extract_port_from_str
int port = extract_port_from_str(str, num);
int high = extract_port_from_str(mid+1, num);
low = extract_port_from_str(buf, num);
int port = extract_port_from_str(str, num);
int high = extract_port_from_str(mid+1, num);
low = extract_port_from_str(buf, num);