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package fnv1a
const (
// FNV-1a
offset32 = uint32(2166136261)
prime32 = uint32(16777619)
// Init32 is what 32 bits hash values should be initialized with.
Init32 = offset32
)
// HashString32 returns the hash of s.
func HashString32(s string) uint32 {
return AddString32(Init32, s)
}
// HashBytes32 returns the hash of u.
func HashBytes32(b []byte) uint32 {
return AddBytes32(Init32, b)
}
// HashUint32 returns the hash of u.
func HashUint32(u uint32) uint32 {
return AddUint32(Init32, u)
}
// AddString32 adds the hash of s to the precomputed hash value h.
func AddString32(h uint32, s string) uint32 {
for len(s) >= 8 {
h = (h ^ uint32(s[0])) * prime32
h = (h ^ uint32(s[1])) * prime32
h = (h ^ uint32(s[2])) * prime32
h = (h ^ uint32(s[3])) * prime32
h = (h ^ uint32(s[4])) * prime32
h = (h ^ uint32(s[5])) * prime32
h = (h ^ uint32(s[6])) * prime32
h = (h ^ uint32(s[7])) * prime32
s = s[8:]
}
if len(s) >= 4 {
h = (h ^ uint32(s[0])) * prime32
h = (h ^ uint32(s[1])) * prime32
h = (h ^ uint32(s[2])) * prime32
h = (h ^ uint32(s[3])) * prime32
s = s[4:]
}
if len(s) >= 2 {
h = (h ^ uint32(s[0])) * prime32
h = (h ^ uint32(s[1])) * prime32
s = s[2:]
}
if len(s) > 0 {
h = (h ^ uint32(s[0])) * prime32
}
return h
}
// AddBytes32 adds the hash of b to the precomputed hash value h.
func AddBytes32(h uint32, b []byte) uint32 {
for len(b) >= 8 {
h = (h ^ uint32(b[0])) * prime32
h = (h ^ uint32(b[1])) * prime32
h = (h ^ uint32(b[2])) * prime32
h = (h ^ uint32(b[3])) * prime32
h = (h ^ uint32(b[4])) * prime32
h = (h ^ uint32(b[5])) * prime32
h = (h ^ uint32(b[6])) * prime32
h = (h ^ uint32(b[7])) * prime32
b = b[8:]
}
if len(b) >= 4 {
h = (h ^ uint32(b[0])) * prime32
h = (h ^ uint32(b[1])) * prime32
h = (h ^ uint32(b[2])) * prime32
h = (h ^ uint32(b[3])) * prime32
b = b[4:]
}
if len(b) >= 2 {
h = (h ^ uint32(b[0])) * prime32
h = (h ^ uint32(b[1])) * prime32
b = b[2:]
}
if len(b) > 0 {
h = (h ^ uint32(b[0])) * prime32
}
return h
}
// AddUint32 adds the hash value of the 8 bytes of u to h.
func AddUint32(h, u uint32) uint32 {
h = (h ^ ((u >> 24) & 0xFF)) * prime32
h = (h ^ ((u >> 16) & 0xFF)) * prime32
h = (h ^ ((u >> 8) & 0xFF)) * prime32
h = (h ^ ((u >> 0) & 0xFF)) * prime32
return h
}
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