traits.hpp

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#pragma once
 
#include <type_traits>
 
namespace opcua::detail {
 
template <typename... Ts>
struct Overload : Ts... {
    using Ts::operator()...;
};
 
template <typename... Ts>
Overload(Ts...) -> Overload<Ts...>;
 
template <typename...>
struct AlwaysFalse : std::false_type {};
 
template <typename T, typename... Ts>
using IsOneOf = std::disjunction<std::is_same<T, Ts>...>;
 
/// Derive member type from member pointer
template <typename T>
struct MemberType;
 
template <typename C, typename T>
struct MemberType<T C::*> {
    using type = T;
};
 
template <typename T>
using MemberTypeT = typename MemberType<T>::type;
 
template <typename T, typename = void>
struct IsContainer : std::false_type {};
 
template <typename T>
struct IsContainer<
    T,
    std::void_t<decltype(std::declval<T>().begin()), decltype(std::declval<T>().end())>>
    : std::true_type {};
 
template <typename T>
inline constexpr bool isContainer = IsContainer<T>::value;
 
template <typename T, typename = void>
struct IsContiguousContainer : std::false_type {};
 
template <typename T>
struct IsContiguousContainer<
    T,
    std::void_t<
        decltype(std::declval<T>().data()),
        decltype(std::declval<T>().size()),
        decltype(std::declval<T>().begin()),
        decltype(std::declval<T>().end())>> : std::true_type {
    using value_type = bool;
    // detect vector<bool>::data() void return type
    static constexpr bool value = std::is_pointer_v<decltype(std::declval<T>().data())>;
    using type = std::bool_constant<value>;
};
 
template <typename T>
struct IsMutableContainer
    : std::conjunction<
          std::is_same<
              decltype(std::declval<T>().begin()),
              typename std::remove_reference_t<T>::iterator>,
          std::is_same<
              decltype(std::declval<T>().end()),
              typename std::remove_reference_t<T>::iterator>,
          std::negation<std::is_same<
              typename std::remove_reference_t<T>::iterator,
              typename std::remove_reference_t<T>::const_iterator>>> {};
 
}  // namespace opcua::detail