1 | // (C) Copyright 2008 CodeRage, LLC (turkanis at coderage dot com) |
2 | // (C) Copyright 2004-2007 Jonathan Turkanis |
3 | // Distributed under the Boost Software License, Version 1.0. (See accompanying |
4 | // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt.) |
5 | |
6 | // See http://www.boost.org/libs/iostreams for documentation. |
7 | |
8 | // Inspired by Daryle Walker's nullbuf from his More I/O submission. |
9 | |
10 | #ifndef BOOST_IOSTREAMS_NULL_HPP_INCLUDED |
11 | #define BOOST_IOSTREAMS_NULL_HPP_INCLUDED |
12 | |
13 | #if defined(_MSC_VER) |
14 | # pragma once |
15 | #endif |
16 | |
17 | #include <boost/iostreams/categories.hpp> |
18 | #include <boost/iostreams/detail/ios.hpp> // openmode, streamsize. |
19 | #include <boost/iostreams/positioning.hpp> |
20 | |
21 | namespace boost { namespace iostreams { |
22 | |
23 | template<typename Ch, typename Mode> |
24 | class basic_null_device { |
25 | public: |
26 | typedef Ch char_type; |
27 | struct category |
28 | : public Mode, |
29 | public device_tag, |
30 | public closable_tag |
31 | { }; |
32 | std::streamsize read(Ch*, std::streamsize) { return -1; } |
33 | std::streamsize write(const Ch*, std::streamsize n) { return n; } |
34 | std::streampos seek( stream_offset, BOOST_IOS::seekdir, |
35 | BOOST_IOS::openmode = |
36 | BOOST_IOS::in | BOOST_IOS::out ) |
37 | { return -1; } |
38 | void close() { } |
39 | void close(BOOST_IOS::openmode) { } |
40 | }; |
41 | |
42 | template<typename Ch> |
43 | struct basic_null_source : private basic_null_device<Ch, input> { |
44 | typedef Ch char_type; |
45 | typedef source_tag category; |
46 | using basic_null_device<Ch, input>::read; |
47 | using basic_null_device<Ch, input>::close; |
48 | }; |
49 | |
50 | typedef basic_null_source<char> null_source; |
51 | typedef basic_null_source<wchar_t> wnull_source; |
52 | |
53 | template<typename Ch> |
54 | struct basic_null_sink : private basic_null_device<Ch, output> { |
55 | typedef Ch char_type; |
56 | typedef sink_tag category; |
57 | using basic_null_device<Ch, output>::write; |
58 | using basic_null_device<Ch, output>::close; |
59 | }; |
60 | |
61 | typedef basic_null_sink<char> null_sink; |
62 | typedef basic_null_sink<wchar_t> wnull_sink; |
63 | |
64 | } } // End namespaces iostreams, boost. |
65 | |
66 | #endif // #ifndef BOOST_IOSTREAMS_NULL_HPP_INCLUDED |
67 | |