PX4-Autopilot/src/modules/mavlink/mavlink_parameters.cpp

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/**
 * @file mavlink_parameters.cpp
 * Mavlink parameters manager implementation.
 *
 * @author Anton Babushkin <anton.babushkin@me.com>
 */

#include <stdio.h>

#include "mavlink_parameters.h"
#include "mavlink_main.h"

MavlinkParametersManager::MavlinkParametersManager(Mavlink *mavlink) : MavlinkStream(mavlink),
	_send_all_index(-1)
{
}

unsigned
MavlinkParametersManager::get_size()
{
	if (_send_all_index >= 0) {
		return MAVLINK_MSG_ID_PARAM_VALUE_LEN + MAVLINK_NUM_NON_PAYLOAD_BYTES;

	} else {
		return 0;
	}
}

void
MavlinkParametersManager::handle_message(const mavlink_message_t *msg)
{
	switch (msg->msgid) {
	case MAVLINK_MSG_ID_PARAM_REQUEST_LIST: {
			/* request all parameters */
			mavlink_param_request_list_t req_list;
			mavlink_msg_param_request_list_decode(msg, &req_list);

			if (req_list.target_system == mavlink_system.sysid &&
			    (req_list.target_component == mavlink_system.compid || req_list.target_component == MAV_COMP_ID_ALL)) {

				_send_all_index = 0;
				_mavlink->send_statustext_info("[pm] sending list");
			}
			break;
		}

	case MAVLINK_MSG_ID_PARAM_SET: {
			/* set parameter */
			if (msg->msgid == MAVLINK_MSG_ID_PARAM_SET) {
				mavlink_param_set_t set;
				mavlink_msg_param_set_decode(msg, &set);

				if (set.target_system == mavlink_system.sysid &&
				    (set.target_component == mavlink_system.compid || set.target_component == MAV_COMP_ID_ALL)) {

					/* local name buffer to enforce null-terminated string */
					char name[MAVLINK_MSG_PARAM_VALUE_FIELD_PARAM_ID_LEN + 1];
					strncpy(name, set.param_id, MAVLINK_MSG_PARAM_VALUE_FIELD_PARAM_ID_LEN);
					/* enforce null termination */
					name[MAVLINK_MSG_PARAM_VALUE_FIELD_PARAM_ID_LEN] = '\0';
					/* attempt to find parameter, set and send it */
					param_t param = param_find(name);

					if (param == PARAM_INVALID) {
						char buf[MAVLINK_MSG_STATUSTEXT_FIELD_TEXT_LEN];
						sprintf(buf, "[pm] unknown param: %s", name);
						_mavlink->send_statustext_info(buf);

					} else {
						/* set and send parameter */
						param_set(param, &(set.param_value));
						send_param(param);
					}
				}
			}
			break;
		}

	case MAVLINK_MSG_ID_PARAM_REQUEST_READ: {
			/* request one parameter */
			mavlink_param_request_read_t req_read;
			mavlink_msg_param_request_read_decode(msg, &req_read);

			if (req_read.target_system == mavlink_system.sysid &&
			    (req_read.target_component == mavlink_system.compid || req_read.target_component == MAV_COMP_ID_ALL)) {

				/* when no index is given, loop through string ids and compare them */
				if (req_read.param_index < 0) {
					/* local name buffer to enforce null-terminated string */
					char name[MAVLINK_MSG_PARAM_VALUE_FIELD_PARAM_ID_LEN + 1];
					strncpy(name, req_read.param_id, MAVLINK_MSG_PARAM_VALUE_FIELD_PARAM_ID_LEN);
					/* enforce null termination */
					name[MAVLINK_MSG_PARAM_VALUE_FIELD_PARAM_ID_LEN] = '\0';
					/* attempt to find parameter and send it */
					send_param(param_find(name));

				} else {
					/* when index is >= 0, send this parameter again */
					send_param(param_for_index(req_read.param_index));
				}
			}
			break;
		}

	default:
		break;
	}
}

void
MavlinkParametersManager::send(const hrt_abstime t)
{
	/* send all parameters if requested */
	if (_send_all_index >= 0) {
		send_param(param_for_index(_send_all_index));
		_send_all_index++;
		if (_send_all_index >= param_count()) {
			_send_all_index = -1;
		}
	}
}

void
MavlinkParametersManager::send_param(param_t param)
{
	if (param == PARAM_INVALID) {
		return;
	}

	mavlink_param_value_t msg;

	/*
	 * get param value, since MAVLink encodes float and int params in the same
	 * space during transmission, copy param onto float val_buf
	 */
	if (param_get(param, &msg.param_value) != OK) {
		return;
	}

	msg.param_count = param_count();
	msg.param_index = param_get_index(param);

	/* copy parameter name */
	strncpy(msg.param_id, param_name(param), MAVLINK_MSG_PARAM_VALUE_FIELD_PARAM_ID_LEN);

	/* query parameter type */
	param_type_t type = param_type(param);

	/*
	 * Map onboard parameter type to MAVLink type,
	 * endianess matches (both little endian)
	 */
	if (type == PARAM_TYPE_INT32) {
		msg.param_type = MAVLINK_TYPE_INT32_T;

	} else if (type == PARAM_TYPE_FLOAT) {
		msg.param_type = MAVLINK_TYPE_FLOAT;

	} else {
		msg.param_type = MAVLINK_TYPE_FLOAT;
	}

	_mavlink->send_message(MAVLINK_MSG_ID_PARAM_VALUE, &msg);
}