VILLASnode/lib/hooks/scale.cpp

/** Scale hook.
 *
 * @author Steffen Vogel <post@steffenvogel.de>
 * @copyright 2014-2022, Institute for Automation of Complex Power Systems, EONERC
 * @license Apache 2.0
 *********************************************************************************/

#include <cstring>

#include <villas/hook.hpp>
#include <villas/sample.hpp>

namespace villas {
namespace node {

class ScaleHook : public MultiSignalHook {

protected:
	double scale;
	double offset;

public:
	ScaleHook(Path *p, Node *n, int fl, int prio, bool en = true) :
		MultiSignalHook(p, n, fl, prio, en),
		scale(1.0),
		offset(0.0)
	{ }

	virtual void parse(json_t *json)
	{
		int ret;
		json_error_t err;

		assert(state != State::STARTED);

		MultiSignalHook::parse(json);

		ret = json_unpack_ex(json, &err, 0, "{ s?: F, s?: F }",
			"scale", &scale,
			"offset", &offset
		);
		if (ret)
			throw ConfigError(json, err, "node-config-hook-scale");

		state = State::PARSED;
	}

	virtual Hook::Reason process(struct Sample *smp)
	{
		for (auto index : signalIndices) {
			assert(index < smp->length);
			assert(state == State::STARTED);

			switch (sample_format(smp, index)) {
				case SignalType::INTEGER:
					smp->data[index].i *= scale;
					smp->data[index].i += offset;
					break;

				case SignalType::FLOAT:
					smp->data[index].f *= scale;
					smp->data[index].f += offset;
					break;

				case SignalType::COMPLEX:
					smp->data[index].z *= scale;
					smp->data[index].z += offset;
					break;

				default: { }
			}
		}

		return Reason::OK;
	}
};

/* Register hook */
static char n[] = "scale";
static char d[] = "Scale signals by a factor and add offset";
static HookPlugin<ScaleHook, n, d, (int) Hook::Flags::PATH | (int) Hook::Flags::NODE_READ | (int) Hook::Flags::NODE_WRITE> p;

} /* namespace node */
} /* namespace villas */