Refactor bit pattern matching.

Remove AccessCodeCorrelator, Unstuff classes.

firmware/common/bit_pattern.hpp

@@ -0,0 +1,74 @@
+/*
+ * 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 __BIT_PATTERN_H__
+#define __BIT_PATTERN_H__
+
+#include <cstdint>
+#include <cstddef>
+
+class BitPattern {
+public:
+	constexpr BitPattern(
+		const uint32_t code,
+		const size_t code_length,
+		const size_t maximum_hanning_distance = 0
+	) : code_ { code },
+		mask_ { (1UL << code_length) - 1UL },
+		maximum_hanning_distance_ { maximum_hanning_distance }
+	{
+	}
+
+	uint32_t code() const {
+		return code_;
+	}
+
+	uint32_t mask() const {
+		return mask_;
+	}
+
+	size_t maximum_hanning_distance() const {
+		return maximum_hanning_distance_;
+	}
+
+private:
+	uint32_t code_;
+	uint32_t mask_;
+	size_t maximum_hanning_distance_;
+};
+
+class BitHistory {
+public:
+	void add(const uint_fast8_t bit) {
+		history = (history << 1) | (bit & 1);
+	}
+
+	bool matches(const BitPattern& pattern) const {
+		const auto delta_bits = (history ^ pattern.code()) & pattern.mask();
+		const size_t count = __builtin_popcountl(delta_bits);
+		return (count <= pattern.maximum_hanning_distance());
+	}
+
+private:
+	uint32_t history { 0 };
+};
+
+#endif/*__BIT_PATTERN_H__*/