in src/oct.c [139:156]
void OCT_joctet(octet *y,const octet *x)
{
/* y=y || x */
int j;
if (x==NULL) return;
for (int i=0; i<x->len; i++)
{
j=y->len+i;
if (j>=y->max)
{
y->len=y->max;
return;
}
y->val[j]=x->val[i];
}
y->len+=x->len;
}