boost/type_traits/is_enum.hpp
// (C) Copyright Dave Abrahams, Steve Cleary, Beman Dawes, Howard
// Hinnant & John Maddock 2000.
// 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).
//
// See http://www.boost.org/libs/type_traits for most recent version including documentation.
#ifndef BOOST_TT_IS_ENUM_HPP_INCLUDED
#define BOOST_TT_IS_ENUM_HPP_INCLUDED
#include <boost/type_traits/intrinsics.hpp>
#include <boost/type_traits/integral_constant.hpp>
#ifndef BOOST_IS_ENUM
#include <boost/type_traits/add_reference.hpp>
#include <boost/type_traits/is_arithmetic.hpp>
#include <boost/type_traits/is_reference.hpp>
#include <boost/type_traits/is_convertible.hpp>
#include <boost/type_traits/is_array.hpp>
#ifdef __GNUC__
#include <boost/type_traits/is_function.hpp>
#endif
#include <boost/type_traits/detail/config.hpp>
#if defined(BOOST_TT_HAS_CONFORMING_IS_CLASS_IMPLEMENTATION)
# include <boost/type_traits/is_class.hpp>
# include <boost/type_traits/is_union.hpp>
#endif
#endif
namespace boost {
#ifndef BOOST_IS_ENUM
#if !(defined(__BORLANDC__) && (__BORLANDC__ <= 0x551))
namespace detail {
#if defined(BOOST_TT_HAS_CONFORMING_IS_CLASS_IMPLEMENTATION)
template <typename T>
struct is_class_or_union
{
BOOST_STATIC_CONSTANT(bool, value = ::boost::is_class<T>::value || ::boost::is_union<T>::value);
};
#else
template <typename T>
struct is_class_or_union
{
# if BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x581))// we simply can't detect it this way.
BOOST_STATIC_CONSTANT(bool, value = false);
# else
template <class U> static ::boost::type_traits::yes_type is_class_or_union_tester(void(U::*)(void));
# if BOOST_WORKAROUND(__MWERKS__, <= 0x3000) // no SFINAE
static ::boost::type_traits::no_type is_class_or_union_tester(...);
BOOST_STATIC_CONSTANT(
bool, value = sizeof(is_class_or_union_tester(0)) == sizeof(::boost::type_traits::yes_type));
# else
template <class U>
static ::boost::type_traits::no_type is_class_or_union_tester(...);
BOOST_STATIC_CONSTANT(
bool, value = sizeof(is_class_or_union_tester<T>(0)) == sizeof(::boost::type_traits::yes_type));
# endif
# endif
};
#endif
struct int_convertible
{
int_convertible(int);
};
// Don't evaluate convertibility to int_convertible unless the type
// is non-arithmetic. This suppresses warnings with GCC.
template <bool is_typename_arithmetic_or_reference = true>
struct is_enum_helper
{
template <typename T> struct type
{
BOOST_STATIC_CONSTANT(bool, value = false);
};
};
template <>
struct is_enum_helper<false>
{
template <typename T> struct type
{
static const bool value = ::boost::is_convertible<typename boost::add_reference<T>::type, ::boost::detail::int_convertible>::value;
};
};
template <typename T> struct is_enum_impl
{
//typedef ::boost::add_reference<T> ar_t;
//typedef typename ar_t::type r_type;
#if defined(__GNUC__)
#ifdef BOOST_TT_HAS_CONFORMING_IS_CLASS_IMPLEMENTATION
// We MUST check for is_class_or_union on conforming compilers in
// order to correctly deduce that noncopyable types are not enums
// (dwa 2002/04/15)...
BOOST_STATIC_CONSTANT(bool, selector =
::boost::is_arithmetic<T>::value
|| ::boost::is_reference<T>::value
|| ::boost::is_function<T>::value
|| is_class_or_union<T>::value
|| is_array<T>::value);
#else
// ...however, not checking is_class_or_union on non-conforming
// compilers prevents a dependency recursion.
BOOST_STATIC_CONSTANT(bool, selector =
::boost::is_arithmetic<T>::value
|| ::boost::is_reference<T>::value
|| ::boost::is_function<T>::value
|| is_array<T>::value);
#endif // BOOST_TT_HAS_CONFORMING_IS_CLASS_IMPLEMENTATION
#else // !defined(__GNUC__):
BOOST_STATIC_CONSTANT(bool, selector =
::boost::is_arithmetic<T>::value
|| ::boost::is_reference<T>::value
|| is_class_or_union<T>::value
|| is_array<T>::value);
#endif
#if BOOST_WORKAROUND(__BORLANDC__, < 0x600)
typedef ::boost::detail::is_enum_helper<
::boost::detail::is_enum_impl<T>::selector
> se_t;
#else
typedef ::boost::detail::is_enum_helper<selector> se_t;
#endif
typedef typename se_t::template type<T> helper;
BOOST_STATIC_CONSTANT(bool, value = helper::value);
};
} // namespace detail
template <class T> struct is_enum : public integral_constant<bool, ::boost::detail::is_enum_impl<T>::value> {};
#else // __BORLANDC__
//
// buggy is_convertible prevents working
// implementation of is_enum:
template <class T> struct is_enum : public integral_constant<bool, false> {};
#endif
#else // BOOST_IS_ENUM
template <class T> struct is_enum : public integral_constant<bool, BOOST_IS_ENUM(T)> {};
#endif
} // namespace boost
#endif // BOOST_TT_IS_ENUM_HPP_INCLUDED