| // (C) Copyright John Maddock 2015. |
| // Use, modification and distribution are subject to the |
| // Boost Software License, Version 1.0. (See accompanying file |
| // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) |
| |
| #ifndef BOOST_TYPE_TRAITS_INTEGRAL_CONSTANT_HPP |
| #define BOOST_TYPE_TRAITS_INTEGRAL_CONSTANT_HPP |
| |
| #include <boost/config.hpp> |
| #include <boost/detail/workaround.hpp> |
| |
| #if (BOOST_WORKAROUND(BOOST_MSVC, BOOST_TESTED_AT(1400)) \ |
| || BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x610)) \ |
| || BOOST_WORKAROUND(__DMC__, BOOST_TESTED_AT(0x840)) \ |
| || BOOST_WORKAROUND(__MWERKS__, BOOST_TESTED_AT(0x3202)) \ |
| || BOOST_WORKAROUND(BOOST_INTEL_CXX_VERSION, BOOST_TESTED_AT(810)) ) |
| |
| |
| namespace boost{ |
| namespace mpl |
| { |
| template <bool B> struct bool_; |
| template <class I, I val> struct integral_c; |
| struct integral_c_tag; |
| } |
| } |
| |
| #else |
| |
| namespace mpl_{ |
| |
| template <bool B> struct bool_; |
| template <class I, I val> struct integral_c; |
| struct integral_c_tag; |
| } |
| |
| namespace boost |
| { |
| namespace mpl |
| { |
| using ::mpl_::bool_; |
| using ::mpl_::integral_c; |
| using ::mpl_::integral_c_tag; |
| } |
| } |
| |
| #endif |
| |
| namespace boost{ |
| |
| template <class T, T val> |
| struct integral_constant |
| { |
| typedef mpl::integral_c_tag tag; |
| typedef T value_type; |
| typedef integral_constant<T, val> type; |
| static const T value = val; |
| // |
| // This helper function is just to disable type-punning |
| // warnings from GCC: |
| // |
| template <class U> |
| static U& dereference(U* p) { return *p; } |
| |
| operator const mpl::integral_c<T, val>& ()const |
| { |
| static const char data[sizeof(long)] = { 0 }; |
| return dereference(reinterpret_cast<const mpl::integral_c<T, val>*>(&data)); |
| } |
| BOOST_CONSTEXPR operator T()const { return val; } |
| }; |
| |
| template <class T, T val> |
| T const integral_constant<T, val>::value; |
| |
| template <bool val> |
| struct integral_constant<bool, val> |
| { |
| typedef mpl::integral_c_tag tag; |
| typedef bool value_type; |
| typedef integral_constant<bool, val> type; |
| static const bool value = val; |
| // |
| // This helper function is just to disable type-punning |
| // warnings from GCC: |
| // |
| template <class T> |
| static T& dereference(T* p) { return *p; } |
| |
| operator const mpl::bool_<val>& ()const |
| { |
| static const char data = 0; |
| return dereference(reinterpret_cast<const mpl::bool_<val>*>(&data)); |
| } |
| BOOST_CONSTEXPR operator bool()const { return val; } |
| }; |
| |
| template <bool val> |
| bool const integral_constant<bool, val>::value; |
| |
| typedef integral_constant<bool, true> true_type; |
| typedef integral_constant<bool, false> false_type; |
| |
| } |
| |
| #endif |