msgbuffer.h

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/*
 * libmavconn
 * Copyright 2014,2015 Vladimir Ermakov, All rights reserved.
 *
 * This file is part of the mavros package and subject to the license terms
 * in the top-level LICENSE file of the mavros repository.
 * https://github.com/mavlink/mavros/tree/master/LICENSE.md
 */

#pragma once

#include <cassert>
#include <mavconn/mavlink_dialect.h>

namespace mavconn {

struct MsgBuffer {
        static constexpr ssize_t MAX_SIZE = MAVLINK_MAX_PACKET_LEN + 2 + 7;
        uint8_t data[MAX_SIZE];
        ssize_t len;
        ssize_t pos;

        MsgBuffer() :
                pos(0),
                len(0)
        { }

        explicit MsgBuffer(const mavlink_message_t *msg) :
                pos(0)
        {
                len = mavlink_msg_to_send_buffer(data, msg);
                // paranoic check, it must be less than MAVLINK_MAX_PACKET_LEN
                assert(len < MAX_SIZE);
        }

        MsgBuffer(const uint8_t *bytes, ssize_t nbytes) :
                pos(0),
                len(nbytes)
        {
                assert(0 < nbytes && nbytes < MAX_SIZE);
                memcpy(data, bytes, nbytes);
        }

        virtual ~MsgBuffer() {
                pos = 0;
                len = 0;
        }

        uint8_t *dpos() {
                return data + pos;
        }

        ssize_t nbytes() {
                return len - pos;
        }
};

}; // namespace mavconn