/*
 * Copyright (C) 2020 Belousov Oleg
 *
 * This file is part of PortaPack.
 *
 * 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 2, 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; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street,
 * Boston, MA 02110-1301, USA.
 */

#include "dsp_hilbert.hpp"
#include "dsp_sos_config.hpp"

namespace dsp {

HilbertTransform::HilbertTransform() {
	n = 0;

	sos_i.configure(half_band_lpf_config);
	sos_q.configure(half_band_lpf_config);
}

void HilbertTransform::execute(float in, float &out_i, float &out_q) {
	float a = 0, b = 0;
	
	switch (n) {
		case 0:		a = in;		b = 0;		break;
		case 1:		a = 0;		b = -in;	break;
		case 2:		a = -in;	b = 0;		break;
		case 3:		a = 0;		b = in;		break;
	}
	
	float i = sos_i.execute(a) * 2.0f;
	float q = sos_q.execute(b) * 2.0f;
	
	switch (n) {
		case 0:		out_i = i;	out_q = q;	break;
		case 1:		out_i = -q;	out_q = i;	break;
		case 2:		out_i = -i;	out_q = -q;	break;
		case 3:		out_i = q;	out_q = -i;	break;
	}

	n = (n + 1) % 4;
}

} /* namespace dsp */