1// File descriptor layer for filebuf -*- C++ -*-
2
3// Copyright (C) 2002, 2003, 2004, 2005, 2009, 2010
4// Free Software Foundation, Inc.
5//
6// This file is part of the GNU ISO C++ Library.  This library is free
7// software; you can redistribute it and/or modify it under the
8// terms of the GNU General Public License as published by the
9// Free Software Foundation; either version 3, or (at your option)
10// any later version.
11
12// This library is distributed in the hope that it will be useful,
13// but WITHOUT ANY WARRANTY; without even the implied warranty of
14// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15// GNU General Public License for more details.
16
17// Under Section 7 of GPL version 3, you are granted additional
18// permissions described in the GCC Runtime Library Exception, version
19// 3.1, as published by the Free Software Foundation.
20
21// You should have received a copy of the GNU General Public License and
22// a copy of the GCC Runtime Library Exception along with this program;
23// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
24// <http://www.gnu.org/licenses/>.
25
26/** @file ext/stdio_filebuf.h
27 *  This file is a GNU extension to the Standard C++ Library.
28 */
29
30#ifndef _STDIO_FILEBUF_H
31#define _STDIO_FILEBUF_H 1
32
33#pragma GCC system_header
34
35#include <fstream>
36
37namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
38{
39_GLIBCXX_BEGIN_NAMESPACE_VERSION
40
41  /**
42   *  @brief Provides a layer of compatibility for C/POSIX.
43   *  @ingroup io
44   *
45   *  This GNU extension provides extensions for working with standard C
46   *  FILE*'s and POSIX file descriptors.  It must be instantiated by the
47   *  user with the type of character used in the file stream, e.g.,
48   *  stdio_filebuf<char>.
49  */
50  template<typename _CharT, typename _Traits = std::char_traits<_CharT> >
51    class stdio_filebuf : public std::basic_filebuf<_CharT, _Traits>
52    {
53    public:
54      // Types:
55      typedef _CharT				        char_type;
56      typedef _Traits				        traits_type;
57      typedef typename traits_type::int_type		int_type;
58      typedef typename traits_type::pos_type		pos_type;
59      typedef typename traits_type::off_type		off_type;
60      typedef std::size_t                               size_t;
61
62    public:
63      /**
64       * deferred initialization
65      */
66      stdio_filebuf() : std::basic_filebuf<_CharT, _Traits>() {}
67
68      /**
69       *  @param  __fd  An open file descriptor.
70       *  @param  __mode  Same meaning as in a standard filebuf.
71       *  @param  __size Optimal or preferred size of internal buffer,
72       *                 in chars.
73       *
74       *  This constructor associates a file stream buffer with an open
75       *  POSIX file descriptor. The file descriptor will be automatically
76       *  closed when the stdio_filebuf is closed/destroyed.
77      */
78      stdio_filebuf(int __fd, std::ios_base::openmode __mode,
79		    size_t __size = static_cast<size_t>(BUFSIZ));
80
81      /**
82       *  @param  __f  An open @c FILE*.
83       *  @param  __mode  Same meaning as in a standard filebuf.
84       *  @param  __size Optimal or preferred size of internal buffer,
85       *                 in chars.  Defaults to system's @c BUFSIZ.
86       *
87       *  This constructor associates a file stream buffer with an open
88       *  C @c FILE*.  The @c FILE* will not be automatically closed when the
89       *  stdio_filebuf is closed/destroyed.
90      */
91      stdio_filebuf(std::__c_file* __f, std::ios_base::openmode __mode,
92		    size_t __size = static_cast<size_t>(BUFSIZ));
93
94      /**
95       *  Closes the external data stream if the file descriptor constructor
96       *  was used.
97      */
98      virtual
99      ~stdio_filebuf();
100
101      /**
102       *  @return  The underlying file descriptor.
103       *
104       *  Once associated with an external data stream, this function can be
105       *  used to access the underlying POSIX file descriptor.  Note that
106       *  there is no way for the library to track what you do with the
107       *  descriptor, so be careful.
108      */
109      int
110      fd() { return this->_M_file.fd(); }
111
112      /**
113       *  @return  The underlying FILE*.
114       *
115       *  This function can be used to access the underlying "C" file pointer.
116       *  Note that there is no way for the library to track what you do
117       *  with the file, so be careful.
118       */
119      std::__c_file*
120      file() { return this->_M_file.file(); }
121    };
122
123  template<typename _CharT, typename _Traits>
124    stdio_filebuf<_CharT, _Traits>::~stdio_filebuf()
125    { }
126
127  template<typename _CharT, typename _Traits>
128    stdio_filebuf<_CharT, _Traits>::
129    stdio_filebuf(int __fd, std::ios_base::openmode __mode, size_t __size)
130    {
131      this->_M_file.sys_open(__fd, __mode);
132      if (this->is_open())
133	{
134	  this->_M_mode = __mode;
135	  this->_M_buf_size = __size;
136	  this->_M_allocate_internal_buffer();
137	  this->_M_reading = false;
138	  this->_M_writing = false;
139	  this->_M_set_buffer(-1);
140	}
141    }
142
143  template<typename _CharT, typename _Traits>
144    stdio_filebuf<_CharT, _Traits>::
145    stdio_filebuf(std::__c_file* __f, std::ios_base::openmode __mode,
146		  size_t __size)
147    {
148      this->_M_file.sys_open(__f, __mode);
149      if (this->is_open())
150	{
151	  this->_M_mode = __mode;
152	  this->_M_buf_size = __size;
153	  this->_M_allocate_internal_buffer();
154	  this->_M_reading = false;
155	  this->_M_writing = false;
156	  this->_M_set_buffer(-1);
157	}
158    }
159
160_GLIBCXX_END_NAMESPACE_VERSION
161} // namespace
162
163#endif
164