boost/type_traits/integral_constant.hpp

   1 //  (C) Copyright John Maddock 2005.
   2 //  Use, modification and distribution are subject to the
   3 //  Boost Software License, Version 1.0. (See accompanying file
   4 //  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   5
   6 #ifndef BOOST_TYPE_TRAITS_INTEGRAL_CONSTANT_HPP
   7 #define BOOST_TYPE_TRAITS_INTEGRAL_CONSTANT_HPP
   8
   9 #include <boost/config.hpp>
  10 #include <boost/mpl/bool.hpp>
  11 #include <boost/mpl/integral_c.hpp>
  12
  13 namespace boost{
  14
  15 #if defined(BOOST_NO_DEPENDENT_TYPES_IN_TEMPLATE_VALUE_PARAMETERS) || defined(__BORLANDC__)
  16 template <class T, int val>
  17 #else
  18 template <class T, T val>
  19 #endif
  20 struct integral_constant : public mpl::integral_c<T, val>
  21 {
  22    typedef integral_constant<T,val> type;
  23 };
  24
  25 template<> struct integral_constant<bool,true> : public mpl::true_
  26 {
  27 #if BOOST_WORKAROUND(BOOST_MSVC, < 1300)
  28 # pragma warning(push)
  29 # pragma warning(disable:4097)
  30    typedef mpl::true_ base_;
  31    using base_::value;
  32 # pragma warning(pop)
  33 #endif
  34    typedef integral_constant<bool,true> type;
  35 };
  36 template<> struct integral_constant<bool,false> : public mpl::false_
  37 {
  38 #if BOOST_WORKAROUND(BOOST_MSVC, < 1300)
  39 # pragma warning(push)
  40 # pragma warning(disable:4097)
  41    typedef mpl::false_ base_;
  42    using base_::value;
  43 # pragma warning(pop)
  44 #endif
  45    typedef integral_constant<bool,false> type;
  46 };
  47
  48 typedef integral_constant<bool,true> true_type;
  49 typedef integral_constant<bool,false> false_type;
  50
  51 }
  52
  53 #endif