boost/iostreams/flush.hpp

0001 // (C) Copyright 2008 CodeRage, LLC (turkanis at coderage dot com)
0002 // (C) Copyright 2003-2007 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 #ifndef BOOST_IOSTREAMS_FLUSH_HPP_INCLUDED
0009 #define BOOST_IOSTREAMS_FLUSH_HPP_INCLUDED
0010
0011 #if defined(_MSC_VER)
0012 # pragma once
0013 #endif
0014
0015 #include <boost/config.hpp>  // DEDUCED_TYPENAME, MSVC.
0016 #include <boost/detail/workaround.hpp>
0017 #include <boost/iostreams/detail/dispatch.hpp>
0018 #include <boost/iostreams/detail/streambuf.hpp>
0019 #include <boost/iostreams/detail/wrap_unwrap.hpp>
0020 #include <boost/iostreams/operations_fwd.hpp>
0021 #include <boost/iostreams/traits.hpp>
0022 #include <boost/mpl/if.hpp>
0023
0024 // Must come last.
0025 #include <boost/iostreams/detail/config/disable_warnings.hpp>
0026
0027 namespace boost { namespace iostreams {
0028
0029 namespace detail {
0030
0031 template<typename T>
0032 struct flush_device_impl;
0033
0034 template<typename T>
0035 struct flush_filter_impl;
0036
0037 } // End namespace detail.
0038
0039 template<typename T>
0040 bool flush(T& t)
0041 { return detail::flush_device_impl<T>::flush(detail::unwrap(t)); }
0042
0043 template<typename T, typename Sink>
0044 bool flush(T& t, Sink& snk)
0045 { return detail::flush_filter_impl<T>::flush(detail::unwrap(t), snk); }
0046
0047 namespace detail {
0048
0049 //------------------Definition of flush_device_impl---------------------------//
0050
0051 template<typename T>
0052 struct flush_device_impl
0053     : mpl::if_<
0054           is_custom<T>,
0055           operations<T>,
0056           flush_device_impl<
0057               BOOST_DEDUCED_TYPENAME
0058               dispatch<
0059                   T, ostream_tag, streambuf_tag, flushable_tag, any_tag
0060               >::type
0061           >
0062       >::type
0063     { };
0064
0065 template<>
0066 struct flush_device_impl<ostream_tag> {
0067     template<typename T>
0068     static bool flush(T& t)
0069     { return t.rdbuf()->BOOST_IOSTREAMS_PUBSYNC() == 0; }
0070 };
0071
0072 template<>
0073 struct flush_device_impl<streambuf_tag> {
0074     template<typename T>
0075     static bool flush(T& t)
0076     { return t.BOOST_IOSTREAMS_PUBSYNC() == 0; }
0077 };
0078
0079 template<>
0080 struct flush_device_impl<flushable_tag> {
0081     template<typename T>
0082     static bool flush(T& t) { return t.flush(); }
0083 };
0084
0085 template<>
0086 struct flush_device_impl<any_tag> {
0087     template<typename T>
0088     static bool flush(T&) { return true; }
0089 };
0090
0091 //------------------Definition of flush_filter_impl---------------------------//
0092
0093 template<typename T>
0094 struct flush_filter_impl
0095     : mpl::if_<
0096           is_custom<T>,
0097           operations<T>,
0098           flush_filter_impl<
0099               BOOST_DEDUCED_TYPENAME
0100               dispatch<
0101                   T, flushable_tag, any_tag
0102               >::type
0103           >
0104       >::type
0105     { };
0106
0107 template<>
0108 struct flush_filter_impl<flushable_tag> {
0109     template<typename T, typename Sink>
0110     static bool flush(T& t, Sink& snk) { return t.flush(snk); }
0111 };
0112
0113 template<>
0114 struct flush_filter_impl<any_tag> {
0115     template<typename T, typename Sink>
0116     static bool flush(T&, Sink&) { return false; }
0117 };
0118
0119 } // End namespace detail.
0120
0121 } } // End namespaces iostreams, boost.
0122
0123 #include <boost/iostreams/detail/config/enable_warnings.hpp>
0124
0125 #endif // #ifndef BOOST_IOSTREAMS_FLUSH_HPP_INCLUDED