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