Function hash4

s2/encode_better.go:16–19

hash4 returns the hash of the lowest 4 bytes of u to fit in a hash table with h bits. Preferably h should be a constant and should always be <32.

(u uint64, h uint8)

// hash4 returns the hash of the lowest 4 bytes of u to fit in a hash table with h bits.
// Preferably h should be a constant and should always be <32.
func hash4(u uint64, h uint8) uint32 {
	const prime4bytes = 2654435761
	return (uint32(u) * prime4bytes) >> ((32 - h) & 31)
}

// hash5 returns the hash of the lowest 5 bytes of u to fit in a hash table with h bits.
// Preferably h should be a constant and should always be <64.