ceph/src/boost/libs/iostreams/include/boost/iostreams/detail/bool_trait_def.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_DETAIL_BOOL_TRAIT_DEF_HPP_INCLUDED
   9 #define BOOST_IOSTREAMS_DETAIL_BOOL_TRAIT_DEF_HPP_INCLUDED
  10
  11 #include <boost/config.hpp> // BOOST_STATIC_CONSTANT.
  12 #include <boost/iostreams/detail/template_params.hpp>
  13 #include <boost/mpl/aux_/lambda_support.hpp>
  14 #include <boost/mpl/bool.hpp>
  15 #include <boost/preprocessor/cat.hpp>
  16 #include <boost/preprocessor/repetition/enum_params.hpp>
  17 #include <boost/type_traits/detail/yes_no_type.hpp>
  18
  19 //
  20 // Macro name: BOOST_IOSTREAMS_BOOL_TRAIT_DEF
  21 // Description: Used to generate the traits classes is_istream, is_ostream,
  22 //      etc.
  23 //
  24 #if BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x582))
  25 # define BOOST_IOSTREAMS_TRAIT_NAMESPACE(trait)
  26 #else
  27 # define BOOST_IOSTREAMS_TRAIT_NAMESPACE(trait) BOOST_PP_CAT(trait, _impl_)::
  28 #endif
  29 #define BOOST_IOSTREAMS_BOOL_TRAIT_DEF(trait, type, arity) \
  30     namespace BOOST_PP_CAT(trait, _impl_) { \
  31       BOOST_IOSTREAMS_TEMPLATE_PARAMS(arity, T) \
  32       type_traits::yes_type helper \
  33           (const volatile type BOOST_IOSTREAMS_TEMPLATE_ARGS(arity, T)*); \
  34       type_traits::no_type helper(...); \
  35       template<typename T> \
  36       struct impl { \
  37            BOOST_STATIC_CONSTANT(bool, value = \
  38            (sizeof(BOOST_IOSTREAMS_TRAIT_NAMESPACE(trait) \
  39               helper(static_cast<T*>(0))) == \
  40                 sizeof(type_traits::yes_type))); \
  41       }; \
  42     } \
  43     template<typename T> \
  44     struct trait \
  45         : mpl::bool_<BOOST_PP_CAT(trait, _impl_)::impl<T>::value> \
  46     { BOOST_MPL_AUX_LAMBDA_SUPPORT(1, trait, (T)) }; \
  47     /**/
  48
  49 #endif // #ifndef BOOST_IOSTREAMS_DETAIL_BOOL_TRAIT_DEF_HPP_INCLUDED