469 lines
15 KiB
C++
469 lines
15 KiB
C++
// Iostreams base classes -*- C++ -*-
|
|
|
|
// Copyright (C) 1997, 1998, 1999, 2001, 2002, 2003, 2004, 2005
|
|
// Free Software Foundation, Inc.
|
|
//
|
|
// This file is part of the GNU ISO C++ Library. This library is free
|
|
// software; you can redistribute it and/or modify it under the
|
|
// terms of the GNU General Public License as published by the
|
|
// Free Software Foundation; either version 2, or (at your option)
|
|
// any later version.
|
|
|
|
// This library is distributed in the hope that it will be useful,
|
|
// but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
// GNU General Public License for more details.
|
|
|
|
// You should have received a copy of the GNU General Public License along
|
|
// with this library; see the file COPYING. If not, write to the Free
|
|
// Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
|
|
// USA.
|
|
|
|
// As a special exception, you may use this file as part of a free software
|
|
// library without restriction. Specifically, if other files instantiate
|
|
// templates or use macros or inline functions from this file, or you compile
|
|
// this file and link it with other files to produce an executable, this
|
|
// file does not by itself cause the resulting executable to be covered by
|
|
// the GNU General Public License. This exception does not however
|
|
// invalidate any other reasons why the executable file might be covered by
|
|
// the GNU General Public License.
|
|
|
|
/** @file basic_ios.h
|
|
* This is an internal header file, included by other library headers.
|
|
* You should not attempt to use it directly.
|
|
*/
|
|
|
|
#ifndef _BASIC_IOS_H
|
|
#define _BASIC_IOS_H 1
|
|
|
|
#pragma GCC system_header
|
|
|
|
#include <bits/streambuf_iterator.h>
|
|
#include <bits/localefwd.h>
|
|
#include <bits/locale_classes.h>
|
|
#include <bits/locale_facets.h>
|
|
|
|
_GLIBCXX_BEGIN_NAMESPACE(std)
|
|
|
|
// 27.4.5 Template class basic_ios
|
|
/**
|
|
* @brief Virtual base class for all stream classes.
|
|
*
|
|
* Most of the member functions called dispatched on stream objects
|
|
* (e.g., @c std::cout.foo(bar);) are consolidated in this class.
|
|
*/
|
|
template<typename _CharT, typename _Traits>
|
|
class basic_ios : public ios_base
|
|
{
|
|
public:
|
|
//@{
|
|
/**
|
|
* These are standard types. They permit a standardized way of
|
|
* referring to names of (or names dependant on) the template
|
|
* parameters, which are specific to the implementation.
|
|
*/
|
|
typedef _CharT char_type;
|
|
typedef typename _Traits::int_type int_type;
|
|
typedef typename _Traits::pos_type pos_type;
|
|
typedef typename _Traits::off_type off_type;
|
|
typedef _Traits traits_type;
|
|
//@}
|
|
|
|
//@{
|
|
/**
|
|
* @if maint
|
|
* These are non-standard types.
|
|
* @endif
|
|
*/
|
|
typedef ctype<_CharT> __ctype_type;
|
|
typedef num_put<_CharT, ostreambuf_iterator<_CharT, _Traits> >
|
|
__num_put_type;
|
|
typedef num_get<_CharT, istreambuf_iterator<_CharT, _Traits> >
|
|
__num_get_type;
|
|
//@}
|
|
|
|
// Data members:
|
|
protected:
|
|
basic_ostream<_CharT, _Traits>* _M_tie;
|
|
mutable char_type _M_fill;
|
|
mutable bool _M_fill_init;
|
|
basic_streambuf<_CharT, _Traits>* _M_streambuf;
|
|
|
|
// Cached use_facet<ctype>, which is based on the current locale info.
|
|
const __ctype_type* _M_ctype;
|
|
// For ostream.
|
|
const __num_put_type* _M_num_put;
|
|
// For istream.
|
|
const __num_get_type* _M_num_get;
|
|
|
|
public:
|
|
//@{
|
|
/**
|
|
* @brief The quick-and-easy status check.
|
|
*
|
|
* This allows you to write constructs such as
|
|
* "if (!a_stream) ..." and "while (a_stream) ..."
