boost/type_traits/has_minus.hpp
// (C) Copyright 2009-2011 Frederic Bron. // // 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_HAS_MINUS_HPP_INCLUDED #define BOOST_TT_HAS_MINUS_HPP_INCLUDED #include <boost/config.hpp> #include <boost/type_traits/detail/config.hpp> // cannot include this header without getting warnings of the kind: // gcc: // warning: value computed is not used // warning: comparison between signed and unsigned integer expressions // msvc: // warning C4018: '<' : signed/unsigned mismatch // warning C4244: '+=' : conversion from 'double' to 'char', possible loss of data // warning C4547: '*' : operator before comma has no effect; expected operator with side-effect // warning C4800: 'int' : forcing value to bool 'true' or 'false' (performance warning) // warning C4804: '<' : unsafe use of type 'bool' in operation // warning C4805: '==' : unsafe mix of type 'bool' and type 'char' in operation // cannot find another implementation -> declared as system header to suppress these warnings. #if defined(__GNUC__) # pragma GCC system_header #elif defined(BOOST_MSVC) # pragma warning ( push ) # pragma warning ( disable : 4018 4244 4547 4800 4804 4805 4913 4133) # if BOOST_WORKAROUND(BOOST_MSVC_FULL_VER, >= 140050000) # pragma warning ( disable : 6334) # endif #endif #if defined(BOOST_TT_HAS_ACCURATE_BINARY_OPERATOR_DETECTION) #include <boost/type_traits/integral_constant.hpp> #include <boost/type_traits/make_void.hpp> #include <boost/type_traits/is_convertible.hpp> #include <boost/type_traits/is_void.hpp> #include <boost/type_traits/add_reference.hpp> #include <boost/type_traits/remove_pointer.hpp> #include <boost/type_traits/remove_reference.hpp> #include <utility> namespace boost { namespace binary_op_detail { struct dont_care; template <class T, class U, class Ret, class = void> struct has_minus_ret_imp : public boost::false_type {}; template <class T, class U, class Ret> struct has_minus_ret_imp<T, U, Ret, typename boost::make_void<decltype(std::declval<typename add_reference<T>::type>() - std::declval<typename add_reference<U>::type>())>::type> : public boost::integral_constant<bool, ::boost::is_convertible<decltype(std::declval<typename add_reference<T>::type>() - std::declval<typename add_reference<U>::type>()), Ret>::value> {}; template <class T, class U, class = void > struct has_minus_void_imp : public boost::false_type {}; template <class T, class U> struct has_minus_void_imp<T, U, typename boost::make_void<decltype(std::declval<typename add_reference<T>::type>() - std::declval<typename add_reference<U>::type>())>::type> : public boost::integral_constant<bool, ::boost::is_void<decltype(std::declval<typename add_reference<T>::type>() - std::declval<typename add_reference<U>::type>())>::value> {}; template <class T, class U, class = void> struct has_minus_dc_imp : public boost::false_type {}; template <class T, class U> struct has_minus_dc_imp<T, U, typename boost::make_void<decltype(std::declval<typename add_reference<T>::type>() - std::declval<typename add_reference<U>::type>())>::type> : public boost::true_type {}; template <class T, class U, class Ret> struct has_minus_ret_filter : public boost::binary_op_detail::has_minus_ret_imp <T, U, Ret> {}; template <class T, class U> struct has_minus_ret_filter<T, U, void> : public boost::binary_op_detail::has_minus_void_imp <T, U> {}; template <class T, class U> struct has_minus_ret_filter<T, U, boost::binary_op_detail::dont_care> : public boost::binary_op_detail::has_minus_dc_imp <T, U> {}; template <class T, class U, class Ret, bool b> struct has_minus_void_ptr_filter : public boost::binary_op_detail::has_minus_ret_filter <T, U, Ret> {}; template <class T, class U, class Ret> struct has_minus_void_ptr_filter<T, U, Ret, true> : public boost::false_type {}; } template <class T, class U = T, class Ret = boost::binary_op_detail::dont_care> struct has_minus : public boost::binary_op_detail::has_minus_void_ptr_filter< T, U, Ret, boost::is_void<typename remove_pointer<typename remove_reference<T>::type>::type>::value || boost::is_void<typename remove_pointer<typename remove_reference<U>::type>::type>::value> {}; } #else #define BOOST_TT_TRAIT_NAME has_minus #define BOOST_TT_TRAIT_OP - #define BOOST_TT_FORBIDDEN_IF\ (\ /* Lhs==pointer and Rhs==fundamental and Rhs!=integral */\ (\ ::boost::is_pointer< Lhs_noref >::value && \ ::boost::is_fundamental< Rhs_nocv >::value && \ (! ::boost::is_integral< Rhs_noref >::value )\ ) || \ /* Lhs==void* and (Rhs==fundamental or Rhs==pointer) */\ (\ ::boost::is_pointer< Lhs_noref >::value && \ ::boost::is_void< Lhs_noptr >::value && \ ( \ ::boost::is_fundamental< Rhs_nocv >::value || \ ::boost::is_pointer< Rhs_noref >::value\ )\ ) || \ /* Rhs==void* and (Lhs==fundamental or Lhs==pointer) */\ (\ ::boost::is_pointer< Rhs_noref >::value && \ ::boost::is_void< Rhs_noptr >::value && \ (\ ::boost::is_fundamental< Lhs_nocv >::value || \ ::boost::is_pointer< Lhs_noref >::value\ )\ ) ||\ /* Lhs=fundamental and Rhs=pointer */\ (\ ::boost::is_fundamental< Lhs_nocv >::value && \ ::boost::is_pointer< Rhs_noref >::value\ ) ||\ /* two different pointers */\ (\ ::boost::is_pointer< Lhs_noref >::value && \ ::boost::is_pointer< Rhs_noref >::value && \ (! ::boost::is_same< Lhs_nocv, Rhs_nocv >::value )\ )\ ) #define BOOST_TT_FORBIDDEN_IF_NEW (boost::is_void<typename remove_pointer<typename boost::remove_reference<T>::type>::type>::value || boost::is_void<typename remove_pointer<typename boost::remove_reference<U>::type>::type>::value) #include <boost/type_traits/detail/has_binary_operator.hpp> #undef BOOST_TT_TRAIT_NAME #undef BOOST_TT_TRAIT_OP #undef BOOST_TT_FORBIDDEN_IF #endif #if defined(BOOST_MSVC) # pragma warning (pop) #endif #endif