moved ddc to own files

Makefile

@@ -22,5 +22,5 @@ clean:
 
 encode: encode.o mmap_file.o
 
-decode: decode.o mmap_file.o pcm.o wav.o alsa.o window.o
+decode: decode.o mmap_file.o pcm.o wav.o alsa.o window.o ddc.o
 

ddc.c

@@ -0,0 +1,77 @@
+
+#include <math.h>
+#include <stdlib.h>
+#include <complex.h> 
+#include "window.h"
+#include "ddc.h"
+
+void do_ddc(ddc_t *ddc, float *input, float complex *output)
+{
+	int in = 0;
+	ddc->s[ddc->last] = input[in++];
+	ddc->last = (ddc->last + 1) < ddc->samples ? ddc->last + 1 : 0;
+	ddc->skip += ddc->L;
+	// this works only for L <= M
+	for (int k = 0; k < ddc->L; k++) {
+		float complex sum = 0.0;
+		for (int i = ddc->offset, j = ddc->last; i < ddc->taps; i += ddc->L) {
+			sum += ddc->b[i] * ddc->s[j];
+			j += j ? - 1 : ddc->samples - 1;
+		}
+
+		ddc->offset = (ddc->offset + ddc->M) % ddc->L;
+
+		while (ddc->skip < ddc->M) {
+			ddc->s[ddc->last] = input[in++];
+			ddc->last = (ddc->last + 1) < ddc->samples ? ddc->last + 1 : 0;
+			ddc->skip += ddc->L;
+		}
+
+		ddc->skip %= ddc->M;
+		output[k] = ddc->osc * sum;
+		ddc->osc *= ddc->d;
+//		ddc->osc /= cabsf(ddc->osc); // not really needed
+	}
+}
+ddc_t *alloc_ddc(float freq, float bw, float step, int taps, int L, int M, float (*window)(float, float))
+{
+	float lstep = step / (float)L;
+	float ostep = step * (float)M / (float)L;
+	ddc_t *ddc = malloc(sizeof(ddc_t));
+	ddc->taps = taps;
+	ddc->samples = (taps + L - 1) / L;
+	ddc->b = malloc(sizeof(float complex) * ddc->taps);
+	ddc->s = malloc(sizeof(float) * ddc->samples);
+	ddc->osc = I;
+	ddc->d = cexpf(-I * 2.0 * M_PI * freq * ostep);
+	ddc->offset = 0;
+	ddc->last = 0;
+	ddc->skip = 0;
+	ddc->L = L;
+	ddc->M = M;
+	for (int i = 0; i < ddc->samples; i++)
+		ddc->s[i] = 0.0;
+	float sum = 0.0;
+	for (int i = 0; i < ddc->taps; i++) {
+		float N = (float)ddc->taps;
+		float n = (float)i;
+		float x = n - (N - 1.0) / 2.0;
+		float l = 2.0 * M_PI * bw * lstep;
+		float w = window(n, ddc->taps);
+		float h = 0.0 == x ? l / M_PI : sinf(l * x) / (x * M_PI);
+		float b = w * h;
+		sum += b;
+		complex float o = cexpf(I * 2.0 * M_PI * freq * lstep * n);
+		ddc->b[i] = b * o * (float)L;
+	}
+	for (int i = 0; i < ddc->taps; i++)
+		ddc->b[i] /= sum;
+	return ddc;
+}
+void free_ddc(ddc_t *ddc)
+{
+	free(ddc->b);
+	free(ddc->s);
+	free(ddc);
+}
+

ddc.h

@@ -0,0 +1,25 @@
+
+#ifndef DDC_H
+#define DDC_H
+#include "window.h"
+
+typedef struct {
+	float complex *b;
+	float *s;
+	float complex osc;
+	float complex d;
+	int offset;
+	int skip;
+	int last;
+	int taps;
+	int samples;
+	int L;
+	int M;
+} ddc_t;
+
+void do_ddc(ddc_t *, float *, float complex *);
+ddc_t *alloc_ddc(float, float, float, int, int, int, float (*)(float, float));
+void free_ddc(ddc_t *);
+
+#endif
+

