void pwl__fetch(register pwl_susp_type susp, snd_list_type snd_list)
{
int cnt = 0; /* how many samples computed */
int togo;
int n;
sample_block_type out;
register sample_block_values_type out_ptr;
register sample_block_values_type out_ptr_reg;
register double incr_reg;
register double lvl_reg;
falloc_sample_block(out, "pwl__fetch");
out_ptr = out->samples;
snd_list->block = out;
while (cnt < max_sample_block_len) { /* outer loop */
/* first compute how many samples to generate in inner loop: */
/* don't overflow the output sample block: */
togo = max_sample_block_len - cnt;
if (susp->bpt_ptr == NULL) {
out:
togo = 0; /* indicate termination */
break; /* we're done */
}
{ long cur = susp->susp.current + cnt;
long nn = getfixnum(car(susp->bpt_ptr)) - cur;
if (nn == 0) {
if (compute_lvl(susp) || compute_incr(susp, &nn, cur)) goto out;
}
togo = MIN(nn, togo);
}
n = togo;
incr_reg = susp->incr;
lvl_reg = susp->lvl;
out_ptr_reg = out_ptr;
if (n) do { /* the inner sample computation loop */
*out_ptr_reg++ = (sample_type) lvl_reg;
lvl_reg += incr_reg;;
} while (--n); /* inner loop */
susp->lvl += susp->incr * togo;
out_ptr += togo;
cnt += togo;
} /* outer loop */
/* test for termination */
if (togo == 0 && cnt == 0) {
snd_list_terminate(snd_list);
} else {
snd_list->block_len = cnt;
susp->susp.current += cnt;
}
} /* pwl__fetch */
/*
* returns true if it is time to terminate
*/
boolean compute_incr(pwl_susp_type susp, long *n, long cur)
{
double target;
while (*n == 0) {
*n = getfixnum(car(susp->bpt_ptr)) - cur;
/* if there is a 2nd element of the pair, get the target */
if (cdr(susp->bpt_ptr))
target = getflonum(car(cdr(susp->bpt_ptr)));
else target = 0.0;
if (*n > 0) susp->incr = (target - susp->lvl) / *n;
else if (compute_lvl(susp)) return true;
}
return false;
}
