boost/boost/iostreams/flush.hpp

   1 // (C) Copyright Jonathan Turkanis 2003.
   2 // Distributed under the Boost Software License, Version 1.0. (See accompanying
   3 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt.)
   4
   5 // See http://www.boost.org/libs/iostreams for documentation.
   6
   7 #ifndef BOOST_IOSTREAMS_FLUSH_HPP_INCLUDED
   8 #define BOOST_IOSTREAMS_FLUSH_HPP_INCLUDED
   9
  10 #if defined(_MSC_VER) && (_MSC_VER >= 1020)
  11 # pragma once
  12 #endif
  13
  14 #include <boost/config.hpp>  // DEDUCED_TYPENAME, MSVC.
  15 #include <boost/detail/workaround.hpp>
  16 #include <boost/iostreams/detail/dispatch.hpp>
  17 #include <boost/iostreams/detail/streambuf.hpp>
  18 #include <boost/iostreams/detail/wrap_unwrap.hpp>
  19 #include <boost/iostreams/operations_fwd.hpp>
  20 #include <boost/iostreams/traits.hpp>
  21 #include <boost/mpl/if.hpp>
  22
  23 // Must come last.
  24 #include <boost/iostreams/detail/config/disable_warnings.hpp>
  25
  26 namespace boost { namespace iostreams {
  27
  28 namespace detail {
  29
  30 template<typename T>
  31 struct flush_device_impl;
  32
  33 template<typename T>
  34 struct flush_filter_impl;
  35
  36 } // End namespace detail.
  37
  38 template<typename T>
  39 bool flush(T& t)
  40 { return detail::flush_device_impl<T>::flush(detail::unwrap(t)); }
  41
  42 template<typename T, typename Sink>
  43 bool flush(T& t, Sink& snk)
  44 { return detail::flush_filter_impl<T>::flush(detail::unwrap(t), snk); }
  45
  46 namespace detail {
  47
  48 //------------------Definition of flush_device_impl---------------------------//
  49
  50 template<typename T>
  51 struct flush_device_impl
  52     : mpl::if_<
  53           is_custom<T>,
  54           operations<T>,
  55           flush_device_impl<
  56               BOOST_DEDUCED_TYPENAME
  57               dispatch<
  58                   T, ostream_tag, streambuf_tag, flushable_tag, any_tag
  59               >::type
  60           >
  61       >::type
  62     { };
  63
  64 template<>
  65 struct flush_device_impl<ostream_tag> {
  66     template<typename T>
  67     static bool flush(T& t)
  68     { return t.rdbuf()->BOOST_IOSTREAMS_PUBSYNC() == 0; }
  69 };
  70
  71 template<>
  72 struct flush_device_impl<streambuf_tag> {
  73     template<typename T>
  74     static bool flush(T& t)
  75     { return t.BOOST_IOSTREAMS_PUBSYNC() == 0; }
  76 };
  77
  78 template<>
  79 struct flush_device_impl<flushable_tag> {
  80     template<typename T>
  81     static bool flush(T& t) { return t.flush(); }
  82 };
  83
  84 template<>
  85 struct flush_device_impl<any_tag> {
  86     template<typename T>
  87     static bool flush(T&) { return true; }
  88 };
  89
  90 //------------------Definition of flush_filter_impl---------------------------//
  91
  92 template<typename T>
  93 struct flush_filter_impl
  94     : mpl::if_<
  95           is_custom<T>,
  96           operations<T>,
  97           flush_filter_impl<
  98               BOOST_DEDUCED_TYPENAME
  99               dispatch<
 100                   T, flushable_tag, any_tag
 101               >::type
 102           >
 103       >::type
 104     { };
 105
 106 template<>
 107 struct flush_filter_impl<flushable_tag> {
 108     template<typename T, typename Sink>
 109     static bool flush(T& t, Sink& snk) { return t.flush(snk); }
 110 };
 111
 112 template<>
 113 struct flush_filter_impl<any_tag> {
 114     template<typename T, typename Sink>
 115     static bool flush(T&, Sink&) { return false; }
 116 };
 117
 118 } // End namespace detail.
 119
 120 } } // End namespaces iostreams, boost.
 121
 122 #include <boost/iostreams/detail/config/enable_warnings.hpp>
 123
 124 #endif // #ifndef BOOST_IOSTREAMS_FLUSH_HPP_INCLUDED