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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 0; } | |
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 |