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/ File descriptor layer for filebuf -*- C++ -*-
// Copyright (C) 2002 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, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
// 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 ext/stdio_filebuf.h
* This file is a GNU extension to the Standard C++ Library.
*/
#ifndef _EXT_STDIO_FILEBUF
#define _EXT_STDIO_FILEBUF
#pragma GCC system_header
#include <fstream>
namespace __gnu_cxx
{
/**
* @class stdio_filebuf ext/stdio_filebuf.h <ext/stdio_filebuf.h>
* @brief Provides a layer of compatibility for C/POSIX.
*
* 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;
protected:
// Stack-based buffer for unbuffered input.
char_type _M_unbuf[4];
public:
/**
* @param fd An open file descriptor.
* @param mode Same meaning as in a standard filebuf.
* @param del Whether to close the file on destruction.
* @param size Optimal or preferred size of internal buffer, in bytes.
*
* This constructor associates a file stream buffer with an open
* POSIX file descriptor. Iff @a del is true, then the associated
* file will be closed when the stdio_filebuf is closed/destroyed.
*/
stdio_filebuf(int __fd, std::ios_base::openmode __mode, bool __del,
int_type __size);
/**
* @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 bytes.
* 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,
int_type __size = static_cast<int_type>(BUFSIZ));
/**
* Possibly closes the external data stream, in the case of the file
* descriptor constructor and @c del @c == @c true.
*/
virtual
~stdio_filebuf();
/**
* @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 _M_file.fd(); }
};
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, bool __del,
int_type __size)
{
_M_file.sys_open(__fd, __mode, __del);
if (this->is_open())
{
_M_mode = __mode;
if (__size > 0 && __size < 4)
{
// Specify unbuffered.
_M_buf = _M_unbuf;
_M_buf_size = __size;
_M_buf_size_opt = 0;
}
else
{
_M_buf_size_opt = __size;
_M_allocate_internal_buffer();
}
_M_set_indeterminate();
}
}
template<typename _CharT, typename _Traits>
stdio_filebuf<_CharT, _Traits>::
stdio_filebuf(std::__c_file* __f, std::ios_base::openmode __mode,
int_type __size)
{
_M_file.sys_open(__f, __mode);
if (this->is_open())
{
_M_mode = __mode;
if (__size > 0 && __size < 4)
{
// Specify unbuffered.
_M_buf = _M_unbuf;
_M_buf_size = __size;
_M_buf_size_opt = 0;
}
else
{
_M_buf_size_opt = __size;
_M_allocate_internal_buffer();
}
_M_set_indeterminate();
}
}
} // namespace __gnu_cxx
#endif /* _EXT_STDIO_FILEBUF */ |
