Simple int32 hash with relatively good avalance

gistfile1.c

/* it has avalance ~ 33.3 measured by http://baagoe.org/en/w/index.php/Avalanche_on_integer_hash_functions */
/* it is not the best, but i think it is good enough */
uint32_t hash(uint32_t n) {
  n ^= n >> 16;
  n *= 0xd5b25599;
  return n + (n >> 16);
}