mirror of https://github.com/gchq/CyberChef.git
54 lines
1.1 KiB
JavaScript
54 lines
1.1 KiB
JavaScript
/**
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* @author n1474335 [n1474335@gmail.com]
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* @copyright Crown Copyright 2017
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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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* Chi Square operation
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*/
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class ChiSquare extends Operation {
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/**
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* ChiSquare constructor
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*/
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constructor() {
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super();
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this.name = "Chi Square";
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this.module = "Default";
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this.description = "Calculates the Chi Square distribution of values.";
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this.inputType = "ArrayBuffer";
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this.outputType = "number";
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this.args = [];
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}
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/**
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* @param {ArrayBuffer} 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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const data = new Uint8Array(input);
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const distArray = new Array(256).fill(0);
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let total = 0;
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for (let i = 0; i < data.length; i++) {
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distArray[data[i]]++;
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}
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for (let i = 0; i < distArray.length; i++) {
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if (distArray[i] > 0) {
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total += Math.pow(distArray[i] - data.length / 256, 2) / (data.length / 256);
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}
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}
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return total;
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}
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}
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export default ChiSquare;
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