message.hpp

/* This file is part of the "ST" project.
 * You may use, distribute or modify this code under the terms
 * of the GNU General Public License version 2.
 * See LICENCE.txt in the root directory of the project.
 *
 * Author: Maxim Atanasov
 * E-mail: maxim.atanasov@protonmail.com
 */
 
#ifndef ST_MESSAGE_HPP
#define ST_MESSAGE_HPP
 
 
#include <memory>
#include <ST_util/linear_frame_allocator_256.hpp>
 
 
class message {
private:
    static ST::linear_frame_allocator_256<message> allocator;
    std::shared_ptr<void> data; //yes, this holds anything created with make_data<>() AND calls the correct destructor
 
public:
    //An additional 48 bits (3 bytes) of data can be stored here. We're 8 byte aligned, so this is for free.
    uint32_t base_data0 = 0; //additional 32 bits
    uint16_t base_data1 = 0; //additional 16 bits
    uint8_t base_data2 = 0; //additional 8 bits
 
    uint8_t msg_name{};
 
    [[nodiscard]] void *get_data() const;
 
    [[nodiscard]] message *make_copy() const;
 
    message() = default;
 
    explicit message(uint8_t name, const std::shared_ptr<void> &data = nullptr) {
        this->msg_name = name;
        this->data = data;
    }
 
    /*
     * @param name The type of message. See <b>ST::msg_type</b>.
     * @param base_data0 32 bits of data. Use this if you want to avoid creating a shared pointer.
     * @param data The data the message carries - created with <b>make_data<>()</b> or is <b>nullptr</b>
     */
    message(uint8_t name, uint32_t base_data0, const std::shared_ptr<void> &data = nullptr) {
        this->msg_name = name;
        this->base_data0 = base_data0;
        this->data = data;
    }
 
    static void *operator new(size_t) {
        return allocator.allocate();
    }
 
    static void operator delete(void *) {}
 
    ~message() {
        if (data != nullptr) {
            this->data.reset();
        }
    }
 
};
 
static_assert(sizeof(message) == 24, "sizeof message is not 24");
//INLINED METHODS
 
inline void *message::get_data() const {
    return this->data.get();
}
 
inline message *message::make_copy() const {
    return &(*allocator.allocate() = *this);
}
 
#endif //ST_MESSAGE_HPP