moonfire-nvr/ui-src/lib/support/TimeFormatter.js

120 lines
4.2 KiB
JavaScript

// vim: set et sw=2 ts=2:
//
// This file is part of Moonfire NVR, a security camera digital video recorder.
// Copyright (C) 2018 Dolf Starreveld <dolf@starreveld.com>
//
// This program 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.
//
// In addition, as a special exception, the copyright holders give
// permission to link the code of portions of this program with the
// OpenSSL library under certain conditions as described in each
// individual source file, and distribute linked combinations including
// the two.
//
// You must obey the GNU General Public License in all respects for all
// of the code used other than OpenSSL. If you modify file(s) with this
// exception, you may extend this exception to your version of the
// file(s), but you are not obligated to do so. If you do not wish to do
// so, delete this exception statement from your version. If you delete
// this exception statement from all source files in the program, then
// also delete it here.
//
// This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
import moment from 'moment-timezone';
export const defaultTimeFormat = 'YYYY-MM-DD HH:mm:ss';
/**
* Class for formatting timestamps.
*
* There are methods for formatting timestamp in three different unit systems:
* - 90k: The units are multiples of 1/90,000th of a second
* - Sec: The units are multiples of seconds
* - Ms: The units are multiples of milliseconds
*
* The object is initialized with a format string and a timezone. The timezone
* is necessary to format times in that timezone.
*
* The format string is based on those accepted by moment.js with one addition
* detailed in formatTimeStamp90k.
*/
export default class TimeFormatter {
/**
* Construct with specific format string and timezone.
*
* @param {String} formatStr Format specification string
* @param {String} tz Timezone, e.g. "America/Los_Angeles"
*/
constructor(formatStr, tz) {
this._formatStr = formatStr || defaultTimeFormat;
this._tz = tz;
}
/**
* Get current format string
*
* @return {String} Format specification string
*/
get formatStr() {
return this._formatStr;
}
/**
* Get current timezone
*
* @return {String} Timezone
*/
get tz() {
return this._tz;
}
/**
* Produces a human-readable timestamp in 90k units.
*
* The format is anything understood by moment's format function,
* with the addition of one special format indicator consisting of
* five successive Fs. If this pattern is used more than once,
* only the first one will be handled. Subsequent ones will become
* literal strings with five Fs.
*
* Using normal format codes, precision of up the three S (SSS) is
* supported by moment to display decimal seconds. "moment" truncates
* the value passed in to its constructor, effectively truncating
* any fractional values in the timestamp. This function rounds
* to compensate for that, except in the case of the FFFFF pattern,
* where rounding is left out for historical reasons.
*
* FFFFF produces a string indicating how many 90k units are present
* in the sub-second portion of the timestamp. Therefore this is *not*
* a decimal fraction!
*
* @param {Number} ts90k timestamp in 90,000ths of a second resolution
* @return {String} Formatted timestamp
*/
formatTimeStamp90k(ts90k) {
let format = this._formatStr;
const ms = ts90k / 90.0;
const fracFmt = 'FFFFF';
let fracLoc = format.indexOf(fracFmt);
if (fracLoc != -1) {
const frac = ts90k % 90000;
format =
format.substr(0, fracLoc) +
String(100000 + frac).substr(1) +
format.substr(fracLoc + fracFmt.length);
}
return moment.tz(ms, this._tz).format(format);
}
}