// Set the elements between buf[start] and buf[stop-1] to (i+value)%256
static void set(uint8_t *buf, size_t start, size_t stop, uint8_t value) {
for(size_t i = start; i < stop; i++) {
// Set the elements between buf[start] and buf[stop-1] to (i+value)%256
static void set(uint8_t *buf, size_t start, size_t stop, uint8_t value) {
for(size_t i = start; i < stop; i++) {