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clang-format applied to a downcasting header

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Mateusz Pusz
2020-01-31 17:03:35 +01:00
parent 9cdc3e1ad2
commit 0354c56ac2
1 changed files with 37 additions and 36 deletions
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73
src/include/units/bits/external/downcasting.h vendored
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@@ -27,46 +27,47 @@
namespace units { namespace units {
template<typename BaseType> template<typename BaseType>
struct downcast_base { struct downcast_base {
using downcast_base_type = BaseType; using downcast_base_type = BaseType;
friend auto downcast_guide(downcast_base); friend auto downcast_guide(downcast_base);
};
template<typename T>
concept Downcastable =
requires {
typename T::downcast_base_type;
} &&
std::derived_from<T, downcast_base<typename T::downcast_base_type>>;
template<typename Target, Downcastable T>
struct downcast_child : T {
friend auto downcast_guide(typename downcast_child::downcast_base /* base */) { return Target(); }
};
namespace detail {
template<typename T>
concept has_downcast =
requires {
downcast_guide(std::declval<downcast_base<T>>());
}; };
template<typename T> template<typename T>
concept Downcastable = constexpr auto downcast_impl()
requires { {
typename T::downcast_base_type; if constexpr (has_downcast<T>)
} && return decltype(downcast_guide(std::declval<downcast_base<T>>()))();
std::derived_from<T, downcast_base<typename T::downcast_base_type>>; else
return T();
}
template<typename Target, Downcastable T> } // namespace detail
struct downcast_child : T {
friend auto downcast_guide(typename downcast_child::downcast_base) { return Target(); }
};
namespace detail { template<Downcastable T>
using downcast = decltype(detail::downcast_impl<T>());
template<typename T> template<Downcastable T>
concept has_downcast = requires { using downcast_base_t = T::downcast_base_type;
downcast_guide(std::declval<downcast_base<T>>());
};
template<typename T>
constexpr auto downcast_impl()
{
if constexpr(has_downcast<T>)
return decltype(downcast_guide(std::declval<downcast_base<T>>()))();
else
return T();
}
}
template<Downcastable T>
using downcast = decltype(detail::downcast_impl<T>());
template<Downcastable T>
using downcast_base_t = T::downcast_base_type;
} // namespace units } // namespace units