mirror of https://github.com/gchq/CyberChef.git
79 lines
2.0 KiB
JavaScript
79 lines
2.0 KiB
JavaScript
/**
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* @author mikecat
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* @copyright Crown Copyright 2022
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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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import Utils from "../Utils.mjs";
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import {INPUT_DELIM_OPTIONS} from "../lib/Delim.mjs";
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/**
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* Shuffle operation
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*/
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class Shuffle extends Operation {
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/**
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* Shuffle constructor
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*/
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constructor() {
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super();
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this.name = "Shuffle";
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this.module = "Default";
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this.description = "Randomly reorders input elements.";
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this.infoURL = "https://wikipedia.org/wiki/Shuffling";
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this.inputType = "string";
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this.outputType = "string";
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this.args = [
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{
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name: "Delimiter",
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type: "option",
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value: INPUT_DELIM_OPTIONS
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}
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];
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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 {string}
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*/
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run(input, args) {
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const delim = Utils.charRep(args[0]);
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if (input.length === 0) return input;
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// return a random number in [0, 1)
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const rng = (typeof crypto) !== "undefined" && crypto.getRandomValues ? (function() {
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const buf = new Uint32Array(2);
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return function() {
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// generate 53-bit random integer: 21 + 32 bits
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crypto.getRandomValues(buf);
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const value = (buf[0] >>> (32 - 21)) * ((1 << 30) * 4) + buf[1];
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return value / ((1 << 23) * (1 << 30));
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};
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})() : Math.random;
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// return a random integer in [0, max)
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const randint = function(max) {
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return Math.floor(rng() * max);
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};
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// Split input into shuffleable sections
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const toShuffle = input.split(delim);
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// shuffle elements
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for (let i = toShuffle.length - 1; i > 0; i--) {
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const idx = randint(i + 1);
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const tmp = toShuffle[idx];
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toShuffle[idx] = toShuffle[i];
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toShuffle[i] = tmp;
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}
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return toShuffle.join(delim);
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}
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}
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export default Shuffle;
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