/*
	This file is part of EqualizerAPO, a system-wide equalizer.
	Copyright (C) 2013  Jonas Thedering

	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 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.,
	51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/

#include <string>

#define IS_DENORMAL(f) (((*(unsigned int *)&(f))&0x7f800000) == 0)

class BiQuad
{
public:
	enum Type
	{
		LOW_PASS, HIGH_PASS, BAND_PASS, NOTCH, ALL_PASS, PEAKING, LOW_SHELF, HIGH_SHELF
	};

	BiQuad() {}
	BiQuad(Type type, float dbGain, float freq, float srate, float bandwidthOrQOrS, bool isBandwidth);

	__forceinline
	void removeDenormals()
	{
		if(IS_DENORMAL(x1))
			x1 = 0.0f;
		if(IS_DENORMAL(x2))
			x2 = 0.0f;
		if(IS_DENORMAL(y1))
			y1 = 0.0f;
		if(IS_DENORMAL(y2))
			y2 = 0.0f;
	}

	__forceinline
	float process(float sample)
	{
		float result = a0 * sample + a[0] * x1 + a[1] * x2 +
			a[2] * y1 + a[3] * y2;

		x2 = x1;
		x1 = sample;

		y2 = y1;
		y1 = result;

		//Input for next stage
		return result;
	}

	float gainAt(float freq, float srate);

private:
	__declspec(align(16)) float a[4];
	float a0;

	float x1, x2;
	float y1, y2;
};