source: trip-planner-front/node_modules/imurmurhash/imurmurhash.js@ 6a3a178

Last change on this file since 6a3a178 was 6a3a178, checked in by Ema <ema_spirova@…>, 3 years ago

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1/**
2 * @preserve
3 * JS Implementation of incremental MurmurHash3 (r150) (as of May 10, 2013)
4 *
5 * @author <a href="mailto:jensyt@gmail.com">Jens Taylor</a>
6 * @see http://github.com/homebrewing/brauhaus-diff
7 * @author <a href="mailto:gary.court@gmail.com">Gary Court</a>
8 * @see http://github.com/garycourt/murmurhash-js
9 * @author <a href="mailto:aappleby@gmail.com">Austin Appleby</a>
10 * @see http://sites.google.com/site/murmurhash/
11 */
12(function(){
13 var cache;
14
15 // Call this function without `new` to use the cached object (good for
16 // single-threaded environments), or with `new` to create a new object.
17 //
18 // @param {string} key A UTF-16 or ASCII string
19 // @param {number} seed An optional positive integer
20 // @return {object} A MurmurHash3 object for incremental hashing
21 function MurmurHash3(key, seed) {
22 var m = this instanceof MurmurHash3 ? this : cache;
23 m.reset(seed)
24 if (typeof key === 'string' && key.length > 0) {
25 m.hash(key);
26 }
27
28 if (m !== this) {
29 return m;
30 }
31 };
32
33 // Incrementally add a string to this hash
34 //
35 // @param {string} key A UTF-16 or ASCII string
36 // @return {object} this
37 MurmurHash3.prototype.hash = function(key) {
38 var h1, k1, i, top, len;
39
40 len = key.length;
41 this.len += len;
42
43 k1 = this.k1;
44 i = 0;
45 switch (this.rem) {
46 case 0: k1 ^= len > i ? (key.charCodeAt(i++) & 0xffff) : 0;
47 case 1: k1 ^= len > i ? (key.charCodeAt(i++) & 0xffff) << 8 : 0;
48 case 2: k1 ^= len > i ? (key.charCodeAt(i++) & 0xffff) << 16 : 0;
49 case 3:
50 k1 ^= len > i ? (key.charCodeAt(i) & 0xff) << 24 : 0;
51 k1 ^= len > i ? (key.charCodeAt(i++) & 0xff00) >> 8 : 0;
52 }
53
54 this.rem = (len + this.rem) & 3; // & 3 is same as % 4
55 len -= this.rem;
56 if (len > 0) {
57 h1 = this.h1;
58 while (1) {
59 k1 = (k1 * 0x2d51 + (k1 & 0xffff) * 0xcc9e0000) & 0xffffffff;
60 k1 = (k1 << 15) | (k1 >>> 17);
61 k1 = (k1 * 0x3593 + (k1 & 0xffff) * 0x1b870000) & 0xffffffff;
62
63 h1 ^= k1;
64 h1 = (h1 << 13) | (h1 >>> 19);
65 h1 = (h1 * 5 + 0xe6546b64) & 0xffffffff;
66
67 if (i >= len) {
68 break;
69 }
70
71 k1 = ((key.charCodeAt(i++) & 0xffff)) ^
72 ((key.charCodeAt(i++) & 0xffff) << 8) ^
73 ((key.charCodeAt(i++) & 0xffff) << 16);
74 top = key.charCodeAt(i++);
75 k1 ^= ((top & 0xff) << 24) ^
76 ((top & 0xff00) >> 8);
77 }
78
79 k1 = 0;
80 switch (this.rem) {
81 case 3: k1 ^= (key.charCodeAt(i + 2) & 0xffff) << 16;
82 case 2: k1 ^= (key.charCodeAt(i + 1) & 0xffff) << 8;
83 case 1: k1 ^= (key.charCodeAt(i) & 0xffff);
84 }
85
86 this.h1 = h1;
87 }
88
89 this.k1 = k1;
90 return this;
91 };
92
93 // Get the result of this hash
94 //
95 // @return {number} The 32-bit hash
96 MurmurHash3.prototype.result = function() {
97 var k1, h1;
98
99 k1 = this.k1;
100 h1 = this.h1;
101
102 if (k1 > 0) {
103 k1 = (k1 * 0x2d51 + (k1 & 0xffff) * 0xcc9e0000) & 0xffffffff;
104 k1 = (k1 << 15) | (k1 >>> 17);
105 k1 = (k1 * 0x3593 + (k1 & 0xffff) * 0x1b870000) & 0xffffffff;
106 h1 ^= k1;
107 }
108
109 h1 ^= this.len;
110
111 h1 ^= h1 >>> 16;
112 h1 = (h1 * 0xca6b + (h1 & 0xffff) * 0x85eb0000) & 0xffffffff;
113 h1 ^= h1 >>> 13;
114 h1 = (h1 * 0xae35 + (h1 & 0xffff) * 0xc2b20000) & 0xffffffff;
115 h1 ^= h1 >>> 16;
116
117 return h1 >>> 0;
118 };
119
120 // Reset the hash object for reuse
121 //
122 // @param {number} seed An optional positive integer
123 MurmurHash3.prototype.reset = function(seed) {
124 this.h1 = typeof seed === 'number' ? seed : 0;
125 this.rem = this.k1 = this.len = 0;
126 return this;
127 };
128
129 // A cached object to use. This can be safely used if you're in a single-
130 // threaded environment, otherwise you need to create new hashes to use.
131 cache = new MurmurHash3();
132
133 if (typeof(module) != 'undefined') {
134 module.exports = MurmurHash3;
135 } else {
136 this.MurmurHash3 = MurmurHash3;
137 }
138}());
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