node-red-contrib-uhppoted
Version:
A set of nodes for the UHPPOTE Wiegand Access Controller
950 lines (797 loc) • 25.4 kB
JavaScript
const { Buffer } = require('node:buffer')
const ipx = require('./ipx.js')
module.exports = {
/**
* Encodes a get-device request.
*
* @param {number} deviceId Controller serial number (0 implies a get-all-devices)
*
* @return {buffer} 64 byte NodeJS buffer with encoded get-device request
*/
GetDevice: function (deviceId) {
const request = Buffer.alloc(64)
request.writeUInt8(0x17, 0)
request.writeUInt8(0x94, 1)
if (deviceId !== null) {
request.writeUInt32LE(deviceId, 4)
}
return request
},
/**
* Encodes a set-address request.
*
* @param {number} deviceId Controller serial number
* @param {string} address IPv4 address assigned to controller
* @param {string} netmask IPv4 subnet mask assigned to controller
* @param {string} gateway IPv4 gateway address
*
* @return {buffer} 64 byte NodeJS buffer with encoded set-address request
*/
SetIP: function (deviceId, { address, netmask, gateway } = {}) {
const request = Buffer.alloc(64)
request.writeUInt8(0x17, 0)
request.writeUInt8(0x96, 1)
request.writeUInt32LE(deviceId, 4)
ipx.toBuffer(address, request, 8)
ipx.toBuffer(netmask, request, 12)
ipx.toBuffer(gateway, request, 16)
request.writeUInt32LE(0x55aaaa55, 20)
return request
},
/**
* Encodes a set-time request.
*
* @param {number} deviceId Controller serial number
* @param {date} datetime Date and time to which to set controller time
*
* @return {buffer} 64 byte NodeJS buffer with encoded set-time request
*/
SetTime: function (deviceId, { datetime } = {}) {
const request = Buffer.alloc(64)
request.writeUInt8(0x17, 0)
request.writeUInt8(0x30, 1)
request.writeUInt32LE(deviceId, 4)
datetime2bin(datetime).copy(request, 8)
return request
},
/**
* Encodes a get-time request.
*
* @param {number} deviceId Controller serial number
*
* @return {buffer} 64 byte NodeJS buffer with encoded get-time request.
*/
GetTime: function (deviceId) {
const request = Buffer.alloc(64)
request.writeUInt8(0x17, 0)
request.writeUInt8(0x32, 1)
request.writeUInt32LE(deviceId, 4)
return request
},
/**
* Encodes a set-door-control request.
*
* @param {number} deviceId Controller serial number
* @param {number} door Door number in the range [1..4]
* @param {number} delay Door open delay (in seconds)
* @param {string} control Door control state ('normally open', 'normally closed' or 'controlled')
*
* @return {buffer} 64 byte NodeJS buffer with encoded set-door-control request
*/
SetDoorControl: function (deviceId, { door, delay, control } = {}) {
const opcodes = require('../nodes/opcodes.js')
const request = Buffer.alloc(64)
request.writeUInt8(0x17, 0)
request.writeUInt8(0x80, 1)
request.writeUInt32LE(deviceId, 4)
request.writeUInt8(door, 8)
request.writeUInt8(delay, 10)
switch (control) {
case opcodes.NormallyOpen:
request.writeUInt8(1, 9)
break
case opcodes.NormallyClosed:
request.writeUInt8(2, 9)
break
case opcodes.Controlled:
request.writeUInt8(3, 9)
break
default:
throw new Error(`invalid door control ${control}`)
}
return request
},
/**
* Encodes a get-door-control request.
*
* @param {number} deviceId Controller serial number
* @param {number} door Door number in the range [1..4]
*
* @return {buffer} 64 byte NodeJS buffer with encoded get-door-control request.
*/
GetDoorControl: function (deviceId, { door } = {}) {
const request = Buffer.alloc(64)
request.writeUInt8(0x17, 0)
request.writeUInt8(0x82, 1)
request.writeUInt32LE(deviceId, 4)
request.writeUInt8(door, 8)
return request
},
/**
* Encodes a get-listener request.
*
* @param {number} deviceId Controller serial number
*
* @return {buffer} 64 byte NodeJS buffer with encoded get-listener request
*/
GetListener: function (deviceId) {
const request = Buffer.alloc(64)
request.writeUInt8(0x17, 0)
request.writeUInt8(0x92, 1)
request.writeUInt32LE(deviceId, 4)
return request
},
/**
* Encodes a set-listener request.
