boost/iostreams/flush.hpp

   1 // (C) Copyright 2008 CodeRage, LLC (turkanis at coderage dot com)
   2 // (C) Copyright 2003-2007 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 #ifndef BOOST_IOSTREAMS_FLUSH_HPP_INCLUDED
   9 #define BOOST_IOSTREAMS_FLUSH_HPP_INCLUDED
  10
  11 #if defined(_MSC_VER) && (_MSC_VER >= 1020)
  12 # pragma once
  13 #endif
  14
  15 #include <boost/config.hpp>  // DEDUCED_TYPENAME, MSVC.
  16 #include <boost/detail/workaround.hpp>
  17 #include <boost/iostreams/detail/dispatch.hpp>
  18 #include <boost/iostreams/detail/streambuf.hpp>
  19 #include <boost/iostreams/detail/wrap_unwrap.hpp>
  20 #include <boost/iostreams/operations_fwd.hpp>
  21 #include <boost/iostreams/traits.hpp>
  22 #include <boost/mpl/if.hpp>
  23
  24 // Must come last.
  25 #include <boost/iostreams/detail/config/disable_warnings.hpp>
  26
  27 namespace boost { namespace iostreams {
  28
  29 namespace detail {
  30
  31 template<typename T>
  32 struct flush_device_impl;
  33
  34 template<typename T>
  35 struct flush_filter_impl;
  36
  37 } // End namespace detail.
  38
  39 template<typename T>
  40 bool flush(T& t)
  41 { return detail::flush_device_impl<T>::flush(detail::unwrap(t)); }
  42
  43 template<typename T, typename Sink>
  44 bool flush(T& t, Sink& snk)
  45 { return detail::flush_filter_impl<T>::flush(detail::unwrap(t), snk); }
  46
  47 namespace detail {
  48
  49 //------------------Definition of flush_device_impl---------------------------//
  50
  51 template<typename T>
  52 struct flush_device_impl
  53     : mpl::if_<
  54           is_custom<T>,
  55           operations<T>,
  56           flush_device_impl<
  57               BOOST_DEDUCED_TYPENAME
  58               dispatch<
  59                   T, ostream_tag, streambuf_tag, flushable_tag, any_tag
  60               >::type
  61           >
  62       >::type
  63     { };
  64
  65 template<>
  66 struct flush_device_impl<ostream_tag> {
  67     template<typename T>
  68     static bool flush(T& t)
  69     { return t.rdbuf()->BOOST_IOSTREAMS_PUBSYNC() == 0; }
  70 };
  71
  72 template<>
  73 struct flush_device_impl<streambuf_tag> {
  74     template<typename T>
  75     static bool flush(T& t)
  76     { return t.BOOST_IOSTREAMS_PUBSYNC() == 0; }
  77 };
  78
  79 template<>
  80 struct flush_device_impl<flushable_tag> {
  81     template<typename T>
  82     static bool flush(T& t) { return t.flush(); }
  83 };
  84
  85 template<>
  86 struct flush_device_impl<any_tag> {
  87     template<typename T>
  88     static bool flush(T&) { return true; }
  89 };
  90
  91 //------------------Definition of flush_filter_impl---------------------------//
  92
  93 template<typename T>
  94 struct flush_filter_impl
  95     : mpl::if_<
  96           is_custom<T>,
  97           operations<T>,
  98           flush_filter_impl<
  99               BOOST_DEDUCED_TYPENAME
 100               dispatch<
 101                   T, flushable_tag, any_tag
 102               >::type
 103           >
 104       >::type
 105     { };
 106
 107 template<>
 108 struct flush_filter_impl<flushable_tag> {
 109     template<typename T, typename Sink>
 110     static bool flush(T& t, Sink& snk) { return t.flush(snk); }
 111 };
 112
 113 template<>
 114 struct flush_filter_impl<any_tag> {
 115     template<typename T, typename Sink>
 116     static bool flush(T&, Sink&) { return false; }
 117 };
 118
 119 } // End namespace detail.
 120
 121 } } // End namespaces iostreams, boost.
 122
 123 #include <boost/iostreams/detail/config/enable_warnings.hpp>
 124
 125 #endif // #ifndef BOOST_IOSTREAMS_FLUSH_HPP_INCLUDED