1// File descriptor layer for filebuf -*- C++ -*-
2
3// Copyright (C) 2002, 2003, 2004, 2005, 2009 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 ext/stdio_filebuf.h
26 *  This file is a GNU extension to the Standard C++ Library.
27 */
28
29#ifndef _STDIO_FILEBUF_H
30#define _STDIO_FILEBUF_H 1
31
32#pragma GCC system_header
33
34#include <fstream>
35
36_GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
37
38  /**
39   *  @brief Provides a layer of compatibility for C/POSIX.
40   *
41   *  This GNU extension provides extensions for working with standard C
42   *  FILE*'s and POSIX file descriptors.  It must be instantiated by the
43   *  user with the type of character used in the file stream, e.g.,
44   *  stdio_filebuf<char>.
45  */
46  template<typename _CharT, typename _Traits = std::char_traits<_CharT> >
47    class stdio_filebuf : public std::basic_filebuf<_CharT, _Traits>
48    {
49    public:
50      // Types:
51      typedef _CharT				        char_type;
52      typedef _Traits				        traits_type;
53      typedef typename traits_type::int_type		int_type;
54      typedef typename traits_type::pos_type		pos_type;
55      typedef typename traits_type::off_type		off_type;
56      typedef std::size_t                               size_t;
57
58    public:
59      /**
60       * deferred initialization
61      */
62      stdio_filebuf() : std::basic_filebuf<_CharT, _Traits>() {}
63
64      /**
65       *  @param  fd  An open file descriptor.
66       *  @param  mode  Same meaning as in a standard filebuf.
67       *  @param  size  Optimal or preferred size of internal buffer, in chars.
68       *
69       *  This constructor associates a file stream buffer with an open
70       *  POSIX file descriptor. The file descriptor will be automatically
71       *  closed when the stdio_filebuf is closed/destroyed.
72      */
73      stdio_filebuf(int __fd, std::ios_base::openmode __mode,
74		    size_t __size = static_cast<size_t>(BUFSIZ));
75
76      /**
77       *  @param  f  An open @c FILE*.
78       *  @param  mode  Same meaning as in a standard filebuf.
79       *  @param  size  Optimal or preferred size of internal buffer, in chars.
80       *                Defaults to system's @c BUFSIZ.
81       *
82       *  This constructor associates a file stream buffer with an open
83       *  C @c FILE*.  The @c FILE* will not be automatically closed when the
84       *  stdio_filebuf is closed/destroyed.
85      */
86      stdio_filebuf(std::__c_file* __f, std::ios_base::openmode __mode,
87		    size_t __size = static_cast<size_t>(BUFSIZ));
88
89      /**
90       *  Closes the external data stream if the file descriptor constructor
91       *  was used.
92      */
93      virtual
94      ~stdio_filebuf();
95
96      /**
97       *  @return  The underlying file descriptor.
98       *
99       *  Once associated with an external data stream, this function can be
100       *  used to access the underlying POSIX file descriptor.  Note that
101       *  there is no way for the library to track what you do with the
102       *  descriptor, so be careful.
103      */
104      int
105      fd() { return this->_M_file.fd(); }
106
107      /**
108       *  @return  The underlying FILE*.
109       *
110       *  This function can be used to access the underlying "C" file pointer.
111       *  Note that there is no way for the library to track what you do
112       *  with the file, so be careful.
113       */
114      std::__c_file*
115      file() { return this->_M_file.file(); }
116    };
117
118  template<typename _CharT, typename _Traits>
119    stdio_filebuf<_CharT, _Traits>::~stdio_filebuf()
120    { }
121
122  template<typename _CharT, typename _Traits>
123    stdio_filebuf<_CharT, _Traits>::
124    stdio_filebuf(int __fd, std::ios_base::openmode __mode, size_t __size)
125    {
126      this->_M_file.sys_open(__fd, __mode);
127      if (this->is_open())
128	{
129	  this->_M_mode = __mode;
130	  this->_M_buf_size = __size;
131	  this->_M_allocate_internal_buffer();
132	  this->_M_reading = false;
133	  this->_M_writing = false;
134	  this->_M_set_buffer(-1);
135	}
136    }
137
138  template<typename _CharT, typename _Traits>
139    stdio_filebuf<_CharT, _Traits>::
140    stdio_filebuf(std::__c_file* __f, std::ios_base::openmode __mode,
141		  size_t __size)
142    {
143      this->_M_file.sys_open(__f, __mode);
144      if (this->is_open())
145	{
146	  this->_M_mode = __mode;
147	  this->_M_buf_size = __size;
148	  this->_M_allocate_internal_buffer();
149	  this->_M_reading = false;
150	  this->_M_writing = false;
151	  this->_M_set_buffer(-1);
152	}
153    }
154
155_GLIBCXX_END_NAMESPACE
156
157#endif
158