*
* @param {number} deviceId Controller serial number
* @param {string} address IPv4 listener address for controller events
* @param {uint16} port IPv4 listener port for controller events
* @param {uint8} interval Auto-send interval (seconds) - 0 for no auto-send.
*
* @return {buffer} 64 byte NodeJS buffer with encoded set-address request
*/
SetListener: function (deviceId, { address, port, interval } = {}) {
const request = Buffer.alloc(64)
request.writeUInt8(0x17, 0)
request.writeUInt8(0x90, 1)
request.writeUInt32LE(deviceId, 4)
ipx.toBuffer(address, request, 8)
request.writeUInt16LE(port, 12)
request.writeUInt8(interval, 14)
return request
},
/**
* Encode a record-special-events request.
*
* @param {number} deviceId Controller serial number
* @param {number} enable true/false
*
* @return {buffer} 64 byte NodeJS buffer with encoded record-special-events request.
*/
RecordSpecialEvents: function (deviceId, { enable } = {}) {
const request = Buffer.alloc(64)
request.writeUInt8(0x17, 0)
request.writeUInt8(0x8e, 1)
request.writeUInt32LE(deviceId, 4)
if (enable) {
request.writeUInt8(1, 8)
} else {
request.writeUInt8(0, 8)
}
return request
},
/**
* Encodes a get-status request.
*
* @param {number} deviceId Controller serial number
*
* @return {buffer} 64 byte NodeJS buffer with encoded get-status request.
*/
GetStatus: function (deviceId) {
const request = Buffer.alloc(64)
request.writeUInt8(0x17, 0)
request.writeUInt8(0x20, 1)
request.writeUInt32LE(deviceId, 4)
return request
},
/**
* Encodes an open-door request.
*
* @param {number} deviceId Controller serial number
* @param {number} door Door number in the range [1..4]
*
* @return {buffer} 64 byte NodeJS buffer with encoded open-door request.
*/
OpenDoor: function (deviceId, { door } = {}) {
const request = Buffer.alloc(64)
request.writeUInt8(0x17, 0)
request.writeUInt8(0x40, 1)
request.writeUInt32LE(deviceId, 4)
request.writeUInt8(door, 8)
return request
},
/**
* Encodes a get-cards request.
*
* @param {number} deviceId Controller serial number
*
* @return {buffer} 64 byte NodeJS buffer with encoded get-cards request.
*/
GetCards: function (deviceId, _object) {
const request = Buffer.alloc(64)
request.writeUInt8(0x17, 0)
request.writeUInt8(0x58, 1)
request.writeUInt32LE(deviceId, 4)
return request
},
/**
* Encode a get-card-by-id request.
*
* @param {number} deviceId Controller serial number
* @param {number} card Card number
*
* @return {buffer} 64 byte NodeJS buffer with encoded get-card-by-id request.
*/
GetCardByID: function (deviceId, { card } = {}) {
const request = Buffer.alloc(64)
request.writeUInt8(0x17, 0)
request.writeUInt8(0x5a, 1)
request.writeUInt32LE(deviceId, 4)
request.writeUInt32LE(card, 8)
return request
},
/**
* Encode a get-card-by-index request.
*
* @param {number} deviceId Controller serial number
* @param {number} index Card index
*
* @return {buffer} 64 byte NodeJS buffer with encoded get-card-by-index request.
*/
GetCardByIndex: function (deviceId, { index } = {}) {
const request = Buffer.alloc(64)
request.writeUInt8(0x17, 0)
request.writeUInt8(0x5c, 1)
request.writeUInt32LE(deviceId, 4)
request.writeUInt32LE(index, 8)
return request
},
/**
* Encode a put-card request.
*
* @param {number} deviceId Controller serial number
* @param {number} card Card number
* @param {date} from Card validity start date
* @param {date} to Card validity end date
* @param {object} doors Object mapping door numbers 1..4 to access permission. A permission
* may be true, false or a time profile in the range [2..254]
* @param {number} PIN Optional card PIN code in the range [0..999999]
*
* @return {buffer} 64 byte NodeJS buffer with encoded put-card request.
