1 files changed, 99 insertions, 0 deletions
diff --git a/fourier.c b/fourier.c
new file mode 100644
index 0000000..def5c13
--- /dev/null
+++ b/fourier.c
@@ -0,0 +1,99 @@
+#include <complex.h>
+#include <math.h>
+#include <sys/param.h> // MIN/MAX
+#include <stdio.h> // debug only
+#include "frekvence.h"
+#define SAMPLES 256
+#define FREKVENC (sizeof frekvence/sizeof frekvence[0])
+struct fourier {
+	void (* callback)(struct fourier *);
+	enum ton trenutni;
+	enum ton zadnji_klican;
+	unsigned count;
+	double samples[SAMPLES];
+	unsigned sample;
+	complex sums[FREKVENC];
+	double rate;
+	unsigned minimal_duration;
+#ifdef USERDATA
+	USERDATA
+#else
+	void * userdata;
+#endif
+};
+void add_sample (struct fourier * f, double received) {
+	for (unsigned frekvenca = 0; frekvenca < FREKVENC; frekvenca++) {
+		f->sums[frekvenca] += received*cpow(M_E, -2*M_PI*I*frekvence[frekvenca]*f->sample/f->rate);
+		f->sums[frekvenca] -= f->samples[f->sample % SAMPLES]*cpow(M_E, -2*M_PI*I*frekvence[frekvenca]*(f->sample-SAMPLES)/f->rate);
+	}
+	int najv[3] = { 0 };
+	double val[3] = { 0 };
+	for (unsigned i = 0; i < FREKVENC; i++)
+		for (int j = 0; j < 3; j++) {
+			double iabs = cabs(f->sums[i]);
+			if (iabs > val[j]) {
+				for (int k = 2; k > j; k--) {
+					najv[k] = najv[k-1];
+					val[k] = val[k-1];
+				}
+				najv[j] = i;
+				val[j] = iabs;
+				break;
+			}
+		}
+	enum ton trenutni = ni;
+	if (val[1] > val[0]/3 && val[2] < val[1]/3) {
+		int večja = MAX(frekvence[najv[0]], frekvence[najv[1]]);
+		int manjša = MIN(frekvence[najv[0]], frekvence[najv[1]]);
+		enum ton znaki[4][4] =
+			{{dtmf_1, dtmf_2, dtmf_3, dtmf_a},
+			{dtmf_4, dtmf_5, dtmf_6, dtmf_b},
+			{dtmf_7, dtmf_8, dtmf_9, dtmf_c},
+			{dtmf_zvezdica, dtmf_0, dtmf_lojtra, dtmf_d}};
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wpedantic"
+		int getidx (int freq) {
+			for (int i = 0; i < 8; i++)
+				if (freq == frekvence[i])
+					return i%4;
+			return -1;
+		}
+#pragma GCC diagnostic pop
+		if (getidx(manjša) == -1 || getidx(večja) == -1)
+			trenutni = ni;
+		else
+			trenutni = znaki[getidx(manjša)][getidx(večja)];
+	}
+	if (val[1] < val[0]/3 && najv[0] > 7)
+		trenutni = band+najv[0]-band_tipka;
+	if (trenutni == f->trenutni) {
+		if (f->count++ == f->minimal_duration && f->zadnji_klican != f->trenutni) {
+			f->zadnji_klican = f->trenutni;
+			f->callback(f);
+		}
+	} else {
+		f->count = 0;
+		f->trenutni = trenutni;
+	}
+	f->samples[f->sample++ % SAMPLES] = received;
+}
+#if __INCLUDE_LEVEL__ == 0
+#include <stdio.h>
+#include <string.h>
+void callback (struct fourier * f) {
+	printf("%s\n", toni[f->trenutni]);
+}
+int main (void) {
+	struct fourier f;
+	memset(&f, 0, sizeof f);
+	f.callback = callback;
+	f.minimal_duration = SAMPLES;
+	f.rate = 8000;
+	int received = 0;
+	while ((received = getchar()) != EOF) {
+		unsigned char intermed = received;
+		char recvd = *(char *) &intermed;
+		add_sample(&f, recvd);
+	}
+}
+#endif