Chris@16: // (C) Copyright 2008 CodeRage, LLC (turkanis at coderage dot com)
Chris@16: // (C) Copyright 2004-2007 Jonathan Turkanis
Chris@16: // Distributed under the Boost Software License, Version 1.0. (See accompanying
Chris@16: // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt.)
Chris@16: 
Chris@16: // See http://www.boost.org/libs/iostreams for documentation.
Chris@16: 
Chris@16: // Inspired by Daryle Walker's nullbuf from his More I/O submission.
Chris@16: 
Chris@16: #ifndef BOOST_IOSTREAMS_NULL_HPP_INCLUDED
Chris@16: #define BOOST_IOSTREAMS_NULL_HPP_INCLUDED
Chris@16: 
Chris@16: #if defined(_MSC_VER) && (_MSC_VER >= 1020)
Chris@16: # pragma once
Chris@16: #endif
Chris@16: 
Chris@16: #include <boost/iostreams/categories.hpp>
Chris@16: #include <boost/iostreams/detail/ios.hpp> // openmode, streamsize.
Chris@16: #include <boost/iostreams/positioning.hpp>
Chris@16: 
Chris@16: namespace boost { namespace iostreams {
Chris@16: 
Chris@16: template<typename Ch, typename Mode>
Chris@16: class basic_null_device {
Chris@16: public:
Chris@16:     typedef Ch char_type;
Chris@16:     struct category
Chris@16:         : public Mode,
Chris@16:           public device_tag,
Chris@16:           public closable_tag
Chris@16:         { };
Chris@16:     std::streamsize read(Ch*, std::streamsize) { return 0; }
Chris@16:     std::streamsize write(const Ch*, std::streamsize n) { return n; }
Chris@16:     std::streampos seek( stream_offset, BOOST_IOS::seekdir,
Chris@16:                          BOOST_IOS::openmode = 
Chris@16:                              BOOST_IOS::in | BOOST_IOS::out ) 
Chris@16:     { return -1; }
Chris@16:     void close() { }
Chris@16:     void close(BOOST_IOS::openmode) { }
Chris@16: };
Chris@16: 
Chris@16: template<typename Ch>
Chris@16: struct basic_null_source : private basic_null_device<Ch, input> {
Chris@16:     typedef Ch          char_type;
Chris@16:     typedef source_tag  category;
Chris@16:     using basic_null_device<Ch, input>::read;
Chris@16:     using basic_null_device<Ch, input>::close;
Chris@16: };
Chris@16: 
Chris@16: typedef basic_null_source<char>     null_source;
Chris@16: typedef basic_null_source<wchar_t>  wnull_source;
Chris@16: 
Chris@16: template<typename Ch>
Chris@16: struct basic_null_sink : private basic_null_device<Ch, output> {
Chris@16:     typedef Ch        char_type;
Chris@16:     typedef sink_tag  category;
Chris@16:     using basic_null_device<Ch, output>::write;
Chris@16:     using basic_null_device<Ch, output>::close;
Chris@16: };
Chris@16: 
Chris@16: typedef basic_null_sink<char>     null_sink;
Chris@16: typedef basic_null_sink<wchar_t>  wnull_sink;
Chris@16: 
Chris@16: } } // End namespaces iostreams, boost.
Chris@16: 
Chris@16: #endif // #ifndef BOOST_IOSTREAMS_NULL_HPP_INCLUDED