CyberChef/src/core/operations/baseClasses/Arithmetic.mjs

/**
 * @author d98762625 [d98762625@gmailcom]
 * @copyright Crown Copyright 2018
 * @license Apache-2.0
 */

import Utils from "../../Utils";
import BigNumber from "bignumber.js";

/**
 * 
 */
class Arithmetic {

    /**
     * @constant
     * @default
     */
    static get DELIM_OPTIONS() {
        return ["Line feed", "Space", "Comma", "Semi-colon", "Colon", "CRLF"];
    }

    /**
     * Converts a string array to a number array.
     *
     * @private
     * @param {string[]} input
     * @param {string} delim
     * @returns {BigNumber[]}
     */
    static _createNumArray(input, delim) {
        delim = Utils.charRep(delim || "Space");
        const splitNumbers = input.split(delim);
        const numbers = [];
        let num;

        splitNumbers.map((number) => {
            try {
                num = BigNumber(number.trim());
                if (!num.isNaN()) {
                    numbers.push(num);
                }
            } catch (err) {
                // This line is not a valid number
            }
        });
        return numbers;
    }


    /**
     * Adds an array of numbers and returns the value.
     *
     * @private
     * @param {BigNumber[]} data
     * @returns {BigNumber}
     */
    static _sum(data) {
        if (data.length > 0) {
            return data.reduce((acc, curr) => acc.plus(curr));
        }
    }


    /**
     * Subtracts an array of numbers and returns the value.
     *
     * @private
     * @param {BigNumber[]} data
     * @returns {BigNumber}
     */
    static _sub(data) {
        if (data.length > 0) {
            return data.reduce((acc, curr) => acc.minus(curr));
        }
    }


    /**
     * Multiplies an array of numbers and returns the value.
     *
     * @private
     * @param {BigNumber[]} data
     * @returns {BigNumber}
     */
    static _multi(data) {
        if (data.length > 0) {
            return data.reduce((acc, curr) => acc.times(curr));
        }
    }


    /**
     * Divides an array of numbers and returns the value.
     *
     * @private
     * @param {BigNumber[]} data
     * @returns {BigNumber}
     */
    static _div(data) {
        if (data.length > 0) {
            return data.reduce((acc, curr) => acc.div(curr));
        }
    }


    /**
     * Computes mean of a number array and returns the value.
     *
     * @private
     * @param {BigNumber[]} data
     * @returns {BigNumber}
     */
    static _mean(data) {
        if (data.length > 0) {
            return Arithmetic._sum(data).div(data.length);
        }
    }


    /**
     * Computes median of a number array and returns the value.
     *
     * @private
     * @param {BigNumber[]} data
     * @returns {BigNumber}
     */
    static _median(data) {
        if ((data.length % 2) === 0 && data.length > 0) {
            data.sort(function(a, b){
                return a.minus(b);
            });
            const first = data[Math.floor(data.length / 2)];
            const second = data[Math.floor(data.length / 2) - 1];
            return Arithmetic._mean([first, second]);
        } else {
            return data[Math.floor(data.length / 2)];
        }
    }


    /**
     * Computes standard deviation of a number array and returns the value.
     *
     * @private
     * @param {BigNumber[]} data
     * @returns {BigNumber}
     */
    static _stdDev(data) {
        if (data.length > 0) {
            const avg = Arithmetic._mean(data);
            let devSum = new BigNumber(0);
            data.map((datum) => {
                devSum = devSum.plus(datum.minus(avg).pow(2));
            });
            return devSum.div(data.length).sqrt();
        }
    }
}

export default Arithmetic;