diff --git a/cobie.js b/cobie.js new file mode 100644 index 0000000..dc95493 --- /dev/null +++ b/cobie.js @@ -0,0 +1,175 @@ +const COBIE_EPOCH = 0; + +const COBIE_UNITS = { + second: 1, + xenocycle: 0x10, + quantic: 0x100, + chronon: 0x1000, + eonstrip: 0x10000, + megasequence: 0x100000, + cosmocycle: 0x1000000, + galactic_year: 0x10000000, + universal_eon: 0x100000000, + celestial_era: 0x1000000000, + epoch_of_cosmos: 0x10000000000, + cosmic_aeon: 0x100000000000, + metaepoch: 0x1000000000000, + eternum: 0x10000000000000, + infinitum: 0x100000000000000, + astralmillennia: 0x1000000000000000 +}; + +function floorDiv(a, b) { + return Math.trunc(a / b); +} + +function parseCobiets(str) { + const m = /^([+-]?)([0-9A-Fa-f]+)\.([0-9A-Fa-f]{1,})$/.exec(str.trim()); + if (!m) return null; + const sign = m[1] === '-' ? -1 : 1; + + const allDateKeys = [ + 'astralmillennia','infinitum','eternum','metaepoch','cosmic_aeon', + 'epoch_of_cosmos','celestial_era','universal_eon','galactic_year', + 'cosmocycle','megasequence','eonstrip' + ]; + + let rawDateHex = m[2]; + if (rawDateHex.length < allDateKeys.length) { + rawDateHex = rawDateHex.padStart(allDateKeys.length, '0'); + } + + let dateKeys = [...allDateKeys]; + if (rawDateHex.length > allDateKeys.length) { + const extraCount = rawDateHex.length - allDateKeys.length; + for (let i = 0; i < extraCount; i++) { + dateKeys.unshift(null); + } + } + + const timeHexRaw = m[3]; + const timeHex = timeHexRaw.padStart(4, '0'); + const timeKeys = ['chronon', 'quantic', 'xenocycle', 'second']; + + let total = 0; + for (let i = 0; i < rawDateHex.length; i++) { + const digit = parseInt(rawDateHex[i], 16); + const key = dateKeys[i]; + if (key === null) { + const power = rawDateHex.length - 1 - i; + total += digit * Math.pow(16, power) * COBIE_UNITS['eonstrip']; + } else { + total += digit * COBIE_UNITS[key]; + } + } + + timeHex.split('').forEach((h, i) => { + total += parseInt(h, 16) * COBIE_UNITS[timeKeys[i]]; + }); + + return sign * total; +} + +function getTAIOffsetAt(date) { + const taiEpoch = new Date('1958-01-01T00:00:00Z'); + if (date < taiEpoch) { return 0; } + const leapSeconds = [ + { date: '1972-01-01T00:00:00Z', offset: 10 }, + { date: '1972-07-01T00:00:00Z', offset: 11 }, + { date: '1973-01-01T00:00:00Z', offset: 12 }, + { date: '1974-01-01T00:00:00Z', offset: 13 }, + { date: '1975-01-01T00:00:00Z', offset: 14 }, + { date: '1976-01-01T00:00:00Z', offset: 15 }, + { date: '1977-01-01T00:00:00Z', offset: 16 }, + { date: '1978-01-01T00:00:00Z', offset: 17 }, + { date: '1979-01-01T00:00:00Z', offset: 18 }, + { date: '1980-01-01T00:00:00Z', offset: 19 }, + { date: '1981-07-01T00:00:00Z', offset: 20 }, + { date: '1982-07-01T00:00:00Z', offset: 21 }, + { date: '1983-07-01T00:00:00Z', offset: 22 }, + { date: '1985-07-01T00:00:00Z', offset: 23 }, + { date: '1988-01-01T00:00:00Z', offset: 24 }, + { date: '1990-01-01T00:00:00Z', offset: 25 }, + { date: '1991-01-01T00:00:00Z', offset: 26 }, + { date: '1992-07-01T00:00:00Z', offset: 27 }, + { date: '1993-07-01T00:00:00Z', offset: 28 }, + { date: '1994-07-01T00:00:00Z', offset: 29 }, + { date: '1996-01-01T00:00:00Z', offset: 30 }, + { date: '1997-07-01T00:00:00Z', offset: 31 }, + { date: '1999-01-01T00:00:00Z', offset: 32 }, + { date: '2006-01-01T00:00:00Z', offset: 33 }, + { date: '2009-01-01T00:00:00Z', offset: 34 }, + { date: '2012-07-01T00:00:00Z', offset: 35 }, + { date: '2015-07-01T00:00:00Z', offset: 36 }, + { date: '2017-01-01T00:00:00Z', offset: 37 } + ]; + + for (let i = 0; i < leapSeconds.length; i++) { + const leapDate = new Date(leapSeconds[i].date); + if (date < leapDate) { + return i === 0 ? 