stdio_filebuf.h
Go to the documentation of this file.
// File descriptor layer for filebuf -*- C++ -*-
// Copyright (C) 2002-2018 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 3, 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.
// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.
// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
// <http://www.gnu.org/licenses/>.
/** @file ext/stdio_filebuf.h
* This file is a GNU extension to the Standard C++ Library.
*/
#ifndef _STDIO_FILEBUF_H
#define _STDIO_FILEBUF_H 1
#pragma GCC system_header
#include <fstream>
namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
/**
* @brief Provides a layer of compatibility for C/POSIX.
* @ingroup io
*
* This GNU extension provides extensions for working with standard C
* FILE*'s and POSIX file descriptors. It must be instantiated by the
* user with the type of character used in the file stream, e.g.,
* stdio_filebuf<char>.
*/
template<typename _CharT, typename _Traits = std::char_traits<_CharT> >
class stdio_filebuf : public std::basic_filebuf<_CharT, _Traits>
{
public:
// Types:
typedef _CharT char_type;
typedef _Traits traits_type;
typedef typename traits_type::int_type int_type;
typedef typename traits_type::pos_type pos_type;
typedef typename traits_type::off_type off_type;
typedef std::size_t size_t;
public:
/**
* deferred initialization
*/
stdio_filebuf() : std::basic_filebuf<_CharT, _Traits>() {}
/**
* @param __fd An open file descriptor.
* @param __mode Same meaning as in a standard filebuf.
* @param __size Optimal or preferred size of internal buffer,
* in chars.
*
* This constructor associates a file stream buffer with an open
* POSIX file descriptor. The file descriptor will be automatically
* closed when the stdio_filebuf is closed/destroyed.
*/
stdio_filebuf(int __fd, std::ios_base::openmode __mode,
size_t __size = static_cast<size_t>(BUFSIZ));
/**
* @param __f An open @c FILE*.
* @param __mode Same meaning as in a standard filebuf.
* @param __size Optimal or preferred size of internal buffer,
* in chars. Defaults to system's @c BUFSIZ.
*
* This constructor associates a file stream buffer with an open
* C @c FILE*. The @c FILE* will not be automatically closed when the
* stdio_filebuf is closed/destroyed.
*/
stdio_filebuf(std::__c_file* __f, std::ios_base::openmode __mode,
size_t __size = static_cast<size_t>(BUFSIZ));
/**
* Closes the external data stream if the file descriptor constructor
* was used.
*/
virtual
~stdio_filebuf();
#if __cplusplus >= 201103L
stdio_filebuf(stdio_filebuf&&) = default;
stdio_filebuf& operator=(stdio_filebuf&&) = default;
void
swap(stdio_filebuf& __fb)
{ std::basic_filebuf<_CharT, _Traits>::swap(__fb); }
#endif
/**
* @return The underlying file descriptor.
*
* Once associated with an external data stream, this function can be
* used to access the underlying POSIX file descriptor. Note that
* there is no way for the library to track what you do with the
* descriptor, so be careful.
*/
int
fd() { return this->_M_file.fd(); }
/**
* @return The underlying FILE*.
*
* This function can be used to access the underlying "C" file pointer.
* Note that there is no way for the library to track what you do
* with the file, so be careful.
*/
std::__c_file*
file() { return this->_M_file.file(); }
};
template<typename _CharT, typename _Traits>
stdio_filebuf<_CharT, _Traits>::~stdio_filebuf()
{ }
template<typename _CharT, typename _Traits>
stdio_filebuf<_CharT, _Traits>::
stdio_filebuf(int __fd, std::ios_base::openmode __mode, size_t __size)
{
this->_M_file.sys_open(__fd, __mode);
if (this->is_open())
{
this->_M_mode = __mode;
this->_M_buf_size = __size;
this->_M_allocate_internal_buffer();
this->_M_reading = false;
this->_M_writing = false;
this->_M_set_buffer(-1);
}
}
template<typename _CharT, typename _Traits>
stdio_filebuf<_CharT, _Traits>::
stdio_filebuf(std::__c_file* __f, std::ios_base::openmode __mode,
size_t __size)
{
this->_M_file.sys_open(__f, __mode);
if (this->is_open())
{
this->_M_mode = __mode;
this->_M_buf_size = __size;
this->_M_allocate_internal_buffer();
this->_M_reading = false;
this->_M_writing = false;
this->_M_set_buffer(-1);
}
}
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace
#endif
fstream
__gnu_cxx
GNU extensions for public use.
std::basic_filebuf::_M_mode
ios_base::openmode _M_mode
Place to stash in || out || in | out settings for current filebuf.
Definition: fstream:121
__gnu_cxx::stdio_filebuf::~stdio_filebuf
virtual ~stdio_filebuf()
Definition: stdio_filebuf.h:132
std::basic_filebuf::_M_buf_size
size_t _M_buf_size
Definition: fstream:143
__gnu_cxx::stdio_filebuf::fd
int fd()
Definition: stdio_filebuf.h:118
__gnu_cxx::stdio_filebuf::file
std::__c_file * file()
Definition: stdio_filebuf.h:128
__gnu_cxx::stdio_filebuf
Provides a layer of compatibility for C/POSIX.This GNU extension provides extensions for working with...
Definition: stdio_filebuf.h:50
std
ISO C++ entities toplevel namespace is std.
std::basic_filebuf::basic_filebuf
basic_filebuf()
Does not open any files.
Definition: fstream.tcc:80
std::basic_filebuf::_M_set_buffer
void _M_set_buffer(streamsize __off)
Definition: fstream:443
std::basic_filebuf::_M_reading
bool _M_reading
Definition: fstream:155
std::basic_filebuf::is_open
bool is_open() const
Returns true if the external file is open.
Definition: fstream:260
std::basic_filebuf
The actual work of input and output (for files).
Definition: fstream:80
__gnu_cxx::stdio_filebuf::stdio_filebuf
stdio_filebuf()
Definition: stdio_filebuf.h:65