mirror of https://github.com/gchq/CyberChef.git
93 lines
2.4 KiB
JavaScript
93 lines
2.4 KiB
JavaScript
/**
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* @author d98762625 [d98762625@gmail.com]
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* @copyright Crown Copyright 2018
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* @license Apache-2.0
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*/
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import Operation from "../Operation";
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/**
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* Power Set operation
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*/
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class PowerSet extends Operation {
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/**
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* Power set constructor
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*/
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constructor() {
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super();
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this.name = "Power Set";
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this.module = "Default";
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this.description = "Calculates all the subsets of a set.";
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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: "Item delimiter",
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type: "binaryString",
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value: ","
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},
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];
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}
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/**
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* Generate the power set
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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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[this.itemDelimiter] = args;
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// Split and filter empty strings
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const inputArray = input.split(this.itemDelimiter).filter(a => a);
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if (inputArray.length) {
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return this.runPowerSet(inputArray);
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}
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return "";
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}
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/**
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* Return the power set of the inputted set.
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*
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* @param {Object[]} a
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* @returns {Object[]}
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*/
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runPowerSet(a) {
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// empty array items getting picked up
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a = a.filter(i => i.length);
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if (!a.length) {
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return [];
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}
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/**
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* Decimal to binary function
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* @param {*} dec
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*/
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const toBinary = (dec) => (dec >>> 0).toString(2);
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const result = new Set();
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// Get the decimal number to make a binary as long as the input
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const maxBinaryValue = parseInt(Number(a.map(i => "1").reduce((p, c) => p + c)), 2);
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// Make an array of each binary number from 0 to maximum
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const binaries = [...Array(maxBinaryValue + 1).keys()]
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.map(toBinary)
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.map(i => i.padStart(toBinary(maxBinaryValue).length, "0"));
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// XOR the input with each binary to get each unique permutation
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binaries.forEach((binary) => {
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const split = binary.split("");
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result.add(a.filter((item, index) => split[index] === "1"));
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});
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// map for formatting & put in length order.
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return [...result]
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.map(r => r.join(this.itemDelimiter)).sort((a, b) => a.length - b.length)
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.map(i => `${i}\n`).join("");
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}
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}
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export default PowerSet;
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