|
|
*/
|
|
operator void*() const
|
|
{ return this->fail() ? 0 : const_cast<basic_ios*>(this); }
|
|
|
|
bool
|
|
operator!() const
|
|
{ return this->fail(); }
|
|
//@}
|
|
|
|
/**
|
|
* @brief Returns the error state of the stream buffer.
|
|
* @return A bit pattern (well, isn't everything?)
|
|
*
|
|
* See std::ios_base::iostate for the possible bit values. Most
|
|
* users will call one of the interpreting wrappers, e.g., good().
|
|
*/
|
|
iostate
|
|
rdstate() const
|
|
{ return _M_streambuf_state; }
|
|
|
|
/**
|
|
* @brief [Re]sets the error state.
|
|
* @param state The new state flag(s) to set.
|
|
*
|
|
* See std::ios_base::iostate for the possible bit values. Most
|
|
* users will not need to pass an argument.
|
|
*/
|
|
void
|
|
clear(iostate __state = goodbit);
|
|
|
|
/**
|
|
* @brief Sets additional flags in the error state.
|
|
* @param state The additional state flag(s) to set.
|
|
*
|
|
* See std::ios_base::iostate for the possible bit values.
|
|
*/
|
|
void
|
|
setstate(iostate __state)
|
|
{ this->clear(this->rdstate() | __state); }
|
|
|
|
// Flip the internal state on for the proper state bits, then re
|
|
// throws the propagated exception if bit also set in
|
|
// exceptions().
|
|
void
|
|
_M_setstate(iostate __state)
|
|
{
|
|
// 27.6.1.2.1 Common requirements.
|
|
// Turn this on without causing an ios::failure to be thrown.
|
|
_M_streambuf_state |= __state;
|
|
if (this->exceptions() & __state)
|
|
__throw_exception_again;
|
|
}
|
|
|
|
/**
|
|
* @brief Fast error checking.
|
|
* @return True if no error flags are set.
|
|
*
|
|
* A wrapper around rdstate.
|
|
*/
|
|
bool
|
|
good() const
|
|
{ return this->rdstate() == 0; }
|
|
|
|
/**
|
|
* @brief Fast error checking.
|
|
* @return True if the eofbit is set.
|
|
*
|
|
* Note that other iostate flags may also be set.
|
|
*/
|
|
bool
|
|
eof() const
|
|
{ return (this->rdstate() & eofbit) != 0; }
|
|
|
|
/**
|
|
* @brief Fast error checking.
|
|
* @return True if either the badbit or the failbit is set.
|
|
*
|
|
* Checking the badbit in fail() is historical practice.
|
|
* Note that other iostate flags may also be set.
|
|
*/
|
|
bool
|
|
fail() const
|
|
{ return (this->rdstate() & (badbit | failbit)) != 0; }
|
|
|
|
/**
|
|
* @brief Fast error checking.
|
|
* @return True if the badbit is set.
|
|
*
|
|
* Note that other iostate flags may also be set.
|
|
*/
|
|
bool
|
|
bad() const
|
|
{ return (this->rdstate() & badbit) != 0; }
|
|
|
|
/**
|
|
* @brief Throwing exceptions on errors.
|
|
* @return The current exceptions mask.
|
|
*
|
|
* This changes nothing in the stream. See the one-argument version
|
|
* of exceptions(iostate) for the meaning of the return value.
|
|
*/
|
|
iostate
|
|
exceptions() const
|
|
{ return _M_exception; }
|
|
|
|
/**
|
|
* @brief Throwing exceptions on errors.
|
|
* @param except The new exceptions mask.
|
|
*
|
|
* By default, error flags are set silently. You can set an
|
|
* exceptions mask for each stream; if a bit in the mask becomes set
|
|
* in the error flags, then an exception of type
|
|
* std::ios_base::failure is thrown.
|
|
*
|
|
* If the error flage is already set when the exceptions mask is
|
|
* added, the exception is immediately thrown. Try running the
|
|
* following under GCC 3.1 or later:
|
|
* @code
|
|
* #include <iostream>
|
|
* #include <fstream>
|
|
* #include <exception>
|
|
*
|
|
* int main()
|
|
* {
|
|
* std::set_terminate (__gnu_cxx::__verbose_terminate_handler);
|
|
*
|
|
* std::ifstream f ("/etc/motd");
|
|
*
|
|
* std::cerr << "Setting badbit\n";
|
|
* f.setstate (std::ios_base::badbit);
|
|
*
|
|
* std::cerr << "Setting exception mask\n";
|
|
* f.exceptions (std::ios_base::badbit);
|
|
* }
|
|
* @endcode
|
|
*/
|
|
void
|
|
exceptions(iostate __except)
|
|
{
|
|
_M_exception = __except;
|
|
this->clear(_M_streambuf_state);
|
|
}
|
|
|
|
// Constructor/destructor:
|
|
/**
|
|
* @brief Constructor performs initialization.
