *  stream.  When this stream performs any I/O, the tied stream is
     286             :        *  first flushed.  For example, @c std::cin is tied to @c std::cout.
     287             :       */
     288             :       basic_ostream<_CharT, _Traits>*
     289             :       tie() const
     290             :       { return _M_tie; }
     291             : 
     292             :       /**
     293             :        *  @brief  Ties this stream to an output stream.
     294             :        *  @param  __tiestr  The output stream.
     295             :        *  @return  The previously tied output stream, or NULL if the stream
     296             :        *           was not tied.
     297             :        *
     298             :        *  This sets up a new tie; see tie() for more.
     299             :       */
     300             :       basic_ostream<_CharT, _Traits>*
     301             :       tie(basic_ostream<_CharT, _Traits>* __tiestr)
     302             :       {
     303             :         basic_ostream<_CharT, _Traits>* __old = _M_tie;
     304             :         _M_tie = __tiestr;
     305             :         return __old;
     306             :       }
     307             : 
     308             :       /**
     309             :        *  @brief  Accessing the underlying buffer.
     310             :        *  @return  The current stream buffer.
     311             :        *
     312             :        *  This does not change the state of the stream.
     313             :       */
     314             :       basic_streambuf<_CharT, _Traits>*
     315             :       rdbuf() const
     316             :       { return _M_streambuf; }
     317             : 
     318             :       /**
     319             :        *  @brief  Changing the underlying buffer.
     320             :        *  @param  __sb  The new stream buffer.
     321             :        *  @return  The previous stream buffer.
     322             :        *
     323             :        *  Associates a new buffer with the current stream, and clears the
     324             :        *  error state.
     325             :        *
     326             :        *  Due to historical accidents which the LWG refuses to correct, the
     327             :        *  I/O library suffers from a design error:  this function is hidden
     328             :        *  in derived classes by overrides of the zero-argument @c rdbuf(),
     329             :        *  which is non-virtual for hysterical raisins.  As a result, you
     330             :        *  must use explicit qualifications to access this function via any
     331             :        *  derived class.  For example:
     332             :        *
     333             :        *  @code
     334             :        *  std::fstream     foo;         // or some other derived type
     335             :        *  std::streambuf*  p = .....;
     336             :        *
     337             :        *  foo.ios::rdbuf(p);            // ios == basic_ios<char>
     338             :        *  @endcode
     339             :       */
     340             :       basic_streambuf<_CharT, _Traits>*
     341             :       rdbuf(basic_streambuf<_CharT, _Traits>* __sb);
     342             : 
     343             :       /**
     344             :        *  @brief  Copies fields of __rhs into this.
     345             :        *  @param  __rhs  The source values for the copies.
     346             :        *  @return  Reference to this object.
     347             :        *
     348             :        *  All fields of __rhs are copied into this object except that rdbuf()
     349             :        *  and rdstate() remain unchanged.  All values in the pword and iword
     350             :        *  arrays are copied.  Before copying, each callback is invoked with
     351             :        *  erase_event.  After copying, each (new) callback is invoked with
     352             :        *  copyfmt_event.  The final step is to copy exceptions().
     353             :       */
     354             :       basic_ios&
     355             :       copyfmt(const basic_ios& __rhs);
     356             : 
     357             :       /**
     358             :        *  @brief  Retrieves the @a empty character.
     359             :        *  @return  The current fill character.
     360             :        *
     361             :        *  It defaults to a space (' ') in the current locale.
     362             :       */
     363             :       char_type
     364             :       fill() const
     365             :       {
     366             :         if (!_M_fill_init)
     367             :           {
     368             :             _M_fill = this->widen(' ');
     369             :             _M_fill_init = true;
     370             :           }
     371             :         return _M_fill;
     372             :       }
     373             : 
     374             :       /**
     375             :        *  @brief  Sets a new @a empty character.
     376             :        *  @param  __ch  The new character.
     377             :        *  @return  The previous fill character.
