worked on FIR-Convolution and LocalMaxima detection

math/LocalMaxima.h

@@ -0,0 +1,64 @@
+#ifndef LOCALMAXIMA_H
+#define LOCALMAXIMA_H
+
+class LocalMaxima {
+
+	static constexpr float MAX = 1e40;
+
+	size_t everyNth;
+
+	size_t cnt = 0;
+	float s0;
+	float s1;		// center value
+	float s2;
+
+
+public:
+
+	struct Res {
+		bool isMax;
+		float val;
+		Res(bool isMax, float val) : isMax(isMax), val(val) {;}
+	};
+
+	/** ctor. use only every n-th sample */
+	LocalMaxima(const size_t everyNth) : everyNth(everyNth) {
+		reset();
+	}
+
+	/** is the given value a local maxima? */
+	Res add(const float s) {
+
+		if		(cnt == 0*everyNth) {s0 = s;}	// set, wait some time
+		else if (cnt == 1*everyNth) {s1 = s;}	// set, wait some time
+		else if (cnt == 2*everyNth) {s2 = s;}	// set
+		else if (cnt  > 2*everyNth) {			// now shift values for every time step, until max is found
+			s0 = s1;
+			s1 = s2;
+			s2 = s;
+		}
+
+		++cnt;
+
+		if ((s1 > s0) && (s1 > s2)) {
+			Res res(true, s1);
+			reset();
+			return res;
+		}
+
+		return Res(false, 0);
+
+	}
+
+private:
+
+	void reset() {
+		s0 = MAX;
+		s1 = MAX;
+		s2 = MAX;
+		cnt = 0;
+	}
+
+};
+
+#endif // LOCALMAXIMA_H