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#include <stdio.h>
#include <assert.h>
#include <string.h>
#include <math.h>
#include <inttypes.h>
#include "resample.h"
#include "interpol.h"
#define SINC_RADIUS 10
struct resample_state {
float delta;
int sfreq, dfreq;
struct interpol_state interpol;
};
static int lcd(int a, int b) {
assert(a >= 1 && b >= 1);
while (a != b) {
while (a > b) {
a = a-b;
}
while (b > a) {
b = b-a;
}
}
return a;
}
void resample_init(struct resample_state *s) {
assert(s);
memset(s, 0, sizeof(struct resample_state));
s->sfreq = s->dfreq = -1;
}
void resample_done(struct resample_state *s) {
assert(s);
interpol_done(&s->interpol);
}
void resample_get(struct resample_state *s, float* sp, int *sl, float *dp, int *dl, int sfreq, int dfreq) {
int di;
float x = 0;
assert(s && sp && dp && sfreq > 0 && dfreq > 0);
assert(*sl > 0);
assert(*dl > 0);
if (sfreq != s->sfreq || dfreq != s->dfreq) {
interpol_done(&s->interpol);
interpol_init(&s->interpol, dfreq/lcd(sfreq,dfreq), SINC_RADIUS);
s->sfreq = sfreq;
s->dfreq = dfreq;
}
di = 0;
while (di < *dl) {
x = (float) di*sfreq/dfreq + s->delta;
if (x + SINC_RADIUS + 1 > *sl)
break;
*(dp++) = interpol_get(&s->interpol, sp, *sl, x);
di++;
}
*dl = di;
if (x >= SINC_RADIUS) {
*sl = (int) (x - SINC_RADIUS);
s->delta = x - *sl;
} else
*sl = 0;
}
#if (TEST == 7)
#define BUFSIZE (10*1024)
void sinbuf(float *buf, int l) {
static int i = 0;
for (; l > 0; l--, i = (i+1 == 100) ? 0 : i+1)
*(buf++) = sin(i*2*M_PI/100);
}
void convbuf(float *buf, int l) {
int16_t *p = (int16_t*) buf;
for (; l > 0; l--, p+=2) {
float v = ((float) *p + (float) *(p+1))/0x7FFF;
*(buf++) = (v < -1) ? -1 : ((v > 1) ? 1 : v);
}
}
int main(int argc, char *argv[]) {
struct resample_state resample;
float inbuf[BUFSIZE];
int total_n_inbuf = 0;
if (argc > 1) {
stdin = fopen(argv[1], "r");
assert(stdin);
}
resample_init(&resample);
while (!feof(stdin)) {
float outbuf[BUFSIZE];
int n_outbuf = sizeof(outbuf) / sizeof(float);
int n_inbuf, c;
fprintf(stderr, "LOOP!\n");
c = fread(inbuf + total_n_inbuf, sizeof(float), sizeof(inbuf)/sizeof(float) - total_n_inbuf, stdin);
convbuf(inbuf + total_n_inbuf, c);
n_inbuf = (total_n_inbuf += c);
/* sinbuf(inbuf + total_n_inbuf, sizeof(inbuf)/sizeof(float) - total_n_inbuf); */
/* n_inbuf = total_n_inbuf = sizeof(inbuf)/sizeof(float); *\/ */
resample_get(&resample, inbuf, &n_inbuf, outbuf, &n_outbuf, 44100, 8000);
fwrite(outbuf, sizeof(float), n_outbuf, stdout);
if (n_inbuf) {
total_n_inbuf -= n_inbuf;
memmove(inbuf, inbuf + n_inbuf, total_n_inbuf*sizeof(float));
}
}
resample_done(&resample);
return 0;
}
#endif
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