Move IIR struct and configs to common/.

firmware/common/dsp_iir.hpp

@@ -0,0 +1,70 @@
+/*
+ * Copyright (C) 2015 Jared Boone, ShareBrained Technology, Inc.
+ *
+ * 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.
+ */
+
+#ifndef __DSP_IIR_H__
+#define __DSP_IIR_H__
+
+#include <array>
+
+#include "dsp_types.hpp"
+
+struct iir_biquad_config_t {
+	std::array<float, 3> b;
+	std::array<float, 3> a;
+};
+
+constexpr iir_biquad_config_t iir_config_passthrough {
+	{ { 1.0f, 0.0f, 0.0f } },
+	{ { 0.0f, 0.0f, 0.0f } },
+};
+
+constexpr iir_biquad_config_t iir_config_no_pass {
+	{ { 0.0f, 0.0f, 0.0f } },
+	{ { 0.0f, 0.0f, 0.0f } },
+};
+
+class IIRBiquadFilter {
+public:
+	// http://www.musicdsp.org/files/Audio-EQ-Cookbook.txt
+	constexpr IIRBiquadFilter(
+	) : IIRBiquadFilter(iir_config_no_pass)
+	{
+	}
+
+	// Assume all coefficients are normalized so that a0=1.0
+	constexpr IIRBiquadFilter(
+		const iir_biquad_config_t& config
+	) : config(config)
+	{
+	}
+
+	void configure(const iir_biquad_config_t& new_config);
+
+	void execute(const buffer_f32_t& buffer_in, const buffer_f32_t& buffer_out);
+	void execute_in_place(const buffer_f32_t& buffer);
+
+private:
+	iir_biquad_config_t config;
+	std::array<float, 3> x { { 0.0f, 0.0f, 0.0f } };
+	std::array<float, 3> y { { 0.0f, 0.0f, 0.0f } };
+};
+
+#endif/*__DSP_IIR_H__*/