domotz-remote-pawn/src/utils/random.js

Domotz Agent

/**
 * This file is part of Domotz Agent.
 * Copyright (C) 2016  Domotz Ltd
 *
 * Domotz Agent is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Domotz Agent is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Domotz Agent.  If not, see <http://www.gnu.org/licenses/>.
 *
 * Created by Tommaso Latini <tommaso@domotz.com> on 28/12/15.
 */

const MODULE = 'RANDOM';

var crypto = require('crypto');

function md5(data) {
    return crypto.createHash('md5').update(data).digest('hex');
}

function getRandomBytes(n, encoding) {
    var randomStr;
    var rnd = crypto.randomBytes(n);
    randomStr = rnd.toString(encoding);
    return randomStr;
}

function randomNumberFromString(str, start, end) {
    var currentVal,
        res = start,
        range = end - start + 1,
        input = md5(str);

    for (var i = 0; range >= 1.0; i++) {
        currentVal = parseInt(input.charAt(i), 16);
        range = range / 16.0;
        res += currentVal * range;
    }

    return Math.round(res);
}

module.exports = {
    md5: md5,
    getRandomBytes: getRandomBytes,
    randomNumberFromString: randomNumberFromString,
};