rfc4122.js

/* Copyright 2014 Tristian Flanagan
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
*/

'use strict';

/* Dependencies */
const crypto = require('crypto');

/* Main Class
 *
 * Based On: https://www.ietf.org/rfc/rfc4122.txt
*/
class RFC4122 {

	constructor (prng) {
		this.prng = prng || Math;

		this.nodeId = crypto.randomBytes(16);
		this.nodeId[0] = this.nodeId[0] | 0x01;

		this.clockSeq = crypto.randomBytes(2);
		this.clockSeq = (this.clockSeq[0] | (this.clockSeq[1] << 8)) & 0x3fff;

		this.lastMTime = 0;
		this.lastNTime = 0;

		return this;
	}

	v1 () {
		let mTime = Date.now(),
			nTime = this.lastNTime + 1;
		
		const delta = (mTime - this.lastMTime) + (nTime - this.lastNTime) / 10000;

		if(delta < 0){
			this.clockSeq = (this.clockSeq + 1) & 0x3fff;

			nTime = 0;
		}else
		if(mTime > this.lastMTime){
			nTime = 0;
		}else
		if(nTime >= 10000){
			return false;
		}

		this.lastMTime = mTime;
		this.lastNTime = nTime;

		mTime += 12219292800000;

		let buffer = new Buffer(10),
			timeLow = ((mTime & 0xfffffff) * 10000 + nTime) % 0x100000000,
			timeHigh = (mTime / 0x100000000 * 10000) & 0xfffffff;

		buffer[0] = timeLow >>> 24 & 0xff;
		buffer[1] = timeLow >>> 16 & 0xff;
		buffer[2] = timeLow >>> 8 & 0xff;
		buffer[3] = timeLow & 0xff;

		buffer[4] = timeHigh >>> 8 & 0xff;
		buffer[5] = timeHigh & 0xff;

		buffer[6] = (timeHigh >>> 24 & 0x0f) | 0x10;
		buffer[7] = (timeHigh >>> 16 & 0x3f) | 0x80;

		buffer[8] = this.clockSeq >>> 8;
		buffer[9] = this.clockSeq & 0xff;

		return byteToHex[buffer[0]] +      byteToHex[buffer[1]] +      byteToHex[buffer[2]] +      byteToHex[buffer[3]] +      '-' +
			   byteToHex[buffer[4]] +      byteToHex[buffer[5]] +      '-' +
			   byteToHex[buffer[6]] +      byteToHex[buffer[7]] +      '-' +
			   byteToHex[buffer[8]] +      byteToHex[buffer[9]] +      '-' +
			   byteToHex[this.nodeId[0]] + byteToHex[this.nodeId[1]] + byteToHex[this.nodeId[2]] + byteToHex[this.nodeId[3]] + byteToHex[this.nodeId[4]] + byteToHex[this.nodeId[5]];
	}

	v3 (namespace, name) {
		return named('md5', 0x30, namespace, name);
	}

	v4 () {
		return bufferToHex(crypto.randomBytes(16), 0x40);
	}

	v4f () {
		let d0 = this.prng.random() * 0xffffffff|0,
			d1 = this.prng.random() * 0xffffffff|0,
			d2 = this.prng.random() * 0xffffffff|0,
			d3 = this.prng.random() * 0xffffffff|0;

		return byteToHex[d0 & 0xff] +              byteToHex[d0 >> 8 & 0xff] +  byteToHex[d0 >> 16 & 0xff] + byteToHex[d0 >> 24 & 0xff] + '-' +
			   byteToHex[d1 & 0xff] +              byteToHex[d1 >> 8 & 0xff] +  '-' +
			   byteToHex[d1 >> 16 & 0x0f | 0x40] + byteToHex[d1 >> 24 & 0xff] + '-' +
			   byteToHex[d2 & 0x3f | 0x80] +       byteToHex[d2 >> 8 & 0xff] +  '-' +
			   byteToHex[d2 >> 16 & 0xff] +        byteToHex[d2 >> 24 & 0xff] + byteToHex[d3 & 0xff] +     byteToHex[d3 >> 8 & 0xff] +  byteToHex[d3 >> 16 & 0xff] + byteToHex[d3 >> 24 & 0xff];
	}

	v5 (namespace, name) {
		return named('sha1', 0x50, namespace, name);
	}

}

/* Auxilary Code */
let byteToHex = [],
	hexToByte = {},
	i = 0, l = 256,
	hex;

for(; i < l; ++i){
	hex = (i + 0x100).toString(16).substr(1);

	hexToByte[hex] = i;
	byteToHex[i] = hex;
}

/* Helpers */
let hexdec = function(s){
	s = (s + '').replace(/[^a-f0-9]/gi, '');

	return parseInt(s, 16);
};

let named = function(hash, version, namespace, name){
	let nHex = namespace.replace(/[\-]/g, ''),
		nStr = '',
		i = 0, l = nHex.length;

	for(; i < l; i += 2){
		nStr += String.fromCharCode(hexdec(nHex[i] + nHex[i + 1]));
	}

	return bufferToHex(crypto.createHash(hash).update(nStr + name).digest(), version);
};

let bufferToHex = function(buffer, version){
	return byteToHex[buffer[0]] +                    byteToHex[buffer[1]] +  byteToHex[buffer[2]] +  byteToHex[buffer[3]] +  '-' +
		   byteToHex[buffer[4]] +                    byteToHex[buffer[5]] +  '-' +
		   byteToHex[(buffer[6] & 0x0f) | version] + byteToHex[buffer[7]] +  '-' +
		   byteToHex[(buffer[8] & 0x3f) | 0x80] +    byteToHex[buffer[9]] +  '-' +
		   byteToHex[buffer[10]] +                   byteToHex[buffer[11]] + byteToHex[buffer[12]] + byteToHex[buffer[13]] + byteToHex[buffer[14]] + byteToHex[buffer[15]];
};

/* Expose Helpers */
RFC4122.hexdec       = hexdec;
RFC4122.named        = named;
RFC4122.bufferToHex  = bufferToHex;

/* Export Module */
if(typeof(module) !== 'undefined' && module.exports){
	module.exports = RFC4122;
}else
if(typeof(define) === 'function' && define.amd){
	define('RFC4122', [], function(){
		return RFC4122;
	});
}

if(typeof(global) !== 'undefined' && typeof(window) !== 'undefined' && global === window){
	global.RFC4122 = RFC4122;
}