*/
PutCard: function (deviceId, { card, from, to, doors, PIN } = {}) {
const request = Buffer.alloc(64)
request.writeUInt8(0x17, 0)
request.writeUInt8(0x50, 1)
request.writeUInt32LE(deviceId, 4)
request.writeUInt32LE(card, 8)
date2bin(from).copy(request, 12)
date2bin(to).copy(request, 16)
;['1', '2', '3', '4'].forEach((door, index) => {
if (Object.prototype.hasOwnProperty.call(doors, door)) {
const permission = doors[door]
const offset = 20 + index
if (typeof permission === 'boolean') {
request.writeUInt8(permission ? 0x01 : 0x00, offset)
} else {
const profileID = Number(permission)
if (!Number.isNaN(profileID) && Number.isInteger(profileID) && profileID >= 2 && profileID <= 254) {
request.writeUInt8(profileID, offset)
}
}
}
})
if (PIN) {
const pin = Number.parseInt(`${PIN}`)
if (Number.isNaN(pin) || pin < 0 || pin > 999999) {
throw new Error(`invalid card PIN value ${PIN}`)
} else {
uint24(pin).copy(request, 24)
}
}
return request
},
/**
* Encode a delete-card request.
*
* @param {number} deviceId Controller serial number
* @param {number} card Card number to delete
*
* @return {buffer} 64 byte NodeJS buffer with encoded delete-card request.
*/
DeleteCard: function (deviceId, { card } = {}) {
const request = Buffer.alloc(64)
request.writeUInt8(0x17, 0)
request.writeUInt8(0x52, 1)
request.writeUInt32LE(deviceId, 4)
request.writeUInt32LE(card, 8)
return request
},
/**
* Encode a delete-all-cards request.
*
* @param {number} deviceId Controller serial number
*
* @return {buffer} 64 byte NodeJS buffer with encoded delete-all-cards request.
*/
DeleteCards: function (deviceId) {
const request = Buffer.alloc(64)
request.writeUInt8(0x17, 0)
request.writeUInt8(0x54, 1)
request.writeUInt32LE(deviceId, 4)
request.writeUInt32LE(0x55aaaa55, 8)
return request
},
/**
* Encodes a get-time-profile request.
*
* @param {number} deviceId Controller serial number
* @param {number} profileId Time profile ID [2..254]
*
* @return {buffer} 64 byte NodeJS buffer with encoded get-time-profile request.
*/
GetTimeProfile: function (deviceId, { profileId } = {}) {
const request = Buffer.alloc(64)
request.writeUInt8(0x17, 0)
request.writeUInt8(0x98, 1)
request.writeUInt32LE(deviceId, 4)
request.writeUInt8(profileId, 8)
return request
},
/**
* Encodes a set-time-profile request.
*
* @param {number} deviceId Controller serial number
* @param {object} profile Time profile
*
* @return {buffer} 64 byte NodeJS buffer with encoded set-time-profile request.
*/
SetTimeProfile: function (deviceId, { profile } = {}) {
const map = new Map([
['mo', 17],
['tu', 18],
['we', 19],
['th', 20],
['fr', 21],
['sa', 22],
['su', 23],
])
let profileID = 0
let linked = 0
if (profile.id) {
profileID = Number(profile.id)
}
if (Number.isNaN(profileID) || !Number.isInteger(profileID) || profileID < 2 || profileID > 254) {
throw new Error(`invalid profile ID (${profile.id})`)
}
if (profile.linkedTo) {
linked = Number(profile.linkedTo)
if (Number.isNaN(linked) || !Number.isInteger(linked) || linked < 2 || linked > 254) {
throw new Error(`invalid linked profile (${profile.linkedTo})`)
}
}
const request = Buffer.alloc(64)
request.writeUInt8(0x17, 0)
request.writeUInt8(0x88, 1)
request.writeUInt32LE(deviceId, 4)
request.writeUInt8(profile.id, 8)
date2bin(profile.valid.from).copy(request, 9)
date2bin(profile.valid.to).copy(request, 13)
if (profile.weekdays) {
profile.weekdays.forEach((day) => {
map.forEach((v, k) => {
if (day.toLowerCase().startsWith(k)) {
request.writeUInt8(1, v)
}
})
})
}
if (profile.segments) {
const re = /[0-9]{2}:[0-9]{2}/
let offset = 24
profile.segments.slice(0, 3).forEach((segment) => {
if (segment.start && segment.end && re.test(segment.start) && re.test(segment.end)) {
HHmm2bin(segment.start).copy(request, offset)
HHmm2bin(segment.end).copy(request, offset + 2)
offset = offset + 4
}
})
}
request.writeUInt8(linked, 36)
return request
},
/**
* Encodes a clear-time-profiles request.
