1// File descriptor layer for filebuf -*- C++ -*-
2
3// Copyright (C) 2002, 2003, 2004, 2005 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 2, 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// You should have received a copy of the GNU General Public License along
17// with this library; see the file COPYING.  If not, write to the Free
18// Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
19// USA.
20
21// As a special exception, you may use this file as part of a free software
22// library without restriction.  Specifically, if other files instantiate
23// templates or use macros or inline functions from this file, or you compile
24// this file and link it with other files to produce an executable, this
25// file does not by itself cause the resulting executable to be covered by
26// the GNU General Public License.  This exception does not however
27// invalidate any other reasons why the executable file might be covered by
28// the GNU General Public License.
29
30/** @file ext/stdio_filebuf.h
31 *  This file is a GNU extension to the Standard C++ Library.
32 */
33
34#ifndef _STDIO_FILEBUF_H
35#define _STDIO_FILEBUF_H 1
36
37#pragma GCC system_header
38
39#include <fstream>
40
41_GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
42
43  /**
44   *  @brief Provides a layer of compatibility for C/POSIX.
45   *
46   *  This GNU extension provides extensions for working with standard C
47   *  FILE*'s and POSIX file descriptors.  It must be instantiated by the
48   *  user with the type of character used in the file stream, e.g.,
49   *  stdio_filebuf<char>.
50  */
51  template<typename _CharT, typename _Traits = std::char_traits<_CharT> >
52    class stdio_filebuf : public std::basic_filebuf<_CharT, _Traits>
53    {
54    public:
55      // Types:
56      typedef _CharT				        char_type;
57      typedef _Traits				        traits_type;
58      typedef typename traits_type::int_type		int_type;
59      typedef typename traits_type::pos_type		pos_type;
60      typedef typename traits_type::off_type		off_type;
61      typedef std::size_t                               size_t;
62
63    public:
64      /**
65       * deferred initialization
66      */
67      stdio_filebuf() : std::basic_filebuf<_CharT, _Traits>() {}
68
69      /**
70       *  @param  fd  An open file descriptor.
71       *  @param  mode  Same meaning as in a standard filebuf.
72       *  @param  size  Optimal or preferred size of internal buffer, 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, in chars.
85       *                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
161
162#endif
163