nixfilter-uartrfid/rdm63.coffee

Filters for decoding the data sent by certain RFID readers connected via UART

`#!/usr/bin/env node

'use strict'`

# Require the "nixfilter" module
nixfilter = require('nixfilter')

# Import/Require the local "utils" module
utils = require('./utils')

# Define the filter and register it on the module
nixfilter.filter module,
	description: 'Parse and output the data sent by certain EM4100-125kHz-RFID-Readers connected via UART 9600 8N1 (e.g. RDM630, RDM6300)'

	input_reader: nixfilter.reader.byte()

	add_arguments: (argument_parser) ->
		argument_parser.addArgument ['--format', '-f'],
			choices: Object.keys(utils.formats)
			defaultValue: '08H>10D'
			help: 'The output format (default: "08H>10D")'
		return

	setup: ->
		@state = 'read_start'

	on_input: (input_byte) ->
		switch @state
			when 'read_start'
				if (input_byte is 0x02)
					@data_string = ''
					@state = 'read_data'
			when 'read_data'
				input_character = String.fromCharCode(input_byte)
				if (input_character in '0123456789ABCDEF')
					@data_string += input_character
					if (@data_string.length is 12)
						@state = 'read_stop'
				else
					@state = 'read_start'
			when 'read_stop'
				if (input_byte is 0x03)
					checksum = 0
					for index in [0...5]
						checksum ^= utils.get_data_byte_at(@data_string, index)
					if (checksum is utils.get_data_byte_at(@data_string, 5))
						data = utils.parse_data(@data_string)
						@output(data[@args.format])
				@state = 'read_start'
		return