*
* @param {number} deviceId Controller serial number
*
* @return {buffer} 64 byte NodeJS buffer with encoded clear-time-profiles request.
*/
ClearTimeProfiles: function (deviceId) {
const request = Buffer.alloc(64)
request.writeUInt8(0x17, 0)
request.writeUInt8(0x8a, 1)
request.writeUInt32LE(deviceId, 4)
request.writeUInt32LE(0x55aaaa55, 8)
return request
},
/**
* Encodes an add-task request.
*
* @param {number} deviceId Controller serial number
* @param {object} task Task definition
*
* @return {buffer} 64 byte NodeJS buffer with encoded add-task request.
*/
AddTask: function (deviceId, { task } = {}) {
const days = new Map([
['mo', 16],
['tu', 17],
['we', 18],
['th', 19],
['fr', 20],
['sa', 21],
['su', 22],
])
const tasks = new Map([
['doorcontrolled', 0],
['doornormallyopen', 1],
['doornormallyclosed', 2],
['disabletimeprofile', 3],
['enabletimeprofile', 4],
['cardnopassword', 5],
['cardinpassword', 6],
['cardpassword', 7],
['enablemorecards', 8],
['disablemorecards', 9],
['triggeronce', 10],
['disablepushbutton', 11],
['enablepushbutton', 12],
])
const request = Buffer.alloc(64)
request.writeUInt8(0x17, 0)
request.writeUInt8(0xa8, 1)
request.writeUInt32LE(deviceId, 4)
date2bin(task.valid.from).copy(request, 8)
date2bin(task.valid.to).copy(request, 12)
if (task.weekdays) {
task.weekdays.forEach((day) => {
days.forEach((v, k) => {
if (day.toLowerCase().startsWith(k)) {
request.writeUInt8(1, v)
}
})
})
}
if (task.start && /[0-9]{2}:[0-9]{2}/.test(task.start)) {
HHmm2bin(task.start).copy(request, 23)
} else {
throw new Error(`invalid task start time (${task.start})`)
}
request.writeUInt8(task.door, 25)
if (isNaN(task.task)) {
const key = task.task.replace(/[^a-z]+/gi, '')
if (tasks.has(key)) {
request.writeUInt8(tasks.get(key), 26)
} else {
throw new Error(`invalid task '${task.task}'`)
}
} else if (!Number.isInteger(task.task) || task.task < 1 || task > 13) {
throw new Error(`invalid task ID '${task.task}' - valid range is [1..13]`)
} else {
request.writeUInt8(task.task - 1, 26)
}
if (task.cards) {
if (!isNaN(task.cards) && Number.isInteger(task.cards)) {
request.writeUInt8(task.cards, 27)
} else {
throw new Error(`invalid value for 'cards' (${task.cards})`)
}
}
return request
},
/**
* Encodes a clear-task-list request.
*
* @param {number} deviceId Controller serial number
*
* @return {buffer} 64 byte NodeJS buffer with encoded clear-task-list request.
*/
ClearTaskList: function (deviceId) {
const request = Buffer.alloc(64)
request.writeUInt8(0x17, 0)
request.writeUInt8(0xa6, 1)
request.writeUInt32LE(deviceId, 4)
request.writeUInt32LE(0x55aaaa55, 8)
return request
},
/**
* Encodes a refresh-task-list request.
*
* @param {number} deviceId Controller serial number
*
* @return {buffer} 64 byte NodeJS buffer with encoded refresh-task-list request.
*/
RefreshTaskList: function (deviceId) {
const request = Buffer.alloc(64)
request.writeUInt8(0x17, 0)
request.writeUInt8(0xac, 1)
request.writeUInt32LE(deviceId, 4)
request.writeUInt32LE(0x55aaaa55, 8)
return request
},
/**
* Encode a get-event-index request.
*
* @param {number} deviceId Controller serial number
*
* @return {buffer} 64 byte NodeJS buffer with encoded get-event-index request.
*/
GetEventIndex: function (deviceId) {
const request = Buffer.alloc(64)
request.writeUInt8(0x17, 0)
request.writeUInt8(0xb4, 1)
request.writeUInt32LE(deviceId, 4)
return request
},
/**
* Encode a set-event-index request.
