70 lines
1.9 KiB
JavaScript
70 lines
1.9 KiB
JavaScript
/**
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* Copyright 2013-2018 Zaid Abdulla
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*
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* This file is part of GenieACS.
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*
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* GenieACS is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as
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* published by the Free Software Foundation, either version 3 of the
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* License, or (at your option) any later version.
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*
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* GenieACS is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with GenieACS. If not, see <http://www.gnu.org/licenses/>.
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*/
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"use strict";
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const crypto = require("crypto");
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const later = require("later");
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function md532(str) {
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const digest = crypto
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.createHash("md5")
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.update(str)
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.digest();
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return (
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digest.readUInt32LE(0) ^
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digest.readUInt32LE(4) ^
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digest.readUInt32LE(8) ^
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digest.readUInt32LE(12)
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);
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}
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function variance(deviceId, vrnc) {
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return (md532(deviceId) >>> 0) % vrnc;
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}
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function interval(timestamp, intrvl, offset = 0) {
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return Math.trunc((timestamp + offset) / intrvl) * intrvl - offset;
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}
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function parseCron(cronExp) {
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const parts = cronExp.trim().split(/\s+/);
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if (parts.length === 5) parts.unshift("*");
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return later.schedule(later.parse.cron(parts.join(" "), true));
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}
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function cron(timestamp, schedule, offset = 0) {
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// TODO later.js doesn't throw erorr if expression is invalid!
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const ret = [0, 0];
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const prev = schedule.prev(1, new Date(timestamp + offset));
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if (prev) ret[0] = prev.setMilliseconds(0) - offset;
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const next = schedule.next(1, new Date(timestamp + offset + 1000));
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if (next) ret[1] = next.setMilliseconds(0) - offset;
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return ret;
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}
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exports.variance = variance;
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exports.interval = interval;
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exports.parseCron = parseCron;
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exports.cron = cron;
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