Packet.hpp

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// MAVLink router and firewall.
// Copyright (C) 2018  Michael R. Shannon <mrshannon.aerospace@gmail.com>
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.


#ifndef PACKET_HPP_
#define PACKET_HPP_


#include <cstdint>
#include <memory>
#include <optional>
#include <ostream>
#include <string>
#include <vector>

#include "MAVAddress.hpp"


class Connection;


/** A MAVLink packet.
 *
 *  This is an abstract class, it is meant to be overridden by classes
 *  implementing either version 1 or version 2 of the MAVLink packet wire
 *  protocol.
 *
 *  \internal The \ref Version enum must be changed if another packet version is
 *      added.
 */
class Packet
{
    public:
        enum Version
        {
            V1 = 0x0100,  //!< MAVLink Version 1.0
            V2 = 0x0200   //!< MAVLink Version 2.0
        };

        /** Copy constructor.
         *
         *  \param other Packet to copy from.
         */
        Packet(const Packet &other) = default;
        /** Move constructor.
         *
         *  \param other Packet to move from.
         */
        Packet(Packet &&other) = default;
        Packet(std::vector<uint8_t> data);
        virtual ~Packet();  // Clang does not like pure virtual destructors.
        /** Return packet version.
         *
         *  \returns Two byte Packet version with major version in MSB and minor
         *      version in LSB.
         */
        virtual Version version() const = 0;
        /** Return MAVLink message ID.
         *
         *  \returns The numeric message ID of the MAVLink packet (0 to 255).
         */
        virtual unsigned long id() const = 0;
        /** Return MAVLink message name.
         *
         *  \returns The message name of the MAVLink packet.
         */
        virtual std::string name() const = 0;
        /** Return source address.
         *
         *  Where the packet came from.
         *
         *  \returns The source MAVLink address of the packet.
         */
        virtual MAVAddress source() const = 0;
        /** Return destination address.
         *
         *  Where the packet is sent to.  This is optional because not all
         *  packets have a destination.   %If a system is specified, but not a
         *  component, a component ID of 0 will be used (the broadcast ID).
         *
         *  \returns The destination MAVLink address of the packet if not a
         *      broadcast packet.  %If the packet does not have a destination
         *      address then {} will be returned.
         */
        virtual std::optional<MAVAddress> dest() const = 0;
        void connection(std::weak_ptr<Connection> connection);
        const std::shared_ptr<Connection> connection() const;
        const std::vector<uint8_t> &data() const;
        /** Assignment operator.
         *
         *  \param other Packet to copy from.
         */
        Packet &operator=(const Packet &other) = default;
        /** Assignment operator (by move semantics).
         *
         *  \param other Packet to move from.
         */
        Packet &operator=(Packet &&other) = default;

    private:
        std::vector<uint8_t> data_;
        std::weak_ptr<Connection> connection_;
};


bool operator==(const Packet &lhs, const Packet &rhs);
bool operator!=(const Packet &lhs, const Packet &rhs);
std::ostream &operator<<(std::ostream &os, const Packet &packet);


#endif // PACKET_HPP_