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