// Return true iff "enough" elements are equal to (i+value)%256 between buf[start] and buf[stop-1].
static int check_enough(const uint8_t* buf, size_t start, size_t stop, uint8_t value)
{
// Return true iff "enough" elements are equal to (i+value)%256 between buf[start] and buf[stop-1].
static int check_enough(const uint8_t* buf, size_t start, size_t stop, uint8_t value)
{