boost/iostreams/concepts.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_CONCEPTS_HPP_INCLUDED
   9 #define BOOST_IOSTREAMS_CONCEPTS_HPP_INCLUDED
  10
  11 #if defined(_MSC_VER) && (_MSC_VER >= 1020)
  12 # pragma once
  13 #endif
  14
  15 #include <boost/config.hpp>  // BOOST_MSVC
  16 #include <boost/detail/workaround.hpp>
  17 #include <boost/iostreams/categories.hpp>
  18 #include <boost/iostreams/detail/default_arg.hpp>
  19 #include <boost/iostreams/detail/ios.hpp>  // openmode.
  20 #include <boost/iostreams/positioning.hpp>
  21 #include <boost/static_assert.hpp>
  22 #include <boost/type_traits/is_convertible.hpp>
  23
  24 namespace boost { namespace iostreams {
  25
  26 //--------------Definitions of helper templates for device concepts-----------//
  27
  28 template<typename Mode, typename Ch = BOOST_IOSTREAMS_DEFAULT_ARG(char)>
  29 struct device {
  30     typedef Ch char_type;
  31     struct category
  32         : Mode,
  33           device_tag,
  34           closable_tag,
  35           localizable_tag
  36         { };
  37
  38     void close()
  39     {
  40         using namespace detail;
  41         BOOST_STATIC_ASSERT((!is_convertible<Mode, two_sequence>::value));
  42     }
  43
  44     void close(BOOST_IOS::openmode)
  45     {
  46         using namespace detail;
  47         BOOST_STATIC_ASSERT((is_convertible<Mode, two_sequence>::value));
  48     }
  49
  50     template<typename Locale>
  51     void imbue(const Locale&) { }
  52 };
  53
  54 template<typename Mode, typename Ch = BOOST_IOSTREAMS_DEFAULT_ARG(wchar_t)>
  55 struct wdevice : device<Mode, Ch> { };
  56
  57 typedef device<input>    source;
  58 typedef wdevice<input>   wsource;
  59 typedef device<output>   sink;
  60 typedef wdevice<output>  wsink;
  61
  62 //--------------Definitions of helper templates for simple filter concepts----//
  63
  64 template<typename Mode, typename Ch = BOOST_IOSTREAMS_DEFAULT_ARG(char)>
  65 struct filter {
  66     typedef Ch char_type;
  67     struct category
  68         : Mode,
  69           filter_tag,
  70           closable_tag,
  71           localizable_tag
  72         { };
  73
  74     template<typename Device>
  75     void close(Device&)
  76     {
  77         using namespace detail;
  78         BOOST_STATIC_ASSERT((!is_convertible<Mode, two_sequence>::value));
  79         BOOST_STATIC_ASSERT((!is_convertible<Mode, dual_use>::value));
  80     }
  81
  82     template<typename Device>
  83     void close(Device&, BOOST_IOS::openmode)
  84     {
  85         using namespace detail;
  86         BOOST_STATIC_ASSERT(
  87             (is_convertible<Mode, two_sequence>::value) ||
  88             (is_convertible<Mode, dual_use>::value)
  89         );
  90     }
  91
  92     template<typename Locale>
  93     void imbue(const Locale&) { }
  94 };
  95
  96 template<typename Mode, typename Ch = BOOST_IOSTREAMS_DEFAULT_ARG(wchar_t)>
  97 struct wfilter : filter<Mode, Ch> { };
  98
  99 typedef filter<input>      input_filter;
 100 typedef wfilter<input>     input_wfilter;
 101 typedef filter<output>     output_filter;
 102 typedef wfilter<output>    output_wfilter;
 103 typedef filter<seekable>   seekable_filter;
 104 typedef wfilter<seekable>  seekable_wfilter;
 105 typedef filter<dual_use>   dual_use_filter;
 106 typedef wfilter<dual_use>  dual_use_wfilter;
 107
 108 //------Definitions of helper templates for multi-character filter cncepts----//
 109
 110 template<typename Mode, typename Ch = char>
 111 struct multichar_filter : filter<Mode, Ch> {
 112     struct category : filter<Mode, Ch>::category, multichar_tag { };
 113 };
 114
 115 template<typename Mode, typename Ch = wchar_t>
 116 struct multichar_wfilter : multichar_filter<Mode, Ch> { };
 117
 118 typedef multichar_filter<input>      multichar_input_filter;
 119 typedef multichar_wfilter<input>     multichar_input_wfilter;
 120 typedef multichar_filter<output>     multichar_output_filter;
 121 typedef multichar_wfilter<output>    multichar_output_wfilter;
 122 typedef multichar_filter<dual_use>   multichar_dual_use_filter;
 123 typedef multichar_wfilter<dual_use>  multichar_dual_use_wfilter;
 124
 125 //----------------------------------------------------------------------------//
 126
 127 } } // End namespaces iostreams, boost.
 128
 129 #endif // #ifndef BOOST_IOSTREAMS_CONCEPTS_HPP_INCLUDED