1// File descriptor layer for filebuf -*- C++ -*-
2
3// Copyright (C) 2002-2013 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
36namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
37{
38_GLIBCXX_BEGIN_NAMESPACE_VERSION
39
40  /**
41   *  @brief Provides a layer of compatibility for C/POSIX.
42   *  @ingroup io
43   *
44   *  This GNU extension provides extensions for working with standard C
45   *  FILE*'s and POSIX file descriptors.  It must be instantiated by the
46   *  user with the type of character used in the file stream, e.g.,
47   *  stdio_filebuf<char>.
48  */
49  template<typename _CharT, typename _Traits = std::char_traits<_CharT> >
50    class stdio_filebuf : public std::basic_filebuf<_CharT, _Traits>
51    {
52    public:
53      // Types:
54      typedef _CharT				        char_type;
55      typedef _Traits				        traits_type;
56      typedef typename traits_type::int_type		int_type;
57      typedef typename traits_type::pos_type		pos_type;
58      typedef typename traits_type::off_type		off_type;
59      typedef std::size_t                               size_t;
60
61    public:
62      /**
63       * deferred initialization
64      */
65      stdio_filebuf() : std::basic_filebuf<_CharT, _Traits>() {}
66
67      /**
68       *  @param  __fd  An open file descriptor.
69       *  @param  __mode  Same meaning as in a standard filebuf.
70       *  @param  __size Optimal or preferred size of internal buffer,
71       *                 in chars.
72       *
73       *  This constructor associates a file stream buffer with an open
74       *  POSIX file descriptor. The file descriptor will be automatically
75       *  closed when the stdio_filebuf is closed/destroyed.
76      */
77      stdio_filebuf(int __fd, std::ios_base::openmode __mode,
78		    size_t __size = static_cast<size_t>(BUFSIZ));
79
80      /**
81       *  @param  __f  An open @c FILE*.
82       *  @param  __mode  Same meaning as in a standard filebuf.
83       *  @param  __size Optimal or preferred size of internal buffer,
84       *                 in chars.  Defaults to system's @c BUFSIZ.
85       *
86       *  This constructor associates a file stream buffer with an open
87       *  C @c FILE*.  The @c FILE* will not be automatically closed when the
88       *  stdio_filebuf is closed/destroyed.
89      */
90      stdio_filebuf(std::__c_file* __f, std::ios_base::openmode __mode,
91		    size_t __size = static_cast<size_t>(BUFSIZ));
92
93      /**
94       *  Closes the external data stream if the file descriptor constructor
95       *  was used.
96      */
97      virtual
98      ~stdio_filebuf();
99
100      /**
101       *  @return  The underlying file descriptor.
102       *
103       *  Once associated with an external data stream, this function can be
104       *  used to access the underlying POSIX file descriptor.  Note that
105       *  there is no way for the library to track what you do with the
106       *  descriptor, so be careful.
107      */
108      int
109      fd() { return this->_M_file.fd(); }
110
111      /**
112       *  @return  The underlying FILE*.
113       *
114       *  This function can be used to access the underlying "C" file pointer.
115       *  Note that there is no way for the library to track what you do
116       *  with the file, so be careful.
117       */
118      std::__c_file*
119      file() { return this->_M_file.file(); }
120    };
121
122  template<typename _CharT, typename _Traits>
123    stdio_filebuf<_CharT, _Traits>::~stdio_filebuf()
124    { }
125
126  template<typename _CharT, typename _Traits>
127    stdio_filebuf<_CharT, _Traits>::
128    stdio_filebuf(int __fd, std::ios_base::openmode __mode, size_t __size)
129    {
130      this->_M_file.sys_open(__fd, __mode);
131      if (this->is_open())
132	{
133	  this->_M_mode = __mode;
134	  this->_M_buf_size = __size;
135	  this->_M_allocate_internal_buffer();
136	  this->_M_reading = false;
137	  this->_M_writing = false;
138	  this->_M_set_buffer(-1);
139	}
140    }
141
142  template<typename _CharT, typename _Traits>
143    stdio_filebuf<_CharT, _Traits>::
144    stdio_filebuf(std::__c_file* __f, std::ios_base::openmode __mode,
145		  size_t __size)
146    {
147      this->_M_file.sys_open(__f, __mode);
148      if (this->is_open())
149	{
150	  this->_M_mode = __mode;
151	  this->_M_buf_size = __size;
152	  this->_M_allocate_internal_buffer();
153	  this->_M_reading = false;
154	  this->_M_writing = false;
155	  this->_M_set_buffer(-1);
156	}
157    }
158
159_GLIBCXX_END_NAMESPACE_VERSION
160} // namespace
161
162#endif
163