Merge branch 'quadrature_encoder' into callable

Author: audiobird

util/quadrature_encoder.hh

@@ -0,0 +1,28 @@
+#pragma once
+
+#include <cstdint>
+
+template<bool invert = false>
+class QuadratureEncoder {
+	static constexpr uint8_t valid_ccw = 0b10000111 ^ (invert ? 0xff : 0x00);
+	static constexpr uint8_t valid_cw = 0b01001011 ^ (invert ? 0xff : 0x00);
+
+	uint8_t prev_state{};
+
+public:
+	enum class State { Undefined, Right, Left };
+
+	State update(bool state_a, bool state_b) {
+		const auto cur_state = state_a | (state_b << 1u);
+		prev_state <<= 2;
+		prev_state |= cur_state;
+		switch (prev_state) {
+			case valid_cw:
+				return State::Right;
+			case valid_ccw:
+				return State::Left;
+			default:
+				return State::Undefined;
+		}
+	}
+};