blob: e63146a2b7e70b6e270fb277fb933b1657669ab8 (
plain)
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
136
137
138
|
/**
* @preserve
* JS Implementation of incremental MurmurHash3 (r150) (as of May 10, 2013)
*
* @author <a href="mailto:jensyt@gmail.com">Jens Taylor</a>
* @see http://github.com/homebrewing/brauhaus-diff
* @author <a href="mailto:gary.court@gmail.com">Gary Court</a>
* @see http://github.com/garycourt/murmurhash-js
* @author <a href="mailto:aappleby@gmail.com">Austin Appleby</a>
* @see http://sites.google.com/site/murmurhash/
*/
(function(){
var cache;
// Call this function without `new` to use the cached object (good for
// single-threaded environments), or with `new` to create a new object.
//
// @param {string} key A UTF-16 or ASCII string
// @param {number} seed An optional positive integer
// @return {object} A MurmurHash3 object for incremental hashing
function MurmurHash3(key, seed) {
var m = this instanceof MurmurHash3 ? this : cache;
m.reset(seed)
if (typeof key === 'string' && key.length > 0) {
m.hash(key);
}
if (m !== this) {
return m;
}
};
// Incrementally add a string to this hash
//
// @param {string} key A UTF-16 or ASCII string
// @return {object} this
MurmurHash3.prototype.hash = function(key) {
var h1, k1, i, top, len;
len = key.length;
this.len += len;
k1 = this.k1;
i = 0;
switch (this.rem) {
case 0: k1 ^= len > i ? (key.charCodeAt(i++) & 0xffff) : 0;
case 1: k1 ^= len > i ? (key.charCodeAt(i++) & 0xffff) << 8 : 0;
case 2: k1 ^= len > i ? (key.charCodeAt(i++) & 0xffff) << 16 : 0;
case 3:
k1 ^= len > i ? (key.charCodeAt(i) & 0xff) << 24 : 0;
k1 ^= len > i ? (key.charCodeAt(i++) & 0xff00) >> 8 : 0;
}
this.rem = (len + this.rem) & 3; // & 3 is same as % 4
len -= this.rem;
if (len > 0) {
h1 = this.h1;
while (1) {
k1 = (k1 * 0x2d51 + (k1 & 0xffff) * 0xcc9e0000) & 0xffffffff;
k1 = (k1 << 15) | (k1 >>> 17);
k1 = (k1 * 0x3593 + (k1 & 0xffff) * 0x1b870000) & 0xffffffff;
h1 ^= k1;
h1 = (h1 << 13) | (h1 >>> 19);
h1 = (h1 * 5 + 0xe6546b64) & 0xffffffff;
if (i >= len) {
break;
}
k1 = ((key.charCodeAt(i++) & 0xffff)) ^
((key.charCodeAt(i++) & 0xffff) << 8) ^
((key.charCodeAt(i++) & 0xffff) << 16);
top = key.charCodeAt(i++);
k1 ^= ((top & 0xff) << 24) ^
((top & 0xff00) >> 8);
}
k1 = 0;
switch (this.rem) {
case 3: k1 ^= (key.charCodeAt(i + 2) & 0xffff) << 16;
case 2: k1 ^= (key.charCodeAt(i + 1) & 0xffff) << 8;
case 1: k1 ^= (key.charCodeAt(i) & 0xffff);
}
this.h1 = h1;
}
this.k1 = k1;
return this;
};
// Get the result of this hash
//
// @return {number} The 32-bit hash
MurmurHash3.prototype.result = function() {
var k1, h1;
k1 = this.k1;
h1 = this.h1;
if (k1 > 0) {
k1 = (k1 * 0x2d51 + (k1 & 0xffff) * 0xcc9e0000) & 0xffffffff;
k1 = (k1 << 15) | (k1 >>> 17);
k1 = (k1 * 0x3593 + (k1 & 0xffff) * 0x1b870000) & 0xffffffff;
h1 ^= k1;
}
h1 ^= this.len;
h1 ^= h1 >>> 16;
h1 = (h1 * 0xca6b + (h1 & 0xffff) * 0x85eb0000) & 0xffffffff;
h1 ^= h1 >>> 13;
h1 = (h1 * 0xae35 + (h1 & 0xffff) * 0xc2b20000) & 0xffffffff;
h1 ^= h1 >>> 16;
return h1 >>> 0;
};
// Reset the hash object for reuse
//
// @param {number} seed An optional positive integer
MurmurHash3.prototype.reset = function(seed) {
this.h1 = typeof seed === 'number' ? seed : 0;
this.rem = this.k1 = this.len = 0;
return this;
};
// A cached object to use. This can be safely used if you're in a single-
// threaded environment, otherwise you need to create new hashes to use.
cache = new MurmurHash3();
if (typeof(module) != 'undefined') {
module.exports = MurmurHash3;
} else {
this.MurmurHash3 = MurmurHash3;
}
}());
|
