1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
|
package murmur
const (
c1 int64 = -8663945395140668459 // 0x87c37b91114253d5
c2 int64 = 5545529020109919103 // 0x4cf5ad432745937f
fmix1 int64 = -49064778989728563 // 0xff51afd7ed558ccd
fmix2 int64 = -4265267296055464877 // 0xc4ceb9fe1a85ec53
)
func fmix(n int64) int64 {
// cast to unsigned for logical right bitshift (to match C* MM3 implementation)
n ^= int64(uint64(n) >> 33)
n *= fmix1
n ^= int64(uint64(n) >> 33)
n *= fmix2
n ^= int64(uint64(n) >> 33)
return n
}
func block(p byte) int64 {
return int64(int8(p))
}
func rotl(x int64, r uint8) int64 {
// cast to unsigned for logical right bitshift (to match C* MM3 implementation)
return (x << r) | (int64)((uint64(x) >> (64 - r)))
}
func Murmur3H1(data []byte) int64 {
length := len(data)
var h1, h2, k1, k2 int64
// body
nBlocks := length / 16
for i := 0; i < nBlocks; i++ {
k1, k2 = getBlock(data, i)
k1 *= c1
k1 = rotl(k1, 31)
k1 *= c2
h1 ^= k1
h1 = rotl(h1, 27)
h1 += h2
h1 = h1*5 + 0x52dce729
k2 *= c2
k2 = rotl(k2, 33)
k2 *= c1
h2 ^= k2
h2 = rotl(h2, 31)
h2 += h1
h2 = h2*5 + 0x38495ab5
}
// tail
tail := data[nBlocks*16:]
k1 = 0
k2 = 0
switch length & 15 {
case 15:
k2 ^= block(tail[14]) << 48
fallthrough
case 14:
k2 ^= block(tail[13]) << 40
fallthrough
case 13:
k2 ^= block(tail[12]) << 32
fallthrough
case 12:
k2 ^= block(tail[11]) << 24
fallthrough
case 11:
k2 ^= block(tail[10]) << 16
fallthrough
case 10:
k2 ^= block(tail[9]) << 8
fallthrough
case 9:
k2 ^= block(tail[8])
k2 *= c2
k2 = rotl(k2, 33)
k2 *= c1
h2 ^= k2
fallthrough
case 8:
k1 ^= block(tail[7]) << 56
fallthrough
case 7:
k1 ^= block(tail[6]) << 48
fallthrough
case 6:
k1 ^= block(tail[5]) << 40
fallthrough
case 5:
k1 ^= block(tail[4]) << 32
fallthrough
case 4:
k1 ^= block(tail[3]) << 24
fallthrough
case 3:
k1 ^= block(tail[2]) << 16
fallthrough
case 2:
k1 ^= block(tail[1]) << 8
fallthrough
case 1:
k1 ^= block(tail[0])
k1 *= c1
k1 = rotl(k1, 31)
k1 *= c2
h1 ^= k1
}
h1 ^= int64(length)
h2 ^= int64(length)
h1 += h2
h2 += h1
h1 = fmix(h1)
h2 = fmix(h2)
h1 += h2
// the following is extraneous since h2 is discarded
// h2 += h1
return h1
}
|
