static void filter(priv_t * p)
{
int i, num_in = max(0, fifo_occupancy(&p->input_fifo));
filter_t const * f = p->filter_ptr;
int const overlap = f->num_taps - 1;
double * output;
while (num_in >= f->dft_length) {
double const * input = fifo_read_ptr(&p->input_fifo);
fifo_read(&p->input_fifo, f->dft_length - overlap, NULL);
num_in -= f->dft_length - overlap;
output = fifo_reserve(&p->output_fifo, f->dft_length);
fifo_trim_by(&p->output_fifo, overlap);
memcpy(output, input, f->dft_length * sizeof(*output));
lsx_safe_rdft(f->dft_length, 1, output);
output[0] *= f->coefs[0];
output[1] *= f->coefs[1];
for (i = 2; i < f->dft_length; i += 2) {
double tmp = output[i];
output[i ] = f->coefs[i ] * tmp - f->coefs[i+1] * output[i+1];
output[i+1] = f->coefs[i+1] * tmp + f->coefs[i ] * output[i+1];
}
lsx_safe_rdft(f->dft_length, -1, output);
}
}
void lsx_set_dft_filter(dft_filter_t *f, double *h, int n, int post_peak)
{
int i;
f->num_taps = n;
f->post_peak = post_peak;
f->dft_length = lsx_set_dft_length(f->num_taps);
f->coefs = lsx_calloc(f->dft_length, sizeof(*f->coefs));
for (i = 0; i < f->num_taps; ++i)
f->coefs[(i + f->dft_length - f->num_taps + 1) & (f->dft_length - 1)] = h[i] / f->dft_length * 2;
lsx_safe_rdft(f->dft_length, 1, f->coefs);
free(h);
}