|
|
*
|
|
* The parameter is passed by derived streams.
|
|
*/
|
|
explicit
|
|
basic_ios(basic_streambuf<_CharT, _Traits>* __sb)
|
|
: ios_base(), _M_tie(0), _M_fill(), _M_fill_init(false), _M_streambuf(0),
|
|
_M_ctype(0), _M_num_put(0), _M_num_get(0)
|
|
{ this->init(__sb); }
|
|
|
|
/**
|
|
* @brief Empty.
|
|
*
|
|
* The destructor does nothing. More specifically, it does not
|
|
* destroy the streambuf held by rdbuf().
|
|
*/
|
|
virtual
|
|
~basic_ios() { }
|
|
|
|
// Members:
|
|
/**
|
|
* @brief Fetches the current @e tied stream.
|
|
* @return A pointer to the tied stream, or NULL if the stream is
|
|
* not tied.
|
|
*
|
|
* A stream may be @e tied (or synchronized) to a second output
|
|
* stream. When this stream performs any I/O, the tied stream is
|
|
* first flushed. For example, @c std::cin is tied to @c std::cout.
|
|
*/
|
|
basic_ostream<_CharT, _Traits>*
|
|
tie() const
|
|
{ return _M_tie; }
|
|
|
|
/**
|
|
* @brief Ties this stream to an output stream.
|
|
* @param tiestr The output stream.
|
|
* @return The previously tied output stream, or NULL if the stream
|
|
* was not tied.
|
|
*
|
|
* This sets up a new tie; see tie() for more.
|
|
*/
|
|
basic_ostream<_CharT, _Traits>*
|
|
tie(basic_ostream<_CharT, _Traits>* __tiestr)
|
|
{
|
|
basic_ostream<_CharT, _Traits>* __old = _M_tie;
|
|
_M_tie = __tiestr;
|
|
return __old;
|
|
}
|
|
|
|
/**
|
|
* @brief Accessing the underlying buffer.
|
|
* @return The current stream buffer.
|
|
*
|
|
* This does not change the state of the stream.
|
|
*/
|
|
basic_streambuf<_CharT, _Traits>*
|
|
rdbuf() const
|
|
{ return _M_streambuf; }
|
|
|
|
/**
|
|
* @brief Changing the underlying buffer.
|
|
* @param sb The new stream buffer.
|
|
* @return The previous stream buffer.
|
|
*
|
|
* Associates a new buffer with the current stream, and clears the
|
|
* error state.
|
|
*
|
|
* Due to historical accidents which the LWG refuses to correct, the
|
|
* I/O library suffers from a design error: this function is hidden
|
|
* in derived classes by overrides of the zero-argument @c rdbuf(),
|
|
* which is non-virtual for hysterical raisins. As a result, you
|
|
* must use explicit qualifications to access this function via any
|
|
* derived class. For example:
|
|
*
|
|
* @code
|
|
* std::fstream foo; // or some other derived type
|
|
* std::streambuf* p = .....;
|
|
*
|
|
* foo.ios::rdbuf(p); // ios == basic_ios<char>
|
|
* @endcode
|
|
*/
|
|
basic_streambuf<_CharT, _Traits>*
|
|
rdbuf(basic_streambuf<_CharT, _Traits>* __sb);
|
|
|
|
/**
|
|
* @brief Copies fields of __rhs into this.
|
|
* @param __rhs The source values for the copies.
|
|
* @return Reference to this object.
|
|
*
|
|
* All fields of __rhs are copied into this object except that rdbuf()
|
|
* and rdstate() remain unchanged. All values in the pword and iword
|
|
* arrays are copied. Before copying, each callback is invoked with
|
|
* erase_event. After copying, each (new) callback is invoked with
|
|
* copyfmt_event. The final step is to copy exceptions().