*
* @param {number} deviceId Controller serial number
* @param {number} index Index to which to set controller internal event index
*
* @return {buffer} 64 byte NodeJS buffer with encoded set-event-index request.
*/
SetEventIndex: function (deviceId, { index } = {}) {
const request = Buffer.alloc(64)
request.writeUInt8(0x17, 0)
request.writeUInt8(0xb2, 1)
request.writeUInt32LE(deviceId, 4)
request.writeUInt32LE(index, 8)
request.writeUInt32LE(0x55aaaa55, 12)
return request
},
/**
* Encode a get-event request.
*
* @param {number} deviceId Controller serial number
* @param {number} index Index of event to retrieve
*
* @return {buffer} 64 byte NodeJS buffer with encoded get-event request.
*/
GetEvent: function (deviceId, { index } = {}) {
const request = Buffer.alloc(64)
request.writeUInt8(0x17, 0)
request.writeUInt8(0xb0, 1)
request.writeUInt32LE(deviceId, 4)
request.writeUInt32LE(index, 8)
return request
},
/**
* Encode a set-pc-control request.
*
* @param {number} deviceId Controller serial number
* @param {number} enable true/false
*
* @return {buffer} 64 byte NodeJS buffer with encoded set-pc-control request.
*/
SetPCControl: function (deviceId, { enable } = {}) {
const request = Buffer.alloc(64)
request.writeUInt8(0x17, 0)
request.writeUInt8(0xa0, 1)
request.writeUInt32LE(deviceId, 4)
request.writeUInt32LE(0x55aaaa55, 8)
if (enable) {
request.writeUInt8(1, 12)
} else {
request.writeUInt8(0, 12)
}
return request
},
/**
* Encodes a set-interlock request.
*
* @param {number} deviceId Controller serial number
* @param {number} interlock 0,1,2,3,4 or 8, corresponding to modes
* - 1&2
* - 3&4
* - 1&2,3&4
* - 1&2&3
* - 1&2&3&4
*
* @return {buffer} 64 byte NodeJS buffer with encoded set-interlock request.
*/
SetInterlock: function (deviceId, { interlock } = {}) {
const request = Buffer.alloc(64)
request.writeUInt8(0x17, 0)
request.writeUInt8(0xa2, 1)
request.writeUInt32LE(deviceId, 4)
request.writeUInt8(interlock, 8)
return request
},
/**
* Encodes an activate-keypads request.
*
* @param {number} deviceId Controller serial number
* @param {object} keypads Object with activated/deactivated keypads:
* {
* 1: true/false,
* 2: true/false,
* 3: true/false,
* 4: true/false
* }
*
* @return {buffer} 64 byte NodeJS buffer with encoded activate-keypads request.
*/
ActivateKeypads: function (deviceId, { keypads } = {}) {
const request = Buffer.alloc(64)
request.writeUInt8(0x17, 0)
request.writeUInt8(0xa4, 1)
request.writeUInt32LE(deviceId, 4)
request.writeUInt8(keypads[1] ? 0x01 : 0x00, 8)
request.writeUInt8(keypads[2] ? 0x01 : 0x00, 9)
request.writeUInt8(keypads[3] ? 0x01 : 0x00, 10)
request.writeUInt8(keypads[4] ? 0x01 : 0x00, 11)
return request
},
/**
* Encodes a set-door-passcodes request.
*
* @param {number} deviceId Controller serial number
* @param {number} door Controller door ID (in the range [1..4])
* @param {array} passcodes Array of passcodes (in the range [0..999999])
*
* @return {buffer} 64 byte NodeJS buffer with encoded activate-keypads request.
*/
SetDoorPasscodes: function (deviceId, { door, passcodes } = {}) {
const request = Buffer.alloc(64)
request.writeUInt8(0x17, 0)
request.writeUInt8(0x8c, 1)
request.writeUInt32LE(deviceId, 4)
request.writeUInt8(door, 8)
for (let i = 0; i < 4; i++) {
if (passcodes && passcodes.length > i) {
const passcode = passcodes[i] > 0 && passcodes[i] < 1000000 ? passcodes[i] : 0
request.writeUInt32LE(passcode, 12 + 4 * i)
}
}
return request
},
/**
* Encodes a get-antipassback request.
*
* @param {number} deviceId Controller serial number
*
* @return {buffer} 64 byte NodeJS buffer with encoded get-antipassback request.
