ceph/src/boost/boost/type_traits/has_minus_assign.hpp

   1 //  (C) Copyright 2009-2011 Frederic Bron.
   2 //
   3 //  Use, modification and distribution are subject to the Boost Software License,
   4 //  Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
   5 //  http://www.boost.org/LICENSE_1_0.txt).
   6 //
   7 //  See http://www.boost.org/libs/type_traits for most recent version including documentation.
   8
   9 #ifndef BOOST_TT_has_minus_assign_ASSIGN_HPP_INCLUDED
  10 #define BOOST_TT_has_minus_assign_ASSIGN_HPP_INCLUDED
  11
  12 #include <boost/config.hpp>
  13 #include <boost/type_traits/detail/config.hpp>
  14
  15 // cannot include this header without getting warnings of the kind:
  16 // gcc:
  17 //    warning: value computed is not used
  18 //    warning: comparison between signed and unsigned integer expressions
  19 // msvc:
  20 //    warning C4018: '<' : signed/unsigned mismatch
  21 //    warning C4244: '+=' : conversion from 'double' to 'char', possible loss of data
  22 //    warning C4547: '*' : operator before comma has no effect; expected operator with side-effect
  23 //    warning C4800: 'int' : forcing value to bool 'true' or 'false' (performance warning)
  24 //    warning C4804: '<' : unsafe use of type 'bool' in operation
  25 //    warning C4805: '==' : unsafe mix of type 'bool' and type 'char' in operation
  26 // cannot find another implementation -> declared as system header to suppress these warnings.
  27 #if defined(__GNUC__)
  28 #   pragma GCC system_header
  29 #elif defined(BOOST_MSVC)
  30 #   pragma warning ( push )
  31 #   pragma warning ( disable : 4018 4244 4547 4800 4804 4805 4913 4133)
  32 #   if BOOST_WORKAROUND(BOOST_MSVC_FULL_VER, >= 140050000)
  33 #       pragma warning ( disable : 6334)
  34 #   endif
  35 #endif
  36
  37 #if defined(BOOST_TT_HAS_ACCURATE_BINARY_OPERATOR_DETECTION)
  38
  39 #include <boost/type_traits/integral_constant.hpp>
  40 #include <boost/type_traits/make_void.hpp>
  41 #include <boost/type_traits/is_convertible.hpp>
  42 #include <boost/type_traits/is_void.hpp>
  43 #include <boost/type_traits/is_pointer.hpp>
  44 #include <boost/type_traits/add_reference.hpp>
  45 #include <boost/type_traits/remove_pointer.hpp>
  46 #include <boost/type_traits/remove_reference.hpp>
  47 #include <utility>
  48
  49 namespace boost
  50 {
  51
  52    namespace binary_op_detail {
  53
  54       struct dont_care;
  55
  56       template <class T, class U, class Ret, class = boost::void_t<>>
  57       struct has_minus_assign_ret_imp : public boost::false_type {};
  58
  59       template <class T, class U, class Ret>
  60       struct has_minus_assign_ret_imp<T, U, Ret, boost::void_t<decltype(std::declval<typename add_reference<T>::type>() -= std::declval<typename add_reference<U>::type>())> >
  61          : 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> {};
  62
  63       template <class T, class U, class = boost::void_t<> >
  64       struct has_minus_assign_void_imp : public boost::false_type {};
  65
  66       template <class T, class U>
  67       struct has_minus_assign_void_imp<T, U, boost::void_t<decltype(std::declval<typename add_reference<T>::type>() -= std::declval<typename add_reference<U>::type>())> >
  68          : public boost::integral_constant<bool, ::boost::is_void<decltype(std::declval<typename add_reference<T>::type>() -= std::declval<typename add_reference<U>::type>())>::value> {};
  69
  70       template <class T, class U, class = boost::void_t<>>
  71       struct has_minus_assign_dc_imp : public boost::false_type {};
  72
  73       template <class T, class U>