10 : leapSeconds[i - 1].offset; + } + } + return 37; +} + +function toCobiets(date) { + const utcSec = floorDiv(date.getTime(), 1000); + const taiSec = utcSec + getTAIOffsetAt(date); + return taiSec - COBIE_EPOCH; +} + +function fromCobiets(cobiets) { + const taiSeconds = cobiets + COBIE_EPOCH; + const taiMs = taiSeconds * 1000; + let utcMs = taiMs; + for (let i = 0; i < 3; i++) { + const off = getTAIOffsetAt(new Date(utcMs)); + utcMs = taiMs - off * 1000; + } + return new Date(utcMs); +} + +const UNIT_KEYS = [ + 'astralmillennia','infinitum','eternum','metaepoch','cosmic_aeon','epoch_of_cosmos','celestial_era','universal_eon','galactic_year','cosmocycle','megasequence','eonstrip','chronon','quantic','xenocycle','second' +]; + +function breakdownNonNeg(cob) { + let rem = cob, bd = {}; + for (let key of UNIT_KEYS) { + bd[key] = floorDiv(rem, COBIE_UNITS[key]); + rem %= COBIE_UNITS[key]; + } + return bd; +} + +function formatCobieTimestamp(cobiets) { + const sign = cobiets < 0 ? '-' : '+'; + const absCob = Math.abs(cobiets); + const bd = breakdownNonNeg(absCob); + + const dateUnits = [ + 'astralmillennia','infinitum','eternum','metaepoch','cosmic_aeon','epoch_of_cosmos','celestial_era','universal_eon','galactic_year','cosmocycle','megasequence','eonstrip' + ]; + + let rawDateHex = dateUnits.map(key => bd[key].toString(16)).join(''); + rawDateHex = rawDateHex.replace(/^0+/, ''); + if (rawDateHex === '') rawDateHex = '0'; + + const timeHex = [bd.chronon, bd.quantic, bd.xenocycle, bd.second] + .map(n => n.toString(16)).join(''); + + const paddedTimeHex = timeHex.padStart(4, '0'); + return sign + rawDateHex + '.' + paddedTimeHex; +} + +module.exports = { + COBIE_EPOCH, + COBIE_UNITS, + floorDiv, + parseCobiets, + getTAIOffsetAt, + toCobiets, + fromCobiets, + formatCobieTimestamp +}; diff --git a/package.json b/package.json new file mode 100644 index 0000000..ae13978 --- /dev/null +++ b/package.json @@ -0,0 +1,10 @@ +{ + "name": "cobie", + "version": "1.0.0", + "description": "CoBiE Time utilities", + "main": "cobie.js", + "scripts": { + "test": "node --test" + }, + "license": "MIT" +} diff --git a/test/cobie.test.js b/test/cobie.test.js new file mode 100644 index 0000000..07533b3 --- /dev/null +++ b/test/cobie.test.js @@ -0,0 +1,35 @@ +const assert = require('node:assert'); +const { parseCobiets, formatCobieTimestamp, toCobiets, fromCobiets, getTAIOffsetAt } = require('..'); + +const test = require('node:test'); + +test('parseCobiets basic values', () => { + assert.strictEqual(parseCobiets('0.0000'), 0); + assert.strictEqual(parseCobiets('1.0000'), 0x10000); + assert.strictEqual(parseCobiets('-1.0000'), -0x10000); + assert.strictEqual(parseCobiets('0.0001'), 1); +}); + +test('formatCobieTimestamp round trip', () => { + const str = '+1.0001'; + const parsed = parseCobiets(str); + assert.strictEqual(formatCobieTimestamp(parsed), str); +}); + +test('getTAIOffsetAt known dates', () => { + assert.strictEqual(getTAIOffsetAt(new Date('1972-01-01T00:00:00Z')), 10); + assert.strictEqual(getTAIOffsetAt(new Date('1973-01-01T00:00:00Z')), 12); + assert.strictEqual(getTAIOffsetAt(new Date('2017-01-01T00:00:00Z')), 37); +}); + +test('toCobiets/fromCobiets round trip', () => { + const dates = [ + new Date('1970-01-01T00:00:00Z'), + new Date('2017-01-01T00:00:00Z') + ]; + for (const d of dates) { + const cob = toCobiets(d); + const back = fromCobiets(cob); + assert.strictEqual(back.toISOString(), d.toISOString()); + } +});