iostreams/filter/stdio.hpp

0001 // (C) Copyright 2008 CodeRage, LLC (turkanis at coderage dot com)
0002 // (C) Copyright 2005-2007 Jonathan Turkanis
0003 // Distributed under the Boost Software License, Version 1.0. (See accompanying
0004 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt.)
0005
0006 // See http://www.boost.org/libs/iostreams for documentation.
0007
0008 // Based on the work of Christopher Diggins.
0009
0010 #ifndef BOOST_IOSTREAMS_STDIO_FILTER_HPP_INCLUDED
0011 #define BOOST_IOSTREAMS_STDIO_FILTER_HPP_INCLUDED
0012
0013 #if defined(_MSC_VER)
0014 # pragma once
0015 #endif
0016
0017 #include <iostream>
0018 #include <memory>    // allocator.
0019 #include <vector>
0020 #include <boost/iostreams/detail/config/wide_streams.hpp>
0021 #include <boost/iostreams/detail/char_traits.hpp>
0022 #include <boost/iostreams/detail/ios.hpp>
0023 #include <boost/iostreams/device/array.hpp>
0024 #include <boost/iostreams/device/back_inserter.hpp>
0025 #include <boost/iostreams/filter/aggregate.hpp>
0026 #include <boost/iostreams/pipeline.hpp>
0027 #include <boost/iostreams/stream_buffer.hpp>
0028
0029 namespace boost { namespace iostreams {
0030
0031 namespace detail {
0032
0033 } // End namespace detail.
0034
0035 template<typename Ch, typename Alloc = std::allocator<Ch> >
0036 class basic_stdio_filter : public aggregate_filter<Ch, Alloc> {
0037 private:
0038     typedef aggregate_filter<Ch, Alloc>       base_type;
0039 public:
0040     typedef typename base_type::char_type    char_type;
0041     typedef typename base_type::category     category;
0042     typedef typename base_type::vector_type  vector_type;
0043 private:
0044     static std::istream& standard_input(char*) { return std::cin; }
0045     static std::ostream& standard_output(char*) { return std::cout; }
0046 #ifndef BOOST_IOSTREAMS_NO_WIDE_STREAMS
0047     static std::wistream& standard_input(wchar_t*) { return std::wcin; }
0048     static std::wostream& standard_output(wchar_t*) { return std::wcout; }
0049 #endif // BOOST_IOSTREAMS_NO_WIDE_STREAMS
0050
0051     struct scoped_redirector { // Thanks to Maxim Egorushkin.
0052         typedef BOOST_IOSTREAMS_CHAR_TRAITS(Ch)                  traits_type;
0053         typedef BOOST_IOSTREAMS_BASIC_IOS(Ch, traits_type)       ios_type;
0054         typedef BOOST_IOSTREAMS_BASIC_STREAMBUF(Ch, traits_type) streambuf_type;
0055         scoped_redirector( ios_type& ios,
0056                            streambuf_type* newbuf )
0057             : ios_(ios), old_(ios.rdbuf(newbuf))
0058             { }
0059         ~scoped_redirector() { ios_.rdbuf(old_); }
0060         scoped_redirector& operator=(const scoped_redirector&);
0061         ios_type&        ios_;
0062         streambuf_type*  old_;
0063     };
0064
0065     virtual void do_filter() = 0;
0066     virtual void do_filter(const vector_type& src, vector_type& dest)
0067     {
0068         stream_buffer< basic_array_source<Ch> >
0069                           srcbuf(&src[0], &src[0] + src.size());
0070         stream_buffer< back_insert_device<vector_type> >
0071                           destbuf(iostreams::back_inserter(dest));
0072         scoped_redirector redirect_input(standard_input((Ch*)0), &srcbuf);
0073         scoped_redirector redirect_output(standard_output((Ch*)0), &destbuf);
0074         do_filter();
0075     }
0076 };
0077 BOOST_IOSTREAMS_PIPABLE(basic_stdio_filter, 2)
0078
0079 typedef basic_stdio_filter<char>     stdio_filter;
0080 typedef basic_stdio_filter<wchar_t>  wstdio_wfilter;
0081
0082 } } // End namespaces iostreams, boost.
0083
0084 #endif // #ifndef BOOST_IOSTREAMS_STDIO_FILTER_HPP_INCLUDED