  74       struct has_minus_assign_dc_imp<T, U, boost::void_t<decltype(std::declval<typename add_reference<T>::type>() -= std::declval<typename add_reference<U>::type>())> >
  75          : public boost::true_type {};
  76
  77       template <class T, class U, class Ret>
  78       struct has_minus_assign_ret_filter : public boost::binary_op_detail::has_minus_assign_ret_imp <T, U, Ret> {};
  79       template <class T, class U>
  80       struct has_minus_assign_ret_filter<T, U, void> : public boost::binary_op_detail::has_minus_assign_void_imp <T, U> {};
  81       template <class T, class U>
  82       struct has_minus_assign_ret_filter<T, U, boost::binary_op_detail::dont_care> : public boost::binary_op_detail::has_minus_assign_dc_imp <T, U> {};
  83
  84       template <class T, class U, class Ret, bool b>
  85       struct has_minus_assign_void_ptr_filter : public boost::binary_op_detail::has_minus_assign_ret_filter <T, U, Ret> {};
  86       template <class T, class U, class Ret>
  87       struct has_minus_assign_void_ptr_filter<T, U, Ret, true> : public boost::false_type {};
  88
  89    }
  90
  91    template <class T, class U = T, class Ret = boost::binary_op_detail::dont_care>
  92    struct has_minus_assign :
  93       public boost::binary_op_detail::has_minus_assign_void_ptr_filter<
  94       T, U, Ret,
  95       boost::is_void<typename remove_pointer<typename remove_reference<T>::type>::type>::value
  96       || boost::is_void<typename remove_pointer<typename remove_reference<U>::type>::type>::value
  97       || (boost::is_pointer<typename remove_reference<T>::type>::value && boost::is_pointer<typename remove_reference<U>::type>::value)> {};
  98
  99
 100 }
 101
 102 #else
 103
 104 #define BOOST_TT_TRAIT_NAME has_minus_assign
 105 #define BOOST_TT_TRAIT_OP -=
 106 #define BOOST_TT_FORBIDDEN_IF\
 107    (\
 108       /* Lhs==pointer and Rhs==fundamental and Rhs!=integral */\
 109       (\
 110          ::boost::is_pointer< Lhs_noref >::value && \
 111          ::boost::is_fundamental< Rhs_nocv >::value && \
 112          (!  ::boost::is_integral< Rhs_noref >::value )\
 113       ) || \
 114       /* Lhs==void* and Rhs==fundamental */\
 115       (\
 116          ::boost::is_pointer< Lhs_noref >::value && \
 117          ::boost::is_void< Lhs_noptr >::value && \
 118          ::boost::is_fundamental< Rhs_nocv >::value\
 119       ) || \
 120       /* Rhs==void* and Lhs==fundamental */\
 121       (\
 122          ::boost::is_pointer< Rhs_noref >::value && \
 123          ::boost::is_void< Rhs_noptr >::value && \
 124          ::boost::is_fundamental< Lhs_nocv >::value\
 125       ) || \
 126       /* Lhs=fundamental and Rhs=pointer */\
 127       (\
 128          ::boost::is_fundamental< Lhs_nocv >::value && \
 129          ::boost::is_pointer< Rhs_noref >::value\
 130       ) || \
 131       /* Lhs==pointer and Rhs==pointer */\
 132       (\
 133          ::boost::is_pointer< Lhs_noref >::value && \
 134          ::boost::is_pointer< Rhs_noref >::value\
 135       ) || \
 136       /* (Lhs==fundamental or Lhs==pointer) and (Rhs==fundamental or Rhs==pointer) and (Lhs==const) */\
 137       (\
 138          (\
 139             ::boost::is_fundamental< Lhs_nocv >::value || \
 140             ::boost::is_pointer< Lhs_noref >::value\
 141          ) && \
 142          (\
 143             ::boost::is_fundamental< Rhs_nocv >::value || \
 144             ::boost::is_pointer< Rhs_noref >::value\
 145           ) && \
 146          ::boost::is_const< Lhs_noref >::value\
 147       )\
 148       )
 149
 150
 151 #include <boost/type_traits/detail/has_binary_operator.hpp>
 152
 153 #undef BOOST_TT_TRAIT_NAME
 154 #undef BOOST_TT_TRAIT_OP
 155 #undef BOOST_TT_FORBIDDEN_IF
 156
 157 #endif
 158 #endif