|
|
*/
|
|
basic_ios&
|
|
copyfmt(const basic_ios& __rhs);
|
|
|
|
/**
|
|
* @brief Retreives the "empty" character.
|
|
* @return The current fill character.
|
|
*
|
|
* It defaults to a space (' ') in the current locale.
|
|
*/
|
|
char_type
|
|
fill() const
|
|
{
|
|
if (!_M_fill_init)
|
|
{
|
|
_M_fill = this->widen(' ');
|
|
_M_fill_init = true;
|
|
}
|
|
return _M_fill;
|
|
}
|
|
|
|
/**
|
|
* @brief Sets a new "empty" character.
|
|
* @param ch The new character.
|
|
* @return The previous fill character.
|
|
*
|
|
* The fill character is used to fill out space when P+ characters
|
|
* have been requested (e.g., via setw), Q characters are actually
|
|
* used, and Q<P. It defaults to a space (' ') in the current locale.
|
|
*/
|
|
char_type
|
|
fill(char_type __ch)
|
|
{
|
|
char_type __old = this->fill();
|
|
_M_fill = __ch;
|
|
return __old;
|
|
}
|
|
|
|
// Locales:
|
|
/**
|
|
* @brief Moves to a new locale.
|
|
* @param loc The new locale.
|
|
* @return The previous locale.
|
|
*
|
|
* Calls @c ios_base::imbue(loc), and if a stream buffer is associated
|
|
* with this stream, calls that buffer's @c pubimbue(loc).
|
|
*
|
|
* Additional l10n notes are at
|
|
* http://gcc.gnu.org/onlinedocs/libstdc++/22_locale/howto.html
|
|
*/
|
|
locale
|
|
imbue(const locale& __loc);
|
|
|
|
/**
|
|
* @brief Squeezes characters.
|
|
* @param c The character to narrow.
|
|
* @param dfault The character to narrow.
|
|
* @return The narrowed character.
|
|
*
|
|
* Maps a character of @c char_type to a character of @c char,
|
|
* if possible.
|
|
*
|
|
* Returns the result of
|
|
* @code
|
|
* std::use_facet<ctype<char_type> >(getloc()).narrow(c,dfault)
|
|
* @endcode
|
|
*
|
|
* Additional l10n notes are at
|
|
* http://gcc.gnu.org/onlinedocs/libstdc++/22_locale/howto.html
|
|
*/
|
|
char
|
|
narrow(char_type __c, char __dfault) const;
|
|
|
|
/**
|
|
* @brief Widens characters.
|
|
* @param c The character to widen.
|
|
* @return The widened character.
|
|
*
|
|
* Maps a character of @c char to a character of @c char_type.
|
|
*
|
|
* Returns the result of
|
|
* @code
|
|
* std::use_facet<ctype<char_type> >(getloc()).widen(c)
|
|
* @endcode
|
|
*
|
|
* Additional l10n notes are at
|
|
* http://gcc.gnu.org/onlinedocs/libstdc++/22_locale/howto.html
|
|
*/
|
|
char_type
|
|
widen(char __c) const;
|
|
|
|
protected:
|
|
// 27.4.5.1 basic_ios constructors
|
|
/**
|
|
* @brief Empty.
|
|
*
|
|
* The default constructor does nothing and is not normally
|
|
* accessible to users.
|
|
*/
|
|
basic_ios()
|
|
: ios_base(), _M_tie(0), _M_fill(char_type()), _M_fill_init(false),
|
|
_M_streambuf(0), _M_ctype(0), _M_num_put(0), _M_num_get(0)
|
|
{ }
|
|
|
|
/**
|
|
* @brief All setup is performed here.
|
|
*
|
|
* This is called from the public constructor. It is not virtual and
|
|
* cannot be redefined.
|
|
*/
|
|
void
|
|
init(basic_streambuf<_CharT, _Traits>* __sb);
|
|
|
|
void
|
|
_M_cache_locale(const locale& __loc);
|
|
};
|
|
|
|
_GLIBCXX_END_NAMESPACE
|
|
|
|
#ifndef _GLIBCXX_EXPORT_TEMPLATE
|
|
#include <bits/basic_ios.tcc>
|
|
#endif
|
|
|
|
#endif /* _BASIC_IOS_H */
|