AMReX_Any.H

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#ifndef AMREX_ANY_H_
#define AMREX_ANY_H_
#include <AMReX_Config.H>
 
#include <concepts>
#include <memory>
#include <typeinfo>
#include <type_traits>
 
namespace amrex {
 
class Any
{
public:
 
    Any () = default;
    ~Any () = default;
 
    Any (Any const& rhs) = delete;
    Any& operator= (Any const& rhs) = delete;
 
    Any (Any && rhs) = default;
    Any& operator= (Any && rhs) = default;
 
    template <typename MF>
    requires (!std::same_as<Any,std::remove_cvref_t<MF>>)
    Any (MF && mf) // NOLINT(bugprone-forwarding-reference-overload)
        : m_ptr(std::make_unique<innards<MF> >(std::forward<MF>(mf)))
        {}
 
    template <typename MF>
    requires (!std::same_as<Any,std::remove_cvref_t<MF>>)
    Any& operator= (MF && mf)
    {
        m_ptr = std::make_unique<innards<MF> >(std::forward<MF>(mf));
        return *this;
    }
 
    [[nodiscard]] const std::type_info& Type () const {
        if (m_ptr) {
            return m_ptr->Type();
        } else {
            return typeid(void);
        }
    }
 
    template <typename MF>
    [[nodiscard]] MF& get () {
        if (auto p0 = dynamic_cast<innards<MF>*>(m_ptr.get())) {
            return p0->m_mf;
        } else {
            return dynamic_cast<innards<MF&>&>(*m_ptr).m_mf;
        }
    }
 
    template <typename MF>
    [[nodiscard]] MF const& get () const {
        if (auto p0 = dynamic_cast<innards<MF>*>(m_ptr.get())) {
            return p0->m_mf;
        } else if (auto p1 = dynamic_cast<innards<MF&>*>(m_ptr.get())) {
            return p1->m_mf;
        } else {
            return dynamic_cast<innards<MF const&> const&>(*m_ptr).m_mf;
        }
    }
 
    template <typename MF>
    [[nodiscard]] bool is () const { return Type() == typeid(MF); }
 
    [[nodiscard]] bool hasValue () const { return m_ptr != nullptr; }
 
private:
 
 
    struct innards_base // NOLINT(cppcoreguidelines-special-member-functions)
    {
        [[nodiscard]] virtual const std::type_info& Type () const = 0;
        virtual ~innards_base () = default;
    };
 
    template <typename MF>
    struct innards final : innards_base // NOLINT(cppcoreguidelines-special-member-functions)
    {
        innards (MF && mf)
            : m_mf(std::move(mf))
            {}
 
        ~innards () final = default;
 
        [[nodiscard]] const std::type_info& Type () const final {
            return typeid(MF);
        }
 
        MF m_mf;
    };
 
 
    std::unique_ptr<innards_base> m_ptr;
};
 
}
 
#endif