decode.c

@@ -8,7 +8,7 @@
 #include <time.h>
 #include "mmap_file.h"
 #include "pcm.h"
-#include "window.h"
+#include "ddc.h"
 
 float lerp(float a, float b, float x)
 {
@@ -31,90 +31,6 @@ float limit(float min, float max, float x)
 	return tmp > max ? max : tmp;
 }
 
-typedef struct {
-	float complex *b;
-	float *s;
-	float complex osc;
-	float complex d;
-	int offset;
-	int skip;
-	int last;
-	int taps;
-	int samples;
-	int L;
-	int M;
-} ddc_t;
-
-void do_ddc(ddc_t *ddc, float *input, float complex *output)
-{
-	int in = 0;
-	ddc->s[ddc->last] = input[in++];
-	ddc->last = (ddc->last + 1) < ddc->samples ? ddc->last + 1 : 0;
-	ddc->skip += ddc->L;
-	// this works only for L <= M
-	for (int k = 0; k < ddc->L; k++) {
-		float complex sum = 0.0;
-		for (int i = ddc->offset, j = ddc->last; i < ddc->taps; i += ddc->L) {
-			sum += ddc->b[i] * ddc->s[j];
-			j += j ? - 1 : ddc->samples - 1;
-		}
-
-		ddc->offset = (ddc->offset + ddc->M) % ddc->L;
-
-		while (ddc->skip < ddc->M) {
-			ddc->s[ddc->last] = input[in++];
-			ddc->last = (ddc->last + 1) < ddc->samples ? ddc->last + 1 : 0;
-			ddc->skip += ddc->L;
-		}
-
-		ddc->skip %= ddc->M;
-		output[k] = ddc->osc * sum;
-		ddc->osc *= ddc->d;
-//		ddc->osc /= cabsf(ddc->osc); // not really needed
-	}
-}
-ddc_t *alloc_ddc(float freq, float bw, float step, int taps, int L, int M, float (*window)(float, float))
-{
-	float lstep = step / (float)L;
-	float ostep = step * (float)M / (float)L;
-	ddc_t *ddc = malloc(sizeof(ddc_t));
-	ddc->taps = taps;
-	ddc->samples = (taps + L - 1) / L;
-	ddc->b = malloc(sizeof(float complex) * ddc->taps);
-	ddc->s = malloc(sizeof(float) * ddc->samples);
-	ddc->osc = I;
-	ddc->d = cexpf(-I * 2.0 * M_PI * freq * ostep);
-	ddc->offset = 0;
-	ddc->last = 0;
-	ddc->skip = 0;
-	ddc->L = L;
-	ddc->M = M;
-	for (int i = 0; i < ddc->samples; i++)
-		ddc->s[i] = 0.0;
-	float sum = 0.0;
-	for (int i = 0; i < ddc->taps; i++) {
-		float N = (float)ddc->taps;
-		float n = (float)i;
-		float x = n - (N - 1.0) / 2.0;
-		float l = 2.0 * M_PI * bw * lstep;
-		float w = window(n, ddc->taps);
-		float h = 0.0 == x ? l / M_PI : sinf(l * x) / (x * M_PI);
-		float b = w * h;
-		sum += b;
-		complex float o = cexpf(I * 2.0 * M_PI * freq * lstep * n);
-		ddc->b[i] = b * o * (float)L;
-	}
-	for (int i = 0; i < ddc->taps; i++)
-		ddc->b[i] /= sum;
-	return ddc;
-}
-void free_ddc(ddc_t *ddc)
-{
-	free(ddc->b);
-	free(ddc->s);
-	free(ddc);
-}
-
 typedef struct {
 	float *s;
 	int last;