*/
GetAntiPassback: function (deviceId) {
const request = Buffer.alloc(64)
request.writeUInt8(0x17, 0)
request.writeUInt8(0x86, 1)
request.writeUInt32LE(deviceId, 4)
return request
},
/**
* Encodes a set-antipassback request.
*
* @param {number} deviceId Controller serial number
* @param {string} antipassback Anti-passback mode ('disabled', '(1:2);(3:4)', '(1,3):(2,4)', '1:(2,3)' or '1:(2,3,4)')
*
* @return {buffer} 64 byte NodeJS buffer with encoded set-antipassback request
*/
SetAntiPassback: function (deviceId, { antipassback } = {}) {
const opcodes = require('../nodes/opcodes.js')
const request = Buffer.alloc(64)
request.writeUInt8(0x17, 0)
request.writeUInt8(0x84, 1)
request.writeUInt32LE(deviceId, 4)
switch (antipassback) {
case opcodes.AntiPassbackDisabled:
request.writeUInt8(0, 8)
break
case opcodes.AntiPassback12_34:
request.writeUInt8(1, 8)
break
case opcodes.AntiPassback13_24:
request.writeUInt8(2, 8)
break
case opcodes.AntiPassback1_23:
request.writeUInt8(3, 8)
break
case opcodes.AntiPassback1_234:
request.writeUInt8(4, 8)
break
default:
throw new Error(`invalid anti-passback ${antipassback}`)
}
return request
},
/**
* Encode a restore-default-parameters request.
*
* @param {number} deviceId Controller serial number
*
* @return {buffer} 64 byte NodeJS buffer with encoded restore-default-parameters request.
*/
RestoreDefaultParameters: function (deviceId) {
const request = Buffer.alloc(64)
request.writeUInt8(0x17, 0)
request.writeUInt8(0xc8, 1)
request.writeUInt32LE(deviceId, 4)
request.writeUInt32LE(0x55aaaa55, 8)
return request
},
}
/**
* Internal utility function to encode a PIN code 24-bit binary.
*
* @param {number} PIN Numeric PIN code in the rangee 0 to 999999
* @param {number} offset Index of time in buffer
*
* @param {buffer} 3 byte NodeJS buffer with little-endian encoded PIN
* @private
*/
function uint24(PIN) {
const bytes = []
bytes.push((PIN >> 0) & 0x00ff)
bytes.push((PIN >> 8) & 0x00ff)
bytes.push((PIN >> 16) & 0x00ff)
return Buffer.from(bytes)
}
/**
* Internal utility function to encode a timestamp as BCD.
*
* @param {string} datetime Timestamp, formatted as yyyy-mm-dd HH:mm:ss
* @param {number} offset Index of time in buffer
*
* @param {buffer} 6 byte NodeJS buffer with BCD encoded timestamp.
*/
function datetime2bin(datetime) {
const bytes = []
const re = /([0-9]{2})([0-9]{2})-([0-9]{2})-([0-9]{2}) ([0-9]{2}):([0-9]{2}):([0-9]{2})/
const match = datetime.match(re)
for (const m of match.slice(1)) {
const b = parseInt(m, 10)
const byte = ((b / 10) << 4) | b % 10
bytes.push(byte)
}
return Buffer.from(bytes)
}
/**
* Internal utility function to encode a date as BCD.
*
* @param {string} date Date, formatted as yyyy-mm-dd
*
* @param {buffer} 4 byte NodeJS buffer with BCD encoded timestamp
*
*/
function date2bin(date) {
const bytes = []
const re = /([0-9]{2})([0-9]{2})-([0-9]{2})-([0-9]{2})/
const match = date.match(re)
for (const m of match.slice(1)) {
const b = parseInt(m, 10)
const byte = ((b / 10) << 4) | b % 10
bytes.push(byte)
}
return Buffer.from(bytes)
}
/**
* Internal utility function to convert an HHmm value to BCD
*
* @param {string} hhmm HHmm, formatted as HH:mm
*
* @param {buffer} 4 byte NodeJS buffer with BCD encoded timestamp
*/
function HHmm2bin(hhmm) {
const bytes = []
const re = /([0-9]{2}):([0-9]{2})/
const match = hhmm.match(re)
for (const m of match.slice(1)) {
const b = parseInt(m, 10)
const byte = ((b / 10) << 4) | b % 10
bytes.push(byte)
}
return Buffer.from(bytes)
}