     378             :        *
     379             :        *  The fill character is used to fill out space when P+ characters
     380             :        *  have been requested (e.g., via setw), Q characters are actually
     381             :        *  used, and Q<P.  It defaults to a space (' ') in the current locale.
     382             :       */
     383             :       char_type
     384             :       fill(char_type __ch)
     385             :       {
     386             :         char_type __old = this->fill();
     387             :         _M_fill = __ch;
     388             :         return __old;
     389             :       }
     390             : 
     391             :       // Locales:
     392             :       /**
     393             :        *  @brief  Moves to a new locale.
     394             :        *  @param  __loc  The new locale.
     395             :        *  @return  The previous locale.
     396             :        *
     397             :        *  Calls @c ios_base::imbue(loc), and if a stream buffer is associated
     398             :        *  with this stream, calls that buffer's @c pubimbue(loc).
     399             :        *
     400             :        *  Additional l10n notes are at
     401             :        *  http://gcc.gnu.org/onlinedocs/libstdc++/manual/localization.html
     402             :       */
     403             :       locale
     404             :       imbue(const locale& __loc);
     405             : 
     406             :       /**
     407             :        *  @brief  Squeezes characters.
     408             :        *  @param  __c  The character to narrow.
     409             :        *  @param  __dfault  The character to narrow.
     410             :        *  @return  The narrowed character.
     411             :        *
     412             :        *  Maps a character of @c char_type to a character of @c char,
     413             :        *  if possible.
     414             :        *
     415             :        *  Returns the result of
     416             :        *  @code
     417             :        *    std::use_facet<ctype<char_type> >(getloc()).narrow(c,dfault)
     418             :        *  @endcode
     419             :        *
     420             :        *  Additional l10n notes are at
     421             :        *  http://gcc.gnu.org/onlinedocs/libstdc++/manual/localization.html
     422             :       */
     423             :       char
     424             :       narrow(char_type __c, char __dfault) const
     425             :       { return __check_facet(_M_ctype).narrow(__c, __dfault); }
     426             : 
     427             :       /**
     428             :        *  @brief  Widens characters.
     429             :        *  @param  __c  The character to widen.
     430             :        *  @return  The widened character.
     431             :        *
     432             :        *  Maps a character of @c char to a character of @c char_type.
     433             :        *
     434             :        *  Returns the result of
     435             :        *  @code
     436             :        *    std::use_facet<ctype<char_type> >(getloc()).widen(c)
     437             :        *  @endcode
     438             :        *
     439             :        *  Additional l10n notes are at
     440             :        *  http://gcc.gnu.org/onlinedocs/libstdc++/manual/localization.html
     441             :       */
     442             :       char_type
     443           0 :       widen(char __c) const
     444           0 :       { return __check_facet(_M_ctype).widen(__c); }
     445             : 
     446             :     protected:
     447             :       // 27.4.5.1  basic_ios constructors
     448             :       /**
     449             :        *  @brief  Empty.
     450             :        *
     451             :        *  The default constructor does nothing and is not normally
     452             :        *  accessible to users.
     453             :       */
     454           0 :       basic_ios()
     455             :       : ios_base(), _M_tie(0), _M_fill(char_type()), _M_fill_init(false), 
     456           0 :         _M_streambuf(0), _M_ctype(0), _M_num_put(0), _M_num_get(0)
     457           0 :       { }
     458             : 
     459             :       /**
     460             :        *  @brief  All setup is performed here.
     461             :        *
     462             :        *  This is called from the public constructor.  It is not virtual and
     463             :        *  cannot be redefined.
     464             :       */
     465             :       void
     466             :       init(basic_streambuf<_CharT, _Traits>* __sb);
     467             : 
     468             :       void
     469             :       _M_cache_locale(const locale& __loc);
     470             :     };
     471             : 
     472             : _GLIBCXX_END_NAMESPACE_VERSION
     473             : } // namespace
     474             : 
     475             : #include <bits/basic_ios.tcc>
     476             : 
     477             : #endif /* _BASIC_IOS_H */

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