msgbuffer.h

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/*
 * Copyright 2014 Vladimir Ermakov.
 *
 * 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 3 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, write to the Free Software Foundation, Inc.,
 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#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