Class array_storage

include/msd/storage.hpp:127–176

 */
template <typename T, std::size_t N>
class array_storage {
   public:
    static_assert(N > 0, "Capacity must be greater than zero.");

    /**
     * @brief The storage capacity.
     *
     * @attention Required for static storage.
     */
    static constexpr std::size_t capacity = N;

    /**
     * @brief Adds an element to the back of the array.
     *
     * @tparam Type Type of the element to insert.
     * @param value The value to insert (perfect forwarded).
     * @warning It's undefined behaviour to push into a full array.
     */
    template <typename Type>
    void push_back(Type&& value)
    {
        array_[(front_ + size_) % N] = std::forward<Type>(value);
        ++size_;
    }

    /**
     * @brief Marks the front element as removed and moves it to the output.
     *
     * @param out Reference to the variable where the front element will be moved.
     * @warning It's undefined behaviour to pop from an empty array.
     */
    void pop_front(T& out)
    {
        out = std::move(array_[front_]);
        front_ = (front_ + 1) % N;
        --size_;
    }

    /**
     * @brief Returns the number of elements currently stored.
     *
     * @return Current size.
     */
    NODISCARD std::size_t size() const noexcept { return size_; }

   private:
    std::array<T, N> array_{};
    std::size_t size_{0};
    std::size_t front_{0};
};

template <typename T, std::size_t N>
constexpr std::size_t array_storage<T, N>::capacity;