PX4-Autopilot/src/modules/systemlib/mixer/mixer_group.cpp

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/**
 * @file mixer_group.cpp
 *
 * Mixer collection.
 */

#include <px4_config.h>

#include <sys/types.h>
#include <stdint.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <poll.h>
#include <errno.h>
#include <stdio.h>
#include <math.h>
#include <unistd.h>

#include "mixer.h"

#define debug(fmt, args...)	do { } while(0)
//#define debug(fmt, args...)	do { printf("[mixer] " fmt "\n", ##args); } while(0)
//#include <debug.h>
//#define debug(fmt, args...)	syslog(fmt "\n", ##args)

MixerGroup::MixerGroup(ControlCallback control_cb, uintptr_t cb_handle) :
	Mixer(control_cb, cb_handle),
	_first(nullptr)
{
}

MixerGroup::~MixerGroup()
{
	reset();
}

void
MixerGroup::add_mixer(Mixer *mixer)
{
	Mixer **mpp;

	mpp = &_first;

	while (*mpp != nullptr) {
		mpp = &((*mpp)->_next);
	}

	*mpp = mixer;
	mixer->_next = nullptr;
}

void
MixerGroup::reset()
{
	Mixer *mixer;
	Mixer *next = _first;

	/* flag mixer as invalid */
	_first = nullptr;

	/* discard sub-mixers */
	while (next != nullptr) {
		mixer = next;
		next = mixer->_next;
		delete mixer;
		mixer = nullptr;
	}
}

unsigned
MixerGroup::mix(float *outputs, unsigned space, uint16_t *status_reg)
{
	Mixer	*mixer = _first;
	unsigned index = 0;

	while ((mixer != nullptr) && (index < space)) {
		index += mixer->mix(outputs + index, space - index, status_reg);
		mixer = mixer->_next;
	}

	return index;
}

/*
 * set_trims() has no effect except for the SimpleMixer implementation for which set_trim()
 * always returns the value one.
 * The only other existing implementation is MultirotorMixer, which ignores the trim value
 * and returns _rotor_count.
 */
unsigned
MixerGroup::set_trims(int16_t *values, unsigned n)
{
	Mixer	*mixer = _first;
	unsigned index = 0;

	while ((mixer != nullptr) && (index < n)) {
		/* convert from integer to float */
		float offset = (float)values[index] / 10000;

		/* to be safe, clamp offset to range of [-100, 100] usec */
		if (offset < -0.2f) { offset = -0.2f; }

		if (offset >  0.2f) { offset =  0.2f; }

		debug("set trim: %d, offset: %5.3f", values[index], (double)offset);
		index += mixer->set_trim(offset);
		mixer = mixer->_next;
	}

	return index;
}

void
MixerGroup::set_thrust_factor(float val)
{
	Mixer	*mixer = _first;

	while (mixer != nullptr) {
		mixer->set_thrust_factor(val);
		mixer = mixer->_next;
	}

}

uint16_t
MixerGroup::get_saturation_status()
{
	Mixer	*mixer = _first;
	uint16_t sat = 0;

	while (mixer != nullptr) {
		sat |= mixer->get_saturation_status();
		mixer = mixer->_next;
	}

	return sat;
}

unsigned
MixerGroup::count()
{
	Mixer	*mixer = _first;
	unsigned index = 0;

	while (mixer != nullptr) {
		mixer = mixer->_next;
		index++;
	}

	return index;
}

void
MixerGroup::groups_required(uint32_t &groups)
{
	Mixer	*mixer = _first;

	while (mixer != nullptr) {
		mixer->groups_required(groups);
		mixer = mixer->_next;
	}
}

int
MixerGroup::load_from_buf(const char *buf, unsigned &buflen)
{
	int ret = -1;
	const char *end = buf + buflen;

	/*
	 * Loop until either we have emptied the buffer, or we have failed to
	 * allocate something when we expected to.
	 */
	while (buflen > 0) {
		Mixer *m = nullptr;
		const char *p = end - buflen;
		unsigned resid = buflen;

		/*
		 * Use the next character as a hint to decide which mixer class to construct.
		 */
		switch (*p) {
		case 'Z':
			m = NullMixer::from_text(p, resid);
			break;

		case 'M':
			m = SimpleMixer::from_text(_control_cb, _cb_handle, p, resid);
			break;

		case 'R':
			m = MultirotorMixer::from_text(_control_cb, _cb_handle, p, resid);
			break;

		case 'H':
			m = HelicopterMixer::from_text(_control_cb, _cb_handle, p, resid);
			break;

		default:
			/* it's probably junk or whitespace, skip a byte and retry */
			buflen--;
			continue;
		}

		/*
		 * If we constructed something, add it to the group.
		 */
		if (m != nullptr) {
			add_mixer(m);

			/* we constructed something */
			ret = 0;

			/* only adjust buflen if parsing was successful */
			buflen = resid;
			debug("SUCCESS - buflen: %d", buflen);

		} else {

			/*
			 * There is data in the buffer that we expected to parse, but it didn't,
			 * so give up for now.
			 */
			break;
		}
	}

	/* nothing more in the buffer for us now */
	return ret;
}

void MixerGroup::set_max_delta_out_once(float delta_out_max)
{
	Mixer	*mixer = _first;

	while (mixer != nullptr) {
		mixer->set_max_delta_out_once(delta_out_max);
		mixer = mixer->_next;
	}
}