Initial firmware commit.

firmware/baseband/block_decimator.hpp

@@ -0,0 +1,90 @@
+/*
+ * 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 __BLOCK_DECIMATOR_H__
+#define __BLOCK_DECIMATOR_H__
+
+#include <cstdint>
+#include <cstddef>
+
+#include "complex.hpp"
+
+template<size_t N>
+class BlockDecimator {
+public:
+	constexpr BlockDecimator(
+		const size_t factor
+	) : factor { factor }
+	{
+	}
+
+	void set_input_sampling_rate(const uint32_t new_sampling_rate) {
+		if( new_sampling_rate != input_sampling_rate ) {
+			input_sampling_rate = new_sampling_rate;
+			reset_state();
+		}
+	}
+
+	void set_factor(const size_t new_factor) {
+		if( new_factor != factor ) {
+			factor = new_factor;
+			reset_state();
+		}
+	}
+
+	uint32_t output_sampling_rate() const {
+		return input_sampling_rate / factor;
+	}
+
+	template<typename BlockCallback>
+	void feed(const buffer_c16_t src, BlockCallback callback) {
+		/* NOTE: Input block size must be >= factor */
+
+		set_input_sampling_rate(src.sampling_rate);
+
+		while( src_i < src.count ) {
+			buffer[dst_i++] = src.p[src_i];
+			if( dst_i == buffer.size() ) {
+				callback({ buffer.data(), buffer.size(), output_sampling_rate() });
+				reset_state();
+				dst_i = 0;
+			}
+
+			src_i += factor;
+		}
+
+		src_i -= src.count;
+	}
+
+private:
+	std::array<complex16_t, N> buffer;
+	uint32_t input_sampling_rate { 0 };
+	size_t factor { 1 };
+	size_t src_i { 0 };
+	size_t dst_i { 0 };
+
+	void reset_state() {
+		src_i = 0;
+		dst_i = 0;
+	}
+};
+
+#endif/*__BLOCK_DECIMATOR_H__*/