rfid

abstract.js

'use strict';

var bigInt = require("big-integer");

var self = {
	epc: undefined,
	base: undefined,

	parse: function(val) {
		for (var p in self.parts)
			if (self.parts.hasOwnProperty(p))
				self.parts[p] = undefined;

		self.epc = val;
	},

	getUri: function(val) {
		if (!val)
			val = self.epc;
	},

	getLength: function(val) {
		if (val)
			return val.length * 4;
		else
			return 0;
	},

	parts: {
		Header: undefined,
		Filter: undefined,
		Partition: undefined,
		CompanyPrefix: undefined,
		ItemReference: undefined,
		SerialNumber: undefined,
		SerialReference: undefined,
		LocationReference: undefined,
		Extension: undefined,
		AssetType: undefined,
		IndividualAssetReference: undefined,
		ServiceReference: undefined,
		DocumentType: undefined,
		ManagerNumber: undefined,
		ObjectClass: undefined,
		CAGEOrDODAAC: undefined
	},

	bitsHelper: function(val, len, valbase) {
		var self = this;

		self.val = val;
		self.bitlength = len;

		if (!valbase)
			valbase = 16;

		self.bits = bigInt(val, valbase).toString(2);
		self.bits = Array(len - self.bits.length + 1).join('0') + self.bits;
	}
};

self.base = self;

module.exports = self;

parser.js

'use strict';

var TAG = 'parser.sgtin';
var header = '00110000';
var partition = {
	bits: {
		company: [40, 37, 34, 30, 27, 24, 20],
		reference: [4, 7, 10, 14, 17, 20, 24]
	},
	digits: {
		company: [12, 11, 10, 9, 8, 7, 6],
		reference: [1, 2, 3, 4, 5, 6, 7]
	}
};

var Abstract = require('./abstract');

var self = Object.create(Abstract, {
	parse: {
		value: function(val) {
				try {
					self.base.parse(val);

					var bh = new self.base.bitsHelper(val, 96);

					if (bh.bits.slice(0, 8) !== header)
						throw new Error(val + ' is not a valid SGTIN.');

					self.parts.Header = bh.bits.slice(0, 8);
					self.parts.Filter = parseInt(bh.bits.slice(8, 11), 2);
					self.parts.Partition = parseInt(bh.bits.slice(11, 14), 2);

					var companyPrefixEnd = 14 + partition.bits.company[self.parts.Partition];

					var company = parseInt(bh.bits.slice(14, companyPrefixEnd), 2).toString();
					company = Array(partition.digits.company[self.parts.Partition] - company.length + 1).join('0') + company;

					self.parts.CompanyPrefix = company;

					var item = parseInt(bh.bits.slice(companyPrefixEnd, companyPrefixEnd + partition.bits.reference[self.parts.Partition]), 2).toString();
					item = Array(partition.digits.reference[self.parts.Partition] - item.length + 1).join('0') + item;

					self.parts.ItemReference = item;
					self.parts.SerialNumber = parseInt(bh.bits.slice(58), 2);

					return self;
				} catch (e) {
					console.error('FUUUUUU', e);
				}
		}
	}
});

module.exports = self;