delay rds

dsp/delay.c

@@ -1,21 +1,25 @@
+#include <stdlib.h>
+#include <string.h>
 #include "delay.h"
 
-void init_delay_line(delay_line_t *delay_line, uint32_t sample_rate) {
-	delay_line->buffer = malloc(sample_rate * sizeof(float));
-	memset(delay_line->buffer, 0, sample_rate * sizeof(float));
+void init_delay_line(delay_line_t *dl, uint32_t delay_samples) {
+    dl->delay = delay_samples;
+    dl->idx = 0;
+    dl->buffer = calloc(delay_samples, sizeof(float));
 }
 
-void set_delay_line(delay_line_t *delay_line, uint32_t new_delay) {
-	delay_line->delay = new_delay;
+float delay_line(delay_line_t *dl, float in) {
+    float out = dl->buffer[dl->idx];   // read delayed sample
+
+    dl->buffer[dl->idx] = in;          // write new input
+
+    dl->idx++;
+    if (dl->idx >= dl->delay) dl->idx = 0;
+
+    return out;
 }
 
-float delay_line(delay_line_t *delay_line, float in) {
-	delay_line->buffer[delay_line->idx++] = in;
-	if (delay_line->idx >= delay_line->delay) delay_line->idx = 0;
-	return delay_line->buffer[delay_line->idx];
-}
-
-void exit_delay_line(delay_line_t *delay_line) {
-	if(delay_line->buffer != NULL) free(delay_line->buffer);
-	delay_line->buffer = NULL;
+void exit_delay_line(delay_line_t *dl) {
+    if(dl->buffer != NULL) free(dl->buffer);
+    dl->buffer = NULL;
 }