mirror of https://github.com/gchq/CyberChef.git
140 lines
4.1 KiB
JavaScript
140 lines
4.1 KiB
JavaScript
/**
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* Based on murmurhash-js (https://github.com/garycourt/murmurhash-js)
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* @author Gary Court
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* @license MIT
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*
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* @author AliceGrey [alice@grey.systems]
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* @copyright Crown Copyright 2024
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* @license Apache-2.0
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*/
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import Operation from "../Operation.mjs";
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/**
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* MurmurHash3 operation
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*/
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class MurmurHash3 extends Operation {
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/**
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* MurmurHash3 constructor
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*/
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constructor() {
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super();
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this.name = "MurmurHash3";
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this.module = "Hashing";
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this.description = "Generates a MurmurHash v3 for a string input and an optional seed input";
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this.infoURL = "https://wikipedia.org/wiki/MurmurHash";
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this.inputType = "string";
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this.outputType = "number";
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this.args = [
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{
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name: "Seed",
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type: "number",
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value: 0
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},
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{
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name: "Convert to Signed",
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type: "boolean",
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value: false
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}
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];
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}
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/**
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* Calculates the MurmurHash3 hash of the input.
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* Based on Gary Court's JS MurmurHash implementation
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* @see http://github.com/garycourt/murmurhash-js
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* @author AliceGrey [alice@grey.systems]
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* @param {string} input ASCII only
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* @param {number} seed Positive integer only
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* @return {number} 32-bit positive integer hash
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*/
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mmh3(input, seed) {
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let h1b;
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let k1;
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const remainder = input.length & 3; // input.length % 4
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const bytes = input.length - remainder;
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let h1 = seed;
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const c1 = 0xcc9e2d51;
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const c2 = 0x1b873593;
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let i = 0;
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while (i < bytes) {
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k1 =
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((input.charCodeAt(i) & 0xff)) |
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((input.charCodeAt(++i) & 0xff) << 8) |
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((input.charCodeAt(++i) & 0xff) << 16) |
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((input.charCodeAt(++i) & 0xff) << 24);
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++i;
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k1 = ((((k1 & 0xffff) * c1) + ((((k1 >>> 16) * c1) & 0xffff) << 16))) & 0xffffffff;
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k1 = (k1 << 15) | (k1 >>> 17);
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k1 = ((((k1 & 0xffff) * c2) + ((((k1 >>> 16) * c2) & 0xffff) << 16))) & 0xffffffff;
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h1 ^= k1;
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h1 = (h1 << 13) | (h1 >>> 19);
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h1b = ((((h1 & 0xffff) * 5) + ((((h1 >>> 16) * 5) & 0xffff) << 16))) & 0xffffffff;
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h1 = (((h1b & 0xffff) + 0x6b64) + ((((h1b >>> 16) + 0xe654) & 0xffff) << 16));
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}
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k1 = 0;
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if (remainder === 3) {
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k1 ^= (input.charCodeAt(i + 2) & 0xff) << 16;
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}
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if (remainder === 3 || remainder === 2) {
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k1 ^= (input.charCodeAt(i + 1) & 0xff) << 8;
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}
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if (remainder === 3 || remainder === 2 || remainder === 1) {
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k1 ^= (input.charCodeAt(i) & 0xff);
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k1 = (((k1 & 0xffff) * c1) + ((((k1 >>> 16) * c1) & 0xffff) << 16)) & 0xffffffff;
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k1 = (k1 << 15) | (k1 >>> 17);
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k1 = (((k1 & 0xffff) * c2) + ((((k1 >>> 16) * c2) & 0xffff) << 16)) & 0xffffffff;
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h1 ^= k1;
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}
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h1 ^= input.length;
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h1 ^= h1 >>> 16;
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h1 = (((h1 & 0xffff) * 0x85ebca6b) + ((((h1 >>> 16) * 0x85ebca6b) & 0xffff) << 16)) & 0xffffffff;
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h1 ^= h1 >>> 13;
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h1 = ((((h1 & 0xffff) * 0xc2b2ae35) + ((((h1 >>> 16) * 0xc2b2ae35) & 0xffff) << 16))) & 0xffffffff;
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h1 ^= h1 >>> 16;
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return h1 >>> 0;
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}
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/**
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* Converts an unsigned 32-bit integer to a signed 32-bit integer
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* @author AliceGrey [alice@grey.systems]
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* @param {value} 32-bit unsigned integer
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* @return {number} 32-bit signed integer
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*/
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unsignedToSigned(value) {
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return value & 0x80000000 ? -0x100000000 + value : value;
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}
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/**
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* @param {string} input
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* @param {Object[]} args
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* @returns {number}
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*/
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run(input, args) {
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if (args && args.length >= 1) {
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const seed = args[0];
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const hash = this.mmh3(input, seed);
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if (args.length > 1 && args[1]) {
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return this.unsignedToSigned(hash);
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}
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return hash;
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}
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return this.mmh3(input);
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}
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}
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export default MurmurHash3;
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