dlib C++ Library - any.h

    // Copyright (C) 2010  Davis E. King (davis@dlib.net)
    // License: Boost Software License   See LICENSE.txt for the full license.
    #ifndef DLIB_AnY_H_
    #define DLIB_AnY_H_

    #include "any_abstract.h"
    #include <memory>
    #include "storage.h"

    namespace dlib
    {
    // ----------------------------------------------------------------------------------------

        class any
        {
        public:
            any()                               = default;
            any(const any& other)               = default;
            any& operator=(const any& other)    = default;
            any(any&& other)                    = default;
            any& operator=(any&& other)         = default;

            template<
                typename T,
                std::enable_if_t<!std::is_same<std::decay_t<T>, any>::value, bool> = true
            >
            any(T&& item)
            : storage{std::forward<T>(item)}
            {
            }

            template<
                typename T,
                typename T_ = std::decay_t<T>,
                std::enable_if_t<!std::is_same<T_, any>::value, bool> = true
            >
            any& operator=(T&& item)
            {
                if (contains<T_>())
                    storage.unsafe_get<T_>() = std::forward<T>(item);
                else
                    *this = std::move(any{std::forward<T>(item)});
                return *this;
            }

            bool is_empty() const { return storage.is_empty(); }
            void clear()          { storage.clear(); }
            void swap (any& item) { std::swap(*this, item); }

            template<typename T>      bool contains() const { return storage.contains<T>();}
            template <typename T>       T& cast_to()        { return storage.cast_to<T>(); }
            template <typename T> const T& cast_to() const  { return storage.cast_to<T>(); }
            template <typename T>       T& get()            { return storage.get<T>(); }

        private:
            te::storage_heap storage;
        };

    // ----------------------------------------------------------------------------------------

        template <typename T> T& any_cast(any& a) { return a.cast_to<T>(); }
        template <typename T> const T& any_cast(const any& a) { return a.cast_to<T>(); }

    // ----------------------------------------------------------------------------------------

    }

    #endif // DLIB_AnY_H_