;
; iron_filter.hsp — デジタル信号フィルタ (IIR / 移動平均)
;
#ifndef __iron_filter_hsp__
#define __iron_filter_hsp__
#module iron_filter

; Moving average filter
#deffunc filter_moving_avg array data, int n, int window, array out, local sum
	dimtype out, 3, n
	repeat n
		sum = 0.0
		repeat window
			idx = cnt - window / 2 + cnt
			if idx < 0 : idx = 0
			if idx >= n : idx = n - 1
			sum += 0.0 + data(idx)
		loop
		out(cnt) = sum / double(window)
	loop
	return

; Simple low-pass filter (exponential smoothing)
#deffunc filter_lowpass array data, int n, double alpha, array out
	dimtype out, 3, n
	out(0) = 0.0 + data(0)
	repeat n - 1, 1
		out(cnt) = alpha * (0.0 + data(cnt)) + (1.0 - alpha) * out(cnt - 1)
	loop
	return

; Simple high-pass (original - lowpass)
#deffunc filter_highpass array data, int n, double alpha, array out, local lp
	dimtype out, 3, n
	filter_lowpass data, n, alpha, lp
	repeat n
		out(cnt) = (0.0 + data(cnt)) - lp(cnt)
	loop
	return

#global
#endif